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arXiv 2024年

作者： Biniaz, Ahmad Maheshwari, Anil Mitchell, Joseph S.B. Odak, Saeed Polishchuk, Valentin Shermer, Thomas School of Computer Science University of Windsor Canada School of Computer Science Carleton University Canada Department of Applied Mathematics and Statistics Stony Brook University United States School of Electrical Engineering and Computer Science University of Ottawa Canada Linköping Univeristy Sweden School of Computing Science Simon Fraser University Canada

We study the problem of guarding the boundary of a simple polygon with a minimum number of guards such that each guard covers a contiguous portion of the boundary. First, we present a simple greedy algorithm for this problem that returns a guard set of size at most OPT + 1, where OPT is the number of guards in an optimal solution. Then, we present a polynomial-time exact algorithm. While the algorithm is not complicated, its correctness proof is rather involved. This result is interesting in the sense that guarding problems are typically NP-hard and, in particular, it is NP-hard to minimize the number of guards to see the boundary of a simple polygon, without the contiguous boundary guarding constraint. From the combinatorial point of view, we show that any n-vertex polygon can be guarded by at most ⌊n−2/ 2⌋ guards. This bound is tight because there are polygons that require this many guards. © 2024, CC BY.

关键词： NP-hard

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Exact Output Synchronization of Discrete-Time Multi-Agent Systems in the Presence of Disturbances and Measurement Noise with Known Frequencies via Scale-Free Protocol Design

Exact Output Synchronization of Discrete-Time Multi-Agent Sy...

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Chinese Control Conference (CCC)

作者： Zhenwei Liu Meirong Zhang Ali Saberi Anton A. Stoorvogel College of Information Science and Engineering Northeastern University Shenyang China School of Engineering and Applied Science Gonzaga University Spokane WA USA School of Electrical Engineering and Computer Science Washington State University Pullman WA USA Department of Electrical Engineering Mathematics and Computer Science University of Twente Enschede The Netherlands

This paper aims to achieve scalable exact output synchronization for discrete-time homogeneous multi-agent systems in the presence of disturbances and measurement noise with known frequencies. The key contribution of this paper is on the distributed protocol that only uses the information of agent models, rather than the communication network information and the agent number, so as to achieve the scalable exact synchronization under disturbances and measurement noise. The validity of the protocol is verified by numerical simulations with arbitrarily chosen number of agents.

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Chaotic RIME optimization algorithm with adaptive mutualism for feature selection problems

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computers in Biology and Medicine 2024年 179卷 108803-108803页

作者： Abdel-Salam, Mahmoud Hu, Gang Çelik, Emre Gharehchopogh, Farhad Soleimanian EL-Hasnony, Ibrahim M. Faculty of Computer and Information Science Mansoura University Mansoura35516 Egypt Department of Applied Mathematics Xi'an University of Technology Xi'an710054 China Department of Electrical and Electronics Engineering Faculty of Engineering Düzce University Düzce Turkey Department of Computer Engineering Urmia Branch Islamic Azad University Urmia Iran

The RIME optimization algorithm is a newly developed physics-based optimization algorithm used for solving optimization problems. The RIME algorithm proved high-performing in various fields and domains, providing a high-performance solution. Nevertheless, like many swarm-based optimization algorithms, RIME suffers from many limitations, including the exploration-exploitation balance not being well balanced. In addition, the likelihood of falling into local optimal solutions is high, and the convergence speed still needs some work. Hence, there is room for enhancement in the search mechanism so that various search agents can discover new solutions. The authors suggest an adaptive chaotic version of the RIME algorithm named ACRIME, which incorporates four main improvements, including an intelligent population initialization using chaotic maps, a novel adaptive modified Symbiotic Organism Search (SOS) mutualism phase, a novel mixed mutation strategy, and the utilization of restart strategy. The main goal of these improvements is to improve the variety of the population, achieve a better balance between exploration and exploitation, and improve RIME's local and global search abilities. The study assesses the effectiveness of ACRIME by using the standard benchmark functions of the CEC2005 and CEC2019 benchmarks. The proposed ACRIME is also applied as a feature selection to fourteen various datasets to test its applicability to real-world problems. Besides, the ACRIME algorithm is applied to the COVID-19 classification real problem to test its applicability and performance further. The suggested algorithm is compared to other sophisticated classical and advanced metaheuristics, and its performance is assessed using statistical tests such as Wilcoxon rank-sum and Friedman rank tests. The study demonstrates that ACRIME exhibits a high level of competitiveness and often outperforms competing algorithms. It discovers the optimal subset of features, enhancing the accuracy of c

关键词： Feature Selection

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Detecting 5G Narrowband Jammers with CNN, k-nearest Neighbors, and Support Vector Machines

Detecting 5G Narrowband Jammers with CNN, k-nearest Neighbor...

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IEEE International Workshop on Information Forensics and Security (WIFS)

作者： Matteo Varotto Florian Heinrichs Timo Schürg Stefano Tomasin Stefan Valentin Dep. of Computer Science Darmstadt University of Applied Sciences Germany Dep. of Medical Engineering and Technomathematics FH Aachen University of Applied Sciences Germany Dep. of Information Engineering Dep. of Mathematics University of Padova Italy Sciences Germany

ISBN: (数字)9798350364422

ISBN: (纸本)9798350364439

5G cellular networks are particularly vulnerable against narrowband jammers that target specific control sub-channels in the radio signal. One mitigation approach is to detect such jamming attacks with an online observation system, based on machine learning (ML). We propose to detect jamming at the physical layer with an ML model that performs binary classification. Based on data from an experimental 5G network, we study the performance of different classification models. A convolutional neural network will be compared to support vector machines and k-nearest neighbors, where the last two methods are combined with principal component analysis. The obtained results show substantial differences in terms of classification accuracy and computation time.

关键词： Support vector machines Accuracy 5G mobile communication Computational modeling Wireless networks Nearest neighbor methods Convolutional neural networks Jamming Principal component analysis Narrowband

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Relevance of the Basset history term for Lagrangian particle dynamics

arXiv

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arXiv 2024年

作者： Urizarna-Carasa, Julio Ruprecht, Daniel von Kameke, Alexandra Padberg-Gehle, Kathrin Lehrstuhl Computational Mathematics Institut für Mathematik Technische Universität Hamburg Hamburg Germany Heinrich-Blasius-Institute Faculty of Engineering and Computer Science Hamburg University of Applied Sciences Hamburg Germany Applied Mathematics Institute for Mathematics and its Didactics Leuphana University Lüneburg Lüneburg Germany

The movement of small but finite spherical particles in a fluid can be described by the Maxey-Riley equation (MRE) if they are too large to be considered passive tracers. The MRE contains an integral "history term" modeling wake effects, which causes the force acting on a particle at some given time to depend on its full past trajectory. The history term causes complications in the numerical solution of the MRE and is therefore often neglected, despite both numerical and experimental evidence that its effects are generally not negligible. By numerically computing trajectories with and without the history term of a large number of particles in different flow fields, we investigate its impact on the large-scale Lagrangian dynamics of simulated particles. We show that for moderate to large Stokes numbers, ignoring the history term leads to significant differences in clustering patterns. Furthermore, we compute finite-time Lyapunov exponents and show that, even for small particles, the differences in the resulting scalar field from ignoring the BHT can be significant, in particular if the underlying flow is turbulent. Copyright © 2024, The Authors. All rights reserved.

关键词： Lagrange multipliers

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Mixed Contact Problem for the Lamé System with Piecewise Constant Main Coefficients

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Journal of Mathematical sciences (United States) 2023年第1期276卷 168-190页

作者： Vuong, Tran Quang Soldatov, A.P. Dalat University Lam Dong Da Lat Viet Nam Federal Research Center “Computer Science and Control” RAS 40 Vavilova St. Moscow 119333 Russian Federation Moscow Center for Fundamental and Applied Mathematics National Research University “Moscow Power Engineering Institute” 14 Krasnokazarmennaya St. Moscow 111250 Russian Federation

We construct the fundamental matrix of solutions to the Lamé system with constant main coefficients in the general anisotropic case. Using the fundamental matrix, we obtain an integral representation of functions of a Hölder class in a closed domain with Lyapunov boundary. In the case of an infinite domain, the representation is described within the framework of weighted Hölder spaces (of functions with power behavior at infinity). Based on this representation, we can reduce the mixed contact boundary value problem for the Lamé system with piecewise constant main coefficients to a system of integral equations that are Fredholm in the domain and are singular on the boundary. As a result, we establish a Fredholm criterion and indicate the index for this problem. © 2023, Springer Nature Switzerland AG.

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Acoustic cavitation bubble under influence of frequency ultrasound: Numerical analysis

Acoustic cavitation bubble under influence of frequency ultr...

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Electronic engineering (ICEEM), International Conference on

作者： A. K. Abu-Nab A. F. Abu-Bakr Zain AbuShaeer Department of Mathematics and Computer Science Faculty of Science Menoufia University Shebin 32511 Egypt Phystech School of Applied Mathematics and Informatics Moscow Institute of Physics and Technology Moscow Russia Department of Mathematics and Computer Science Faculty of Science Menoufia University Shebin El-Koom Egypt Department of Basic Science Higher Institute of Engineering and Technology Kafrelsheikh Egypt

This work presents a numerical investigation of acoustic cavitation in Newtonian fluid based on frequency ultrasound. The model of ultrasonic cavitation dynamics is formulated by a modified Rayleigh-Plesset equation and an acoustic pressure equation. The exponential B-Spline collection method was employed to obtain the numerical solutions of the given cavitation bubble model, considering the effect of acoustic pressure. The behaviour of the cavitation microbubbles' radius and the internal pressure of acoustic cavitation were examined at different values of frequencies. The obtained results reveal the importance of frequencies in ultrasound, which play a vital role in changing the behaviour of cavitation bubbles.

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Leveraging LLMs for Multimodal Medical Time Series Analysis 9

Leveraging LLMs for Multimodal Medical Time Series Analysis

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9th Machine Learning for Healthcare Conference, MLHC 2024

作者： Chan, Nimeesha Parker, Felix Bennett, William Wu, Tianyi Jia, Mung Yao Fackler, James Ghobadi, Kimia Department of Civil and Systems Engineering Johns Hopkins University BaltimoreMD United States Department of Anesthesiology and Critical Care Medicine Johns Hopkins University BaltimoreMD United States Department of Applied Mathematics and Statistics Johns Hopkins University BaltimoreMD United States Department of Computer Science Johns Hopkins University BaltimoreMD United States

The complexity and heterogeneity of data in many real-world applications pose significant challenges for traditional machine learning and signal processing techniques. For instance, in medicine, effective analysis of diverse physiological signals is crucial for patient monitoring and clinical decision-making and yet highly challenging. We introduce MedTsLLM, a general multimodal large language model (LLM) framework that effectively integrates time series data and rich contextual information in the form of text to analyze physiological signals, performing three tasks with clinical relevance: semantic segmentation, boundary detection, and anomaly detection in time series. These critical tasks enable deeper analysis of physiological signals and can provide actionable insights for clinicians. We utilize a reprogramming layer to align embeddings of time series patches with a pretrained LLM’s embedding space and make effective use of raw time series, in conjunction with textual context. Given the multivariate nature of medical datasets, we develop methods to handle multiple covariates. We additionally tailor the text prompt to include patient-specific information. Our model outperforms state-of-the-art baselines, including deep learning models, other LLMs, and clinical methods across multiple medical domains, specifically electrocardiograms and respiratory waveforms. MedTsLLM presents a promising step towards harnessing the power of LLMs for medical time series analysis that can elevate data-driven tools for clinicians and improve patient outcomes. © 2024 Authors.

关键词： Semantics

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LIMIT LAWS FOR GROMOV-WASSERSTEIN ALIGNMENT WITH APPLICATIONS TO TESTING GRAPH ISOMORPHISMS

arXiv

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arXiv 2024年

作者： Rioux, Gabriel Goldfeld, Ziv Kato, Kengo Center for Applied Mathematics Cornell University United States School of Electrical and Computer Engineering Cornell University United States Department of Statistics and Data Science Cornell University United States

The Gromov-Wasserstein (GW) distance enables comparing metric measure spaces based solely on their internal structure, making it invariant to isomorphic transformations. This property is particularly useful for comparing datasets that naturally admit isomorphic representations, such as unlabelled graphs or objects embedded in space. However, apart from the recently derived empirical convergence rates for the quadratic GW problem, a statistical theory for valid estimation and inference remains largely obscure. Pushing the frontier of statistical GW further, this work derives the first limit laws for the empirical GW distance across several settings of interest: (i) discrete, (ii) semi-discrete, and (iii) general distributions under moment constraints under the entropically regularized GW distance. The derivations rely on a novel stability analysis of the GW functional in the marginal distributions. The limit laws then follow by an adaptation of the functional delta method. As asymptotic normality fails to hold in most cases, we establish the consistency of an efficient estimation procedure for the limiting law in the discrete case, bypassing the need for computationally intensive resampling methods. We apply these findings to testing whether collections of unlabelled graphs are generated from distributions that are isomorphic to each other. Copyright © 2024, The Authors. All rights reserved.

关键词： Delta functions

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Rescattering of stimulated Raman side scattering in nonuniform plasmas

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Matter and Radiation at Extremes 2024年第5期9卷 68-76页

作者： S.Tan Q.Wang Y.Chen W.B.Yao C.Z.Xiao J.F.Myatt School of Physics and Electronics Hunan UniversityChangsha 410082China Institute of Applied Physics and Computational Mathematics Beijing 100094China School of Electrical and Information Engineering Anhui University of Science and TechnologyHuainanAnhui 232001China Department of Electrical and Computer Engineering University of Alberta9211116 St.NWEdmontonAlberta T6G 1H9Canada

Rescattering of stimulated Raman side scattering(SRSS)is observed for the first time via two-dimensional(2D)particle-in-cell(PIC)*** construct a theoretical model for the rescattering process,which can predict the region of occurrence of mth-order SRSS and estimate its *** rescattering process is identified by the 2D PIC simulations under typical conditions of a direct-drive inertial confinement fusion *** electrons produced by second-order SRSS propagate nearly perpendicular to the density gradient and gain nearly the same energy as in first-order SRSS,but there is no cascade acceleration to produce superhot *** studies for a wide range of ignition conditions show that SRSS and associated rescatterings are robust and important processes in inertial confinement fusion.

关键词： nonuniform acceleration scattering

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