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arXiv 2022年

作者： Xiao, Nachuan Hu, Xiaoyin Liu, Xin Toh, Kim-Chuan The Institute of Operations Research and Analytics National University of Singapore Singapore School of Computer and Computing Science Hangzhou City University Hangzhou China Academy of Edge Intelligence Hangzhou City University Gongshu Hangzhou China State Key Laboratory of Scientific and Engineering Computing Academy of Mathematics and Systems Science Chinese Academy of Sciences University of Chinese Academy of Sciences China Department of Mathematics Institute of Operations Research and Analytics National University of Singapore Singapore

Optimization over an embedded submanifold defined by equality constraints c(x) = 0 has attracted much interest over the past few decades due to its wide applications in various areas, including computer vision, signal processing, numerical linear algebra, and deep learning. For solving such problems, many related optimization packages have been developed based on Riemannian optimization approaches, which rely on some basic geometrical materials of Riemannian manifolds, including Riemannian gradients, retractions, vector transports, etc. These geometrical materials can be challenging to determine in general. In fact, existing packages only accommodate a few well-known manifolds whose geometrical materials are more easily accessible. For other manifolds that are not contained in these packages, the users have to develop the geometric materials by themselves. In addition, it is not always tractable to adapt the advanced features from various state-of-the-art unconstrained optimization solvers to Riemannian optimization approaches. Here we introduce a user-friendly Python package, CDOpt (available at https: //***/ under BSD 3-clause license), for solving a class of Riemannian optimization problems. CDOpt is designed to complement existing Riemannian optimization packages by transforming Riemannian optimization problems into their unconstrained counterparts through the constraint dissolving approach. We prove that the when the penalty parameter in the constraint dissolving approach is sufficiently large, Riemannian optimization problems and their unconstrained counterparts are equivalent. Therefore, solving Riemannian optimization problems through CDOpt can directly benefit from various existing solvers and the rich expertise gained over the past few decades for unconstrained optimization. Moreover, all the computations in CDOpt related to any manifold in question are conducted through its constraints expression, hence users can easily define new manifolds in

关键词： Constrained optimization

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A Stable Decoupled Perfectly Matched Layer for the 3d Wave Equation Using the Nodal Discontinuous Galerkin Method

SSRN

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SSRN 2024年

作者： Feriani, Sophia Julia Cosnefroy, Matthias Engsig-Karup, Allan Peter Warburton, Tim Pind, Finnur Jeong, Cheol-Ho Acoustic Technology Department of Electrical and Photonics Engineering Technical University of Denmark Ørsteds Plads Building 352 Kongens Lyngby2800 Denmark Treble Technologies Hafnartorg Kalkofnsvegur 2 Reykjavík101 Iceland Scientific Computing Department of Applied Mathematics and Computer Science Technical University of Denmark Richard Petersens Plads Building 324 Kongens Lyngby2800 Denmark Data & Decision Sciences Virginia Tech 727 Prices Fork Road BlacksburgVA24060 United States

In outdoor acoustics, the calculations of sound propagating in air can be computationally heavy if the domain is chosen large enough for the sound waves to decay. By strategically truncating the computational domain with an efficient boundary treatment, the computational cost is lowered. One commonly used boundary treatment is the perfectly matched layer (PML), which dampens outgoing waves without polluting the computed solution in the inner *** purpose of this study is to propose and assess a new perfectly matched layer formulation for the 3D acoustic wave equation, using the nodal discontinuous Galerkin finite element method. The formulation is based on an efficient PML formulation that can be decoupled to further increase the computational efficiency and guarantee stability without sacrificing accuracy. This decoupled PML formulation is demonstrated to be long-time stable, and an optimization procedure for the damping functions is proposed to enhance the performance of the formulation. © 2024, The Authors. All rights reserved.

关键词： Computational efficiency

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A stable decoupled perfectly matched layer for the 3D wave equation using the nodal discontinuous Galerkin method

arXiv

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arXiv 2024年

作者： Feriani, Sophia Julia Cosnefroy, Matthias Engsig-Karup, Allan Peter Warburton, Tim Pind, Finnur Jeong, Cheol-Ho Acoustic Technology Department of Electrical and Photonics Engineering Technical University of Denmark Ørsteds Plads Bygning 352 Kongens Lyngby2800 Denmark Treble Technologies Hafnartorg Kalkofnsvegur 2 Reykjavík101 Iceland Scientific Computing Department of Applied Mathematics and Computer Science Technical University of Denmark Richard Petersens Plads Building 324 Kongens Lyngby2800 Denmark Data & Decision Sciences Virginia Tech 727 Prices Fork Road BlacksburgVA24060 United States

In outdoor acoustics, the calculations of sound propagating in air can be computationally heavy if the domain is chosen large enough to fulfil the Sommerfeld radiation condition. By strategically truncating the computational domain with a efficient boundary treatment, the computational cost is lowered. One commonly used boundary treatment is the perfectly matched layer (PML) that dampens outgoing waves without polluting the computed solution in the inner domain. The purpose of this study is to propose and assess a new perfectly matched layer formulation for the 3D acoustic wave equation, using the nodal discontinuous Galerkin finite element method. The formulation is based on an efficient PML formulation that can be decoupled to further increase the computational efficiency and guarantee stability without sacrificing accuracy. This decoupled PML formulation is demonstrated to be long-time stable and an optimization procedure of the damping functions is proposed to enhance the performance of the formulation. Copyright © 2024, The Authors. All rights reserved.

关键词： Computational efficiency

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Violence Recognition from Videos using Deep Learning Techniques 9

Violence Recognition from Videos using Deep Learning Techniq...

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9th IEEE International Conference on Intelligent computing and Information Systems, ICICIS 2019

作者： Soliman, Mohamed Mostafa Kamal, Mohamed Hussein El-Massih Nashed, Mina Abd Mostafa, Youssef Mohamed Chawky, Bassel Safwat Khattab, Dina Faculty of Computer and Information Sciences Ain Shams University Scientific Computing Department Cairo Egypt

ISBN: (纸本)9781728139951

Automatic recognition of violence between individuals or crowds in videos has a broad interest. In this work, an end-to-end deep neural network model for the purpose of recognizing violence in videos is proposed. The proposed model uses a pre-trained VGG-16 on ImageNet as spatial feature extractor followed by Long Short-Term Memory (LSTM) as temporal feature extractor and sequence of fully connected layers for classification purpose. The achieved accuracy is near state-of-the-art. Also, we contribute by introducing a new benchmark called Real- Life Violence Situations which contains 2000 short videos divided into 1000 violence videos and 1000 non-violence videos. The new benchmark is used for fine-tuning the proposed models achieving a best accuracy of 88.2%. © 2019 IEEE.

关键词： Long short-term memory

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Image Retrieval Based on Self-Organizing Feature Map and Multilayer Perceptron Neural Networks Classifier 9

Image Retrieval Based on Self-Organizing Feature Map and Mul...

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9th IEEE International Conference on Intelligent computing and Information Systems, ICICIS 2019

作者： Ghaleb, Moshira S. Ebied, Hala M. Shedeed, Howida A. Tolba, Mohamed F. Faculty of Computer and Information Sciences Ain Shams University Scientific Computing Department Cairo Egypt

ISBN: (纸本)9781728139951

Content-based image retrieval (CBIR), is a type of computer vision application. It searches for an image by image content not text in large database images. According to the huge existence of image databases, the searching time and high accuracy retrieved images become a great challenge. This paper aims to find a solution to retrieve images with high accuracy results. Neural network became a hot topic in the image processing field for the past few years. This paper presents two approaches to Content-based image retrieval. The first approach used the Self-Organized Feature Map (SOFM) as a clustering method to image retrieval. The second approach consists of two phases. The first one used the SOFM as a feature extraction method. The second phase used the Multilayer Perceptron (MLP) as a classifier method. The paper studied the impact of changing some parameters values on recognition accuracy. The experiments carried out using the Wang Corel 1000 database. The results show that the SOFM+MLP improved the recognition accuracy compared to SOFM. The SOFM+MLP achieved approximately 99% average recognition accuracy. © 2019 IEEE.

关键词： Feature extraction

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Scaling laws and spatial effects of Brazilian health regions: a research protocol

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Procedia computer Science 2023年 219卷 1325-1332页

作者： Giovane Thomazini Soares Diego Bettiol Yamada Filipe Andrade Bernardi Mariane Barros Neiva Luis Pedro Lombardi Junior André Luiz Teixeira Vinci Ana Clara de Andrade Mioto Domingos Alves Ribeirão Preto Medical School University of Sao Paulo Av Bandeirantes 3900 14049900 Ribeirao Preto SP Brazil Bioengineering Postgraduate Program Av Trabalhador Sao-Carlense 400 13566590 Sao Carlos SP Brazil Institute of Mathematics and Computer Sciences Av Trabalhador Sao-Carlense 400 13566590 Sao Carlos SP Brazil Institute of Mathematics Statistics and Scientific Computing State University of Campinas Rua Sérgio Buarque de Holanda 651 13083859 Campinas SP Brazil

The literature has already consolidated the importance of health regions for Brazilian public health. Complexity properties strongly mark such regions. In this context, there are abundant indications that health regions should be analyzed with approaches linked to the sciences of complexity. One of these approaches, the estimation of scaling laws, can describe important properties of socio-spatial elements. However, no studies estimate the scaling laws of Brazilian health regions. This research protocol can remedy this limitation, proposing the estimation of scaling laws of the previously mentioned regions, mainly considering variables relevant to Brazilian public health. Still, this paper can substantially mitigate other relevant limitations of usual research that estimate scaling laws of socio-spatial elements. These mitigations, which provide advances in the literature on estimating scaling laws, are given by the proposal of modeling (if necessary) spatial effects and estimating scaling laws for the entire population of the socio-spatial elements. According to the theory, the expected results are non-linear scaling laws, which will likely vary with space and time and coexist with relevant spatial effects. From such laws and effects, it will be possible to accurately characterize the performance of each health region through Spatial and Scale Adjusted Metropolitan Indicators and unravel spatio-temporal properties, stabilities, and instabilities of sets composed of health regions. The expected findings of this paper can help rearrange health regions and improve the quality of information used in Brazilian public health planning.

关键词： Scaling laws Spatial effects Research protocol

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A revised gomory-hu algorithm taking account of physical unavailability of network channels 27th

A revised gomory-hu algorithm taking account of physical una...

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27th International Conference on computer Networks, CN 2020

作者： Auzinger, Winfried Obelovska, Kvitoslava Stolyarchuk, Roksolyana Institute of Analysis and Scientific Computing TU Wien Vienna Austria Institute of Computer Science and Information Technologies Lviv Polytechnic National University Lviv Ukraine Institute of Applied Mathematics and Fundamental Sciences Lviv Polytechnic National University Lviv Ukraine

ISBN: (纸本)9783030507183

The classical Gomory-Hu algorithm aims for finding, for given input flows, a network topology for data transmission and bandwidth of its channels which are optimized subject to minimal bandwidth criteria. In practice, it may occur that some channels between nodes of the network are not active. Ignoring such channels using the topology obtained be the Gomory-Hu algorithm will not lead to an optimal flow-rate. In this paper the focus is on a modified algorithm taking into account deficient channels. While the classical algorithm generates a sequence of ring subnets, in our modified version the use of deficient channels is checked at intermediate stages in each cycle of the algorithm. When forming ring subnets, the availability of new channels to be introduced into the ring subnet is checked and in the case of unavailability another ring closest to the optimal one is selected. The network optimized by this modified algorithm guarantees the transmission of the maximum input stream. © Springer Nature Switzerland AG 2020.

关键词： Network topology

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Foundation Models for Atomistic Simulation of Chemistry and Materials

arXiv

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arXiv 2025年

作者： Yuan, Eric C.-Y. Liu, Yunsheng Chen, Junmin Zhong, Peichen Raja, Sanjeev Kreiman, Tobias Vargas, Santiago Xu, Wenbin Head-Gordon, Martin Yang, Chao Blau, Samuel M. Cheng, Bingqing Krishnapriyan, Aditi Head-Gordon, Teresa Kenneth S. Pitzer Theory Center Department of Chemistry United States Department of Chemical and Biomolecular Engineering United States Electrical Engineering and Computer Science United States Bakar Institute of Digital Materials for the Planet University of California BerkeleyCA94720 United States Chemical Sciences Division United States Applied Mathematics and Computational Research Division United States Energy Technologies Area United States National Energy Research Scientific Computing Center Lawrence Berkeley National Laboratory BerkeleyCA94720 United States

Given the power of large language and large vision models, it is of profound and fundamental interest to ask if a foundational model based on data and parameter scaling laws and pre-training strategies is possible for learned simulations of chemistry and materials. The scaling of large and diverse datasets and highly expressive architectures for chemical and materials sciences should result in a foundation model that is more efficient and broadly transferable, robust to out-of-distribution challenges, and easily fine-tuned to a variety of downstream observables, when compared to specific training from scratch on targeted applications in atomistic simulation. In this Perspective we aim to cover the rapidly advancing field of machine learned interatomic potentials (MLIP), and to illustrate a path to create chemistry and materials MLIP foundation models at larger scale. © 2025, CC BY-SA.

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Measuring and Comparing QoE of Hybrid VR Applications under Increased Network Load

Measuring and Comparing QoE of Hybrid VR Applications under ...

引用

Immersive Learning Research Network (iLRN), Conference of the

作者： Ioannis Doumanis Daphne Economou Lemonia Argyriou S School of Physical Sciences and Computing University of Central Lanchashire Preston UK School of Computer Science and Engineering University of Westminster London UK Research Associate at National Center for Scientific Research “Demokritos” Athens GR

The elements of presence and interaction have been connected with high-quality learning in online learning environments. This can be achieved by offering learning environments and material that can engage the learner throughout the learning experience, allowing them to connect with the content, find relevance, construct meaning and critical thinking. Hybrid VR applications offer great potential for engaging learners in environments that accurately capture the world, allowing them to make personal connections and find relevance. Coupled with a branching narrative, computer-generated imagery (CGI) and interactivity can lead to highly engaging learning experiences. Hybrid VR applications, though, are bandwidth-demanding that can impact the learning experience. This paper presents a study comparing the Quality of Experience (QoE) of a hybrid VR application streamed over the standard internet and POINT network under increased network load. The paper presents the project motivations, a pilot study and its output. It closes with conclusions about the effect of the QoE and presence in learning and future directions.

关键词： Streaming media Quality of experience Standards

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Sensing With Communication Signals: From Information Theory to Signal Processing

arXiv

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arXiv 2025年

作者： Liu, Fan Liu, Ya-Feng Cui, Yuanhao Masouros, Christos Xu, Jie Han, Tony Xiao Buzzi, Stefano Eldar, Yonina C. Jin, Shi National Mobile Communications Research Laboratory School of Information Science and Engineering Southeast University Nanjing210096 China State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematicsand Scientific/Engineering Computing Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing100190 China Department of Communication Engineering Beijing University of Posts and Telecommunications Beijing100876 China Department of Electronic and Electrical Engineering University College London LondonWC1E 7JE United Kingdom Guangdong518172 China Huawei Technologies Co. Ltd China Department of Electrical and Information Engineering University of Cassino and Southern Lazio CassinoI-03043 Italy Department of Electronics Information and Bioengineering Politecnico di Milano MilanoI-20133 Italy ParmaI-43124 Italy Faculty of Mathematics and Computer Science Weizmann Institute of Science Rehovot Israel

The Integrated Sensing and Communications (ISAC) paradigm is anticipated to be a cornerstone of the upcoming 6G networks. In order to optimize the use of wireless resources, 6G ISAC systems need to harness the communication data payload signals, which are inherently random, for both sensing and communication (S&C) purposes. This tutorial paper provides a comprehensive technical overview of the fundamental theory and signal processing methodologies for ISAC transmission with random communication signals. We begin by introducing the deterministic-random tradeoff (DRT) between S&C from an information-theoretic perspective, emphasizing the need for specialized signal processing techniques tailored to random ISAC signals. Building on this foundation, we review the core signal models and processing pipelines for communication-centric ISAC systems, and analyze the average squared auto-correlation function (ACF) of random ISAC signals, which serves as a fundamental performance metric for multi-target ranging tasks. Drawing insights from these theoretical results, we outline the design principles for the three key components of communication-centric ISAC systems: modulation schemes, constellation design, and pulse shaping filters. The goal is to either enhance sensing performance without compromising communication efficiency or to establish a scalable tradeoff between the two. We then extend our analysis from a single-antenna ISAC system to its multi-antenna counterpart, discussing recent advancements in multiinput multi-output (MIMO) precoding techniques specifically designed for random ISAC signals. We conclude by highlighting several open challenges and future research directions in the field of sensing with communication signals. Copyright © 2025, The Authors. All rights reserved.

关键词： Signal modulation

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