MS and CT list / Aug. 23, 13:20-15:00.

MS [00604] Frontiers of Collaboration with Industry: Towards International Mathematical Commons

room : G301

• [01978] The UniSA Mathematics Clinic: How to build a work-integrated-learning ecosystem
  • Format : Talk at Waseda University
  • Author(s) :
    • Lesley Ann Ward (University of South Australia)
  • Abstract : The University of South Australia Mathematics Clinic runs yearlong authentic industry-sponsored research projects for small teams of final-year undergraduate mathematics students. I will outline how to build the necessary commitment and structure for such a programme, touching on curriculum; articulation with other mathematics courses; coaching students in professional skills and leadership roles; pitching and recruitment of industry sponsors; engaging students and academic staff; intellectual property, confidentiality, and contracts; and scoping and development of suitable projects.
• [02932] Industrial Student Research Programs and Industry Connections at IPAM
  • Format : Talk at Waseda University
  • Author(s) :
    • Christian Ratsch (UCLA)
  • Abstract : The goal of the Institute for Pure and Applied Mathematics (IPAM) is to foster the interaction of mathematics with a broad range of science and technology. In this talk I will review and discuss some of the IPAM activities that are used to fulfill this goal. I will discuss the Research in Industrial Projects for Students (RIPS) program, where undergraduate students work in teams on projects that have been sponsored by an industrial partner.
• [01963] Development of Mathematics for Industry in Japan: New Research Area, Education and Platform
  • Format : Talk at Waseda University
  • Author(s) :
    • Kenji Kajiwara (Institute of Mathematics for Industry, Kyushu University)
  • Abstract : In this talk, we exhibit activities of "Mathematics for Industry" (MfI) in Japan, initiated by the Institute of Mathematics for Industry(IMI), Kyushu University founded in 2011. MfI intends to develop a new research area of mathematics formed by responding to the needs of industries associated with various relevant activities such as education and network/platform formed by mathematicians and mathematical institutes. We present various challenges to realizing the idea of MfI in Japan.
• [01984] APCMfI and International Mathematical Commons for Asia Pacific region
  • Format : Online Talk on Zoom
  • Author(s) :
    • Zainal Abdul Aziz (Universiti Teknologi Malaysia)
  • Abstract : In order to facilitate Mathematics for Industry-MfI within the platform of International Mathematical Commons for Asia Pacific region i.e., encompassing academia, industrial, government and communal sectors; then APCMfI have to implement more effective mechanisms. These include fostering Asia Pacific Study Groups with Industry, proposing Centres of MfI-based in Universities, establishing Asia Pacific Networks, promoting National Networks, supporting Conferences and Workshops on Industrial Problems, Student Programmes and Modelling Camps, Internships and Industry/Academia Exchanges and Consultancy.

MS [00710] Gender Equality in Mathematics: A Global Perspective

room : G302

• [01733] Lessons on the global mathematical community from the 'Gender Gap in Science' global survey.
  • Format : Talk at Waseda University
  • Author(s) :
    • Maria J. Esteban (CNRS and University Paris-Dauphine)
  • Abstract : This talk will present the 'Gender Gap in Science' projet and more specifically the global survey that was carried out in order to better understand the gender gap in Academia, continent by continent, field by field. This will be completed with the description of the main results concerning Mathematics and Applied Mathematics in contrast with other scientific fields.
• [02137] The African perspective about the Gender Gap in Science
  • Format : Talk at Waseda University
  • Author(s) :
    • Sophie Dabo (INRIA- University of Lille)
    • Maria J. Esteban (CNRS and University Paris-Dauphine)
    • Colette Guillopé (University Paris Est Creteil)
    • Marie-Françoise Ouedraogo (University Joseph ki_zeRBO)
    • Marie-Françoise Roy (University of Rennes 1)
  • Abstract : In this talk, we aim to understand the results of the "Gender Gap in Science survey (2017-2019)" for African continent. We analyze in detail the gender gap in Science among scientists who are working in Africa, but also compare those results with the rest of the world, in particular to see how economical and cultural differences can affect the gender gap among scientists. Note that that survey addresses several aspects that often are not measured on bibliographic metadata such as work-life balance, family support, access to resources and sexual harassment. It is important to note also that even if the number of answers was important both in Africa as elsewhere, these numbers are small compared to the whole population of scientists. Also it is necessary to understand that the answers are often subjective because they do not correspond to questions for which the answers are quantifiable, but to how people feel about some particular topic. All this to say that what we are going to state in this talk, is just an image that probably reflects the reality, but that has to be taken with a grain of attention.
• [02048] gender diversity in Japanese concept
  • Format : Talk at Waseda University
  • Author(s) :
    • Motoko KOTANI (Tohoku University)
  • Abstract : Japan is quite behind in gender equality and inclusive perspective. The progress is slow but steady. I would like to present the current situation and actions in Japan, in science in general, and in mathematics.
• [02437] What we can do with Asian-Oceanian Women in Mathematics
  • Format : Talk at Waseda University
  • Author(s) :
    • Yukari Ito (The University of Tokyo)
  • Abstract : Asian-Oceanian Women in Mathematics (AOWM), the continental organization for women in mathematics in Asia and Oceania was established on August 1, 2022. There are more than 200 founding members from 18 Asian and Oceanian countries. We will have the first Inaugural meeting of AOWM in India and hybrid from 24th to 28th April 2023. I will talk about the report of the meeting and what we can do with AOWM.

MS [01834] Structure analysis and dynamics modelling in graphs and networks

room : G304

• [03989] Evolutionary Game Theory on Dynamic Networks
  • Format : Online Talk on Zoom
  • Author(s) :
    • Qi Su (University of St Andrews)
    • Alex McAvoy (University of Pennsylvania)
    • Joshua B. Plotkin (University of Pennsylvania)
  • Abstract : The study of the evolution of cooperative behavior on static networks helps to understand how population structure can facilitate the spread of prosocial traits. However, real-world interactions are usually transient and subject to external restructuring, making the study of strategic behavior on dynamic networks difficult. This study provides an analytical treatment of cooperation on dynamic networks and demonstrates that transitions among network structures can promote the spread of cooperation, even if individual social networks inhibit it when static. The findings highlight the significant impact of dynamic social structures on the evolution of prosocial traits.
• [02059] An efficient adaptive degree-based heuristic algorithm for influence maximization in hypergraphs
  • Format : Online Talk on Zoom
  • Author(s) :
    • Xiu-Xiu Zhan (Hangzhou Normal University)
  • Abstract : Influence maximization (IM) has shown wide applicability in immense fields over the past decades. Previous researches on IM mainly focused on the dyadic relationship but lacked the consideration of higher-order relationship between entities, which has been constantly revealed in many real systems. An adaptive degree-based heuristic algorithm, i.e., Hyper Adaptive Degree Pruning (HADP) which aims to iteratively select nodes with low influence overlap as seeds, is proposed in this work to tackle the IM problem in hypergraphs. Furthermore, we extend algorithms from ordinary networks as baselines. Results on 8 empirical hypergraphs show that HADP surpasses the baselines in terms of both effectiveness and efficiency with a maximally 46.02% improvement. Moreover, we test the effectiveness of our algorithm on synthetic hypergraphs generated by different degree heterogeneity. It shows that the improvement of our algorithm effectiveness increases from 2.66% to 14.67% with the increase of degree heterogeneity, which indicates that HADP shows high performance especially in hypergraphs with high heterogeneity, which is ubiquitous in real-world systems.
• [04046] Identifying vital nodes through augmented random walks on higher-order networks
  • Format : Online Talk on Zoom
  • Author(s) :
    • Xiao-Long Ren (Yangtze Delta Region Institute (Huzhou), University of Electronic Science and Technology of China)
  • Abstract : Identifying vital nodes is still unclear in the study of higher-order networks. We introduce a multi-order graph obtained by incorporating the higher-order bipartite graph and the classical pairwise and propose a Higher-order Augmented Random Walk model. Our model provides a new approach for ranking nodes at multiple scales. Our method outperforms other indicators in identifying vital nodes and can scale to various tasks in complex networks, including the information spread maximization and network dismantling problem.
• [04449] Emergence of Cooperation Through Coevolving Time Scale in Spatial Prisoner's Dilemma
  • Format : Online Talk on Zoom
  • Author(s) :
    • Zhihai Rong (Donghua University)
  • Abstract : Understanding the emergence of cooperation is a challenging problem and has drawn a wide attention from various fields including sociology, economics and biology. Evolutional game theory provides a powerful framework for investigating this problem. In the traditional networked evolutionary game theory, most researchers usually assume an individual will immediately update its strategy after one round of game with its neighbors. However, in the social and biological systems the strategy-selection time scale may be slower than the interaction time scale, i.e., an individual will hold its current strategy and play several rounds of game with its neighbors, and then update its behavior. In this talk, I will introduce some results about coevolving time scale in spatial Prisoner’s dilemma. When the individuals can adjust their strategy-selection time scale according to some rules, optimal cooperation can be induced by proper adaptive rate in the strategy-selection time scale. The results are analyzed through the spatial pattern and feedback mechanism of individual behavior. This investigation may have potential implications in the design of consensus protocol in multi-agent systems.

MS [02154] Hypergeometric functions in statistics and particle physics

room : G305

• [03807] Towards Algebraic Analysis of Hypergeometric Systems
  • Author(s) :
    • Saiei-Jaeyeong Matsubara-Heo (Kumamoto University)
  • Abstract : A hypergeometric function is an analytic function defined in terms of an elementary integral. A hypergeometric system is a system of differential (or difference) equations that it satisfies, which ties analysis to various fields of algebra, such as ring/module theory (D-modules), homological algebra, or combinatorics of polytopes. This talk aims to provide the speaker's view on the current state of the art. A unifying thread is a study of algebraic equations.
• [03843] D-Module Techniques for Solving Differential Equations in the Context of Feynman Integrals
  • Author(s) :
    • Anna-Laura Sattelberger (Department of Mathematics, KTH Royal Institute of Technology)
  • Abstract : I explain how to compute series solutions of regular holonomic D-ideals with Gröbner basis methods via an algorithm due to Saito, Sturmfels, and Takayama. As a point in case, I consider a D-ideal originating from a triangle Feynman diagram. This talk is based on joint work (arXiv:2303.11105) with Johannes Henn, Elizabeth Pratt, and Simone Zoia. Therein, we compare D-module techniques to dedicated methods developed for solving differential equations in the context of Feynman integrals.
• [04120] Distribution of eigenvalues of a singular elliptical Wishart matrix
  • Author(s) :
    • Koki Shimizu (Tokyo University of Science)
    • Hiroki Hashiguchi (Tokyo University of Science)
  • Abstract : We derive the exact distributions of eigenvalues of a singular Wishart matrix under the elliptical model. These distributions cover the results under the Gaussian model as a special case. The joint density of eigenvalues and distribution function of the largest eigenvalue for a singular elliptical Wishart matrix are represented in terms of generalized hypergeometric functions. Numerical computations for the distribution of the largest eigenvalue are conducted under Gaussian and Kotz-type models.
• [04121] Restriction algorithms for holonomic systems and their applications
  • Author(s) :
    • Nobuki Takayama (Kobe University)
  • Abstract : Definite integrals with parameters (in statistics and physics) satisfy holonomic systems (maximally overdetermined systems of linear PDEs). When parameters are restricted to an algebraic set, these integrals satisfy smaller or simpler holonomic systems. We will survey algorithms of finding these smaller or simpler systems with applications and numerical examples.

MS [00353] Interpretable constrained tensor decompositions: models, algorithms, efficient implementations and applications

room : G306

• [03825] Implicit balancing in penalized low-rank approximations
  • Format : Talk at Waseda University
  • Author(s) :
    • Jeremy E. Cohen (CREATIS, CNRS)
  • Abstract : Tensor decompositions are an important tool in machine learning, particularly due to their interpretability which makes them well-adapted to solving inverse problems for a wide range of applications. Additional constraints and penalizations are often imposed to enhance the interpretability of these models. Because of scale-invariance in tensor decompositions, one may show that adding regularization terms, which are scale-dependent, induces an implicit balancing of the factor matrices. By explicitly imposing balancing during an optimization algorithm, I show that it is possible to improve the precision and speed of that algorithm for both nonnegative PARAFAC and Tucker decompositions.
• [02791] Hierarchical and neural nonnegative tensor factorizations
  • Format : Online Talk on Zoom
  • Author(s) :
    • Jamie Haddock (Harvey Mudd College)
    • Joshua Vendrow (Massachusetts Institute of Technology)
    • Deanna Needell (University of California, Los Angeles)
  • Abstract : Nonnegative matrix factorization (NMF) has found many applications including topic modeling and document analysis. Hierarchical NMF (HNMF) variants are able to learn topics at various levels of granularity and illustrate their hierarchical relationship. Recently, nonnegative tensor factorization (NTF) methods have been applied in a similar fashion in order to handle data sets with complex, multi-modal structure. Hierarchical NTF (HNTF) methods have been proposed, however these methods do not naturally generalize their matrix-based counterparts. Here, we propose a new HNTF model which directly generalizes a HNMF model special case, and provide a supervised extension. Our experimental results show that this model more naturally illuminates the topic hierarchy than previous HNMF and HNTF methods. We also describe training methods for hNTF models built upon a neural network structure.
• [03781] Nonnegative canonical tensor decomposition with linear constraints: nnCANDELINC
  • Format : Talk at Waseda University
  • Author(s) :
    • Derek DeSantis (Los Alamos National Labs)
    • Boian Alexandrov (Los Alamos National Labs)
    • Gianmarco Manzini (Los Alamos National Labs)
    • Erik Skau (Los Alamos National Labs)
  • Abstract : Nonnegative tensor factorization produces sparse and easily understandable latent features. However, the Canonical Polyadic Decomposition (CPD) struggles with tensors that have rank deficient factors. The PARALIND algorithm addresses this for real-valued tensors by first computing a Tucker decomposition (TD) and then performing a CPD on the TD core to extract latent features. This work explores the theory behind the nonnegative version of PARALIND. We demonstrate nnPARALIND on several real and synthetic examples, highlighting its sensitivity and discussing when it can be applied.
• [04213] Joint Data Fusion and Blind Unmixing using Nonnegative Tensor Decomposition
  • Format : Online Talk on Zoom
  • Author(s) :
    • Clémence Prévost (University of Lille, CNRS Centrale Lille, UMR 9189 CRIStAL F-59000 Lille, France)
    • Valentin Leplat (Skoltech Center for Artificial Intelligence Technology (CAIT) Moscow, Russia)
  • Abstract : We present a new method for solving hyperspectral super-resolution and spectral unmixing of the unknown super-resolution image. Our method relies on (1) the nonnegative block-term decomposition, (2) joint tensor factorization with multiplicative updates, and (3) the formulation of optimization problems with the beta-divergence. We propose a family of algorithms, adaptable to various noise statistics. Experiments show that our approach competes favorably with state-of-the-art for solving both problems for various noise statistics. , blockterm decomposition,  -divergence, blind spectral unmixing, hyperspectral super-resolution.

contributed talk: CT012

room : G401

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G401
• Type : Contributed Talk
• Abstract : Various studies present mathematical models of ordinary and fractional differential equations to reduce delinquent behavior and encourage prosocial growth. However, these models do not include the fear effect of the judiciary and of other gangs on one criminal gang, which is necessary to depict the behavioral changes of criminals. Hence, this talk will discuss a fractional-order of crime transmission model with the fear effect of the judiciary on offenders with competition effect in different gangs.
• Classification : 26A33, 00A71, 34A08
• Format : Talk at Waseda University
• Author(s) :
  • Trilok Mathur (Birla Institute of Technology and Science, Pilani)
  • Shivi Agarwal (Birla Institute of Technology and Science, Pilani)
  • Komal Bansal (Birla Institute of Technology and Science, Pilani)

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G401
• Type : Contributed Talk
• Abstract : The universally prestarlike functions of order α ≤ 1 in the slit domain Λ = C [1;∞) have been recently introduced by S. Ruscheweyh. This notion generalizes the corresponding one for functions in the unit disk Δ (and other circular domains in C). In this paper, we obtain the Fekete-Szegö inequality for such functions by using Variational Method. We conclude that this paper presents a new class of functions analytic in the slit domain, and closely related to the class of starlike functions. Besides being an introduction to this field, it provides an interesting connections defined class with well-known classes. The paper deals with several ideas and techniques used in geometric function theory.
• Classification : 30C45
• Format : Talk at Waseda University
• Author(s) :
  • Lourthu Mary Joseph (Yuvabharathi International School)

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G401
• Type : Contributed Talk
• Abstract : A thermostat is a device that detects the temperature of a physical system and takes the requisite actions to maintain the system's temperature at a predetermined set point. This paper deals with a fully fractional thermostat model involving Riemann-Liouville fractional derivatives. By choosing an appropriate weighted Banach space of continuous functions, we employ the Banach contraction principle to establish the existence and uniqueness result. An example is presented to validate our theoretical finding.
• Classification : 26A33, 34A08, 34K10, 34K37, 65L10, Fractional differential equations, Riemann-Liouville fractional derivative, Thermostat model, Banach contraction principle, Product rectangle rule, Numerical simulation.
• Format : Online Talk on Zoom
• Author(s) :
  • KIRAN KUMAR SAHA (Indian Institute of Technology Roorkee)
  • NAGARAJAN SUKAVANAM (Indian Institute of Technology Roorkee)

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G401
• Type : Industrial Contributed Talk
• Abstract : In this talk , we found the analytical solution of unsteady free convective flow of an electrically conducting and viscous incompressible fluid between two infinite parallel plates when one plate moves with a ramped velocity. An applied Magnetic field has been taken into consideration. Laplace transform techniques were used to find the non-dimensional governing equations analytically. The effect of various values for magnetic field magnetic parameter, Grashof number and time parameter are demonstrated graphically.
• Classification : 26A33, 33C65, 33C20
• Format : Online Talk on Zoom
• Author(s) :
  • Sangeeta Kumari (Chandigarh University)
  • Vanita Vatsa (Depaertment of Mathematics, DCRUST, Murthal, INDIA)

contributed talk: CT014

room : G402

[00729] q-LAPLACE TRANSFORMS FOR THE PRODUCT OF BASIC ANALOGUE FOR H-FUNCTIONS FOR TWO VARIABLES AND THE GENERAL CLASS OF q-POLYNOMIALS

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G402
• Type : Contributed Talk
• Abstract : The q-Laplace transforms for the product of basic analogue of H-function of two variables and the general class of q-polynomials has been evaluated in the present paper. Few cases of the main outcomes including the applications involving the basic analogues of Fox’s H-functions as well as general class of q-polynomial are also evaluated.
• Classification : 33D60, 44A10, 44A20
• Format : Talk at Waseda University
• Author(s) :
  • Vijay Kumar Vyas (Sur University College,Oman)
  • Ali A. AL-JARRAH (Sur University College,Oman)

[02391] Null controllability of semilinear differential inclusion with nonlocal condition

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G402
• Type : Contributed Talk
• Abstract : We discuss the null controllability of semilinear differential inclusion with the nonlocal condition using $L^p([0, a], U)$ control, where $U$ may be a separable Hilbert space or uniformly convex Banach space. Undoubtedly, exact controllability is much more beneficial than null controllability. But, null controllability plays its role in a system where exact controllability does not hold. Differential inclusion can properly define partial differential equations involving jump discontinuous functions.
• Classification : 34G10
• Format : Talk at Waseda University
• Author(s) :
  • BHOLANATH KUMBHAKAR (DEPARTMENT OF MATHEMATICS, INDIAN INSTITUTE OF TECHNOLOGY ROORKEE)
  • DWIJENDRA NARAIN PANDEY (DEPARTMENT OF MATHEMATICS, INDIAN INSTITUTE OF TECHNOLOGY ROORKEE)

[00363] Neighborhood effects, college education, and social mobility

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G402
• Type : Contributed Talk
• Abstract : This study models the impact of environmental factors on upward social mobility, where the educational environment is measured by the proportion of college-educated individuals, and social mobility is measured by a change in the proportion of people in different income classes. The dynamics of the educational environment are modeled using a modified version of the invasion/extinction ecological model of Richard Levins. The educational environment influences the educational choices of poor people, becoming effective only after a threshold point is reached. The rate of growth in influence is modeled using a monotonically increasing saturation function, which includes a delay parameter referred to as handling time, that measures the speed of influence. Our simulations indicate that poor people choose to become educated at a rate that primarily depends on the density of the local environment.
• Classification : 34-11, 37N40, 92B05
• Format : Online Talk on Zoom
• Author(s) :
  • Cesar Montalvo (University of Virginia)

[01091] Nonlinear effects of neighborhood influence over college education, and social mobility

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G402
• Type : Industrial Contributed Talk
• Abstract : This contagion-effect model studies the impact of environmental factors on upward social mobility, where the educational environment is measured by the proportion of college-educated individuals, and social mobility is measured by a change in the proportion of people in different income classes. The dynamics of the educational environment are modeled using a modified version of the invasion/extinction ecological model of Richard Levins. In addition, the model adapts a version of a SIR-type model to capture the nonlinear effects of the influence of the environment. The educational environment influences the educational choices of poor people, becoming effective only after a threshold point is reached. The growth rate in influence is modeled using a monotonically increasing saturation function, which includes a delay parameter referred to as handling time, that measures the speed of influence generated by educated, successful individuals. The simulations indicate that poor individuals choose to become educated at a rate that primarily depends on the density of educated people acting as role models in the local environment. (This research has been peer-reviewed, accepted, and published by the Socio-Economic Planning Sciences Journal under the name "Neighborhood effects, college education, and social mobility," and all the authors are aware of the submission. This research is expected to contribute to studying the nonlinear dynamical effects of changing environments over socio-economic outcomes).
• Classification : 34-11, 37N40, 92B05
• Author(s) :
  • Cesar Montalvo (University of Virginia)

MS [00669] Mathematical Solutions of Industrial Applications

room : G404

• [02716] Prediction of Leaf Area Index of Tomato Plants by Image Processing and Deep Learning
  • Format : Talk at Waseda University
  • Author(s) :
    • Mario Tsukassa Sato (University of Tsukuba)
    • Aiga Goto (University of Tsukuba)
    • Nanami Isoda (University of Tsukuba)
    • Ayu Kaise (University of Tsukuba)
    • Claus Aranha (University of Tsukuba)
    • Akira Imakura (University of Tsukuba)
    • Tetsuya Sakurai (University of Tsukuba)
    • Naomichi Fujiuchi (Ehime University)
    • Naoya Fukuda (University of Tsukuba)
  • Abstract : In this work, we study how to improve image recognition in greenhouse tomato plants using Machine Learning. We propose a method for non-destructively estimating the Leaf Area Index (LAI), as well as a method to improve the segmentation of different parts of the plant. Moreover, we discuss our investigation of three ways to estimate the relevant parts of the segmented image. Additionally, we investigated new methods to improve the task of semantic segmentation of the whole plant.
• [02893] Frequency based graph estimation for multivariate time-series
  • Format : Talk at Waseda University
  • Author(s) :
    • Yuuya Takayama (Nikon Corporation)
  • Abstract : We propose a method to estimate an underlying graph structure from multivariate time-series data. This method is derived from the Dynamic Mode Decomposition (DMD) method so as to recover an exact graph from a solution of the graph wave equation. In our talk, we introduce its applications and discuss uncertainty of an estimated graph based on the mathematical equation.
• [02900] Passive Gamma Emission Tomography for Spent Nuclear Fuel
  • Format : Talk at Waseda University
  • Author(s) :
    • Riina Virta (Radiation and Nuclear Safety Authority (STUK), and Helsinki Institute of Physics, University of Helsinki)
    • Tatiana Alessandra Bubba (University of Bath)
    • Mikael Moring (Radiation and Nuclear Safety Authority (STUK))
    • Samuli Siltanen (Department of Mathematics and Statistics of the University of Helsinki)
    • Tapani Honkamaa (Radiation and Nuclear Safety Authority (STUK))
    • Peter Dendooven (Helsinki Institute of Physics, University of Helsinki)
  • Abstract : Spent nuclear fuel needs to be verified prior to geological disposal in a deep underground repository. In Passive Gamma Emission Tomography (PGET), the gamma radiation emitted by the fuel is recorded with highly collimated semiconductor detectors and 2D slice images of activity and attenuation are simultaneously reconstructed to account for the high self-attenuation of the material. General information about the object geometry is used as a prior to regularize the ill-posed inverse problem.
• [02901] Boundary estimation of the X-ray tomographic reconstruction using persistent homology
  • Format : Talk at Waseda University
  • Author(s) :
    • Elli Karvonen (University of Helsinki)
  • Abstract : In some applications, one can only use limited-angle X-ray tomography, which results in a much more difficult reconstruction problem than a full-angle case. Despite an algorithm, all parts of the smooth boundaries of the target object cannot be detected stably. In this talk the new boundary estimation method, which utilizes complex wavelets and persistent homology, is presented. The latest results are shown and discussed.

MS [01768] Computer-assisted proofs in differential equations

room : G405

• [04529] Numerical verification methods for ODEs with conservative quantity
  • Format : Talk at Waseda University
  • Author(s) :
    • Nobito Yamamoto (The University of Electro-Communications)
    • Koki Nitta (The University of Electro-Communications)
  • Abstract : We are treating ODEs with conservative quantity and interested in proving existence of time-global solutions remaining in a given sphere with common points on the surface. There is difficulty in computing the solution orbits for a long time due to drift between solutions of conservative systems. Our method is based on verified computation of the conservative quantity and the flow on the surface of the sphere. Numerical examples derived from Schroedinger equation will be shown.
• [04834] Computer-assisted Existence Proofs for Navier-Stokes Equations on an Unbounded Strip with Obstacle
  • Format : Talk at Waseda University
  • Author(s) :
    • Michael Plum (Karlsruhe Institute of Technology)
    • Jonathan Wunderlich (Karlsruhe Institute of Technology)
  • Abstract : The incompressible stationary 2D Navier-Stokes equations are considered on an unbounded strip domain with a compact obstacle. A computer- assisted existence and enclosure result for the velocity (in a suitable diver- gence-free Sobolev space) is presented. Starting from a numerical approximate solution (computed with divergence-free finite elements), we determine a bound for its defect and a norm bound for the inverse of the linearization at the approximate solution. For the latter, bounds for the essential spectrum and for eigenvalues close to zero of an associated self-adjoint operator play a crucial role. To obtain the desired lower bounds for the eigenvalues below the essential spectrum we use a combination of the Rayleigh-Ritz method, a corollary of the Temple-Lehmann-Goerisch theorem and a homotopy method.
• [04194] Relative equilibria for the n-body problem
  • Format : Talk at Waseda University
  • Author(s) :
    • Warwick Tucker (Monash University)
    • Jordi-Lluis Figueras (Uppsala University)
    • Piotr Zgliczynski (Jagiellonian University)
  • Abstract : We will discuss the classical problem from celestial mechanics of determining the number of relative equilibria a set of planets can display. Several already established results will be presented, as well as a new contribution (in terms of a new proof) for the restricted 4-body problem. We will discuss its possible extensions to harder instances of the general problem.
• [05267] Chaos in Mackey-Glass: computation of transverse homoclinic orbits
  • Format : Talk at Waseda University
  • Author(s) :
    • Olivier Hénot (McGill University University)
  • Abstract : The Mackey-Glass equation is a scalar delay differential equation, famous for its rich dynamics. Since 1977, the equation has become a primary example of chaos in infinite dimensions. Yet, a proof of existence of chaotic dynamics remains an open problem. In this talk, we present a computational method for studying transverse homoclinic orbits for periodic solutions of delay differential equations. The connection is formulated as the zero of a nonlinear map representing a boundary value problem, with boundary conditions in the (finite dimensional) unstable and (infinite dimensional) stable manifolds of the periodic orbit; the transversality of the intersection is a by-product of the invertibility of the Fréchet derivative of the map. This technique is designed to be amenable for computer-assisted proofs through a Newton-Kantorovich type argument. As a notable illustration, we compute a transverse homoclinic orbit in the Mackey-Glass equation.

MS [00278] Nonlocal Modeling, Analysis, and Computation

room : G406

MS [00068] Models for collective behavior and emergent phenomena

room : G501

MS [00072] Evolution equations in materials science: Multiscale modeling, analysis, and simulation

room : G502

• [04859] Diffusion in the presence of microstructures: Does vesicle micro-dynamics enhance the signalling among plants macro-transport?
  • Format : Talk at Waseda University
  • Author(s) :
    • Adrian Muntean (Karlstad University)
    • Sander Hille (Leiden University)
    • Omar Richardson (Simula Consulting)
  • Abstract : We study a diffusion-drift problem for signalling among plants in the context of measure-valued equations. We show preliminary results concerning the modelling and mathematical analysis of scenarios involving the macroscopic diffusion of signalling molecules enhanced by a finite number of microvesicles, with own dynamics able to capture and release signals as a relay system. The macro-micro coupling relies on a two-scale transmission condition. Mild solutions will turn to exist and will be positive weak solutions.
• [04217] Morphology formation in ternary mixtures: A continuum model
  • Format : Talk at Waseda University
  • Author(s) :
    • Rainey Lyons (Karlstad University)
  • Abstract : We study the ability of a coupled nonlocal system of two quasilinear parabolic partial differential equations to produce phase separation patterns. This system is derived in the literature as the rigorous hydrodynamic limit of a suitably scaled interacting particle system of Blume–Capel–type driven by Kawasaki dynamics. In this talk, we will discuss the potential of the model to produce morphologies, the growth of these patterns, well-posedness, and regularity of solutions.
• [05044] Homogenisation of an advection–reaction–diffusion process in a porous medium with coupled evolving microstructure
  • Format : Talk at Waseda University
  • Author(s) :
    • Markus Gahn (Heidelberg University)
    • Malte A. Peter (University of Augsburg)
    • Iuliu Sorin Pop (Hasselt University)
    • David Wiedemann (University of Ausgburg)
  • Abstract : We consider the homogenization of an advection–reaction–diffusion equation in an evolving porous medium. The microstructure's evolution is coupled with the unknown concentration of a substance, resulting in a free boundary value problem. To rigorously pass to the homogenization limit, we transform the problem into a periodic fixed domain, which results in a highly non-linear problem. We then pass to the homogenization limit.
• [04239] Partial differential equations for moisture transport in porous materials
  • Format : Talk at Waseda University
  • Author(s) :
    • Akiko Morimura (Japan Women's University)
    • Toyohiko Aiki (Japan Women's Univeristy)
  • Abstract : We consider the initial-boundary value problems for nonlinear parabolic equations describing moisture transport in a porous material. As a first step in this research, we suppose that the mass distribution in air is given and propose the problem for equation called ellipitic-parabolic type. The purpose of this talk is to establish existence and uniqueness of solutions to the approximate problem by applying the evolution equation theory and the standard fixed-point argument.

contributed talk: CT034

room : G601

[02489] $L^p$-estimates for Maxwell's equations in heterogeneous materials

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G601
• Type : Contributed Talk
• Abstract : Estimates for the time-harmonic Maxwell's equations in heterogeneous materials are concerned. The materials contain two constituents. One high-conductivity constituent of small size is embedded in each period so that it is disconnected. The other of low-conductivity constituent contains the rest of the material. The contrast ratios of the conductivity and the magnetic permeability in one constituent to the other can be very high. Here $L^p$-estimates for the electromagnetic fields uniform in contrast ratios are presented.
• Classification : 35J70, 35J25, 35J75
• Format : Talk at Waseda University
• Author(s) :
  • Li-Ming Yeh (National Yang Ming Chiao Tung University)
  • Dongwoo Sheen (Seoul National University)

[00991] Applied mathematics applications in ocean engineering

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G601
• Type : Industrial Contributed Talk
• Abstract : A novel controller technique using nonlinear quadratic regulatory framework is proposed, the algorithm perform the parameterization of the nonlinear model of the system such that the linearized model remains transversal everywhere to nonlinear model leading to control of original model. By transversality, linearized and nonlinear solutions intersect at only grid points on time axis without using Taylor-like expansions and shown its applicability in SWT
• Classification : 37D10
• Format : Talk at Waseda University
• Author(s) :
  • MANIKANDAN RAJASEKARAN (UGC-DR DS KOTHARI POST DOCTORAL FELLOW DEPARTMENT OF APPLIED MATHEMATICS BHARATHIYAR UNIVERSITY COIMBATORE TAMIL NADU INDIA)
  • SATARUPA DEY (Assistant Professor and Head Department of Botany Shyampur Siddheswari Mahavidyalaya (Affiliated to University of Calcutta) West Bengal India)
  • SAKTHIVEL R (DEPARTMENT OF APPLIED MATHEMATICS BHARATHIYAR UNIVERSITY COIMBATORE TAMIL NADU INDIA)

[00388] Numerical solution of distributed order time-fractional diffusion equations.

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G601
• Type : Contributed Talk
• Abstract : In this work, we solved distributed order time-fractional diffusion equation with the help of a wavelet approximation scheme and the Gauss quadrature rule. First, we construct wavelet-based operational matrices of distributed order fractional derivatives and integer order derivatives. After the construction of the operational matrix apply the tau method and convert the original mathematical problem into a system of linear algebraic equations and solve the equations for finding the approximate solutions. For method validation, we have provided some test examples, convergence analysis, and error estimation, and verify with the existing scheme with one of the existing schemes.
• Classification : 35J99, 65N35, 65N99
• Format : Online Talk on Zoom
• Author(s) :
  • Yashveer Kumar (Indian Institute of Technology(BHU), Varanasi, India.)
  • Vineet Kumar Singh (Department of Mathematical Sciences, Indian Institute of Technology (Banaras Hindu University), Varanasi, India.)

[01083] The existence and the numerical approximation to a nonlinear coupled system in anisotropic Orlicz-Sobolev spaces

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G601
• Type : Contributed Talk
• Abstract : We study the existence of a capacity solution for a nonlinear elliptic coupled system in anisotropic Orlicz-Sobolev spaces. The unknowns are the temperature inside a semiconductor material, and the electric potential. This system may be considered as a generalization of the steady-state thermistor problem. The numerical solution is also analyzed by means of the least squares method in combination with a conjugate gradient technique.
• Classification : 35J70, 35J66, 35K61, 46E30, 65N22
• Format : Online Talk on Zoom
• Author(s) :
  • Hakima Ouyahya (Moulay Ismail University)

[00398] Approximation of Abel type nonlinear fractional integral equations by the use of orthogonal polynomials

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G601
• Type : Contributed Talk
• Abstract : The nonlinear fractional integral equations of the type Abel are presented in this study with general framework for determining the approximate solution. As basis functions, this method makes use of Lagrangian interpolating polynomials (LIPs) and shifting Legendre polynomials (SLPs). The original problem is converted into a system of algebraic nonlinear equations using operational matrices of SLPs and LIPs, which are first developed. We investigated at the provided techniques' stability and convergence under several significant conditions.
• Classification : 35J99, 65N35, 65N99
• Author(s) :
  • Aman Singh (Department of Mathematical Sciences, Indian Institute of Technology (Banaras Hindu University))
  • Vineet Kumar Singh (Department of Mathematical Sciences, Indian Institute of Technology (Banaras Hindu University))

MS [00061] Reaction-Diffusion models in Ecology and Evolution

room : G602

• [00123] Propagation direction of the traveling wave in the Lotka-Volterra competition-diffusion system
  • Format : Talk at Waseda University
  • Author(s) :
    • Chiun-Chuan Chen (National Taiwan University)
  • Abstract : We consider the two species Lotka-Volterra competition-diffusion system and assume that the species are in strong competition. It is well-known that up to a translation, there exists a unique monotone traveling wave solution. The sign of the wave speed provides significant information about which species can wipe out the other. However, it is a difficult problem to determine the sign of the speed. In this talk, we will present some estimates for the relation between the wave speed and the growth rates of the species. With these estimates, we are able to determine the speed sign under some suitable conditions.
• [00124] Principal eigenvalue problem with large advection in 2 dimensional case
  • Format : Talk at Waseda University
  • Author(s) :
    • Maolin Zhou (Nankai University)
  • Abstract : In this talk, we will discuss the recent progress on the limit of the principal eigenvalue of some second order operators with large advection: 1. degenerate case; 2. parabolic case (1-d); 3. elliptic case (2-d).
• [00099] Some game theoretical models in population dynamics
  • Format : Talk at Waseda University
  • Author(s) :
    • Idriss Mazari-Fouquer (CEREMADE, Paris Dauphine Université, PSL)
  • Abstract : We review several recent contributions aimed at providing a better understanding of optimal fishing strategies in spatial ecology: how should one fish in order to maximise the fishing output? If several players are fishing, can they reach an equilibrium situation? Formulated in terms of optimal control problems and Nash equilibria properties, these problems are amenable to mathematical analysis, and we present a variety of related results. Joint work with D. Ruiz-Balet.
• [00125] Free boundary problem for the curve shortening flow with driving force in undulating cylindrical domains
  • Format : Talk at Waseda University
  • Author(s) :
    • Ryunosuke Mori (Meiji University)
  • Abstract : We study a free boundary problem for the curve shortening flow with driving force in a two-dimensional cylindrical domain with periodically undulating boundary. We consider the large time behavior of the graph-like solution. The classical solution generally does not exist in global time, since the solution may touch the boundary of the domain in finite time. To overcome this difficulty, we prove that the set of singularities of the solution is discrete under some assumptions.

MS [01043] Applications of applied mathematics towards ocean engineering and related technologies

room : G605

• [01637] Robust control design for an autonomous underwater vehicle with uncertain dynamics
  • Format : Online Talk on Zoom
  • Author(s) :
    • Antony Crispin Sweety Charles Selvaraj (Avinashilingam Institute for Home Science and Higher Education for Women, Coimbatore)
  • Abstract : In this talk, we consider the robust control problem for autonomous underwater vehicles in the presence of nonlinearities and uncertainties. The aim is to obtain a robust controller in order to maneuver to any given point and track a moving target in the presence of parametric uncertainty and external disturbances. Specifically, the proposed state feedback robust controller guarantees the closed-loop system stability in the sense of the Lyapunov stability theory. Finally, simulation results are provided to verify the effectiveness of the control design.
• [01719] Particle swarm optimization based robust controller for autonomous underwater vehicle
  • Format : Online Talk on Zoom
  • Author(s) :
    • Pankajavalli Palanisamy Balamani (Bharathiar University)
    • Abinandhitha Radhakrishnan (Bharathiar University)
  • Abstract : The purpose of this work is to design a Particle Swarm Optimization (PSO) based controller in a systematic way to get the superior performance and robustness of the considered autonomous underwater vehicle model. Further, simulation results demonstrated the effectiveness of the proposed controller. The developed controller provides faster convergence to the change of parameters as compared to the conventional state feedback controller, for the stabilization of the closed-loop systems with external disturbances.
• [01959] Applications of applied mathematics towards dynamic control of multi-dimensional structures
  • Format : Online Talk on Zoom
  • Author(s) :
    • Payel Chaudhuri (IIT KHARAGPUR)
  • Abstract : This work addresses an evolutionary optimal dynamic inversion algorithm-based semi-active controller for vibration reduction. The proposed inverse control algorithm is established on robust mathematical conceptualization and is ideal with semi-active magnetorheological dampers. The optimum voltage estimated from the proposed controller aid in generating the required control force from the MR dampers to the structures under dynamic loading. The resilience of the proposed inverse control algorithm is evaluated employing various seismic time histories on a multi-dimensional structure.
• [01807] Ship maneuvering in waves
  • Format : Talk at Waseda University
  • Author(s) :
    • Rameesha T V (Scientist B)
    • Krishnankutty P (Professor (Retired))
  • Abstract : Poor controllability of a surface ship is considered as a major cause for most of the marine accidents, which may result in loss of life and property. The present proposal is focused on the prediction of ship maneuvering in waves. Mathematical model for maneuvering prediction is modified for wave condition. The steering and turning characteristics of a container ship in still water and wave condition are compared experimentally and numerically.

MS [00733] Compressible fluid dynamics and related PDE topics

room : G606

• [01289] Time-asymptotic stability of Riemann solutions to the compressible Navier-Stokes equations
  • Format : Talk at Waseda University
  • Author(s) :
    • Yi Wang (AMSS, Chinese Academy of Sciences)
  • Abstract : The talk is concerned with our recent developments on the time-asymptotic stability of generic Riemann solutions to the one-dimensional compressible Navier-Stokes equations including both isentropic and full cases.
• [01339] Stability analysis of Prandtl expansions for two dimensional MHD equations in Sobolev spaces
  • Format : Talk at Waseda University
  • Author(s) :
    • Feng Xie (Shanghai Jiao Tong University)
  • Abstract : In this talk, I will review briefly the classical Prandtl boundary layer expansions method to analyze the structure of viscous flow under the high Reynolds number. And then I will discuss the vanishing viscosity limit of solution to initial boundary value problem for both incompressible and compressible magneto-hydrodynamics (MHD) equations in Sobolev spaces, where the velocity is always imposed the no-slip boundary condition. The effects of the normal component of magnetic field, tangential component of magnetic field, magnetic diffusion and the change of density on the mathematical analysis for stability of MHD boundary layer and vanishing viscosity limit of solution to MHD equations will be addressed.
• [01378] Global Strong and Weak Solutions to Compressible MHD System
  • Format : Talk at Waseda University
  • Author(s) :
    • Xiaoding Shi (Beijing University of Chemical Technology)
  • Abstract : The barotropic compressible magnetohydrodynamic equations in a general two-dimensional bounded simply connected domain is considered here. For initial density allowed to vanish, we prove that the initial-boundary-value problem of 2D compressible MHD system admits the global strong and weak solutions without any restrictions on the size of initial data.
• [01436] Inviscid Limit Problem of radially symmetric stationary solutions for compressible Navier-Stokes equation
  • Format : Talk at Waseda University
  • Author(s) :
    • itsuko hashimoto (kanazawa university)
    • Akitaka Matsumura (Osaka university)
  • Abstract : The present paper is concerned with an inviscid limit problem of radially symmetric stationary solutions for an exterior problem in R^n (n≧2) to compressible Navier-Stokes equation, describing the motion of viscous barotropic gas without external forces, where boundary and far field data are prescribed. For both inflow and outflow problems, the inviscid limit is considered in a suitably small neighborhood of the far field state. For the outflow problem, we prove the uniform convergence of the Navier-Stokes flows to the Euler flows in the inviscid limit. On the other hand, for the inflow problem, we show that the Navier-Stokes flows uniformly converge to a superposition of boundary layer solution and Euler flows in the inviscid limit. The estimates of algebraic rate toward the inviscid limit are also obtained.

MS [00783] PDE Eigenvalue Problems: Computational Modeling and Numerical Analysis

room : G701

• [01926] Eigenvalues in Inverse Scattering
  • Format : Talk at Waseda University
  • Author(s) :
    • Peter Monk (University of Delaware)
  • Abstract : Transmission eigenvalues can be determined from multistatic scattering data over a range of frequencies and have been suggested as target signatures in inverse scattering. To avoid the need for data over a range of frequencies other artificial eigenvalue problems can be derived by modifying the far field operator. We shall consider “modified transmission eigenvalues” for thin structures. Numerical results will show that a few eigenvalues of each type can be determined from multi-static scattering data.
• [01744] Inverse eigenvalue problems for inferring crystal structure from neutron scattering data
  • Format : Talk at Waseda University
  • Author(s) :
    • Guannan Zhang (Oak Ridge National Laboratory)
  • Abstract : We are interested in inferring the atomic structure of crystal materials from neutron scattering data. The atomic structure is modeled by a parameterized Hamiltonian matrix and the measurements in neutron scattering experiments are the eigenvalues and functionals of the eigenvectors of the Hamiltonian matrix. The goal is to find the optimal parameter in the Hamiltonian matrix to match the scattering data. The main challenge is that the spectrum of the Hamiltonian matrix is very sensitive to its parameters, which leads to a very rough loss landscape. To address this issue, we propose a new loss function that utilize the characteristic polynomial of the Hamiltonian matrix as the loss function. When a matrix has the same eigenvalues as the measurement data, the characteristic loss is zero. Our experiments show that the new loss has a much smoother landscape for an optimization algorithm to find a satisfactory solution. We have demonstrated the effectiveness of our approach in solving the crystal field parameters from neutron scattering data.
• [01689] Application of Prolate Eigensystem to Born Inverse Scattering
  • Format : Talk at Waseda University
  • Author(s) :
    • Shixu Meng (Academy of Mathematics and Systems Science, Chinese Academy of Sciences)
  • Abstract : This talk discusses the application of generalized prolate spheroidal wave functions and eigenvalues (in short prolate eigensystem) to Born inverse scattering problems. We first establish a Picard criterion to reconstruct the contrast. Further motivated by a Sturm-Liouville theory associated with the prolate eigensystem, we give a spectral cutoff regularization for noisy data and an explicit stability estimate for contrast in $H^s$, $0
• [01864] Computational tools for exploring eigenvector localization
  • Format : Talk at Waseda University
  • Author(s) :
    • Jeffrey Ovall (Portland State University)
    • Robyn Reid (Portland State University)
  • Abstract : It is well-known that waves can often be decomposed as an infinite sum where each term in the sum is a product of a function varying only in time and a function varying only in space. The spatial functions are often called standing waves in this context, and are eigenvectors of a spatial differential operator associated with the medium through which the waves are propagating. It is not as well-known that properties of the medium can cause some eigenvectors to be strongly spatially localized. A practical consequence of eigenvector localization is that waves at certain frequencies can be ``trapped'' at some location or ``channelled'' along some favorable path. Such features are of interest in the design of structures having desired acoustic or electromagnetic properties: sound-mitigating outdoor barriers and next generation organic LEDs and solar cells are examples of this design principle in action. There remain many open problems related to understanding and exploiting this kind of localization, and we will discuss a computational approach that we expect will provide useful insight. More specifically, we focus on the issue of eigenvector localization, outlining our computational approach and providing theoretical, heuristic, and empirical support for it through several examples (with many pictures).

MS [00049] Interfaces between kinetic equations and many-agent social systems. Part II

room : G702

• [04948] Weak couplings of Lohe type aggregation models
  • Format : Online Talk on Zoom
  • Author(s) :
    • Seung Yeal Ha (Seoul National University)
    • Dohyun Kim (Sungkyunkwan University)
    • Hansol Park (Simon Fraser University)
  • Abstract : In this talk, we present a systematic algebraic approach for the weak coupling of Cauchy problems to multiple Lohe tensor models. For this, we identify an admissible Cauchy problem to the Lohe tensor (LT) model with a characteristic symbol consisting of four tuples in terms of a size vector, a natural frequency tensor, a coupling strength tensor and admissible initial configuration. In this way, the collection of all admissible Cauchy problems to the LT models is equivalent to the space of characteristic symbols. On the other hand, we introduce a binary operation, namely fusion operation" as a binary operation between characteristic symbols. It turns out that the fusion operation satisfies an associativity and admits the identity element in the space of characteristic symbols which naturally forms a monoid. By virtue of the fusion operation, the weakly coupled system of multi tensor models can be obtained by applying the fusion operation of multiple characteristic symbols corresponding to the Lohe tensor models. As a concrete example, we consider a weak coupling of the swarm sphere model and the Lohe matrix model, and provide sufficient framework leading to emergent dynamics to the proposed weakly coupled model. This is a joint work with Dohyun Kim (Sungshin Women’s Univ.) and Hansol Park (Simon Fraser Univ.)
• [03897] Quantified overdamped limit for Kinetic Vlasov-Fokker-Planck equations
  • Format : Talk at Waseda University
  • Author(s) :
    • Oliver Tse (Eindhoven University of Technology)
    • Young-Pil Choi (Yonsei University)
  • Abstract : The study of the overdamped limit for the kinetic Fokker-Planck equation has been of interest since the seminal work of Kramers in 1940, where he formally discussed the convergence by introducing a coarse-graining map. This talk is based on work with Young-Pil Choi, where we provide a framework to establish quantitative estimates for the overdamped limit of the kinetic Vlasov-Fokker-Planck with singular interaction in terms of the 2-Wasserstein distance. 
• [04724] Phase-coupled models for synchronization with nonlocal temporal interactions
  • Format : Talk at Waseda University
  • Author(s) :
    • Myeongju Kang (Korea Institute for Advanced Study)
  • Abstract : We study the emergent dynamics and global well-posedness of the Kuramoto model with memory effect, which is a system of Volterra-type integro-differential equations on unit circle. We adopt nonlocal temporal interactions to design synchronized behavior of oscillators affected by memories of the past. We first establish the global well-posedness of the Kuramoto model with memory effect, and provide sufficient frameworks for uniform boundedness of the phase diameter. Then, we define an energy functional whose boundedness is guaranteed by the boundedness of the phase diameter. We show that energy functional is monotonically decreasing, which implies complete frequency synchronization. Moreover, when natural frequencies are all identical we show the emergence of complete phase synchronization.
• [04208] Rigorous derivation of the Euler-Alignment model with singular communication weights from a kinetic Fokker-Planck-Alignment model
  • Format : Online Talk on Zoom
  • Author(s) :
    • Young-Pil Choi (Yonsei University)
    • Jeongho Kim (Kyung Hee University)
  • Abstract : We present a rigorous derivation of the isothermal Euler-alignment model with singular communication weights. We consider a hydrodynamic limit of a kinetic Fokker-Planck-alignment model, which is the nonlinear Fokker-Planck equation with the Cucker-Smale alignment force. Our analysis is based on the estimate of relative entropy between macroscopic quantities, together with careful analysis on the singular communication weights.

contributed talk: CT044

room : G703

[01047] Large Deviations for Two-Dimensional Stochastic Tidal Dynamics Equations driven by Levy Noise

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G703
• Type : Contributed Talk
• Abstract : The objective is to establish a Wentzell-Freidlin type large deviation principle (LDP) for solution of stochastic tidal dynamics equations driven by Levy Noise. The LDP is equivalent to the Laplace principle in a Polish space. The solution space of the considered equation is Polish. Hence Laplace principle will be established for the stochastic tidal dynamics equations using weak convergence approach for non-negative functionals of a general Poisson random measure and Brownian motion.
• Classification : 35Q35, 60H15, 60G65, 60F10
• Format : Talk at Waseda University
• Author(s) :
  • HASEENA A (Assistant Professor, Government College Chittur)

[01641] Cut singularity of compressible Stokes flow

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G703
• Type : Contributed Talk
• Abstract : In this talk we study the cut singularity governed by a compressible Stokes system. The cut is a non-Lipshitz boundary. The divergence of the leading corner singularity vector has different trace values on either sides of cut. In the consequence the pressure solution must have a jump across the streamline emanating from the cut tip. We establish a piecewise regularity of the solution by subtracting the related singular functions.
• Classification : 35Q35, 76N10, 76F50
• Format : Talk at Waseda University
• Author(s) :
  • Tae Yeob Lee (Pohang University of Science and Technology)
  • Jae Ryong Kweon (Pohang University of Science and Technology)

[01840] On the inviscid limit of the stochastic Navier-Stokes equation

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G703
• Type : Contributed Talk
• Abstract : We study the asymptotic behavior of solutions to the two-dimensional stochasitc Navier-Stokes (SNS) equation in the small viscosity limit. The SNS equation is supplemented with no-slip boundary condition, in which a strong boundary layer shall appear in the limit. Several equivalent dissipation conditions are derived to ensure the convergence hold in the energy space. One novelty of this work is that we do not assume any smallness for the noise.
• Classification : 35Q35, 60H15, 76D10
• Format : Talk at Waseda University
• Author(s) :
  • Meng Zhao (Shanghai Jiao Tong University)
  • Ya-Guang Wang (Shanghai Jiao Tong University)

MS [00496] Recent development in Quantum Simulation and Stochastic Methods

room : G704

• [02786] Orthogonalization and Orthogonalization-free Algorithms
  • Format : Talk at Waseda University
  • Author(s) :
    • Weiguo Gao (Fudan University)
  • Abstract : This talk consists of two parts. Orthogonalization algorithms are discussed in the first part. And we extend the error analysis result for shiftedCholeskyQR3 algorithm in oblique inner product and show that the new error bound is optimal. We also discuss the loss of orthogonality and verify our conclusions through numerical experiments. This is joint work with Rentao Xu. In the second part, orthogonalization-free algorithms are proposed to solve extreme eigenvalue problems. These algorithms achieve eigenvectors instead of eigenspace. Global convergence and local linear convergence are discussed. Efficiency of new algorithms are demonstrated on random matrices and matrices from computational chemistry. This is joint work with Yingzhou Li and Bichen Lu.
• [01872] Frozen Gaussian Sampling for mixed quantum-classical dynamics
  • Format : Talk at Waseda University
  • Author(s) :
    • Zhennan Zhou (Peking University)
    • Zhen Huang ( University of California, Berkeley)
    • Limin Xu ( Tsinghua University)
  • Abstract : In this article, we propose a Frozen Gaussian Sampling (FGS) algorithm for simulating nonadiabatic quantum dynamics at metal surfaces with a continuous spectrum. This method consists of a Monte-Carlo algorithm for sampling the initial wave packets on the phase space and a surface-hopping type stochastic time propagation scheme for the wave packets. We prove that to reach a certain accuracy threshold, the sample size required is independent of both the semiclassical parameter and the number of metal orbitals, which makes it one of the most promising methods to study nonadiabatic dynamics. The algorithm and its convergence properties are also validated numerically. Furthermore, we carry out numerical experiments including exploring the nuclei dynamics, electron transfer, and finite-temperature effects, and demonstrate that our method captures the physics which can not be captured by classical surface hopping trajectories.
• [02280] The Random Feature Method for Time-dependent Problems
  • Author(s) :
    • Jingrun Chen (University of Science and Technology of China)
    • Weinan E (Peking University)
    • Yixin Luo (Suzhou Institute for Advanced Research, University of Science and Technology of China)
  • Abstract : We propose to solve time-dependent partial differential equations in the framework of random feature method. The approximate solution is constructed using space-time partition of unity and random feature functions, and is proved to enjoy the universal approximation property. The resulting least-squares problem can be solved using two different strategies, and the corresponding error estimates are provided.
• [02728] Numerical methods for disordered NLS
  • Format : Talk at Waseda University
  • Author(s) :
    • Xiaofei Zhao (Wuhan University)
  • Abstract : In this talk, I will consider the numerical solution for the disordered nonlinear Schrodinger equation (NLS). The model is a standard cubic NLS with a spatial random potential. The roughness and/or randomness of the potential brings some numerical difficulties. The performance of some classical time integrators will reviewed, and the low-regularity integrator will be applied to tackle the possible roughness. Then, a quasi-Monte Carlo time-splitting method will be considered to tackle the randomness and improve the sampling accuracy. The full error bound will be presented and numerically verified.

contributed talk: CT045

room : G709

[00599] Advances on estimation of temperature and moisture of soil using sensor networks.

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G709
• Type : Industrial Contributed Talk
• Abstract : Given a sensor network set up on an agricultural field, we review methods based on PDE, regression and Principal Component Analysis algorithms to estimate the temperature and moisture of soil. With PCA it is possible to identify those sensors or groups of sensors which are influential at the time of measuring the temperature or moisture at a given point of the field. Validation results are provided based on real data from agricultural fields.
• Classification : 35Q79, PDE, regression, PCA
• Format : Talk at Waseda University
• Author(s) :
  • Carlos Fresneda-Portillo (Universidad Loyola Andalucía (Spain))
  • Carmelina Ierardi (Universidad Loyola Andalucía )
  • José Ramón Salvador-Ortiz (Universidad Loyola Andalucía)
  • Javier Pérez (Universidad Loyola Andalucía )
  • Diego Luis Orihuela (Universidad Loyola Andalucía )

[00688] Recovering Battery Ageing Dynamics with Invertible Neuronal Networks

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G709
• Type : Contributed Talk
• Abstract : Modern Lithium-Ion-Batteries (LIBs) suffer from degradation. This leads to a dependency of the voltage-capacity-curve on the charge-discharge-cycle. However, there are different processes inducing this degradation, each with a different influence on the aforementioned curve. Given such a curve, we recover the ageing dynamic of each effect and identify how much it contributes to the overall degradation using Invertible Neuronal Networks.
• Classification : 35Q79, 62F15, 35B27, 65M60
• Format : Talk at Waseda University
• Author(s) :
  • Alireza Selahi (Weierstraß Institute for Applied Analysis and Stochastics)
  • Manuel Landstorfer (Weierstraß Institute for Applied Analysis and Stochastics)

[00427] Numerical Analysis of Finite dimensional approximations in Finite Temperature DFT

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G709
• Type : Contributed Talk
• Abstract : We study the numerical approximation of the ground state solution in finite temperature density functional theory. We formulate the problem with respect to the density matrix, and justify the convergence of the numerical approximations of the ground state. Finally, we give a quasi-optimal a priori error estimate with some mild assumptions. We also present some numerical experiments to support the theory.
• Classification : 35Q55, 65N15, 65N25, 65N30
• Format : Talk at Waseda University
• Author(s) :
  • Ge Xu (Beijing Normal University)

[00671] A new drone swarm model for zone occupation

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G709
• Type : Contributed Talk
• Abstract : We focus on fluid modeling for decentralized fleets of autonomous drones with Newtonian models. The corresponding system of hyperbolic conservation laws is obtained through mean field limit and moments closure assumption. The objective is to reduce the complexity for swarm tasks simulations such as zone occupation. Taking advantage of the macroscopic representation of the density, we introduce a new model for this task accounting for the drones inertia, which has been neglected so far.
• Classification : 35Q70, 35B40, 35B45
• Format : Talk at Waseda University
• Author(s) :
  • Axel Maupoux (ONERA / Institut Mathématique de Toulouse)
  • Guillaume Dufour (ONERA)

[01789] On uniqueness of multi-bubble blow-up solutions and multi-solitons to L^2-critical NLS

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G709
• Type : Contributed Talk
• Abstract : This talk is concerned with the long-time behavior of solutions to the focusing $L^2$-critical nonlinear Schrodinger equations. Firstly, we briefly review the existence and uniqueness of multi-bubble blow-up solutions and multi-solitons in the context of NLS. Then, we introduce the uniqueness for a large energy class of multi-bubble blow-up solutions, which converge to a sum of $K$ pseudo-conformal blow-up solutions particularly with the low rate $(T-t)^{0+}$. Lastly, we also discuss the uniqueness of multi-solitons which converge to a sum of $K$ solitary waves with convergence rate $(1/t)^{2+}$ in the energy space, and with even lower convergence rate $(1/t)^{1/2+}$ in the pseudo-conformal space. The talk is based on the joint work with Prof. Daomin Cao and Prof. Deng Zhang, which has been published in "Archive for Rational Mechanics and Analysis" in 2023.
• Classification : 35Q55, 35B44, 35C08
• Format : Online Talk on Zoom
• Author(s) :
  • Yiming Su (Zhejiang University of Technology)

contributed talk: CT046

room : G710

[00929] On the continuum limit of epidemic models on graphs

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G710
• Type : Contributed Talk
• Abstract : We consider an epidemic model defined on graphs and study the asymptotic behavior of the solutions as the number of vertices in the graph diverges. By relying on the theory of (graphons) we provide a characterization of the limit and establish convergence results. We also present approximation results for both deterministic and random discretizations. The analysis applies to dense and sparse graphs, including power-law networks. Extensive numerical results illustrate and assess the analytical findings.
• Classification : 35Q92, 05C99, 92D30, 65M22, 35R02
• Format : Talk at Waseda University
• Author(s) :
  • blanca ayuso de dios (universita milano-bicocca)
  • Simone Dovetta (Politecnico di Torino)
  • Laura Spinolo (IMATI-CNR, Pavia)

[00681] A revised Hughes model for pedestrian flow

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G710
• Type : Contributed Talk
• Abstract : In this talk, we analyse the modified Hughes model for pedestrian dynamics, in which individuals seek to minimize their travel time. We present the existence and uniqueness of the solution and illustrate the behavior of the model with various numerical results. This is joint work with Prof Nader Masmoudi
• Classification : 35Q91, 35Q70, 35F21
• Format : Talk at Waseda University
• Author(s) :
  • Mohamed Ghattassi (NYUAD)

[01790] Numerical simulation of two-layer shallow-water models: Application to Maximal Exchange at Lombok Strait

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G710
• Type : Industrial Contributed Talk
• Abstract : We investigate the generation of internal waves in the Lombok Strait due to semi-diurnal tides using the momentum-conserving staggered grid (MCS) scheme. We first simulate the steady interface representing the maximum exchange flows, which has two controls located at Karangasem Narrows (KN) and Nusa Penida Sill (NPS). Next, the transport volume due to semidiurnal tides is calculated. Finally, internal wave activity near the KRI Nanggala 402 shipwreck site is analysed.
• Classification : 35Q86, 76M20, 65Mxx, Computational Fluid Dynamics (internal waves, internal hydraulics)
• Format : Online Talk on Zoom
• Author(s) :
  • Putu Veri Swastika (Udayana University)
  • Sri Redjeki Pudjaprasetya (Bandung Institute of Technology)
  • Nugrahinggil Subasita (Center for Applied Climate Services, Climatological Department, Agency for Meteorology Climatology and Geophysics (BMKG))

[00848] Mathematical modelling of neuroblast migration in the mouse brain

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G710
• Type : Contributed Talk
• Abstract : This talk is devoted to the mathematical modeling of migration of neuroblasts, precursor cells of neurons, with PDE. The pathway is determined mainly by attraction forces and the heterogeneous mobility of neuroblasts in different regions of the brain. In numerical simulations, the application of novel discontinuous Galerkin methods allows to maintain the properties of the continuous model. We present some successful computer tests including parameter adjust to fit real data from rodent brains.
• Classification : 35Q92, 92-10, 65M60
• Format : Online Talk on Zoom
• Author(s) :
  • Noelia Ortega-Román (Universidad de Cádiz)
  • J. Rafael Rodríguez-Galván (Universidad de Cádiz)
  • Daniel Acosta-Soba (Universidad de Cádiz)
  • Francisco Guillén-González (Universidad de Sevilla)

[00849] Well-suited upwind DG scheme for a phase-field tumor model

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @G710
• Type : Contributed Talk
• Abstract : This talk is focused on the numerical analysis of a modified diffuse-interface tumor model with degenerate mobility. In particular, we develop a discontinuous Galerkin upwind scheme that conserves the mass, preserves the discrete maximum principle and satisfies an energy law both for the Cahn-Hilliard equation and for the phase-field tumor model. Moreover, we present several numerical experiments that enhance the qualitative behavior of the model and which are in accordance with the theoretical results.
• Classification : 35Q92, 65M60, 92-10
• Format : Online Talk on Zoom
• Author(s) :
  • Daniel Acosta-Soba (Universidad de Cádiz)
  • Francisco Guillén-González (Universidad de Sevilla)
  • J. Rafael Rodríguez-Galván (Universidad de Cádiz)

MS [00187] Analysis and geometry of inextensible materials

room : G801

• [02002] Modeling and Simulation of Thin Sheet Folding
  • Format : Talk at Waseda University
  • Author(s) :
    • Soeren Bartels (University of Freiburg)
  • Abstract : The folding of a thin elastic sheet along a curved arc has various applications including the construction of bistable devices. We discuss the derivation of a plate model from three-dimensional hyperelasticity and rigidity properties of admissible deformations and minimizers. The numerical solution is based on an isoparametric discontinuous Galerkin finite element method that provides a suitable geometric approximation of the folding arc. Error estimates are presented for a linearized version of the model problem.
• [02066] Periodic partitions with minimal perimeter
  • Format : Talk at Waseda University
  • Author(s) :
    • Matteo Novaga (University of Pisa)
    • Annalisa Cesaroni (University of Padova)
  • Abstract : I will discuss existence and regularity of fundamental domains which minimize a general perimeter functional in a homogeneous metric measure space. In the planar case I will give a detailed description of the domains which are minimal for a general anisotropic perimeter.
• [02439] Inextensible elastic curves and subriemannian maniflods
  • Format : Talk at Waseda University
  • Author(s) :
    • Chun-Chi Lin (National Taiwan Normal UniversiNational Taiwan Normal University)
  • Abstract : Elastic curves are relatively simple geometric objects in differential geometry but are related to many applications in image sciences and geometric control theory. These curves are characterized the equilibrium configurations to the energy functional, $$\int \, (a+b\cdot|\vec\kappa|^2) \, ds, $$ where $a, b$ are positive constants, $\vec\kappa$ is the curvature vector of curves and $s$ is the arclength of curves. The Euler-Lagrange equations are fourth-order differential equations of the curves. On the other hand, an energy decreasing flow of inextensible elastic curves in the plane can be formulated by a second-order parabolic equation with Lagrange multipliers. However, difficulties come out as one generalizes this approach to curves in higher dimensional Euclidean spaces or Riemannian manifolds. In this talk, we are interested in relating inextensible elastic curves to geometric analysis of curves in subriemannian manifolds. We will introduce a different approach for problem and demonstrate our progress and results.
• [02016] Gradient flows of inextensible networks
  • Format : Talk at Waseda University
  • Author(s) :
    • Dmitry Vorotnikov (Universidade de Coimbra )
  • Abstract : We address solvability of equations of overdamped motion of inextensible networks. Problems of this kind can be expressed as PDE that involve unknown Lagrange multipliers and non-standard boundary conditions related to the moving junctions. They can also be interpreted as gradient flows on certain ''manifolds'' of probability measures. We also discuss the geometry of these manifolds as well as links of our equations to the mean curvature flow and to fluid dynamics.

MS [02221] Recent progress on mathematical theory of boundary layer

room : G802

• [03513] Nonlinear Stability of the Taylor-Couette flow
  • Format : Talk at Waseda University
  • Author(s) :
    • Te Li (National University of Singapore)
  • Abstract : Hydrodynamic stability at high Reynolds number is a central topic in fluid mechanics. It is closely related to turbulence. Whereas the laminar velocity profile is linearly stable for all Reynolds number, Reynolds experiment reveals that laminar flows could be unstable and transit to turbulence at high Reynolds number. This phenomenon is described as subcritical transition. And the mechanism behind is not well understood yet. To investigate the dynamical nonlinear stability, we develop a systematic approach to establish sharp resolvent estimates for the linearized operator around the 2D Taylor-Couette flow. One of the main difficulties is that the linearized operator is non-self-adjoint. Based on the resolvent estimates, we first show the sharp enhanced-dissipation decay rate of the solution for the linearized system. We also derive the space-time estimates for the nonlinear part using the resolvent estimates. Combining all above, we obtain the nonlinear transition threshold for the Taylor-Couette flow. This talk is based on a series of joint works by X. An-T. He-L.
• [04401] On the solvability of the linearized Triple-Deck system
  • Format : Online Talk on Zoom
  • Author(s) :
    • Yasunori Maekawa (Kyoto University)
    • David Gerard-Varet (Universite Paris Cite et IMJ-PRG)
    • Sameer Iyer (University of California)
  • Abstract : We establish the solvability of the linearized Triple-Deck system in Gevrey $3/2$ regularity in the tangential variable, under the concavity assumptions on the background flow. This talk is based on the joint work with David Gerard-Varet (Universite Paris Cite et IMJ-PRG) and Sameer Iyer (University of California).
• [03016] On dynamic stability for steady Prandtl solutions
  • Format : Online Talk on Zoom
  • Author(s) :
    • Yue Wang (Capital Normal University)
  • Abstract : In this talk, I will first review some properties of steady Prandtl solutions. Then I will introduce our recent work on dynamic stability of steady Prandtl solutions( a joint work with Yan Guo and Zhifei Zhang) and others’ related results.

MS [00345] Recent Developments for High-frequency Waves and Tomography

room : G808

• [03696] Learning based on data and numerical solutions for differential equations
  • Format : Talk at Waseda University
  • Author(s) :
    • Jin Cheng (Professor)
    • Yu Chen (Dr.)
  • Abstract : Numerical methods for partial differential equations are the important and powerful tols for the engineering problems. The study of numerical methods for PDE is one of the hottest research topics in the applied mathematics and computational mathematics. Based on ideas from data learning, we propose a new method for finding numerical solutions of differential equations effectively, especially for the Helmholtz equations with the high wave numbers. The main idea of this method is to construct the approximation solutions by utilizing the relevant information from the solution we already have, which include the explicit solutions, the measured data from the experiments, the expression of the basic solution and the numerical solution obtained from the numerical experiments, etc. This is also a fast and high-precision numerical algorithm. It is shown that, especially for high-frequency problems, this method provides feasible solutions.
• [01633] Butterfly-compressed Hadamard-Babich Integrator for High-Frequency Helmholtz and Maxwell Equations in Inhomogeneous Media
  • Format : Talk at Waseda University
  • Author(s) :
    • Yang Liu (Lawrence Berkeley National Laboratory)
    • Jian Song (Michigan State University)
    • Robert Burridge (University of New Mexico)
    • Jianliang Qian (Michigan State University)
  • Abstract : We present a butterfly-compressed representation of the Hadamard-Babich (HB) ansatz for the Green's function of the high-frequency Helmholtz and Maxwell equations in smooth inhomogeneous media with arbitrary excitation sources. The proposed algorithm first solves the phase and HB coefficients via eikonal and transport equations using a coarse mesh, and then compresses the resulting HB interactions using several newly developed butterfly algorithms, leading to an optimal CPU complexity for any bounded 3D domains.
• [02074] Development and Analysis a higher-order numerical method for Helmholtz equation with high wave number
  • Format : Talk at Waseda University
  • Author(s) :
    • Wenyuan Liao (University of Calgary)
  • Abstract : Numerical solution of the Helmholtz equation with high wave numbers is a challenging task due to several reasons, such as the large size and indefiniteness of the discrete linear system. In this talk, we introduce a new iterative method which is motivated by the idea of the normal equation method. We then solve the equivalent positive definite normal equation. Combined with acceleration techniques, the new method is efficient and accurate for solving the Helmholtz equation.
• [02172] Fixed Angle Inverse Scattering For Velocity
  • Format : Talk at Waseda University
  • Author(s) :
    • Rakesh Rakesh (University of Delaware)
  • Abstract : An inhomogeneous acoustic medium is probed by a plane wave and the resultant time dependent wave is measured on the boundary of a ball enclosing the inhomogeneous part of the medium. We describe our partial results about the recovery of the velocity of the medium from the boundary measurement. This is a formally determined inverse problem for the wave equation, consisting of the recovery of a non-constant coefficient of the principal part of the operator from the boundary measurement.

MS [01996] Control and inverse problems on waves, oscillations and flows

room : G809

• [04229] Inverse problems for the Duffing equation in pediatrics
  • Format : Talk at Waseda University
  • Author(s) :
    • Manabu Machida (Hamamatsu University School of Medicine)
  • Abstract : The prognostic prediction of the neonatal hypoxic-ischemic encephalopathy (HIE) has been tried with near-infrared spectroscopy. In this talk, the Duffing equation is proposed as a model which governs the time-evolution of the cerebral blood volume. We will consider an inverse problem of determining coefficients and initial values of the equation.
• [04402] Unique determination of source and Robin coefficient in fractional diffusion equation
  • Format : Talk at Waseda University
  • Author(s) :
    • Zhiyuan Li (Ningbo University)
    • Daijun Jiang (Central Central China Normal UniversityChina Normal University)
  • Abstract : In this talk, we consider an inverse problem of simultaneously determining the spatially dependent source term and the Robin boundary coefficient in a time fractional diffusion equation, with the aid of extra measurement data at a subdomain near the accessible boundary. Firstly, the spatially varying source is uniquely determined in view of the unique continuation principle and Duhamel principle for the fractional diffusion equation. The Hopf lemma for a homogeneous time-fractional diffusion equation is proved and then used to prove the uniqueness of recovering the Robin boundary coefficient.
• [05327] Fine-tuning neural-operator architectures for training and generalization
  • Format : Talk at Waseda University
  • Author(s) :
    • Takashi Furuya (Shimane University)
  • Abstract : We investigate the generalization error of Neural Operators (NOs), which aim to approximate the forward operator in PDEs, and propose modifications of NOs, referred to as ${\textit{s}}{\text{NO}}+\varepsilon$. We establish generalization error bounds for both NOs and ${\textit{s}}{\text{NO}}+\varepsilon$, and we observe that our bound is sharper than that for NOs. Additionally, our experiments, particularly the wave equation experiment, demonstrate that our proposed network exhibits remarkable generalization capabilities, whereas NOs perform poorly in out-of-distribution scenarios.
• [03684] Reconstruction of location for a single point target in time-domain fluorescence diffuse optical tomography
  • Format : Talk at Waseda University
  • Author(s) :
    • Junyong Eom
    • Gen Nakamura (Hokkaido University)
    • Goro Nishimura (Hokkaido University)
    • Chunlong Sun (Nanjing University of Aeronautics and Astronautics)
  • Abstract : The time-domain fluorescence diffuse optical tomography (FDOT) problem is to recover the distribution of fluorophores in biological tissue from the time-domain measurement on the boundary. The measurement is conducted by several pairs (S-D pairs) of a point source and a point detector. In this paper, we identify the location of the distribution of fluorophores over a point, refer as a point target. We first express a solution for the forward problem in a dimensionless form and consider its asymptotic expansion. Then, we theoretically investigate the minimal number of S-D pairs to determine the point target location, analyzing the sensitivity matrix. Finally, we numerically verify the invertibility of the matrix and demonstrate the local solvability for locating well-separated multiple point targets.

MS [02499] Machine Learning for dynamics and its applications

room : F308

• [04040] Construction of differential equations from scalar chaotic time series
  • Format : Talk at Waseda University
  • Author(s) :
    • NATSUKI TSUTSUMI (Hitotsubashi University)
    • kengo nakai (Okayama University)
    • Yoshitaka Saiki (Hitotsubashi University)
  • Abstract : We propose a method of constructing a system of differential equations of chaotic behavior only from observable scalar time series. The method employs a regression using Gaussian radial basis functions together with polynomial terms. We apply it to several chaotic time series. The obtained model is assessed from the viewpoint of time series forecast, reconstruction of invariant sets, and invariant densities. Delay coordinate and a chaotic saddle have played a big role in the procedure.
• [04709] Data-driven inference of Navier-Stokes turbulence from limited observations
  • Format : Talk at Waseda University
  • Author(s) :
    • Masanobu Inubushi (Tokyo University of Science)
  • Abstract : Inference of turbulent states governed by the Navier-Stokes equations is one of the challenging and crucial problems for applied mathematics and industrial applications because of the high dimensionality and nonlinearity of fluid dynamics. In this study, we propose a data-driven inference method of turbulent dynamics from limited observations, which is suitable for industrial applications, and discuss its performance from the viewpoint of dynamical system theory.
• [03862] Long-lead prediction of Indian Summer Monsoon onset with reservoir computing
  • Format : Talk at Waseda University
  • Author(s) :
    • Takahito Mitsui (Technical University of Munich)
    • Niklas Boers (Technical University of Munich)
  • Abstract : Although the prediction of the Indian Summer Monsoon (ISM) onset is of crucial importance for water-resource management and agricultural planning on the Indian sub-continent, the long-term predictability, especially at seasonal time scales, is little explored. We propose a method based on reservoir computing that provides skilfull long-term forecasts of the ISM onset. Our study demonstrates that machine-learning-based approaches can be simultaneously helpful for both data-driven prediction and enhancing the process understanding of climate phenomena.

MS [01000] Advances in random dynamical systems and ergodic theory

room : F309

• [05540] Continuation of attractors of random dynamical systems with bounded noise
  • Format : Talk at Waseda University
  • Author(s) :
    • Jeroen Lamb (Imperial College London)
    • Martin Rasmussen (Imperial College London)
    • Konstantinos Kourliouros (Imperial College London)
    • Dmitry Turaev (Imperial College London)
    • Wei Hao Tey (IRCN, The University of Tokyo)
    • Kalle Timperi (Oulu University)
  • Abstract : We study the problem of persistence of minimal invariant sets with smooth boundary for a class of discrete-time set-valued dynamical systems, naturally arising in the context of random dynamical systems with bounded noise. In particular, we introduce a single-valued map, the so-called boundary map, which has the property that a certain class of invariant submanifolds for this map is in one-to-one correspondence with invariant sets for the corresponding set-valued map. We show that minimal invariant sets with smooth boundary persist under small perturbations of the set-valued map, provided that the associated boundary map is normally hyperbolic at the unit normal bundle of the boundary.
• [05055] Noise-induced chaos and conditioned Lyapunov exponents in a random logistic map
  • Format : Talk at Waseda University
  • Author(s) :
    • Bernat Bassols Cornudella (Imperial College London)
    • Jeroen SW Lamb (Imperial College London)
  • Abstract : We consider a random logistic map with bounded additive noise, in the parameter regime where the deterministic logistic map has a stable period three cycle. We demonstrate how the transition from noise-induced synchronisation (negative Lyapunov exponent) to noise-induced chaos (positive Lyapunov exponent), arising as a result of growing noise amplitude, can be understood through a two-compartment approximation, effectively modelling the competition between contracting and expanding behaviour. Relevant characteristic exit times and conditioned Lyapunov exponents for the predominantly contracting and expanding compartments are obtained through quasi-stationary and quasi-ergodic invariant measures.
• [01453] On the quasi-ergodicity of absorbing Markov chains with unbounded transition densities, including random logistic maps with escape
  • Format : Online Talk on Zoom
  • Author(s) :
    • Matheus Manzatto de Castro (Imperial College London)
    • Jeroen S. W. Lamb (Imperial College London)
    • Martin Rasmussen (Imperial College London)
    • Vincent P. H. Goverse (Imperial College London)
  • Abstract : In this paper, we consider absorbing Markov chains $X_n$ admitting a quasi-stationary measure $\mu$ on $M$ where the transition kernel $\mathcal{P}$ admits an eigenfunction $0 \leq \eta \in L^1(M,μ)$. We find conditions on the transition densities of $\mathcal{P}$ with respect to $\mu$, which ensure that $\eta(x) \mu(\mathrm{d} x)$ is a quasi-ergodic measure for $X_n$ and that the Yaglom limit converges to the quasi-stationary measure μ-almost surely. We apply this result to the random logistic map $X_{n+1}=\omega_n X_n(1−X_n)$ absorbed at $\mathrm{R}\setminus [0,1]$, where $\omega_n$ is an i.i.d sequence of random variables uniformly distributed in $[a,b]$, for $1\leq a < 4$ and $b>4.$

MS [02025] Recent Advances on the Analysis and Applications of Continuous and Discrete Integrable Systems

room : F310

• [03558] Integrable boundary conditions for quad-graph systems: classification and applications
  • Format : Talk at Waseda University
  • Author(s) :
    • Cheng Zhang (Shanghai University)
  • Abstract : The notion of boundary conditions for quad-graph systems will first be introduced. The boundary conditions are naturally defined on triangles that arise as dualization of given quad-graphs with boundary. For three-dimensionally consistent quad-graph systems, the so-called integrable boundary conditions will be characterized as boundary conditions satisfying the boundary consistency condition that is a consistency condition defined on a half of a rhombic-dodecahedron. Based on these notions, three main results will then be presented: a classification of integrable boundary conditions for quad-equations of the ABS classification; Lax formulations of integrable boundary conditions; and the so-called open boundary reduction technique as systematic a means to construct integrable mappings from integrable initial-boundary value problems for quad-graph systems.
• [03221] Geometric Aspects of Miura Transformations
  • Format : Talk at Waseda University
  • Author(s) :
    • Changzheng Qu (Ningbo University)
    • Zhiwei Wu (Sun Yat-sen University)
  • Abstract : The Miura transformation and its extensions play a crucial role in the study of integrable systems, which have been used to relate different kinds of integrable equations and to classify the bi-Hamiltonian structures. In this talk, we will discuss the geometric aspects of the Miura transformation. The generalized Miura transformations from the mKdV-type hierarchies to the KdV-type hierarchies are constructed under both algebraic and geometric settings. We show that the Miura transformations not only relate integrable curve flows in different geometries but also induce the transition between different moving frames. Moreover, the Miura transformation gives the factorization of generating operators of constraint Gelfand-Dickey hierarchy. This talk is based on a recent joint work with Prof. Qu, Changzheng.
• [04193] Curvature equation with conic singularities and integrable system
  • Format : Talk at Waseda University
  • Author(s) :
    • Ting-Jung Kuo (National Taiwan Normal University)
  • Abstract : Let $\left( E_{\tau },dz^{2}\right) $, $\tau \in \mathbb{H}$ be a flat torus. We consider the follwing PDE: \begin{equation} \Delta u+e^{u}=\sum_{j=1}^{N}4\pi \alpha _{j}\delta _{p_{j}}\text{ on } E_{\tau } ~~~~~(1) \end{equation} where $\delta _{p_{j}}$ is the dirac measure and $\alpha _{j}>-1$. In the literature, equation (1) arised from conformal geometry. Indeed, (1) is equivalent to saying that the conformal metric $ds^{2}=\frac{1}{2 }e^{u}\left\vert dz\right\vert ^{2}$ with conic singularties at $p_{j}$ has the Gaussian curvature $1$. By classical Liouville theorem, the curvature equation is also an integrable system which yields a complex ODE (a generalization of the classical Lame equation ) and the solvability of equation (1) is equivalent to saying that the corresponding complex ODE is always apparent and has unitary monodromy. The study of the monodromy of a general complex ODE is difficult in general. However, recently, we also discover its relation with KdV theory. In this talk, I will talk about this deep connection and focus on the study of the complex ODE from monodromy point of view.
• [03194] A Generalization of an Integrability Theorem of Darboux and the Stable Configuration Condition.
  • Format : Talk at Waseda University
  • Author(s) :
    • Irina A. Kogan (North Carolina State University)
  • Abstract : In his monograph "Systemes Orthogonaux" (1910), Darboux stated three theorems providing local existence and uniqueness of solutions to first order systems of PDEs, where for each unknown function a certain subset of partial derivatives is prescribed and the values of the unknown functions are prescribed along transversal coordinate affine subspaces. The more general of the theorems, Theorem III, was proved by Darboux only for the cases of 2 and 3 independent variables. We formulate and prove a generalization of Theorem III. Instead of partial derivatives, we prescribe derivatives of the unknown functions along vector fields. The values of the unknown functions are prescribed along arbitrary transversal submanifolds. We identify a certain Stable Configuration Condition (SCC). This is a geometric condition that depends on both the set of vector fields and on the initial manifolds. SCC is automatically met in the case considered by Darboux. Assuming the SCC and the relevant integrability conditions are satisfied, we establish local existence and uniqueness of a $C^1$-smooth solution via Picard iteration for any number of independent variables. If the SCC is not satisfied, we show on a concrete example that the uniqueness can fail the following strong sense: for the same initial data, there are two solutions that differ on any open subset of their domains. This talk is based on joint publications with Michael Benfield and Kris Jenssen.

contributed talk: CT062

room : F311

[00335] Fractional Relaxation-Oscillation and Fractional Biological Population Equations: Applications of the Elzaki Decomposition Method

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @F311
• Type : Contributed Talk
• Abstract : In various suitable habitat scenarios, the Elzaki decomposition method is used to handle the fractional order relaxation and damped oscillation equation along with the time-fractional spatial diffusion biological population model. According to the graphs for the found solutions, fractional relaxation is a super-slow phenomenon due to its protracted descent, and fractional damped oscillation is an intermediate process that explains damped oscillation dynamic systems generated by some attenuated oscillations. The biological population model of time-fractional spatial diffusion portrays a rapid increase in population density in an ecosystem migrating from an unfavourable zone to a good habitat.
• Classification : 26A33, 33E12, 35A22, 34C26, 60J70
• Format : Online Talk on Zoom
• Author(s) :
  • Daya Lal Suthar (Wollo University)

[00724] Applicability to information engineering using the Sato’s hyperfunction

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @F311
• Type : Contributed Talk
• Abstract : Wavelet transform and discrete image processing are one of the important subjects in the field of information engineering. However, although the use of the generalised function in Fourier transform is possible, it is difficult to apply to wavelet transform by using the generalised function. On the other hand, the delta function is mainly used in discrete image analysis. In this study, we have considered their applicability using the Sato’s hyperfunction.
• Classification : 46F15, 32A45, 65T60, 65D18, 46T30
• Format : Talk at Waseda University
• Author(s) :
  • HIROSHI MURAYAMA
  • HIROSHI MURAYAMA (Graduate School of Science and Engineering, SOKA University)
  • Yoshio ISHII (Faculty of Science and Engineering, SOKA University)

[00884] Time-Frequency Analysis of Functional Datasets

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @F311
• Type : Contributed Talk
• Abstract : We introduce an operator valued Short-Time Fourier Transform for certain classes of operators with operator window, and show that the transform acts in an analogous way to the STFT for functions. This object reflects the time-frequency behaviour for datasets of functional data in both a intra- and inter-functional manner, showing the function-wise time-frequency distribution and cross correlation of time-frequency concentration between datapoints, hence combining desirable aspects of existing basis selection methods for functional data science.
• Classification : 46-XX, 62R10
• Format : Talk at Waseda University
• Author(s) :
  • Monika Dörfler (University of Vienna)
  • Franz Luef (Norwegian University of Science and Technology (NTNU))
  • Henry McNulty (Norwegian University of Science and Technology (NTNU))
  • Eirik Skrettingland (NA)

[02369] Unique continuation results for generalized ray transforms

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @F311
• Type : Contributed Talk
• Abstract : We discuss unique continuation results for certain generalized ray transforms. We prove that if the generalized ray transform of a function vanishes along all lines passing through an open set in Euclidean space, and the function vanishes in that same open set, then the function vanishes identically. We give an example to show that the second assumption cannot be removed. We also consider generalized transforms on higher order objects such as vector fields, symmetric 2-tensor fields etc., and under the same hypotheses, show that a certain component vanishes. Since such ray transforms have a non-trivial kernel, this is the optimal result that one can expect.
• Classification : 46F12, 35J40, 45Q05
• Format : Talk at Waseda University
• Author(s) :
  • Divyansh Agrawal (TIFR Centre for Applicable Mathematics (CAM))
  • Venkateswaran P. Krishnan (TIFR Centre for Applicable Mathematics (CAM))
  • Suman Kumar Sahoo (University of Jyvaskyla)

[02534] Solving a Tree Genetic Diversity Via Homogeneous Self Dual Embedding

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @F311
• Type : Industrial Contributed Talk
• Abstract : This research discusses another way to solve Second-Order Cone Programming of a tree genetic diversity. We propose a method based on a splitting augmented Lagrangian method (SALM) and an implementation of a homogenous self-dual (HSD) concept to a sub-problem that belongs to convex programming. Furthermore, we utilize operator splitting to review the existence of HSD. An optimal solution for tree genetic diversity can be obtained by using the modified SALM.
• Classification : 46N10, 47N10, 90C26, 35Q49, 97M40
• Format : Online Talk on Zoom
• Author(s) :
  • Alvian Alif Hidayatullah (Sepuluh Nopember Institute of Technology)
  • Sena Safarina (Sepuluh Nopember Institute of Technology)
  • Subchan Subchan (Sepuluh Nopember Institute of Technology)

contributed talk: CT065

room : F312

[00329] A-posteriori error estimates for parabolic optimal control problems with controls acting on lower dimensional manifolds

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @F312
• Type : Contributed Talk
• Abstract : In this talk, we shall present a-posteriori error estimates for the fully discrete finite element approximation to the optimal control problem governed by parabolic partial differential equations where the control is acting on lower dimensional manifolds. We use piecewise linear and continuous finite elements for the approximations of state and adjoint variables whereas piecewise constant functions are employed to approximate the control variable. Moreover, the time derivative is approximated by using the backward Euler scheme. We derive a-posteriori error estimates for the various dimensions of the manifold. Numerical results reveal the effectiveness of the error estimators.
• Classification : 49J20, 49K20, 65N15, 65N30
• Format : Talk at Waseda University
• Author(s) :
  • Rajen Kumar Sinha (Indian Institute of Technology Guwahati)
  • Ram Manohar (Indian Institute of Technology Kanpur)

[01805] A priori error estimates for parabolic interface problems with measure data

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @F312
• Type : Contributed Talk
• Abstract : This talk aims to present a priori error analysis for linear parabolic interface problems with measure data in time in a bounded convex polygonal domain in $R^2$. Both the spatially discrete and the fully discrete approximations are analyzed. Due to the low regularity of the solution, the convergence analysis of such problems become challenging. A priori error bounds in the $L^2(L^2(\Omega))$-norm for both the spatially discrete and the fully discrete schemes are derived under the minimal regularity assumption the solution together with the $L^2$-projection operator and the duality argument. Numerical results are reported to support the theoretical analysis.
• Classification : 49J20, 49K20, 65N15, 65N30
• Format : Talk at Waseda University
• Author(s) :
  • Jhuma Sen Gupta (BITS Pilani Hyderabad)

[02035] General double-sided orthogonal planes split QFT and wavelet transform on functions and distribution spaces

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @F312
• Type : Contributed Talk
• Abstract : We present, in our talk, an alternative version of the convolution and duality formula, and we give some results on functions and distribution spaces for the general double-sided orthogonal planes split quaternion Fourier transform. We provide the discrete representation of Z2−periodic function for continuous quaternion Wavelet transform. Finally, we prove the Plancherel and inversion formulas for the continuous General double-sided orthogonal 2D−planes split quaternionic Wavelet transform.
• Classification : 42C40, 42B10, 14D21
• Format : Online Talk on Zoom
• Author(s) :
  • Hakim Monaim (Moulay Ismail University)

[01114] Modeling Covid-19 Cases and Vaccination Interplay through Time-Varying Copula Approach

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @F312
• Type : Contributed Talk
• Abstract : Currently, the Indonesian government has made various efforts to reduce the number of Covid-19 cases, one of which is through administering vaccines. This study aims to model the interplay between the number of Covid-19 cases and the number of citizens who have been vaccinated, especially in term of the temporal relationship, using the time-varying copula approach.
• Classification : 60Exx, 62Hxx, 62Pxx, Multivariate Modeling, Copula Modeling
• Format : Online Talk on Zoom
• Author(s) :
  • Atina Ahdika (Universitas Islam Indonesia)

[02225] On Fractional Lah-Bell Polynomials and Numbers

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @F312
• Type : Contributed Talk
• Abstract : In this talk, we will present a fractional generalization of the Lah-Bell polynomials and the Lah numbers associated to the fractional Poisson probability distribution. We derive the exponential generating functions in terms of the Mittag-Leffler function along with some convolution identities. These identities are the natural extension of several well-known identities available in literature. Finally, applications to compound Poisson process, Mittag-Leffler function, and the Laguerre polynomials are also presented.
• Classification : 60E05, 05A19, 26A33, 11C08, 05A17
• Format : Online Talk on Zoom
• Author(s) :
  • Ritik Soni (Central University of Punjab)
  • Ashok Kumar Pathak (Central University of Punjab)

MS [00356] Recent progress in variational problems with nonlocality

room : F401

• [03768] Nonlocal capillarity theory
  • Format : Online Talk on Zoom
  • Author(s) :
    • Enrico Valdinoci (University of Western Australia)
  • Abstract : We describe some recent results motivated by a nonlocal theory of capillarity, as related to the formation of droplets due to long-range interaction potentials. We will discuss the notion of contact angle in this setting, considering a nonlocal version of the classical Young's Law, together with some regularity and asymptotic properties.
• [03751] Skyrmion theory in magnetic thin films: the role of non-local magnetic dipolar interaction
  • Format : Talk at Waseda University
  • Author(s) :
    • Anne Bernand-Mantel
    • Cyrill Muratov (University of Pisa)
    • Theresa Simon (Muenster University)
    • Valeriy Slastikov (Bristol University)
  • Abstract : Compact magnetic skyrmion are potential bit-encoding states for spintronic memory and logic applications that have been the subject of a rapidly growing number of studies in recent years. We will present our recent work where we used rigorous mathematical analysis to develop a skyrmion theory that takes into account the full dipolar energy in the thin film regime and provides analytical formulas for compact skyrmion radius, rotation angle and energy.
• [05516] Normalized solutions and limit profiles of the Gross-Pitaevskii-Poisson equation
  • Format : Online Talk on Zoom
  • Author(s) :
    • Vitaly Moroz (Swansea University)
  • Abstract : Gross-Pitaevskii-Poisson (GPP) equation is a nonlocal modification of the Gross-Pitaevskii equation with an attractive Coulomb-like term. It appears in the models of self-gravitating Bose-Einstein condensates proposed in cosmology and astrophysics to describe Cold Dark Matter and Boson Stars. We investigate the existence of prescribed mass (normalised) solutions to the GPP equation, paying special attention to the shape and asymptotic behaviour of the associated mass-energy relation curves and to the limit profiles of solutions at the endpoints of these curves. In particular, we show that after appropriate rescalings, the constructed normalized solutions converge either to a ground state of the Choquard equation, or to a compactly supported radial ground state of the integral Thomas-Fermi equation. In different regimes the constructed solutions include global minima, local but not global minima and unstable mountain-pass type solutions. This is a joint work with Riccardo Molle and Giuseppe Riey.
• [04003] A distributional approach to nonlocal curvature motions
  • Format : Online Talk on Zoom
  • Author(s) :
    • Massimiliano Morini (University of Parma)
  • Abstract : After reviewing the new distributional approach recently developed to provide a well-posed formulation of the crystalline mean curvature flow, we show how to extend it to some nonlocal motions. Applications include the fractional mean curvature flow and the Minkowski flow; i.e., the geometric flow generated by the (n-1)-dimensional Minkowski pre-content. This is a work in collaboration with F. Cagnettti (University of Sussex) and D. Reggiani (Scuola Superiore Meridionale).

MS [00802] Numerical Algorithms for the Eikonal Equation and Its Applications

room : F402

• [03535] Variational methods for distance function approximation and applications
  • Format : Talk at Waseda University
  • Author(s) :
    • Pierre-Alain Fayolle (University of Aizu)
    • Alexander Belyaev (Heriot-Watt University)
  • Abstract : The distance function (signed or unsigned) to the boundary (curve or surface) of a given geometric domain is a useful tool in geometry processing, shape and solid modeling, as well as other related domains. It has various applications in several fields including surface reconstruction from scattered data, meshing, shape interrogation, computational fluid dynamics (turbulence modeling), computational mechanics, and robot path planning. In this talk, I will focus on several recent variational methods for computing the distance function or its approximation. Efficient numerical algorithms corresponding to these methods will also be discussed.
• [02323] Solving the eikonal equation utilizing mimetic methods
  • Format : Talk at Waseda University
  • Author(s) :
    • Miguel Dumett (San Diego State University)
  • Abstract : The Eikonal equation with Soner boundary conditions is solved utilizing high-order mimetic differences. Mimetic difference methods construct PDE discrete analogs. These preserve vector calculus identities as well as its integral theorems while keeping constant order of accuracy over the whole grid, including the boundary. The proposed algorithm leverages on the Fast Marching method and resembles a quasi-Newton iterative scheme.
• [03845] Jet marching on unstructured meshes: algorithms and applications
  • Format : Talk at Waseda University
  • Author(s) :
    • Samuel F Potter (Courant Institute of Mathematical Sciences)
  • Abstract : The jet marching method (JMM) solves the eikonal equation by marching its jet using semi-Lagrangian updates (i.e., local raytracing). Marching jets enables a compact Hermite interpolation-based scheme, enabling the use of paraxial raytracing for marching the amplitude of the associated geometric optic wave. We use the JMM to solve high-frequency wave problems on unstructured meshes, with applications motivated by computational room acoustics and light transport in miniwasp ommatidia.
• [03445] Regularized eikonal equation on polyhedral meshes
  • Format : Talk at Waseda University
  • Author(s) :
    • Jooyoung Hahn (Slovak University of Technology in Bratislava)
    • Karol Mikula (Slovak University of Technology in Bratislava)
    • Peter Frolkovič (Slovak University of Technology in Bratislava)
  • Abstract : A cell-centered finite volume method (FVM) is discussed to compute a distance from objects on a 3D computational domain discretized by polyhedral cells. Time-relaxed and Laplacian-regularized eikonal equations are compared numerically and we show how the Soner boundary condition is straightforwardly combined in a conventional FVM code. The Laplacian regularization is more practical for large numbers of cells or distant regions of interest. Additionally, the algorithms can be implemented with parallel computing using domain decomposition.

MS [00747] Analysis and Numerics on Deep Learning Based Methods for Solving PDEs

room : F403

• [02903] Deep adaptive sampling for numerical PDEs
  • Author(s) :
    • Tao Zhou (Chinese Academy of Sciences)
  • Abstract : Physics-informed neural networks (PINNs) have emerged as an effective technique for solving PDEs in a wide range of domains. It is noticed, however, the performance of PINNs can vary dramatically with different sampling procedures. For instance, a fixed set of (prior chosen) training points may fail to capture the effective solution region (especially for problems with singularities). To overcome this issue, we present in this work an adaptive strategy, termed the failure-informed PINNs (FI-PINNs), which is inspired by the viewpoint of reliability analysis. The key idea is to define an effective failure probability based on the residual, and then, with the aim of placing more samples in the failure region, the FI-PINNs employs a failure-informed enrichment technique to adaptively add new collocation points to the training set, such that the numerical accuracy is dramatically improved. In short, similar as adaptive finite element methods, the proposed FI-PINNs adopts the failure probability as the posterior error indicator to generate new training points. We prove rigorous error bounds of FI-PINNs and illustrate its performance through several problems.
• [03007] Deep Learning for PDEs: Domain Decomposition and Adaptivity
  • Author(s) :
    • Qifeng Liao (ShanghaiTech University)
  • Abstract : Deep learning methods currently gain a lot of interest for solving partial differential equations (PDEs). However, significant challenges still exist for these new methods to achieve high accuracy, which include properly defining loss functions and choosing effective collocation points and network structures. In our work, we propose domain decomposition and adaptive procedures to improve the accuracy and efficiency of deep learning based methods.
• [03091] Bridging Traditional and Machine Learning-based Algorithms for Solving PDEs: The Random Feature Method
  • Author(s) :
    • JINGRUN CHEN (University of Science and Technology of China)
    • XURONG CHI (University ofUniversity of Science and Technology of China Science and Technology of China)
    • WEINAN E (AI for Science Institute, Beijing and Center for Machine Learning Research and School of Mathematical Sciences, Peking University)
    • ZHOUWANG YANG (School of Mathematical Sciences, University of Science and Technology of China)
  • Abstract : One of the oldest and most studied subject in scientific computing is algorithms for solving partial differential equations (PDEs). A long list of numerical methods have been proposed and successfully used for various applications. In recent years, deep learning methods have shown their superiority for highdimensional PDEs where traditional methods fail. However, for low dimensional problems, it remains unclear whether these methods have a real advantage over traditional algorithms as a direct solver. In this work, we propose the random feature method (RFM) for solving PDEs, a natural bridge between traditional and machine learning-based algorithms. RFM is based on a combination of well-known ideas: 1. representation of the approximate solution using random feature functions; 2. collocation method to take care of the PDE; 3. penalty method to treat the boundary conditions, which allows us to treat the boundary condition and the PDE in the same footing. We find it crucial to add several additional components including multi-scale representatio and adaptive weight rescaling in the loss function. We demonstrate that the method exhibits spectral accuracy and can compete with traditional solvers in terms of both accuracy and efficiency. In addition, we find that RFM is particularly suited for problems with complex geometry, where both traditional and machine learning-based algorithms encounter difficulties.
• [03011] On deep learning techniques for solving convection-dominated convection-diffusion equations
  • Author(s) :
    • Derk Frerichs-Mihov (Weierstrass Institute for Applied Analysis and Stochastics)
    • Linus Henning (Free University of Berlin)
    • Derk Frerichs-Mihov (Weierstrass Institute for Applied Analysis and Stochastics / Free University of Berlin)
  • Abstract : Convection-diffusion equations model the distribution of a scalar quantity in fluids, e.g., the concentration of drugs in blood. Many classical numerical methods produce unphysical values in practical applications when convection is much stronger than diffusion \([1,2]\). In the last decades, the popularity of deep learning methods has risen sharply due to many success stories, e.g., \([3,4]\). This talk brings together deep learning techniques and convection-diffusion equations. It shows challenges and proposes solutions to overcome them. \([1]\) Augustin, M., Caiazzo, A., John, V. et al. An assessment of discretizations for convection-dominated convection-diffusion equations. Computer Methods in Applied Mechanics and Engineering, 200(47- 48), pp. 3395–3409, 2011, https://www.doi.org/10.1016/j.cma.2011.08.012 \([2]\) Frerichs, D. and John, V. On reducing spurious oscillations in discontinuous Galerkin (DG) methods for steady-state convection-diffusion equations. Journal of Computational and Applied Mathematics, 393, pp. 113487/1–113487/20, 2021, https://www.doi.org/10.1016/j.cam.2021.113487 \([3]\) Raissi, M., Perdikaris, P. and Karniadakis, G. E. Physics Informed Deep Learning (Part I): Data-driven Solutions of Nonlinear Partial Differential Equations. ArXiv, arXiv:1711.10561v1, 2017, https://www.doi.org/10.48550/arXiv.1711.10561 \([4]\) Karniadakis, G. E., Kevrekidis, I. G., Lu, L. et al. Physics-informed machine learning. Nature Reviews Physics, 3, pp. 422440, 2021, https://www.doi.org/10.1038/s42254-021-00314-5

MS [00384] Origami Engineering (1/2)

room : F411

• [01536] Refoldability between polyhedra
  • Format : Talk at Waseda University
  • Author(s) :
    • Tonan Kamata (Japan Advanced Institute of Science and Technology)
  • Abstract : Refolding is an operation of reshaping a polyhedron into a polyhedron by cutting open the surface of the original one and folding the resulting unfolding to make the other one. Refolding is a natural subject with applications in space engineering, design engineering, and bioinformatics, but the known result is not so much. In this talk, we will present design methods of refolding for some specific classes of polyhedra and the possibility of reconfiguration by refoldings.
• [05407] Optimal Simple Fold-and-Cut of a Polygonal Line
  • Format : Talk at Waseda University
  • Author(s) :
    • Ryuhei Uehara (Japan Advanced Institute of Science and Technology)
  • Abstract : We investigate a natural variant of the fold-and-cut problem. We are given a long paper strip P and a polygonal line, which consists of a sequence of line segments, drawn on P. We cut all the line segments by one complete straight cut after overlapping all of them by a sequence of simple foldings. Our goal is to minimize the number of simple foldings to do that. When the polygonal line satisfies some certain geometric conditions, we can find a shortest sequence of simple foldings for the given polygonal line that consists of n line segments in O(n^3) time and O(n^2) space.
• [02335] Geometrical Comparison of Two kinds of Pairing Origami Polyhedron and Their Application to Beverage Containers
  • Format : Online Talk on Zoom
  • Author(s) :
    • Aya Abe (Meiji University)
    • Yang Yang (Meiji University)
    • Chie Nara (Meiji University)
    • Ichiro Hagiwara (Meiji University)
  • Abstract : Tachi-Miura Polyhedron is gaining attention as a 3-dimensional version of Miura-Ori. Meanwhile, Nojima Polyhedron is similar as TMP in that it can be folded both in the axial and radial direction. In this study, whether both are rigid folding or not is geometrically confirmed, and quantitatively considered how it affects the energy absorption properties. As a result, it effects the deformation modes but does not affect the purpose of investigating the feasibility of industrialization.

MS [00686] Higher-order networks for complex systems

room : F412

• [02953] Towards mixed volumes of binomial reaction networks
  • Format : Online Talk on Zoom
  • Author(s) :
    • Jane Ivy Coons (University of Oxford)
    • Mark Curiel (University of Hawai'i)
    • Elizabeth Gross (University of Hawai'i)
  • Abstract : Mass action kinetics on a chemical reaction network give rise to a polynomial system of equations. The zeros of this system are the steady states of the network, and its mixed volume is an upper bound on the number of complex steady states. We show that when the steady state ideal is binomial and the conservation laws satisfy a "partitionability" property, the mixed volume can be easily computed as a determinant.
• [02968] A Hypergraph Model of Opinion Dynamics
  • Format : Online Talk on Zoom
  • Author(s) :
    • Abigail Hickok (UCLA)
    • Yacoub Kureh (Industry)
    • Heather Zinn Brooks (Harvey Mudd College)
    • Michelle Feng (Caltech)
    • Mason A. Porter (UCLA)
  • Abstract : Networks encode only pairwise interactions and cannot take into account polyadic interactions. I’ll discuss how the incorporation of polyadic interactions (encoded by a hypergraph) changes the qualitative behavior of an opinion dynamics model, which is a model of how people’s opinions change with time as they interact. We show that our hypergraph model converges to consensus under a wide range of initial conditions, whereas network models converge to polarization under the same initial conditions.
• [02963] Topological techniques for classification of agent-based tumour-immune model
  • Format : Talk at Waseda University
  • Author(s) :
    • Gillian Grindstaff (University of California, Los Angeles)
    • Jingjie Yang (University of Oxford)
    • Hai Fang (University of Oxford)
    • Jagdeep Dhesi (University of Oxford)
    • Hee Rhang Yoon (Wesleyan University)
    • Joshua A. Bull (University of Oxford)
    • Helen M. Byrne (University of Oxford)
    • Heather A. Harrington (University of Oxford)
  • Abstract : We address the problem of classifying time series of synthetic 2-d spatial data from an agent-based model of tumour growth that includes tumour cells, macrophages, and blood vessels. We implement and compare the predictive power of four topological vectorizations specialized to such cell data: persistence images of Vietoris-Rips and radial filtrations at static time points, and persistence images for zigzag filtrations and persistence vineyards varying in time.
• [02931] Topological methods for spatial data in molecular biology
  • Format : Talk at Waseda University
  • Author(s) :
    • Katherine Benjamin (University of Oxford)
  • Abstract : Single-parameter persistent homology – the flagship tool in topological data analysis – has witnessed a wide range of successful applications in the biological sciences over the last decade. Multiparameter persistent homology is a natural generalisation allowing for higher-order analysis of more complex phenomena including time-varying data. In this talk, we demonstrate some applications of multiparameter persistent homology to spatial data in biology.

MS [01058] Recent advances in stochastic nonlinear dynamics: modeling, data analysis

room : E502

• [02092] Homogenization of the two dimensional singular polymer measure
  • Format : Online Talk on Zoom
  • Author(s) :
    • Huanyu Yang (Free University of Berlin)
  • Abstract : We consider the SDE on $[0,n]$: \begin{equation} \left\{ \begin{aligned} dZ^n_t&=\nabla h(n-t,Z^n_t)dt+dB_t,\\ Z_0^n&=x, \end{aligned} \right. \end{equation} where $B$ is the standard Brownian motion and $h$ is the solution to KPZ equation driven by space-white noise $\xi$ on $\mathbb{T}^2$. The law of $Z^n$ is the same as the law of the coordinate process under the sigular polymer measure $Q^n$ constructed by Cannizzaro and Chouk: \begin{equation} Q^n(d\omega)=\frac{1}{U(n)}\exp\left(\int_0^n\left(\xi\left(\omega\left(s\right)\right)-\infty\right)\right)\mathbb{W}(d\omega), \end{equation} where $\mathbb{W}$ is the Wiener measure on $C([0,\infty),\mathbb{R})$. By decomposing the drift term $h$ into a singular time-homogenious term and a smooth time-dependent term, we prove that $\left(\frac{1}{\sqrt{n}}Z^n_{nt}\right)_{t\in[0,1]}$ converges to a Brownian motion. This is the joint work with Nicolas Perkowski.

MS [01858] Interplay among Manifold Learning, Stochastic Calculus, and Volatility Estimation

room : E503

• [02761] On excursions inside an excursion
  • Format : Talk at Waseda University
  • Author(s) :
    • Ju-Yi Yen (University of Cincinnati)
  • Abstract : The distribution of ranked heights of excursions of a Brownian bridge is given by Pitman and Yor in $[1]$. In this work, we consider excursions of a Brownian excursion above a random level $x$, where $x$ is the value of the excursion at an independent uniform time on $[0,1]$. We analyze the maximum heights of these excursions as Pitman and Yor did for excursions of a Brownian bridge. $[1]$ J. Pitman and M. Yor. On the distribution of ranked heights of excursions of a Brownian bridge. Ann. Probab., 29(1):361–384, 2001.
• [02842] Diffusion Estimation with Fourier-Malliavin Method
  • Format : Talk at Waseda University
  • Author(s) :
    • Takatoshi Hirano
    • Jiro Akahori (Ritsumeikan university)
    • Simona Sanfelici (Parma university)
  • Abstract : In this talk, the estimation of the diffusion coefficient of the solution to a stochastic differential equation using Fourier estimation method proposed by P. Malliavin and M.E. Mancino is discussed.
• [02849] Statistical Analysis with Geodesics and Curvature in Data Space
  • Format : Talk at Waseda University
  • Author(s) :
    • Kei Kobayashi (Keio University)
    • Henry P. Wynn (London School of Economics)
  • Abstract : We proposed a method to perform data analysis after two types of metric transformation of the data space. The first transformation is based on the powered density integration and can be implemented approximately using an empirical graph. The second transformation corresponds to computing the extrinsic distance after embedding the data space into a metric cone. We proved both transformations monotonically change the curvature of the data space, but in different ways.

contributed talk: CT083

room : E504

[01435] Automatic generation of terrain maps using sequences of satellite images

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E504
• Type : Contributed Talk
• Abstract : In this work, we propose an unsupervised methodology for analyzing temporal sequences of satellite images. Images decompose into disjoint tiles, and we embed sequences of tiles into multidimensional time series. The proposed embedding captures valuable information about the terrain and its evolution. It allows the partitioning of the ground into different types of terrain and understanding of the relationship between them. The proposed methodology shows promising results when analyzing a region of Navarre, Spain.
• Classification : 62H35
• Format : Talk at Waseda University
• Author(s) :
  • Aritz Pérez (Basque Center for Applied Mathematics)
  • Carlos Echegoyen (Public University of Navarre)
  • Guzmán Santafé (Public University of Navarre)
  • Unai Pérez (Public University of Navarre)
  • María Dolores Ugarte (Public University of Navarre)

[02606] Modeling Indonesian Government Bond Yield Curve during Covid-19 Pandemic Time

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E504
• Type : Contributed Talk
• Abstract : Yield curve in bond investment will provide visualization of yields of bond as the function of the time to maturities. In this study, we analyze Indonesian Government Yield Curve (IGYSC) during the pandemic Covid-19. We apply the Nelson Siegel (NS) class model and compare the performance of the optimization method of based on numerical optimization and based on heuristic optimization. All the computation are done using R software.
• Classification : 62J02, 62P05, 65K05, 68W50, 90C20
• Format : Talk at Waseda University
• Author(s) :
  • Dedi Rosadi (Universitas Gadjah Mada)
  • Dinda Awanda Ramadhani (Universitas Gadjah Mada)
  • Agus Sihabuddin (Universitas Gadjah Mada)

[02336] Within-Groups Generalized M-Estimators in One-Way Unbalanced Panel Data Model

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E504
• Type : Industrial Contributed Talk
• Abstract : Within-Groups Generalized M-Estimators (WGM) is a method for determining robust estimators of outliers for panel data models. This study will conduct a simulation to compare WGM in one-way unbalanced panel data model with fixed-effects approach using different multivariate locations and scale estimators, namely S-multivariate, Minimum Volume Ellipsoid (MVE), and Minimum Covariance Determinant (MCD). Then apply it to economic growth data in Kalimantan. Based on the simulation results and applications, it is known that the WGM with the S-multivariate estimator gives a better MSE value.
• Classification : 62J99
• Format : Talk at Waseda University
• Author(s) :
  • Desi Yuniarti (Department of Mathematics, Faculty of Mathematics and Natural Science, Universitas Gadjah Mada, Yogyakarta)
  • Dedi Rosadi (Department of Mathematics, Faculty of Mathematics and Natural Science, Universitas Gadjah Mada, Yogyakarta)
  • Abdurakhman Abdurakhman (Department of Mathematics, Faculty of Mathematics and Natural Science, Universitas Gadjah Mada, Yogyakarta)

[02442] Geopolitical and Demographic Possible Factor affecting COVID-19 Spread level with OPLSDA approach

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E504
• Type : Industrial Contributed Talk
• Abstract : COVID-19 continuing challenges to health and socio-economic crisis. Geopolitical and demographic may possible affecting COVID-19 spread and this research focus on COVID-19 spread level classification. The method used is Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA), OPLS-DA projects predictor that have the best correlation with responses so that they can separate predictor variables from variables that are not correlated. OPLS-DA effectively identifies sources of variability between classes to produce good classification results with an accuracy rate 84.44%. The results also explain how predictor variables can affect the level of spread of COVID-19.
• Classification : 62H30, 68U01, Classification and Discriminant Analysis for Outlier and High-dimensional data
• Format : Online Talk on Zoom
• Author(s) :
  • Noviana Pratiwi (Gadjah Mada University)
  • Dedi Rosadi (Gadjah Mada University)
  • Abdurakhman Abdurakhman (Gadjah Mada University)

contributed talk: CT086

room : E505

[02093] British Call Option On Stocks under Stochastic Interest Rate

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E505
• Type : Contributed Talk
• Abstract : The closed form expression for the price of the British put and call options have long been established where both interest rate and volatility are assumed to be constant. In reality, these assumptions do not fully reflect the variable nature of the financial markets. In this paper, we derived a closed form expression for the arbitrage-free price of the British call option by assuming stochastic interest rate which follows the Cox-Ingersoll-Ross model and constant volatility.
• Classification : 62P05
• Format : Talk at Waseda University
• Author(s) :
  • Felipe Jr Raypan Sumalpong (Mindanao State University - Iligan Institute of Technology)
  • Kreanne Falcasantos (Mindanao State University - Iligan Institute of Technology)

[02348] Multi-day Value-at-Risk estimation by GARCH and Extreme Value Theory

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E505
• Type : Contributed Talk
• Abstract : The conventional VaR models have been unable to predict huge losses by market prices because these underestimate the probability of extreme price fluctuations. To overcome this problem, McNeil and Frey introduced a two-step approach combining the GARCH model and EVT. In this study, we investigate the estimation of multi-day VaR based on a bootstrapping simulation approach with GARCH-EVT, as well as perform back-testing in order to evaluate its ability to provide appropriate multi-day VaR estimation.
• Classification : 62P05
• Format : Talk at Waseda University
• Author(s) :
  • Ichiro Nishi (Tokio Marine Holdings, Inc.)

[02034] Relation between transaction costs and search frictions in optimal maximization

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E505
• Type : Contributed Talk
• Abstract : We consider an optimal investment problem to maximize expected power-utility of random terminal wealth in a market with two types of illiquidity: transaction costs and search frictions. We suppose an investor trades only at arrival times of Poisson process, and pays proportional transaction costs for purchasing or selling stocks. We characterize a unique optimal trading strategy and provide asymptotic expansions on small transaction costs and small search frictions for boundaries of no-trade region and value function.
• Classification : 62P05, 49N90, Financial mathematics, Stochastic analysis
• Format : Talk at Waseda University
• Author(s) :
  • Tae Ung Gang (KAIST Stochastic Analysis and Application Research Center)
  • Jin Hyuk Choi (UNIST)

[00250] Formation of delta shock waves and vacuum states in the vanishing pressure limit of the Riemann solution to the isentropic Euler system for logarithmic equation of state with the Coulomb-like friction term

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E505
• Type : Contributed Talk
• Abstract : We investigate the limiting behavior of the Riemann solution to the isentropic Euler equations for logarithmic equation of state with the Coulomb-like friction term. The formation of vacuum state and delta shock waves are identified and analyzed when the pressure vanishes. Unlike the homogeneous case, the Riemann solution is no longer self-similar. We prove that the Riemann solution of the isentropic Euler equations for logarithmic equation of state with friction term converges to the Riemann solution of the zero-pressure gas dynamics system with a body force when the pressure vanishes.
• Classification : 35L65, 35L67, 35L45
• Format : Talk at Waseda University
• Author(s) :
  • Anupam Sen (Post Doctoral Fellow at Centre for Applicable Mathematics, Tata Institute of Fundamental Research)

MS [00960] Hierarchical Low Rank Tensors and DNNs for High-dimensional Approximation

room : E506

• [04419] Low-rank tensor approximation of high-dimensional functions
  • Format : Talk at Waseda University
  • Author(s) :
    • Helmut Harbrecht (University of Basel)
    • Michael Griebel (University of Bonn)
    • Reinhold Schneider (Technical University of Berlin)
  • Abstract : In this talk, we analyze tensor approximation schemes for high-dimensional functions in the continuous setting. To this end, we assume that the function to be approximated lies either in an isotropic Sobolev space or an anisotropic Sobolev space. We apply successively the truncated singular value decomposition in order to discuss the cost when approximating the function under consideration in the continuous analogues of tensor formats such as the Tucker tensor format or the tensor train format.
• [03995] Parameter-dependent multigrid method using low-rank tensor formats
  • Format : Talk at Waseda University
  • Author(s) :
    • Tim Andreas Werthmann (RWTH Aachen University)
    • Lars Grasedyck (RWTH Aachen University)
  • Abstract : We consider a parameter-dependent linear system motivated by a diffusion problem. The combination of all finitely many parameters leads to an exponential scaling of the computational effort in the number of parameters, the so-called curse of dimensionality. To break this curse, we use low-rank tensor formats to represent this system. We introduce the parameter-dependent multigrid method to solve such a high-dimensional system within low-rank tensor formats.
• [04205] Alternating nonnegative factorizations for low-rank tensor formats
  • Format : Talk at Waseda University
  • Author(s) :
    • Maren Klever (RWTH Aaachen University)
    • Lars Grasedyck (RWTH Aachen)
    • Sebastian Kraemer (RWTH Aachen University)
  • Abstract : Low-rank tensor formats allow for efficient handling of high-dimensional objects. If the quantity of interest is nonnegative, we want to preserve this property by constraining all cores to be nonnegative. Common alternating strategies reduce the high-dimensional problem to a sequence of low-dimensional subproblems, but often suffer from slow convergence and persistence in local minima. To reduce these inconveniences, we propose a new quasi-orthogonalization strategy as an intermediate step between the alternating minimization steps that preserves nonnegativity.
• [04392] Tensor surrogates for sensitivity analysis in the presence of polymorphic uncertainties
  • Format : Talk at Waseda University
  • Author(s) :
    • Dieter Moser (RWTH Aachen University)
  • Abstract : Sensitivity analysis identifies the input parameters that have the greatest influence on model output. However, when input parameters are polymorphic, meaning that epistemic and aleatory uncertainty is present, traditional sensitivity analysis methods based on probabilistic modelling of the uncertainty have to be adapted. A measurement of distances between polymorphic uncertainties is needed to measure the effect of the input parameters. In this talk, we will discuss how hierarchical tensor surrogates are beneficial for such an adapted sensitivity analysis.

MS [00917] High-dimensional regression and sampling

room : E507

• [05486] Lattice-based algorithms for multivariate function approximation
  • Format : Talk at Waseda University
  • Author(s) :
    • Frances Kuo (UNSW Sydney)
  • Abstract : This will be a talk on using lattices for multivariate function approximation.
• [05565] Efficient recovery of non-periodic multivariate functions via samples
  • Format : Talk at Waseda University
  • Author(s) :
    • Nicolas Nagel (Chemnitz University of Technology)
    • Tino Ullrich (Chemnitz University of Technology)
    • Kai Lüttgen (Chemnitz University of Technology)
    • Felix Bartel (Chemnitz University of Technology)
  • Abstract : Based on previous observations on function recovery from samples via Chebyshev polynomials, we introduce a periodization technique which preserves smoothness and thus, via know results for the periodic case, yields an efficient recovery algorithm for non-periodic functions. Together with deterministic subsampling algorithms we can prove, for the first time, near optimal bounds on the approximation error and support these claims with numerical experiments. This talk is based on work together with Felix Bartel, Kai Lüttgen and Tino Ullrich.
• [04593] Polynomial tractability for integrating functions with slowly decaying Fourier series
  • Format : Talk at Waseda University
  • Author(s) :
    • Takashi Goda (The University of Tokyo)
  • Abstract : This talk is concerned with high-dimensional numerical integration problem. In this context, polynomial tractability refers to the scenario where the minimum number of function evaluations required to make the worst-case error less than or equal to a tolerance $\varepsilon$ grows only polynomially with respect to $\varepsilon^{-1}$ and the dimension $d$. For function spaces that are \emph{unweighted}, meaning that all variables contribute equally to the norm of functions, there are many negative results known in the literature that exhibit the curse of dimensionality. The aim of this paper is to show a contrasting result by introducing a non-trivial unweighted function space with absolutely convergent Fourier series that exhibits polynomial tractability with an explicit quasi-Monte Carlo rule.

MS [02181] Numerical methods and analysis for linear systems and eigenvalue problems

room : E508

• [03254] Interpretation of partial convergence from space partition for linear systems
  • Format : Talk at Waseda University
  • Author(s) :
    • Yanfei Jing (University of Electronic Science and Technology of China)
    • Luc Giraud (Inria Bordeaux -- Sud-Ouest)
    • Yanfei Xiang (Cerfacs, Inria Bordeaux -- Sud-Ouest)
  • Abstract : Efficient solution of large-scale systems of linear equations with multiple right-hand sides is important. Partial convergence and inexact breakdown detection mechanism in the block classical GMRES method characterized by Robbe and Sadkane is a significant progress. We interpret such partial convergence from space partition, providing flexible choices for approximation search subspace at each iteration. Beyond, we report our recent progress in block GMRES-type solvers, and show the efficiency of our solvers by some typical numerical experiments..
• [04340] The FEAST algorithm accelerated by subspace expansion for eigenproblems
  • Format : Talk at Waseda University
  • Author(s) :
    • Guojian Yin (Shenzhen University)
  • Abstract : The FEAST algorithm, a contour-integral based eigensolver, was developed for computing the eigenvalues inside a given region, along with their eigenvectors, of generalized eigenproblems. The FEAST algorithm is always fast, stable and easily parallelizable. It can be understood as an accelerated subspace iteration algorithm in conjunction with the Rayleigh–Ritz procedure. Unlike the classic subspace eigensolvers, the FEAST algorithm does not include a subspace expansion procedure when updating the search subspace but filters the search subspace iteratively using an approximate spectral projector. In this talk, I will introduce a subspace expansion scheme for the FEAST algorithm with the hope of producing a better search subspace and the improving convergence rate, especially when it comes to the ill-conditioned problems.
• [03264] Computing eigenvalues of semi-infinite quasi-Toeplitz matrices
  • Format : Talk at Waseda University
  • Author(s) :
    • Dario Bini (University of Pisa)
    • Bruno Iannazzo (University of Perugia)
    • Beatrice Meini (University of Pisa)
    • Jie Meng (Ocean University of China)
    • Leonardo Robol (University of Pisa)
  • Abstract : A quasi-Toeplitz (QT) matrix is a semi-infinite matrix of the form $A=T(a)+E$ where $T(a)$ is the Toeplitz matrix with entries $(T(a))_{i,j}=a_{j-i}$, for $a_{j-i}\in\mathbb C$, $i,j\ge 1$, while $E$ is a matrix representing a compact operator in $\ell^2$. The matrix $A$ is finitely representable if $a_k=0$ for $k<-m$ and for $k>n$, given $m,n>0$, and if $E$ has a finite number of nonzero entries. The problem of numerically computing eigenpairs of a finitely representable QT matrix is investigated, i.e., pairs $(\lambda, v)$ such that $A v=\lambda v$, with $\lambda\in\mathbb C$, $v=(v_j)_{j\in\mathbb Z^+}$, $ v\ne 0$, and $\sum_{j=1}^\infty |v_j|^2<\infty$. It is shown that the problem is reduced to a finite nonlinear eigenvalue problemof the kind $ WU(\lambda) \beta=0$, where $W$ is a constant matrix and $U$ depends on $\lambda$ and can be given in terms of either a Vandermonde matrix or a companion matrix. Algorithms relying on Newton's method applied to the equation $\det WU(\lambda)=0$ are analyzed. Numerical experiments show the effectiveness of this approach.
• [03454] Preconditioning techniques for nonlinear eigenvalue problem expressed in non-monomial basis
  • Format : Talk at Waseda University
  • Author(s) :
    • Hongjia Chen (Nanchang University)
  • Abstract : One of the most successful methods for solving a polynomial (PEP) or rational eigenvalue problem (REP) is to recast it, by linearization, as an equivalent but larger generalized eigenvalue problem which can be solved by standard eigensolvers. In this work, we investigate the backward errors of the computed eigenpairs incurred by the application of the well-received compact rational Krylov (CORK) linearization. Our treatment is unified for the PEPs or REPs expressed in various commonly used bases, including Taylor, Newton, Lagrange, orthogonal, and rational basis functions. We construct one-sided factorizations that relate the eigenpairs of the CORK linearization and those of the PEPs or REPs. With these factorizations, we establish upper bounds for the backward error of an approximate eigenpair of the PEPs or REPs relative to the backward error of the corresponding eigenpair of the CORK linearization. These bounds suggest scaling techniques to improve the accuracy of the computed eigenpairs. We show, by numerical experiments, that the actual backward errors can be successfully reduced by scaling and the errors, before and after scaling, are both well predicted by the bounds.

MS [00584] Advanced Methods for Structured Eigenvalue Problems and Nonlinear Equations

room : E603

• [01112] Nonlinear Energy Minimization for Simplicial Manifold Parameterizations
  • Format : Talk at Waseda University
  • Author(s) :
    • Mei-Heng Yueh (National Taiwan Normal University)
  • Abstract : The parameterization problem aims to efficiently compute a diffeomorphism between a simplicial manifold and a specified canonical domain. In this talk, I will introduce the theoretical and computational aspects of nonlinear energy minimization for the computation of parameterizations of simplicial manifolds that preserve the specified geometry property. Applications to manifold registration and image processing will be demonstrated to show the effectiveness of parameterizations.
• [01534] Two harmonic Jacobi–Davidson methods for computing a partial GSVD of a large matrix pair
  • Format : Talk at Waseda University
  • Author(s) :
    • Jinzhi Huang (Soochow University)
    • Zhongxiao Jia (Tsinghua University)
  • Abstract : Two harmonic extraction-based Jacobi–Davidson (JD) type algorithms are proposed to compute a partial generalized singular value decomposition (GSVD) of a large regular matrix pair. They are called cross product-free (CPF) and inverse-free (IF) harmonic JDGSVD algorithms, abbreviated as CPF-HJDGSVD and IF-HJDGSVD, respectively. Compared with the standard extraction-based JDGSVD algorithm, the harmonic extraction-based algorithms converge more regularly and suit better for computing GSVD components corresponding to interior generalized singular values. Thick-restart CPF-HJDGSVD and IF-HJDGSVD algorithms with some deflation and purgation techniques are developed to compute more than one GSVD components. Numerical experiments confirm the superiority of CPF-HJDGSVD and IF-HJDGSVD to the standard extraction-based JDGSVD algorithm.
• [01473] Harmonic multi-symplectic Lanczos algorithm for quaternion singular triplets
  • Format : Talk at Waseda University
  • Author(s) :
    • XUAN LIU (University of Macau)
    • Zhigang Jia (Jiangsu Normal University)
    • Jingfei Zhu (Jiangsu Normal University)
    • Meixiang Zhao (Jiangsu Normal University)
  • Abstract : The computation of quaternion singular triplets has become one of the core targets of color image processing. A novel harmonic multi-symplectic Lanczos algorithm is presented for approximating extreme quaternion singular triplets. The underlying theory is to preserve an algebraic structure during the partial bidiagonalization, the argumentation, and the restarted bidiagonalization. The proposed algorithm is successfully applied to color video semantic segmentation.
• [01319] The asymptotic analysis of generalized orthogonal flows
  • Format : Talk at Waseda University
  • Author(s) :
    • Shih-Feng Shieh (National Taiwan Normal University)
  • Abstract : This talk is concerned with the matrix differential equation approximating the k-dimensional dominant eigenspace of a matrix. The solution of the matrix differential equation is orthogonal and is called generalized orthogonal flow. The existence and uniqueness of the generalized orthogonal flow are guaranteed for all time tЄ R. An orthogonal flow, which has the shortest arc-length, has been constructed and is called the best path of generalized orthogonal flows. We show that the best path is Oja's flow. We also analyze the asymptotic behaviors and the convergence rate of the best path.

contributed talk: CT098

room : E605

[00302] Manifold-Free Riemannian Optimization

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E605
• Type : Contributed Talk
• Abstract : Optimization problems constrained to a smooth manifold can be solved via the framework of Riemannian optimization. To that end, a geometrical description of the constraining manifold, e.g., tangent spaces, retractions, and cost function gradients, is required. In this talk, we present a novel approach that allows performing approximate Riemannian optimization based on a manifold learning technique, in cases where only a noiseless sample set of the cost function and the manifold’s intrinsic dimension are available.
• Classification : 65K05, 53Z50, 65D15
• Format : Talk at Waseda University
• Author(s) :
  • Boris Shustin (Tel-Aviv University)
  • Haim Avron (Tel-Aviv University)
  • Barak Sober (The Hebrew University of Jerusalem)

[00527] A fast Multiplicative Update algorithm for non-negative matrix factorization

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E605
• Type : Contributed Talk
• Abstract : This work proposes an efficient algorithm called fastMU (Multiplicative Updates) to deal with a Non-Negative Matrix Factorization problem, based on majorization minimization principle. We derive theoretical convergence results and show the effectiveness of our method through comparison with state-of-the-art methods on both synthetic and realistic data. Practical results show that fastMU is often several orders of magnitude faster than the regular MU proposed by Lee and Sung, and can even be competitive with state-of-the-art methods.
• Classification : 65Kxx, 90Cxx
• Format : Talk at Waseda University
• Author(s) :
  • Mai-Quyen PHAM (IMT Atlantique)
  • Jeremy Cohen (CREATIS, CNRS)
  • Thierry Chonavel (IMT Atlantique)

[00693] Enzyme: Fast and Effective Automatic Differentiation for Academia and Industry

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E605
• Type : Industrial Contributed Talk
• Abstract : Automatic differentiation (AD) is key to training neural networks, Bayesian inference, and scientific computing. Applying these techniques requires rewriting code in a machine learning framework or manually providing derivatives. We present Enzyme, an AD extension for the industry-standard LLVM/MLIR compiler. Enzyme differentiates programs in any LLVM-based language. Unlike traditional tools, Enzyme performs AD on optimized code, resulting in a 4.2x speedup on the CPU and orders of magnitude speedup on the GPU.
• Classification : 65Kxx, 65Yxx, 68Vxx
• Format : Talk at Waseda University
• Author(s) :
  • William Steven Moses (MIT)
  • Valentin Churavy (MIT)
  • Ludger Paehler (TUM)
  • Oleksandr Zinenko (Google)

[00842] Iterative projection methods for solving cone-constrained eigenvalue complementarity problems

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E605
• Type : Contributed Talk
• Abstract : Cone-constrained eigenvalue complementarity problems are associated with unstable modes and vibrations of dynamic systems in engineering. In this talk, iterative projection methods are proposed to quickly search the corresponding K-eigenvalues and K-eigenvectors. Particularly, it is also designed to find specific solutions of the considered problem. Convergence analysis is studied in detail and the sufficient conditions are given. Numerical results are shown to confirm the advantages of our algorithms.
• Classification : 65K15, 15A42
• Format : Talk at Waseda University
• Author(s) :
  • Nan Li (Nagoya University)
  • Tomohiro Sogabe (Nagoya University)
  • Jun-Feng Yin (Tongji University)
  • Tomoya Kemmochi (Nagoya University)
  • Shao-Liang Zhang (Nagoya University)

[01232] A MESH-LESS, RAY-BASED DEEP NEURAL NETWORK METHOD FOR THE HELMHOLTZ EQUATION WITH HIGH FREQUENCY

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E605
• Type : Contributed Talk
• Abstract : We develop a mesh-less, ray-based deep neural network method to solve the Helmholtz equation with high frequency. This method does not use an adaptive mesh refinement method, nor does it design a numerical scheme using some specially designed basis function to calculate the numerical solution, but it has the advantages of easy implementation and no mesh. We have carried out various numerical examples to prove the accuracy and efficiency of the proposed nnumerical method.
• Classification : 65K05
• Format : Online Talk on Zoom
• Author(s) :
  • andy L yang (DutchFork High school)

MS [00517] Numerical Modelling of Highly Flexible Structures for Industrial Applications

room : E606

• [02070] Augmented Lagrangian contact formulation of the 2D Euler elastica
  • Format : Talk at Waseda University
  • Author(s) :
    • Martina Stavole (Friedrich-Alexander-Universität Erlangen-Nürnberg)
    • Rodrigo Takuro Sato Martín de Almagro (Friedrich-Alexander-Universität Erlangen-Nürnberg)
    • Olivier Brüls (Université de Liège )
    • Sigrid Leyendecker (Friedrich-Alexander-Universität Erlangen-Nürnberg)
  • Abstract : In this work we show an application of an augmented Lagrangian formulation to simulate contact between an elastic curve and a narrow environment with rigid walls. Our goal is to provide fast and accurate simulations of endoscopic procedures.
• [02324] The velocity-based formulation for static and dynamic analysis of non-linear three-dimensional frames
  • Format : Talk at Waseda University
  • Author(s) :
    • Dejan Zupan
    • Sudhanva Kusuma Chandrashekhara (Unversity of Ljubljana)
    • Eva Zupan (University of Ljubljana)
  • Abstract : The choice of primary interpolated variables is highly important in numerical formulations of three-dimensional frame-like structures. The crucial idea exploited in our approach is to employ velocities and angular velocities as the primary unknowns, which enables us the use of standard additive interpolation without violating the properties of configuration space. The main advantage of the proposed solution method is in its simplicity, robustness and long-term stability.
• [02419] Half-explicit time integration of constrained mechanical systems on Lie groups
  • Format : Online Talk on Zoom
  • Author(s) :
    • Martin Arnold (Martin Luther University Halle-Wittenberg)
  • Abstract : Recently, there has been new interest in the local coordinates approach to Lie group time integration. The present paper contributes a novel half-explicit Lie group integrator to this field of research. This half-explicit integrator combines an explicit Runge-Kutta Munthe-Kaas method with the index-2 formulation of the equations of motion for constrained mechanical systems. We construct methods of order up to $p=5$ and illustrate their favourable properties by numerical test results.
• [02155] Frequency-dependent damping as forcing on multisymplectic integrators
  • Format : Online Talk on Zoom
  • Author(s) :
    • Rodrigo Takuro Sato Martín de Almagro (FAU - Lehrstuhl für Technische Dynamik)
    • Sigrid Leyendecker (FAU - Lehrstuhl für Technische Dynamik)
  • Abstract : Multisymplectic integrators are geometric integration methods with interesting conservation properties. However, for the temporal integration of flexible structures it may be desirable to dampen high-frequency modes. In this talk we propose a simple frequency-dependent damping model which can be considered as additional forcing. We implement it together with multisymplectic integrators and compare its performance with the generalized alpha method, a popular numerical method for this application due to its frequency-dependent numerical damping.

MS [00340] New trends in phase fields: theory & applications

room : E701

MS [00624] At the interface between neural networks and differential equations

room : E702

• [01481] Operator learning and nonlinear model reduction by deep neural networks
  • Format : Talk at Waseda University
  • Author(s) :
    • Wenjing Liao (Georgia Institute of Technology)
  • Abstract : This talk focuses on the problem of operator learning to learn an operator between function spaces from data. Model reduction plays a significant role, to reduce the data dimension and the problem size. We consider a neural network architecture to utilize low-dimensional nonlinear structures in model reduction, and prove an upper bound of the generalization error. Our theory shows that, the sample complexity depends on the intrinsic dimension of the model.
• [01838] A deep learning framework for geodesics under spherical Wasserstein-Fisher-Rao metric
  • Format : Talk at Waseda University
  • Author(s) :
    • Yang Jing (Shanghai Jiao Tong University)
  • Abstract : Wasserstein-Fisher-Rao (WFR) distance is a family of metrics to gauge the discrepancy of two measures. Compared to the case for Wasserstein distance, the understanding of geodesics under spherical WFR is less clear . We develop a deep learning framework to compute geodesics under spherical WFR metric, and the learned geodesics can be adopted to generate weighted samples. Our framework can be beneficial for applications with given weighted samples, especially in Bayesian inference.
• [01927] Mean-field Analysis of Piecewise Linear Solutions for Wide ReLU Networks
  • Format : Talk at Waseda University
  • Author(s) :
    • Marco Mondelli (Institute of Science and Technology Austria (ISTA))
  • Abstract : We consider a two-layer ReLU network trained via SGD for univariate regression. By connecting the SGD dynamics to the solution of a gradient flow, we show that SGD is biased towards a simple solution: at convergence, the ReLU network implements a piecewise linear map of the inputs, and the number of "knot" points - i.e., points where the tangent of the ReLU network estimator changes - between two consecutive training inputs is at most three.
• [02274] On the Mean-field Theory of Neural Network Training
  • Format : Talk at Waseda University
  • Author(s) :
    • Zhengdao Chen (Google)
  • Abstract : To understand the training of wide neural networks, prior studies have considered the infinite-width mean-field limit of two-layer neural networks, whose training dynamics is characterized as the Wasserstein gradient flow of a probability distribution. In this talk, we will present a mean-field theory for a type of three-layer neural networks whose first-layer weights are random and fixed, through which we prove a linear-rate convergence guarantee and generalization bounds.

MS [00721] Data-driven and Model Reduction methods for Subsurface Applications

room : E703

• [02709] Optimality of statistical criterion in hyper-reduction
  • Format : Talk at Waseda University
  • Author(s) :
    • Siu Wun Cheung (Lawrence Livermore National Laboratory)
  • Abstract : While projection-based reduced order models can reduce the dimension of solutions, there may still be nonlinear terms which scale with the full order dimension. Hyper-reduction techniques are sampling-based methods that further reduce computational complexity of nonlinear terms. In this talk, we will view the state-of-the-art Discrete Empirical Interpolation Method from the perspective of optimal design, and introduce a new hyper-reduction method based on optimality of another statistical criterion.
• [04174] Least-squares Method for Recovering Multiple Medium Parameters
  • Format : Talk at Waseda University
  • Author(s) :
    • Ying Liang (Purdue University)
  • Abstract : We present a two-stage least-squares method for inverse medium problems of reconstructing multiple unknown coefficients simultaneously from noisy data. A direct sampling method is applied to detect the location of the inhomogeneity in the first stage, while a total least-squares method with a mixed regularization is used to recover the medium profile in the second stage. The total least-squares method is designed to minimize the residual of the model equation and the data fitting, along with an appropriate regularization, in an attempt to significantly improve the accuracy of the approximation obtained from the first stage. We shall also present an analysis on the well-posedness and convergence of this algorithm. Numerical experiments are carried out to verify the accuracies and robustness of this novel two-stage least-squares algorithm, with high tolerance of noise in the data.
• [03801] Adaptive partially explicit splitting scheme for multiscale flow problems
  • Format : Online Talk on Zoom
  • Author(s) :
    • Yating Wang (Xi'an Jiaotong University)
    • Wing Tat Leung (City University of Hong Kong)
  • Abstract : In this talk, we will introduce an adaptive framework for a partially explicit splitting scheme of flow problems in high-contrast multiscale media. Due to the heavy computational burden is for the multiscale coefficient with high-contrast, in this work, we utilize a stable multirate temporal splitting scheme, and construct multiscale subspaces to handle the fast flow and slow flow parts separately. The construction of multiscale spaces ensures that the time-step size is independent of the contrast. We then derive both temporal and spatial error estimators to identify local regions where enrichments are needed for two components of the solutions. An adaptive algorithm is then proposed to achieve higher computational efficiency with the desired accuracy.

MS [01672] High accuracy compact methods for partial differential equations

room : E704

• [05366] Spectral Element Method for Parabolic Problems with Corner Singularities
  • Format : Talk at Waseda University
  • Author(s) :
    • Sanuwar Ahmed Choudhury (National Institute of Technology Silchar Assam India)
    • Pankaj Biswas (National Institute of Technology Silchar Assam India)
  • Abstract : In many engineering applications, reconstruction of temperature generated from incomplete data causes corner singularities. In such cases, a solution of parabolic initial-boundary-value-problems(IBVP) on nonsmooth-domains is required. Spectral-element methods give exponential accuracy for smooth solutions. Generating geometric meshes at the neighborhood of the corners on the space-domain a parallel least-squares-spectral-element-method using MPI is presented here to resolve the singularities. Numerical scheme has been developed in the frame-work of Sobolev spaces and examples are presented to validate the estimates.

MS [00262] numerical analysis, modeling and applications in phase-field its relevant methods

room : E705

• [05280] Approximating Structurally Unstable Over-determined Systems of PDEs
  • Author(s) :
    • Qi Wang (University of South Carolina)
  • Abstract : Models for nonequilibrium phenomena are normally consisted of differential equations, from which some physically important relations can be deduced. Together, they form an extended, over-determined system of equations which is normally structurally unstable. Structure-preserving approximation thus ensues, which are known numerically as structure-preserving algorithms/schemes. In this presentation, I will discuss some structure-preserving numerical strategies for developing numerical algorithms for thermodynamically consistent multiphase materials models, which are derived from thermodynamical principles.
• [04941] Phase-field modelling of three-phase solidification with density variation
  • Author(s) :
    • Pengtao Yue (Virginia Tech)
    • Jiaqi Zhang (Beijing Normal University-Hong Kong Baptist University United International College)
    • Yichen Li (Virginia Tech)
  • Abstract : We present a non-isothermal quasi-incompressible phase-field model for three-phase solidification that involves water, ice, and air. Water-ice phase transition and water-air interface are handled by the Allen-Cahn and Cahn-Hilliard equations, respectively. Constitutive relations are derived based on non-negative entropy production. Our model automatically captures curvature and pressure effects as dictated by the Gibbs-Thomson and Clausius-Clapeyron equations, as well as volume expansion during solidification. Numerical results on tip formation of a freezing droplet will be presented.
• [03012] Energy stability analysis and error estimate of a maximum bound principle preserving scheme for the dynamic Ginzburg--Landau equations under the temporal gauge
  • Author(s) :
    • Zhonghua Qiao (The Hong Kong Polytechnic University)
  • Abstract : This paper proposes a decoupled numerical scheme of the time-dependent Ginzburg--Landau equations under the temporal gauge. For the magnetic potential and the order parameter, the discrete scheme adopts the second type Ned${\rm \acute{e}}$lec element and the linear element for spatial discretization, respectively; and a linearized backward Euler method and the first order exponential time differencing method for time discretization, respectively. The maximum bound principle (MBP) of the order parameter and the energy dissipation law in the discrete sense are proved. The discrete energy stability and MBP-preservation can guarantee the stability and validity of the numerical simulations, and further facilitate the adoption of adaptive time-stepping strategy, which often plays an important role in long-time simulations of vortex dynamics, especially when the applied magnetic field is strong. An optimal error estimate of the proposed scheme is also given. Numerical examples verify the theoretical results of the proposed scheme and demonstrate the vortex motions of superconductors in an external magnetic field.
• [04302] Multi-phase-field modeling of grain growth and multiphase flow in additive manufacturing
  • Format : Online Talk on Zoom
  • Author(s) :
    • Tomohiro Takaki (Kyoto Institute of Technology)
  • Abstract : A multi-phase-field model for predicting material microstructures formed during the powder bed fusion additive manufacturing of a metallic alloy is developed. Here, multi-phase-field models for solidification and multiphase flow problems are coupled to express polycrystalline solidification with melt flow in the melt pool.

MS [01028] High-order numerical methods for nonlinear PDEs

room : E708

• [05392] Pointwise-in-time a posteriori error control for higher-order discretizations of time-fractional parabolic equations
  • Author(s) :
    • Natalia Kopteva
    • Sebastian Franz (Technical University Dresden)
  • Abstract : Time-fractional parabolic equations with a Caputo time derivative are considered. For such equations, we explore and further develop the new methodology of the a-posteriori error estimation and adaptive time stepping proposed in [N. Kopteva, Pointwise-in-time a posteriori error control for time-fractional parabolic equations, Appl. Math. Lett., 123 (2022)]. We improve the earlier time stepping algorithm based on this theory, and specifically address its stable and efficient implementation in the context of high-order methods. The considered methods include an L1-2 method and continuous collocation methods of arbitrary order, for which adaptive temporal meshes are shown to yield optimal convergence rates in the presence of solution singularities.
• [05204] An $L^1$ mixed DG method for second-order Elliptic Equations in the Non-divergence Form
  • Author(s) :
    • Weifeng Qiu (City University of Hong Kong)
    • Jin Ren (Old Dominion University)
    • Ke Shi (Old Dominion University)
    • Yuesheng Xu (Old Dominion University)
  • Abstract : In this talk we present an $L^1$ mixed DG method for second-order elliptic equations in the non-divergence form. The elliptic PDE in nondivergence form arises in the linearization of fully nonlinear PDEs. Due to the nature of the equations, classical finite element methods based on variational forms can not be employed directly. In this work, we propose a new optimization based finite element method which combines the classical DG framework with recently developed $L^1$ optimization technique. Convergence analysis in both energy norm and $L^{\infty}$ norm are obtained under weak regularity assumption of the PDE ($H^1$). Such $L^1$ optimization problems are nondifferentiable and invalidate traditional graidnet methods. To overcome this difficulty, we characterize solutions of $L^1$ optimization as fixed-points of proximity equations and utilize matrix splitting technique to obtain a class of fixed-point proximity algorithms with convergence analysis. In addition, various numerical examples will be displayed to validate the analysis in the end.
• [02310] New analysis of a mixed FEM for Ginzburg-Landau Equations
  • Author(s) :
    • Huadong Gao (Huazhong University of Science and Technology)
  • Abstract : This talk is concerned with new error analysis of a lowest-order backward Euler Galerkin-mixed finite element method for the time-dependent Ginzburg-Landau equations. The method is based on a commonly-used non-uniform approximations $(P_1, ND_1 \times RT_0)$, which has been widely used. We establish the second-order accuracy for the order parameter in spatial direction, although the accuracy for $(\mathbf{curl} \mathbf{A}, \mathbf{A})$ is in the first order only. Our numerical experiments confirm the optimal convergence of $\psi_h$.
• [01989] Spectral analysis of a mixed method for linear elasticity
  • Author(s) :
    • Xiang Zhong (City University of Hong Kong)
    • Weifeng Qiu (City University of Hong Kong)
  • Abstract : We consider a mixed method for linear elasticity eigenvalue problem, which approximates numerically the stress, displacement, and rotation, by piecewise (k+1), k and (k+1)-th degree polynomials (k>=1) on Hseih-Clough-Toucher grids. The numerical eigenfunction of stress is symmetric. By the discrete H^1-stability of numerical displacement, we prove an O(h^(k+2)) approximation to the L^2-orthogonal projection of the eigenspace of exact displacement for the eigenvalue problem, with proper regularity assumption. We also prove that numerical approximation to the eigenfunction of stress is locking free with respect to Poisson ratio. We introduce a hybridization to reduce the mixed method to a condensed eigenproblem and prove an O(h^2) initial approximation of the eigenvalue by using the discrete H^1-stability of numerical displacement.

MS [00179] Advances in forward and inverse problems of wave equations

room : E709

• [00347] Accurate evaluation of Helmholtz layer potentials using Quadrature by two expansions
  • Format : Talk at Waseda University
  • Author(s) :
    • Min Hyung Cho (University of Massachusetts Lowell)
    • Jared Weed (University of Massachusetts Lowell)
    • Lingyun Ding (University of California Los Angeles)
    • Jingfang Huang (University of North Carolina at Chapel Hill)
  • Abstract : The Helmholtz layer potentials are evaluated using the Quadrature by two expansions (QB2X). The QB2X method uses local complex Taylor expansion and planewave-type expansions to achieve a representation that is numerically accurate at all target points inside the leaf box in the hierarchical tree structure. Compared with the original quadrature by the expansion that uses only the local expansion, the QB2X includes explicit nonlinearity from the boundary geometry in the planewave type expansions and it follows standard fast multipole method error analysis. Therefore, QB2X overcomes many challenges quadrature by expansion has and is suitable for complex geometry. The main ideas of the derivation of QB2X using Fourier extension and contour integrals, and numerical results showing the efficiency of QB2X compared with the quadrature by expansion will be presented for both flat and curved boundaries.
• [00411] On the Robustness of Inverse Scattering for Penetrable, Homogeneous Objects
  • Format : Talk at Waseda University
  • Author(s) :
    • Borges Carlos (University of Central Florida)
    • Manas Rachh (Flatiron Institute)
    • Leslie Greengard (New York University and Flatiron Institute)
  • Abstract : In the inverse obstacle scattering problem, one determines the shape of a domain from measurements of the scattered field due to a set of incident fields. For a penetrable obstacle with known sound speed, this can be accomplished by treating the boundary alone as an unknown curve. Alternatively, one can treat the entire object as an unknown and use a volumetric representation, without making use of the known sound speed. Both lead to strongly nonlinear and nonconvex optimization problems for which recursive linearization provides a useful framework. After extending our shape optimization approach developed earlier for impenetrable bodies to penetrable obstacles, we carry out a systematic study of both methods and compare their performance on a variety of examples. Our findings indicate that the volumetric approach is more robust, even though the number of degrees of freedom is significantly larger.
• [00490] A Neural Network Warm-Start Approach for the Inverse Acoustic Obstacle Scattering Problem
  • Format : Talk at Waseda University
  • Author(s) :
    • Manas Rachh (Flatiron Institute)
    • Mo Zhou (Duke University)
    • Jiequn Han (Flatiron Institute)
    • Borges Carlos (University of Central Florida)
  • Abstract : We consider the inverse acoustic obstacle problem for sound-soft star-shaped obstacles in two dimensions. The inverse problem is computationally challenging since the local set of convexity shrinks with increasing frequency and results in an increasing number of local minima in the vicinity of the true solution. In this talk, we present a neural network warm-start approach for solving the inverse scattering problem, where an initial guess is obtained using a trained neural network.
• [04073] Optimal Transportation for Electrical Impedance Tomography
  • Format : Talk at Waseda University
  • Author(s) :
    • Gang BAO (Zhejiang University)
    • Yixuan Zhang (Zhejiang University)
  • Abstract : A new framework is introduced for solving inverse boundary problems with the geodesic based quadratic Wasserstein distance. A general form of the Fréchet gradient is systematically derived by optimal transportation (OT) theory. A fast algorithm based on the new formulation of OT is developed to solve the corresponding optimal transport problem with much improved computational complexity. This framework provides a new computational approach for solving the challenging electrical impedance tomography problem.

MS [00626] Finite element complexes for structure-preservation in continuum mechanics

room : E710

• [02047] Local Exactness of de Rham Conforming Hierarchical B-spline Differential Forms
  • Format : Talk at Waseda University
  • Author(s) :
    • Kendrick M Shepherd (Brigham Young University)
    • Deepesh Toshniwal (TU Delft)
  • Abstract : Conservation laws present in partial differential equations arising in fluid mechanics and electromagnetics are frequently described using the de Rham sequence of differential forms. Stability of numerical methods solving these equations requires discrete preservation of these conservation laws. This talk will present sufficient local exactness criteria for a set of smooth, high-order, isogeometric, locally-refinable spline spaces in Euclidean space of arbitrary dimension in order to enable stable high-order, geometrically-precise finite element analyses.
• [02065] Multigrid solvers for the de Rham complex with optimal complexity in polynomial degree
  • Format : Talk at Waseda University
  • Author(s) :
    • Pablo D. Brubeck (University of Oxford)
    • Patrick Emmet Farrell (University of Oxford)
  • Abstract : We present multigrid solvers for the high-order FEM de Rham complex with the same time and space complexity as sum-factorized operator application. Our approach relies on new finite elements with orthogonality properties on the reference hexahedron. The resulting sparsity enables the fast solution of the patch problems arising in the Pavarino, Arnold–Falk–Winther, and Hiptmair space decompositions, in the separable case. In the non-separable case, the method can be applied to a sparse auxiliary operator.
• [04622] On partially continuous finite element spaces in variational problems of continuum mechanics
  • Format : Talk at Waseda University
  • Author(s) :
    • Adam Sky (University of Luxembourg)
  • Abstract : The use of partially continuous finite element spaces in continuum mechanics is well-established. Common applications are mixed formulations, for example in linear elasticity. While strongly symmetric finite elements for the discretisation of the stresses have been introduced, their mapping from a reference element is non-trivial. As such, in the first part of this talk we will introduce simple mappings for base functions of the Hu-Zhang element, which are applicable to hp-FEM, and discuss related problems in linear elasticity. Linear elasticity represents one limited model of continuum mechanics. With the goal of describing more complex phenomena, generalised continua have been introduced. In the context of the linear relaxed micromorphic model, the strain field is augmented via a microdistortion field. In recent works, it was proven that the field can be defined in H(symCurl), such that well-posedness is maintained. With that in mind, the second part of this talk will discuss novel finite elements for the discretisation of the H(symCurl)-space and their application to the relaxed micromorphic sequence.
• [05396] New Class of Stabilized Mixed FEM for Compressible and Incompressible Nonlinear Elasticity
  • Format : Talk at Waseda University
  • Author(s) :
    • Ali Gerami Matin (The George Washington University)
  • Abstract : In this paper, we introduce two stabilized class of mixed finite element methods with bubble functions and a perturbation method for $2$D and $3$D compressible and incompressible nonlinear elasticity. Two approaches, namely, the $L^{2}$-projection and projections of partly sobolev classes, have been employed to obtain weak formulations. Both structured and unstructured simplicial meshes have been considered to investigate effects of different meshes on our formulation. Finally, by solving some benchmark problems, we investigate performance of the stabilized elements in different circumstances. Benchmark results demonstrate that our stabilized formulation provide a robust and computationally efficient way of simulating compressible, near-incompressible, and incompressible materials. These formulations also show good performance in approximating stress and pressure in bending problems, $2$D and $3$D solids with complex geometries, and heterogeneous bodies.

MS [02479] Recent advances for modeling, numerical algorithm, and applications in electronic structure calculation

room : E711

• [04589] Computations of the ground states and collective excitations of Bose-Einstein condensates
  • Author(s) :
    • Manting Xie (Tianjin University)
    • Hehu Xie (Academy of Mathematics and Systems Science, Chinese Academy of Sciences)
    • Yong Zhang (Tianjin University)
  • Abstract : In this talk, we'll show some efficient and robust numerical methods to study the ground states and collective excitations of Bose-Einstein condensates.
• [03384] Multilevel correction adaptive finite element method for Kohn-Sham equation
  • Format : Talk at Waseda University
  • Author(s) :
    • Fei Xu (Beijing University of Technology)
  • Abstract : An efficient adaptive finite element method is proposed for solving the ground state solution of the Kohn-Sham equation which is based on the combination of the multilevel correction scheme and the adaptive refinement technique. The multilevel correction adaptive finite element method can transform the Kohn-Sham equation into a series of linear boundary value problems on the adaptive partitions and a series of Kohn-Sham equations on very low dimensional spaces. Further, the Hartree potential and the exchange-correlation potential are treated individually, and the algorithm can be performed in an eigenpairwise approach. Therefore, the presented adaptive method for Kohn-Sham equation can arrive at the similar efficiency as that of the adaptive finite element method for the associated linear boundary value problems. 
• [03227] The Wigner function of ground state and one-dimensional numerics
  • Format : Talk at Waseda University
  • Author(s) :
    • Hongfei Zhan (Peking University)
  • Abstract : In this talk, the ground state Wigner function of a many-body system is explored theoretically and numerically. An eigenvalue problem for Wigner function is derived based on the energy operator of the system. On the other hand, a numerical method is designed for solving proposed eigenvalue problem in one dimensional case. Results of several numerical experiments verify our method, where the potential application for large scale system is demonstrated by examples with density functional theory.

MS [00137] Mathematical Aspects of Multiscale Phenomena in Materials and Complex Fluids

room : E802

• [00142] New perspectives on modeling and analysis of grain growth in polycrystals
  • Format : Talk at Waseda University
  • Author(s) :
    • Yekaterina Epshteyn (University of Utah)
    • Katayun Barmak (Columbia University)
    • Chun Liu (IIT)
    • Masashi Mizuno (Nihon University)
  • Abstract : Grain growth in polycrystals is a very complex multiscale process. It can be regarded as the anisotropic evolution of a large cellular network, and can be described by a set of deterministic local evolution laws for the growth of an individual grain combined with stochastic models for the interaction between them. In this talk, we will present new perspectives on modeling, simulation and analysis of the evolution of the grain boundary network in polycrystalline materials.
• [00183] Entropy dissipation methods for Nonlinear inhomogeneous Fokker-Planck models
  • Format : Talk at Waseda University
  • Author(s) :
    • Masashi Mizuno (Nihon University)
    • Yekaterina Epshteyn (University of Utah)
    • Chun Liu (Illinois Institute of Technology)
    • Chang Liu (University of Utah)
  • Abstract : This talk presents long-time asymptotic behavior for the nonlinear Fokker-Planck model: First, for the linear Fokker-Planck equation, we reformulate the entropy dissipation methods with the help of the velocity vector in the continuity equation. Next, we derive the evolution equation for the velocity vector for the nonlinear Fokker-Planck model. Finally, we give a sufficient condition to extend the entropy dissipation method to the nonlinear Fokker-Planck model.
• [00198] Structure-preserving variational discretizations to generalized gradient flows
  • Format : Online Talk on Zoom
  • Author(s) :
    • Chun Liu (Illinois Institute of Technology)
    • Yiwei Wang (University of California, Riverside)
  • Abstract : We'll present a numerical framework for developing structure-preserving variational schemes for various complex fluids models built by the energetic variational approach. The numerical approach starts with the energy-dissipation law of the underlying system and can combine different spatial discretizations, including Eulerian, Lagrangian, particle, and neural-network-based methods. The numerical procedure guarantees the developed schemes are energy stable and can preserve the intrinsic physical constraints. Several applications of this numerical approach will be discussed.
• [00248] Towards upscaling and simulation of coupled [THM] systems with applications to permafrost modeling
  • Format : Online Talk on Zoom
  • Author(s) :
    • Malgorzata Peszynska (Oregon State UniversityOregon State University)
    • Naren Vohra (Oregon State University)
  • Abstract : In the talk we discuss our progress towards multiscale computational modeling of coupled processes in permafrost, frozen ground which is ubiquitous in the Arctic. We focus on its active layer close to the surface whose depth is changing due to changing climate conditions, and we model its thermal state (temperature, and phase status: frozen or thawed), hydrological conditions, and mechanical response to hydrological and thermal controls. We present convergence studies and upscaling from porescale.

MS [00060] Mathematical approaches to collective phenomena

room : E803

• [04763] Multi-fidelity method for a class of kinetic equations with uncertainties
  • Format : Talk at Waseda University
  • Author(s) :
    • Liu Liu (The Chinese University of Hong Kong )
    • Lorenzo Pareschi (University of Ferrara)
    • xueyu zhu (University of Iowa)
  • Abstract : In this talk, we will discuss some recent development on the topic of multi-fidelity methods for solving a class of kinetic equations with uncertainties and multiple scales. The Boltzmann equation, linear transport equation and epidemic transport system will be particularly studied, together with formal error estimates. We will also briefly discuss application of deep learning approaches to study kinetic problems.
• [04788] Brownian HydroDynamics for Confined Electrolyte Solutions
  • Format : Talk at Waseda University
  • Author(s) :
    • Aleksandar Donev (Courant Institute, New York University)
  • Abstract : Electrolyte solutions appear in many engineering systems and processes, such as desalination, microfluidic pumps, and batteries. For confined electrolytes, (quasistatic) long-ranged electrostatic interactions among the particles play a crucial role in the static structure. Similarly, hydrodynamic interactions (HIs) mediated by the solvent are also long-ranged and affect the dynamics in crucial ways. Confinement in slit channel geometries is of particular importance, especially for electrohydrodynamics and electrochemistry near electrodes in devices and batteries. In particular, very thin electric (Debye) double layers with complex structure form near dielectric or metallic boundaries and many important electro-hydrodynamic phenomena occur in this layer. I will discuss the limitations of the classical Poisson-Nernst-Planck-Stokes equations for non-dilute electrolytes, in which the Debye scale is molecular, and present an alternative Brownian HydroDynamics (BD-HI) approach that uses fluctuating hydrodynamics for the solvent but represents the ions as explicit Brownian particles. By using BD-HI we are able to reach much longer (diffusive) time scales than molecular dynamics because of the implicit overdamped solvent, at the expense of loosing some microscopic details.
• [04809] Delay Models of Collective Behavior with Biological and Industrial Applications
  • Format : Talk at Waseda University
  • Author(s) :
    • Jan Haskovec (King Abdullah University of Science and Technology)
  • Abstract : The talk will give an overview of recent results for models of collective behavior governed by delay differential equations. It will focus on models of interacting agents with applications in biology (flocking, swarming), social sciences (opinion formation) and engineering (swarm robotics), where latency (delay) plays a significant role. We will explain that there are two main sources of delay - inter-agent communications and information processing - and show that they have qualitatively different impacts on the group dynamics. We will give an ovierview of analytical methods for studying the asymptotic behavior of the models and their mean-field limits. Finally, motivated by situations where finite speed of information propagation is significant, we will introduce an interesting class of problems where the delay depens nontrivially and nonlinearly on the state of the system, and discuss the available analytical results and open problems here.
• [04973] Model Cascades for Dilute Gases Based on Moment Equations
  • Format : Talk at Waseda University
  • Author(s) :
    • Manuel Torrilhon (RWTH Aachen)
  • Abstract : Dilute gas flows show thermal non-equilibrium due to lack of particle collisions. This requires modeling using the statistical description of kinetic gas theory. Moment equations extend the classical fluid dynamic equations for processes with moderate Knudsen numbers. We will present non-equilibrium models based on moment approximations, which provide a hierarchy of models in a cascading nature. This can be used to estimate model errors and perform model-adaptive simulations.

contributed talk: CT119

room : E804

[01240] Machine Learning based Optimization Algorithm for Stress Prediction

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E804
• Type : Contributed Talk
• Abstract : In this work, an efficient optimization algorithm is developed to predict the stress of a person. The algorithm uses sensor data which are extracted from person’s physiological parameters. The proposed work uses various techniques for smoothing the data and to identify the features from the extracted data. Different experiments are done by considering various output metrics. Based on the comparison with the existing classification algorithms, the proposed algorithm identifies the stress prediction with high accuracy.
• Classification : 68M18, 68M20, 65-04
• Format : Talk at Waseda University
• Author(s) :
  • Pankajavalli Palanisamy Balamani (Bharathiar University)

[00744] On the Burgers-type equations used in soft solid acoustics

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E804
• Type : Contributed Talk
• Abstract : A strain-rate model of soft viscoelastic solid is presented. The constitutive law accounts for finite strain, incompressibility, material frame-indifference, nonlinear elasticity, and viscous dissipation. Shear waves are governed by a nonlinear viscous wave equation, of which a one-way Burgers-type approximate equation is derived. Analysis of the travelling wave solutions shows that the two equations produce distinct solutions, unless amplitudes are infinitesimal. In the inviscid case, links with simple wave theory are established.
• Classification : 74D10, 74J30, 74H10
• Format : Talk at Waseda University
• Author(s) :
  • Harold Berjamin (School of Mathematical and Statistical Sciences, University of Galway, University Road, Galway, Republic of Ireland)

[01019] Particle Swarm Optimization Based Reliable Control Algorithm for Wireless Networks

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E804
• Type : Contributed Talk
• Abstract : This paper deals with the fault-tolerant control problem for Wireless networks based on the particle swarm optimization method. To cope the stability and fault-tolerants simultaneously, a novel fault-tolerant control algorithm is developed. The required conditions of the addressed system are developed with the aid of Lyapunov stability theory. Precisely, the particle swarm optimization algorithm is implemented to optimize the fuzzy controller. Finally, simulation results are provided to demonstrate the effectiveness of the obtained results.
• Classification : 68M07, 68M12, 68M15
• Format : Online Talk on Zoom
• Author(s) :
  • Ponnarasi Loganathan (Bharathiar University)
  • Pankajavalli PB (Bharathiar University)

[00985] A Routing Protocol for Enhancing the QoS in Vehicular Ad hoc Networks

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E804
• Type : Industrial Contributed Talk
• Abstract : The vehicle ad hoc network (VANET) provides various services for safe driving to the driver. The main problem with VANET is routing, since it has much more variation in network topology and node density than conventional mobile ad hoc networks (MANET). In this paper, we propose a QoS routing protocol based on link state information for VANET. The proposed protocol provides an optimal path using link quality and link stability.
• Classification : 68M10, 68M18, 68M15
• Format : Talk at Waseda University
• Author(s) :
  • Jin-Woo Kim (Duksung Women’s University)
  • Jaehee Kim (Duksung Women’s University)

contributed talk: CT123

room : E811

[00773] Machine Learning Model for Thin Metal Sheet Counting and Thickness Measurement

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E811
• Type : Contributed Talk
• Abstract : In this talk we are to discuss about counting stacked metal foils in real time. For the purpose a non-contact method based on broadband X-ray absorption spectra was employed to scan the experimental samples and artificial neural network was built to count and measure thickness of the stacked foil. Further, the attained results are compared with polynomial fitting model and linear regression in order to verify the difference in prediction accuracy of the three models.
• Classification : 68T07, 78M32, 82C32, 62J05, 65D10
• Format : Talk at Waseda University
• Author(s) :
  • Elayaperumal Ayyasamy (Anna University, Chennai)

[00856] Successive image generation though cyclic transformations using CycleGAN

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E811
• Type : Contributed Talk
• Abstract : CycleGAN is a deep generative adversarial networks that performs image to image style translation by learning relationship between two image domains. By using CycleGAN, here we developed a model performing cyclical transformation that generates a series of similar images. This system can be regarded as a dynamical system; it can continuously sample various images along the trajectory of the dynamical system. The chaotic behavior of this deep model was studied.
• Classification : 68T07, 37N99
• Format : Talk at Waseda University
• Author(s) :
  • Takaya Tanaka (Graduate School of Engineering, Fukuoka Institute of Technology)
  • Takaya Tanaka (Graduate School of Engineering, Fukuoka Institute of Technology)
  • Yutaka Yamaguti (Faculty of Information Engineering, Fukuoka Institute of Technology)

[00664] A New Sampling Technique for Learning with Hypergraph Neural Networks

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E811
• Type : Contributed Talk
• Abstract : Hypergraphs can represent higher-order relations among objects. Traditional hypergraph neural networks produce high computational cost and timing. We propose a new sampling technique for learning with hypergraph neural networks. The core idea is to design a layer-wise sampling scheme for nodes and hyperedges to approximate original hypergraph convolution. Notably, the proposed sampling technique allows us to handle large-scale hypergraph learning. Experiment results demonstrate that our proposed model keeps a good balance between time and accuracy.
• Classification : 68T07, 05C65, 62D05, 68T09, large-scale hypergraph learning, hypergraph neural networks, hypergraph sampling, variance reduction, importance sampling
• Format : Talk at Waseda University
• Author(s) :
  • Fengcheng Lu (The University of Hong Kong)
  • Michael Kwok-Po Ng (The University of Hong Kong)

[00817] Understanding Flood Flow Physics via Data-Informed Learning

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E811
• Type : Contributed Talk
• Abstract : Modeling the dynamics of fast-moving floods has historically been an intractable problem due to the inherent complexity and multi-scale physics of the underlying processes involved. Recent advancements in physics-constrained machine learning indicate that neural networks can be used to effectively model phenomena for which physical laws are poorly understood. By combining real data and first principles, we show that we can enhance knowledge about the underlying physics of flood phenomena via the learned constitutive laws.
• Classification : 68T07, 76T99, 86-10
• Format : Talk at Waseda University
• Author(s) :
  • Jonathan Thompson (University of Colorado Colorado Springs)
  • Radu Cascaval (University of Colorado Colorado Springs)

MS [00632] From model-blind to model-aware learning of inverse problems in imaging

room : E812

• [03849] Untrained networks with latent-space disentanglement for motion separation in videos
  • Format : Talk at Waseda University
  • Author(s) :
    • Malena Sabaté Landman (Department of Applied Mathematics and Theoretical Physics, University of Cambridge)
    • Abudllah Abudllah (Department of Mathematics, The Chinese University of Hong Kong)
    • Martin Holler (Institute of Mathematics and Scientific Computing, University of Graz)
    • Karl Kunisch (Institute of Mathematics and Scientific Computing, University of Graz)
  • Abstract : In this talk I will present an algorithm that allows to efficiently isolate different, highly non-linear motion types in video data, using untrained generator networks together with a specific technique for latent space disentanglement that uses minimal, one-dimensional information on some of the underlying dynamics.
• [01569] Continuous Generative Neural Networks for Inverse Problems
  • Format : Talk at Waseda University
  • Author(s) :
    • Giovanni Alberti (University of Genoa)
    • Matteo Santacesaria (University of Genoa)
    • Silvia Sciutto (University of Genoa)
  • Abstract : We study Continuous Generative Neural Networks CGNNs, namely, generative models in the continuous setting. The architecture is inspired by DCGAN, with one fully connected layer, several convolutional layers and nonlinear activation functions. In the continuous L^2 setting, the dimensions of the spaces of each layer are replaced by the scales of a multiresolution analysis of a compactly supported wavelet. We present conditions on the convolutional filters and on the nonlinearity that guarantee that a CGNN is injective. This theory finds applications to inverse problems, and allows for deriving Lipschitz stability estimates for possibly nonlinear infinite-dimensional inverse problems with unknowns belonging to the manifold generated by a CGNN.
• [02780] Learned proximal operators in accelerated unfolded methods with pseudodifferential operators
  • Format : Online Talk on Zoom
  • Author(s) :
    • Andrea Sebastiani (University of Bologna)
    • Tatiana Alessandra Bubba (University of Bath)
    • Luca Ratti (University of Genoa)
    • Subhadip Mukherjee (University of Bath)
  • Abstract : In recent years, hybrid reconstruction frameworks has been proposed by unfolding iterative methods and learning a suitable pseudodifferential correction on the part that can provably not be handled by model-based methods. In this talk, I will present a variant of this approach, where an accelerated iterative algorithm is unfolded and the proximal operator is replaced by a learned operators, as in the PnP framework. The numerical experiments on limited-angle CT achieve promising results.
• [02946] Electrical impedance tomography, virtual X-rays, and stroke
  • Format : Talk at Waseda University
  • Author(s) :
    • Samuli Siltanen (University of Helsinki)
  • Abstract : A connection between Electrical Impedance Tomography (EIT) and X-ray tomography was found in (Greenleaf et al. 2018) using microlocal analysis. Fourier transform applied to the spectral parameter of Complex Geometric Optics solutions produces virtual X-ray projections, enabling a novel filtered back-projection type nonlinear reconstruction algorithm for EIT. This approach is called Virtual Hybrid Edge Detection. Machine learning can be used for classifying stroke (into ischemic and hemorrhagic) based on virtual X-ray profiles of the conductivity.

MS [00908] Machine Learning and Data-Driven Applications using Geometric Integration

room : E817

• [02911] Auxiliary Functions as Koopman Observables
  • Format : Online Talk on Zoom
  • Author(s) :
    • Jason John Bramburger (Concordia University)
  • Abstract : Many important statements about dynamical systems can be proved by finding scalar-valued auxiliary functions whose time evolution along trajectories obeys certain pointwise inequalities that imply the desired result. The most familiar of these auxiliary functions is a Lyapunov function to prove steady-state stability, but such functions can also be used to bound averages of ergodic systems, define trapping boundaries, and so much more. In this talk I will highlight a method of identifying auxiliary functions from data using polynomial optimization. The method leverages recent advances in approximating the Koopman operator from data, so-called extended dynamic mode decomposition, to provide system-level information without system identification. The result is a model-agnostic computational method that can be used to bound quantities of interest and develop optimal state-dependent feedback controllers, while also functioning as a pre-conditioner to discovering accurate and parsimonious dynamical models from the data.
• [03401] Conservative Hamiltonian Monte Carlo
  • Format : Online Talk on Zoom
  • Author(s) :
    • Geoffrey McGregor (University of Toronto)
    • Andy Wan (University of Northern British Columbia)
  • Abstract : Markov Chain Monte Carlo (MCMC) methods enable us to extract meaningful statistics from complex distributions which frequently appear in parameter estimation, Bayesian statistics, statistical mechanics and machine learning. However, as the dimensionality of the problem increases, the convergence rate of MCMC sequences toward the stationary distribution slows down dramatically. This has led to the development of Hamiltonian Monte Carlo (HMC) [Duane et al. ‘87, Neal ‘93], to improve performance by solving a Hamiltonian system using symplectic numerical methods. However, modern high-dimensional applications still pose a significant challenge for HMC. In this talk, we introduce Conservative Hamiltonian Monte Carlo (CHMC), which alternatively utilizes an energy-preserving numerical method, known as the Discrete Multiplier Method. We show that CHMC converges to the correct stationary distribution under appropriate conditions, and provide numerical examples showcasing improvements in convergence rates over HMC in high-dimensional problems. Furthermore, we also will present numerical results on Bayesian parameter estimation using CHMC.
• [03462] Model Reduction of Hamiltonian Systems based on Nonlinear Approximation Methods
  • Format : Talk at Waseda University
  • Author(s) :
    • Silke Glas (University of Twente)
  • Abstract : In this talk we consider structure-preserving model reduction of Hamiltonian systems, such that the reduced model is again a Hamiltonian system. We extend the classical linear-subspace model reduction methods, where the best possible error is bounded by the Kolmogorov N-width to reduced models constructed via nonlinear approximations. In this talk, we will particularly choose symplectic quadratic embeddings as our nonlinear approximation function.

MS [00793] SIAM Student Chapter Research Presentations

room : E818

• [03692] Differentially Private Confidence Interval for Extrema of Parameters
  • Author(s) :
    • Xiaowen Fu (Hong Kong University of Science and Technology)
    • Yang Xiang (Hong Kong University of Science and Technology)
    • Xinzhou Guo (Hong Kong University of Science and Technology)
  • Abstract : We aim to construct a valid and efficient confidence interval for the extrema of parameters under privacy protection. The usual statistical inference on the extrema of parameters often suffers from the selection bias issue, and the problem becomes more acute, as in many application scenarios of extrema parameters, we often need to protect the privacy of the data. In this work, we focus on the exponential family of distributions and propose a privatized parametric bootstrap method to address selection bias in the extrema of parameters problem under the scheme of differential privacy. While the usual privatized parametric bootstrap does not address selection bias appropriately, we prove that with a privatized bias correction term, the proposed parametric bootstrap method can lead to a valid and efficient confidence interval for the extrema of parameters. We illustrate the proposed method with the Gaussian case and regression case and demonstrate the advantages of the proposed method via numerical experiments and real data examples.
• [03749] Spherical signal processing via framelets and convolutional neural networks
  • Author(s) :
    • Jianfei Li (City University of Hong Kong)
  • Abstract : In this talk, we would like to introduce a general theoretical framework for constructing Haar-type tight framelets on any compact set with a hierarchical partition. In particular, we develop novel spherical framelets with directionality and combine them with CNNs for image denoising and inpainting tasks. The experiment results show that our proposed CNN model outperforms threshold methods.
• [03813] O(N) dense direct factorization with near-perfect weak scaling.
  • Author(s) :
    • Sameer Satish Deshmukh (Tokyo Institute of Technology)
    • Rio Yokota (Tokyo Institute of Technology)
    • George Bosilca (University of Tennessee at Knoxville)
  • Abstract : Approximating the off-diagonal blocks of dense matrices arising from the Boundary Element Method can reduce the time of a dense direct factorization from $O(N^3)$ to $O(N)$ with controllable error. Distributed factorization of such algorithms is challenging due to the presence of small, irregular computations. In this talk, we show how asynchronous execution can achieve good weak scaling on FUGAKU for a variety of Green's functions on a 2D geometry.
• [03907] Distributed Optimization with Imperfect Communication
  • Author(s) :
    • Jie Liu (City University of Hong Kong)
  • Abstract : In distributed optimization over multi-agent networks, each agent is endowed with a local private objective function. The purpose of distributed optimization is to minimize the sum of all agents' local objective functions cooperatively through information communication between different agents. However, the communication channels in the real life are not always perfect due to limited data rates, communication delays, noises, etc. In this presentation, we shall discuss distributed optimization with imperfect communication.

contributed talk: CT126

room : E820

[00788] Using multi-objective evolutionary algorithms when performing preventive maintenance actions

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E820
• Type : Industrial Contributed Talk
• Abstract : Maintenance has always been a key activity in the manufacturing industry, because of its economic consequences. Nowadays, its importance is increasing thanks to the ``Industry 4.0'' or the ``fourth industrial revolution'', which promotes automation through computer systems in manufacturing and aims to achieve intelligent or smart factory. There are more and more complex systems to maintain, and to keep all these devices in proper conditions maintenance management must gain efficiency and effectiveness. Within maintenance, Condition-Based Maintenance (CBM) programs can provide significant advantages, but it can be said that often these programs are complex to manage and understand, so several researches propose as simple as possible approaches that can be understood by users and modified by experts. With these context conditions, this paper focuses on CBM optimization in an industrial environment, with the objective of determining the optimal values of preventive intervention limits for equipment under corrective and preventive maintenance cost criteria. It develops a cost-benefit mathematical model that considers the evolution in quality and production speed, along with condition based, corrective and preventive maintenance. The cost-benefit optimization is performed using a Multi-Objective Evolutionary Algorithm. Both the model and the optimization approach are applied to an industrial case.
• Classification : 68W50, 68T20, 90C59
• Format : Talk at Waseda University
• Author(s) :
  • Eilsabete Alberdi (University of the Basque Country UPV/EHU)
  • Aitor Goti (University of Deusto)
  • Aitor Oyarbide-Zubillaga (University of Deusto)
  • Pablo Garcia-Bringas (University of Deusto)
  • Ana Sánchez (Polytechnic University of Valencia)

[00904] Quadrature Methods and Error Estimates for Particles in Stokes Flow

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E820
• Type : Contributed Talk
• Abstract : For axisymmetric particles in Stokes flow, boundary integral methods can be utilized for numerical evaluation of flow velocity on and outside particle surfaces. Precomputation yields a highly efficient and accurate quadrature by expansion $($QBX$)$ method for singular integrals when evaluating on-surface. For evaluation close to the particle surface $($nearly singular integrals$)$, a line interpolation method aided by quadrature error estimates is introduced and compared to QBX in terms of both accuracy and efficiency.
• Classification : 65Rxx, 65Dxx, 41Axx, 76-XX
• Format : Talk at Waseda University
• Author(s) :
  • Pritpal Matharu (KTH Royal Institute of Technology)
  • Anna-Karin Tornberg (KTH Royal Institute of Technology)

[02125] TNL: Numerical Library for Modern Parallel Architectures

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E820
• Type : Contributed Talk
• Abstract : TNL (www.tnl-project.org) is a collection of building blocks that facilitate the development of efficient numerical solvers and HPC algorithms. It is implemented in C++ using modern programming paradigms in order to provide a flexible and user-friendly interface similar to, for example, the C++ Standard Template Library. TNL provides native support for modern hardware architectures such as multicore CPUs, GPUs, and distributed systems, which can be managed via a unified interface. In our presentation, we will demonstrate the main features of the library together with efficiency of the implemented algorithms and data structures.
• Classification : 68W99, 68U01, 65N99, High-performance computing
• Format : Talk at Waseda University
• Author(s) :
  • Tomáš Oberhuber (Czech Technical University in Prague)
  • Jakub Klinkovský (Czech Technical University in Prague)
  • Radek Fučík (Czech Technical University in Prague)

[02201] Total Variation and Undecimated Wavelet Approach to Chest Radiograph Image Enhancement

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @E820
• Type : Contributed Talk
• Abstract : ABSTRACT Medical images are often corrupted by white noise, blurring and contrast defects. Consequently, important medical information may be degraded or completely masked. In this talk, I will discuss recent advances in the implementation of a total variation method and an undecimated wavelet image enhancing algorithm, as well as morphological techniques such as closing, thinning and pruning combined with wavelets methods, to improve the image quality and to extract target features from chest radiographs.
• Classification : 68U10, 44A20, 46N10, Chest radiograph image enhancement, mathematical morphology, wavelet decomposition
• Author(s) :
  • Anthony Y Aidoo (Eastern Connecticut State University)
  • Gloria Agyeiwaa Botchway (University of Ghana)
  • Matilda Acheampong Wilson (University of Ghana)

MS [02569] Quantification of Business Uncertainties through Industrial Mathematics

room : D101

• [03389] Mathematics behind performance estimation of multiscale structures
  • Format : Talk at Waseda University
  • Author(s) :
    • Yichao Zhu (Dalian University of Technology)
  • Abstract : In business involving commercial products carrying multiscale structures, utilisation of uncertainty quantification tools that are both reliable and efficient is still needy. In this talk, appropriate use of mathematical techniques of asymptotic analysis is proposed to resolve the issue. As an example, uncertain behaviours of fibre-reinforced composite laminates are considered. Through asymptotic analysis, it is shown that the building blocks of such thin plate configurations are two-dimensional slices, and analytical solutions are even available in the situation in consideration. Correlations between the confidence interval about the plate bending stiffness and manufactural uncertainties can then be established with relative ease.
• [04204] Handling Uncertainties in Decision Making
  • Format : Online Talk on Zoom
  • Author(s) :
    • ZAITUL MARLIZAWATI ZAINUDDIN (UTM CENTRE FOR INDUSTRIAL AND APPLIED MATHEMATICS (UTM-CIAM))
    • NORSHELA NOH (UNIVERSITI TUN HUSSEIN ONN MALAYSIA (UTHM))
    • ARIFAH BAHAR (UTM CENTRE FOR INDUSTRIAL AND APPLIED MATHEMATICS (UTM-CIAM))
  • Abstract : This study highlights the importance of incorporating uncertainty quantification of stochastic parameters in stochastic programming compared to expert judgement approach. It proposes a methodology for integrating stochasticity of input parameters into two-stage stochastic programming. The approach involves constructing a binomial scenario tree, which combines a binomial tree for each stochastic parameter and discretizes the continuous probability distribution of the underlying stochastic process. The scenario tree consists of all possible scenarios to explain future situations.
• [04896] Aggregation value regression and its application to household demand forecasting
  • Format : Talk at Waseda University
  • Author(s) :
    • Kei Hirose (Kyushu University)
    • Hiroki Masuda (University of Tokyo)
    • Hidetoshi Matsui (Shiga University)
  • Abstract : In recent years, a number of sensor data have been collected, and some researchers are interested in the aggregation values, such as congestion levels and electricity demand. This study constructs a regression modeling specifically designed for aggregation value forecasting. The proposed modeling is applied to household demand forecasting.

MS [00838] Perspectives in Artificial Intelligence and Machine Learning in Materials Chemistry, 2nd edition

room : D102

• [01431] Discovery of New Materials by Quantum Calculations and Artificial Intelligence
  • Format : Talk at Waseda University
  • Author(s) :
    • David Samuel Rivera Rocabado (Hiroshima University)
    • Mika Aizawa (Hiroshima University)
    • Takayoshi Ishimoto (Hiroshima University)
  • Abstract : Integrating artificial intelligence into real system first-principles calculations has the potential to transform the field of materials science and, ultimately, the world in which we live. In this presentation, the modeling and the prediction of the CO adsorption/activation on Ru nanoparticles exemplify that our new approach can be universally applied to predict the catalytic properties of any existing material and be used for the discovery of more functionalized materials.
• [05452] Causal analysis of materials functionality by combining topological data analysis and physical model
  • Format : Talk at Waseda University
  • Author(s) :
    • Masato Kotsugi (Tokyo University of Science)
  • Abstract : Microscopic image data is key to developing low-power, high-speed electronic devices. However, the complex interactions in nanoscale magnetic materials are difficult to understand. We developed a new functional design theory called “extended Landau free energy model” that combines persistent homology and machine learning with free energy to automate the interpretation of the microscopic image. This model illustrates the physical mechanism and critical location of magnetization reversal and proposes a device structure with low energy consumption.
• [05575] Machine learning for materials chemistry and chemical biology
  • Format : Talk at Waseda University
  • Author(s) :
    • Daniel Packwood (Kyoto University)
  • Abstract : This talk will review three recent success stories involving machine learning in materials science and chemistry: (1) the simulation of on-surface molecular self-assembly processes using machine-learned potentials and a novel genetic algorithm; (2) the design of a new organic semiconducting material with targeted band gap by a combination of unsupervised and supervised learning; (3) the prediction and verification of a new chemical compound for inducing cardiac tissue differentiation of stem cells.
• [01449] Topological descriptor of thermal conductivity in amorphous Si
  • Format : Online Talk on Zoom
  • Author(s) :
    • Emi Minamitani (Osaka University)
    • Takuma Shiga (AIST)
    • Makoto Kashiwagi (Aoyama Gakuin University)
    • Ippei Obayashi (Okayama University)
  • Abstract : In this talk, we analyze the relationship between the atomic configuration of amorphous Si and the thermal conductivity of the material. A topological descriptor constructed by persistent homology successfully predicts the thermal conductivity using machine learning, and from the machine learning model, we can extract medium-range order structures related to thermal conductivity using inverse analysis of persistent homology. https://doi.org/10.1063/5.0093441

contributed talk: CT137

room : D402

[00576] Modeling the Dispersion of Effluents Discharged into Tidally Coastal Waters

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D402
• Type : Contributed Talk
• Abstract : Mixing and dispersion of effluents discharged under the spring neap tidal oscillations are studied analytically on a flat seabed and a uniformly sloping bed. The solutions of two-dimensional advection-diffusion equations are presented graphically to visualize and analyze the spreading of effluent plumes in coastal waters, following discharges from a single sea outfall, multiple outfalls, and multiport diffusers, to showcase the model applications of marine outfall systems for disposal from industrial plants in the far field.
• Classification : 76Rxx, 35Q35, 76-10
• Format : Talk at Waseda University
• Author(s) :
  • Anton Purnama (Sultan Qaboos University)
  • Ahmed Al-Kasbi (University of Technology and Applied Sciences)

[01013] Satellite Data Assimilation through Community Land Model to improve Rice Crop Dynamics

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D402
• Type : Industrial Contributed Talk
• Abstract : The aim of the proposed talk is to discuss evaluation of existing form of Dynamic Generalized Vegetation Model (DGVM) of Community Land Model (CLM) in terms of its bio-geophysics and processes for major agro-ecosystems such as in rice-rice crop rotation in India. Development of new crop-specific growth modules to bring out new version of DGVM suitable for Indian sub-tropics will be explored. This will be followed by its evaluation with respect to surface fluxes. The new modelling system will represent explicit crop growth processes in a terrestrial ecosystem model operable in a stand-alone mode or embedded in a climate model equipped with satellite remote sensing-based data assimilation for large-area prediction of intra-seasonal and inter-annual variability of crop phenology, growth, yield and fluxes of energy, moisture and carbon in the rice based systems at regional scale.
• Classification : 76-10, 93-10, 68-XX
• Format : Talk at Waseda University
• Author(s) :
  • Mahesh Kumar (Sardar Vallabhbhai National Institute of Technology, Surat, India)
  • Ranjan Kumar Jana (Sardar Vallabhbhai National Institute of Technology, Surat, India)

[02477] Effect of contact angle hysteresis in a novel microfluidic system

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D402
• Type : Contributed Talk
• Abstract : We present a reduced ODE model, derived from a continuum framework, for fluid flow and solute transport in a novel microfluidic system with applications for drug discovery. While the flow is gravity-driven, our analysis highlights the importance of capillary effects, exploring how contact angle hysteresis and meniscus shape modify the flow. We show how our model can be used to identify optimal parameter regimes for advective solute transport, which informs device operation and design.
• Classification : 76-10, 76D45, 92-10
• Format : Talk at Waseda University
• Author(s) :
  • Barnum Swannell (University of Oxford)
  • Sarah Waters (University of Oxford)
  • James Oliver (University of Oxford)
  • Daniela Ortiz Franyuti (Roche Innovation Center)
  • Olivier Frey (InSphero)
  • Michal Rudnik (InSphero)

contributed talk: CT144

room : D403

[00339] Using Numerical Modeling two phase flow Method in evaporator design

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D403
• Type : Industrial Contributed Talk
• Abstract : Evaporator is a critical component in integration of simple cycle gas turbine into combined cycle power plant. Evaporator should be designed in accurate way depend on thermal parameters (gas & water). The method developed for design evaporator of Baiji gas power plant in Iraq. The method based on modeling tow phase flow by combination of three governing equations of energy conservation, Mass conservation and momentum conservation equation with numerical simulation using finite difference method.
• Classification : 80-xx, 80-10
• Format : Talk at Waseda University
• Author(s) :
  • Maher Saab Salamah (Ministry of Electricity / Iraq)

[01241] Crossing Sea States in Layered and Stratified Fluids

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D403
• Type : Contributed Talk
• Abstract : Crossing sea states are common phenomena in the oceans, and have been suggested as one possible generation mechanism for rogue waves. Modeling studies are conducted for (a) a two-layer fluid with long wave-short wave resonance, and (b) the triad resonance in a continuously stratified fluid with constant buoyancy frequency. Modulation instability will be enhanced. There is a preferred inclination of oblique wave propagation for a maximum growth rate, suggesting the occurrence of rogue waves.
• Classification : 76E30, 35Q35, 76-10
• Format : Talk at Waseda University
• Author(s) :
  • Qing Pan (The University of Hong Kong)

[00723] Density Maximum Effect on Natural Convection in a Porous Enclosure

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D403
• Type : Contributed Talk
• Abstract : The maximum density effect on natural convection in an enclosure filled with porous medium is numerically examined. One of the vertical walls is either fully or partially heated and various thermal boundary walls are considered for the cooling location. The nonlinear partial differential equations are solved by finite volume method together with power-law-scheme using SIMPLE algorithm. The qualitative results are expressed in the graphical form. The motivation for the study is the cooling of equipment.
• Classification : 80-XX, 80Axx, 80Mxx, 65Yxx, 76R10, 80 Classical thermodynamics, heat transfer
• Format : Talk at Waseda University
• Author(s) :
  • NITHYADEVI NAGARAJAN (Bharathiar University)

[02673] Reduced-order Modelling of Normal Elastohydrodynamic Collision of Spheres

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D403
• Type : Contributed Talk
• Abstract : I present a model for the normal impact of two elastic spheres colliding in incompressible constant-viscosity Newtonian fluid. Pressure is modelled by the Reynolds lubrication equation, and sphere deformation by Hertz contact theory. Modelling the radial pressure gradient by a Pad\'e approximant that is characterized by the centerline gap and curvature, and by rate of gap closing, the problem is reduced to a fourth-order system of ODEs that can be integrated numerically in time.
• Classification : 76Txx, 74Fxx, 70Gxx
• Format : Talk at Waseda University
• Author(s) :
  • John C. WELLS (Ritsumeikan University)

[02516] Stability and dynamics of multi-layer shear flow with liquid-liquid slip

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D403
• Type : Contributed Talk
• Abstract : Although the presence of slippage at polymer-polymer interfaces has been widely reported in experiments and MD simulations, its effect on the stability of superposed fluid layers undergoing shear has not been adequately addressed. Therefore, we formulate a mathematical model and under the assumption of one layer being asymptotically thin we derive a novel weakly non-linear evolution equation for the interface to study the linear stability and system dynamics. A slip-induced Turing-type instability is found.
• Classification : 76E17, 76E30, 76E05, 76D05
• Author(s) :
  • Anna Katsiavria (Imperial College London)
  • Demetrios Papageorgiou (Imperial College London)

contributed talk: CT151

room : D404

[02024] Quantum asymptotic phase function on the basis of Koopman operator theory

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D404
• Type : Contributed Talk
• Abstract : The asymptotic phase function is a fundamental quantity for analyzing classical limit-cycle oscillators. In this study, we define the asymptotic phase function for quantum nonlinear oscillators by using the eigenoperator of the Koopman operator associated with the fundamental oscillation frequency. In an example of a quantum van der Pol oscillator with a Kerr effect, we demonstrate that the proposed asymptotic phase appropriately yields isochronous phase values in both semiclassical and strong quantum regimes.
• Classification : 81-XX, 34L05, 92B25, Quantum synchronization, nonlinear dynamics, Koopman operator theory
• Format : Talk at Waseda University
• Author(s) :
  • Yuzuru Kato (Future University Hakodate)
  • Hiroya Nakao (Tokyo Institute of Technology)

[00978] Real-Time Krylov Theory for Quantum Computing Algorithms

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D404
• Type : Contributed Talk
• Abstract : Here we describe the variational quantum phase estimation (VQPE) method, a compact and efficient real-time subspace algorithm to extract eigenvalues using quantum hardware. We theoretically and numerically explore a generalized Krylov scheme where the Krylov subspace is constructed through a parametrized real-time evolution, applicable to the VQPE algorithm as well as others. We discuss its application to fundamental problems in quantum computation such as electronic structure predictions for strongly correlated systems.
• Classification : 81-08, 81-10
• Format : Talk at Waseda University
• Author(s) :
  • Katherine Klymko
  • Yizhi Shen (Massachusetts Institute of Technology )
  • Norm Tubman (NASA)

[01039] A model of cerebrospinal fluid flow in the cranial subarachnoid space

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D404
• Type : Contributed Talk
• Abstract : Cerebrospinal fluid fills the subarachnoid space (SAS), which covers the spinal cord and the brain. During the cardiac cycle, it pulsates due to time-varying brain displacements. In this work, we study oscillating and steady streaming flow in cranial SAS in order to understand the mixing processes and waste clearance. We develop a theoretical model of the flow using lubrication theory. The model suggests that steady streaming plays an important role in mixing.
• Classification : 76Z05
• Format : Talk at Waseda University
• Author(s) :
  • Mariia Dvoriashyna (University of Oxord)
  • Alain Goriely (University of Oxford)

[02506] Hydrodynamic hovering of swimming bacteria

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D404
• Type : Contributed Talk
• Abstract : The 'hovering' of flagellated bacteria near a rigid surface, i.e. stable swimming at a finite separation, has been studied experimentally and computationally but remains poorly understood physically. We use boundary element simulations to confirm existing results and to reveal that an elongated, as opposed to spherical, cell body is essential for hovering. We then derive and asymptotically solve a simplified model for the swimming cell and its near-field wall interactions, thereby elucidating the dominant physics.
• Classification : 76Z10, 92C17, 76M45
• Format : Talk at Waseda University
• Author(s) :
  • Pyae Hein Htet (University of Cambridge)
  • Debasish Das (University of Strathclyde)
  • Eric Lauga (University of Cambridge)

MS [00789] Algorithmic advances in computational quantum mechanics

room : D405

• [04860] Deterministic algorithms for the efficient evaluation of Feynman diagrams
  • Format : Talk at Waseda University
  • Author(s) :
    • Jason Kaye (Flatiron Institute, Simons Foundation)
    • Denis Golež (Jožef Stefan Institute)
    • Hugo U. R. Strand (Örebro University)
  • Abstract : The evaluation of Feynman diagrams is a fundamental computational task, and bottleneck, in Green's function methods for quantum many-body calculations. Mathematically, diagrammatic expressions take the form of high-dimensional integrals involving products of low-dimensional functions. Numerical methods for the efficient evaluation of these diagrams are predominantly based on Monte Carlo or quasi-Monte Carlo sampling. I will discuss recent progress in algorithms which exploit the structure of the diagrammatic expressions to obtain efficient deterministic algorithms. In particular, I will describe an algorithm for the evaluation of imaginary time diagrams based on sum-of-exponentials representations of Green's functions, and mention a related algorithm based on the decomposition of integrands into tensor trains using cross interpolation.
• [04522] Quantics tensor trains meet quantum physics
  • Format : Talk at Waseda University
  • Author(s) :
    • Hiroshi Shinaoka (Saitama University)
  • Abstract : In this talk, we apply quantics tensor train (QTT) to numerical simulations in quantum field theories$^1$. Using QTT, we compress space-time dependence of correlation functions and solve equations in the compressed form. We also introduce quantics tensor cross interpolation to enhance the power of QTT-based calculations$^2$. 1. H. Shinaoka et al., arXiv:2210.12984v2 (to appear in Phys. Rev. X), 2. M. K. Ritter et al., including H. Shinaoka, arXiv:2303.11819v2.
• [03608] Circuit Forms of Compressed Functions and Operators with Applications
  • Format : Talk at Waseda University
  • Author(s) :
    • Edwin Miles Stoudenmire (Flatiron Institute)
  • Abstract : Recently there has been growing interest in representing functions as tensor networks using the "quantized tensor train" format, which enables algorithms (integration, function optimization, ...) typically scaling logarithmically in the grid size. I will discuss techniques to construct functions and operators in this format using non-unitary analogues of quantum circuits. This leads to fast algorithms for Fourier and wavelet transforms, and has promising applications for systems of continuous variables in classical and quantum physics.
• [05166] Tensor-network sketching and many-body physics
  • Format : Talk at Waseda University
  • Author(s) :
    • Yuehaw Khoo (The University of Chicago)
    • Yoonhaeng Hur (The University of Chicago)
    • Yian Chen (The University of Chicago)
    • Jeremy Hoskins (The University of Chicago)
    • Michael Lindsey (UC Berkeley)
    • Edwin Miles Stoudenmire (Flatiron Institute)
  • Abstract : We study how a function can be estimated as a low-rank tensor-network from Monte-Carlo samples, without the use of optimization and without the curse of dimensionality. We demonstrate the usefulness in generative modeling and many-body physics.

MS [00140] Interacting particle systems: modeling, learning and applications

room : D407

• [03778] The mean-field limit of non-exchangeable integrate and fire systems
  • Format : Online Talk on Zoom
  • Author(s) :
    • Pierre-Emmanuel Jabin (Pennsylvania State University)
    • Datong Zhou (Pennsylvania State University)
  • Abstract : We investigate the mean-field limit of large networks of interacting biological neurons. The neurons are represented by the so-called integrate and fire models that follow the membrane potential of each neurons and captures individual spikes. However we do not assume any structure on the graph of interactions but consider instead any connection weights between neurons that obey a generic mean-field scaling. We are able to extend the concept of extended graphons, introduced in Jabin-Poyato-Soler, by introducing a novel notion of discrete observables in the system.
• [03624] Weak Form Equation Learning for Interacting Particle System Models of Collective Motion
  • Format : Online Talk on Zoom
  • Author(s) :
    • David Bortz (University of Colorado - Boulder)
    • Daniel Messenger (University of Colorado - Boulder)
  • Abstract : The Weak form Sparse Identification of Nonlinear Dynamics (WSINDy) methodology efficiently identifies governing equations from noisy data. We develop WSINDy for inference of 1st and 2nd-order IPS models as well as a joint model selection and classification method to both learn governing IPS equations and sort individuals into distinct interaction rule classes. We demonstrate the efficiency and proficiency of these methods on several test scenarios, motivated by common cell migration experiments.
• [03774] Mean-field nonparametric estimation of interacting particle systems
  • Format : Online Talk on Zoom
  • Author(s) :
    • Xiaohui Chen (University of Southern California)
    • Rentian Yao (University of Illinois at Urbana-Champaign)
    • Yun Yang (University of Illinois at Urbana-Champaign)
  • Abstract : This talk concerns the nonparametric estimation problem of the distribution-state dependent drift vector field in an interacting $N$-particle system. Observing single-trajectory data for each particle, we derive the mean-field rate of convergence for the maximum likelihood estimator (MLE), which depends on both Gaussian complexity and Rademacher complexity of the function class. In particular, when the function class contains $\alpha$-smooth Hölder functions, our rate of convergence is minimax optimal on the order of $N^{-\frac{\alpha}{d+2\alpha}}$. Combining with a Fourier analytical deconvolution estimator, we derive the consistency of MLE for the external force and interaction kernel in the McKean-Vlasov equation.
• [04754] Game-based learning of interaction rules for rational agents
  • Format : Online Talk on Zoom
  • Author(s) :
    • Mauro Bonafini (University of Verona)
    • Massimo Fornasier (Technical University of Munich)
    • Bernhard Schmitzer (University of Göttingen)
  • Abstract : We introduce novel multi-agent interaction models obtained as fast-reaction limits of evolutionary games. We discuss the well-posedness of these models and the learnability of individual payoff functions from observation data. We formulate the payoff learning as a variational problem, minimizing the discrepancy between the observations and the predictions by the payoff function. The abstract framework is fully constructive and numerically implementable. We illustrate this on computational examples.

contributed talk: CT157

room : D408

[02635] Application of mathematics in large-scale agriculture projects

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D408
• Type : Industrial Contributed Talk
• Abstract : Two large-scale projects, each involving a consorcium of breeding, growing and processing companies from potato industry in the Netherlands will be described, with the emphasis on the increasingly important role the mathematics is playing in these projects. Applied mathematics is required at the three major stages: design of experiments, data pre-processing, and association-regression studies. Successes and current challenges will be discussed.
• Classification : 92F05, 65Z05, 62J02, 62J05, 62J07, mathematics for agriculture
• Format : Talk at Waseda University
• Author(s) :
  • Neil Budko (Delft University of Technology)

[02389] Exploring the excess of cloud condensation nuclei and rain suppression using a minimal 3D Boussinesq model with bulk cloud microphysics

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D408
• Type : Contributed Talk
• Abstract : For many decades the hypothesis that an increase in air pollution could affect the rain formation processes has been discussed with theoretical, experimental, and numerical arguments. Several studies have shown that higher pollutant concentrations can inhibit, decrease or increase precipitation. Differences between results arise partly from the complexity of the problem, which requires the consideration of processes at multiple scales. This study aims to provide a very simple numerical model that satisfactorily represents the atmospheric dynamics and cloud microphysics to explore the effect of pollution on rain formation. We adapted and extended a previously existing three-dimensional minimal model consisting of five equations describing the atmospheric dynamics and implemented a simple bulk parametrization that represents the role of cloud condensation nuclei (CCN) 's role in cloud formation processes. To explore the effect of different CCN concentrations and distributions, we used two CCN profiles, one with a single accumulation layer and one with two layers, modifying their concentrations. Our results showed that polluted scenarios resulted in rain inhibition when a single CCN layer was initially present and rain increment when two layers were present. In low-polluted environments, both CCN initial profiles generated similar precipitation and showed similar dynamic patterns. In this talk, we will highlight the importance of the vertical distribution of CCN, not only concentration, on the formation of rain, its inhibition, or suppression. This is joint work with Olmo Guerrero Medina.
• Classification : 86A08, 35Q86
• Format : Talk at Waseda University
• Author(s) :
  • Gerardo Hernandez-Duenas (National Autonomous University of Mexico, Institute of Mathematicas)
  • Olmo Guerrero-Medina (University of California Davis)

[02554] Domain-invariant subcell-based blending limiter for Lax-Wendroff Flux Reconstruction

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D408
• Type : Contributed Talk
• Abstract : Lax-Wendroff flux reconstruction (LWFR) is a single-step, arbitrarily high order, quadrature free method for solving hyperbolic conservation laws. We propose a subcell-based blending scheme for LWFR. By using MUSCL-Hancock reconstruction on the subcells and Gauss-Legendre points in flux reconstruction, we improve small-scale resolution compared to the subcell-based RKDG scheme of Henneman et al. $($2020$)$. We also propose a cost-effective correction to obtain a provably domain-invariant Lax-Wendroff scheme. Efficient Julia implementation will be discussed.
• Classification : 76M10, 76M12, 76-04, 35L65
• Format : Talk at Waseda University
• Author(s) :
  • Arpit Babbar (Tata Institute of Fundamental Research - Centre for Applicable Mathematics (Bangalore))
  • Praveen Chandrashekar (Tata Institute of Fundamental Research - Centre for Applicable Mathematics (Bangalore))
  • Sudarshan Kumar Kenettinkara (School of Mathematics, Indian Institute of Science Education and Research)

contributed talk: CT158

room : D501

[01182] Optimizing the manufacturing process of a cutting machine in iron industry

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D501
• Type : Contributed Talk
• Abstract : In this talk we discuss a multi-criteria optimization framework designed for the cooperation with a prominent company, leader in the production of automatic machines employed in iron manufacturing. The optimized machine process counts several steps, starting by cutting the bars at specified lengths and moving them into two temporary buffers. Afterwards, bars are relocated through pliers to parallel depots through a lengthwise movement and gathered by order to facilitate the subsequent transfer to downstream steps.
• Classification : 90-08, 90-10, 90-04
• Format : Talk at Waseda University
• Author(s) :
  • Andrea Pizzuti (Università Politecnica delle Marche)
  • Fabrizio Marinelli (Università Politecnica delle Marche)

[00765] V-KEMS: Tackling industrial and COVID problems via virtual study groups

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D501
• Type : Industrial Contributed Talk
• Abstract : During the pandemic a group of UK mathematicians formed the Virtual Forum for Knowledge Exchange in the Mathematical Sciences (V-KEMS). This ran many online virtual study groups (VSGs), using mathematics to tackle urgent societal challenges. These varied from keeping shops, workplaces, and universities safe, to advising the transport, healthcare, and leisure industries. VSGs were so effective that they informed government policy. My talk will describe how VSGs work, and plans for their future development.
• Classification : 90-10, 35Mxx, 34Fxx
• Format : Talk at Waseda University
• Author(s) :
  • Chris Budd (University of Bath)

[00954] Dynamic Modeling and Optimization of Mixed Hydrogen-Natural Gas Flow in Pipeline Networks

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D501
• Type : Contributed Talk
• Abstract : We present a dynamic model for the mixing and transport of hydrogen-natural gas blends in a pipeline network. The dynamic model is derived by lumping the partial differential equations to yield a differential algebraic system. The derived system accommodates spatio-temporally heterogeneous gas injections, and is more complex and numerically ill-conditioned than the case of a single gas. Multiple reformulations for the nonlinear and non-smooth equations of mixing are compared using standard optimization solvers.
• Classification : 90-10, 37N40, 90C30, Dynamic and Nonlinear Programming
• Format : Talk at Waseda University
• Author(s) :
  • Saif Kazi (Los Alamos National Laboratory)
  • Anatoly Zlotnik (Los Alamos National Laboratory)
  • Kaarthik Sundar (Los Alamos National Laboratory)
  • Shriram Srinivasan (Los Alamos National Laboratory)

[02512] Incentive design for electric vehicles charging station management

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D501
• Type : Contributed Talk
• Abstract : We propose a new bilevel optimization model to determine optimal pricing of Electric Vehicle (EV) changing stations. The goal is to define incentives to decrease the energy grid peaks while integrating the behaviour of the EV users through preference lists. The bilevel optimization model is reformulated as a single level one based on a rank pricing approach. The model is solved through a cutting plane approach. Numerical results are discussed
• Classification : 90-10, 90c11
• Format : Talk at Waseda University
• Author(s) :
  • Luce Brotcorne (INRIA)
  • Luce Brotcorne (INRIA)
  • Miguel Anjos (University of Edinburgh)
  • Gaël Guillot (INRIA)

[02468] Intuitionistic fuzzy proximal twin svm with fuzzy hyperplane

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D501
• Type : Contributed Talk
• Abstract : Twin support vector machine (TWSVM) is a contemporary machine learning technique for classification and regression problems. However, TWSVM is sensitive to noises as it ignores the positioning of the input data samples and hence fails to distinguish between support vector and noises. To overcome this issue, we propose a novel Intuitionistic fuzzy proximal twin svm with fuzzy hyperplane (IFTPSVM-FH). Instead of addressing two quadratic programming problems like in TWSVM, two non-parallel classifiers are obtained by solving two systems of linear equations which makes the model more efficient. The two major features of the proposed approach are that it gives an intuitionistic fuzzy number based on the relevance to each data vector and that the parameters for the hyperplane, such as the components of the normal vector and the bias term, are fuzzified variables. With the use of fuzzy variables, the proposed fuzzy hyperplane effectively captures the ambiguous character of real-world categorization tasks by representing vagueness in the training data. The proposed approach uses local neighbourhood information among the data points and also uses both membership and non-membership weights to reduce the effect of noise and outliers. By incorporating nonlinear kernel functions into the feature space, the method can be used to detect complex patterns or non-linearity in the dataset. We have applied our method on real-world classification tasks and concluded that it performs incredibly well in comparison to other approaches. In order to demonstrate the practical application of the proposed model, we use it for the predict the trends of the stock market.
• Classification : 90-08, 90C30, 90C25
• Format : Online Talk on Zoom
• Author(s) :
  • Yash Arora (IIT Roorkee)
  • Shiv Kumar Gupta (IIT Roorkee)

contributed talk: CT159

room : D502

[02513] Models for the Interdiction Problem for the Minimum Spanning Tree

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D502
• Type : Contributed Talk
• Abstract : The Minimum Spanning Tree Interdiction (MSTI) problem is a two-player game between a network operator aiming to determine a Minimum Spanning Tree (MST) and an interdictor which, constrained by a budget, changes the network topology to increase the weight of a MST. Mathematical formulations for a generalization of the MSTI problem are devised, and valid inequalities are proposed. Dominance relations between the models are studied, and computational experiments are presented to evaluate their efficiencies.
• Classification : 90-10, 90C10, 90C46, Bilevel programming
• Format : Talk at Waseda University
• Author(s) :
  • Luis Salazar-Zendeja (INRIA)
  • Diego Cattaruzza (Centrale Lille)
  • Martine Labbé (Université Libre de Bruxelles)
  • Frédéric Semet (Centrale Lille)

[00070] SDDS-SABC based Algorithm for solving non-linear optimization problems

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D502
• Type : Contributed Talk
• Abstract : Optimizing complex non-linear constrained optimization problems is often a challenging task. This work proposes a new hybrid method called SDDS-SABC based on the Split-Detect-Discard-Shrink technique and Sophisticated ABC algorithm to optimize the said problems. The SDDS method is responsible for shrinking the full search region through a recursive breakdown and improves computational effort to focus on the subregion covering potential solutions for further decomposition. SABC plays a vital role in extracting the best solutions from the subregions whose values help detect the promising subregion. Both SDDS and SABC are sequentially repeated until the region reduces to a nominal width representing the optimization problem's global/ close to global solution(s). The Ranking and selection rules have been applied to assist optimistic decision-making with an attitude to discard the subregion covering non-promising solution (s). At the same time, the subregion with a promising solution is accepted as the current shrink region for a further split. We introduce a new initialization scheme for food sources in the SABC algorithm, which excels the existing initialization process. Develop Dual-strategy Employed bee's phase, allowing bees to split into two groups and use their respective group strategies to explore their neighbourhood while maintaining their collaborative contribution. We also introduce a new Dynamic penalty method that is free from extra parameters or factors like most existing penalty methods do to improve the optimization efficiency. To check the validity of SDDS-SABC, we have applied it to benchmark functions and engineering problems. To measure our proposed method's statistical significance against other existing heuristic optimization methods, we carried out the non-parametric Friedman and Wilcoxon rank tests.
• Classification : 90-xx, 90-08, 90-10, optimization algorithms
• Format : Online Talk on Zoom
• Author(s) :
  • Dhirendra Sharma (Birla Institute of Technology Mesra, Ranchi)
  • Darakhshan Jabeen Syeda (Birla Institute of Technology Mesra, Ranchi)

[00762] On the dissolution of particles subject to natural convection

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D502
• Type : Contributed Talk
• Abstract : The dissolution of a solid spherical particle is a canonical problem that finds many areas of application, including the pharmaceutical industry. In this work, we provide a generalized theory that tackles the role of natural convection in the surrounding dissolving medium. We investigate its effects on hydrodynamics and how it interacts with the diffusion during dissolution to deform the particle geometry whilst altering the release profile of pharmaceutical ingredients, a key aspect in drug delivery.
• Classification : 76-10, 76R10, 76R50
• Format : Talk at Waseda University
• Author(s) :
  • Milton Assunção (University of Limerick)
  • Michael Vynnycky (University of Limerick)
  • Kevin Moroney (University of Limerick)

[00440] SIMULATION OF SHALLOW WATER EQUATIONS WITH DEPTH PERTURBATIONS AND WITH AND WHITHOUT THE CORIOLIS EFFECT

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D502
• Type : Contributed Talk
• Abstract : Shallow water equations are a system of partial differential equations that describe the superficial layer of a fluid with hydrostatic equilibrium derived from the Navier-Stokes equations which are used to describe fluid movements based on characteristics such as density, etc. We perform simulations of the evolution of water surface with various bottom variations, with and without the Coriolis effect using finite differences to analyze and understand how these variations affect the fluid dynamics.
• Classification : 76-02, 76-05, 76-10, 68R99
• Format : Talk at Waseda University
• Author(s) :
  • Daniel Francisco Sanabria Bernal (Universidad Militar Nueva Granada)
  • Maria Isabel Romero Rodriguez (Universidad Militar Nueva Granada)

contributed talk: CT161

room : D505

[01607] AN INVENTORY MODEL WITH PRICE- AND STOCK-DEPENDENT DEMAND

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D505
• Type : Contributed Talk
• Abstract : In this paper, we develop a multi-item inventory model with price- and stock-dependent demand and backorder. The decision variables in the model are the cycle length and the time when inventory drops to zero. The purpose of the model is minimizing the total inventory cost. Comparisons among alternative replenishment policies such as individual order, joint order or combination between these two policies are also considered. Numerical experiments and sensitivity analysis are also given.
• Classification : 90B05, 91B06, 91B02, Inventory models
• Format : Talk at Waseda University
• Author(s) :
  • Dharma Lesmono (Universitas Katolik Parahyangan)
  • Taufik Limansyah (Universitas Katolik Parahyangan)
  • Ignasius Sandy (Universitas Katolik Parahyangan)

[00224] Multi-objective multi-route STP with carbon emission and risk mitigation in Pharmaceutical Supply Chain under Pythagorean fuzzy Environment

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D505
• Type : Industrial Contributed Talk
• Abstract : This research proposes multi-objective multi-route fixed-charge solid transportation problem with carbon emission and risk mitigation in Pharmaceutical Supply Chain (PSC) under trapezoidal Pythagorean fuzzy environment. A novel ranking index is proposed to convert the suggested Pythagorean fuzzy model into its deterministic version. This study develops new computational procedure to minimize the chosen factors in PSC. Thereafter the model is solved by intuitionistic fuzzy and hybrid programming. Finally, an example is included to show the effectiveness of the model.
• Classification : 90B06, 90B50, 90C29, 90C70
• Format : Talk at Waseda University
• Author(s) :
  • Dr. Sankar Kumar Roy (Dept. of Applied Mathematics, Vidyasagar University, Midnapur-721102, West Bengal, India)

[00557] Three dimensional laminar flow in a dividing channel

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D505
• Type : Contributed Talk
• Abstract : This talk will describe a mathematical-modelling study concerned with fluid flow within a channel using asymptotic methods to study fluid behaviour on long axial length scales. Although many 3D problems can be solved through direct numerical simulations, it is generally useful to verify them with concrete analytical theory, which this study aims to do. Motivations for this research relate to providing insights into branching flows for cardiovascular vessels, industrial problems and Hele-Shaw cells.
• Classification : 76-10, 76d10, 76D27
• Format : Talk at Waseda University
• Author(s) :
  • Thuy Duong Dang (University College London)
  • Frank Smith (University College London)
  • Christian Klettner (University College London)

[00885] Hybrid nanofluid of Heimenz flow over electromagnetic surface: Enhancement in thermal energy

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @D505
• Type : Industrial Contributed Talk
• Abstract : Over decades, the Hiemenz flow for heat transfer mechanism has gained a lot of significant consideration from engineers and researchers owing to the optimal rates of heat transfer, pressure and mass deposition near stagnation point in high speed flows. The stagnation region flows, initiated by Hiemenz [1], are very frequent and extensively adopted for modeling in considerable fields, such as micro cooling systems, extrusions with a die, continuous casting, jet impingements, and-so-forth. The novel and advanced concepts of nanofluids offer fascinating heat transfer characteristics compared to conventional heat transfer fluids. Applications of nanofluids in industries such as heat exchanging devices, cool automobile engines and welding equipment and to cool high heat-flux devices such as high power microwave tubes and high-power laser diode arrays. Hybrid nanofluids can also effectively be used for a wide variety of industries, ranging from transportation to energy production and in electronics systems like microprocessors, drug distributors to check the chemical reactions of drugs in blood, as coolants and heat exchangers for better heat transfer, as lubricators, in nuclear reactors for thermal emission and absorption, solar concentrators for absorbing much of the solar radiation, and many more. The objective of this study to improve the heat transfer rate by solving Hiemenz flow of hybrid nanofluid over an electromagnetic surface.
• Classification : 76-10, Heat transfer
• Format : Online Talk on Zoom
• Author(s) :
  • Islam Zari (University of Peshawar)
  • Karlygash Dosmagulova (Ghent University, Belgium)
  • Chinwendu Emilian MADUBUEZE (Federal university of Agriculture Makurdi Nigeria )

MS [00935] Applied mathematics in industry: Success stories of collaboration between academia and industry in Mexico

room : D515

• [01598] Public Transportation in Mexico
  • Format : Online Talk on Zoom
  • Author(s) :
    • Yasmin Rios Solis (Tecnológico de Monterrey)
  • Abstract : Mexican public transportation planning and operation need different mathematical models than the ones used in developed countries. Indeed, planning stages like timetables and frequency setting should be revisited weekly or even daily. I will present two case studies of companies in Mexico and the main points that differentiate the classical models in the scientific literature from the needed ones. In particular, we will talk about the timetabling problem together with the vehicle scheduling problem to minimize the number of unfulfilled trips. I will present the models, the real case, and computational experimentation.
• [01632] Successful cases of mathematical applications for business
  • Format : Talk at Waseda University
  • Author(s) :
    • Ivete Sanchez-Bravo (Centro de Investigación en Matemáticas)
  • Abstract : Science and technology are two key elements for the development of all countries. The industrial sector seeks to apply frontier knowledge to generate value in its processes and products, so it needs a translation to apply it, in addition to having personnel trained in these topics. This talk will present the results and successful partnerships between some Mexican and multinational companies, as well as some initiatives such as workshops for companies to encourage teamwork, organized by CIMAT with other institutions specifically in areas of Applied Mathematics, such as AI, Optimization, and Data Science.
• [01653] Statistical Methods for Natural Disaster Risk Assessment
  • Format : Online Talk on Zoom
  • Author(s) :
    • Ramses H Mena (UNAM)
  • Abstract : The study and risk assessment of natural disasters are of crucial interest for every country. The ability to foresee potencial losses are of paramount importance for emergency policies, prevention, reconstruction and risk transfer mechanisms. Using a case study with the Mexican Natural Disasters Fund (FONDEN), we will discuss the importance of statistical and probabilistic methodologies created to aid the insurance against natural disasters.
• [01743] Collaboration between SMM and mathematical professionals in the mexican industry
  • Format : Talk at Waseda University
  • Author(s) :
    • Giovana Ortigoza Alvarez (Seguros Monterrey New York Life)
  • Abstract : The collaboration between mathematics graduates in Mexico and the Mexican Mathematical Society (SMM) has been of vital importance and a topic of interest in recent years. Since 2016, through special sessions in the national congress that the (SMM) organizes each year, talks, panel discussion and workshops focused on the empowerment of mathematicians and the collaborations that can be developed in the private industry in Mexico are presented. In this talk we will talk about this project.

contributed talk: CT166

room : A201

[02298] New semidefinite relaxations for a class of complex quadratic programming problems

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A201
• Type : Contributed Talk
• Abstract : In this talk, we propose some new semidefinite relaxations for a class of nonconvex complex quadratic programming problems, widely appear in signal processing and power system. By deriving new valid constraints to the matrix variables in the lifted space, we derive some enhanced semidefinite relaxations of complex quadratic programming problems. Then, we compare the proposed semidefinite relaxations with existing ones, and show that the newly proposed semidefinite relaxations could be strictly tighter than the previous ones. Numerical results indicate that the proposed semidefinite relaxations not only provide tighter relaxation bounds but also improve some existing approximation algorithms by finding better sub-optimal solutions.
• Classification : 90C20, 90C22, 90C35
• Format : Talk at Waseda University
• Author(s) :
  • Zhibin Deng (University of Chinese Academy of Sciences)
  • Yinzhe Xu (North China Electric Power University)
  • Cheng Lu (North China Electric Power University)
  • Yafeng Liu (Chinese Academy of Sciences)

[01034] Machine Learning for Two-stage Robust Optimization

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A201
• Type : Contributed Talk
• Abstract : When dealing with problems under uncertainty, two-stage robust optimization is one of the key approaches: you obtain an optimal robust solution, and adapt to the real scenario. However, these problems are one of the hardest optimization problem classes. To accelerate finding high-quality solutions, we propose a machine learning-based strategy. We experimentally show that with using our strategy you can train based on small problems, and apply them to bigger problems, while still getting good results.
• Classification : 90C17, 90C90
• Format : Talk at Waseda University
• Author(s) :
  • Esther Julien (Delft University of Technology)
  • Krzysztof Postek (Delft University of Technology)
  • Ilker Birbil (University of Amsterdam)

[02443] Enhanced charge-based algorithm and its application in reliability-redundancy allocation problems

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A201
• Type : Contributed Talk
• Abstract : Reliability-redundancy allocation problems (RRAP) require selecting components with diverse choices and redundancy levels that maximize profit within constraints. The nonlinearity and non-smoothness in RRAP have defeated many traditional mathematical approaches. Therefore, in this paper, a new version of the charge-based artificial electric field algorithm (AEFA) is proposed, incorporating a novel Coulomb's constant and bounds. This restructuring improves the adaptability of AEFA on RRAPs. The suggested algorithm outperforms other existing algorithms on seven RRAPs.
• Classification : 90C15, 90B25, 90C29, 90C06, 90C26
• Author(s) :
  • Dikshit Chauhan (Dr B R Ambedkar National Institute of Technology Jalandhar)
  • Anupam Yadav (Dr B R Ambedkar National Institute of Technology Jalandhar)

[02511] Autocratic Decision-Making based on Neutrosophic Sets for Machine Selection in the Industrial Factories

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A201
• Type : Industrial Contributed Talk
• Abstract : Neutrosophic Sets address ambiguity by considering the levels of truth, falsity, and indeterminacy. This research proposes an autocratic strategy for dealing with Multi-Attribute Decision-Making problems in the neutrosophic environment. The method is adopted to handle machine selection problems to stimulate both production level and income creation, in which executives utilize neutrosophic values to estimate the determination levels of the characteristics. Analytical examinations demonstrate that the offered approach is more efficient than the other existing methods.
• Classification : 90B50, 65Kxx
• Format : Talk at Waseda University
• Author(s) :
  • Amirhossein Nafei (National Taipei University of technology, Taipei , Taiwan )
  • Seyed Hadi Nasseri Ojaki (Department of mathematics, University of Mazandaran, Babolsar, Iran )

[02652] A multi-parametric approach for solid transportation problem under uncertainty conditions

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A201
• Type : Contributed Talk
• Abstract : Since most real-life issues take place in an imprecise environment, the uncertain parameters of models based on these issues are also more realistic. In the meantime, transportation issues are no exception. Uncertainty in solid transportation problems is one of the most important issues of the economy of each country and one of the applied issues in operations research too. In this research, we present a new two-phase approach based on the parametric method for solving solid transportation problem with fuzzy objective coefficients and flexible constraints. In this method, better use of resources is done, and it achieved the maximum satisfaction level.
• Classification : 90B50
• Author(s) :
  • Seyed Hadi Nasseri Ojaki (Department of Mathematics Department of applied mathematics, University of Mazandaran )
  • Amirhossein Nafei (National Taipei University of technology, Taipei , Taiwan )
  • Seyedeh Zehra Nasseri Ojaki (Department of Computer Engineering, Noshirvani University of Technology, Babol, Iran )

contributed talk: CT168

room : A206

[00912] Simulation-based Bayesian optimization over categorical covariates

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A206
• Type : Contributed Talk
• Abstract : Optimizing black-box functions of categorical variables has important applications, including the design of biological sequences with specific properties. Bayesian optimization is widely used in this type of problem. It involves adjusting a probabilistic machine learning model of the objective and using an acquisition function to guide the optimization process. We propose a new algorithm to sequentially optimize the acquisition function inspired in simulated annealing. We address convergence issues and demonstrate its effectiveness on RNA-sequence optimization.
• Classification : 90C27, 62F15, 60J20
• Format : Talk at Waseda University
• Author(s) :
  • Roi Naveiro (CUNEF University)

[02102] Network Construction Problems

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A206
• Type : Contributed Talk
• Abstract : Network construction problems seek to find efficient schedules of constructing edges of a new transportation network under limited resources, with the goal of minimizing a scheduling objective which is a non-decreasing function of the times when some important pairs of nodes become connected. The talk will discuss some recent results in this area of combinatorial optimization, focusing on classification and computational complexity.
• Classification : 90C27
• Format : Talk at Waseda University
• Author(s) :
  • Igor Averbakh (University of Toronto)

[01621] A Case Study on Multi-objective Fixed-charge Transportation Problem

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A206
• Type : Contributed Talk
• Abstract : This paper investigates a case study in the field of transportation and proposes an approach for the Pareto-optimal solution of the multi-objective fixed-charge transportation problem with real life parameters represented as uncertain numbers. The model includes the knowledge and agreement as well as difference in judgements of all the experts involved. Three approaches, viz, goal programming, weighted-sum method and the fuzzy programming technique are extended using AHP, and the obtained results are analyzed and discussed.
• Classification : 90C29, 90C70, 90B06, 90-10
• Author(s) :
  • Deepika Rani (Dr B R Ambedkar National Institute of Technology Jalandhar (INDIA))
  • Shivani Saini (National Institute of Technology Jalandhar (INDIA))

[01223] Descent hybrid four-term conjugate gradient methods for unconstrained optimization

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A206
• Type : Industrial Contributed Talk
• Abstract : Conjugate gradient method (CGM) is widely acclaimed to be efficient for solving large-scale unconstrained optimization problems. This study proposes new modified schemes that contain four terms based on the linear combination of the update parameters of classical or early methods depending on the popular two- and three-term CGMs. Hybridized methods have been found to exhibit better performance than the classical methods (Stanimirovic et al., 2018). Several other methods in this category can be found in (Adeleke et al., 2018; Osinuga and Olofin, 2018; Stanimirovic et al., 2018). In continuation of the previous results, we propose hybrid methods for the solution of large-scale unconstrained optimization problems as motivated and inspired by (Alhawarat et al., 2021, Yao et al.,2020, Stanimirovic et al.,2018). Modified methods are defined using appropriate combinations of the search directions and included parameters. In this case, our methods are hybridizations of HS and DY methods. In addition, we propose a class of Dai-Liao CGMs developed using new search directions developed using different values of included parameter. Under some certain assumptions, descent and convergence properties were established with the underlying strong Wolfe line search. The results of the new schemes showed superior performance over the existing ones in the sense of performance profiles of Dolan and More (2002). Keywords: unconstrained optimization, strong Wolfe line search, descent property, global convergence. AMS subject classification. 49J52, 49J53, 90C30 References [1] Adeleke, O. J., Osinuga, I. A. and Raji, R. A. 2021 A globally convergent hybrid FR-PRP conjugate gradient method for unconstrained optimization problems, WSEAS Transactions on Mathematics, 20, 736 -744, DOI: 10.37394/23206.2021.20.78. [2] Alhawarat, A., Alhamzi, G., Masmali, I. and Salleh, Z. 2021 A descent four-term conjugate gradient method with global convergence properties for unconstrained optimization problems, Mathematical Problems in Engineering, Volume 2021, Art. ID. 6219062, 14 pp. [3] Dai, Y. H. and Liao, L. Z. 2001 New conjugacy conditions and related nonlinear conjugate gradient methods, Applied Mathematics and Optimization, 43 (1), 87 – 101. [4] Dolan, E. and More, J. J. 2002 Benchmarking optimization software with performance profile, Mathematical Programming, 91, 201 – 213. [5] Osinuga, I. A. and Olofin, I. O. 2018 Extended hybrid conjugate gradient method for unconstrained optimization. Journal of Computer Science and its Applications, 25 (2); 166–175 [6] Stanimirovic, P. S., Ivanov, B, Djorjevic, S. and Brajevic, I. 2018 New hybrid conjugate gradient and Broyden-Fletcher-Goldfarb-Shanno conjugate gradient methods, Journal of Optimization Theory and Applications, DOI: 10.1007/s10957-018-1324-3 [7] Yao, S., Ning, L., Tu, H. and Xu, J. 2020 A one-parameter class of three-term conjugate gradient methods with an adaptive parameter choice, Optimization Methods and Software, 35 (6), 1051-1064.
• Classification : 90C30, 65K05, 90C26, Nonlinear Optimization
• Format : Online Talk on Zoom
• Author(s) :
  • Idowu Ademola Osinuga (Federal University of Agriculture, Abeokuta, Nigeria )
  • Moses Oluwasegun Olubiyi (Federal University of Agriculture, Abeokuta)
  • Semiu Akinpelu Ayinde (Babcock University, Ilishan-Remo)

MS [02012] Splitting Optimization: Theory, Methodology and Application

room : A207

• [02918] A trust-region-based splitting method for linear constrained programs
  • Format : Talk at Waseda University
  • Author(s) :
    • Deren Han (Beihang University)
  • Abstract : The augmented Lagrangian based splitting methods have found more and more applications in scientific and engineering computation, such as compressive sensing, covariance selection, image processing and transportation research. One of the basic difficulties in such algorithms is the selection of the parameter in the augmented Lagrangian function, a larger one may make the primal progress too small while a small one may slow down the dual progress. To overcome this difficulty, in this paper, we propose to solve the splitting subproblems in a trust-region manner, and the radius can be adjusted smartly. Under the same mild conditions as those for classical augmented Lagrangian based splitting methods, we prove the global convergence of the proposed algorithm. Moreover, the $\mathcal{O}(1/\epsilon)$ convergence rate is also analyzed in an ergodic sense. We present some preliminary numerical experiments on medical image recovery and traffic assignment, which show that the trust-region-based splitting method is efficient and promising.
• [02995] A Decentralized Second-Order Multiplier Algorithm with Quasi-Newton Tracking
  • Format : Talk at Waseda University
  • Author(s) :
    • Liping Wang (Nanjing University of Aeronautics and Astronautics)
  • Abstract : In this talk, we consider a decentralized optimization problem of minimizing a finite sum of strongly convex and twice continuously differentiable functions over a fixed connected undirected network. We propose a fully decentralized second-order multiplier algorithm (DSOM) where second-order information are approximated by simple algebraic calculations and at most matrix-vector products. It is the first work to study the second-order multiplier method in decentralized optimization which is equivalent to the primal-dual method with twice primal quasi-Newton steps and once dual BB step per iteration. Additionally, in DSOM the local direction on each node asymptotically approximates the global quasi-Newton direction. Under some mild assumptions, the proposed algorithm is illustrated to have global linear convergence rate. Numerical results are also reported for verifying its effectiveness.
• [03066] Tight Convergence Rate in Subgradient Norm of the Proximal Point Algorithm
  • Format : Talk at Waseda University
  • Author(s) :
    • Guoyong Gu (Nanjing University)
    • Junfeng Yang (Nanjing University)
  • Abstract : Proximal point algorithm has found many applications, and it has been playing fundamental roles in the understanding, design, and analysis of many first-order methods. In this paper, we derive the tight convergence rate in subgradient norm of the proximal point algorithm, which was conjectured by Taylor, Hendrickx and Glineur $[$SIAM J. Optim., 27 (2017), pp. 1283--1313$]$.
• [03073] A fast PIRNN algorithm for nonconvex low-rank matrix minimization problems
  • Format : Talk at Waseda University
  • Author(s) :
    • Zhili Ge (Nanjing Normal University of Special Education)
  • Abstract : In this paper, we propose a fast PIRNN algorithm with extrapolation for solving a class of nonconvex low-rank matrix minimization problems. The proposed method incorporates two different extrapolation steps with respect to the previous iterations into the backward proximal step and the forward gradient step of the classic proximal iteratively reweighted method. We prove that the proposed method generates a convergent subsequence under general parameter constraints, and that any limit point is a stationary point of the problem. Furthermore, we prove that if the objective function satisfies the KL property, the algorithm is globally convergent to a stationary point of the considered problem. Finally, we perform numerical experiments on a practical matrix completion problem with both synthetic and real data, the results of which demonstrate the efficiency and superior performance of the proposed algorithm.

MS [01036] Progress in Mathematical Programming Methods and Applications

room : A208

• [05524] Progress in Mathematical Programming Solvers from 2001 to 2020 and future Challenges
  • Format : Talk at Waseda University
  • Author(s) :
    • Thorsten Koch (Technische Universität Berlin / Zuse Institute Berlin)
  • Abstract : We investigate the progress made in LP and MILP solver performance during the last two decades. On average, we found that for solving LP/MILP, the total speed-up was about 180 and 1,000 times, respectively. However, these numbers considerably underestimate the progress made on the algorithmic side: many problem instances can nowadays be solved within seconds, which the old codes are not able to solve within any reasonable time. Finally, we will comment on future developments.
• [02270] Steepest-Edge Simplex Algorithms for Quadratic Programming
  • Format : Talk at Waseda University
  • Author(s) :
    • Shoji Shimizu (NTT DATA Mathematical Systems Inc.)
    • Koichi Fujii (NTT DATA Mathematical Systems Inc.)
    • Julian Hall (University of Edinburgh)
  • Abstract : We present steepest-edge simplex algorithms for quadratic programming problems. It is well known that in linear programming problems, the steepest-edge rule or Devex rule greatly reduces the total number of iterations in the simplex method. We extend these rules to the simplex method for quadratic programming and show their effectiveness through numerical experiments.
• [02259] Techniques and advances for solving MINLPs
  • Format : Talk at Waseda University
  • Author(s) :
    • Robert Luce (Gurobi)
  • Abstract : We consider solving mixed-integer nonlinear optimization problems to global optimality. Our solver is based on the common branch-and-bound paradigm, but includes a number of specialized techniques to deal with nonconvex constraints and nonconvex objective functions. In this talk we will outline a few of these components from a theoretical and computational point of view.
• [05560] News from the FICO Xpress MIP Solver and Global MINLP Solver
  • Format : Online Talk on Zoom
  • Author(s) :
    • Timo Berthold (Fair Isaac Germany GmbH)
  • Abstract : We will present the latest algorithmic advances and new features of the FICO Xpress Solver family. Next to enhanced MIP performance, a focus will be on recent new technologies like the ability to solve multi-objective optimization problems and mixed-integer nonlinear optimization problems to proven global optimality.

MS [02440] Advances in Optimization I

room : A502

• [04092] Maximum-Entropy Sampling: Algorithms and Application
  • Format : Talk at Waseda University
  • Author(s) :
    • Jon Lee (University of Michigan)
    • Marcia Fampa (Federal University of Rio de Janeiro)
  • Abstract : The maximum-entropy sampling problem (MESP) is to select a subset, of given size s, from a set of correlated Gaussian random variables, so as to maximize the differential entropy. MESP sits at the intersection of optimization, data science and information theory, and so it has attracted a lot of recent attention. We will give a broad overview of algorithmic work, concentrating on the many useful techniques related to various convex relaxations.
• [03117] A role of semidefinite relaxation in mathematics of phase retrieval
  • Format : Talk at Waseda University
  • Author(s) :
    • Ryoko Oishi-Tomiyasu (Kyushu University)
  • Abstract : In phase retrieval, a signal x is recovered from the amplitude |Ax| for a fixed linear operation A such as the Fourier transform. In crystallography, $x$ is a sum of finitely many Gaussian-like functions that represents the periodic discrete structure of atoms. We introduce that semidefinite relaxation works to determine the uniqueness of solutions and gain all the global solutions in this type of problem, mentioning an application found in a joint work with scientists.
• [03176] Exact Convergence Rate of Alternating Projections
  • Format : Talk at Waseda University
  • Author(s) :
    • Yoshiyuki Sekiguchi (Tokyo University of Marine Science and Technology)
    • Hiroyuki Ochiai (Kyushu University)
    • Hayato Waki (Kyushu University)
  • Abstract : We investigate the exact convergence rate of alternating projections for the nontransversal intersection of $S^n_+$ and an affine space. When the affine space is a line, we analyze the Newton polygon associated with the characteristic polynomial of the parametrizing matrix of the line and show that the convergence rate can be estimated by comparing ranks of submatrices of the basis matrix. We also investigate alternating projections for $S^3_+$ and a three dimensional affine space.
• [05522] Bridging Distributional and Risk-sensitive Reinforcement Learning with Provable Regret Bounds
  • Format : Talk at Waseda University
  • Author(s) :
    • Zhiquan Luo
    • Zhi-Quan Luo (The Chinese University of Hong Kong, Shenzhen)
  • Abstract : Risk-sensitive decision-making is vital in high-stakes fields like finance and medicine. Risk-sensitive reinforcement learning maximizes a risk measure instead of expected return. The exponential risk measure is widely used but involves complex algorithms and regret analysis. We propose a novel distributional reinforcement learning (DRL) algorithm for RSRL with a regret guarantee. Our approach utilizes risk-sensitive distributional dynamic programming and provides a regret upper bound via distributional optimism, while fixing and tightening the minimax lower bound.

contributed talk: CT173

room : A508

[02674] General Equilibrium with Unhedgeable Fundamentals and Heterogeneous Agents

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A508
• Type : Contributed Talk
• Abstract : We solve a general equilibrium model in which aggregate consumption has uninsurable growth shocks, rendering the market dynamically incomplete. Agents' stochastic discount factors depend on the history of unhedgeable shocks, agents trade assets dynamically, and the dispersion of agents' preferences impacts both the interest rate and asset prices, hence no representative agent exists.
• Classification : 91B50
• Format : Talk at Waseda University
• Author(s) :
  • Marko Hans Weber (National University of Singapore)
  • Paolo Guasoni (Dublin City University)

[02683] When to Sell an Asset? – A Distribution Builder Approach

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A508
• Type : Contributed Talk
• Abstract : We revisit the question of the optimal time of an asset sale from the point of view of Sharpe’s “Distribution Builder” approach: Instead of assuming the investor’s risk preferences in form of a utility function, the investor provides themself a distribution that should be attained when selling the asset at a stopping time (specified a priori). This obviously begs the question of which distributions are attainable for an investor. We connect this problem to the Skorokhod embedding problem for one-dimensional diffusions and provide explicit representation for optimal stopping times as well as their expected values. In the case that the target distribution is specified from a parametrized family (e.g., log-normal distributions), we show that optimality involves a mean-variance trade-off similar to the efficient frontier in Markowitz’s approach to portfolio optimization. This is joint work with Peter Carr.
• Classification : 91B70, 60G40
• Format : Talk at Waseda University
• Author(s) :
  • Stephan Sturm (Worcester Polytechnic Institute)

[01207] Optimal analysis of ecological-economic model with fishing tax and tourist entry-fee

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A508
• Type : Industrial Contributed Talk
• Abstract : A market-based fishing strategy in a multi-species fishery with a fair taxation policy may provide long-term sustainable growth. Fishery-based ecotourism with an entry fee for the tourist may further contribute to the financial improvement of the local people. Here we have proposed and analyzed a harvesting model that integrates fishery and fishery-based ecotourism with the open market economy theory. We determine the optimal fishing tax and entry fee that maximizes the social benefit.
• Classification : 91B76, 92B05, 91B55, 92D25, 92D40
• Author(s) :
  • Nandadulal Bairagi (Jadavpur University)
  • Santaanu Bhattacharya (Jadavpur University)

contributed talk: CT175

room : A510

[00818] BENCHMARKED ASSET MANAGEMENT WITH FIXED INCOME SECURITIES

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A510
• Type : Contributed Talk
• Abstract : We discuss a continuous-time portfolio optimization problem to beat a stochastic benchmark. In addition to plain equities, the proposed model is suitable to include fixed-income securities. In the proposed economy, the dynamics of assets and economic factors are described by non-linear stochastic differential equations, which make the model vast to account for various interest rate models. We prove the existence and uniqueness of optimal investment strategies for finite and infinite planning horizons.
• Classification : 91G10, 91G30, 91G15, 60G65, 35Q93
• Format : Talk at Waseda University
• Author(s) :
  • Mayank Goel (Birla Institute of Technology and Science Pilani)
  • Ravi Shankar (Birla Institute of Technology and Science Pilani)

[00376] Adaptive Optimal Market-Making Strategies with Inventory Liquidation Costs

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A510
• Type : Contributed Talk
• Abstract : An optimal market-making strategy for a high-frequency market maker under a discrete-time Limit Order Book model is presented. Interestingly, the optimal market-making strategy adapts to the past arrivals of market orders, making it adapted to previous market information. Admissibility and optimality of the optimal strategy are also proved. Finally, we test our assumptions empirically and compare the optimal strategy to one used under a non-adaptive framework where only the “average” past information is considered.
• Classification : 91G15, 93E20, 91B70, 91G30, 49J55
• Format : Talk at Waseda University
• Author(s) :
  • Jonathan Allan Chávez Casillas (University of Rhode Island)
  • José Enrique Figueroa López (Washington University in St. Louis)
  • Chuyi Yu (Washington University in St. Louis)
  • Yi Zhang (University of Illinois Urbana-Champaign)

[00998] An Optimal Consumption-Portfolio Strategy and Housing Choice Problem with a Loan-to-Value Ratio

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A510
• Type : Contributed Talk
• Abstract : This paper promotes a housing choice problem with a loan-to-value ratio by an extended dynamic programming approach. Before purchasing a house, an individual agent rents a house to live in. After purchasing a house, the agent owns a house and uses it as collateral for borrowing. One main contribution is that the loan-to-value ratio has positive effects on an individual agent's decisions both before and after the time of purchasing a house. We find that an individual agent with a higher loan-to-value ratio delays the time to buy a house and purchases a larger house. We provide closed-form solutions for each optimal policy. We also demonstrate the solutions numerically and discuss the economic implications.
• Classification : 91G10
• Format : Talk at Waseda University
• Author(s) :
  • Qi Li (Pusan National University)
  • Seryoong Ahn (Pukyong National University)
  • Ji-Hun Yoon (Pusan National University)

[02332] Risk Parity Portfolio in the COVID-19 Era: Indonesia Empirical Evidence

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A510
• Type : Contributed Talk
• Abstract : A Risk Parity Portfolio allocates capital thus each asset contributes the same amount of risk to the entire portfolio. In this paper, we conduct an empirical study of Risk Parity Portfolio with Gaussian Multivariate Mixture-Based Clustering based on financial ratio data. The daily closing price data of LQ45 index stocks listed on the Indonesia Stock Exchange were employed. The performance of the Risk Parity Portfolio outperformed the Tangency Portfolio in the COVID-19 era.
• Classification : 91G10, 91G80
• Format : Online Talk on Zoom
• Author(s) :
  • Rosita Kusumawati (Mathematics Department, Mathematics and Natural Sciences Faculty, Universitas Gadjah Mada)
  • Dedi Rosadi (Mathematics Department, Mathematics and Natural Sciences Faculty, Universitas Gadjah Mada)
  • Abdurakhman Abdurakhman (Mathematics Department, Mathematics and Natural Sciences Faculty, Universitas Gadjah Mada)

[02345] Performance of the Treynor Ratio in Compilation of Fuzzy Portfolios

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A510
• Type : Industrial Contributed Talk
• Abstract : In investing, investors have several characteristics, namely risk averse, risk seeker, and risk indifferent. Differences in these characteristics lead to the preparation of an optimal portfolio in decision-making. This study analyzes the application of the Treynor ratio as an instrument to measure portfolio performance. Portfolio preparation uses a fuzzy approach. The process of optimizing the model by applying multiobjective. The results of this study are the portfolio Treynor index ratio formed against the characteristics for the three characteristics of investors. This is used for investor recommendations in determining investment decisions.
• Classification : 91G10, 91G80
• Format : Online Talk on Zoom
• Author(s) :
  • Padrul Jana (Universitas Gadjah Mada)
  • Dedi Rosadi (Universitas Gadjah Mada)
  • Epha Diana Supandi (Universitas Islam Negeri Sunan Kalijaga)

contributed talk: CT179

room : A511

[00463] A kinetic model of crowd evacuation dynamics coupled with infectious disease contagion

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A511
• Type : Contributed Talk
• Abstract : We propose a kinetic theory model coupling crowd evacuation and disease spreading. Movement of individuals is modeled by a description of interactions among individuals. Interactions among healthy and infectious individuals may generate disease spreading if exposure time is long enough. Immunization of the population and awareness to contagion is also considered. The model is qualitatively studied and different scenarios related to gathering formation within indoor venues under the spread of an infectious disease are explored.
• Classification : 92-10, 92C60, 92D30
• Format : Talk at Waseda University
• Author(s) :
  • Juan Pablo Agnelli (CIEM CONICET & FaMAF Universidad Nacional de Córdoba)
  • Bruno Buffa (FaMAF Universidad Nacional de Córdoba)
  • Damian Alejandro Knopoff (CONICET, Argentina & Intelligent Biodata SL, Spain)
  • German Torres (IMIT CONICET & FaCENA UNNE)

[00620] Development of an ion channel model-framework

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A511
• Type : Contributed Talk
• Abstract : Ion channels in cell membranes are of ultimate importance in physiology. They control a large fraction of biological processes and are mainly investigated by current-voltage experiments. To support the interpretation of measured results, we develop a model-framework based on non-equilibrium thermodynamics that accounts for various important aspects, e.g., finite-volume effects and the surface charges of the channel. Julia-based numerical simulations are performed to compute current-voltage relations, with varying ion concentrations, applied voltages, and channel properties.
• Classification : 92-10, 92C40, 92-08
• Format : Talk at Waseda University
• Author(s) :
  • Christine Keller (Weierstrass Institute for Applied Analysis and Stochastics (WIAS))
  • Juergen Fuhrmann (Weierstrass Institute for Applied Analysis and Stochastics (WIAS))
  • Manuel Landstorfer (Weierstrass Institute for Applied Analysis and Stochastics (WIAS))
  • Barbara Wagner (Weierstrass Institute for Applied Analysis and Stochastics (WIAS))

[00677] Mathematical Epidemiology as a decision tool

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A511
• Type : Industrial Contributed Talk
• Abstract : Mathematics is a powerful tool for tackling real world problems; concretely, we are interested in monitoring epidemics. Some members of the MOMAT Research Group -Complutense University of Madrid- have worked in collaboration with veterinary groups, healthcare companies and public entities of the Spanish healthcare system. In this talk, we present some mathematical models developed by this research group for both animal -e.g., Classical Swine Fever, Bluetongue- and human -e.g., COVID-19, Ebola- infectious diseases.
• Classification : 92-10, 92Dxx, Mathematical Epidemiology
• Format : Talk at Waseda University
• Author(s) :
  • Alicja B. Kubik (Universidad Complutense de Madrid)
  • Benjamin Ivorra (Universidad Complutense de Madrid)
  • Angel M. Ramos (Universidad Complutense de Madrid)
  • María Vela-Pérez (Universidad Complutense de Madrid)
  • Miriam R. Ferrández (Instituto de Matemática Interdisciplinar)

[00438] Network stability in co-evolved spatially-explicit model ecological communities

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A511
• Type : Contributed Talk
• Abstract : The self-assembly of ecological communities on complex spatial networks from an initial species can be mathematically modelled by a combination of ecological and evolutionary processes. We investigate how the topology of the spatial network influences the structure of the co-evolved populations, and hence the stability of the resulting meta-community of species against perturbations including invasion, extinction, patch removal, and alterations to the spatial environment. In response, different nature reserve configurations can simulate biodiversity conservation strategies.
• Classification : 92-10, 37N25
• Format : Online Talk on Zoom
• Author(s) :
  • Gavin Michael Abernethy (University of Stirling)

[00745] Fluid flow and nutrient transport in hollow fibre membrane bioreactors

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A511
• Type : Contributed Talk
• Abstract : We present an axisymmetric model of fluid flow through a hollow fibre membrane bioreactor for applications in tissue engineering. We derive a reduced model by exploiting the small aspect ratio of bioreactor radius to length. Coupled to a system of reduced-order advection-reaction-diffusion equations for nutrient transport, we reveal how nutrient delivery to cells depends on membrane permeability. We then determine how spatial variations in scaffold permeability can be established to tune nutrient delivery to cells.
• Classification : 92-10, 92C35, 76Z05, 92C50, 76D08, Tissue Engineering
• Format : Online Talk on Zoom
• Author(s) :
  • George Booth (University of Oxford)
  • Mohit Dalwadi (University College London)
  • Cathy Ye (University of Oxford)
  • Pierre-Alexis Mouthuy (University of Oxford)
  • Sarah Waters (University of Oxford)

MS [00924] Calibration and Validation of Mathematical Models for Biological Systems

room : A512

• [01710] Multiscale spatiotemporal reconstruction of single-cell genomics data
  • Format : Talk at Waseda University
  • Author(s) :
    • Qing Nie (University of California, Irvine)
  • Abstract : Cells make fate decisions in response to dynamic environments, and multicellular structures emerge from multiscale interplays among cells and genes in space and time. The recent single-cell genomics technology provides an unprecedented opportunity to profile cells. However, those measurements are taken as static snapshots of many individual cells that often lose spatial information. How to obtain temporal relationships among cells from such measurements? How to recover spatial interactions among cells, such as cell-cell communication? In this talk I will present our newly developed computational tools that dissect transition properties of cells and infer cell-cell communication based on nonspatial single-cell genomics data. In addition, I will present methods to derive multicellular spatiotemporal pattern from spatial transcriptomics datasets. Through applications of those methods to systems in development and regeneration, we show the discovery power of such methods and identify areas for further development for spatiotemporal reconstruction of single-cell genomics data.
• [01731] Integrating quantitative MRI with computational modeling to predict the response of breast cancers to neoadjuvant therapy
  • Format : Online Talk on Zoom
  • Author(s) :
    • Thomas Yankeelov (The University of Texas at Austin)
    • Chase Christenson (The University of Texas at Austin)
    • Casey Stowers (The University of Texas at Austin)
    • Reshmi Patel (The University of Texas at Austin)
    • Chengyue Wu (The University of Texas at Austin)
  • Abstract : We will discuss how magnetic resonance imaging data (MRI) can initialize and constrain mathematical models describing cancer proliferation, migration/invasion, vascular status, and drug-related growth inhibition and cell death. More specifically, we will focus on 1) incorporating patient-specific MRI data into biology-based mathematical models, and 2) optimizing outcomes via patient-specific digital twins in breast cancer. The long-term goal is to provide a rigorous methodology that allows for optimizing therapeutic interventions on a patient-specific basis.
• [04716] Deep Hybrid Modeling of Neuronal Dynamics using Generative Adversarial Networks
  • Format : Online Talk on Zoom
  • Author(s) :
    • Casey Diekman (New Jersey Institute of Technology)
    • Soheil Saghafi (New Jersey Institute of Technology)
  • Abstract : Mechanistic modeling and machine learning methods are powerful techniques for approximating biological systems and making accurate predictions from data. However, when used in isolation these approaches suffer from distinct shortcomings: model and parameter uncertainty limit mechanistic modeling, whereas machine learning methods disregard the underlying biophysical mechanisms. To address these shortcomings, we build Deep Hybrid Models (DeepHMs) that combine deep learning with mechanistic modeling to identify the distributions of mechanistic modeling parameters coherent to the data. We employed DeepHM to identify which ionic conductances are responsible for the altered excitability properties of CA1 pyramidal neurons in mouse models of Alzheimer’s disease.
• [03082] Gene regulatory network dynamics in single cells
  • Format : Online Talk on Zoom
  • Author(s) :
    • Adam L MacLean (University of Southern California)
    • Megan Rommelfanger (University of Southern California)
  • Abstract : Single-cell genomics offer unprecedented resolution with which to study cell fate decision-making. We present new tools to infer gene regulatory networks (GRNs) controling cell fate decisions and model their multiscale dynamics. We introduce popInfer, single-cell multi-modal GRN inference via regularized regression, and demonstrate its potential for network discovery. We develop a single-cell resolved multiscale model coupling cell-cell communication with gene regulatory network dynamics, with which we discover a profound role for cell-cell communication in hematopoiesis.

contributed talk: CT180

room : A601

[00300] Coupling macro-micro simulations in complex fluids

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A601
• Type : Contributed Talk
• Abstract : Some of the most remarkable properties and functions served by some complex fluids originate from the interplay between external fields and microstructural dynamics. From a computational point of view this generates a set of challenges related to the need of coupling dynamics at different length and times scales, sometimes spanning several orders of magnitude. Micro-macro simulations have gained a lot of recognition within the field because these methods allow capturing full dynamics at the macroscale without losing resolution at the microscale. In this talk, we will review our efforts to couple existing macroscopic solvers for the Navier-Stokes equations with microstructural dynamics described by Langevin-type equations. In particular, we will discuss dumbbells models -under viscometric and capillary thinning flows fields- and parallel computing using GPUs.
• Classification : 92B05, 76A05, 76A10, 76D05, 97M60
• Format : Talk at Waseda University
• Author(s) :
  • Paula A Vasquez (University of South Carolina)
  • Michael Cromer (RIT)

[00035] Effects of toxicity and zooplankton selectivity under seasonal pattern of viruses on plankton dynamics

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A601
• Type : Contributed Talk
• Abstract : A mathematical model for the interacting dynamics of phytoplankton-zooplankton is proposed. The phytoplankton have ability to take refuge and release toxins to avoid over predation by zooplankton. The zooplankton are provided some additional food to persist in the system. The phytoplankton are assumed to be affected directly by an external toxic substance whereas zooplankton are affected indirectly by feeding on the affected phytoplankton. We incorporate seasonal variations in the model, assuming the level of nutrients, refuge and the rate of toxins released by phytoplankton as functions of time. Our results show that when high toxicity and refuge cause extinction of zooplankton, providing additional food supports the survival of zooplankton population and controls the phytoplankton population. Prey refuge and additional food have stabilizing effects on the system; higher values of the former results in extinction of zooplankton whereas phytoplankton disappear for larger values of the latter. Seasonality in nutrients level and toxins released by phytoplankton generates higher periodic solutions while time-dependent refuge of phytoplankton causes the occurrence of a period-three solution. The possibility of finding additional food for zooplankton may push back the ecosystem to a simple stable state from a complex dynamics.
• Classification : 92B05, 92D25, 92D30, 37A50, 34D05
• Format : Online Talk on Zoom
• Author(s) :
  • Samares Pal (University of Kalyani)

[00375] Modelling Typhoid Fever Transmission: Optimal control and Cost-Effectiveness Analysis

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A601
• Type : Industrial Contributed Talk
• Abstract : Typhoid fever has been a public health challenge globally, most especially in the developing countries where sanitation and personal hygiene are not taken serious coupled with non-availability of safe-drinking water. In this paper, a deterministic mathematical model of direct and indirect mode of transmission of Typhoid fever dynamics is formulated to investigate the influence of limited clinical efficacy of antibiotics administer to patients suffering from the disease with optimal control and cost-effectiveness analysis. Typhoid fever has been a public health challenge globally, most especially in the developing countries where sanitation and personal hygiene are not taken serious coupled with non-availability of safe-drinking water. In this paper, a deterministic mathematical model of direct and indirect mode of transmission of Typhoid fever dynamics is formulated to investigate the influence of clinical efficacy of antibiotics administer to patients suffering from the disease. The basic reproduction number is analytically computed, and existence and local stability condition of disease-free equilibrium is investigated. Subsequently, the global sensitivity analysis of the model parameters is computed. The optimal control and cost-effectiveness analysis were also computed. Our results suggest that hygiene practice and awareness campaign, and disinfection or sterilization or bacteria decay control is the most cost-effective in eliminating the disease from the population and from preventing the susceptible individuals from contracting the bacteria disease.
• Classification : 92BXX, 92-XX, 92-10, 91-XX, 91-10, Mathematical modeling of infectious disease(Biomathematics)
• Author(s) :
  • kazeem Austin TIJANI (Federal University of Agriculture(J. S Tarka university), Makurdi)
  • Chinwendu Emilian MADUBUEZE (Federal university of Agriculture Makurdi Nigeria )
  • Iortyer Reuben GWERYINA (Federal university of Agriculture(J.S. Tarka University), Makurdi))

[00892] Predicting response to pediatric leukemia with flow cytometry data

• Session Time & Room : 3C (Aug.23, 13:20-15:00) @A601
• Type : Contributed Talk
• Abstract : 15% of children with B-cell acute lymphoblastic leukemia fail to achieve response or long-term remission. With new treatments being developed to provide an alternative for this subset of patients, an improved risk classification at diagnosis can help to plan and prepare for this eventuality. Flow cytometry is currently used to characterize the leukemic clone but it has no prognosis value. In this work we use flow cytometry data at diagnosis from 250 pediatric patients from hospitals in Spain to find features associated with response by means of an array of computational methods.
• Classification : 92Bxx
• Author(s) :
  • Alvaro Martínez-Rubio (University of Cadiz)
  • Salvador Chulián (University of Cádiz)
  • Ana Niño-López (Department of Mathematics, Universidad de Cádiz)
  • Víctor Manuel Pérez-García (University of Castilla-La Mancha)
  • María Rosa (University of Cadiz)

MS [00420] Painlevé equations, Applications, and Related Topics

room : A617

• [03574] A dynamical systems approach to map enumeration
  • Format : Online Talk on Zoom
  • Author(s) :
    • Joceline Lega (University of Arizona)
  • Abstract : Freud orbits are trajectories of discrete Painlevé equations that describe the evolution of recurrence coefficients for orthogonal polynomials. We will introduce a nonlinear transformation, which converts a Freud orbit into a solution that converges towards a fixed point along a center manifold. Subsequent analysis will lead to an asymptotic expansion whose terms are generating functions for map enumeration. Examples of map counts will be provided. This is joint work with Nick Ercolani and Brandon Tippings.
• [03010] An affine Weyl group action on the basic hypergeometric series
  • Format : Talk at Waseda University
  • Author(s) :
    • Takao Suzuki (Kindai University)
  • Abstract : Recently, we formulated a higher order generalization of the $q$-difference Painlevé equations called the $q$-Garnier system in a framework of an extended affine Weyl group of type $A^{(1)}_{2n+1}\times A^{(1)}_1\times A^{(1)}_1$. On the other hand, the $q$-Garnier system admits a particular solution in terms of the basic hypergeometric series ${}_{n+1}\phi_n$. In this talk, we investigate an action of the extended affine Weyl group on ${}_{n+1}\phi_n$.
• [03311] On the growth properties of some families of birational maps
  • Format : Online Talk on Zoom
  • Author(s) :
    • Giorgio Gubbiotti (Universita degli Studi di Milano)
    • Michele Graffeo (Politecnico di Milano)
  • Abstract : We characterise the growth and integrability properties of a family of elements in the Cremona group of a complex projective space in dimension three using techniques from algebraic geometry. This collection consists of maps obtained by composing the standard Cremona transformation $\mathrm{c}_3\in\mathrm{Bir}(\mathbb{P}^3)$ with projectivities permuting the fixed points of $\mathrm{c}_3$ and the points over which $\mathrm{c}_3$ performs a divisorial contraction. Time permitting, we discuss the possible extensions of this construction to higher dimensions.
• [05042] Laguerre (q-Laguerre) Weight Recurrence and Geometric Theory of Painlevé equations
  • Format : Online Talk on Zoom
  • Author(s) :
    • Jie Hu (Jinzhong University（晋中学院）)
  • Abstract : The Sakai geometric theory of Painlevé equations is useful for identify difference or differential equations as corresponding Painlevé equations. In this talk we consider two examples of recurrence relations appearing in study of recurrence coefficients of semi-classical orthogonal polynomials, namely, polynomials with Laguerre weight and with the deformed q-Laguerre weight. Using the geometry, we give explicit change of variables matching these equations with some standard discrete Painlevé equations.

MS [00523] Implicit methods for hyperbolic problems and their extensions and applications

room : A618

• [04131] Semi-implicit schemes for a convection-diffusion-reaction model of sequencing batch reactors
  • Format : Talk at Waseda University
  • Author(s) :
    • Raimund Bürger (Universidad de Concepción)
    • Julio Careaga (Radboud University)
    • Stefan Diehl (Lund University)
    • Romel Pineda (Universidad de Concepción)
  • Abstract : Sequencing batch reactors are used in wastewater treatment for the settling of solid biomass particles simultaneously with biochemical reactions with nutrients dissolved in the liquid. This unit can be modeled as a moving-boundary problem for a degenerating convection-diffusion-reaction system. This model is transformed to a fixed computational domain and is discretized by an explicit and semi-implicit monotone schemes. Both variants obey an invariant region property. Numerical examples illustrate that the semi-implicit variant is more efficient.
• [01691] High resolution well-balanced compact implicit numerical scheme for numerical solution of the shallow water equations
  • Format : Talk at Waseda University
  • Author(s) :
    • Michal Žeravý (Slovak University of Technology in Bratislava)
    • Peter Frolkovič (Slovak University of Technology in Bratislava)
  • Abstract : In this talk, we deal with the numerical solution of shallow water equations with topography in one-dimensional case using a high resolution well-balanced compact implicit numerical scheme. The upwind scheme uses the fractional step method with the fast sweeping method. Consequently, the Jacobian matrix of the discrete system of nonlinear algebraic equations is always either a lower or upper triangular matrix.
• [01692] Numerical solution of scalar hyperbolic problems using the third order accurate compact implicit scheme
  • Format : Talk at Waseda University
  • Author(s) :
    • Dagmar Zakova (Slovak University of Technology in Bratislava)
    • Peter Frolkovic (Slovak University of Technology in Bratislava)
  • Abstract : This work presents compact implicit numerical schemes for solving scalar hyperbolic problems. We propose details of the third-order accurate scheme using the finite volume method. To avoid unphysical oscillations in the case of nonsmooth solution, we modify the scheme using ENO and WENO approximation in space. Applications to one-dimensional conservation laws are shown.
• [05425] High-fidelity multiderivative time integration for compressible flows
  • Format : Talk at Waseda University
  • Author(s) :
    • Arjun Thenery Manikantan (Hasselt University)
    • Jochen Schütz (Hasselt University)
    • Jonas Zeifang (Hasselt University)
  • Abstract : We present a high-order parallel-in-time implicit multiderivative time-stepping scheme for Navier Stokes equations spatially discretized with the Discontinuous Galerkin Spectral element method. The time-stepping starts with a predicted solution, and the correction steps increase the order of accuracy up to the order of the underlying quadrature rule. Implicit non-linear(linear) equations are solved using Newton's and the general minimal residual methods. Extensive numerical results are shown for convergence, parallel efficiency, and other scheme features.