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A High-Order Hybrid-Spectral Incompressible Navier–Stokes Model for Non-Linear Water Waves

International Journal for Numerical Methods in Fluids 2025年第6期97卷 1009-1021页

作者： Melander, Anders Ebstrup Bitsch, Max Chen, Dong Peter Engsig-Karup, Allan Department of Applied Mathematics and Computer Science Technical University of Denmark Kongens Lyngby Denmark

We present a new high-order accurate computational fluid dynamics model based on the incompressible Navier–Stokes equations with a free surface for the accurate simulation of non-linear and dispersive water waves in the time domain. The spatial discretization is based on Chebyshev polynomials in the vertical direction and a Fourier basis in the horizontal direction, allowing for the use of the fast Chebyshev and Fourier transforms for the efficient computation of spatial derivatives. The temporal discretization is done through a generalized low-storage explicit fourth-order Runge–Kutta, and for the scheme to conserve mass and achieve high-order accuracy, a velocity-pressure coupling needs to be satisfied at all Runge–Kutta stages. This results in the emergence of a Poisson pressure problem that constitutes a geometric conservation law for mass conservation. The occurring Poisson problem is proposed to be solved efficiently via an accelerated iterative solver based on a geometric (Formula presented.) -multigrid scheme, which takes advantage of the high-order polynomial basis in the spatial discretization and hence distinguishes itself from conventional low-order numerical schemes. We present numerical experiments for validation of the scheme in the context of numerical wave tanks demonstrating that the (Formula presented.) -multigrid accelerated numerical scheme can effectively solve the Poisson problem that constitute the computational bottleneck, that the model can achieve the desired spectral convergence, and is capable of simulating wave-propagation over non-flat bottoms with excellent agreement in comparison to experimental results. © 2025 The Author(s). International Journal for Numerical Methods in Fluids published by John Wiley & Sons Ltd.

关键词： Time domain analysis

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Teaching Coordination to Selfish Learning Agents in Resource-Constrained Partially Observable Markov Games

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IEEE Transactions on Automatic Control 2025年第5期70卷 3449-3455页

作者： Tsaousoglou, Georgios Technical University of Denmark Department of Applied Mathematics and Computer Science Lyngby2800 Denmark

Of increasing relevance to engineering systems are problems that include online resource allocation to agents that feature adaptation and learning capabilities. This article considers the case where a coordinator gets to design a resource allocation mechanism (i.e., a bidding-allocation-rewards protocol) to efficiently allocate a resource to selfish agents that try to gain access by learning to communicate strategically. Toward aligning the agents' incentives with the social objective, a critical-value-based mechanism is proposed. Analytic results are presented for a simple, stylized setting, whereas simulation results for a use case with reinforcement learning agents controlling flexible loads in the smart grid demonstrate the mechanism's ability to teach coordinated behavior to the distributed learners. © 1963-2012 IEEE.

关键词： Adversarial machine learning

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An infrastructure software perspective toward computation offloading between executable specifications and foundation models

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science China(Information sciences) 2025年第4期68卷 380-382页

作者： Dezhi RAN Mengzhou WU Yuan CAO Assaf MARRON David HAREL Tao XIE Key Laboratory of High Confidence Software Technologies (PKU) Ministry of Education School of Computer SciencePeking University School of Electronics Engineering and Computer Science Peking University Department of Computer Science and Applied Mathematics Weizmann Institute of Science

Foundation models(FMs) [1] have revolutionized software development and become the core components of large software systems. This paradigm shift, however, demands fundamental re-imagining of software engineering theories and methodologies [2]. Instead of replacing existing software modules implemented by symbolic logic, incorporating FMs' capabilities to build software systems requires entirely new modules that leverage the unique capabilities of ***, while FMs excel at handling uncertainty, recognizing patterns, and processing unstructured data, we need new engineering theories that support the paradigm shift from explicitly programming and maintaining user-defined symbolic logic to creating rich, expressive requirements that FMs can accurately perceive and implement.

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Unsupervised multiplex graph diffusion networks with multi-level canonical correlation analysis for multiplex graph representation learning

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science China(Information sciences) 2025年第3期68卷 66-79页

作者： Sichao FU Qinmu PENG Yange HE Baokun DU Bin ZOU Xiao-Yuan JING Xinge YOU School of Electronic Information and Communications Huazhong University of Science and Technology Platform Operation and Marketing Center JD Retail Faculty of Mathematics and Statistics Hubei Key Laboratory of Applied Mathematics Hubei University School of Computer Science Wuhan University

In recent years, unsupervised multiplex graph representation learning(UMGRL) has received increasing research interest, which aims to learn discriminative node features from the multiplex graphs supervised by data without the guidance of labels. Although these designed UMGRL methods have obtained great success in various graph-related tasks, most existing UMGRL models still have the following issues: highly depending on complex self-supervised strategies(i.e., data augmentation,pretext tasks, and negative pairs sampling), restricted receptive fields, and only aggregating low-frequency information between nodes. In this paper, we propose a simple unsupervised multiplex graph diffusion network(UMGDN) with the aid of multi-level canonical correlation analysis to solve the above issues. Specifically, we first decouple the feature transform and propagation processes of the graph convolution layer to further improve the generalization of the learnable parameters. And then, we propose adaptive diffusion propagation to capture long-range dependency relationships between nodes, not the local neighborhood interactions. Finally, a multi-level canonical correlation analysis loss on both the feature transform and propagation processes is proposed to maximize the correlation of the same node features from multiple graphs for guiding model optimization. Compared to the existing UMGRL models, our proposed UMGDN does not need to introduce any data augmentation, negative pairs sampling techniques, complex pretext tasks, and also adaptively aggregates the optimal frequency information between nodes to generate more robust node embeddings. Extensive experiments on four popular datasets and two graph-related tasks demonstrate the effectiveness of the proposed method.

关键词： unsupervised multiplex graph representation learning graph neural networks node classification node clustering

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DP-ARTS: Dynamic Prioritization for Adaptive Resource Allocation and Task Scheduling in Cloud Computing

IAENG International Journal of Computer Science

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IAENG International Journal of computer science 2025年第3期52卷 793-807页

作者： BEN ALLA, Hicham BEN ALLA, Said EZZATI, Abdellah Computer Science Mathematics and Computer Science Department Science and Technical Faculty Hassan 1 University Settat Morocco Embedded Systems and Computer Science National School of Applied Sciences of Berrechid Hassan 1 University Settat Morocco

Efficient task scheduling and resource allocation are essential for optimizing performance in cloud computing environments. The presence of priority constraints necessitates advanced solutions capable of addressing the increased complexity in the task scheduling process and resource allocation management. In this paper, we propose a novel approach, Dynamic Prioritization and Adaptive Resource Allocation and Task Scheduling (DP-ARTS), to tackle these challenges by integrating dynamic task prioritization with adaptive resource allocation and scheduling strategies. Our approach introduces a scoring mechanism to prioritize tasks based on deadlines, resource requirements, and other critical characteristics. Furthermore, we utilize K-means clustering to group Virtual Machines (VMs) according to their capabilities, facilitating more efficient task-to-VM mapping. Through simulations conducted with real-world workload traces in the CloudSim toolkit, DP-ARTS demonstrates superior performance in reducing makespan and energy consumption, while also improving resource utilization and load balancing compared to existing solutions. © (2025), (International Association of Engineers). All rights reserved.

关键词： K-means clustering

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Simpler Optimal Sorting from a Directed Acyclic Graph 8

Simpler Optimal Sorting from a Directed Acyclic Graph

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8th SIAM Symposium on Simplicity of Algorithms, SOSA 2025

作者： van der Hoog, Ivor Rotenberg, Eva Rutschmann, Daniel Department of Applied Mathematics and Computer Science Technical University of Denmark Denmark

ISBN: (纸本)9781611978315

Fredman proposed in 1976 the following algorithmic problem: Given are a ground set X, some partial order P over X, and some comparison oracle OL that specifies a linear order L over X that extends P. A query to OL has as input distinct x, x′ ∈ X and outputs whether x ′ or vice versa. If we denote by e(P) the number of linear orders that extend P, then it follows from basic information theory that log e(P) is a worst-case lower bound on the number of queries needed to output the sorted order of X. Fredman did not specify in what form the partial order is given. Haeupler, Hladík, Iacono, Rozhon, Tarjan, and Tětek ('24) propose to assume as input a directed acyclic graph, G, with m edges and n = |X| vertices. Denote by PG the partial order induced by G. Their algorithmic performance is measured in running time and the number of queries used, where they use Θ(m + n + log e(PG)) time and Θ(log e(PG)) queries to output X in its sorted order. Their algorithm is worst-case optimal, both in terms of running time and queries. Their analysis relies upon sophisticated counting arguments using entropy, recursively defined sets defined over the run of their algorithm, and vertices in the graph that they identify as bottlenecks for sorting. We do away with sophistication. We show that when the input is a directed acyclic graph then the problem admits a simple solution using Θ(m + n + log e(PG)) time and Θ(log e(PG)) queries. Especially our proofs are much simpler as we avoid the usage of advanced charging arguments, and instead rely upon two observations. Copyright © 2025 by SIAM.

关键词： Directed graphs

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Enhanced MADM Strategy with Heptapartitioned Neutrosophic Distance Metrics

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Neutrosophic Sets and Systems 2025年 78卷 74-96页

作者： Eassa, Mohamed Myvizhi, M. Elkholy, Mohamed Abdelhafeez, Ahmed Elbehiery, Hussam Computer Science Department Faculty of Information System and Computer Science October 6 University Giza12585 Egypt Applied Science Research Center Applied Science Private University Amman Jordan Department of Mathematics KPR Institute of Engineering and Technology Tamilnadu Coimbatore India Faculty of Computer Science& Engineering Alamein International University Egypt

In this work, a novel methodological approach to multi-attribute decision-making problems is developed and the notion of Heptapartitioned Neutrosophic Set Distance Measures (HNSDM) is introduced. By averaging the Penta-Partitioned Neutrosophic Distance Measures under particular conditional criteria, the suggested technique ranks the options. Additionally, we explore the fundamental characteristics of HNSDM and provide several illustrative theorems. The Heptapartitioned Neutrosophic Set Distance Measures are formulated based on the Hepta Neutrosophic Set. Lastly, a practical numerical example is provided to illustrate the efficacy of the suggested methodology. © 2025, University of New Mexico. All rights reserved.

关键词： Heptapartitioned Neutrosophic set Heptapartitioned Neutrosophic set and MADM strategy Heptapartitioned set Neutrosophic sine distance measure

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Mathematical modelling of the dynamics of typhoid fever and two modes of treatment in a Health District in Cameroon

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Mathematical Biosciences and Engineering 2025年第2期22卷 477-510页

作者： Tsafack, Thierry Jimy Kum, Cletus Kwa Tassé, Arsène Jaurès Ouemba Tsanou, Berge Department of Mathematics and Computer Science Faculty of Science University of Dschang P.O. Box 67 Dschang Cameroon Department of Mathematics Higher Teacher Training College - Bambili The University of Bamenda P.O. Box 39 Bambili Cameroon School of Computer Science and Applied Mathematics University of the Witwatersrand Johannesburg South Africa Department of Mathematics and Applied Mathematics University of Pretoria South Africa IRD Sorbonne University UMMISCO BondyF-93143 France

In this paper, we propose a novel mathematical model for indirectly transmitted typhoid fever disease that incorporates the use of modern and traditional medicines as modes of treatment. Theoretically, we provide two Lyapunov functions to prove the global asymptotic stability of the disease-free equilibrium (DFE) and the endemic equilibrium (EE) when the basic reproduction number (R0) is less than one and greater than one, respectively. The model is calibrated using the number of cumulative cases reported in the Penka-Michel health district in Cameroon. The parameter estimates thus obtained give a value of R0 = 1.2058 > 1,which indicates that the disease is endemic in the region. The forecast of the outbreak up to November 2026 suggests that the number of cases will be 21,270, which calls for urgent attention on this endemic disease. A sensitivity analysis with respect to the basic reproduction number is conducted, and the main parameters that impact the widespread of the disease are determined. The analysis highlights that the environmental transmission rate β and the decay rate µb of the bacteria in the environment are the most influential parameters for R0. This underscores the urgent need for potable water and adequate sanitation within this area to reduce the spread of the disease. Numerically, we illustrate the usefulness of recourse to any mode of treatment to lessen the number of infected cases and the necessity of switching from modern treatment to the traditional treatment, a useful adjuvant therapy. Conversely, we show that the relapse phenomenon increases the burden of the disease. Hence adopting a synergistic therapy approach will significantly mitigate typhoid disease cases and overcome the cycle of poverty within the afflicted communities. © 2025 the Author(s)

关键词： Medicinal chemistry

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Asymmetry and Condition Number of an Elliptic-Parabolic System for Biological Network Formation

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应用数学与计算数学学报 2025年第1期7卷 78-94页

作者： Clarissa Astuto Daniele Boffi Jan Haskovec Peter Markowich Giovanni Russo Applied Mathematics and Computational Sciences Department King Abdullah University of Science and Technology4700 ThuwalSaudi Arabia Applied Mathematics and Computational Sciences Department King Abdullah University of Science and Technology4700 ThuwalSaudi Arabia Department of Mathematics"F.Casorati" University of Pavia27100 PaviaItaly Applied Mathematics and Computational Sciences Department King Abdullah University of Science and Technology4700 ThuwalSaudi Arabia Department of Mathematics University of Vienna1090 ViennaAustria Department of Mathematics and Computer Science University of Catania95125 CataniaItaly

We present results of numerical simulations of the tensor-valued elliptic-parabolic PDE model for biological network *** numerical method is based on a nonlinear finite difference scheme on a uniform Cartesian grid in a two-dimensional(2D)*** focus is on the impact of different discretization methods and choices of regularization parameters on the symmetry of the numerical *** particular,we show that using the symmetric alternating direction implicit(ADI)method for time discretization helps preserve the symmetry of the solution,compared to the(non-symmetric)ADI ***,we study the effect of the regularization by the isotropic background perme-ability r＞0,showing that the increased condition number of the elliptic problem due to decreasing value of r leads to loss of *** show that in this case,neither the use of the symmetric ADI method preserves the symmetry of the ***,we perform the numerical error analysis of our method making use of the Wasserstein distance.

关键词： Bionetwork formation Cai-Hu model Leaf venation Asymmetry Conditioning number Finite-difference scheme Semi-implicit Symmetric alternating direction implicit(ADI) Wasserstein distance

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Unsupervised Assessment of Landscape Shifts Based on Persistent Entropy and Topological Preservation 1st

Unsupervised Assessment of Landscape Shifts Based on Persi...

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1st International Workshop on Discovering Drift Phenomena in Evolving Landscapes, DELTA 2024

作者： Basterrech, Sebastián Department of Applied Mathematics and Computer Science Technical University of Denmark Kongens Lyngby Denmark

ISBN: (纸本)9783031823459

Concept drift typically refers to the analysis of changes in data distribution. A drift in the input data can have negative consequences on a learning predictor and the system’s stability. The majority of concept drift methods emphasize the analysis of statistical changes in non-stationary data over time. In this context, we consider a slightly different perspective, where concept drift also integrates significant changes in the topological characteristics of the data *** this article, we introduce a novel framework for monitoring changes in multi-dimensional data streams. We explore variations in the topological structures of the data, presenting another angle on the standard concept *** developed approach is based on persistent entropy and topology-preserving projections in a continual learning scenario. The framework operates in both unsupervised and supervised environments. To show the utility of the proposed framework, we analyze the model across three scenarios using data streams generated with MNIST samples. The obtained results reveal the potential of applying topological data analysis for shift detection and encourage further research in this area. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

关键词： Concept Drift Dimensionality reduction Distribution shifts Persistent entropy Self-organizing maps

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