MS and CT list / Aug. 23, 17:40-19:20.

MS [02406] European Research Council (ERC) information session

room : G301

• [03125] European Research Council (ERC): insight into funding opportunities
  • Format : Talk at Waseda University
  • Author(s) :
    • Joan Vazquez Molina (European Research Council Executive Agency)
  • Abstract : The ERC's mission is to encourage the highest quality research in Europe through competitive funding and to support investigator-driven frontier research across all fields, based on scientific excellence. I will give an overview of our funding opportunities, which are open to researchers from any nationality and at any career stage. I will provide insight into our evaluation and selection process, focusing on details of particular interest for the industrial and applied mathematics community.
• [05538] Building a new mathematical adventure with ERC support.
  • Author(s) :
    • Alfio Quarteroni (Politecnico di Milano)
  • Abstract : The generous ERC support has enabled me to lay the scientific foundations for computational medicine, an immensely captivating field that presents extraordinary mathematical challenges while offering the opportunity to contribute to solving complex problems of clinical and societal significance. In this presentation, I will outline the key milestones of this journey, and briefly touch upon my decade-long experience as the chairman of the ERC Mathematical Panel for Consolidator Grants.
• [05548] Extreme-scale Mathematically-based Computational Chemistry Synergy project
  • Author(s) :
    • Laura Grigori (EPFL and PSI)
  • Abstract : In this talk we will describe the ERC Synergy project entitled Extreme-scale Mathematically-based Computational Chemistry. Molecular simulation is one of the most dynamic areas of scientific computing. Its field of application is very broad, ranging from theoretical chemistry and drug design to materials science and nanotechnology. We will review in this talk some of the research topics, challenges and achievements of this multidisciplinary effort that was made possible by ERC-Synergy-type funding.
• [05567] A dedicated Project Development Office for Mathematics
  • Author(s) :
    • Wil Schilders (Eindhoven University of Technology)
  • Abstract : At Eindhoven University, end of 2013 we started a Project Development Office (PDO) within the Department of Mathematics and Computer Science. This office has all the knowledge and expertise to inform mathematicians about suitable project opportunities, disregarding less suitable options, and helps actively with the writing of proposals. Personal grants like ERC proposals are of prime importance, PDO has a database of successful proposals. It has turned out to be a very successful move, other university departments and universities are copying the concept.

contributed talk: CT009

room : G304

[00922] Matrix Factorization for Change Detection in HyperSpectral Images

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G304
• Type : Contributed Talk
• Abstract : When hyperspectral images are analyzed, a big amount of data needs to be processed and therefore, specific matrix factorization algorithms are used to express the original problem in suitable subspacesWe show some recent results derived also by using spatial and spectral functions to compute a lower rank approximation of the original matrix and to measure the reconstruction error between the input image and the approximate one, with applications to the task of change-detection.
• Classification : 15A23
• Format : Talk at Waseda University
• Author(s) :
  • Antonella Falini (Università degli studi di Bari Aldo Moro)
  • Francesca Mazzia (Università degli studi di Bari Aldo Moro, Italy)

[00546] Recent advances on the conjugate discrete-time algebraic Riccati equation.

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G304
• Type : Contributed Talk
• Abstract : In this talk, we consider a class of conjugate discrete-time Riccati equations, arising originally from the linear quadratic regulation problem for discrete-time antilinear systems. A constructive proof is given for the existence of the maximal solution. Furthermore, an accelerated fixed-point iteration based on the semigroup property is developed for computing the maximal solution and the convergences is at least R-superlinear. An example is given to demonstrate the correctness of our main theorem.
• Classification : 15A24, 65H05, 93A99
• Format : Talk at Waseda University
• Author(s) :
  • Chun-Yueh Chiang (Center for General Education, National Formosa University)
  • Hung-Yuan Fan (National Taiwan Normal University)

[01097] Versal deformations as a tool of matrix analysis

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G304
• Type : Contributed Talk
• Abstract : Reductions of matrices or matrix pencils to canonical forms are unstable operations: both the corresponding canonical forms and the reduction transformations depend discontinuously on the entries of an original matrix or pencil. This issue complicates the use of canonical forms for numerical purposes. Therefore V.I. Arnold introduced a notion of versal deformations. We will discuss versal deformations and their use in codimension computations, investigation of possible changes in eigenstructures, and reduction to structured perturbations.
• Classification : 15A63, 15A21
• Format : Talk at Waseda University
• Author(s) :
  • Andrii Dmytryshyn (Örebro University)
  • Andrii Dmytryshyn (Örebro University)

[00206] Tensor product-type methods for solving Sylvester tensor equations

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G304
• Type : Contributed Talk
• Abstract : The tensor biconjugate gradient $($TBiCG$)$ method has recently been proposed for solving Sylvester tensor equations. TBiCG is based on BiCG that may exhibit irregular convergence behavior. To overcome the limitations of BiCG, product-type methods have been proposed. In this study, we propose tensor product-type methods to solve Sylvester tensor equations. Furthermore, we consider the preconditioned versions using the NKP preconditioner. Numerical experiments illustrate that the proposed methods are competitive with some existing methods.
• Classification : 15A69, 65F10
• Format : Talk at Waseda University
• Author(s) :
  • Jing Niu (Nagoya University)
  • Tomohiro Sogabe (Nagoya University)
  • Lei Du (Dalian University of Technology)
  • Tomoya Kemmochi (Nagoya University)
  • Shao-Liang Zhang (Nagoya University)

[02254] Optimized first order alternating algorithms for fast and accurate low rank tensor decomposition

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G304
• Type : Contributed Talk
• Abstract : CP tensor decomposition has been proven to be a powerful tool for extracting information from large high order tensor, being widely applied in many areas such as chemistry, biology and medical science. However, efficiently computing the CP tensor still remains a challenge. In this study, we propose some optimized first order alternating least square algorithms for low rank tensor decomposition. We validate and illustrate the proposed algorithms by using simulated and real multi-way data.
• Classification : 15A72, 15A69, 65Z05
• Format : Talk at Waseda University
• Author(s) :
  • HUIWEN YU (Aarhus University)
  • Ove Christiansen (Aarhus University)

contributed talk: CT011

room : G305

[00014] Pathway Fractional Integral Operator with Composition of Generalized function G_(ρ,η,r) [a, z]

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G305
• Type : Contributed Talk
• Abstract : The purpose of this paper is to consider the properties of generalized function G_$(ρ,η,r)$ $[a, z]$. For this purpose we obtain certain image formulas using Pathway fractional integral operators with these properties. We also mentioned some important special cases of the main results.
• Classification : 26A33, 33E12
• Format : Talk at Waseda University
• Author(s) :
  • Harish Nagar (Chandigarh University)
  • Seema Kabra (Sangam University)

[00846] ESR fractional model with non-zero uniform average blood velocity

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G305
• Type : Contributed Talk
• Abstract : This article discusses a new solution to the time-fractional ESR model, taking into account the non-zero average blood velocity. We not only obtain an analytic solution to the generalized model of Sharma et al. and da Sousa et al., but also we present some new results which establish that the developed fractional order model is better-suited one by using which predicting the ESR rate can take place more accurately.
• Classification : 26A06, 26A33, 33E12, 35R11
• Format : Online Talk on Zoom
• Author(s) :
  • Abhijit Shit (Indian Institute of Technology Guwahati)
  • Swaroop Nandan Bora (Indian Institute of Technology Guwahati)

[00173] Symmetries and Explicit Solutions of Fractional Nonlinear Drinfeld–Sokolov–Satsuma–Hirota System

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G305
• Type : Contributed Talk
• Abstract : In this work, a space-time fractional nonlinear Drinfeld–Sokolov–Satsuma–Hirota system is considered. The symmetry approach and power series expansion technique are applied to derive the explicit solutions of the system. The coupled DSSH system was seen as a special form example of Lax pairs and a special case of the four-reduced Kadomtsev–Petviashvili hierarchy in literature. The main motivation for present work is the global behaviour and various applications of fractional DSSH in applied science. The results obtained in the paper can be useful in calculating in conservation laws of the system.
• Classification : 26A33, 76M60, Fractional Derivatives, Symmetry Analysis
• Format : Online Talk on Zoom
• Author(s) :
  • Komal Singla (Chandigarh University)

[00200] Montgomery identity and Ostrowski type inequalities via Katugampola integral operator

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G305
• Type : Contributed Talk
• Abstract : In this talk, we will discuss the extended version of Montgomery identity using Katugampola integral operators. Also we will establish Ostrowski type integral inequalities and fractional integral inequality for product of two functions.
• Classification : 26A33, 26D07, 26D10
• Format : Online Talk on Zoom
• Author(s) :
  • Henok Desalegn Desta (Addis Ababa university )
  • Deepak B. Pachpatte (Dr. Babasaheb Ambedkar Marathwada University, India)
  • Tadesse Abdi (Addis Ababa University)
  • Jebessa B. Mijena ( Georgia College & State University)

[00334] A generalized study of the distribution of buffer over calcium on a fractional dimension

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G305
• Type : Contributed Talk
• Abstract : Here, we focus on cellular calcium fluctuations with different buffers, including calcium-binding buffers, using the Hilfer fractional advection-diffusion equation for cellular calcium. By combining with intracellular free calcium ions, buffers reduce the cytosolic calcium concentration. Models are developed for association, dissociation, diffusion, and buffer concentration. In comparison to the conventional calcium model, the modified Hilfer calcium model offers a richer physical explanation. Numerical simulations are also carried out in MATLAB.
• Classification : 26A33, 35Q92, 44A10, 92C99
• Format : Online Talk on Zoom
• Author(s) :
  • Sanjay Bhatter (Malaviya National Institute of Technology Jaipur)
  • Kamlesh Jangid (Central University of Rajasthan, Ajmer)
  • Shyamsunder - (Malaviya National Institute of Technology Jaipur)
  • Sunil Dutt Purohit (Rajasthan Technical University, Kota)
  • Dumitru Baleanu (Cankaya University, Ankara)
  • Daya Lal Suthar (Wollo University)

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: CT022

room : G402

[00219] Approximation methods for solving pursuit-evasion differential game

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G402
• Type : Contributed Talk
• Abstract : In this study we present an appropriate singular, zero-sum, linear-quadratic differential game. One of the main features of this game is that the weight matrix of the minimizer’s control cost in the cost functional is singular. Due to this singularity, the game cannot be solved either by applying the Isaacs MinMax principle, or the Bellman–Isaacs equation approach. As an application, we introduced an pursuit-evasion differential game with an appropriate regularized cost functional and developed an appropriate dual representation. Developing the variational derivatives of this regularized cost functional, we apply several approximation methods and show how the numerical results coincide with the dual representation.
• Classification : 34H05, 49J15, 91A23, 90C90, 49N15
• Format : Talk at Waseda University
• Author(s) :
  • Oleg Kelis (Technion)
  • Oleg Kelis (The Technion—Israel Institute of Technology)

[00987] Role of applied mathematics on optimum MR damper location for LQG controlled framed structure

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G402
• Type : Industrial Contributed Talk
• Abstract : This work addresses a Linear Quadratic Gaussian Design (LQG) based semi-active control algorithm for vibration reduction of building structures. The controlled damper force required by the structure has been calculated from an MR damper. A building frame has been selected to illustrate the performance of the proposed algorithm. Four different earthquake acceleration data has been used as input vibration data to the numerical frame
• Classification : 34H10, 34H15, 34H20, 70H03, 70H20
• Format : Talk at Waseda University
• Author(s) :
  • MANIKANDAN RAJASEKARAN (DEPARTMENT OF APPLIED MATHEMATICS BHARATHIYAR UNIVERSITY COIMBATORE TAMIL NADU INDIA)
  • PAYEL CHAUDRI (IIT KHARAGPUR)
  • SAKTHIVEL R (PROFESSOR DEPARTMENT OF APPLIED MATHEMATICS BHARATHIYAR UNIVERSITY COIMBATORE TAMIL NADU INDIA)

[02907] Robust Train Trajectory Optimization

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G402
• Type : Contributed Talk
• Abstract : Variating operating conditions may produce delays in railways. We model the Robust Train Trajectory Optimization (RTTO) problem aiming to minimize the impact of model parameter uncertainty on the calculated energy-efficient trajectories, which would be drivable under any of the considered operating conditions. We analyze RTTO using the Robust Maximum Principle, reformulate the problem as a Quadratically-Constrained Quadratic Programming problem and showcase the performance of the model in a real case study.
• Classification : 34H05, 49K35, 93-08, 90C47, 90C25
• Format : Talk at Waseda University
• Author(s) :
  • Alex Cunillera (Delft University of Technology)
  • Ramon M. Lentink (Nederlandse Spoorwegen)
  • Niels van Oort (Delft University of Technology)
  • Rob M. P. Goverde (Delft University of Technology)

[00252] Stabilization and adaptive event-triggered tracking control for non-linear systems

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G402
• Type : Contributed Talk
• Abstract : An adaptive event-triggered-based output tracking problem for non-linear network control systems with malicious attacks is discussed in this work. An adaptive event-triggered mechanism is developed to reduce the number of triggering and communication burdens. Feedback control is constructed to force the output trajectories to track reference input with disturbance and malicious attacks. Tracking objective transformed into input-output finite time stabilization. Sufficient conditions are developed based on Lyapunov–Krasovskii functional and advanced integral inequalities.
• Classification : 34H05, 93D25, Systems and control theory
• Format : Online Talk on Zoom
• Author(s) :
  • Vijayakumar Muthusamy (Anna University )

MS [02600] Applied and computational discrete algorithms

room : G404

• [03099] On heuristics for the Birkhoff--von Neumann decomposition
  • Format : Online Talk on Zoom
  • Author(s) :
    • Bora Ucar (CNRS and ENS de Lyon)
    • Jeremy Cohen (CREATIS, CNRS)
  • Abstract : The Birkhoff--von Neumann decomposition expresses a doubly stochastic matrix as a convex combination of permutation matrices. This talk will be an introduction to this decomposition. We will discuss algorithmic and combinatorial problems associated with this decomposition.
• [03435] Recent Advances in Streaming (Hyper)Graph Partitioning
  • Format : Online Talk on Zoom
  • Author(s) :
    • Christian Schulz (Heidelberg University)
  • Abstract : Partitioning a (hyper)graph into balanced blocks such that few edges run between blocks is a key problem for large-scale distributed processing. Currently there is a gap observed in the space of available partitioning algorithms. On the one hand, there are streaming algorithms that have been adopted to partition massive graph data on small machines. In the streaming model, vertices arrive one at a time including their neighborhood and then have to be assigned directly to a block. These algorithms can partition huge graphs quickly with little memory, but they produce partitions with low solution quality. On the other hand, there are offline (shared-memory) multilevel algorithms that produce partitions with high quality but also need a machine with enough memory to partition huge networks. In this talk, we present recent advances in the area of streaming algorithms for the problem. First, we present a buffered streaming approach: this model allows to read more than one node and its neighborhood at the time. This enables our algorithm to leverage multilevel techniques, and thus significantly improve solution quality while surprisingly also enhancing the overall complexity of the algorithm. On the other hand, we present a shared-memory streaming multi-recursive partitioning scheme that performs recursive multi-sections on the fly without knowing the overall input graph to compute hierarchical partitionings. If the topology of a distributed system is known, it is possible to further optimize the communication costs by mapping partitions onto processing elements.
• [04746] Efficient Data Structures for Sparse Dynamic Graphs
  • Format : Talk at Waseda University
  • Author(s) :
    • Helen Xu (Lawrence Berkeley National Laboratory)
  • Abstract : Sparse graphs underlie many key applications such as social networks analyses and scientific computing. This talk discusses dynamic graph data structures and how to choose data structures that optimize for locality, which is key to performance in graph computations. The focus is on how different use cases, which can cause different data patterns and access patterns, can influence the design of these structures and how to exploit these differences to maximize performance.
• [04669] Communication Efficient Stratified SGD on Distributed-Memory Systems
  • Format : Online Talk on Zoom
  • Author(s) :
    • Nabil Abubaker (Bilkent University)
    • Ozan Karsavuran (Lawrence Berkeley National Lab)
    • Cevdet Aykanat (Bilkent University)
  • Abstract : Stratified Stochastic Gradient Descent (SSGD) enables stale-free low-rank approximation of sparse matrices on distributed-memory systems. We present a framework to efficiently scale SSGD on HPC systems. The framework leverages point-to-point communications to reduce the bandwidth overhead, and a novel combinatorial algorithm to reduce the upper bound on the number of messages from O(K^2) to O(K logK), where K is the number of processors. Our experiments show an order of magnitude performance gap in favor of our framework-enabled SSGD compared to the state-of-the-art.

MS [01768] Computer-assisted proofs in differential equations

room : G405

• [03720] Validated Numerics for divergent series via the Borel Transform
  • Format : Talk at Waseda University
  • Author(s) :
    • Jason Desmond Mireles James (Florida Atlantic University)
  • Abstract : Parabolic invariant manifolds are associated with fixed points of diffeomorphisms which have one as an eigenvalue of the linearization, or equilibrium solutions of differential equations which have zero as an eigenvalue. Supposing that the map or vector field is real analytic, It is well known (for example Baldoma and Haro, 2008) that while the Taylor expansion of the manifold may diverge, it typically does so in a Gevery fashion. That is, the power series coefficients diverge like a factorial. In this case, some truncations of the divergent series may still provide useful approximation, and it is desirable to have quantitative bounds on the errors. This is in fact necessary if the expansion is going to be used as an ingredient of a subsequent computer assisted proof. I will discuss a method for obtaining such bounds based on Borel resummation. The idea is that the Borel transform of the conjugacy equation describing the parabolic manifold has much nicer properties than the original equation. For example the transformed equation typically has analytic solutions. I will discuss methods for solving the transformed equation using validated numerics. If one can analytically continue this solution (in a process similar to numerical integration) to an open set covering the positive real axis in the complex Borel Plane, then it is possible to take a Laplace transform, recovering the solution to the original problem. This procedure also leads to validated computer assisted error bounds.
• [04398] Characterising blenders via covering relations and cone conditions
  • Format : Talk at Waseda University
  • Author(s) :
    • Hinke M Osinga (University of Auckland)
    • Bernd Krauskopf (University of Auckland)
    • Piotr Zgliczynski (Jagiellonian University)
    • Maciej Capinski (AGH University of Science and Technology)
  • Abstract : A blender is an invariant hyperbolic set of a diffeomorphism with the property that its stable or unstable manifold has a dimension larger than expected from the underlying hyperbolic splitting. We present a characterisation of a blender based on the correct topological alignment of sets in combination with the propagation of cones. It is applicable to multidimensional blenders in ambient phase spaces of any dimension. The required conditions can be verified by checking properties of a single iterate of the diffeomorphism, which is achieved by positioning the required sets in such a way that they form a suitable sequence of coverings. This setup is flexible and allows for a rigorous, interval arithmetic based, computer assisted validation.
• [03900] Validated integration of semilinear parabolic PDEs
  • Format : Talk at Waseda University
  • Author(s) :
    • Maxime Breden (Ecole polytechnique)
    • Jan Bouwe van den Berg (VU Amsterdam)
    • Ray Sheombarsing (VU Amsterdam)
  • Abstract : Integrating evolutionary partial differential equations (PDEs) is an essential ingredient for studying the dynamics of the solutions. Indeed, simulations are at the core of scientific computing, but their mathematical reliability is often difficult to quantify, especially when one is interested in the output of a given simulation, rather than in the asymptotic regime where the discretization parameter tends to zero. In this paper we present a computer-assisted proof methodology to perform rigorous time integration for scalar semilinear parabolic PDEs with periodic boundary conditions. We formulate an equivalent zero-finding problem based on a variations of constants formula in Fourier space. Using Chebyshev interpolation and domain decomposition, we then finish the proof with a Newton-Kantorovich type argument. The final output of this procedure is a proof of existence of an orbit, together with guaranteed error bounds between this orbit and a numerically computed approximation. We illustrate the versatility of the approach with results for the Fisher equation, the Swift-Hohenberg equation, the Ohta-Kawasaki equation and the Kuramoto–Sivashinsky equation. We expect that this rigorous integrator can form the basis for studying boundary value problems for connecting orbits in partial differential equations.
• [05270] Validated dynamics in neural networks: towards chaos
  • Format : Talk at Waseda University
  • Author(s) :
    • Elena Queirolo (TUM)
  • Abstract : Neural networks, a class of machine learning algorithms, can be interpreted as dynamical systems an d can be studied by dynamical techniques. Here, we use validation techniques to understand how the reliability of the algorithm relates to dynamical behaviours. In particular, we want to investigate the co nnection between chaos and reliability. First, we prove or disprove the existence of chaos in a given neural net, then we draw behavioural conclusions based on its existence.

MS [00621] Frontiers of Collaboration with Industry: Succeeding through Failure

room : G406

• [02914] Development of a CNN-Based Model for Car Classification and Damage Detection from car accidents
  • Format : Talk at Waseda University
  • Author(s) :
    • Busayamas pimpunchat (King Mongkut’s Institute of Technology Ladkrabang)
  • Abstract : This study aimed to develop a convolutional neural network (CNN)-based model for car classification and damage detection from car accidents. The research found that the model was highly accurate in classifying the position of a single car and detecting damage and the model's performance in detecting multiple cars, a modified version of the Hough Transform algorithm was used to improve. The study's findings can help insurance companies analyze car damage and introduce relevant sections in vehicle regulations.
• [03805] Failure and Success for Bauxite Moisture Measurement with Microwaves
  • Format : Talk at Waseda University
  • Author(s) :
    • Mark Joseph McGuinness (Victoria University of Wellington)
    • Lata I Paea (University of the South Pacific)
    • Sione Paea (University of the South Pacific)
  • Abstract : The weight of bauxite ore is strongly dependent on moisture content. A microwave analyser measures phase and attenuation in real time, to infer moisture content, which directly impacts the price paid per tonne. Simple linear models fail to explain the highly nonlinear dependence on bauxite depth that is seen in attenuation data. Motivated by this failure, we develop a successful four-layer model that allows multiple reflections at interfaces between ore and air.
• [02161] The UniSA Mathematics Clinic: Renewables, defence, mining, drones, and justice
  • 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. Clinic projects give students professional skills, experience, accomplishments, and employability, and generate research progress and publications. But things can go wrong – with sponsors, students, staff, projects, workload, and logistics. How can we minimise things going wrong, and fix them when they do? I’ll offer some case studies, suggestions, and principles, drawn from Clinic experience.
• [01470] Interdisciplinary research using Topological Flow Data Analysis through Math Clinic
  • Format : Talk at Waseda University
  • Author(s) :
    • Takashi Sakajo (Kyoto University)
  • Abstract : Topological Flow Data Analysis "TFDA" is a new way of data analysis based on the classification theory of 2D vector fields. It extracts and quantifies topological features of complex flows from various datasets efficiently. We are organizing a research platform, called Math Clinic, at Kyoto University, where interdisciplinary research with other disciplines including industry has been conducted based on TFDA. In this talk, we will report on the activity and results of the Math Clinic.

contributed talk: CT026

room : G501

[02589] Two scale convergence method in Orlicz setting and application

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G501
• Type : Contributed Talk
• Abstract : We discus extension to Orlicz spaces of two scale convergence method in homogenization and apllication. Reiterated two scale convergence method and unfolding method is also presented in those Space which generilize standard Sobolev spaces and capture more information. We apply Above method on a number of problem including nonlinear degenerated elliptic operator with nonstandart growth.
• Classification : 35B27, 35B40, 35J25, 35J60, 35J70
• Format : Talk at Waseda University
• Author(s) :
  • Joel Fotso Tachago (The University of Bamenda)
  • Joel Fotso Tachago (The University of Bamenda)
  • Hubert Nnang (University of Yaoundé 1)
  • Elvira Zappale (University of Roma 1)

[00218] Characterizations of diffusion matrices in homogenization of nondivergence-form elliptic equations

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G501
• Type : Contributed Talk
• Abstract : We provide characterizations of diffusion matrices A for which the sequence of solutions $(u^{\varepsilon})_{\varepsilon > 0}$ to $-A(x/\varepsilon):D^2 u^{\varepsilon} = f$ in $\Omega$, $u^{\varepsilon} = g$ on $\partial\Omega$, converges to the solution of the homogenized problem with $L^{\infty}$-rate $\mathcal{O}(\varepsilon^2)$ for all sufficiently regular $f,g$. Whereas such diffusion matrices can be characterized via the third-order homogenized tensor, we provide more explicit characterizations and prove an open conjecture posed by Guo and Tran.
• Classification : 35B27, 35B40, 35J25
• Format : Talk at Waseda University
• Author(s) :
  • Xiaoqin Guo (University of Cincinnati)
  • Timo Sprekeler (National University of Singapore)
  • Hung Vinh Tran (University of Wisconsin Madison)

[00976] A Multi-phase Model for Silicon Carbide Production

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G501
• Type : Contributed Talk
• Abstract : We present a multi-phase model to study the reduction of quartz to silicon carbide in a laboratory-scale reactor. We model the transport of gases and solids, and the kinetics of the reactions involved in the reduction process. Through the analysis of the model, we aim to gain a better understanding of the underlying mechanisms driving the reduction of quartz and to identify key parameters that can be controlled to optimize the production of silicon carbide.
• Classification : 35B30, 35E15, 35Q49, 35R37
• Format : Talk at Waseda University
• Author(s) :
  • Brady Metherall (University of Oxford)

[00197] Mathematical analysis of a nonlinear SIS model with effect of migration

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G501
• Type : Contributed Talk
• Abstract : We consider a nonlinear SIS epidemic model with nonlocal disease transmission rate and diffusion in space which is a system of parabolic equations. The existence and uniqueness of steady state are studied using compact and nonsupporting operators, and strongly continuous semigroup theory, respectively. Due to the nonlinearity in the disease transmission rate, proof of the uniqueness of a steady state requires a completely different approach. The linearization around the nontrivial steady state of the model requires the study of a perturbed operator. Spectral analysis is used to study the local stability and the global stability of the steady state.
• Classification : 35B35, 35Q92, 47H10, 92D25
• Format : Talk at Waseda University
• Author(s) :
  • Soumak Nag (University of Hyderabad)
  • Suman Kumar Tumuluri (University of Hyderabad)

[00824] Asymptotics for Some Singular Limits

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G501
• Type : Contributed Talk
• Abstract : The asymptotic behavior of solutions as a small parameter tends to zero is determined for a variety of singular-limit PDEs. In some cases even existence for a time independent of the small parameter was not known previously. New examples for which uniform existence does not hold are also presented. Some of the results are joint work with Samuel Nordmann.
• Classification : 35B25, 35B40
• Format : Online Talk on Zoom
• Author(s) :
  • Steve Schochet (Tel Aviv University)

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

room : G502

• [04388] Decay estimates for a unit cell model of composite materials
  • Format : Talk at Waseda University
  • Author(s) :
    • Shuji Yoshikawa (Oita University)
  • Abstract : We shall introduce decay estimates for a unit cell model of composite materials. The model we study here is the one of toy models, but the result corresponds to the first step of a mixture of transmission and waveguide problems from the viewpoint of PDEs.
• [04211] Effective hydromechanic models for fibre-reinforced hydrogels
  • Format : Talk at Waseda University
  • Author(s) :
    • Michael Eden (Karlstad University)
    • Hari Shankar Mahato (IIT Kharagpur)
  • Abstract : We consider highly heterogeneous two-component media composed of a connected fibre-scaffold with periodically distributed inclusions of hydrogel. While the fibres are assumed to be elastic, the hydromechanical response of hydrogel is modeled via Biot’s poroelasticity. We show that the resulting mathematical problem admits a unique weak solution and investigate the limit behavior of the solutions with respect to a scale parameter characterizing the heterogeneity of the medium.
• [04680] An elastoplastic model with a time-dependent threshold function
  • Format : Talk at Waseda University
  • Author(s) :
    • Yoshiho Akagawa
    • Takeshi Fukao (Ryukoku University)
    • Risei Kano (Kochi University)
  • Abstract : We investigate the well-posedness of an elastoplastic model described by quasi-variational inequalities, applying the abstract theory of evolution equation. The prototype model is introduced by Duvau-Lions. It is characterized by the constraint for the deviatoric part of the stress tensor. In the case when the constraints depend on time and some unknown strain history, then the model represents more realistic phenomena. This is joint work with Risei Kano (Kochi University), and Takeshi Fukao (Ryukoku University).

contributed talk: CT042

room : G601

[00833] Exact controllability for imperfect interface problems

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G601
• Type : Contributed Talk
• Abstract : We study the exact internal and boundary controllability for a second order linear evolution problem defined in a two-component domain. We prescribe a homogeneous Dirichlet condition on the exterior boundary and a jump of the displacement proportional to the conormal derivatives on the interface. This last condition is the mathematical interpretation of an imperfect interface. The results are achieved via a constructive method known as Hilbert Uniqueness Method, HUM for short, introduced by J. -L. Lions. Unlike classical cases, we find lower bounds for the control times depending not only on the geometry of the domain and on the coefficient matrix of our problems but also on the coefficient of proportionality of the jump with respect to the conormal derivatives. References [1] S. Monsurro`, A. K. Nandakumaran, C. Perugia, Exact Internal Con- trollability for a Problem with Imperfect Interface, Appl. Math. Op- tim. (2022), 1-33. [2] S. Monsurro`, A. K. Nandakumaran, C. Perugia, A Note on the Exact Boundary Controllability for an Imperfect Transmission Problem, Ric. Mat. 40 (2021), 1-18.
• Classification : 35LXX, 35QXX
• Format : Talk at Waseda University
• Author(s) :
  • Sara Monsurrò (University of Salerno)

[02619] Interplay of two finite reservoirs in bidirectional system

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G601
• Type : Contributed Talk
• Abstract : Motivated by the interplay of multiple species in several real world transport processes, we propose a bidirectional totally asymmetric simple exclusion process with two finite reservoirs regulating the inflow of oppositely directed particles corresponding to two different species. The system’s stationary characteristics such as densities, currents, etc., are investigated using a theoretical framework based on mean-field approximation and are supported by extensive Monte Carlo simulations. The impact of species, quantified by filling factor, has been comprehensively analyzed.
• Classification : 35Lxx, 70Exx, 70Lxx, 37Axx
• Format : Talk at Waseda University
• Author(s) :
  • Ankita Gupta (Indian Institute of Technology Ropar)
  • Bipasha Pal (Stockholm University)
  • Arvind Kumar Gupta (Indian Institute of Technology Ropar)

[02013] An Accelerated Iteration for Finding Extremal Solutions of Discrete-Time Algebraic Riccati Equations

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G601
• Type : Contributed Talk
• Abstract : Algebraic Riccati equations (AREs) have been extensively applied in linear optimal control problems and many efficient numerical methods were developed. The stabilizing (or almost stabilizing) solution has attracted the most attention among all Hermitian solutions of the ARE in the past works. Nevertheless, it is an interesting and challenging issue in finding the extremal solutions of AREs which play an important role in the applications. The contribution of this paper is twofold. Firstly, the existence of these extremal solutions is established under the framework of fixed-point iteration. Secondly, an accelerated fixed-point iteration (AFPI) based on the semigroup property is developed for computing four extremal solutions of the discrete-time algebraic Riccati equation. In addition, we prove that the convergence of the AFPI is at least R-suplinear with order $r>1$ under some mild assumptions. Numerical examples are shown to illustrate the feasibility and accuracy of the proposed algorithm.
• Classification : 39B12, 39B42, 65H05, 15A24
• Author(s) :
  • Chun-Yueh Chiang (Center for General Education, National Formosa University)
  • Hung-Yuan Fan (National Taiwan Normal University )

[02322] Low discrepancy point sets inspired by Sudoku hypercubes

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G601
• Type : Contributed Talk
• Abstract : Monte Carlo methods are effective to avoid the "Curse of Dimensionality," while not perfect since their convergences are late. To overcome the weakness, quasi-Monte Carlo methods have been developed. Some of the methods use low discrepancy point sets called $(T, M, S)$-nets. In this talk, I present a new construction procedure of $(T, M, S)$-nets from orthogonal arrays as an application of the extension of Sudoku to higher dimensions named Sudoku hypercubes.
• Classification : 05B15, 65C05
• Format : Talk at Waseda University
• Author(s) :
  • Shigetaka Taga (University of Tsukuba)

[02266] Constructing ternary quasigroups possessing properties of parastrophic orthogonality

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @G601
• Type : Contributed Talk
• Abstract : A set of $\ell$ orthogonal $n$-ary operations or hypercubes of order $m$ is equivalent to an $(\ell,m^n,\ell-n+1)$ maximum distance separable or MDS code. Consequently, the problem of constructing MDS codes can be reduced to constructing orthogonal operations. We research constructing a ternary medial quasigroup possessing parastrophic orthogonality property. A necessary and sufficient condition that the quasigroup is self-orthogonal, strongly self-orthogonal or totally parastrophically orthogonal is that each polynomial of a certain set is invertible-valued.
• Classification : 05B15, 20N05
• Format : Online Talk on Zoom
• Author(s) :
  • Fedir Sokhatsky (Vasyl` Stus Donetsk National University)
  • Iryna Fryz (Vasyl` Stus Donetsk National University)

MS [02219] Pattern formation and propagation in reaction-diffusion systems on metric graphs

room : G602

• [05005] Invasion analysis for population dynamics models on simple metric graphs
  • Format : Talk at Waseda University
  • Author(s) :
    • Satoru Iwasaki (Osaka University)
    • Harunori Monobe (Osaka Metropolitan University)
  • Abstract : We are concerned with invasion processes of biological species in network shaped domains, that is metric graphs. In our model, invasions of biological species are restricted by some traps. In this presentation, we report the difference between results of one-dimensional domains case and those of metric graphs case. Particularly, in metric graphs case, we know that vanishing occurs with less traps than one-dimensional case due to an effect of junctions in metric graphs.
• [02969] Propagation phenomena of Fisher-KPP equation in a shifting environment
  • Format : Talk at Waseda University
  • Author(s) :
    • Jong-Shenq Guo (Tamkang University)
  • Abstract : In this talk, we shall discuss the propagation phenomena of the Fisher-KPP equation with a shifting intrinsic growth rate. We divide the heterogeneous shifting term into two different classes, one is the devastating case and the other is the advantageous case. We shall present some results on the existence of forced waves and the spreading dynamics for solutions with compactly supported initial data.
• [03115] Pulse dynamics for reaction-diffusion systems on various metric graphs
  • Format : Talk at Waseda University
  • Author(s) :
    • Shin-Ichiro Ei (Hokkaido University)
    • Haruki Shimatani (Hokkaido University)
  • Abstract : In this talk, we give pulse dynamics for reaction-diffusion systems on various metric graphs. In particular, we analyze the behavior of the pulse solutions by deriving an equation of the motion. Note an equation of the motion is an expression for the time evolution of the positions of pulse solutions. In the same way, we will also discuss front dynamics for reaction-diffusion systems on various metric graphs.
• [03288] Reaction-advection-diffusion equations over simple graphs
  • Format : Talk at Waseda University
  • Author(s) :
    • Bendong Lou (Shanghai Normal University)
  • Abstract : I will talk about the dynamical behavior of a species spreading in a river network, which is modeled by advective diffusion equations over simple graphs with Fisher-KPP or bistable reactions. Denote by $c_*$ the (minimal) speed of the traveling waves of the corresponding equations without advections, I will present the long time behavior for the solutions in the special case where the water flow speed in upstream is larger than $c_*$ and that in downstream is smaller than $c_*$, which includes washing out, persistence at carrying capacity or persistence below carrying capacity. (joint works with Y. Du, R. Peng, M. Zhou, Y. Morita).

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

room : G605

• [01894] Highly Stable Lead-Free Magnetic Perovskite semiconductors
  • Format : Online Talk on Zoom
  • Author(s) :
    • Shakeel Ahmad Khandy (Zhejiang University)
  • Abstract : Lead Free Halide Perovskites play a key role in Solar cell, LED, nondestructive bioimaging, long-wave communications, and medical care applications as they emit in the broader regions of spectrum from near-infrared region to visible range. Cs2MoX6 (X=Cl,Br) as key members of the luminescent family, have been reported to emit light in ultraviolet and visible regions. Both these systems grow in cubic phase and are stable under thermal, mechanical and dynamical constraints of density functional theory. In addition, the ferromagnetic interactions of Mo with halide p-states create a total magnetic moment of 2 mB, thus enabling another degree of freedom to play with
• [02416] CFD of impingement over a curved surface by equilaterally staggered jets
  • Format : Online Talk on Zoom
  • Author(s) :
    • Alankrita Singh (Indian Institute of Technology Roorkee)
  • Abstract : The equilateral staggered arrangement of jets constitutes of a central jet surrounded by four neighboring jets. The concave plate is uniformly heated at constant heat flux of 3 kW/m2. SIMPLE is incorporated for pressure velocity coupling.SST k-ω is used as the turbulence model. The solution is assumed to be converged when sum of the normalized residuals drop to e-5 for momentum, continuity and turbulence equations and e-7 for energy equations. Similar to lampblack visualization results, the CFD results show stretching of flow along the corners of the concave target surface.
• [02634] An application of the Fuzzy inference system to Seismic Damage Prediction
  • Format : Online Talk on Zoom
  • Author(s) :
    • Dr. Champakali Das (Nims University)
    • Dr. Narendra Kumar (Nims University)
    • Dr. Amit Kumar Singh (RBS Engineering College)
  • Abstract : A damage prediction form has been developed by using fuzzy logic techniques. An earthquake caused significant damage to any building. The results of damage prediction must be used as the basis for a disaster preparedness plan if loss of life and property is to be reduced. Fuzzy logic offers a more unified strategy for addressing earthquake damage prediction difficulties because of the interconnectedness of the key components and the ambiguity of the ideas at play.

MS [00733] Compressible fluid dynamics and related PDE topics

room : G606

• [01716] Global solutions on compressible Euler and Euler-Poisson equations
  • Format : Online Talk on Zoom
  • Author(s) :
    • Yong Wang (Academy of Mathematics and System Sciences, CAS, China)
  • Abstract : I will talk some results on the global existence of solutions to compressible Euler and Euler-Poisson of large intial data with spherical symmetry.
• [01715] Global solutions on compressible Euler and Euler-Poisson equations
  • Format : Online Talk on Zoom
  • Author(s) :
    • Yong Wang (Academy of Mathematics and System Sciences, CAS, China)
  • Abstract : I will talk some results on the global existence of solutions to compressible Euler and Euler-Poisson of large intial data with spherical symmetry.
• [01776] Some recent results on compressible Navier-Stokes equations
  • Format : Talk at Waseda University
  • Author(s) :
    • Jing Li (AMSS, Chinese Academy of Sciences)
  • Abstract : We investigate the barotropic compressible Navier-Stokes equations with slip boundary conditions in a three-dimensional (3D) simply connected bounded domain, whose smooth boundary has a finite number of two-dimensional connected components. For any adiabatic exponent bigger than one, after obtaining some new estimates on boundary integrals related to the slip boundary conditions, we prove that both the weak and classical solutions to the initial-boundary-value problem of this system exist globally in time provided the initial energy is suitably small. Moreover, the density has large oscillations and contains vacuum states. Finally, it is also shown that for the classical solutions, the oscillation of the density will grow unboundedly in the long run with an exponential rate provided vacuum appears (even at a point) initially.
• [03229] Hidden structures behinds the compressible Navier-Stokes equations and its applications to the corresponding models
  • Format : Online Talk on Zoom
  • Author(s) :
    • Xiangdi Huang (Academy of Mathematics and Systems Science)
  • Abstract : In this talk, we will review the past developments on the solutions of the compressible Navier-Stokes equations and reveal the three hidden structures which linked the weak solution to the strong one. Based on these observations, we proved the Nash's conjecture in 1958s and establish global exsitence theory for both isentropic and heat-conductive compressible Navier-Stokes equations. Moreover, for the 3D compressible Navier-Stokes equations, we will show the existence of local weak solutions with higher regularity and local strong solutions with lower regularity. Also, we will mention the recent results on the blowup of the local strong solutions to the MHD equations in finite time and global existence of weak solutions of the compressible Navier-Stokes equations in bounded domains under Dirichlet boundary conditions.

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

room : G701

• [01910] Why Spectral Methods are preferred in PDE Eigenvalue Problems?
  • Format : Talk at Waseda University
  • Author(s) :
    • Zhimin Zhang (CSRC & WSU)
  • Abstract : When approximating PDE eigenvalue problems by numerical methods such as finite difference and finite element, it is common knowledge that only a small portion of numerical eigenvalues are reliable. As a comparison, spectral methods may perform extremely well in some situation, especially for 1-D problems. In addition, we demonstrate that spectral methods can outperform traditional methods and the state-of-the-art method in 2-D problems even with singularities.
• [01726] High-precision guaranteed eigenvalue bounds using higher order finite elements and graded meshes
  • Format : Talk at Waseda University
  • Author(s) :
    • Xuefeng LIU (Niigata University)
  • Abstract : The projection residue error-based eigenvalue bound proposed by the author has a drawback that it is influenced by the worst-case projection error and is not able to take the advantage of non-uniform meshes such as graded meshes. To address these issues, we propose a new method based on the Kato-Lehmann-Goerisch theorem to obtain high-precision eigenvalue bounds that take full advantage of higher-order FEMs, graded meshes, and possible strong regularities of eigenfunctions.
• [01925] Comparison of guaranteed lower eigenvalue bounds with three skeletal methods
  • Format : Talk at Waseda University
  • Author(s) :
    • Emilie Pirch (Friedrich-Schiller-Universität Jena)
    • Carsten Carstensen (Humboldt-Universitaet zu Berlin )
    • Benedikt Gräßle (Humboldt-Universität zu Berlin)
  • Abstract : The focus of this talk is the comparison of three specially tailored skeletal hybrid schemes which provide direct guaranteed lower eigenvalue bounds (GLB) for the Dirichlet eigenvalue problem of the Laplacian. While the scheme presented in (Carstensen-Zhai-Zhang2020) has established the groundwork with a first formulation of the conditions under which GLB can be computed with a hybridized discontinuous Galerkin (HDG) method, a further development in (Carstensen-Ern-Puttkammer2021) results in a modified hybrid-high order method with a simplified stabilization term. However, it involves two parameters whose choice can be unclear due to stability estimates with constants which depend on the polynomial degree $p$ of the approximation spaces and numerical computations show a lack of robustness. (Carstensen-Grässle-Tran2022,subm.) presents a different stabilization which uses a $p$-robust parameter. Numerical examples for all three methods and various polynomial degrees with optimal orders of convergence will be shown in this talk. The details of the qualitative differences in the computation of GLB and possible further practical improvements will be discussed.
• [02081] Novel spectral methods using multivariate Muntz polynomials/functions for Schrodinger eigenvalue problems with singular potentials
  • Format : Talk at Waseda University
  • Author(s) :
    • Huiyuan Li (Institute of Software Chinese Academy of Sciences)
  • Abstract : In this talk, we first introduce multivariate Muntz ball polynomials and Muntz Hermite functions, and then propose novel spectral methods for solving the eigenvalue problems of the Schrodinger operators $[-\Delta + c/|x|^2] + z |x|^{q/p}$ and $-\nabla\cdot (|x|^{2\mu} \nabla) + c |x|^{2\mu-2}$. The Muntz polynomials/functions are tailored to fit the singularities of the eigenfunctions and are orthogonal with respect to the inner product associated with the underlying Schrodinger operator. Numerical experiments demonstrate the efficiency and the exponential order of convergence of our methods, and validate the superiority over other methods.

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

room : G702

• [03933] Analytical approaches to the problem of emergence arising in systems of collective behavior
  • Format : Online Talk on Zoom
  • Author(s) :
    • Roman Shvydkoy (University of Illinois at Chicago)
  • Abstract : Emergence is a phenomenon of formation of collective outcomes in systems where communications between agents has local range. For a wide range of applications, such as swarming behavior of animals or exchange of opinions between individuals, such outcomes result in a globally aligned state or congregation of aligned clusters.  The classical result of Cucker and Smale states that alignment is unconditional in flocks that have global communication with non-integrable radial tails. Proving a similar statement for purely local interactions is a challenging mathematical problem.  In this talk we will overview three programs of research directed on understanding the emergent phenomena: statistical approach to generic alignment for agent-based systems, kinetic approach based on relaxation and hypocoercivity, and hydrodynamic models incorporating a novel way of interaction based on topological communication.

MS [00608] Limit behavior and asymptotic properties in fluid mechanics

room : G703

• [01787] Homogenization of nonstationary incompressible viscous non-Newtonian flows
  • Format : Talk at Waseda University
  • Author(s) :
    • Yong Lu (NANJING UNIVERSITY)
    • Zhengmao Qian (NANJING UNIVERSITY)
  • Abstract : We consider the homogenization of the nonstationary incompressible viscous non-Newtonian fluid flows in a domain perforated with a large number of tiny holes, where the size of the holes is proportional to the mutual distance of the holes, and the stress tensor satisfies the Carreau-Yasuda law. Darcy's law is derived in the limit as the size of holes goes to zero and the number of holes goes to infinity simultaneously.
• [05572] Homogenization of compressible Navier-Stokes in critically perforated domains in Limit behavior and asymptotic properties in fluid mechanics
  • Format : Talk at Waseda University
  • Author(s) :
    • Peter Bella (TU Dortmund)
    • Friederike Lemming (TU Dortmund)
    • Roberta Marziani (TU Dortmund)
    • Florian Oschmann (Czech Academy of Sciences)
  • Abstract : We consider homogenization of the time-dependent compressible Navier-Stokes equations in the low Mach number regime in critically periodically perforated domains. In analogy to a classical result of Allaire (ARMA 90) for the incompressible fluids, we obtain in the limit the incompressible Navier-Stokes system with an additional Brinkman friction form.
• [05422] Existence of weak solutions and hard-congestion limit in the dissipative Aw-Rascle system
  • Format : Online Talk on Zoom
  • Author(s) :
    • Ewelina Zatorska (Imperial College London)
    • Nilasis Chaudhuri (Imperial College London)
  • Abstract : In this talk I am going to present the dissipative Aw-Rascle model of evolution of congestions. I will first explain its connection with other models in fluid mechanics (compressible Euler and Navier-Stokes) and present our progress on the existence theory. In the second part of my talk I will focus on discussing a singular limit passage leading to the so-called "hard-congestion" system.
• [01575] $\Gamma$-convergence of nearly incompressible fluids
  • Format : Talk at Waseda University
  • Author(s) :
    • Peter Bella (TU Dortmund)
    • Eduard Feireisl (Czech Academy of Sciences)
    • Florian Oschmann (Czech Academy of Sciences)
  • Abstract : We consider the time-dependent compressible Navier–Stokes equations in the low Mach number regime in a family of domains $\Omega_\varepsilon \subset \mathbb{R}^d$ converging in the sense of Mosco to a domain $\Omega \subset \mathbb{R}^d, \ d \in \{2,3\}$. We show the limit is the incompressible Navier–Stokes system in $\Omega$. This is joint work with Peter Bella $($TU Dortmund$)$ and Eduard Feireisl $($CAS$)$.

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

room : G704

• [02028] On Quantum Speedups for Nonconvex Optimization via Quantum Tunneling Walks
  • Format : Online Talk on Zoom
  • Author(s) :
    • Yizhou Liu (MIT)
    • Weijie J. Su (University of Pennsylvania)
    • Tongyang Li (Peking University)
  • Abstract : Classical algorithms are often not effective for solving nonconvex optimization problems where local minima are separated by high barriers. In this paper, we explore possible quantum speedups for nonconvex optimization by leveraging the global effect of quantum tunneling. Specifically, we introduce a quantum algorithm termed the quantum tunneling walk (QTW) and apply it to nonconvex problems where local minima are approximately global minima. We show that QTW achieves quantum speedup over classical stochastic gradient descents (SGD) when the barriers between different local minima are high but thin and the minima are flat. Based on this observation, we construct a specific double-well landscape, where classical algorithms cannot efficiently hit one target well knowing the other well but QTW can when given proper initial states near the known well. Finally, we corroborate our findings with numerical experiments.
• [02822] Quantum dynamics simulation and its application to Hamiltonian learning
  • Format : Online Talk on Zoom
  • Author(s) :
    • Di Fang (Duke University)
  • Abstract : Recent years have witnessed tremendous progress in developing and analyzing quantum algorithms for quantum dynamics simulation (Hamiltonian simulation). The accuracy of quantum dynamics simulation is usually measured by the error of the unitary evolution operator in the operator norm, which in turn depends on the operator norm of the Hamiltonian. However, the operator norm measures the worst-case scenario, while practical simulation concerns the error with respect to a given initial vector or given observables at hand. In this talk, we will discuss a few ways to weaken the strong operator norm dependence in quantum simulation tasks by taking into account the the initial condition and observables. We then discuss how such analysis can be applied in the setting of Hamiltonian learning. Using a Hamiltonian reshaping technique, we propose a first learning algorithm to achieve the Heisenberg limit for efficiently learning an interacting N-qubit local Hamiltonian.

MS [00563] PDE's on Mathematical Physics and Biology

room : G709

• [03153] Stable standing waves for a Schrödinger system with nonlinear chi^3 response
  • Format : Talk at Waseda University
  • Author(s) :
    • Tatsuya Watanabe (Kyoto Sangyo University)
  • Abstract : In this talk, we consider standing wave solutions for a certain nonlinear Schrodinger system which appears in nonlinear optics. This two-component system contains a cubic nonlinear term which is called $\chi^3$-interaction, and has a strong coupling on one side only. Oliveira-Pastor (2021) showed the existence of ground state solutions for the corresponding stationary problems, and investigated their stability and instability. In our study, by considering the solvability of a constraint minimization problem, we show the existence of stable standing wave solutions. We also investigate the correspondence between minimizers and ground state solutions. This work is based on joint research with Mathieu Colin (University of Bordeaux).
• [03664] Critical nonlocal problems driven by the fractional Laplacian
  • Format : Online Talk on Zoom
  • Author(s) :
    • Raffaella Servadei (Università degli Studi di Urbino Carlo Bo)
  • Abstract : Critical problems are particularly relevant for their relations with many applications where a lack of compactness occurs. The fractional Laplacian operator appears in concrete applications in many different fields. This is one of the reason why, recently, nonlocal fractional problems are widely studied in the literature. Aim of this talk is to discuss some recent results about existence and multiplicityof solutions for fractional nonlocal equations with critical growth assumptions on the nonlinear term.
• [04405] Variational and topological methods on non-compact Randers spaces
  • Format : Online Talk on Zoom
  • Author(s) :
    • Giovanni Molica Bisci (University of Urbino Carlo Bo)
  • Abstract : Motivated by a wide interest in the literature, the leading purpose of this talk is to present some recent abstract results on non-compact Randers spaces and their applications to quasilinear elliptic equations. The main approach is based on novel abstract Sobolev embedding results as well as on some variational and topological methods.

MS [00247] Interfaces and Free Boundaries in Fluid Mechanics and Materials Science

room : G710

• [02095] On the notion of generalized mean curvature flow
  • Format : Talk at Waseda University
  • Author(s) :
    • Yoshihiro Tonegawa (Tokyo Institute of Technology)
  • Abstract : I describe some new aspects of generalized notion of mean curvature flow which are prompted by various attempts to prove the existence, uniqueness and regularity. The main tool comes from geometric measure theory which allows treatments of singular geometric objects necessary to deal with the weak formulation of mean curvature flow.
• [03166] Coarsening phenomena in the network flow
  • Format : Talk at Waseda University
  • Author(s) :
    • Alessandra Pluda (University of Pisa)
  • Abstract : A network is a 1-dimensional connected set in the plane composed of a finite number of curves that meet at their endpoints in junctions. The flow by curvature of networks has been introduced in mathematical materials science to model the evolution of polycrystals. We would like to formalise a coarsening behavior, suggested by numerical simulations. I will present the mathematical tools developed to describe this evolution and an argument which supports the coarsening behavior.
• [03048] Uniqueness and stability of multiphase mean curvature flow beyond a singular time: the case of the shrinking circle
  • Format : Talk at Waseda University
  • Author(s) :
    • Alice Marveggio (Institute of Science and Technology Austria (ISTA))
    • Julian Fischer (Institute of Science and Technology Austria (ISTA))
    • Maximilian Moser (Institute of Science and Technology Austria (ISTA))
    • Sebastian Hensel (Hausdorff Center for Mathematics, University of Bonn)
  • Abstract : The evolution of a network of interfaces by mean curvature flow features the occurrence of topology changes and geometric singularities. As a consequence, classical solution concepts for mean curvature flow are in general limited to short-time existence theorems, which include singular times only for some stable shrinkers such as the circle. At the same time, the transition from strong to weak solution concepts (e.g. Brakke solutions) may lead to non-uniqueness of solutions. Following the relative energy approach à la Fischer-Hensel-Laux-Simon and introducing a suitable notion of gradient-flow calibration for a shrinking circle, we prove a quantitative stability estimate holding up to the singular time. This implies a weak-strong uniqueness principle for weak BV solutions to planar multiphase mean curvature flow beyond a specific class of singularities. Furthermore, we expect our method to have further applications to other types of shrinkers, as well as to prove quantitative convergence of diffuse-interface (Allen-Cahn) approximations for mean curvature flow.
• [02872] Matrix-valued Allen–Cahn equation and the Keller–Rubinstein–Sternberg problem
  • Format : Talk at Waseda University
  • Author(s) :
    • Mingwen Fei
    • Fanghua Lin (Courant Institute of Mathematical Science, New York University)
    • Wei Wang (Zhejiang University)
    • Zhifei Zhang (Peking University)
  • Abstract : In this talk, we consider the sharp interface limit of a matrix-valued Allen-Cahn equation. We show that the sharp interface system is a two-phases flow system: the interface evolves according to the motion by mean curvature; in the two bulk phase regions, the solution obeys the heat flow of harmonic maps with values in $n\times n$ orthogonal matrices with determinant $+1$ and $-1$ respectively; on the interface, the phase matrices in two sides satisfy a novel mixed boundary condition. The above result provides a solution to the Keller-Rubinstein-Sternberg's problem in the $O(n)$ setting. Our proof relies on two key ingredients. First, in order to construct the approximate solutions by matched asymptotic expansions, as the standard approach does not seem to work, we introduce the notion of quasi-minimal connecting orbits. They satisfy the usual leading order equations up to some small higher order terms. In addition, the linearized systems around these quasi-minimal orbits needs to be solvable up to some good remainders. These flexibilities are needed for the possible ``degenerations" and higher dimensional kernels for the linearized operators on matrix-valued functions due to intriguing boundary conditions at the sharp interface. The second key point is to establish a spectral uniform lower bound estimate for the linearized operator around approximate solutions. To this end, we introduce additional decompositions to reduce the problem into the coercive estimates of several linearized operators for scalar functions and some singular product estimates which are accomplished by exploring special cancellation structures between eigenfunctions of these linearized operators.

MS [00237] Recent progress in multiscale modeling and computational methods in material sciences

room : G801

• [05350] Multi-scale modeling and simulations for two-phase flow with moving contact lines
  • Format : Talk at Waseda University
  • Author(s) :
    • Xianmin Xu (Chinese Academy of Sciences)
  • Abstract : Two phase flow with moving contact lines is very difficult to model and simulate due to its multi-scale nature. The slipness of the fluid molecules on solid substrates must be take into account near the contact line in a continuum model since the standard no slip boundary condition induces infinite energy dissipations. The microscopic roughness and inhomogeneity of the substrates make the problem even more challenging. In this talk, we will present some recent efforts to develop coarse-graining boundary condition and efficient numerical methods on the problem. In particular, we show that the Onsager principle can be used as an approximation tool to derive effective models for the dynamical multiscale problem.
• [04103] Energy stable methods for two-phase phase-field surfactant model
  • Format : Talk at Waseda University
  • Author(s) :
    • Zhen Zhang (Southern University of Science and Technology)
  • Abstract : We develop energy stable and bound preserving schemes for phase-field surfactant model with moving contact lines. The desired properties of the schemes are rigorously proved. We numerically validate the accuracies of the schemes and apply them in simulating droplet impact problems. Qualitative agreements with experiments are obtained. Moreover, surfactants are observed to have effects on enhancing droplet deformation and reducing dissipations.
• [01396] Construction and Analysis for the Coupling Method of Atomistic and Higher Order Continuum Models
  • Format : Talk at Waseda University
  • Author(s) :
    • Hao Wang (Sichuan University)
    • Yangshuai Wang (University of British Columbia)
  • Abstract : Atomistic to continuum coupling methods have been widely used in the numerical simulation of crystal lattice with defects. In this talk, we present the construction and analysis of a coupling scheme that combines the atomistic model with a higher order continuum with sharp interface. We show that such scheme is of higher order of accuracy compared with existing models that couples the atomistic model with the classic Cauchy-Born model.
• [01316] A domain decomposition method for the Poisson-Boltzmann solvation model
  • Format : Talk at Waseda University
  • Author(s) :
    • Chaoyu Quan (Southern University of Science and Technology)
  • Abstract : A nonoverlapping domain decomposition method is studied for the linearized Poisson--Boltzmann equation, which is essentially an interior-exterior transmission problem with bounded interior and unbounded exterior. This problem is different from the classical Schwarz alternating method for bounded nonoverlapping subdomains well studied by Lions in 1990, and is challenging due to the existence of unbounded subdomain. To obtain the convergence, a new concept of interior-exterior Sobolev constant is introduced and a spectral equivalence of related Dirichlet-to-Neumann operators is established afterwards. We prove rigorously that the spectral equivalence results in the convergence of interior-exterior iteration. Some numerical simulations are provided to investigate the optimal stepping parameter of iteration and to verify our convergence analysis.

MS [00507] Stochastic Dynamical Systems and Applications

room : G802

• [04528] Approximation of nonlinear filtering for multiscale McKean-Vlasov stochastic differential equations
  • Format : Talk at Waseda University
  • Author(s) :
    • Huijie Qiao (Southeast University)
    • Wanlin Wei (Southeast University)
  • Abstract : The work concerns approximation of nonlinear filtering for multiscale McKean-Vlasov stochastic differential equations. First of all, by a Poisson equation we prove an average principle. Then we define nonlinear filtering of the origin multiscale equations and the average equation, and again by the Poisson equation show approximation between nonlinear filtering of the slow part for the origin multiscale equations and that of the average equation.
• [04629] On the WKB approximation of confluent hypergeometric systems
  • Format : Talk at Waseda University
  • Author(s) :
    • Xiaomeng Xu
  • Abstract : This talk studies the WKB approximation of the linear meromorphic systems of Poncaré rank 1 via the isomonodromy approach. It gives a characterization of the WKB approximation via the periods on the underlying spectral curves. It also unveils a relation between the WKB approximation, the Cauchy interlacing inequality, cluster algebras and so on. It is based on a joint work with Anton Alekseev, Andrew Neitzke and Yan Zhou.
• [04570] Global stability of stochastic functional differential equations
  • Format : Talk at Waseda University
  • Author(s) :
    • Xiang Lyu (Shanghai Normal University)
  • Abstract : This paper gives a criterion for the existence of a stationary solution for a class of semilinear stochastic functional differential equations with additive white noise and its global stability. To be more precise, we show that the infinite-dimensional stochastic flow possesses a unique globally attracting random equilibrium in the state space of continuous functions, which produces the globally stable stationary solution.
• [04648] Averaging principle for slow-fast systems of stochastic PDEs with rough coefficients
  • Format : Online Talk on Zoom
  • Author(s) :
    • Yichun Zhu (University of Maryland, College Park)
    • Sandra Cerrai (University of Maryland, College Park)
  • Abstract : In this paper, we consider a class of slow-fast systems of stochastic partial differential equations where the nonlinearity in the slow equation is not continuous and unbounded. We first provide conditions that ensure the existence of a martingale solution. Then we prove that the laws of the slow motions are tight, and any of their limiting points is a martingale solution for a suitable averaged equation. Our results apply to systems of stochastic reaction-diffusion equations where the reaction term in the slow equation is only continuous and has polynomial growth.

MS [00506] Inverse Problems for Anomalous Diffusion

room : G808

• [01356] Coefficient identification space-fractional equation with Abel type operators
  • Format : Online Talk on Zoom
  • Author(s) :
    • Barbara Kaltenbacher (University of Klagenfurt)
  • Abstract : We consider the inverse problem of recovering an unknown, spatially-dependent coefficient $q(x)$ from the fractional order equation $\mathbb{L}_\alpha u = f$ defined in a two-dimensional spatial domain from boundary information. Here $\mathbb{L_\alpha} ={D}^{\alpha_x}_x +{D}^{\alpha_y}_y +q(x)$ contains fractional derivative operators based on the Abel fractional integral. We develop uniqueness and reconstruction results and show how the ill-conditioning of this inverse problem depends on the geometry of the region and the fractional powers $\alpha_x$ and $\alpha_y$.
• [04481] Inverse problems for simultaneous determination of several scalar parameters and source factors in anomalous diffusion equations
  • Format : Online Talk on Zoom
  • Author(s) :
    • Jaan Janno (Tallinn University of Technology)
  • Abstract : We consider inverse problems for anomalous diffusion equations where unknowns are orders of multiterm fractional time derivatives/multiterm fractional Laplacians or kernels of distributed fractional time derivatives/distributed fractional Laplacians. Along with these quantities an unknown is also a space-dependent or time-dependent source factor. We prove uniqueness for simultaneous determination of these quantities form final or boundary data.
• [03427] Parameter inverse problem for coupled time-fractional diffusion systems
  • Format : Talk at Waseda University
  • Author(s) :
    • Yikan Liu (Hokkaido University)
  • Abstract : This talk is concerned with determining fractional orders in a coupled system of time-fractional diffusion equations. Defining the mild solution, we first establish fundamental unique existence of the solution, which mostly inherit those of a single equation. Owing to the coupling effect, we obtain the uniqueness for determining all orders by the single point observation of a single component of the solution.
• [04183] Identification of potential in diffusion equations from terminal observation
  • Format : Online Talk on Zoom
  • Author(s) :
    • Zhidong Zhang (Sun Yat-sen University)
  • Abstract : We consider an inverse potential problem in a (sub)diffusion equation. We construct a monotone operator, one of whose fixed points is the unknown potential. The uniqueness of the identification is proved. Next, a fixed point iteration is applied to reconstruct the potential. We prove the linear convergence of the iterative algorithm and present a thorough error analysis for the reconstructed potential. Numerical experiments are provided to illustrate and complement our theoretical analysis.

MS [02277] New regularizing algorithms for solving inverse and ill-posed problems

room : G809

• [05628] Regularization of linear inverse problems and neural networks
  • Format : Online Talk on Zoom
  • Author(s) :
    • Sergey Kabanikhin (Sobolev Institute of Mathematics)
  • Abstract : The report will consider methods of numerical regularization of linear inverse problems and neural networks in applications.
• [05627] Applied inverse problems for parabolic equations
  • Format : Online Talk on Zoom
  • Author(s) :
    • Maxim Shishlenin (Sobolev Institute of Mathematics)
  • Abstract : The report will consider inverse problems for parabolic equations in applications such as pharmacodynamics and financial mathematics.
• [02806] Data-Driven Regularization in Variational Data Assimilation from An Ocean Perspective
  • Format : Talk at Waseda University
  • Author(s) :
    • Long Li (Harbin Institute of Technology)
    • Jianwei Ma (Peking University)
  • Abstract : Current machine learning-driven methods make a positive difference to outlook on data assimilation. However, its reliability remains to be studied since little deterministic information from physical laws is involved. In this talk, we will introduce our recent work about the efficient assimilation by the approximation of a deep neural network. The sparsity regularization is employed to improve the well-posedness. Results show the technique is robust for reconstructing the velocity of a fluid with vortex structures.
• [02803] Uniqueness and numerical inversion in the time-domain fluorescence diffuse optical tomography
  • Format : Talk at Waseda University
  • Author(s) :
    • Chunlong Sun (Nanjing University of Aeronautics and Astronautics)
  • Abstract : This work considers the time-domain fluorescence diffuse optical tomography. We recover the distribution of fluorophores in biological tissue by the boundary measurements. With the Laplace transform and the knowledge of complex analysis, we build the uniqueness theorem of this inverse problem. The numerical inversions are considered. We introduce an iterative inversion algorithm under the framework of regularizing scheme.

MS [02499] Machine Learning for dynamics and its applications

room : F308

• [05374] Kernel Flows and Kernel Mode Decomposition for Learning Dynamical Systems from Data
  • Format : Talk at Waseda University
  • Author(s) :
    • Boumediene Hamzi (Caltech)
  • Abstract : Regressing the vector field of a dynamical system from a finite number of observed states is a natural way to learn surrogate models for such systems. We present variants of the method of Kernel Flows as simple approaches for learning the kernel that appear in the emulators we use in our work. First, we will talk about about the method of parametric and nonparametric kernel flows for learning chaotic dynamical systems. We’ll also talk about learning dynamical systems from irregularly-sampled time series as well as from partial observations. We will also introduce the method of Sparse Kernel Flows and apply it to learn 132 chaotic dynamical systems. Finally, we extend the method of Kernel Mode Decomposition to design kernels in view of detecting critical transitions in some fast-slow random dynamical systems. This is joint work with Yang Lu, Xiuwen Sun, Houman Owhadi, Leo Paillet, Naiming Xie
• [05420] Discovery of quasiperiodically driven dynamics using kernel methods
  • Format : Talk at Waseda University
  • Author(s) :
    • Suddhasattwa Das (Texas Tech University)
    • Shaurya Agarwal (University of Central Florida)
    • Shakib Mustavee (University of Central Florida)
  • Abstract : Quasiperiodically driven dynamical systems are nonlinear systems which are driven by some periodic source with multiple base-frequencies. Such systems abound in nature, and are present in data collected from sources such as astronomy and traffic data. Such dynamics decomposes into two components - the driving quasiperiodic source with generating frequencies; and the driven nonlinear dynamics. Analysis of the quasiperiodic part presents the same challenges as classical Harmonic analysis. On the other hand, the nonlinear part bears all the aspects of chaotic dynamics, and possibly carry stochastic perturbations. We present a kernel-based method which provides a robust means to learn both these components. It uses a combination of a kernel based Harmonic analysis and kernel based interpolation technique, to discover these two parts. The technique performs reliably in several real world systems, ranging from analyzing the human heart to traffic data.

MS [01897] New Tools for Nonlinear Time Series Analysis

room : F309

• [03926] Power spectrum estimation for extreme events data
  • Format : Talk at Waseda University
  • Author(s) :
    • Norbert Marwan (Potsdam Institute for Climate Impact Research (PIK))
    • Tobias Braun (Potsdam Institute for Climate Impact Research (PIK))
  • Abstract : The estimation of power spectral density (PSD) of time series is an important task in many quantitative scientific disciplines. However, the estimation of PSD from discrete data, such as extreme event series is challenging. We present a novel approach for the estimation of a PSD of discrete data. Combining the edit distance metric with the Wiener-Khinchin theorem provides a simple yet powerful PSD analysis for discrete time series (e.g., extreme events). This method works directly with the event time series without interpolation or transformation to continuous data. We demonstrate the method's potential on some prototypical examples and on event sequences of atmospheric rivers (AR), narrow filaments of extensive water vapor transport in the lower troposphere. Considering the spatial-temporal event series of ARs over Europe, we investigate the presence of a seasonal cycle as well as periodicities in the multi-annual range for specific regions, likely related to the North-Atlantic Oscillation (NAO).
• [04346] Constructing First Return Maps from Ordinal Partitioning of Time Series
  • Format : Talk at Waseda University
  • Author(s) :
    • Zahra Shahriari (The University of Western Australia)
  • Abstract : We present a robust algorithm for constructing first return maps (FRM) of dynamical systems from time series that does not require embedding. Typically, an FRM is constructed utilizing the time series' maxima or zero-crossings. Our method is based on ordinal partitions, and we use consecutive ordinal symbols to construct the FRM. For each ordinal sequence, we generate a unique FRM and rank them using two entropy-based measures to select the "good" ones.
• [04581] Optimization approaches in analyzing marked point process data
  • Format : Talk at Waseda University
  • Author(s) :
    • Noriyoshi Sukegawa (Hosei University)
    • Shohei Suzuki (Tokyo University of Science)
    • Yoshiko Ikebe (Tokyo University of Science)
    • Yoshito Hirata (University of Tsukuba)
  • Abstract : In this talk, we present an integer programming model for computing a median of a set of marked point processes under an edit distance. The marked point process is a time series of discrete events with marks observed in continuous time. The edit distance is a common metric originated by Victor and Purpura in 1997. We show numerical results on its application in earthquake prediction.
• [02926] Generalized entropies in nonlinear time series analysis
  • Format : Talk at Waseda University
  • Author(s) :
    • Jose M. Amigo (Universidad Miguel Hernandez)
  • Abstract : The concept of entropy plays an important role in both random and deterministic processes. In nonlinear time series analysis, entropy is mostly used to characterize the complexity of the data source. To this end, the concept of Shannon entropy is too rigid, so analysts prefer the more flexible concept of generalized entropy, which fulfills the first three Shannon-Khinchin axioms but not the fourth. These entropies include the Renyi and Tsallis entropies. In my talk I will show that generalized entropies are required to cope with the needs of time series analysis, in particular of symbolic representations with permutations.

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

room : F310

• [05088] Beyond the Painlevé property
  • Format : Talk at Waseda University
  • Author(s) :
    • Rod Halburd (University College London)
  • Abstract : The Painlevé property and associated tests have led to the identification of integrable cases of many families of equations. In this talk I will describe some generalisations of the Painlevé property that allow for the identification of a wider set of integrable equations. Various necessary conditions will be discussed and implemented. Examples from Newtonian and relativistic stellar models will be analysed
• [05195] Constructing non-commutative systems with Pfaffian type solutions
  • Format : Talk at Waseda University
  • Author(s) :
    • Claire Gilson (University of Glasgow)
  • Abstract : In this talk we look to construct non-commutative systems from quasi-determinants of Pfaffian type by considering quasi-determinant identities.
• [03957] Addition formulae for ultradiscrete hafnians
  • Format : Talk at Waseda University
  • Author(s) :
    • Hidetomo Nagai (Tokai University)
  • Abstract : Ultradiscrete hafnian is an ultradiscrete analogue of hafnian, which is signature free pfaffian. In this talk we propose some formulae for the ultradiscrete hafnians with some conditions, which are related to the ultradiscrete soliton solutions.
• [05092] Recent Advances on the Analysis and Applications of Continuous and Discrete Integrable Systems
  • Format : Talk at Waseda University
  • Author(s) :
    • Andrew Hone (University of Kent)
  • Abstract : "New discrete integrable systems from deformed cluster mutations" We describe how to obtain integrable maps by deforming cluster algebra mutations that display Zamolodchikov periodicity. The simplest example is the general Lyness map in 2D, arising as a 2-parameter family of deformations of the cluster algebra of finite type A_2. Results will be presented on integrability of deformed mutations in type A_n, and other finite root systems. This is joint work with J.Grabowski, W.Kim, and T.Kouloukas.

contributed talk: CT063

room : F311

[00512] Rigged Hilbert Space Formulation for Many-Body Quantum Theory

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @F311
• Type : Contributed Talk
• Abstract : The rigged Hilbert space that associates the distribution functions with the Hilbert space is the fundamental one of quantum mechanics to define the bra-ket vectors. Their construction has been attempted mainly for single-particle systems. We are trying to extend the rigged Hilbert space formulation to various realistic quantum systems. In this presentation, we present the result of extending this formulation to quantum many-body systems.
• Classification : 47A70, 81Q10, 81V70
• Format : Talk at Waseda University
• Author(s) :
  • Junichi Takahashi (Waseda University)
  • Shousuke Ohmori (Waseda University)

[00291] Graph Convergence and Iterative Algorithm for a System of Generalized Nonlinear Variational-like Inclusions

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @F311
• Type : Contributed Talk
• Abstract : We focus on the investigation of the problem of finding a common point lying in the solutions set of a system of generalized nonlinear variational-like inclusions and the fixed points set of a total asymptotically nonexpansive mapping. A new iterative algorithm is suggested by employing the concepts of $P$-$\eta$-proximal-point mapping and graph convergence. Convergence of a sequence of above is established. We Prove the strong convergence and stability of the sequence generated by our algorithm.
• Classification : 47H20, Operator theory
• Format : Talk at Waseda University
• Author(s) :
  • Suliman S Al-Homidan (King Fahd University of Petroleum and Minerals)

[02301] Weak Maximum Principle for Nonlocal Boundary Value Problems

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @F311
• Type : Contributed Talk
• Abstract : Throughout the last years, increased attention has been devoted to the investigation of nonlocal models in which points separated by a non-vanishing distance interact with each other. In this talk, we present a weak maximum principle for nonlocal boundary value problems and point out a possible application.
• Classification : 47G20, Analysis of Nonlocal Models
• Format : Talk at Waseda University
• Author(s) :
  • Julia Huschens (Trier University)

[02303] Coupling Of Nonlocal Neumann Problems

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @F311
• Type : Contributed Talk
• Abstract : In nonlocal models points separated by a non-vanishing distance interact with each other. Therefore, domains separated by a non-vanishing distance can be coupled in these models. In this talk, we consider the nonlocal diffusion operator $\mathcal{L}u(x):=\int_{\mathbb{R}^{d}}u(x)-u(y)\gamma(y,x))\,\mathrm{d}y$ and the nonlocal Neumann operator $\mathcal{N} u(y):=\int_{\Omega}(u(y)-u(x))\gamma(x,y)\,\mathrm{d}x$. With these operators we introduce a coupled Neumann problem and we, moreover, consider parabolic nonlocal Neumann equations.
• Classification : 47G20, Analysis of nonlocal models
• Format : Talk at Waseda University
• Author(s) :
  • Michael Vu (University Trier)

[00585] Computational and Optimization Frameworks for Tissue Vascularization in Bioprinted Grafts

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @F311
• Type : Contributed Talk
• Abstract : Template channels within tissue-engineered skin grafts can provide a promising tool for faster microvasculature formation and transport of nutrients to cells outside channels. Developing viable grafts requires the optimal design to support cell viability by controlled channel geometry and biomaterial properties. We discuss the recent advances in creating a robust computational framework to simulate physical and biological phenomena in graft samples. The first computational results will speak for future applications to models using laboratory data.
• Classification : 49-06, 92-10, 76Z05, 92-08, 92C75
• Format : Talk at Waseda University
• Author(s) :
  • Chris Bashur (Florida Institute of Technology)
  • Beste Caner (Florida Institute of Technology)
  • Vladislav Bukshtynov (Florida Institute of Technology)

MS [01040] Optimization and its Applications

room : F312

• [02153] On the approximate purification of mixed strategies in games with infinite action sets
  • Format : Talk at Waseda University
  • Author(s) :
    • Chaowen Yu (Rissho University)
    • Yuhki Hosoya (Chuo University)
  • Abstract : We consider a game in which the action set of each player is uncountable, and show that, from weak assumptions on the common prior, any mixed strategy has an approximately equivalent pure strategy. The assumption of this result can be further weakened if we consider the purification of a Nash equilibrium. Combined with the existence theorem for a Nash equilibrium, we derive an existence theorem for a pure strategy approximated Nash equilibrium under sufficiently weak assumptions. All of the pure strategies we derive in this paper can take a finite number of possible actions.
• [03646] Numerical aspects of finding nonlinear production – consumption equilibrium
  • Format : Talk at Waseda University
  • Author(s) :
    • Igor Griva (George Mason University)
    • Roman A Polyak (George Mason University)
  • Abstract : We present and analyze numerical results obtained by using extra pseudo-gradient (EPG) method on a set of randomly generated nonlinear production – consumption equilibrium (NPCE) problems. The obtained results show that the number of EPG steps required for finding NPCE grows linearly with the number of products of a given economy. The number of arithmetic operations or time required for finding NPCE grows as a cube of the number of products.
• [04476] Envelope theorems in Optimization
  • Format : Talk at Waseda University
  • Author(s) :
    • Joël Blot (Université PParis 1 Panthéon-SorbonneUniversi)
  • Abstract : We present recent results on the Envelope theorems in three chapters of Optimization. First in Static Optimization, secondly in Calculus of Variations and thirdly in Optimal Control Theory. To do that, we provide new results on the continuous dependence of coordiates in a moving frame, on the Hadamard di�erentiability of functionals under the integral form, and on the proof of the Pontryagin principle. Date: November 13, 2022.

MS [00657] Tomographic inverse problems and deep learning techniques

room : F401

• [05264] Ill-posed Inverse problems in Low-dose Dental Cone-beam Computed Tomography
  • Format : Talk at Waseda University
  • Author(s) :
    • Hyoung Suk Park (National Institute for Mathematical Sciences)
    • Chang Min Hyun (Yonsei University)
    • Jin Keun Seo (Yonsei University)
  • Abstract : Dental cone-beam computed tomography (CBCT) has been increasingly being used in various dental fields such as implant/prosthetics, oral and maxillofacial surgery, and orthodontic treatment. It aims to provide high-resolution images with the lowest possible radiation dose at a low cost for equipment. However, this cost-competitive goal makes the inverse problem of dental CBCT more nonlinear and ill-posed. In this presentation, we describe the mathematical structure of an ill-posed nonlinear inverse problem of low-dose dental CBCT and explain the advantages and limitations of the deep learning-based approach for CBCT image reconstruction compared to conventional regularization methods.
• [05265] Machine learning for automatic signal quality assessment in multi-channel electrical impedance-based hemodynamic monitoring
  • Format : Talk at Waseda University
  • Author(s) :
    • Chang Min Hyun (Yonsei University)
  • Abstract : Owing to recent advances in thoracic electrical impedance tomography, a patient's hemodynamic function can be noninvasively and continuously estimated in real-time by surveilling a cardiac volume signal associated with stroke volume and cardiac output. In clinical applications, however, a cardiac volume signal is often of low quality, mainly because of the patient's deliberate movements or inevitable motions during clinical interventions. This talk deals with developing a signal quality indexing method that assesses the influence of motion artifacts on transient cardiac volume signals. We apply divergent machine-learning methods from discriminative-model to manifold learning. The use of machine-learning could be suitable for our real-time monitoring application that requires fast inference and automation as well as high accuracy. In the clinical environment, the proposed method can be utilized to provide immediate warnings so that clinicians can minimize confusion regarding patients' conditions, reduce clinical resource utilization, and improve the confidence level of the monitoring system. Numerous experiments using actual EIT data validate the capability of cardiac volume signals degraded by motion artifacts to be accurately and automatically assessed in real-time by machine learning.
• [05332] Application of AI-based Medical Diagnosis: focusing on tomography
  • Format : Talk at Waseda University
  • Author(s) :
    • Soomin Jeon (Dong-A University)
  • Abstract : In this talk, we will see the various applications of artificial intelligence (AI) based medical diagnosis, focusing on tomography. From data set configuration for AI medical image research using tomography such as PET, X-ray, and X-ray CT, we look at the results of research on training algorithms. We also cover research related to the latest diagnostic technologies such as Alzheimer's disease.
• [05324] Data-driven reconstruction in X-ray CT with provable convergence guarantees
  • Author(s) :
    • Jürgen Frikel (OTH Regensburg)
    • Simon Göppel (University of Innsbruck)
    • Markus Haltmeier (University of Innsbruck)
  • Abstract : Computed tomography (CT) is a widely used imaging technique in various fields including medicine, engineering, and materials science. CT image reconstruction is an ill-posed problem, which means that small errors in the measurements can lead to significant errors in the reconstruction. In order to stabilize the image reconstruction, the use of regularization techniques is crucial. Classical regularization methods (e.g., variational regularization) are known to provide convergent methods, but the resulting reconstructions may not be optimal. On the other hand, regularization strategies based on machine learning methods have been shown to produce better reconstructions, but often lack theoretical convergence guarantees. To address these challenges, we propose a convergent data-driven reconstruction method for x-ray tomography. Our framework consists of two steps, where in a classical regularization is used in the first step and a deep learning approach is used in the second step. Both steps are coupled by integrating data proximity into a network architecture. This integration allows us to leverage the strengths of both approaches while addressing their limitations. Our experimental results demonstrate the effectiveness of our approach in improving the accuracy of CT image reconstruction, while providing convergence guarantees.

MS [00941] Numerical methods for Hamilton-Jacobi equations and their applications

room : F402

• [03726] Neural networks for first order HJB equations and application to front propagation with obstacle terms
  • Format : Talk at Waseda University
  • Author(s) :
    • Olivier Bokanowski (LJLL, University Paris Cité)
    • Olivier Bokanowski (LJLL, University Paris Cité)
    • Averil Prost (Insa Rouen)
    • Xavier Warin (EDF)
  • Abstract : We propose deep neural network schemes for Bellman's dynamic programming principlefor some deterministic optimal control problems,corresponding also to some first-order Hamilton-Jacobi-Bellman equations with an obstacle term.We give an error analysis in an average norm, which is new in this deterministic context. We give several academic numerical examples on front propagation problems with obstacles in order to show the relevance of the approach.
• [03517] A system of of Hamilton-Jacobi equations characterizing geodesic centroidal tessellations
  • Format : Talk at Waseda University
  • Author(s) :
    • Adriano Festa (Politecnico di Torino)
  • Abstract : We introduce a class of systems of Hamilton-Jacobi equations characterizing geodesic centroidal tessellations, i.e. tessellations of domains with respect to geodesic distances where generators and centroids coincide. Typical examples are given by geodesic centroidal Voronoi tessellations and geodesic centroidal power diagrams. An appropriate version of the Fast Marching method on unstructured grids allows computing the solution of the Hamilton-Jacobi system and therefore the associated tessellations. We propose various numerical examples to illustrate the features of the technique.
• [04710] Tropical and multi-level numerical methods for solving optimal control problems
  • Format : Talk at Waseda University
  • Author(s) :
    • Marianne Akian (Inria and CMAP, Ecole polytechnique)
    • Stephane Louis Gaubert (INRIA and CMAP, Ecole polytechnique)
    • Shanqing Liu (CMAP, Ecole polytechnique and Inria)
  • Abstract : We develop and study several numerical approximations and algorithms for computing the solution of Hamilton-Jacobi partial differential equations satisfied by the value function of deterministic optimal control problems over a finite dimensional space. These algorithms combine tropical numerical method or fast-marching method, with a multi-level discretization in a neighborhood of the optimal trajectories. For regular problems, the complexity as a function of precision, can be as for a one-dimensional problem.
• [04939] Exploiting Hamilton-Jacobi-Bellman equations in the representation and evolution of conservative dynamics.
  • Format : Online Talk on Zoom
  • Author(s) :
    • Peter Dower (University of Melbourne)
    • William McEneaney (University of California San Diego)
  • Abstract : Connections between Hamilton's action principle and optimal control are explored in the representation and evolution of conservative dynamics. By associating these dynamics with a Hamilton-Jacobi-Bellman equation or its characteristic system, dynamic programming and verification results are used to construct a fundamental solution and solve inverse problems. On longer time horizons, where the action is not “least”, analogous developments are shown to follow using a notion of “stationary” control. Various applications are highlighted.

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

room : F403

• [03475] Feature Flow Regularization: Improving Structured Sparsity in Deep Neural Networks
  • Author(s) :
    • YUE WU (The Hong Kong University of Science and Technology)
    • YUAN LAN (The Hong Kong University of Science and Technology)
    • Luchan Zhang (Shenzhen University)
    • Yang Xiang (Hong Kong University of Science and Technology)
  • Abstract : Pruning is a model compression method that removes redundant parameters and accelerates the inference speed of deep neural networks while maintaining accuracy. We propose a regularization strategy from a new perspective of evolution of features.  We propose feature flow regularization (FFR) to penalize the length and total absolute curvature of the trajectories, which implicitly increases the structured sparsity of the parameters. The principle is that short and straight trajectories will lead to an efficient network. 
• [04428] Asymptotic-Preserving Neural Networks for Multiscale Time-Dependent Linear Transport Equations
  • Author(s) :
    • Shi Jin (Shanghai Jiao Tong University)
    • Zheng Ma (Shanghai Jiao Tong University)
    • Keke Wu (Shanghai Jiao Tong University)
  • Abstract : In this paper we develop a neural network for the numerical simulation of time-dependent linear transport equations with diffusive scaling and uncertainties. The goal of the network is to resolve the computational challenges of curse-of-dimensionality and multiple scales of the problem. We first show that a standard Physics-Informed Neural Network (PINN) fails to capture the multiscale nature of the problem, hence justifies the need to use Asymptotic-Preserving Neural Networks (APNNs). We show that not all classical AP formulations are directly fit for the neural network approach.We construct a micro-macro decomposition based neural network, and also build in a mass conservation mechanism into the loss function, in order to capture the dynamic and multiscale nature of the solutions. Numerical examples are used to demonstrate the effectiveness of this APNNs.

MS [00385] Origami Engineering (2/2)

room : F411

• [01562] A remark on the foldability of non-simply connected paper
  • Format : Talk at Waseda University
  • Author(s) :
    • Hiroko Murai (Nara Women's University)
    • Akari Iwamura (Nara Women's University)
  • Abstract : It is known that for any simply connected piece of paper $P$, any flat folded state $(f,\lambda)$ of $P$ is realized by a motion from the unfolded state.  In this talk, we show that the above result does not hold if the paper is not simply connected and give some examples.
• [05414] Origami Structures and Materials: Energy Absorption and Impact Mechanics
  • Format : Talk at Waseda University
  • Author(s) :
    • Guoxing Lu (Swinburne University of Technology)
  • Abstract : This presentation introduces energy absorption and impact response of origami inspired structures and metamaterial, which we have recently studied. Several examples of incorporating the concepts of origami will be presented. They include thin-walled structures under axial loading, Miura metamaterials and its variations under quasi-static and dynamic compression and origami sandwich panels under quasi-static loading and ballistic impact. Responses of such materials and structures involve large plastic deformation as well as dynamic effects. For metamaterials, analytical models have been developed to describe the strength and energy absorption capacity. It is assumed that the base material is ductile and can be approximated as a perfectly-plastic material. The analytical model is verified by the numerical simulations as well as quasi-static compression test of a four-sheet origami specimen. Response of such material under impact loading is also investigated and a shock model is proposed for high velocity impact.
• [02536] Platonic solids-based optimization for kirigami honeycomb fabrication of complex structures
  • Author(s) :
    • Junichi Shinoda (Interlocus CO.LTD)
    • Keiko Yamazaki (Meiji University)
    • Ichiro Hagiwara (Meiji University)
    • Luis Diago (Meiji University)
  • Abstract : The aerospace, automotive, and marine industries are heavily reliant on sandwich panels with cellular material cores. In this work, a platonic solids-based optimization algorithm has been developed to select the direction of the cells of the kirigami-honeycomb panel with the smallest waste of materials by rotating the 3D solid model of any shape according to the normal vectors in the platonic solids.
• [02542] Development of beautifully foldable PET bottles
  • Author(s) :
    • Yang Yang (Meiji University)
    • Chie Nara (Meiji University)
    • Ichiro Hagiwara (Meiji University)
  • Abstract : Although many have attempted to develop a PET bottle that is foldable in the axial direction without bending, such bottles are not yet on the market. This is because that although the model with several foldable layers can be folded rather easily without bending, it springs back to almost its original height after compression. Thus, we develop new types of PET bottle with two or three spiral layers to resolve this spring back issue.

MS [00686] Higher-order networks for complex systems

room : F412

• [02960] Hypergraph representation of topological features in complex systems
  • Format : Talk at Waseda University
  • Author(s) :
    • Agnese Barbensi (The University of Melbourne)
  • Abstract : Understanding how a system's behaviour emerges from its shape and structure is a critical question across modern science. Topological data analysis provides a powerful computational window on this problem. I will present some recent work in which we develop a framework to analyse the behaviour of complex systems via their structures. The proposed method is based on an interpretation of persistent homology summaries with network theoretical tools, combined with statistical and computational techniques.
• [02964] Spectral theory of graphs and hypergraphs
  • Format : Online Talk on Zoom
  • Author(s) :
    • Raffaella Mulas (Vrije Universiteit Amsterdam)
  • Abstract : Spectral graph theory studies the qualitative properties of a graph that can be inferred from the eigenvalues and the eigenvectors of an operator associated with it. It has a long history, and it is widely used in applications. In this talk, we recall the key properties of the graph normalized Laplacian and we generalize it to the case of hypergraphs.
• [02989] Role analysis for higher-order social systems
  • Format : Talk at Waseda University
  • Author(s) :
    • Nina Otter (Queen Mary University of London)
  • Abstract : Social scientists have been using networks to model social systems since at least the 1970s. A social network model is typically a collection of simple graphs, which can be thought of as a multi-relational graph. Studying the roles of actors in the network amounts to studying the semigroup structure of compound relations that arise from the multi-relational graph. These graph models assume a pairwise interaction between social actors. We study ways to extend the analysis of social roles to models that take into account not only pairwise but also higher-order relationships between social actors, such as social simplicial complexes and hypergraphs. A challenge in this process is to define compound higher-order relations with desirable algebraic and topological properties. In this talk I will discuss several ways to address this problem, drawing inspiration from various areas to find an appropriate generalization of composition, including q-analysis, PROPs, and chemical hypergraphs. I will then illustrate how different composition operations capture different types of information in real-world social systems. The talk is based on joint work in progress, started at the AMS MRC 2022 on Applied Category Theory, jointly with Daniel Cicala, Rachel Hardeman Morrill, Abigail Hickok, Elise McMahon, Nikola Milicevic, Nima Motamed, Emily Roff.
• [02951] Topological Information Retrieval with Dilation-Invariant Bottleneck Comparative Measures
  • Format : Online Talk on Zoom
  • Author(s) :
    • Anthea Monod (Imperial College London)
    • Yueqi Cao (Imperial College London)
    • Athanasios Vlontzos (Advanced Causal Inference (ACI) Lab )
    • Luca Schmidtke (Imperial College London)
    • Bernhard Kainz (Imperial College London)
  • Abstract : Representing elements in a database so that queries may be accurately matched is a central task in information retrieval. This is achieved by embedding the graph of the database into a manifold using a variety of metrics. Persistent homology is able to characterize a database in terms of hierarchy and connectivity. We show that embeddings retaining the database topology coincide topologically with dilation-invariant comparisons, which we propose to address metric distortion on manifolds.

contributed talk: CT079

room : E501

[02011] Network models with truncated Poisson-Dirichlet process priors

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E501
• Type : Contributed Talk
• Abstract : We introduce a Bayesian nonparametric network model based on the truncated Poisson-Dirichlet process prior. In our model, the sociability parameters of the nodes are sorted in descending order. This enables us to focus on the most popular nodes of the network. We will show the simulation algorithm and posterior inference method for this model. Numerical implementations will also be discussed based on simulated observations and real-world datasets.
• Classification : 62G05, 62F15, 60G51
• Format : Talk at Waseda University
• Author(s) :
  • Junyi Zhang (The Hong Kong Polytechnic University)
  • Angelos Dassios (London School of Economics)

[00560] Semiparametric Kernel Estimation with Bayesian Bandwidths for Multivariate Nonnegative Data

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E501
• Type : Contributed Talk
• Abstract : We introduce a flexible semiparametric kernel method for smoothing distributions on nonnegative supports. This multivariate estimator is guided by a given parametric part, here an uncorrelated exponential distribution estimated by maximum likelihood, and a nonparametric part which is a weight function to be smoothed through multiple gamma kernels. Also, a diagnostic model discusses the choice between the parametric, semiparametric and nonparametric approaches. Finally, practical multivariate semicontinuous datasets illustrate the usefulness of the method.
• Classification : 62Gxx, 62Hxx
• Format : Talk at Waseda University
• Author(s) :
  • Sobom Matthieu Somé (Université Thomas SANKARA)
  • Célestin C. Kokonendji (Université Bourgogne Franche-Comté)

[02191] Analysis Seismic Data in Sumatra Using Robust Sparse K-Means Clustering

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E501
• Type : Contributed Talk
• Abstract : K-means algorithm is considered to be the most important unsupervised machine learning method in clustering. It works intimately on complete and clear data but cannot handle outliers. Therefore, robust statistical algorithms are required to deal with it. This paper presents robust sparse k-means algorithm to show clustering of seismic data in Sumatra. Clustering results are displayed graphically for two, three and four clusters to see the zones formed based on the grouping results.
• Classification : 62-11, 62-08
• Format : Talk at Waseda University
• Author(s) :
  • Ulfasari Rafflesia (Univestitas Gadjah Mada, Yogyakarta)
  • Dedi Rosadi (Univestitas Gadjah Mada, Yogyakarta)
  • Devni Prima Sari (Universitas Negeri Padang)

[01056] Statistical methodology for functional meta-analysis of sex-based disparities in neurological diseases

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E501
• Type : Industrial Contributed Talk
• Abstract : Sex-based differences in diverse health scenarios and diseases have been acknowledged for many years but still not thorough-fully analysed. We propose a statistical methodology combining transcriptomics data from different spurces which allows to unveil those disparities at the level of differentially expressed genes and differentially enriched functions. The methodology uses linear models, meta-analysing the results through the logFC, and has been successfully applied to various diseases such as Multiple Sclerosis, Alzheimer’s and Parkinson’s diseases.
• Classification : 62-xx, 62Pxx, 92-04, 92-08, 92-10
• Format : Talk at Waseda University
• Author(s) :
  • Marta R. Hidalgo (CIPF)
  • Francisco Garcia-Garcia (CIPF)
  • Borja Gomez-Cabañes (CIPF)
  • Carla Perpiña-Clerigues (CIPF)
  • Irene Soler-Saez (CIPF)
  • Fernando Gordillo-González (CIPF)
  • Gonzalo Anton-Bernat (Universitat de València)
  • Adolfo López-Cerdan (BioBam )
  • Rubén Grillo-Risco (CIPF)
  • Jose Francisco Català-Senent (INCLIVA)

MS [00580] Mathematical Challenges in Current and Future Location Estimation Systems

room : E502

• [01325] Local Strong Convexity of Source Localization and Error Bound for Target Tracking under Time-of-Arrival Measurements
  • Format : Talk at Waseda University
  • Author(s) :
    • Anthony Man-Cho So (The Chinese University of Hong Kong)
    • Yuen-Man Pun (The Australian National University)
  • Abstract : We consider a time-varying optimization approach to the problem of tracking a moving target using noisy time-of-arrival {TOA} measurements. To analyze the tracking performance of online gradient descent {OGD}, we first revisit the classic least-squares formulation of the {static} TOA-based source localization problem and elucidate its estimation and geometric properties. Then, we show that the loss function in the formulation, albeit non-convex in general, is locally strongly convex at its global minima. To the best of our knowledge, these results are new and can be of independent interest. By combining them with existing techniques from online strongly convex optimization, we then establish the first non-trivial bound on the cumulative target tracking error of OGD.
• [01604] Machine learning techniques for resolving GNSS integer ambiguities
  • Format : Talk at Waseda University
  • Author(s) :
    • Xiao-Wen Chang (McGill University)
    • Qincheng Lu (McGill University)
  • Abstract : A key computational component in high precision GNSS positioning is to resolve carrier phase ambiguities as integers. The optimal method is to solve an integer least squares problem. Since the integer least squares problem is NP-hard, efficiency of traditional algorithms becomes problematic when the dimension of the integer ambiguity vector becomes large. To meet the challenge, we propose some machine learning based algorithms. Numerical results will demonstrate their effectiveness and efficiency.
• [01656] Fast and almost unbiased position estimation for location service
  • Format : Talk at Waseda University
  • Author(s) :
    • Peiliang Xu (Kyoto University)
  • Abstract : We propose a bias-corrected weighted LS method for precise location service, which consists of two basic elements: one to automatically correct the bias due to model nonlinearity and the induced biases in squared ranges/pseudoranges and the other to sequentially estimate unknown location parameters by treating equality constraints as a condition adjustment. The method is applied to ranges, squared ranges and the differences of squared rangesand further to pseudoranges, squared pseudoranges and the differences of pseudoranges.
• [01296] Robust Location Estimation in Wildlife Tracking Systems
  • Format : Talk at Waseda University
  • Author(s) :
    • Sivan Toledo (Tel Aviv University)
    • Eitam Arnon (Tel Aviv University)
    • Shlomo Cain (Tel Aviv University)
    • Assaf Uzan (Tel Aviv University)
    • Ran Nathan (Hebrew University of Jerusalem)
    • Orr Spiegel (Tel Aviv University)
  • Abstract : The talk will describe new location-estimation algorithms for time-of-arrival transmitter localization systems. The new algorithms use the consensus principle and they detect and discard outlier time-of-arrival observations, which can be caused by non-line-of-sight propagation, radio interference, clock glitches, or an overestimation of the signal-to-noise ratio. They also detect cases in which two locations are equally consistent with the measurements and can usually select the correct one based on unambiguous estimates shortly before or after.

contributed talk: CT081

room : E503

[01125] Generalized Optimization Algorithms for $M$-Estimation of Complex Simulation Models

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E503
• Type : Contributed Talk
• Abstract : We provide a new optimization algorithm for simulation-based models with highly irregular objective functions, like those of network or agent-based models. The approximate inexact Newton method (AINM) is based on approximating the first two derivatives of the function through a polynomial regression. We provide new general results concerning approximate Netwon methods, we extensively discuss the theoretical and computational aspects of the AINM, and support the theory by Monte Carlo experiments and two applications.
• Classification : 90Cxx, 62F10, 62J05
• Format : Talk at Waseda University
• Author(s) :
  • Raffaello Seri (Università degli Studi dell'Insubria)
  • Mario Martinoli (Scuola Superiore Sant'Anna Pisa)
  • Fulvio Corsi (Università di Pisa)

[02249] An Adaptive Time Stepping Scheme for Rate-Independent Systems

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E503
• Type : Contributed Talk
• Abstract : We investigate a local incremental stationary scheme for the numerical solution of rate-independent systems. The main novelty of our approach in comparison to existing methods is an adaptive choice of the step size for the update of the curve parameter. It is proven that the piecewise affine approximations generated by the algorithm converge (weakly) to a so-called parametrized balanced viscosity solution. Numerical experiments illustrate the theoretical findings and show a significant increase of the step size during sticking and in viscous jumps.
• Classification : 65J08, 65K15, 65M12, 65M50
• Format : Talk at Waseda University
• Author(s) :
  • Merlin Andreia (TU Dortmund University)
  • Christian Meyer (TU Dortmund University)

[02032] Stable Minimization of Discrete Conformal Energy for Disk Conformal Parameterization

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E503
• Type : Contributed Talk
• Abstract : Conformal energy minimization is an efficient approach to computing conformal parameterizations. In this talk, we introduce a stable minimization of discrete conformal energy (SMDCE) algorithm for conformal parameterizations of simply connected open surface. The stability of SMDCE is reflected in the guarantee of the one-to-one and onto properties of the computed parameterization and the insensitivity to the initial value. The numerical experiments indicate the stability and competitiveness with state-of-the-art algorithms in terms of efficiency.
• Classification : 52C26, 49Q10, 68U05
• Format : Talk at Waseda University
• Author(s) :
  • Zhong-Heng Tan (School of Mathematics, Southeast University)
  • Zhenyue Zhang (Nanjing Center for Applied Mathematics)

[02549] Copula for Markov Chain Model with Binomial Time Series Data

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E503
• Type : Contributed Talk
• Abstract : Markov Chain Model can be constructed by the concept of time dependency and approached by the Copula. Markov Chain Model using Clayton and Joe Copula is proposed to determine the 3-sigma control limit in statistical control process for time series binomial data. In this paper, Gumbel and Frank Copula use in determining the 3-sigma control limits. We conduct simulations to see the performance of the developed methods and analyze the number of defective pieces in the jewelry manufacturing process.
• Classification : 62-08, 62A99
• Author(s) :
  • Pepi Novianti (Universitas Gadjah Mada, University of Bengkulu)
  • Gunardi Gunardi (Universitas Gadjah Mada)
  • Dedi Rosadi (Universitas Gadjah Mada)

[01153] Analysis of driver’s behavior and average flow on traffic dynamics

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E503
• Type : Contributed Talk
• Abstract : In this work, a new lattice model is proposed by considering the driver’s behavior (timid or aggressive) and downstream average flow on traffic dynamics. The stability condition is determined through stability analysis. Nonlinear analysis forms the modified Korteweg-de Vries (mKdV) equation to describe traffic density wave propagation near the critical point. Theoretical results are verified with numerical simulations, and it is concluded that driver behavior and average flow can stabilize traffic flow dynamics.
• Classification : 65P40, 65K05, Traffic flow
• Author(s) :
  • Nikita Madaan (Chandigarh University)
  • Nikita Madaan (Thapar Institute of Engineering and Technology)
  • Sonia - (Chandigarh University)

contributed talk: CT085

room : E504

[00098] Robust bring your own encryption algorithm using generalized heat equation associated with generalized Vigen$\grave{e}$re-type table over symmetric group

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E504
• Type : Contributed Talk
• Abstract : We develop a secure bring your own encryption algorithm that encrypts personal data. The proposed algorithm is based on a generalized heat equation associated with a generalized Vigen$\grave{e}$re-type table over symmetric group $S_{n}$ so that existing attacks will be infeasible. Encryption keys are obtained from random key sequences tested by NIST statistical test suite. The robustness of the proposed algorithm has been found by comparing it with other competing existing algorithms.
• Classification : 68P25, 68P30, Image encryption.
• Format : Talk at Waseda University
• Author(s) :
  • Manish Kumar (BITS Pilani, Hyderabad Campus, Telangana, India)

[00805] A Topological Model of Textile Structures

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E504
• Type : Contributed Talk
• Abstract : Textiles are complex entangled structures made of threads embedded in a thickened plane. From nano to macro scale and high functionality to pure esthetic, they have been studied and fabricated for thousands of years in disciplines as diverse as materials science and art. Currently an active research topic in mathematics, we will present a topological model that aims to define, construct and classify specific textile structures from a knot theory viewpoint and highlight some applications.
• Classification : 57K10, 57K12
• Format : Talk at Waseda University
• Author(s) :
  • Sonia Mahmoudi (Drexel University)

[01452] Some Statistical Properties and Maximum Likelihood Estimation of Parameters of Bivariate Modified Weibull Distribution with its Real-Life Applications

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E504
• Type : Contributed Talk
• Abstract : Real-life data sets with ties arise quite commonly in medicine, industry, reliability and survival analysis. We attempt to model such types of data sets using bivariate distributions with singular components. For this purpose, we consider mainly two types of approaches, namely the "Minimization approach" and the "Maximization approach." Using the minimization approach the bivariate modified Weibull (BMW) distribution is derived. Due to five parameters, the BMW is a more general and flexible distribution. It reduces to the Marshall-Olkin bivariate exponential (MOBE) and Marshall-Olkin bivariate Weibull (MOBW) distributions under certain parameter restrictions. Some distributional, modal and aging properties of BMW will be discussed. The copula associated with BMW distribution is given. Finally, we will discuss the maximum likelihood estimation of parameters of BMW distribution via the EM algorithm. We will give some numerical results of a real-life data set with ties.
• Classification : 62Nxx, Mainly to developed models to analyze real life bivariate data sets where the ties occur naturally in the data sets. The data may be censored . Such type of models are known as Bivariate distributions with singular component.
• Format : Talk at Waseda University
• Author(s) :
  • Sanjay Kumar (Ph.D. Student, Department of Mathematics & Statistics, Indian Institute of Technology Kanpur)
  • Debasis Kundu (Professor, Department of Mathematics & Statistics, Indian Institute of Technology Kanpur)
  • Sharmishtha Mitra (Professor, Department of Mathematics & Statistics, Indian Institute of Technology Kanpur)

[02420] Nonparametric Bivariate Density Estimation for Missing Censored Lifetimes

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E504
• Type : Contributed Talk
• Abstract : Estimation of the joint density of two censored lifetimes is a classical problem in survival analysis, but only recently the theory and methodology of efficient nonparametric estimation have been developed. A familiar complication in survival analysis is that in real data censored lifetimes and indicators of censoring may be missing. For the model of missing completely at random, an efficient bivariate density estimator is proposed, and a practical example is presented.
• Classification : 62N02, 62G05, 62G07, Missing data, survival analysis and censoring, nonparametric estimation
• Format : Online Talk on Zoom
• Author(s) :
  • Lirit Fuksman (The University of Texas at Dallas)

[00853] Numerical Approximation of Fractional Burgers Equation with Non-singular Time-Derivatives

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E504
• Type : Contributed Talk
• Abstract : Fractional Burgers equation (FBE) is a partial differential equation being non-linear in space. This work presents a numerical method to solve a time-FBE with second order of convergence. The fractional time-derivative is taken as non-singular derivative whose kernel contains the Mittag-Leffler function. The discretization of derivatives is done by using finite difference method and Newton iteration method. Developed numerical scheme is stable and convergent in L^∞ norm. Examples have been illustrated to validate the theory.
• Classification : 26A33, 65R10, 35R11
• Format : Online Talk on Zoom
• Author(s) :
  • Swati Yadav (NTNU Trondheim)
  • Swati Yadav (NTNU Trondheim)
  • Rajesh Kumar Pandey (IIT BHU, Varanasi)

contributed talk: CT087

room : E505

[01068] Reverse engineering controller area network using the Pearson correlation coefficient

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E505
• Type : Industrial Contributed Talk
• Abstract : Controller Area Network \(CAN\) is a communication bus widely adopted in road vehicles. However, car manufacturers adopt proprietary CAN message sets, complicating message decoding by third-party applications, e.g., for indirectly detecting adverse road-weather conditions. This talk presents an algorithm for reverse engineering CAN messages based on the Pearson correlation coefficient between CAN messages from an annotated and interpolated dataset. The proposed algorithm was experimentally validated with data collected from different vehicle brands.
• Classification : 62P30, 68P20, 62-04
• Format : Talk at Waseda University
• Author(s) :
  • David Rocha (Instituto de Telecomunicacoes, Universidade de Aveiro)
  • João Almeida (Instituto de Telecomunicações, Universidade de Aveiro)
  • José Fonseca (Instituto de Telecomunicações, Universidade de Aveiro)
  • Joaquim Ferreira (Instituto de Telecomunicações, Universidade de Aveiro)

[02487] Asset Forecasting Using Geometric Brownian Motion and Variance Gamma Models

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E505
• Type : Contributed Talk
• Abstract : The basic assumption in the Black-Scholes-Merton model is log returns assets normally distributed. In reality, asset price movements are so fluctuating that the data is not normally distributed. This paper proposes a way to forecast using the variance gamma (VG) model. The VG model has three parameters to control volatility, skewness, and kurtosis. We compare results with the geometric Brownian motion (GBM) model. The accuracy of the model used the mean absolute percentage error (MAPE).
• Classification : 62P20
• Format : Online Talk on Zoom
• Author(s) :
  • Abdul Hoyyi (Gadjah Mada University)
  • Abdurakhman Abdurakhman (Gadjah Mada University)
  • Dedi Rosadi (Gadjah Mada University)

[02572] LDA Hyper-parameters Regulation for Qualitative Studies in Management

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E505
• Type : Contributed Talk
• Abstract : The suitability of the number of topics in management qualitative research is a complex problem. Topic models on textual data often require judgment expertise in determining suitability for management problems. One of the things to note is the determination of hyperparameter values. We have designed various hyper-parameter value conditions as an experiment and calculated the document match probability based on the topic grouping results. Different hyperparameter values indicate different levels of probability.
• Classification : 62P25, 68W99, 91C20
• Format : Online Talk on Zoom
• Author(s) :
  • Evita Purnaningrum (Mathematics Department, Gadjah Mada University)
  • Abdurakhman Abdurakhman (Mathematics Department, Gadjah Mada University)
  • Nanang Susyanto (Mathematics Department, Gadjah Mada University)

[00129] Anomalous diffusion in standard maps with extensive chaotic phase spaces

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E505
• Type : Contributed Talk
• Abstract : In this work, we investigate the long-term diffusion transport and chaos properties of single and coupled standard maps (SMs). We analyze parameters that are known to produce anomalous diffusion in the phase spaces of maps, with the presence of so-called accelerator modes. We study how different ensembles affect the behavior, asymptotic diffusion rates, and time scales required for these maps. We also explore the global diffusion properties and chaotic dynamics of various coupled SM configurations.
• Classification : 65Pxx
• Format : Talk at Waseda University
• Author(s) :
  • Henok Tenaw Moges (University of Cape Town)
  • Henok Tenaw Moges (University of Cape Town)
  • Charalampos Skokos (University of Cape Town)

[02022] Use of jet transport for high order methods

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E505
• Type : Contributed Talk
• Abstract : The use of multivariate polynomial, called jet, in conjunction with numerical solvers, called transport, has recently become a new baseline to address computations based on high order methods. Jet transport provides more accurate, efficient, and reliable results through automatizing several crucial parts. In this talk, I will explain these most recent results and supported by examples in areas in dynamical systems.
• Classification : 65Pxx, 37Mxx, 37M21, Numerical integrators for dynamical systems
• Format : Online Talk on Zoom
• Author(s) :
  • Joan Gimeno (University of Barcelona)
  • Angel Jorba (University of Barcelona)
  • Marc Jorba (Centre de Recerca Matemàtica)
  • Narcís Miguel (PAL Robotics S.L.)
  • Maorong Zou (University of Texas at Austin)

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

room : E506

• [04645] Using Low-rank Tensor Formats in Neural Networks
  • Format : Talk at Waseda University
  • Author(s) :
    • Thong Pham Hoang Le (RWTH Aachen University)
    • Lars Grasedyck (RWTH Aachen)
    • Janina Enrica Schütte (WIAS Berlin)
    • Martin Eigel (WIAS Berlin)
  • Abstract : We investigate the use of low-rank tensor decompositions to improve the performance of neural network training. Specifically, we propose an approach that utilizes low-rank tensors to discretize the loss function of the neural network, which allows us to explore a larger parameter space than local methods such as Gradient Descent. Our approach could also facilitate improved weight initialization, further enhancing the network's performance.
• [03998] Adaptive Multilevel Neural Networks for parametric PDEs with Error Estimation
  • Format : Talk at Waseda University
  • Author(s) :
    • Janina Enrica Schütte (WIAS Berlin)
    • Martin Eigel (WIAS)
  • Abstract : We focus on efficiently solving high dimensional, parameter-dependent partial differential equations. To approximate the parameter-to-solution map, different model classes have been considered, including low-rank tensor representations and neural network architectures. In our work, a new multilevel neural network architecture is combined with an adaptive scheme including a solver based on a multilevel decomposition, classical reliable finite element error estimators, and a refinement strategy for the considered finite element grids. We show expressivity results and numerical experiments for the derived networks.

MS [00917] High-dimensional regression and sampling

room : E507

• [05533] On minimizing the training set fill distance in regression
  • Format : Talk at Waseda University
  • Author(s) :
    • Paolo Climaco (Universität Bonn)
    • Jochen Garcke (Universität Bonn & Fraunhofer SCAI)
  • Abstract : Machine learning regression methods leverage large datasets for training predictive models.However, using large datasets may not be feasible due to computational limitations or high labelling costs. Therefore, sampling small training sets from large pools of unlabelled data is essential to maximize performance while maintaining computational efficiency. In this work, we study a sampling approach aimed to minimize the fill distance of the selected set. We derive an upper bound for the maximum expected prediction error that linearly depends on the training set fill distance, conditional to the knowledge of data features. For empirical validation, we show that selecting a training by farthest point sampling significantly reduces the maximum prediction error, outperforming existing sampling approaches.
• [05514] Efficient training of Gaussian processes with tensor product structure
  • Format : Talk at Waseda University
  • Author(s) :
    • Max Pfeffer (University of Goettingen)
    • Josie König (Universität Potsdam)
    • Martin Stoll (TU Chemnitz)
  • Abstract : We consider the special case of Gaussian process kernel learning where the covariance function is given by a sum of products of RBF kernels. For a given dataset, the parameters of the kernel are learned by minimizing the log marginal likelihood. Computing the log-determinant of the covariance matrix is prohibitive for large datasets or in high dimensions unless one exploits its low-rank tensor structure. We employ a stochastic trace estimation together with a Lanczos algorithm for TT-tensors (Tensor Trains). This allows us to break the curse of dimensionality and to perform a gradient-based optimization even in high dimensions.
• [05610] Tensor decompositions for high-dimensional kernel regression
  • Author(s) :
    • Frederiek Wesel (Delft University of Technology)
    • Kim Batselier (Delft University of Technology)
  • Abstract : Kernel machines provide a nonlinear extension to linear methods by projecting the data in a higher-dimensional feature space. When considering product kernels, the dimensionality of the feature space grows exponentially with the dimensionality of the data, limiting these methods to small-dimensional data. We lift this limitation by constraining the model weights to be a canonical polyadic decomposition of low rank. This allows us to derive a block coordinate descent algorithm which allows for the training of kernel machines under such constraint at a computational complexity which is linear both in the number of samples and in the dimensionality of the data, allowing to tackle both large-sampled and high-dimensional data.
• [05481] Optimal sampling for regression: from linear to nonlinear approximation
  • Format : Online Talk on Zoom
  • Author(s) :
    • Anthony Nouy (Nantes Université - Centrale Nantes)
  • Abstract : We consider the approximation of functions in L^2 from point evaluations, using linear or nonlinear approximation tools. For linear approximation, recent results show that weighted least-squares projections allow to obtain quasi-optimal approximations with near to optimal sampling budget. This can be achieved by drawing i.i.d. samples from suitable distributions (depending on the linear approximation tool) and subsampling methods. In a first part of this talk, we review different strategies based on i.i.d. sampling and present alternative strategies based on repulsive point processes that allow to achieve the same task with a reduced sampling complexity. In a second part, we show how these methods can be used to approximate functions with nonlinear approximation tools, in an active learning setting, by coupling iterative algorithms and optimal sampling methods for the projection onto successive linear spaces. We particularly focus on the approximation using tree tensor networks, whose architectures allow for an efficient implementation of optimal sampling procedures within coordinate descent algorithms. These are joint works with R. Gruhlke, B. Michel, C. Miranda and P. Trunschke

MS [02327] Stability of Numerical Linear Algebra Algorithms

room : E508

• [02923] A projection method for singular eigenvalue problems of linear matrix pencils
  • Format : Talk at Waseda University
  • Author(s) :
    • Keiichi Morikuni (University of Tsukuba)
    • Akira Imakura (University of Tsukuba)
  • Abstract : Complex moments consisting of matrix resolvents filter out undesired eigencomponents and extract the desired ones from a pseudo-random matrix. This study extends a projection method using complex moments for regular eigenproblems to the singular nonsquare case. We establish conditions such that the method gives all finite eigenvalues in a prescribed region in the complex plane and the corresponding eigenvectors. Numerical experiments show that the new method is more robust and efficient than previous methods.
• [03257] Backward stability in rational eigenvalue problems solved via linearization
  • Format : Talk at Waseda University
  • Author(s) :
    • Froilán Martínez Dopico (Universidad Carlos III de Madrid)
    • María del Carmen Quintana (Aalto University )
    • Paul Van Dooren (Université catholique de Louvain)
  • Abstract : The numerical solution of nonlinear eigenvalue problems has attracted a lot of attention from the Numerical Linear Algebra community in the last twenty years. Among these problems, rational eigenvalue problems are particularly relevant because they appear directly in many applications and because they are often used to approximate other more general nonlinear eigenvalue problems. One of the most reliable methods for solving numerically rational eigenvalue problems is via linearizations. In this talk we present recent results on the backward stability of this approach.
• [03008] Computing the matrix sign function with the double exponential formula
  • Format : Talk at Waseda University
  • Author(s) :
    • Tomoya Miyashita (The University of Electro-Communications)
    • Shuhei Kudo (The University of Electro-Communications)
    • Yusaku Yamamoto (The University of Electro-Communications)
  • Abstract : Matrix sign function plays an important role in many scientific computations. There are various methods for computing the matrix sign function, such as Newton’s method, the Schur method, and methods based on integral representation. Among them, the integral-based methods are suitable for parallelization because the calculation at each sample point is independent. In this talk, we focus on the integral-based method using the double exponential (DE) formula recently proposed by Nakaya and Tanaka and evaluate its numerical accuracy and parallel performance on the Fugaku computer. We also show a new theoretical upper bound on its discretization and truncation errors.

contributed talk: CT096

room : E603

[01052] Large systems of linear equations in particle transport problems

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E603
• Type : Contributed Talk
• Abstract : This work discusses solutions of large linear systems of algebraic equations relevant to establish a solution to the discrete ordinates approximation of the two-dimensional linear Boltzmann equation. Direct and iterative methods are investigated, along with domain decomposition techniques and parallel implementation. The type of the quadrature scheme describing the directions and the class of problems to be solved, neutron or radiation problems, directly affect the final choice of the numerical algorithm.
• Classification : 65F22, 65F05, 65F10, 65MXX
• Format : Talk at Waseda University
• Author(s) :
  • Rudnei Dias da Cunha (Universidade Federal do Rio Grande do Sul)
  • Liliane Basso Barichello (Universidade Federal do Rio Grande do Sul)

[00883] Convergence of the Eberlein diagonalization method

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E603
• Type : Contributed Talk
• Abstract : The Eberlein method is a Jacobi-type process for solving the eigenvalue problem of an arbitrary matrix. In each iteration two transformations are applied on the underlying matrix, a plane rotation and a non-unitary elementary transformation. In this talk we present the method under the broad class of generalized serial pivot strategies. We provide the proof of the global convergence and give several numerical examples.
• Classification : 65F15
• Format : Talk at Waseda University
• Author(s) :
  • Erna Begovic (University of Zagreb)
  • Ana Perkovic (University of Zagreb)

[01254] Fast SVD-Preconditioned Eigensolver for 3D Phononic Crystals

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E603
• Type : Contributed Talk
• Abstract : In this talk, a Fast Linear Elastic Eigenvalue Problem Solver (FLEEPS) is developed to calculate band structures of 3D isotropic phononic crystals. FLEEPS is an iterative eigensolver of quasi-linear complexity to compute the smallest few eigenvalues of the linear elastic eigenvalue problem. The weighted SVD-preconditioned CG method in FLEEPS convergences faster than the AMG-preconditioned CG method by more than 60 times. Band structure calculations of several 3D isotropic phononic crystals demonstrate the strengths of FLEEPS.
• Classification : 65F15, 74E10, 74E15
• Format : Talk at Waseda University
• Author(s) :
  • Tiexiang Li (Southeast University)
  • Heng Tian (Sichuan University of Science and Engineering)
  • Xing-Long Lyu (Southeast University)
  • Wen-Wei Lin (National Yang Ming Chiao Tung University)

[01371] A mixed element scheme of Helmholtz transmission eigenvalue problem for anisotropic media

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E603
• Type : Contributed Talk
• Abstract : In this paper, we study the Helmholtz transmission eigenvalue problem for inhomogeneous anisotropic media in two and three dimension. Starting with a nonlinear fourth order formulation established by Cakoni, Colton and Haddar in 2009, by introducing some auxiliary variables, we present an equivalent mixed formulation for this problem, followed up with the finite element discretization. Using the proposed scheme, we rigorously show that the optimal convergence rate for the transmission eigenvalues both on convex and nonconvex domains can be expected. Moreover, by this scheme, we will obtain a sparse generalized eigenvalue problem whose size is so demanding even with a coarse mesh that its smallest few real eigenvalues fail to be solved by the shift and invert method. We partially overcome this critical issue by deflating the almost all of the ∞ eigenvalue of huge multiplicity, resulting in a drastic reduction of the matrix size without deteriorating the sparsity. Extensive numerical examples are reported to demonstrate the effectiveness and efficiency of the proposed scheme.
• Classification : 65F15, 65M60, 65N25, 78M10
• Format : Talk at Waseda University
• Author(s) :
  • Qing Liu (School of Mathematics, Southeast University)
  • Tiexiang Li (School of Mathematics, Southeast University)
  • Shuo Zhang (Academy of Mathematics and System Sciences, Chinese Academy of Sciences)

[01588] Stable numerical schemes and adaptive algorithms for fractional diffusion-wave equation

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E603
• Type : Contributed Talk
• Abstract : This work develops a stable scheme and adaptive algorithm for time-fractional mathematical models. Developed algorithm allows one to build adaptive nature where numerical scheme is adjusted according to behavior of $\alpha$ to keep errors very small and converge to solution very fast. Analysis of numerical scheme has been established thoroughly. Moreover, a reduced order technique is implemented by using moving mesh refinement to improve accuracy at several time levels.
• Classification : 65N06, 65N50, 65N12, 65N15
• Author(s) :
  • Vineet Kumar Singh (Indian Institute of Technology (BHU), Varanasi, India)
  • Rahul Kumar Maurya (Government Tilak P.G. College, Katni, Madhya Pradesh, India)

contributed talk: CT104

room : E604

[02248] Remedies for entropy growth from iterative methods in CFD

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E604
• Type : Contributed Talk
• Abstract : We explore the influence of iterative methods on entropy-conserving and dissipative discretizations of nonlinear conservation laws with implicit time discretizations. Newton's method can cause entropy dissipative schemes to become anti-dissipative, even with smaller iteration errors than time integration errors. We suggest various remedies and find a relaxation technique to be the most effective. Numerical experiments with dispersive wave equations demonstrate that entropy conservation produces more accurate results than non-conservative schemes, even with larger tolerances.
• Classification : 65M12, 65N22, 65H10, 65F10
• Format : Talk at Waseda University
• Author(s) :
  • Viktor Linders (Lund University)
  • Philipp Birken (Lund University)

[02568] A pressure-stabilized projection Lagrange--Galerkin scheme for the transient Oseen problem

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E604
• Type : Contributed Talk
• Abstract : We propose and analyze a pressure-stabilized projection Lagrange--Galerkin scheme for the transient Oseen problem. The proposed scheme inherits the advantages from the projection Lagrange--Galerkin scheme: computational efficiency and essential unconditional stability. Here we also use the equal-order approximation for the velocity and pressure, and add a symmetric pressure stabilization term. This enriched pressure space enables us to obtain accurate solutions for small viscosity.
• Classification : 65M12, 65M25, 65M60, 76D07, 76M10
• Format : Talk at Waseda University
• Author(s) :
  • Shinya Uchiumi (Gakushuin University)

[01986] Low regularity time integration of NLS via discrete Bourgain spaces

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E604
• Type : Contributed Talk
• Abstract : We study a filtered Lie splitting scheme for the cubic periodic nonlinear Schrödinger equation on the torus $\mathbb{T}^d$ with $d\geq1$. This scheme overcomes the standard stability restriction $s>\frac d2$ in Sobolev spaces $H^s(\mathbb{T}^d)$ and now allows us to handle initial data in $H^s$ for $s>0$ when $d=1,2$ and $s>\frac d2-1$ when $d\geq3$. Moreover, we establish low regularity error estimates in discrete Bourgain spaces, and prove convergence of order $\tau^{\frac s2}$ in $L^2(\mathbb{T}^d)$, where $\tau$ denotes the time step size.
• Classification : 65M12, 65M15, 35Q55
• Format : Talk at Waseda University
• Author(s) :
  • Lun Ji (Universität Innsbruck)
  • Alexander Ostermann (Universität Innsbruck)
  • Frédéric Rousset (Université Paris-Saclay)
  • Katharina Schratz (Sorbonne Université)

[02608] Explorative computing for stable and consistent kinetic relaxation in lattice Boltzmann methods

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E604
• Type : Contributed Talk
• Abstract : Using lattice Boltzmann methods with multiple relaxation times for robust and fast incompressible turbulent flow simulations requires tuning of the kinetic parameters. We outsource the perfect parallelizability of lattice Boltzmann methods to analyze kinetic relaxation with respect to non-linear stability and consistency based on explorative computing of artificial turbulence in three dimensions. Conclusively, numerical indication is provided, that accuracy and dissipation is adaptively balanced near the Bhatnagar–Gross–Krook single relaxation time approximated in the scale-resolving limit.
• Classification : 65M12, 35Q20, 35Q30, 76D05
• Format : Talk at Waseda University
• Author(s) :
  • Stephan Simonis (Karlsruhe Institute of Technology)
  • Mathias J. Krause (Karlsruhe Institute of Technology)

[02337] Numerical analysis for the cancer invasion system with nonlocal diffusion

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E604
• Type : Contributed Talk
• Abstract : Cancer modelling is challenging in grounds of capturing the physics behind it and performing numerical simulations. In this work, we analyze the cancer invasion model with nonlocal diffusion. First, the Galerkin finite element scheme is implemented to the given system of equations for spatial discretization. Then, backward Euler scheme is applied for temporal discretization. Further, a priori error bounds and convergence estimates for the fully-discrete problem are derived. Numerical tests provided validate the theoretical studies.
• Classification : 65M15, 65M60, 92B05
• Format : Talk at Waseda University
• Author(s) :
  • Kausika Chellamuthu (Bharathiar University, Coimbatore 641046, Tamil Nadu.)
  • Manimaran Jeyaraj (Vellore Institute of Technology)
  • Manimaran Jeyaraj (Vellore Institute of Technology, Chennai Campus, Chennai - 600127.)

MS [01064] Recent Advances on Manifold Optimization

room : E605

• [03743] Design of Tight Minimum-Sidelobe Windows via Optimization on Oblique Manifolds
  • Format : Online Talk on Zoom
  • Author(s) :
    • Daichi Kitahara (Osaka University)
    • Kohei Yatabe (Tokyo University of Agriculture and Technology)
  • Abstract : The short-time Fourier transform (STFT), or the discrete Gabor transform (DGT), has been widely utilized in signal analysis and processing. For noise-robust STFT/DGT domain signal processing, windows used in STFT/DGT are desired to be tight. In this talk, we propose to design tight windows minimizing the sidelobe energy. It is expressed as the maximization of Rayleigh quotients on oblique manifolds. We apply the Riemannian Newton's method to obtain the optimal tight windows by several iterations.
• [04008] The Bures-Wasserstein geometry of the manifold of fixed-rank positive-semidefinite matrices
  • Format : Online Talk on Zoom
  • Author(s) :
    • Estelle Massart (UCLouvain)
    • Pierre-Antoine Absil (UCLouvain)
  • Abstract : We explore the well-known identification of the manifold of rank p positive-semidefinite matrices of size n with the quotient of the set of full-rank n-by-p matrices by the orthogonal group in dimension p. The induced metric corresponds to the Wasserstein metric between centered degenerate Gaussian distributions, and is a generalization of the Bures–Wasserstein metric on the manifold of positive-definite matrices.
• [02861] Cayley parametrization strategy for optimization over the Stiefel manifold
  • Format : Talk at Waseda University
  • Author(s) :
    • Keita Kume (Tokyo Institute of Technology)
    • Isao Yamada (Tokyo Institute of Technology)
  • Abstract : We introduce the basic idea behind the adaptive localized Cayley parametrization strategy for optimization over the Stiefel manifold. The proposed adaptive strategy can mitigate slow convergence caused by singular-points of the naive Cayley parametrization. Unlike the so-called retraction-based strategy, the proposed strategy can utilize directly many powerful Euclidean optimization algorithms. For a certain class of optimization algorithms combined with the proposed parametrization strategy, we also explain briefly an idea for their unified convergence analyses.
• [02851] Accelerated gradient methods on the Grassmann and Stiefel manifolds
  • Format : Talk at Waseda University
  • Author(s) :
    • Xiaojing Zhu (Shanghai University of Electric Power)
  • Abstract : In this talk we extend a nonconvex version of Nesterov's accelerated gradient method to optimization over the Grassmann and Stiefel manifolds. We propose an exponential-based AG algorithm for the Grassmann manifold and a retraction-based AG algorithm that exploits the Cayley transform for both of the Grassmann and Stiefel manifolds. Global rates of convergence of our algorithms are analyzed under reasonable assumptions. Details of computing some geometric objects as ingredients of our algorithms are also discussed.

contributed talk: CT101

room : E606

[00858] An adaptive spectral method for oscillatory second-order linear ODEs with frequency-independent cost

• Session Time & Room : 3D (Aug.23, 15:30-17:10) @E606
• Type : Contributed Talk
• Abstract : I will introduce an efficient method for solving 2nd order, linear ODEs whose solution may vary between highly oscillatory and slowly changing over the solution interval. Within a marching scheme, the solution is generated either via a nonoscillatory phase function (computed by defect correction), or spectral collocation, whichever is more efficient for the current timestep. With numerical experiments I will show that our algorithm outperforms other state-of-the-art oscillatory solvers and has a frequency-independent runtime.
• Classification : 65Lxx, 34E05, 65L60, 34-04, 65Gxx
• Format : Talk at Waseda University
• Author(s) :
  • Fruzsina Julia Agocs (Center for Computational Mathematics, Flatiron Institute)
  • Alex Harvey Barnett (Center for Computational Mathematics, Flatiron Institute)

[01151] Structure-Preserving Neural Networks for Hamiltonian Systems

• Session Time & Room : 3D (Aug.23, 15:30-17:10) @E606
• Type : Contributed Talk
• Abstract : When solving Hamiltonian systems using numerical integrators, preserving the symplectic structure is crucial. We analyze whether the same is true if neural networks (NN) are used. In order to include the symplectic structure in the NN's topology we formulate a generalized framework for two well-known NN topologies and discover a novel topology outperforming all others. We find that symplectic NNs generalize better and give more accurate long-term predictions than physics-unaware NNs.
• Classification : 65Lxx, 68T07, 85-08
• Format : Talk at Waseda University
• Author(s) :
  • Philipp Horn (Eindhoven University of Technology)
  • Barry Koren (Eindhoven University of Technology)
  • Veronica Saz Ulibarrena (Leiden University)
  • Simon Portegies Zwart (Leiden University)

[00013] Singularly perturbed problems on a graph

• Session Time & Room : 3D (Aug.23, 15:30-17:10) @E606
• Type : Contributed Talk
• Abstract : In this talk, a singularly perturbed convection diffusion problems on a graph domain will be discussed. Initially, the problem is designed on a simple graph i.e k-star graph. On the common vertex, the continuity and the Kirchhoff's conditions will be discussed along with their complexity. The problem may be extended to a general graph with many vertices and edges. Some tests problems will be discussed based on upwind finite difference methods using piece-wise Shishkin meshes. Error estimates and the order of convergence are to be discussed.
• Classification : 65Lxx, 65Mxx
• Format : Online Talk on Zoom
• Author(s) :
  • Vivek Kumar Aggarwal (Delhi Technological University)

[00460] A Multigrid Method for Many-Electron Schrodinger Equations with ACE

• Session Time & Room : 3D (Aug.23, 15:30-17:10) @E606
• Type : Contributed Talk
• Abstract : We parameterize the many-electron wave functions by atomic cluster expansion $($ACE$)$ approach and calculate ground-state energies and electron densities of some molecule systems within the variational Monte Carlo framework. Compared with the neural-network-based representations, the novelty of our method lies in $($i$)$ a convenient and accurate linear polynomial expansion; $($ii$)$ a hierarchical structure that applies naturally to a multigrid variation; and $($iii$)$ possibly revealing the correlation of the system by increasing the body-order.
• Classification : 35Q40, 65N25, 65N35, 81Q05
• Format : Talk at Waseda University
• Author(s) :
  • Dexuan Zhou (Beijing Normal University)

[02103] Global in Time Weak Solutions to Singular 3D Quasi-Geostrophic Systems

• Session Time & Room : 3D (Aug.23, 15:30-17:10) @E606
• Type : Contributed Talk
• Abstract : Geophysicists have studied 3D Quasi-Geostrophic systems extensively. These systems describe stratified flows in the atmosphere on a large time scale and are widely used for forecasting atmospheric circulation. They couple an inviscid transport equation in $\mathbb{R}_{+}\times\Omega$ with an equation on the boundary satisfied by the trace, where $\Omega$ is either $2D$ torus or a bounded convex domain in $\mathbb{R}^2$. In this talk, we show the existence of global in time weak solutions to a family of singular 3D quasi-geostrophic systems with Ekman pumping, where the background density profile degenerates at the boundary. The proof is based on the construction of approximated models which combine the Galerkin method at the boundary and regularization processes in the bulk of the domain. The main difficulty is handling the degeneration of the background density profile at the boundary.
• Classification : 35Q35, 76D03
• Format : Online Talk on Zoom
• Author(s) :
  • Yiran Hu (University of Texas at Austin)

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

room : E701

MS [00719] Recent Advances in Numerical PDE and Scientific Machine Learning

room : E702

• [04237] Level set learning for nonlinear dimensionality reduction in function approximation
  • Format : Talk at Waseda University
  • Author(s) :
    • Zhu Wang (University of South Carolina)
  • Abstract : Approximating high-dimensional functions is challenging due to the curse of dimensionality. Inspired by the Nonlinear Level set Learning method that uses the reversible residual network, we developed a new method, Dimension Reduction via Learning Level Sets, for function approximations. It contains two major components: one is the pseudo-reversible neural network module that effectively transforms high-dimensional input variables to low-dimensional active variables, and the other is the synthesized regression module for approximating function values based on the transformed data in the low-dimensional space. Numerical experiments will be presented to demonstrate the proposed method.
• [03271] Semi-analytic PINN methods for boundary layer problems on rectangular domains
  • Format : Talk at Waseda University
  • Author(s) :
    • Chang-Yeol Jung (UNIST)
    • Gung-Min Gie (University of Louisville)
    • Youngjoon Hong (Sungkyunkwan University)
    • Tselmuun Munkhjin (UNIST)
  • Abstract : Singularly perturbed boundary value problems exhibit sharp boundary layers in their solutions, making their numerical approximation challenging due to the stiffness of these layers, resulting in significant computational errors. Traditional numerical methods require extensive mesh refinements near the boundary to obtain accurate solutions, which can be costly in terms of computation. To address these challenges, we have employed physics-informed neural networks (PINNs) to solve singularly perturbed problems. However, PINNs can struggle with rapidly varying singularly perturbed solutions over a small domain region, resulting in insufficient resolution that can lead to inaccurate results. To overcome this limitation, we consider the semi-analytic methods which enrich the PINNs with so-called corrector functions. Our numerical experiments demonstrate significant improvements in accuracy and stability.
• [04847] Solving Wave Equations with Fourier Neural Operator
  • Format : Talk at Waseda University
  • Author(s) :
    • Bian Li (Lehigh University)
    • Hanchen Wang (Los Alamos National Lab)
    • Shihang Feng (Los Alamos National Lab)
    • Xiu Yang (Lehigh University)
    • Youzuo Lin (Los Alamos National Lab)
  • Abstract : In the study of subsurface seismic imaging, solving the acoustic wave equation is a pivotal component in existing models. Inspired by the idea of operator learning, this work leverages the Fourier neural operator (FNO) to effectively learn the frequency domain seismic wavefields under the context of variable velocity models. We also propose a new framework paralleled Fourier neural operator (PFNO) for efficiently training the FNO-based solver given multiple source locations and frequencies.
• [04931] Physics-informed variational inference for stochastic differential equations
  • Format : Talk at Waseda University
  • Author(s) :
    • Hyomin Shin (POSTECH)
    • Minseok Choi (POSTECH)
  • Abstract : In this talk, we propose a physics-informed learning based on variational autoencoder (VAE) to solve data-driven stochastic differential equations. We adopt VAE to extract the random state of the governing equation, and train the model by maximizing the evidence lower bound that incorporates the given physical laws. We present numerical examples to demonstrate the effectiveness of the proposed method.

MS [00974] Finite element complexes and multivariate splines

room : E703

• [05444] Bounds on smooth spline spaces
  • Format : Online Talk on Zoom
  • Author(s) :
    • Henry Schenck (Auburn University)
    • Michael Stillman (Cornell University)
    • Beihui Yuan (Swansea University)
  • Abstract : For a planar simplicial complex Delta contained in R^2, Schumaker proved that a lower bound on the dimension of the space C^r_k(Delta) of planar splines of smoothness r and polynomial degree at most k on Delta is given by a polynomial P_Delta(r,k), and Alfeld-Schumaker showed this polynomial gives the correct dimension when k >= 4r+1. We prove that the equality dim C^r_k(Delta)= P_Delta(r,k) cannot hold in general for k <= (22r+7)/10.
• [04982] Conforming Finite Element Methods with Arbitrary Smoothness in Any Dimension
  • Format : Talk at Waseda University
  • Author(s) :
    • Jun Hu (Peking University)
    • Ting Lin (Peking University)
    • Qingyu Wu (Peking University)
  • Abstract : This talk proposes a construction of $C^r$ conforming finite element spaces with arbitrary $r$ in any dimension. It is shown that if $k ≥ 2^d r + 1$ the space $P_k$ of polynomials of degree $≤ k$ can be taken as the shape function space of $C^r$ finite element spaces in $d$ dimensions. This is the first work on constructing such $C^r$ conforming finite elements in any dimension in a unified way.
• [03133] An algebraic framework for geometrically continuous splines
  • Format : Talk at Waseda University
  • Author(s) :
    • Angelos Mantzaflaris (Inria at Universite Cote d'Azur, Sophia Antipolis, France)
    • Bernard Mourrain (Inria at Universite Cote d'Azur, Sophia Antipolis, France)
    • Nelly Villamizar (Swansea University)
    • Beihui Yuan (Swansea University)
  • Abstract : Geometrically continuous splines are piecewise polynomials defined on a collection of patches stitched together through transition maps. In this talk, we introduce an algebraic framework to study geometrically continuous splines. This framework enables us to use algebraic tools to analysis the dimension of spline spaces, and to present a new algorithm to construct bases using algebraic methods. This talk is based on a joint work with Angelos Mantzaflaris, Bernard Mourrain and Nelly Villamizar.
• [05200] Multivariate spline functions on "oranges"
  • Format : Talk at Waseda University
  • Author(s) :
    • Nelly Villamizar (Swansea University)
    • Maritza Sirvent (The Ohio State University)
    • Tatyana Sorokina (Towson University)
    • Beihui Yuan (Swansea University)
    • Michael DiPasquale (University of South Alabama)
  • Abstract : A spline is a piecewise polynomial function defined on a partition of a real domain. Splines play an important role in many areas such as finite elements, computer-aided design, and data fitting. In the talk, we will focus on splines defined on "oranges" which are partitions composed of a finite number of simplices of the same dimension that share one common lower dimensional face. For any fixed maximal polynomial degree and minimum order of global smoothness, we prove that the dimension of the spline space on an orange can be computed as a sum of the dimension of spline spaces on simpler lower-dimensional partitions. The examples and results in the atalk combine both Bernstein-Bézier methods for splines and algebraic tools.

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

room : E705

• [04765] Mathematical modeling and numerical approximation of bulk-surface model
  • Author(s) :
    • Xueping Zhao (University of Nottingham Ningbo China)
  • Abstract : In biological systems, many molecules, such as proteins and RNAs can phase separate and form liquid condensates in living cells. Many of those biological molecules can bind to the biological surfaces with some domains. How the kinetic processes are affected by surface binding is still unknown. Here, we derive the governing equations of the bulk-membrane coupled system with membrane-binding using irreversible thermodynamic theory. A three-dimensional numerical solver for kinetic equations is developed to study the effects of membrane binding on the various kinetic process. Our results suggest that membrane binding play crucial roles in the underlying physical principles(e.g. time scales) of kinetic processes of the bulk-membrane system.
• [03552] High-order exponential integrators for semilinear parabolic equations with nonsmooth data
  • Author(s) :
    • Shu MA (City University of Hong Kong)
    • Buyang Li (The Hong Kong Polytechnic University)
  • Abstract : A multistep exponential integrator is proposed for the semilinear parabolic equation with nonsmooth initial data, using variable stepsizes and contour integral approximations to address the initial singularity. The approach is extended to the semilinear subdiffusion equation with nonsmooth initial data. We propose an exponential convolution quadrature that combines contour integral representation of the solution, quadrature approximation of contour integrals, multistep exponential integrators for ordinary differential equations, and locally refined stepsizes to resolve the initial singularity. The proposed k-step exponential integrator and exponential convolution quadrature can have kth-order convergence for bounded measurable solutions of the semilinear parabolic and subdiffusion equations, respectively, based on the natural regularity of the solutions corresponding to the bounded measurable initial data.
• [02279] Discovery of Governing Equations with Recursive Deep Neural Networks
  • Author(s) :
    • Jia Zhao (Utah State University)
  • Abstract : In this talk, I will focus on the model discovery problem when the data is not efficiently sampled. This is common due to limited experimental accessibility and labor/resource constraints. Specifically, we introduce a recursive deep neural network (RDNN) for data-driven model discovery. By embedding the known physics knowledge, this recursive approach can retrieve the governing equation in a simple and efficient manner, and it can significantly improve the approximation accuracy by increasing the recursive stages.

MS [01088] Differential Equations meet Data: Scientific Machine Learning for Cardiovascular Applications

room : E708

• [04634] Scientific machine learning approaches for many-query problems in cardiovascular applications
  • Format : Online Talk on Zoom
  • Author(s) :
    • Stefano Pagani (MOX, Department of Mathematics, Politecnico di Milano)
    • Francesco Regazzoni (MOX, Dipartimento di Matematica, Politecnico di Milano)
    • Luca Dede' (Politecnico di Milano)
    • Alfio Quarteroni (Politecnico di Milano, EPFL)
  • Abstract : In many cardiovascular applications, only partial and (possibly) noisy measurements of the phenomenon are available, limiting data-driven techniques in robustly reconstructing quantities of interest. Scientific machine learning approaches compensate for this partial information by integrating physics-based parametric differential models into machine/deep learning models, enabling efficient and accurate solutions to inverse or parameter estimation problems. In this talk, we present some numerical examples of scientific machine learning strategies in computational medicine.
• [04639] GPU-Parallel Cardiac Simulation
  • Format : Talk at Waseda University
  • Author(s) :
    • Toby Simpson (Università della Svizzera italiana)
    • Rolf Krause (Università della Svizzera italiana)
  • Abstract : The computational cost of current approaches to whole heart simulation make them impractical for research or clinical application. We compute a complete description of a human heartbeat, including electrophysiology, solid mechanics and fluid dynamics, on a single Graphics Processing Unit (GPU) within a few minutes. The implementation via a matrix- and mesh-free Finite Volume discretisation, is simple enough to allow patient-specific fitting or provide ground truth data to machine learning algorithms.
• [05161] In-silico perivascular flow and transport
  • Format : Online Talk on Zoom
  • Author(s) :
    • Marie Elisabeth Rognes (Simula Research Laboratory)
  • Abstract : Your brain has its own waterscape: whether you are reading, thinking or sleeping, fluid flows through or around the brain tissue, clearing waste in the process. These biophysical processes are crucial for the well-being and function of the brain. In spite of their importance we understand them but little. In this talk, I will give an overview of mathematical, mechanical and numerical approaches to gain new insight into mechanisms underlying brain clearance.
• [04430] Lipschitz Stabilised Autoencoders in Parameter Identification of Dynamical Systems
  • Format : Talk at Waseda University
  • Author(s) :
    • Haibo Liu (Inria Paris)
    • Damiano Lombardi (Inria Paris)
    • Muriel Boulakia (Université de Versailles et Saint-Quentin en Yveline)
  • Abstract : The present work deals with data-driven modelling. Given a set of partial noisy observations of a dynamical system, we investigate using the Lipschitz stabilised auto-encoder to perform an intrinsic dimension estimation to understand how many parameters are responsible for the observed variability. By incorporating the information of the intrinsic dimensionality, we investigate a data-driven model that can complement the classical parameter identification method with the help of data.

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

room : E709

• [04029] Obstacles and interfaces composite scattering in a multilayered medium
  • Format : Talk at Waseda University
  • Author(s) :
    • Lei Zhang (Zhejiang University of Technology)
  • Abstract : This talk will focus on the mathematical analysis and numerical methods for the composite scattering problem from obstacles and interfaces in a multilayered medium. We will highlight some recent progress in this area. Specifically, we will address how to handle obstacles and rough surfaces, and how to model scattering from unbounded surfaces. We will also discuss the well-posedness and numerical methods for solving these problems based on the characteristic of the scattering problems.
• [04887] Lippmann Schwinger integral equation for fiber optics analysis
  • Format : Talk at Waseda University
  • Author(s) :
    • Felipe Vico (UPV)
    • Miguel Ferrando-Bataller (UPV)
    • Eva Antonino-Daviu (UPV)
    • Marta Cabedo-Fabrés (UPV)
  • Abstract : In this talk, we will present a Limpann-Schwinger integral formulation for accurately calculating the propagating modes in fiber optics. Our formulation is based on a second-kind integral equation, which ensures stability in the presence of noise and uncertainties. Furthermore, our discretization scheme exhibits superalgebraic convergence for smooth refractive index fibers, making it suitable for graded-index fibers.
• [05178] Single-excitation quantum optics: analysis and algorithms
  • Format : Talk at Waseda University
  • Author(s) :
    • Jeremy Graeme Hoskins (University of Chicago)
    • Jeremy Hoskins (University of Chicago)
    • Manas Rachh (Flatiron Institute)
    • John Schotland (Yale University)
    • Jason Kaye (Flatiron Institute, Simons Foundation)
  • Abstract : Recent progress in experimental quantum optics has facilitated the physical construction of systems of increasing complexity. Of particular importance are experiments involving the scattering of one or two photons from a collection of atoms. In this context, a central question is to understand the time evolution of the entanglement between atoms, mediated by the field. In this talk we will discuss analytical results on the properties of these systems, and how those properties depend on disorder or distribution of the locations of the atoms.
• [05639] Poisson Solver for Complicated Geometries in R3 Using Function Extension
  • Author(s) :
    • Fredrik Fryklund (New York University)
    • Charles Epstein (Flatiron Institute, Simons Foundation)
    • Shidong Jiang (Flatiron Institute, Simons Foundation)
    • Leslie Greengard (Flatiron Institute, Simons Foundation)
  • Abstract : We describe a new, adaptive solver for the three-dimensional Poisson equation in complicated geometries. The solution is represented as the sum of a volume potential and a double layer potential. The source data is extended with high order accuracy along the normals to the surface, to a geometrically simpler region. This allows us to accelerate the evaluation of the volume potential using an FMM.

MS [00919] Recent Advances in Hybridizable Discontinuous Galerkin Methods and Applications

room : E710

• [03033] A C0 interior penalty method for mth-Laplace equation
  • Author(s) :
    • Weifeng Qiu (City University of Hong Kong)
    • Huangxin Chen (Xiamen University)
    • Jingzhi Li (Southern University of Science and Technology)
  • Abstract : In this paper, we propose a 𝐶0 interior penalty method for 𝑚th-Laplace equation on bounded Lipschitz polyhedral domain in R𝑑, where 𝑚 and 𝑑 can be any positive integers. The standard 𝐻1-conforming piecewise 𝑟-th order polynomial space is used to approximate the exact solution 𝑢, where 𝑟 can be any integer greater than or equal to 𝑚. Unlike the interior penalty method in Gudi and Neilan [IMA J. Numer. Anal. 31 (2011) 1734–1753], we avoid computing 𝐷^𝑚 of numerical solution on each element and high order normal derivatives of numerical solution along mesh interfaces. Therefore our method can be easily implemented. After proving discrete 𝐻𝑚-norm bounded by the natural energy semi-norm associated with our method, we manage to obtain stability and optimal convergence with respect to discrete 𝐻𝑚-norm.
• [03873] Output-Adaptive Hybridized Discontinuous Finite Elements for Efficient Flow Computations
  • Author(s) :
    • Krzysztof Fidkowski (University of Michigan)
  • Abstract : Discontinuous Galerkin (DG) methods have enabled accurate computations of complex flowfields, yet their memory footprint and computational costs are large. Hybridized discontinuous Galerkin (HDG/EDG) methods reduce the number of globally-coupled degrees of freedom by decoupling elements and stitching them together through weak flux continuity. However, these methods have not risen to nearly the same level of popularity as DG, and in this work we outline reasons why and demonstrate benefits in an output-based adaptive setting.
• [04227] Towards boundary conditions for HDG methods for direct aeroacoustic computations
  • Author(s) :
    • Philip Lukas Lederer (University of Twente)
    • Jan Ellmenreich (TU Wien)
  • Abstract : We focus on direct aeroacoustic simulations using hybrid discontinuous Galerkin methods (HDG) for the approximation of the compressible Navier-Stokes equations. A crucial factor for accurate results is the proper handling of artificial boundary conditions, focusing on the reflectivity of the acoustic waves. We discuss various approaches such as LODI relations and extensions of characteristic Navier-Stokes boundary conditions (NSCBC) for HDG methods. Numerical results are presented and discussed in detail.
• [04312] Hybrid discontinuous Galerkin methods on multiple levels
  • Author(s) :
    • Guido Kanschat (Heidelberg University)
    • Peipei Lu (Soochow University)
    • Roland Maier (University of Jena)
    • Andreas Rupp (LUT University)
  • Abstract : Hybrid finite element schemes approximate the trace of an unknown solution to a partial differential equation on the mesh skeleton (the union of the faces in a mesh). Afterward, these schemes use this trace approximation to recover the primal and dual unknowns. This strategy has several advantages over standard finite elements, such as an enhanced order of convergence, smaller symmetric positive systems of linear equations, and preservation of physically meaningful quantities. Virtually all of the available multilevel (multigrid and multiscale) techniques for finite elements exploit the fact that their test and trial spaces are nested. However, the test and trial spaces are not nested for hybrid finite elements because their main approximate lives on the mesh's skeleton, which grows with refinement. Thus, the major obstacle that blocks the way to practical multigrid methods comprises the construction of stable mesh transfer operators. Several recent works have addressed this issue by exchanging the hybrid formulation for a non-hybrid formulation in a preliminary step. Afterward, these approaches use the available multilevel strategies for non-hybrid finite elements. We proceed differently and preserve the advantageous properties of hybrid finite elements on all mesh levels. To this end, we devise stable mesh transfer operators and provide relevant convergence results for our hybrid, multilevel finite elements. This approach allows us to use identical discretizations on all mesh levels (homogeneous strategy) instead of the heterogeneous methods that use different discretizations on different mesh levels.

contributed talk: CT114

room : E711

[00175] pFemView: An Open-Source Visualization Library for p-FEM

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E711
• Type : Contributed Talk
• Abstract : We present a new approach to visualize p-hierarchical basis finite element (p-FEM) solutions on the scientific visualization application ParaView. Since ParaView uses a linear/quadratic interpolation at specific geometric nodes, a refined visualization mesh needs to be constructed efficiently. This is accomplished via the key steps “p-hierarchical to nodal projection” and “higher-order to lower-order projection”, which have been implemented in an open-source C++ library “pFemView”. Furthermore, examples are presented to illustrate the effectiveness of this library.
• Classification : 65N30, 65Y15, 68-04
• Format : Talk at Waseda University
• Author(s) :
  • Janitha Gunatilake (University of Peradeniya)

[00577] Mixed Finite Element Method for Dirichlet Boundary Optimal Control Problem

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E711
• Type : Contributed Talk
• Abstract : The optimal control problems (OCPs) subjected to partial differential equations (PDEs) have numerous applications in fluid dynamics, image processing, mathematical finance etc. The objective of OCPs is to find the optimal control which minimizes or maximizes the given cost functional with certain constraints being satisfied. There are mainly two types of OCPs available in literature namely, Distributed Control Problems where the control acts on the system through an external force and Boundary Control Problems where the control acts on the system through a Dirichlet or Neumann or Robin boundary conditions. Dirichlet boundary control problems are difficult to handle due to variational difficulty. In many applications, it is important to obtain accurate approximation of the scalar variable and its gradient simultaneously. A common way to achieve this goal is to use mixed finite element methods. The main aim of my talk is to analyze the mixed finite element method for the second order Dirichlet boundary control problem in which the control is penalized in the energy space. Mixed finite element methods have the property that they maintain the discrete conservation law at the element level. For the variational formulation, the state equation is converted to the mixed system using the mixed variational scheme for second order elliptic equations and then the continuous optimality system is derived. In order to discretize the continuous optimality system, the lowest order Raviart-Thomas space is used to numerically approximate the state and co-state variables whereas the continuous piece-wise linear finite element space is used for the discretization of control. Based on this formulation, the optimal order a priori error estimates for the control in the energy norm and $L_2$-norm is derived. The reliability and the efficiency of proposed a posteriori error estimator is also discussed using the Helmholtz decomposition. Finally, several numerical experiments are presented to confirm the theoretical findings.
• Classification : 65N30, 65N15, 65N12, 65K10
• Format : Online Talk on Zoom
• Author(s) :
  • Divay Garg (Indian Institute of Technology Delhi)
  • Kamana Porwal (Indian Institute of Technology Delhi)

[00741] POINTWISE ADAPTIVE QUADRATIC DG FEM FOR OBSTACLE PROBLEM

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E711
• Type : Contributed Talk
• Abstract : The obstacle problem, often considered as a prototype for a class of free boundary problems. The elliptic obstacle problem is a nonlinear model that describes the vertical movement of a object restricted to lie above a barrier $\text{(obstacle)}$ while subjected to a vertical force. In this talk, we perform a posteriori error analysis in the supremum norm for the quadratic Discontinuous Galerkin$\text{(DG)}$ method for the elliptic obstacle problem. Compare with the energy norm estimates, supremum norm estimates gives the pointwise control on the error. We have carried out the analysis on two different discrete sets, one set having integral constraints and other one with the nodal constraints at the quadrature points, and discuss the pointwise reliability and efficiency of the proposed a posteriori error estimator. In the analysis, we employ a linear averaging function to transfer DG finite element space to standard conforming finite element space and exploit the sharp bounds on the Green's function of the Poisson's problem. Moreover, the upper and the lower barrier functions corresponding to continuous solution $u$ are constructed by modifying the conforming part of the discrete solution $u_h$ appropriately. Finally, the numerical results for adaptive FEM are presented in order to exhibit the reliability and the efficiency of the proposed error estimator.
• Classification : 65N30, 65N15
• Format : Talk at Waseda University
• Author(s) :
  • Ritesh Ritesh (Indian Institute of Technology, Delhi)
  • Rohit Khandelwal (Indian Institute of Technology, Delhi)
  • Kamana Porwal (Indian Institute of Technology, Delhi)

[01573] A novel robust adaptive algorithm for time fractional diffusion wave equation on non-uniform meshes

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E711
• Type : Contributed Talk
• Abstract : In this work, a novel high-order adaptive algorithm on non-uniform grid points for the Caputo fractional derivative is derived. Developed algorithm allows one to build adaptive nature where numerical scheme is adjusted according to behavior of $\alpha$ to keep errors very small and converge to solution very fast. Analysis of numerical scheme has been established thoroughly. Moreover, a reduced order technique is implemented by using moving mesh refinement to improve accuracy at several time levels.
• Classification : 65N06, 65N12, 65N50, 65N15
• Format : Online Talk on Zoom
• Author(s) :
  • Rahul Kumar Maurya (Government Tilak P.G. College, Katni, Madhya Pradesh, India)
  • Vineet Kumar Singh (Indian Institute of Technology (BHU), Varanasi, India)

[01846] L3 approximation of the Caputo derivatives and its application to time-fractional wave equation

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E711
• Type : Contributed Talk
• Abstract : In this talk, we will discuss a new second-order L3 approximation of the Caputo fractional derivative of order 1< α < 2. We have applied Lagrange’s cubic interpolating polynomial to develop this approximation. A second-order difference scheme is also proposed to find the numerical solution of the time-fractional wave equation. The numerical analysis results of the proposed algorithm are provided and a comparative study is also given to show the effectiveness and accuracy of the proposed scheme.
• Classification : 65N06
• Format : Online Talk on Zoom
• Author(s) :
  • NIKHIL SRIVASTAVA (Indian Institute of Technology (BHU) Varanasi, India)

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

room : E802

• [00243] A finer singular limit of the Kobayashi-Warren-Carter type functional and its gradient flow
  • Format : Talk at Waseda University
  • Author(s) :
    • Masaaki Uesaka (Arithmer, Inc.)
    • Yoshikazu Giga (the University of Tokyo)
    • Koya Sakakibara (Okayama University of Science)
    • Jun Okamoto (Kyoto University)
  • Abstract : We consider the singular limit of the Kobayashi-Warren-Carter type energy, which is derived from the physical model of grain boundary motion in polycrystals. The KWC-type energy contains the weighted total variation, and hence we must employ a topology finer than $L1$ to capture the singular limit's behavior in detail. We shall explain the key result of the singular limit of KWC-type energy and the behavior of its gradient flow.
• [00249] Variational modeling of fluid in poroelastic medium
  • Format : Talk at Waseda University
  • Author(s) :
    • Arkadz Kirshtein (Tufts University)
    • James Haley Adler (Tufts University)
    • Xiaozhe Hu (Tufts University)
  • Abstract : In this talk I will discuss modeling fluid flow through a deformable porous medium. I will start from introducing a variational approach for fluids and elasticity in Lagrangian coordinates. Next I will discuss an existing approach based on Biot's consolidation model. Ultimately I will introduce a system derived using energetic variational approach and discuss numerical methods and simulations based on it.
• [00226] Phase field model for volume-preserving mean curvature flow
  • Format : Talk at Waseda University
  • Author(s) :
    • Keisuke Takasao (Kyoto University)
  • Abstract : In this talk, we show a global existence of the weak solution for the volume-preserving mean curvature flow. To construct the weak solution, we use the Allen-Cahn equation with non-local term given by the penalty method. We prove the $L^2$-estimate of the non-local term and the monotonicity formula for the equation, which are the keys of the proof of the existence theorem.
• [00257] A unified continuum model for grain boundary dynamics incorporating microscopic structure
  • Format : Talk at Waseda University
  • Author(s) :
    • Yang Xiang (Hong Kong University of Science and Technology)
  • Abstract : We develop a unified continuum framework to account for the underlying line defect mechanisms. Conditions on the continuum level are imposed to account for the underlying microscopic mechanisms, which makes the continuum model more efficient to describe the collective behaviors of grain boundary networks at larger length scales.

MS [00704] Numerical Software Libraries Enabling Benefits to Scientific Applications

room : E803

• [01830] Overview and Application Experiences with SUNDIALS
  • Format : Talk at Waseda University
  • Author(s) :
    • Carol Woodward (Lawrence Livermore National Laboratory)
    • Cody Balos (Lawrence Livermore National Lab)
    • David Gardner (Lawrence Livermore National Laboratory)
    • Daniel Reynolds (Southern Methodist University)
  • Abstract : The SUNDIALS library of time integrators and nonlinear solvers has recently increased its support for large-scale GPU-based systems through new data structures and solver package interfaces. This talk will overview the SUNDIALS packages and recently added capabilities then show results on newly deployed systems. Several applications have taken advantage of these capabilities to improve their time integration performance, and results from a selection of these, including combustion, phase field modeling, and cosmology, will be shown. Prepared by LLNL under Contract DE-AC52-07NA27344. LLNL-ABS-844590.
• [01626] Experience with Exascale Applications using PETSc/TAO
  • Format : Talk at Waseda University
  • Author(s) :
    • Todd Munson (Argonne National Laboratory)
  • Abstract : In this presentation, we will discuss the extensions of the PETSc/TAO library to support the GPU-based Frontier and Aurora exascale systems and provide some available performance results. We will then provide some perspectives on using PETSc/TAO from an application point of view and conclude with thoughts on future needs to support next generation architectures.
• [01703] On the Design and Performance of Exascale Applications using the Trilinos Solver Framework
  • Format : Talk at Waseda University
  • Author(s) :
    • Roger Pawlowski (Sandia National Laboratories)
  • Abstract : The Trilinos project supplies algorithms and enabling technologies for the solution of large-scale, complex multi-physics engineering and scientific problems on new and emerging high-performance computing architectures. Capabilities include performance portability abstractions, linear solvers, preconditioners, nonlinear solvers, time integration and finite element discretization tools. This talk will focus on recent achievements in developing exascale applications using Trilinos. We will show results from plasma physics simulations for electromagnetic environments and aerodynamics simulations for hypersonic reentry.
• [01837] Paving the road for efficient volume coupling with preCICE
  • Format : Talk at Waseda University
  • Author(s) :
    • David Schneider (University of Stuttgart)
    • Benjamin Uekermann (University of Stuttgart)
  • Abstract : preCICE is an open-source coupling library enabling partitioned multi-physics simulations of separated software packages. It offers methods for data communication, equation coupling, and data mapping. This talk presents new data mapping concepts in preCICE in terms of efficiency and accuracy, which enable users to apply preCICE for large-scale coupling scenarios. The relevance of these new data mapping concepts is demonstrated by showing user-provided example cases.

MS [00047] Combining Machine Learning and Stochastic Methods for Modeling and Forecasting Complex Systems

room : E804

• [03378] Generative modelling through diffusion maps
  • Format : Talk at Waseda University
  • Author(s) :
    • Georg A. Gottwald (University of Sydney)
    • Sebastian Reich (Universität Potsdam)
    • Fengyi Li (MIT)
  • Abstract : We propose a Langevin sampler as a generative modelling method. The Langevin sampler is constructed using diffusion maps. We show how this method can be used to perform inverse modelling tasks as well as providing a stochastic subgrid-scale parametrisation.
• [04604] Tracer Prediction in Simplified Stochastic Geophysical Models through Kalman Filters and Related Methods
  • Format : Talk at Waseda University
  • Author(s) :
    • Mustafa A Mohamad (University of Calgary)
  • Abstract : Transport-dominated phenomena represents a major challenge for reduction techniques due to the presence of nonlinear coherent wave structures. Here we discuss the assimilation and prediction of a turbulent complex flow field given a stream of measurements provided by passively advected Lagrangian drifters. We quantify recovery of the Eulerian energy spectra from observations of Lagrangian drifters by special data assimilation algorithms. We primarily focus on algorithms based on Kalman filters, but also discuss related methods for comparison. The focus is on statistical properties of the tracer.
• [05043] Machine Learning for Stochastic Parametrisation
  • Format : Online Talk on Zoom
  • Author(s) :
    • Hannah Christensen (University of Oxford)
  • Abstract : The use of stochastic techniques in atmospheric models to characterise uncertainty in small-scale processes has proved beneficial for forecasts on weather, seasonal and climate timescales. We have also recently seen significant progress in replacing the parametrisation schemes which represent these small-scale processes using machine learning (ML). This has the potential to speed up and improve numerical models. In this presentation I bring together these two developments, and discuss approaches to use ML for stochastic parametrisation.
• [03280] Explainable AI to Detect, Predict and Discover Climate Variability and Change
  • Format : Online Talk on Zoom
  • Author(s) :
    • Elizabeth Barnes (Colorado State University)
  • Abstract : Earth’s climate is chaotic and noisy. Finding usable signals amidst all of the noise can be challenging: be it predicting if it will rain, knowing which direction a hurricane will go, understanding the implications of melting Arctic ice, or detecting the impacts of human-induced climate warming. Here, I will demonstrate how explainable artificial intelligence (XAI) techniques can sift through vast amounts of climate data and push the bounds of scientific discovery: allowing scientists to ask “why?” but now with the power of machine learning.

contributed talk: CT123

room : E811

[00180] Relationship between musical notes and socio-political events

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E811
• Type : Contributed Talk
• Abstract : Historians and scientists long suspected that sounds and music impact different cultures. However, empirical data to support such claim is sparse. Previous research using Supervised Machine Learning algorithms, i.e. ANFIS (Adaptive Neuro-Fuzzy Inference System) has successfully categorised musical genre classification and predicted the outcome of the United Kingdom's election results using popular music released in that period by feeding sound wave features to the ANFIS algorithm. This study reports similar research for the Moroccan elections using two different supervised machine learning algorithms namely, k-NN and SVM.
• Classification : 68T09, 91C99
• Format : Talk at Waseda University
• Author(s) :
  • Choi-Hong Lai (University of Greenwich)
  • Nakunam Kokulan (University of Greenwich)
  • Yahya Chahine (University of Greenwich)

[01150] Optimizing Tool Assignment Using Smart Lockers

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E811
• Type : Industrial Contributed Talk
• Abstract : A logistics operator adopted smart lockers to distribute 150 commercial tools such as tablets and scanners to employees, working in 3 shifts. The lockers gather significant data like tools deficiencies, breakdowns, usage time, punctuality. The assignment policy to deliver tools must minimize downtime using two figure of merit, one classifying employees according to their ability to handle tools, and another measuring the frequency of deficiencies and breakdowns. The proposal is inspired in genetic algorithms.
• Classification : 68T20, 90B06
• Format : Talk at Waseda University
• Author(s) :
  • Jose Alberto Fonseca (Instituto de Telecomunicações - Universidade de Aveiro)
  • Joaquim Ferreira (Instituto de Telecomunicacoes, Universidade de Aveiro)
  • Ricardo Bandeira (Microio,Lda)
  • Fernanda Coutinho (Instituto Superior de Engenharia de Coimbra - IPP)

[02276] Detection Topic of Bjorka Using LSTM with LDA

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E811
• Type : Contributed Talk
• Abstract : This paper presents topic modeling for Hacker Bjorka using LSTM with LDA. The Research purpose is to analyze the public opinion of Bjorka and the topics related to him in the online community. The findings reveal that the majority of the public perception of Bjorka is positive, with accuracy of 80,26% and perplexity of -8,28. This study provides a valuable contribution to the field of computational text analysis and its applications in the online community.
• Classification : 68T07
• Author(s) :
  • Muhammad Muhajir (Universitas Gadjah Mada )
  • Dedi Rosadi (Universitas Gadjah Mada )

[02326] Multi-level Wavelet Convolutional Neural Networks for Classifying Lung Cancer

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E811
• Type : Contributed Talk
• Abstract : Lung cancer classification becomes significant as it can increase the survival rate. Our previous study to classify lung cancer using Recurrent Neural Networks (RNN) and Wavelet RNN intensify accuracy by 2.7%. It may increase with the computational complexity. Thus, in this research, we focus classifying lung cancer using deep learning Neural Networks that has been successfully applied in practice. A model called Multi-level Wavelet Convolutional Neural Networks. This study provides more discussion on Neural Networks and lung cancer classification.
• Classification : 68T07
• Format : Online Talk on Zoom
• Author(s) :
  • Devi Nurtiyasari (Gadjah Mada University)
  • Dedi Rosadi (Gadjah Mada University)
  • Abdurakhman Abdurakhman (Gadjah Mada University)

[02329] Improve Error Prediction Using Regularization Model for Movie Recommendation System

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E811
• Type : Contributed Talk
• Abstract : Currently, most applications (such as Netflix, Spotify, and the others) provide engaging facilities to improve the user’s experience. These applications highly depend on the effectiveness of their recommendation systems. The goal for this paper was to improve error prediction (RMSE and MAE) using Regularization model compared with state-of-art models. The proposed technique obtains a better result than a state-of-art model with an improvement of 0.48% and 1.43% on error prediction using ML-1M dataset, respectively.
• Classification : 68T07, 68T09, Machine Learning
• Format : Online Talk on Zoom
• Author(s) :
  • Malim Muhammad (Universitas Gadjah Mada)
  • Dedi Rosadi (Universitas Gadjah Mada)
  • Danardono Danardono (Universitas Gadjah Mada)

MS [00638] Minisymposium on Interaction between Harmonic Analysis and Data Science

room : E812

• [01801] Algorithms for quantizing neural networks with guaranteed accuracy
  • Format : Talk at Waseda University
  • Author(s) :
    • Rayan Saab (University of California San Diego)
  • Abstract : We present both deterministic and stochastic algorithms for quantizing neural networks, which can achieve significant savings in cost, computation time, memory, and power consumption while preserving the network's performance. Our methods are data-driven, computationally efficient, and have provable error guarantees. We showcase our results through numerical experiments on large multi-layer networks. Time permitting, we also discuss open problems and connections to other areas of research. This is joint work, in parts, with Jinjie Zhang, Yixuan Zhou, and Johannes Maly.
• [01538] Learning nonlinear functionals using deep ReLU networks
  • Format : Talk at Waseda University
  • Author(s) :
    • Linhao Song (City University of Hong Kong)
    • Jun Fan (Hong Kong Baptist University)
    • Dingxuan Zhou (University of Sydney)
  • Abstract : Functional neural networks have been proposed and studied in order to approximate nonlinear continuous functionals defined on $L^p([-1, 1]^s)$ for integers $s\ge1$ and $1\le p<\infty$. However, their theoretical properties are largely unknown beyond universality of approximation or the existing analysis does not apply to the rectified linear unit $\left(\hbox{ReLU}\right)$ activation function. In this talk we investigate the approximation power of functional deep ReLU networks and establish their rates of approximation under mild regularity conditions.
• [01578] Compressed sensing for the sparse Radon transform
  • Format : Talk at Waseda University
  • Author(s) :
    • Giovanni S. Alberti (University of Genoa)
    • Matteo Santacesaria (University of Genoa)
    • S. Ivan Trapasso (Polytechnic University of Turin)
    • Alessandro Felisi (University of Genoa)
  • Abstract : Compressed sensing allows for the recovery of signals from a number of measurements that is proportional, up to logarithmic factors, to their sparsity. The classical theory considers random linear measurements or subsampled isometries, with applications to, e.g., MRI. I will show how compressed sensing can be applied to the sparse Radon transform, where a finite number of angles are considered. The result follows from a new theory of compressed sensing for infinite-dimensional ill-posed problems.
• [01808] Super-resolution of sparse measures: recent advances
  • Format : Online Talk on Zoom
  • Author(s) :
    • Dmitry Batenkov (Tel Aviv University)
  • Abstract : The problem of sparse super-resolution asks to recover a linear combination of Dirac point measures from low-frequency and inaccurate measurements. This is a popular model for applications including spectral estimation, direction of arrival, imaging of point sources, and sampling of signals below the Nyquist limit. In this talk I will describe recent results on deriving optimal recovery bounds and corresponding algorithms for this model and its generalizations to sparse distributions defined on homogeneous Riemannian manifolds.

MS [00951] Steps Toward Robust and Stable Artificial Intelligence

room : E818

• [03569] Adversarial Ink: Componentwise Backward Error Attacks on Deep Learning
  • Format : Online Talk on Zoom
  • Author(s) :
    • Des Higham (University of Edinburgh)
    • Lucas Beerens (University of Edinburgh)
  • Abstract : Deep neural networks are capable of state-of-the-art performance in many classification tasks. However, they are known to be vulnerable to adversarial attacks---small perturbations to the input that lead to a change in classification. We address this issue from the perspective of backward error and condition number, concepts that have proved useful in numerical analysis. To do this, we build on the work of Beuzeville et al. (2021). In particular, we develop a new class of attack algorithms that use component-wise relative perturbations. Such attacks are highly relevant in the case of handwritten documents or printed texts where, for example, the classification of signatures, postcodes, dates or numerical quantities may be altered by changing only the ink consistency and not the background. This makes the perturbed images look natural to the naked eye. Such "adversarial ink" attacks therefore reveal a weakness that can have a serious impact on safety and security. We illustrate the new attacks on real data and contrast them with existing algorithms. We also study the use of a componentwise condition number to quantify vulnerability.
• [05048] On the extended Smale’s 9th problem, phase transitions in optimisation and the limits of AI
  • Format : Talk at Waseda University
  • Author(s) :
    • Alexander James Bastounis (Leicester University)
  • Abstract : Instability is the Achilles’ heel of AI and a paradox, with typical training algorithms unable to recover stable neural networks (NNs). Hence the fundamental question: can one find algorithms that compute stable and accurate NNs? If not, what are the foundational barriers we encounter across machine learning? These questions are linked to recent results on the extended Smale’s 9th problem, which uncovers new phase transitions in optimisation and yields barriers on the computation of NNs.
• [04061] Intrinsic dimensionality of real-life datasets in biomedicine and drug discovery
  • Format : Online Talk on Zoom
  • Author(s) :
    • Andrey Zinovyev (Evotec)
  • Abstract : Intrinsic dimensionality (ID) is the most essential characteristic of a multidimensional data point cloud which determines the reliability and stability of the application of all machine learning methods. We provide a toolbox for estimating ID, and we benchmark it using several hundreds of real-life datasets. We demonstrate how data ID affects the results of applying deep classifiers and generative data models in biomedicine and drug discovery domains that allow the user to judge the prediction robustness.
• [05037] Generalised hardness of approximation and hallucinations -- On barriers and paradoxes in AI for image reconstruction
  • Format : Online Talk on Zoom
  • Author(s) :
    • Anders Hansen (University of Cambridge)
  • Abstract : AI techniques are transforming medical imaging with striking performance. However, these new methods are susceptible to AI generated hallucinations, the phenomenon where realistically looking artefacts are incorrectly added to the reconstructed image, causing serious concerns in the sciences. The basic question is therefore: can hallucinations be prevented? This question turns out to be linked to a newly discovered phenomenon in the foundations of computational mathematics: generalised hardness of approximation, demonstrating methodological barriers in AI.

MS [00255] Recent developments in fast algorithms for inverse problems and imaging

room : E819

• [04412] Exploiting Mixed Precision Arithmetic in Image Reconstruction
  • Format : Talk at Waseda University
  • Author(s) :
    • James Nagy (Emory University)
  • Abstract : Although some work has been done to exploit mixed precision computations for inverse problems arising in image processing, most previous work focuses on extended precision to avoid the influence of rounding errors. We consider a different perspective: because we cannot expect to precisely know data, we develop and analyze solvers that can take advantage of low precision speed of modern computer architectures, and which can be used in a variety of imaging applications.
• [03595] Image Quality Assessment for Reconstruction Algorithms
  • Format : Talk at Waseda University
  • Author(s) :
    • Anna Breger (University of Cambridge)
  • Abstract : Assessing digital image quality (IQ) is of high importance in numerous applied research fields, such as image acquisition, reconstruction or processing. Automated evaluation is needed since manual evaluation is too time-consuming and expensive for huge data sets and, furthermore, may be biased or introduce inconsistencies. In this talk I will give a short introduction to IQ assessment and provide examples of failure when applying standard full reference IQ measures in medical imaging reconstruction tasks.

contributed talk: CT140

room : E820

[02347] Reduction of High Wave Load on a Sea Wall by an Elastic Plate and a Porous Structure

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E820
• Type : Contributed Talk
• Abstract : The present study investigates the wave impact on a sea wall in the presence of an elastic plate and a finite-width porous structure within the linearized water wave theory framework. By employing eigenfunction expansion, a system of an algebraic equation is obtained and solved. The force, reflection and dissipation coefficients are plotted through graphs to investigate the effect of different system parameters.
• Classification : 76B15
• Format : Talk at Waseda University
• Author(s) :
  • GAGAN SAHOO (IIT ROPAR)
  • SUBASH CHANDRA MARTHA (IIT Ropar)
  • SOFIA SINGLA (IIIT UNA, UNA)

[02407] Scattering of water waves by two horizontal porous plates over a pair of trenches

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E820
• Type : Contributed Talk
• Abstract : The scattering of water waves by two non-uniform horizontal porous plates in the presence of a pair of trenches is modeled using Darcy’s law for flow past a porous plate. The eigenfunction expansions in conjunction with the matching conditions gives rise to an overdetermined system of linear equations, which is solved to obtain the numerical values of physical quantities such as reflection, transmission, dissipation coefficients and force. Different graphs are plotted to visualize the effect of different system parameters. This study highlights two horizontal porous plates over uneven bottom topography will play a vital role in constructing an effective breakwater reducing high wave impact.
• Classification : 76B15
• Format : Talk at Waseda University
• Author(s) :
  • Sunita Choudhary (Indian Institute Technology, Ropar)
  • S. C. Martha (Indian Institute Technology, Ropar)

[02432] Dispersion relation reconstruction for 2D Photonic Crystals based on polynomial interpolation

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E820
• Type : Contributed Talk
• Abstract : A natural way to compute photonic dispersion relation is to restrict the parameters to the edges of the irreducible Brillouin zone (IBZ), which has been formalized as a dangerous simplification. We propose a novel method based on polynomial interpolation to approximate band functions in the whole IBZ. The importance of IBZ interiors, the need to reduce computational cost and our analysis of the regularity of band functions illustrate the necessity and feasibility of our method.
• Classification : 78M22, 26B30, 32A10, 65M60, 41A10
• Format : Talk at Waseda University
• Author(s) :
  • Yueqi Wang (University of Hong Kong)
  • Guanglian Li (University of Hong Kong)

[00665] Estimating pressure distribution on a surface via electrical sensing skin

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E820
• Type : Contributed Talk
• Abstract : Sensing skins allow for monitoring of a surface by electrically imaging a conductive layer on an object. One example is fracture detection of concrete elements by imaging a conductive paint layer. In this talk, we present a way to estimate pressure distribution on a surface by using sensing skin -based techniques.
• Classification : 78-05, 78-10, 65Nxx, Electrical Impedance Tomography
• Author(s) :
  • Petri Kuusela (University of Eastern Finland)
  • Moe Pour-Ghaz (North Carolina State University)
  • Aku Seppänen (University of Eastern Finland)

[00755] A variational approach for nonlinear elasticity

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @E820
• Type : Contributed Talk
• Abstract : This research concerns the Weighted Energy-Dissipation approach for nonlinear elasticity. We introduce a family of $\epsilon-$dependent functionals defined over entire trajectories and we prove that they admit minimisers which are solutions of the corresponding Euler-Lagrange problem. Considering the limit $\epsilon \rightarrow 0$ we prove that those minimisers converge to the solutions of a specific nonlinear elasticity equation. Eventually, linearized elastic energies are proven to be the $\Gamma$-limits of the rescaled nonlinear energies.
• Classification : 74B20, 47J30, 47J35, 58E30, 74B15
• Format : Online Talk on Zoom
• Author(s) :
  • Riccardo Voso (University of Vienna)

MS [01024] Multiscale modeling and simulation methods of inhomogeneity in defected systems

room : D102

• [04025] Recent progress on multiscale coupling for crystalline defects
  • Format : Talk at Waseda University
  • Author(s) :
    • Lei Zhang (Shanghai Jiao Tong University)
    • Yangshuai Wang (University of British Columbia)
  • Abstract : In this talk, we present some recent progress on the multiscale coupling methods for crystalline defects, which include: 1) MeshAC, a three-dimensional mesh package designed for atomistic-to-continuum; 2) (a/c) coupling with higher order far-field boundary conditions; 3) Adaptive QM/MM coupling with machine-learned interatomic potentials (MLIP).
• [02228] Mathematical perspectives in modeling microstructures in metallic materials
  • Format : Online Talk on Zoom
  • Author(s) :
    • Yejun Gu (Agency for Science Technology and Research)
  • Abstract : The mechanical properties of metallic materials are strongly dependent on their microstructural features (e.g. morphology and distribution of dislocations, grains, and other defects). Thus it necessitates a comprehensive understanding of the microstructure evolutions in materails during deformation. I will present some attempts of applying mathematical methods to address this problem. The presentation consists of two parts: one is the fast algorithms for solving partial differential equations, in order to precisely describe the microstructure evolutions; the other is the probabilistic description and statistical analysis, which are employed to quantify the relationship between the microstructures and mechanical properties.
• [04547] A Three-Dimensional Continuum Simulation Method for Grain Boundary Motion Incorporating Dislocation Structure
  • Format : Talk at Waseda University
  • Author(s) :
    • Xiaoxue Qin (Shanghai University)
  • Abstract : We develop a continuum model for the dynamics of grain boundaries in three dimensions that incorporates the motion and reaction of the constituent dislocations. The continuum model is based on a simple representation of densities of curved dislocations on the grain boundary. Illposedness due to nonconvexity of the total energy is fixed by a numerical treatment based on a projection method that maintains the connectivity of the constituent dislocations. An efficient simulation method is developed, in which the critical but computationally expensive long-range interaction of dislocations is replaced by another projection formulation that maintains the constraint of equilibrium of the dislocation structure described by the Frank’s formula. This continuum model is able to describe the grain boundary motion and grain rotation due to both coupling and sliding effects, to which the classical motion by mean curvature model does not apply. Comparisons with atomistic simulation results show that our continuum model is able to give excellent predictions of evolutions of low angle grain boundaries and their dislocation structures.
• [04727] A nonlocal elasiticity model for simulating the static and dynamic problems of crystalline defects in materials
  • Format : Talk at Waseda University
  • Author(s) :
    • Xiaoyin Wang (Wuhan University)
  • Abstract : In this work, we present a nonlocal elasticity model in order to solve the static and dynamic problems related to crystalline defects such as dislocations, interfaces, etc. In our model, a superposition framework based on nonlocal description is used to solve the stress and displacement field due to defects. The interaction of dislocation with other types of defects such as cracks can be modeled with higher accuracy due to the consideration of nonlocal effects. The model is solved by optimization based numerical techniques in order to accelerate the simulations. We also apply this model to problems related to crystal interfaces.

MS [00781] Physical and Mathematical Research on Transport on Slippery Surfaces

room : D401

• [03147] Experimental Applications of Slippery Liquid and Liquid-like-Solid Surfaces
  • Format : Talk at Waseda University
  • Author(s) :
    • Glen McHale (The University of Edinburgh)
    • Gary George Wells (The University of Edinburgh)
    • Rodrigo Ledesma-Aguilar (The University of Edinburgh)
  • Abstract : The liquid Amontons’ laws relate drop friction along a surface to the normal component of the capillary force. Here I outline work on low pinning surfaces which minimize the coefficient of static liquid friction. Using a liquid version of Young’s law, I show low friction uni-directional and bi-directional droplet motion on liquid-infused surfaces. I also show surfaces with liquid-like solid coatings which overcome the risk of lubricant depletion and provide excellent anti-biofilm properties.
• [03590] Drop movement on lubricant-impregnated random textures
  • Format : Talk at Waseda University
  • Author(s) :
    • Ratan Bharat Ahuja (Indian Institute of Technology Bombay)
    • Amit Agrawal (Indian Institute of Technology Bombay)
    • Suhas S Joshi (Indian Institute of Technology Indore)
  • Abstract : Lubricant-impregnated surfaces (LIS), owing to their omniphobicity have shown remarkable success against Newtonian, non-Newtonian and yield stress fluids. These surfaces are, however, prone to failure due to lubricant drainage. In this work, we fabricate random textures using the micro-EDM process in an attempt to prolong lubricant retention within grooves. Drop motion and velocity against lubricant of three different viscosities are captured using digital imaging. The results would aid in designing a robust LIS system.
• [05601] Asymptotic solutions for convection in longitudinal-fin heat sinks
  • Format : Talk at Waseda University
  • Author(s) :
    • Toby Kirk (Imperial College London)
    • Marc Hodes (Tufts University)
  • Abstract : We consider forced convection in a longitudinal-fin heat sink, i.e. a periodic array of thin, thermally conducting fins aligned with the direction of air flow. Sparrow, Baliga and Patankar (1978) solved this problem numerically, investigating the effect of the gap between the fin tips and the shroud. We solve the same problem in the realistic asymptotic limit of small fin spacing, and make connections to similar mathematical problems for liquid flow over superhydrophobic grooved surfaces.
• [02837] Inertial effects on the flow resistance of axial-groove heat pipes
  • Format : Talk at Waseda University
  • Author(s) :
    • Haotian Jia (Tufts Univeristy)
    • Marc Hodes (Tufts University)
    • Toby Kirk (Imperial College London)
  • Abstract : We captured the effects of slowly-varying meniscus curvature on the flow resistance of the adiabatic section of an axial-groove heat pipe in the presence of inertial effects due to the changes in the cross-sectional areas of the liquid and vapor phases along the adiabatic section. This was by done by extending a hybrid analytical-numerical method for a single-phase problem with slowly-varying meniscus curvature to two-phase.

MS [00037] Recent advances in modelling and simulation of interfacial flows

room : D402

• [05355] On the transition to dripping of an inverted liquid film
  • Format : Talk at Waseda University
  • Author(s) :
    • Mark Blyth (University of East Anglia)
    • Dmitri Tseluiko (Loughborough)
    • Te-Sheng Lin (National Yang Ming Chiao Tung University)
  • Abstract : We discuss the transition to dripping in the gravity-driven motion of a liquid film under an inclined plate. Attention is focused on calculating travelling-wave solutions, for fixed fluid volume and fixed flow rate, using model lubrication equations and the full Stokes equations, and tracking the travelling-wave solution branch as the inclination angle of the plate is increased. Where the branch reaches a turning point we posit that the onset to dripping occurs.
• [03447] Influence of an elastic sheet on impact on a liquid surface
  • Format : Talk at Waseda University
  • Author(s) :
    • Doireann O'Kiely (MACSI, University of Limerick)
    • Finn Box (University of Manchester)
    • Ousmane Kodio (MIT)
    • Dominic Vella (University of Oxford)
  • Abstract : Impact at a liquid-air interface changes when an elastic sheet floats on the liquid surface. A ripple propagates out from the point of impact, but has a wavefront $r_m \sim t^{1/2}$ rather than the $r_m \sim t^{2/3}$ typical of capillary waves. We discuss the behaviour of the ``elastocapillary ripple’’, and reduce this new impact problem to a one-parameter similarity problem which interpolates between the limits of a point impactor and Wagner theory.
• [03420] Spin Coating on a Non-Axisymmetric Curved Substrate
  • Format : Talk at Waseda University
  • Author(s) :
    • Ross Geoffrey Shepherd (University of Cambridge)
    • Edouard Boujo (Ecole Polytechnique Federale de Lausanne)
    • Mathieu Sellier (University of Canterbury)
  • Abstract : Spin coating is used to apply functional coatings to flat substrates in the manufacturing of a range of electronic and optical components. Here, we develop a generalised model for the flow of a spin-coated film over an arbitrary substrate geometry, incorporating gravitational, surface tension, centrifugal, and Coriolis forces. In particular, we demonstrate the effects of the Coriolis force on the formation of fingering instabilities and the flow during the early stages of spin coating.
• [05432] Evaporation and the coffee-ring effect for non-circular droplets
  • Format : Online Talk on Zoom
  • Author(s) :
    • Madeleine Moore (University of Hull)
    • Alexander Wray (University of Strathclyde)
  • Abstract : Diffusion-limited evaporation of liquid droplets is commonplace in industrial applications such as microscale patterning and Q/OLED production. However, beyond simple geometries, there are few analytical solutions. Here, we derive asymptotic results for the evaporative flux of a weakly non-circular droplet and demonstrate how these may be used to find the ‘coffee ring’ for large droplets, with excellent agreement to numerical simulations. Then, we show how the mathematical framework may be extended to polygonal drops.

MS [00280] Canonical Scattering Theory and Application

room : D403

• [03187] Spectral computations for defect scattering in disordered topological insulators
  • Format : Talk at Waseda University
  • Author(s) :
    • Andrew Horning (Massachusetts Institute of Technology)
    • Matthew Colbrook (University of Cambridge)
    • Kyle Thicke (Texas A&M University)
    • Alex Watson (University of Minnesota)
  • Abstract : Topological insulators (TIs) support remarkable electronic wave phenomena that persist even in the presence of material defects and disorder. However, these phenomena are governed by an infinite-dimensional Hamiltonian with exotic spectral properties, which has frustrated the development of rigorous computational methods for disordered TIs. We use recent advances in computational spectral theory to rigorously and efficiently calculate conductivities and the generalized eigenstates that mediate interfacial electronic transport in two-dimensional TIs.
• [02368] Analysis of oversampled collocation methods for wave scattering problems
  • Format : Talk at Waseda University
  • Author(s) :
    • Georg Maierhofer (Sorbonne Université)
  • Abstract : In this talk, we will explore the extent to which the convergence properties of collocation methods for Fredholm integral equations can be improved by least-squares oversampling. We provide rigorous analysis to show that superlinear oversampling can enhance the convergence rates of the collocation method and reduce its sensitivity to the distribution of collocation points. We support our analysis with several numerical examples for the two-dimensional Helmholtz equation. This is joint work with Daan Huybrechs.
• [03067] Revisiting the frozen-gust assumption for edge scattering using spatially-varying wavepackets
  • Format : Talk at Waseda University
  • Author(s) :
    • Sonya Tiomkin (Lehigh University)
    • Justin Jaworski (Lehigh University)
  • Abstract : An analytic solution for the noise generated by a wavepacket traveling near the edge of a rigid semi-infinite flat plate is determined in closed form in the time domain. The spatially-varying wavepacket constitutes a surrogate model for turbulent flow distortions engendered by the edge geometry. This approach permits a relaxation of the common frozen gust assumption for trailing-edge noise prediction, whereby the local vorticity is assumed to be unaffected by the edge.
• [03239] Green's function for wave scattering by a semi-inifinite flat plate with a serrated edge
  • Format : Talk at Waseda University
  • Author(s) :
    • Benshuai Lyu (Peking University)
  • Abstract : An analytical Green’s function is developed to study the wave scattering by a semi-infinite flat plate with a serrated edge. The scattered pressure is solved using the Wiener-Hopf technique in conjunction with the adjoint technique. The kernel decomposition can be performed analytically in the high-frequency regime, which yields closed-form analytical Green's functions for any arbitrary piecewise linear serrations. The Green's function is shown to agree well with Finite Element Method (FEM) computations at high frequencies.

MS [00372] Recent advances on computational wave propagation

room : D404

• [02077] Harnessing the Power of Exascale Computing for Microelectronics Modeling
  • Format : Talk at Waseda University
  • Author(s) :
    • Zhi Jackie Yao (Lawrence Berkeley National Lab)
    • Revathi Jambunathan (Lawrence Berkeley National Lab)
    • Andy Nonaka (Lawrence Berkeley National Lab)
    • Prabhat Kumar (Lawrence Berkeley National Lab)
    • Saurabh Sawant (Lawrence Berkeley National Lab)
  • Abstract : As the era of Moore's law comes to a close, there has been a surge in the development of microdevices that involve more complex physical interactions than conventional electromagnetic waves and single-phase materials. However, gaining a deeper understanding of these interactions has been hindered by the significant disparity in time and length scales and a lack of effective modeling techniques. To address these challenges, we have developed ARTEMIS, a scalable simulation tool that harnesses the power of GPU-based supercomputing systems to model next-generation microelectronic devices, including electronic, spintronic, superconducting, and ferroelectric systems. ARTEMIS leverages the developments of two Exascale Computing Projects and supports dispersive material properties, user-defined excitations and boundary conditions, and heterogeneous physical coupling. Specifically, with its micromagnetics module, ARTEMIS is suitable for nonlinear spintronic applications and can be used as a device-level design and optimization tool. This new approach also provides a path to understanding and developing fully integrated electronic systems that go beyond the capabilities of traditional semiconductor technologies. ARTEMIS will enable a broader exploitation of new materials and provide new mechanisms for everything from low-power computing to high-efficiency microwave components, contributing to the development of next-generation architectures.
• [02080] Simulating Time Domain Electromagnetic Waves on a Differentiable Programming Platform
  • Format : Talk at Waseda University
  • Author(s) :
    • Yanyan Hu (University of Houston)
    • Yuchen Jin (University of Houston)
    • Xuqing Wu (University of Houston)
    • Jiefu Chen (University of Houston)
  • Abstract : A trainable theory-guided recurrent neural network (RNN) equivalent to finite-difference-time-domain (FDTD) method is designed to formulate electromagnetic propagation, solve Maxwell’s equations, and the inverse problem on differentiable programming platform PyTorch. For forward modeling, the computation efficiency is substantially improved. The inverse problem can be solved by setting the trainable weights of RNN as the material-related parameters and network training. Numerical results demonstrate the effectiveness and efficiency of the method for forward and inverse electromagnetic modeling.
• [02117] Iterative two-level algorithm for nonsymmetric or indefinite problems
  • Format : Talk at Waseda University
  • Author(s) :
    • Ming Tang (South China Normal University)
    • Xiaoqing Xing (South China Normal University)
    • Ying Yang (Guilin University of Electronic Technology)
    • Liuqiang Zhong (South China Normal University)
  • Abstract : In this talk, some new iterative two-level algorithms are designed and analyzed for solving the finite element discretization for nonsymmetric or indefinite elliptic/Maxwell problems. The two-level methods use only the same coarse spaces as the traditional two- grid algorithm, but its “fine spaces” use the higher order finite element space under the coarse grid. Therefore, the iterative two-level algorithm only need one grid and achieve the same convergence order of the traditional two-grid algorithms. At last. Numerical experiments are implemented to support the theoretical results, especially, the computational cost of two-level algorithms are lower to achieve the same convergence order for traditional two-grid algorithms.
• [01863] Analysis and application of FEMs for Ziolkowski's PML model
  • Format : Talk at Waseda University
  • Author(s) :
    • Li Zhu (Portland State University)
    • Jichun Li (University of Nevada Las Vegas)
  • Abstract : Perfectly Matched Layer PML technique is an effective tool proposed by Berenger to solve a wave propagation problem in unbounded domain without reflections. Here we are interested in the Ziolkowski PML reformulated in an integro-differential form, We introduce two novel FEMs for solving this equivalent PML model. Stability and convergence analysis are established for both schemes. Numerical results are presented to support our analysis and demonstrate the wave absorption effectiveness of this PML.

MS [00789] Algorithmic advances in computational quantum mechanics

room : D405

• [03564] Density functional theories: reformulations and regularizations
  • Format : Talk at Waseda University
  • Author(s) :
    • Michael Ruggenthaler (Max-Planck Institute for the Structure and Dynamics of Matter)
  • Abstract : Density functional theories try to reformulate quantum theories in terms of a set of reduced quantities, turning high-dimensional linear problems into low-dimensional but non-linear problems (1,2,3). In this talk I will give a short overview of open mathematical problems in density functional theories and provide potential solution strategies, either by Moreau-Yosida regularization (4) or by reformulating the the basic mappings (2,3). (1) Ruggenthaler, M., Penz, M., & Van Leeuwen, R. (2015). Existence, uniqueness, and construction of the density-potential mapping in time-dependent density-functional theory. Journal of Physics: Condensed Matter, 27(20), 203202. (2) Penz, M., Tellgren, E. I., Csirik, M. A., Ruggenthaler, M., & Laestadius, A. (2022). The structure of the density-potential mapping. Part I: Standard density-functional theory. arXiv preprint arXiv:2211.16627. (3) Penz, M., Tellgren, E.I., Csirik, M.A., Ruggenthaler, M, & Laestadius, A (2023). The structure of the density-potential mapping. Part II: Including magnetic fields. arXiv preprint arXiv:2303.01357 (4) Penz, M., Laestadius, A., Tellgren, E. I., & Ruggenthaler, M. (2019). Guaranteed convergence of a regularized Kohn-Sham iteration in finite dimensions. Physical Review Letters, 123(3), 037401.
• [04839] Fine-grained parallelism is flow-based Monte Carlo algorithms
  • Format : Talk at Waseda University
  • Author(s) :
    • Michael Samuel Albergo (New York University)
    • Michael S Albergo (New York University)
  • Abstract : Transport-based generative models have become an active topic of inquiry in scientific computing and Monte Carlo-based numerical methods, with demonstrated applications ranging from lattice quantum field theory to molecular systems. In this will talk, I will discuss the flow-based Monte Carlo approach and present some results related to taking advantage of its embarrassingly parallel setup.
• [04906] An unambiguous and robust formulation for Wannier localization
  • Format : Talk at Waseda University
  • Author(s) :
    • Kangbo Li (Cornell University)
  • Abstract : We provide a new variational definition for the spread of an orbital under periodic boundary conditions (PBCs) that is continuous with respect to the gauge, well-suited to diffuse orbitals, and can be adapted for schemes to compute localized Wannier functions. Existing definitions do not satisfy all these desiderata, partly because they depend on an "orbital center''---an ill-defined concept under PBCs. Moreover, we illustrate a more robust and efficient ($10\times$$-$$70\times$ fewer iterations) localization scheme.

contributed talk: CT156

room : D407

[02055] EMinv software platform for comprehensive analysis of geoscience data

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @D407
• Type : Contributed Talk
• Abstract : We designed and developed a new software platform, consisting of processing and inversion modular for magnetotelluric data and visualization modular for all the geoscience results. New self-improved processing and inversion algorithms were applied in this platform. This platform unified the format of data, results and models and connected data processing, interpretaion and visualization, using our new rule and integrated standard. The platform is a useful tool for both production managers and scientific researchers.
• Classification : 86-04, 86-02
• Format : Talk at Waseda University
• Author(s) :
  • Kun Zhang (Chinese Academy of Geopogical Sciences)

[00240] Phantom cosmological model with observational constraints in symmetric teleparallel gravity

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @D407
• Type : Contributed Talk
• Abstract : The cosmological model of the Universe has been presented in symmetric teleparallel gravity and the parameters are constrained from the cosmological datasets. The nonmetricity function considered here contains higher power of the nonmetricity. With some algebraic manipulation the Hubble parameter has been obtained in redshift. The cosmological and geometrical parameters are obtained and constrained using the recent Hubble and Pantheon + SHOES datasets. The model shows early deceleration and late time acceleration.
• Classification : 83C15, 83D05, 83C10, Modified Gravity, Cosmological Model.
• Author(s) :
  • Bivudutta Mishra (BITS-Pilani, Hyderabad Campus)

[00043] Matter-chameleon coupling in reconstructed Brans-Dicke cosmology

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @D407
• Type : Contributed Talk
• Abstract : In the present work, we studied the generalized Brans-Dicke (BD) model with a scalar field non-minimally coupled with the matter sector. We considered extended holographic Ricci dark energy $\rho_{\Lambda}=3\phi (\alpha\dot{H}+\beta H^2)$ in this BD cosmology framework, derived restrictions for BD parameter $\omega$, and observed a stronger matter-chameleon coupling. The EoS parameter behaved like quintom. We observed an increasing potential function as matter-chameleon coupling gets stronger. Also, deceleration parameter transited from decelerated to the accelerated universe phase.
• Classification : 83F05, 83C56
• Format : Online Talk on Zoom
• Author(s) :
  • Surajit Chattopadhyay (Amity University, Kolkata)

MS [01622] Mathematics for Prediction and Control of Complex Systems

room : D408

• [02789] Identifying Coherent Structures within Turbulent Flows over Roughness Obstacles
  • Format : Talk at Waseda University
  • Author(s) :
    • Tetsuya Takemi (Kyoto University)
  • Abstract : Large-eddy simulations for turbulent flows over roughness obstacles are conducted to investigate the characteristics of coherent structures within turbulent flows for a possible application for controlling flow structures in urban districts. Idealized and realistic urban districts are examined as rough surfaces. Turbulence and dispersion properties associated with coherent structures are demonstrated. Understanding such properties will lead to identify an approach to control flows within urban districts.
• [02825] Quantifying Weather Controllability and Mitigatable Flood Damage Based on Ensemble Weather Forecast
  • Format : Talk at Waseda University
  • Author(s) :
    • Shunji Kotsuki (Chiba University)
  • Abstract : For realizing a weather-controlled society, we need to discuss the way to maximize the effect of manipulations to the atmosphere. For that purpose, this project aims at developing methods that quantify weather controllability and mitigatable flood damage based on ensemble weather forecasts. To quantify weather controllability, this project investigates meteorological landscapes that separate disaster and non-disaster regimes which may be controllable with small manipulations. We also estimate economic damages under non-controlled/controlled scenarios, in order to quantify avoidable damage by weather control. We have started illustrating directed graphs as the first step in understanding the meteorological landscape. Typhoon Prapiroon in 2018 was used for the case study. Singular value decomposition (SVD) is employed for Japan Meteorological Agency’s operational meso-scale ensemble prediction data to extract principle components of atmospheric states, followed by a clustering using density-based spatial clustering of applications with noise known as DBSCAN. The illustrated graph succeeded in detecting separated two clusters that correspond to faster and slower movements of predicted Parapiroon. The developed algorithm is currently applied to other disastrous events as well as further investigations on non-linear data compression methods beyond SVD. This presentation includes the most recent achievements up to the time of the conference.
• [02885] Ensemble sensitivity and its potential applications in weather control
  • Author(s) :
    • Le Duc (University of Tokyo)
    • Yohei Sawada (University of Tokyo)
  • Abstract : Ensemble sensitivity has been proved to be a very useful sensitivity measure in practice. In this study, we show the relevance of ensemble sensitivity in another important problem. We have proved that changes of the forecast response are maximized along the direction of the vector consisting of ensemble sensitivities which forms the most sensitive perturbation. We will demonstrate how the new understanding on ensemble sensitivities can qualitatively give potential solutions for weather control.
• [02518] Chaos implies effective controllability of extreme weather
  • Format : Talk at Waseda University
  • Author(s) :
    • Takemasa Miyoshi (RIKEN)
    • Qiwen Sun (RIKEN)
    • Koji Terasaki (RIKEN)
    • Yasumitsu Maejima (RIKEN)
  • Abstract : Since the weather system is chaotic, and even more so for storms, small differences generally lead to big differences, particularly for high-impact weather events. This presentation will summarize the concept and methodology of Control Simulation Experiment (CSE) with some proof-of-concept demonstrations with toy models and realistic Numerical Weather Prediction (NWP) models. This is an attempt to a potential paradigm change of NWP research from decades of predictability to the new era of controllability.

MS [01718] On SDP relaxations of polynomial optimization

room : D501

contributed talk: CT160

room : D502

[02661] Practicing Responsible Computation and Innovation in HPC: A Sociotechnical Approach

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @D502
• Type : Industrial Contributed Talk
• Abstract : Recent advances in high performance computing (HPC) and artificial intelligence (AI) have reignited discussions for more responsible and ethical computing regarding the use and design of HPC sociotechnical ecosystems within the context of cultures and evolving societal norms. This contributed talk provides practical guidelines derived from computational and social science that scientists, educators, and practitioners alike can employ to become more aware of personal values that may unconsciously shape approaches to computation and ethics.
• Classification : 91C99, 68-01, 68-04, 68N01, ethics, sociotechnical approach, responsible computing
• Format : Talk at Waseda University
• Author(s) :
  • Elaine M. Raybourn (Sandia National Laboratories)
  • Osni Marques (Lawrence Berkeley National Laboratory)
  • Killian Muollo (Sandia National Laboratories)

[00301] On some modifications in the conjugate gradient method and its application in unconstrained optimization problems

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @D502
• Type : Contributed Talk
• Abstract : Conjugate gradient (CG) methods are preferably used to solve large-scale unconstrained optimization problems due to strong local and global convergence properties and low memory requirements. To enhanse its convergence, we introduce an improved hybrid form of the conjugate gradient method in this work. We propose a new form of CG parameter (βk), combining the Fletcher Reeves (FR) and three-term search directions. Our proposed search directions formula satisfies the sufficient descent condition independent of any line search and are bounded. For the global convergence, some proper assumptions on the objective function and its gradient have been taken into account, which fulfills the strong Wolfe-Powell line search conditions. Finally, numerical experiments have been carried out on some standard benchmark test functions and compared with other CG methods from the literature to check the validity of the proposed algorithm. Numerical results guarantee the efficiency and robustness of our proposed CG method.
• Classification : 90-XX, 90C26, 90C30, 90bxx, 90-08
• Format : Online Talk on Zoom
• Author(s) :
  • Sweta Kumari (Birla Institute of Technology Mesra, Ranchi)
  • Darakhshan Jabeen Syeda (Birla Institute of Technology Mesra, Ranchi)

[01303] Partially Mixed Cooperative Strategies in Evolutionary Games on Networks

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @D502
• Type : Contributed Talk
• Abstract : Cooperation is fundamental for the development of human societies. Different approaches have been proposed to explain the emergence of cooperation or partial cooperation in populations of individuals playing classical types of games. In this talk, we analyze the emergence of a new kind of cooperation, where we have a set of full cooperators and one of the partial ones, for the classical games. We prove conditions for Nash equilibria to be asymptotically stable.
• Classification : 91CXX
• Format : Online Talk on Zoom
• Author(s) :
  • Jean Carlo Moraes (Universidade Federal do Rio Grande do Sul)

[02381] Dynamic parking pricing for smart urban transportation system

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @D502
• Type : Contributed Talk
• Abstract : Traffic jam is one of the critical challenges of an urban city. Researchers have reported that search for a parking space significantly contributes to this problem. By having a dynamic pricing depending on the demand, this challenge can partially be addressed by filtering customers to move to other non-demanding parking spaces or look for cost reasonable options. Furthermore, parking places will compete to maximize their profit. Hence, a game theoretic or hierarchical decision making model can best describe the scenario. Bounded by the allowed maximum parking pricing, perhaps set by the city administration, and the minimum price to stay in business, this paper models a dynamic parking pricing as a price-wise continuous multilevel decision making problem.
• Classification : 90-XX, 90B06, 00A69
• Author(s) :
  • Surafel L Tilahun (Addis Ababa Science and Technology University)

[01102] Independent Study in Designing Mathematics Learning Using GeoGebra AR

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @D502
• Type : Industrial Contributed Talk
• Abstract : This research examines the implementation of one program from the Indonesian Ministry of Education, Culture, Research, and Technology, i.e., independent studies, in the Department of Mathematics Education at a public university in Langsa, Aceh, Indonesia. The activities focused on compiling learning designs that apply the GeoGebra Augmented Reality (AR) to geometrical concepts in secondary schools by adopting the ADDIE Model. The aim is for pre-service mathematics teachers to explore learning activities independently in mastering Technological Pedagogical Content Knowledge (TPACK) when teaching mathematics. Our findings suggest the implementation of such an independent study because of its advantages and program improvisation as a form of program development.
• Classification : 97Gxx, 97Hxx, 97Uxx
• Format : Online Talk on Zoom
• Author(s) :
  • Guntur Maulana Muhammad (Universitas Samudra)
  • Natanael Karjanto (Sungkyunkwan University)
  • Iden Rainal Ihsan (Universitas Samudra)

contributed talk: CT162

room : D505

[02418] A two-stage method for an industrial NP-hard bin packing problem

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @D505
• Type : Industrial Contributed Talk
• Abstract : Our industrial problem consists of building batch annealings from a sample of steel coils. We have to consider all the rules/constraints related to the characteristics of coils and constraints related to technology. The objective is to ensure the annealing of coils at the minimum cost. This problem is a simultaneous NP-hard bin packing type. A two-stage method is developed in this paper to address this problem: stage one refers to a smart enumeration of all possible and feasible bins. Then, the second stage will consist of finding the optimal solution for an ILP.
• Classification : 90B30, 90C10
• Format : Talk at Waseda University
• Author(s) :
  • Abdelghani Bouras (Industrial Engineering Department, College of Engineering, Al lFaisalUniversity)

[01418] Non-linear Particle Swarm Optimization Algorithm for Non-linear Fixed-charge Transportation Problems

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @D505
• Type : Industrial Contributed Talk
• Abstract : The non-linear fixed-charge transportation problems are one of the challenging NP-hard problems. Hence, a new non-linear particle swarm optimization algorithm (NPSO) with new inertia weight and acceleration coefficients have been introduced that not only explores the search space but also maintains the feasibility condition of the transportation problem. The performance of the proposed NPSO is compared with its existing variants. Also, some benchmarks problems from the literature have been solved and the results are compared.
• Classification : 90B06, 90C30, 90C90, 90C06
• Format : Talk at Waseda University
• Author(s) :
  • Shivani Saini (Dr B R Ambedkar National Institute of Technology Jalandhar (INDIA))
  • Deepika Rani (Dr B R Ambedkar National Institute of Technology Jalandhar (INDIA))

[02269] Mathematical model for prioritize patient in operating room block scheduling

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @D505
• Type : Contributed Talk
• Abstract : We concentrate on the scheduling problem in surgical operating room that involves limited equipment and surgical specialities. Our objective is develop a feasible schedule that consider resources utilization, prioritized patients in health risk condition and availability of the surgical specialities teams. Our approach is the assignation of operating room by block using week horizon with different relative weight. A mathematical model is proposed to optimum the operating room scheduling performance.
• Classification : 90B35
• Format : Online Talk on Zoom
• Author(s) :
  • Syarifah Zyurina Nordin (Malaysia Japan International Institute of Technology (MJIIT), Universiti Teknologi Malaysia)

[02457] Optimizing Bunkering Management Strategy to Support Green Shipping Using Artificial Bee Colony Algorithm (ABC)

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @D505
• Type : Contributed Talk
• Abstract : Sea transportation has been considered as more eco-friendly transportation compared to other transportation. However, maritime logistic has produced a lot of carbon emissions. Therefore, this research is performed for optimizing the development of bunkering management strategies. It will focus on choosing a fuel with an affordable price and producing fewer carbon emissions. The problem can be formulated as the MINLP to minimize the total cost and can be solved by ABC algorithm as an optimization method.
• Classification : 90Bxx, 90Cxx, 90-08
• Format : Online Talk on Zoom
• Author(s) :
  • Nurul Fajr Romadhona (Sepuluh Nopember Institute of Technology)
  • Sena Safarina (Sepuluh Nopember Institute of Technology)
  • Oktaviani Turbaningsih (University of Tasmania)

[01358] Compartment Models for Ideas on Social Media Networks

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @D505
• Type : Contributed Talk
• Abstract : The concept of virality and the structure of social media networks lend themselves to the use of SIR-like compartment models to study the spread of ideas between users on these platforms. This talk introduces the USBA - Unexposed, Sending, Bored, and Acclimated - family of discrete compartment models as a means of simulating how ideas reach and affect users and change the network structure, leading to the formation of echo chambers and polarization in sentiment.
• Classification : 91D30, 91D10, 34C60, Internet Studies
• Format : Online Talk on Zoom
• Author(s) :
  • Adam Mark Furman (University of Oxford Mathematical Institute)

contributed talk: CT172

room : D514

[01973] Equilibria for Robust Routing Game of Atomic Players

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @D514
• Type : Contributed Talk
• Abstract : We study a routing game on edge costs given by an interval of the same length, each edge cost can be any value in the interval. Each player only knows the interval length and would select a path that is robust against the worst-case realization of edge costs. Under bottleneck-type objective with minmax-regret criterion, we prove that every robust Nash Equilibrium (NE) is an NE of the corresponding bottleneck routing game with complete information.
• Classification : 91A35, 91A80, 91A68, 90C27
• Format : Talk at Waseda University
• Author(s) :
  • Xudong Hu (Academy of Math and Systems Science, CAS)

[00383] A kernel-based method for Schrödinger bridges

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @D514
• Type : Contributed Talk
• Abstract : We propose a kernel-based machine learning method for numerical solutions of Schrödinger's bridge problems. In this method, the terminal time distribution constraint is described by a kernel-based metric on the space of probability measures.
• Classification : 93E20
• Format : Talk at Waseda University
• Author(s) :
  • Yumiharu Nakano (Tokyo Institute of Technology)

[01075] Implementation of Mathematical Proof and Argumentation Learning Activities in Langsa

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @D514
• Type : Industrial Contributed Talk
• Abstract : This study aims to implement learning designs for mastering mathematical proof and argumentation abilities in pre-service mathematics teachers enrolling in one public university in Langsa City, Aceh, Indonesia. Learning activities consist of four core stages, i.e., proofreading, writing resumes, exercises in proving, then reflection and evaluation. The results demonstrated an increase in students' mathematical proof and argumentation abilities from mediocre to excellent.
• Classification : 97Dxx, 97Hxx, 97Ixx, 97Exx
• Format : Talk at Waseda University
• Author(s) :
  • Iden Rainal Ihsan (Universitas Samudra)
  • Natanael Karjanto (Sungkyunkwan University)
  • Guntur Maulana Muhammad (Universitas Samudra)

[00601] Assessment of Mathematics in Higher Education over the COVID19 pandemic.

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @D514
• Type : Industrial Contributed Talk
• Abstract : A comparative analysis of various assessment methods on Higher Education Mathematics is provided. A discussion on the reliability of these methods is provided with particular emphasis on distance/online (uncontrolled) assessment methods and face to face (controlled) assessment methods. We analyse the data collected from an assessment strategy based on a set of tests before and throughout the COVID pandemic. Results show that online assessment is less reliable for those students with lower academic performance.
• Classification : 97D60, Assessment of Mathematics in Higher Education
• Format : Talk at Waseda University
• Author(s) :
  • Carlos Fresneda-Portillo (Universidad Loyola Andalucía (Spain))
  • James Maunder (Oxford Brookes University)

MS [00509] Recent developments in stochastic optimization

room : A201

• [00650] Random activations in primal-dual splittings for monotone inclusions with a priori information
  • Format : Talk at Waseda University
  • Author(s) :
    • Luis Briceño-Arias (Universidad Técnica Federico Santa María)
  • Abstract : In this paper, we propose a numerical approach for solving composite primal-dual monotone inclusions with a priori information. The underlying a priori information set is represented by the intersection of fixed point sets of a finite number of operators, and we propose an algorithm that activates the corresponding set by following a finite-valued random variable at each iteration. Our formulation is flexible and includes, for instance, deterministic and Bernoulli activations over cyclic schemes, and Kaczmarz-type random activations. The almost sure convergence of the algorithm is obtained by means of properties of stochastic Quasi-Fejér sequences. We also recover several primal-dual algorithms for monotone inclusions without a priori information and classical algorithms for solving convex feasibility problems and linear systems. In the context of convex optimization with inequality constraints, any selection of the constraints defines the a priori information set, in which case the operators involved are simply projections onto half spaces. By incorporating random projections onto a selection of the constraints to classical primal-dual schemes, we obtain faster algorithms as we illustrate by means of a numerical application to a stochastic arc capacity expansion problem in a transport network.
• [01376] New results on Carathéodory integral functions, applications to stochastic optimization
  • Format : Talk at Waseda University
  • Author(s) :
    • Minh Nhut Bui (Universität Graz)
    • Patrick L. Combettes (North Carolina State University)
  • Abstract : We present new results on Carath\'eodory integral functions and discuss applications to stochastic optimization.
• [03790] Adaptive partition-based method for 2-stage stochastic linear programming
  • Format : Talk at Waseda University
  • Author(s) :
    • Eduardo Moreno (Universidad Adolfo Ibañez)
    • Ivana Ljubic (ESSEC Business School)
  • Abstract : The Generalized Adaptive partition-based method for solving 2-stage stochastic linear problems is based on iteratively and automatically aggregating the uncertainty space into scenarios and disaggregating them based on the dual subproblem variables. It can be seen as a Benders-like method, where optimality cuts are adaptively aggregated based on the dual solutions. Computational experiments show significant improvements compared to classical methods, including the possibility of solving problems in continuous probability spaces using discrete optimization.
• [03978] Multistage optimization of a partially observed petroleum production system
  • Format : Talk at Waseda University
  • Author(s) :
    • Jean-Philippe Chancelier (CERMICS -- Ecole des Ponts ParisTech)
    • Pierre Carpentier (UMA, ENSTA PARIS)
    • Michel De Lara (CERMICS - Ecole des Ponts ParisTech)
    • Cyrille Vessaire (CERMICS -- Ecole des Ponts ParisTech)
    • Alejandro Rodriguez-Martinez (Total Energies, SE Pau)
  • Abstract : An oil production network is composed of one or more reservoirs (geological formations containing oil) connected through a network of wells and pipes. At the beginning of the reservoir exploitation, we have only partial knowledge of the content of the reservoir, namely a probability distribution of the initial state of the reservoir. We propose a formulation of the management of an oil production network where the reservoir is a partially observed controlled dynamical system. This approach leads to a well-known class of problems: Partially Observed Markovian Decision Process (POMDP). However, general POMDPs are often untractable due to the curse of dimensionality. In the case of the proposed formulation, we consider a subclass of POMDPs: deterministic-POMDPs (deterministic transition and observation). We highlight and exploit structure in the deterministic-POMDP formulation to push back the curse of dimensionality. Then, we are able to use Dynamic Programming to find the optimal production planning. Finally, we present numerical applications.

MS [00521] Recent advances on non-convex optimization in inverse problems, imaging and machine learning

room : A206

• [01258] Global convergence of the gradient method for functions definable in o-minimal structures
  • Format : Talk at Waseda University
  • Author(s) :
    • Cedric Josz (Columbia University)
  • Abstract : We consider the gradient method with variable step size for minimizing functions that are definable in o-minimal structures on the real field and differentiable with locally Lipschitz gradients. A sufficient condition ensuring global convergence is discussed, with implications for the convergence rate and convergence to a local minimum. Applications include principal component analysis, matrix sensing, and linear neural networks.
• [04681] Convergence theory for mean-field optimization methods
  • Format : Talk at Waseda University
  • Author(s) :
    • Atsushi Nitanda (Kyushu Institute of Technology)
    • Denny Wu (University of Toronto)
    • Taiji Suzuki (The University of Tokyo)
  • Abstract : Optimization of mean-field models recently attracts attention due to its connection to training two-layer neural networks under the mean-field regime. To analyze the optimization dynamics of mean-field models, we have established the theory of convex analysis and have derived several optimization methods. In this talk, we present recent advances in the theory for mean-field optimization methods.
• [03322] Convergence Theorem for Deep Neural Network with ReLU Activation
  • Format : Talk at Waseda University
  • Author(s) :
    • Gue Myung Lee (Department of Applied Mathematics, Pukyong National University)
    • Jae Hyoung Lee (Department of Applied Mathematics, Pukyong National University)
    • Kwang Baik Lee (Department of Applied Mathematics, Pukyong National University)
  • Abstract : Deep Neural Network (Deep Learning) is an artificial neural network which consists of input layer, output layer and many hidden layers between them. The gradient descent algorithm is the key one in the learning system for the deep neural network. So, for understanding the learning system, we should know the convergence for the descent algorithm for the cost function of L-layers neural network. The cost function is a composition of weight variables, biases variables and activation functions. In this talk, we consider the convergence theorem for the descent algorithm for the cost function of L-layers neural network with ReLU function(:$\sigma (z) = {\rm max} \{0, z\}$) as its activation function. First, we show that the cost function is semi-algebraic and locally Lipschitz. Secondly, we show that the sequence, which was generated by the descent algorithm with Clarke generalized gradient, globally converges to a stationary point (critical point) under certain assumptions. Thirdly, we prove that the set of critical values of the cost function is finite.
• [05068] Theoretical and practical applications of signomial rings to polynomial optimization
  • Format : Talk at Waseda University
  • Author(s) :
    • Mareike Dressler (UNSW Sydney)
  • Abstract : Signomials generalize polynomials by allowing arbitrary real exponents, at the expense of restricting the resulting function to the positive orthant. In this talk, I present a signomial Positivstellensatz based on conditional "sums of arithmetic-geometric exponentials" (SAGE). The Positivstellensatz applies to compact sets which need not be convex or even basic semi-algebraic. In the first part of the talk, I explain how this result is derived through the newly-defined concept of signomial rings. Then I show how the same concept leads to a novel convex relaxation hierarchy of lower bounds for signomial optimization. These relaxations (which are based on relative entropy programming) can be solved more reliably than those arising from earlier SAGE-based Positivstellensätze. Moreover, this increase in reliability comes at no apparent cost of longer solver runtimes or worse bounds. Numerical examples are provided to illustrate the performance of the hierarchy on a problem in chemical reaction networks. This talk is based on joint work with Riley Murray.

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

room : A207

MS [00027] Recent trends on crowd management

room : A208

• [05480] Crowd Management Platform as a Service
  • Format : Talk at Waseda University
  • Author(s) :
    • Katsuhiro Nishinari (The University of Tokyo)
  • Abstract : Crowd management is important for safety and efficient movement of individuals. The process involves sensing crowd conditions in real time, predicting the near future from that data, and then guiding the crowd through a risk assessment to prevent accidents before they happen. The platform supporting this series of functions is named Crowd Management Platform as a Service (CMPaaS).In the presentation, actual case studies using CMPaaS will be presented.
• [05405] 3D Visualization of Crowd Motion
  • Format : Online Talk on Zoom
  • Author(s) :
    • Kensuke Yasufuku (Osaka University)
  • Abstract : This presentation proposes methods for effective 3D visualization of crowd motion in large sites under both normal and emergency conditions. We utilize agent-based crowd simulations to model and predict behavioral patterns under various scenarios. These simulations serve as critical tools for predicting congestion within these sites and for evaluating and optimizing appropriate evacuation plans. Furthermore, we will discuss visualization techniques for sharing information among stakeholders.
• [05377] Numerical description of pedestrian crowds: are we really particles?
  • Format : Talk at Waseda University
  • Author(s) :
    • Claudio Feliciani (The University of Tokyo)
  • Abstract : Quantification of properties related to pedestrian crowds is necessary for analyzing pedestrian flows and automating real-time control. Often, models inspired by physics and fluid dynamics are used to describe crowds by simplifying people as particles. While these models often yield good results, they are typically only valid for specific conditions. This highlights the need to better understand the cognitive and psychological aspects of human motion in crowds to improve the quantification of pedestrian collective dynamics.
• [05404] Crowd management and visitors’ attitudes in natural recreational areas
  • Format : Talk at Waseda University
  • Author(s) :
    • Tetsuya Aikoh (Hokkaido University)
    • Hyerin Kim (Hokkaido University)
    • Yasushi Shoji (Hokkaido University)
  • Abstract : While outdoor recreation areas are expected to attract visitors, there are concerns about overtourism. Outdoor spaces without obvious entrances and exits present many sensing challenges. In addition, controlling crowding in public recreation areas requires consensus with visitors and local stakeholders. We will report on recent research findings and their contribution to management in World Heritage areas and urban greening events.

MS [02445] Advances in Optimization II

room : A502

• [03367] Two constructive techniques for producing linear extended formulations
  • Format : Talk at Waseda University
  • Author(s) :
    • Yuri Faenza (Columbia University)
  • Abstract : We will present two constructive techniques for producing extended formulations: one based on communication protocols, the other on Birkhoff's representation theorem for finite distributive lattices. We also show applications to some problems, mostly in combinatorial optimization.
• [03641] Interior-point methods on manifolds: theory and applications
  • Format : Talk at Waseda University
  • Author(s) :
    • Hiroshi Hirai (Nagoya University)
    • Harold Nieuwboer (University of Amsterdam)
    • Michael Walter (Ruhr University)
  • Abstract : We extend the theory of self-concordance for manifolds, and establish analogous results as in the Euclidean setting, such as quadratic convergence of Newton's method and polynomial iteration complexity of the path-following method. We show that on symmetric spaces of nonpositive curvature, the squared distance function to a point is self-concordant. These results are applied to norm minimization problems for reductive group actions, and to other geometric problems, such as minimum enclosing balls and geometric medians.
• [03069] Alternating Linear Minimization: Revisiting von Neumann’s alternating projections
  • Format : Talk at Waseda University
  • Author(s) :
    • Gábor Braun (ZIB)
    • Sebastian Pokutta (ZIB / TUB)
    • Robert Weismantel (ETH)
  • Abstract : In 1933 von Neumann proved a beautiful result that one can compute a point in the intersection of two convex sets (under suitable assumptions) by alternating projections, i.e., successively projecting on one set and then the other. This algorithm assumes that one has access to projection operators for both sets. Here we consider the much weaker setup where we have only access to linear minimization oracles over the convex sets and present an algorithm to find a point in the intersection of two convex sets. Moreover, we provide a modification of the algorithm to minimize a linear function over the intersection and discuss further extensions.
• [03052] Combinatorial and geometric aspects of linear optimization
  • Format : Talk at Waseda University
  • Author(s) :
    • Antoine Deza (McMaster University)
  • Abstract : Worst-case constructions have helped providing a deeper understanding of how the structural properties of the input affect the computational performance of linear optimization. Recent examples include the construction of Allamigeon et al. for which the interior point method performs an exponential number of iterations. In a similar spirit, recent lower bounds on the number of simplex pivots required in the worst-case to perform linear optimization over a lattice polytope are presented.

MS [00114] Computational Biology

room : A508

• [05357] Different mathematical models for membrane electroporation: from equivalent circuit to phase-field models
  • Format : Talk at Waseda University
  • Author(s) :
    • Clair Poignard (INRIA Center of Bordeaux Univ.)
  • Abstract : Electroporation is a complex phenomenon consisting of defects creation in membranes subjected to high short electric pulses. The aim of the talk is to present the mathematical challenges in terms of PDEs and numerical analysis of the phenomenon. A comparison from the 90’s biophysical models based on Deryagin theory to very recent phase-field model are performed. For each approach, advantages and disadvantages are discussed, in terms of physical meaning and validation with the experimental data.
• [02031] Modeling and characterizing vaccine-elicited antibody responses
  • Format : Talk at Waseda University
  • Author(s) :
    • Shingo Iwami (Nagoya University)
  • Abstract : Recent studies have provided insights into the effect of vaccine boosters on recall immunity. Given a limited global supply of the vaccinations, identifying vulnerable populations with lower sustained vaccine-elicited antibody titers is important to decide target individuals for the booster. Here we investigated longitudinal data among the cohort of the same individuals of 2,526 people in Fukushima, Japan. Antibody titers following a two-dose SARS-CoV-2 vaccination were repeatedly monitored along with the information on lifestyle habits, comorbidities, adverse reactions, and medication. By employing mathematical modeling and machine learning, we characterized the elicited immune response following a two-dose SARS-CoV-2 vaccination.
• [03370] Mathematical analysis of bone metabolism markers in immobilization mice
  • Format : Talk at Waseda University
  • Author(s) :
    • Marwa Akao (Nagoya University)
  • Abstract : Osteoporosis is a disease that affects more than 200 million people around the world. Although the mechanisms are gradually being revealed, osteoporosis cannot really be cured completely. This study aims to develop the most effective prevention for osteoporosis. We developed mathematical models describing interactions with cells related to bone metabolism and changes in bone mass. And we analyzed the data of bone metabolism markers and compared the difference between immobilization mice and normally fed mice.
• [02284] Predicting clinical outcomes of acute liver failure
  • Format : Online Talk on Zoom
  • Author(s) :
    • Raiki Yoshimura (Division of Natural Science, Graduate School of Science, Nagoya University)
  • Abstract : We used clinical data on acute liver failure to develop an approach for predicting its clinical outcomes. Specifically, we employed a supervised machine learning approach to analyze clinical datasets, including blood test data and medication history, at the admission to the hospital, and predicted final state, i.e., survived or died. In addition, we developed a scoring system to predict individual clinical outcomes. The findings of this study are expected to be utilized in actual clinical practice as a basis for initial response decisions and may also be applied to the detection of other signs of acute diseases.

MS [00437] Climate Risks: From Modelling to Applications

room : A510

• [01328] When Green Investors Are Green Consumers
  • Format : Talk at Waseda University
  • Author(s) :
    • Olivier David Zerbib (EDHEC)
    • Maxime Sauzet (Boston University)
  • Abstract : We introduce investors with preferences for green assets to a general equilibrium setting in which they also prefer consuming green goods. Their preference for green goods induces consumption premia on expected returns, which counterbalance the green premium stemming from their preferences for green assets. Because they provide a hedge when green goods become expensive, brown assets command lower consumption premia, while green investors allocate a larger share of their portfolios towards them. Empirically, the green-minus-brown consumption premia differential reached 30-40 basis points annually, and contributes to explaining the limited impact of green investing on the cost of capital of polluting firms.
• [01612] Bridging Shared Socioeconomic Pathways of GHG Emission and Credit Risk
  • Format : Talk at Waseda University
  • Author(s) :
    • Florian Bourgey (Bloomberg L.P.)
  • Abstract : We investigate the impact of transition risk on a firm’s low-carbon production. As the world is facing global climate change, the Intergovernmental Panel on Climate Change has set the idealized carbon-neutral scenario around 2050. In the meantime, many carbon reduction scenarios, known as Shared Socioeconomic Pathways (SSPs) have been proposed in the literature for different production sectors in a more comprehensive socio-economic context. We consider, on the one hand, a firm that aims to optimize its emission level under the double objectives of maximizing its production profit and respecting the emission mitigation scenarios. Solving the penalized optimization problem provides the optimal emission according to a given SSP benchmark. On the other hand, such transitions affect the firm’s credit risk. We model the default time by using the structural default approach. We are particularly concerned with how, by following different SSPs scenarios, the adopted strategies may influence the firm’s default probability. We then show how to incorporate physical risk and extend the previous framework to a large-sized portfolio.
• [01683] On some initial climate change impact models in actuarial science
  • Format : Online Talk on Zoom
  • Author(s) :
    • Stephane Loisel (ISFA, Universite Lyon 1)
  • Abstract : In this talk, we start by presenting the main sources of uncertainty about the impact of climate change in the insurance industry, and the approaches proposed to model them. We then focus on the impact of physical risk on biometric risks for life insurance and on claims frequency risk in non-life insurance and present work in progress on these two topics.
• [05370] Optimal carbon tax in the Golosov et al. 2014 DGSE central planning model
  • Format : Online Talk on Zoom
  • Author(s) :
    • Stéphane Crépey (Université Paris Cité / LPSM)
    • Dounia Essaket (Université Paris Cité / LPSM)
    • Florian Bourgey (Bloomberg L.P.)
    • Noufel Frokha (Université Paris 1)
    • Gauthier Vermandel (Ecole Poytechnique)
  • Abstract : We provide a full analytical solution to the Golosov et al. 2014 optimal control formulation of the carbon tax problem in a DGSE central planning setup. Whereas the original paper was only solving the problem in terms of first order necessary conditions, we derive the value function itself. This gives a direct access to the carbon tax as the derivative of the value function with respect to the Lagrangian parameter associated with the labor constraint.

contributed talk: CT179

room : A511

[01201] How differential geometry and extremum seeking systems reveal the decades- long mystery of optimized flight of soaring birds

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @A511
• Type : Contributed Talk
• Abstract : The optimized flight physics of soaring birds such as albatrosses have always been fascinating to biologists, physicists, mathematicians, and engineers. How can soaring birds fly in that effective way without spending almost any energy? The decades-long literature of the problem has not been successful in providing frameworks that can work in real time similar to the birds themselves. Recently, a breakthrough took place in providing a simple, real time extremum seeking method that characterizes this phenomenon and implements it in real time. Mathematical analysts using differential geometric methods have been successful in supporting these new results.
• Classification : 92-10, 93-10, 93B05, 53Z05
• Format : Talk at Waseda University
• Author(s) :
  • Sameh Eisa (University of Cincinnati )

[01644] Optimal epidemic interventions and the trolley problem in heterogeneous populations

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @A511
• Type : Contributed Talk
• Abstract : Interventions to mitigate the spread of infectious diseases, while succeeding in their goal, have economic and social costs associated with them; this limits the duration and intensity of the interventions. We study a class of interventions which reduce the reproduction number and find the optimal strength of the intervention which minimises the number of infections by eliminating the overshoot part of an epidemic, and avoiding a second-wave of infections. We extend the framework to a heterogeneous population and find that the optimal intervention can pose an ethical dilemma for decision and policy makers. This ethical dilemma is shown to be analogous to the trolley problem and we discuss how the problem may be avoided.
• Classification : 92-10, 34A34
• Format : Online Talk on Zoom
• Author(s) :
  • Pratyush Kumar Kollepara (La Trobe University)
  • Rebecca Chisholm (La Trobe University)
  • Istvan Kiss (University of Sussex)
  • Joel Miller (La Trobe University)

[00469] A Mathematical and Exploratory Data Analysis of Malaria Disease Transmission Through Blood Transfusion

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @A511
• Type : Contributed Talk
• Abstract : Malaria is a mosquito-borne disease spread by an infected vector (infected female Anopheles mosquito) or through transfusion of plasmodium-infected blood to susceptible individuals. The disease burden has resulted in high global mortality, particularly among children under the age of five. Many intervention responses have been implemented to control malaria disease transmission, including blood screening, Long-Lasting Insecticide Bed Nets (LLIN), treatment with an anti-malaria drug, spraying chemicals/pesticides on mosquito breeding sites, and indoor residual spray, among others. As a result, a SIR (Susceptible - Infected - Recovered) model is developed to study the impact of various malaria control and mitigation strategies. The associated basic reproduction number and stability theory is used to investigate the stability analysis of the model equilibrium points. The global stability of the malaria-free equilibrium is investigated by constructing an appropriate Lyapunov function. By determining the direction of bifurcation, the implicit function theorem is used to investigate the stability of the model endemic equilibrium. Using R and MATLAB, the model is fitted to malaria data from Benue State, Nigeria. Estimates of parameters were made. An optimal control model is then developed and analyzed using Pontryaging's Maximum Principle. The malaria-free equilibrium point is locally and globally stable if the basic reproduction number $(R_{0})$ and the blood transfusion reproduction number $(R_{\alpha})$ are both less or equal to unity. The study of the sensitive parameters of the model revealed that the transmission rate of malaria from mosquito-to-human $(\beta_{mh})$, transmission rate from humans-to-mosquito $(\beta_{hm})$, blood transfusion reproduction number $(R_{\alpha})$ and recruitment rate of mosquitoes $(b_{m})$ are all sensitive parameters capable of increasing the basic reproduction number $(R_{0})$ thereby increasing the risk in spreading malaria disease. The result of the optimal control shows that five possible controls are effective in reducing the transmission of malaria. The study recommended the combination of five controls, followed by the combination of four and three controls is effective in mitigating malaria transmission. The result of the optimal simulation also revealed that for communities or areas where resources are scarce, the combination of Long Lasting Insecticide Treated Bednets $(u_{2})$, Treatment $(u_{3})$, and Indoor insecticide spray $(u_{5})$ is recommended. Numerical simulations are performed to validate the model's analytical results.
• Classification : 93-xx, 93-10, Mathematical modeling or simulation for problems pertaining to systems and control theory
• Author(s) :
  • Michael Olaniyi Adeniyi (Lagos State University of Science and Technology)
  • Raphael Oluwaseun Aderele (Lagos State University of Science and Technology )
  • Olajumoke Y Oludoun (Department of Mathematics, Bowen University, Iwo, Nigeria)
  • Matthew Iwada Ekum (Lagos State University of Science and Technology)
  • Segun Isaac Oke (Department of Mathematics, Ohio University, Athens, OH 45701-2979, USA)

[00470] Mathematical and Exploratory Data Analysis on Blood Transfusion Transmitted Malaria

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @A511
• Type : Contributed Talk
• Abstract : Malaria is a disease spread by an infected mosquito or through transfusion of plasmodium-infected blood to susceptible individuals. Many interventions have been implemented to control malaria transmission, including blood screening, Long-Lasting Insecticide Bed Nets (LLIN), treatment with an anti-malaria drug, spraying chemicals/pesticides on mosquito breeding sites, and indoor residual spray, among others. As a result, a deterministic model is developed to study the impact of various malaria control and mitigation strategies against malaria transmission.
• Classification : 93-xx, 93-10, Mathematical modeling or simulation for problems pertaining to systems and control theory
• Author(s) :
  • Michael Olaniyi Adeniyi (Lagos State University of Science and Technology)
  • Raphael Oluwaseun Aderele (Lagos State University of Science and Technology )
  • Olajumoke Y Oludoun (Department of Mathematics, Bowen University, Iwo, Nigeria)
  • Matthew Iwada Ekum (Lagos State University of Science and Technology)
  • Segun Isaac Oke (Department of Mathematics, Ohio University, Athens, OH 45701-2979, USA)

MS [00955] Incorporating Immune System and Heterogeneous Dynamics into Infectious Disease Modeling

room : A512

• [04516] Modelling vector-borne disease dynamics and the impact of new interventions
  • Format : Online Talk on Zoom
  • Author(s) :
    • Ilaria Dorigatti (Imperial College London)
  • Abstract : In this seminar, I will present recent modelling studies developed to analyse the transmission dynamics of vector-borne diseases and to quantify the efficacy of a new dengue antiviral drug (JNJ-1802) from in-vitro and in-vivo experiments and a dengue vaccine candidate (TAK-003) using phase-3 clinical trial data. These models can help assess the population-level impact of novel control interventions across transmission settings. I will discuss current challenges as well as opportunities.
• [04353] Hierarchical model of West Nile virus incorporating spatio-temporal environmental effects
  • Format : Talk at Waseda University
  • Author(s) :
    • Laura Albrecht (Colorado School of Mines)
  • Abstract : West Nile virus is primarily transmitted between mosquitoes and birds, with humans as incidental hosts. Climate change may increase the risk of human infections as climatic variables have been shown to accelerate mosquito development, biting rates, and the incubation period of the disease. We developed a spatio-temporal hierarchical SEIR model that incorporates environmental covariates related to climate change. We use a Bayesian paradigm to fit our model and to predict human cases.
• [04123] How genomic data can inform contact patterns in epidemiological models
  • Format : Talk at Waseda University
  • Author(s) :
    • Julie Allison Spencer (Los Alamos National Laboratory)
    • Emma Goldberg (Los Alamos National Laboratory)
    • Sara Del Valle (Los Alamos National Laboratory)
  • Abstract : Infectious diseases threaten global health, as illustrated by the COVID-19 pandemic. Population-level models have been essential for understanding and anticipating impacts, but their ability to forecast outcomes accurately has been limited due to the rapid evolution of viruses and limited availability of parameters. Using sequenced SARS-CoV-2 genomes with associated age metadata, we inferred phylogenetic trees and used a birth-death branching model to understand the role of heterogeneous age structure on transmission pathways.
• [05574] Capturing heterogeneity: Differential effects of temperature on Culex mosquito vectors
  • Format : Talk at Waseda University
  • Author(s) :
    • Sarah Moser (Los Alamos National Laboratory)
  • Abstract : Culex spp. mosquitoes are the primary transmission vectors for West Nile virus (WNV) worldwide. The differential effects of temperature on mosquito range, distribution, and abundance pose challenges for disease forecasting and mitigation. Current models often assume a single vector species; through our scoping review on thermal response for Culex mosquito life history traits, we show the need to implement real-world species heterogeneity and present a useful data resource for modelers.

contributed talk: CT180

room : A601

[01364] Time-Delay Systems: An Overview

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @A601
• Type : Contributed Talk
• Abstract : Time-delay naturally arises in many real-world systems, due to the fact that the instantaneous rate of change of such systems does not only depend on their current time but rather on their previous history as well. Hence, time-delays are ubiquitous, their introduction often leads to suppression of oscillations, multistability and chaotic motion in the dynamical systems. This talk presents some models with different kinds of time-delays such as discrete, distributed and combination of both discrete and distributed time-delays with special emphasis on the reason of incorporating such delays into the system
• Classification : 92-10, 34D20
• Format : Talk at Waseda University
• Author(s) :
  • Bootan Rahman (University of Kurdistan Hewler (UKH))

[01187] Dynamic, data-driven neurodegeneration: Modelling clearance and proteopathy in Alzheimer’s disease

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @A601
• Type : Contributed Talk
• Abstract : The clinical research community has raised the alarm on the importance of studying the role of clearance in Alzheimer’s disease. We heed this alarm by developing and analysing the first network reaction-diffusion dynamical system coupling clearance and proteopathy. Analytical insights, and computational results on high-resolution brain graphs constructed from human data, demonstrate the connections between clearance and neurodegeneration. Our results suggest clearance deficits may play an important role in the onset and trajectory of Alzheimer's.
• Classification : 92-10, 37N25
• Author(s) :
  • Georgia Staf Brennan (University of Oxford)
  • Alain Goriely (University of Oxford)
  • Marie Rognes (Simula Research Laboratory)
  • Travis Thompson (Texas Tech University)
  • Hadrien Oliveri (University of Oxford)

[00828] Role of NK cells in regulation of lung cancer progression

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @A601
• Type : Contributed Talk
• Abstract : Tumor-associated neutrophils (TANs) and STAT signaling can stimulate or inhibit tumor growth. We developed and analyzed a mathematical model to address the issues of phenotypic transition and nonlinear regulation of NK cells, thus tumor dynamics, in response to various biochemical stimuli. Several optimal tumor prevention strategies including NK cells and Ionizing radiation have been developed to slow tumor growth. Therefore, We suggested how the optimal combination of anticancer treatments.
• Classification : 92B05, 92-04, 92-10, Mathematical Biology
• Format : Talk at Waseda University
• Author(s) :
  • Donggu Lee (Konkuk University)

[00927] Bone marrow stem cells and exosomes control doxorubicin-induced CRCC: A mathematical model

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @A601
• Type : Contributed Talk
• Abstract : Doxorubicin (DOX), a widely used chemotherapeutic agent, can cause neurodegeneration in the brain, which leads to cancer-related cognitive changes (CRCC). In fact, CRCC is a deteriorating condition which adversely affects the day-to-day life of cancer survivors. Recent studies reported that bone marrow mesenchymal stem cells (BMSCs) and exosome may significantly affect the CRCC conditions in a combination therapy (DOX+Exosome). In this study, we investigate the interaction among intracellular signaling (NFκB-Bcl-2-BAX), DOX, exosome, and IL-6.
• Classification : 92B05
• Format : Talk at Waseda University
• Author(s) :
  • hyungchul Kim (Konkuk University)
  • Donggu Lee (Konkuk University)
  • Haneol Cho (Konkuk university)
  • Junho Lee (Konkuk University)
  • Yangjin Kim (Konkuk University)

[01160] A mathematical study of cancer and radiotherapy towards personalized medicine

• Session Time & Room : 3E (Aug.23, 17:40-19:20) @A601
• Type : Contributed Talk
• Abstract : We present a mathematical model that describes the growth of a tumor mass, considering the interaction between the microenvironment abiotic factors and the epigenetic composition of the cancer cell population. We show the dynamics of its effects on radiotherapy treatment. Results reveal the predictive and diagnostic value of the use of mathematical models as an aid to the medical image in outlining patient-specific therapeutic protocols and optimizing the effectiveness and relapse control.
• Classification : 92B05, 65M60
• Format : Online Talk on Zoom
• Author(s) :
  • Giulia Chiari (Politecnico di Torino)

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

room : A618

• [03904] Implicit-explicit schemes for Cahn-Hilliard-Navier-Stokes equations
  • Format : Talk at Waseda University
  • Author(s) :
    • Pep Mulet (University of Valencia)
  • Abstract : Navier-Stokes-Cahn-Hilliard equations are a system of fourth-order partial differential equations that model the evolution of compressible mixtures of binary fluids (e.g. foams, solidification processes, fluid–gas interface) under gravitational effects. Our aim is to use implicit-explicit time-stepping schemes to avoid the severe restriction posed by the high order terms for the efficient numerical solution of problems with these equations.