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Generation of Low-Delay and High-Stability Multicast Tree

Computers, Materials & Continua 2023年第7期76卷 561-572页

作者： Deshun Li Zhenchen Wang Yucong Wei Jiangyuan Yao Yuyin Tan Qiuling Yang Zhengxia Wang Xingcan Cao School of Computer Science and Technology Hainan UniversityHaikouHainan570228China School of Cyberspace Security(School of Cryptology) Hainan UniversityHaikouHainan570228China Faculty of Arts University of British ColumbiaVancouverV6T1Z4Canada

Delay and stability are two key factors that affect the performance of multicast data transmission in a ***,current algorithms of tree generation hardly meet the requirements of low delay and high sta-bility *** a general network,the generation algorithm of a multicast tree with minimum delay and maximum stability is an NP-hard problem,without a precise and efficient *** address these challenges,this paper studies the generation of low-delay and high-stability multicast trees under the model of spanning tree based on stability probability,degree-constrained,edge-weighted for multicast(T-SDE).A class of algorithms was proposed which creates the multicast tree greedy on the ratio of fan-out to delay(RFD)and probability of stability of terminal to obtain a high performance in *** proposed algorithms greedily select terminals with a large RFD and a high probability of stability as forwarding nodes in the generation of the multicast tree,where the larger RFD and higher stability of upstream nodes are beneficial to achieve a low transmission delay and high stability in *** proposed RFD can be compatible with the original model,which can take advantage of network connectivity during the generation of a multicast *** paper carries out simulation experiments on Matlab R2016b to measure the performance of the proposed *** results show that the proposed algorithm can provide a smaller height,higher stability,and a lower transmission delay of the resulting multicast tree than other *** spanning tree of the proposed algorithms can support low transmission delay and high stability in multicast transmission.

关键词： Overlay network multicast tree transmission delay probability of stability greedy algorithm

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Coded Multicasting for Content Delivery over Predictable Time-Varying Satellite Communication Networks

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China Communications 2023年第6期20卷 339-367页

作者： Fan Xu Shuo Shao Meixia Tao Qin Huang Qifa Yan Xiaohu Tang Peng Cheng Laboratory ShenzhenGuangdong 518000China Department of Electronic Engineering Shanghai Jiao Tong UniversityShanghai 200240China School of Electronics and Information Engineering BeiHang UniversityBeijing 100191China School of Information Science and Technology Southwest Jiaotong UniversityChengduSichuan 611756China

With the development of astronautic technology, communication satellites now have a tremendous gain in both quantity and quality, and have already shown their capability on multi-functional converged communication other than telecommunication. Under this circumstance, increasing the transmission efficiency of satellite communication network becomes a top priority. In this paper, we focus on content delivery service on satellite networks, where each ground station may have prefetched some file fragments. We cast this problem into a coded caching framework so as to exploit the coded multicast gain for minimizing the satellite communication load. We first propose an optimization-based coded multicast scheme by considering the special property that the satellite network topology is predictable and timevariant. Then, a greedy based fast algorithm is proposed, which can tremendously reduce the computation complexity with a small loss in optimality. Simulation experiments conducted on two Walker constellation satellite networks show that our proposed coded multicast method can efficiently reduce the communication load of satellite networks.

关键词： satellite communication content delivery coded multicast greedy algorithm

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Joint Bayesian and greedy Recovery for Compressive Sensing

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Chinese Journal of Electronics 2020年第5期29卷 945-951页

作者： LI Jia China Electronics Technology Group Corporation 54th Research Institute Hebei Key Laboratory of Electromagnetic Spectrum Cognition and Control

greedy algorithms are widely used for sparse recovery in compressive sensing. Conventional greedy algorithms employ the inner product vector of signal residual and sensing matrix to determine the support, which is based on the assumption that the indexes of the larger-magnitude entries of the inner product vector are more likely to be contained in the correct ***, this assumption may be not valid when the number of measurements is not sufficient, leading to the selection of an incorrect support. To improve the accuracy of greedy recovery, we propose a novel greedy algorithm to recover sparse signals from incomplete *** entries of a sparse signal are modelled by the type-II Laplacian prior, such that the k indexes of the correct support are indicated by the largest k variance hyperparameters of the entries. Based on the proposed model, the supports can be recovered by approximately estimating the hyperparameters via the maximum a posteriori process. Simulation results demonstrate that the proposed algorithm outperforms the conventional greedy algorithms in terms of recovery accuracy, and it exhibits satisfactory recovery speed.

关键词： Sparse recovery Compressive sensing greedy algorithm Laplacian prior

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Contact pattern,current immune barrier,and pathogen virulence determines the optimal strategy of further vaccination

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Infectious Disease Modelling 2023年第1期8卷 192-202页

作者： Xiaohao Guo Ziyan Liu Shiting Yang Zeyu Zhao Yichao Guo Guzainuer Abudurusuli Shanlu Zhao Ge Zeng Shixiong Hu Kaiwei Luo Tianmu Chen State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics School of Public HealthXiamen UniversityXiamen City361102Fujian ProvincePeople's Republic of China Hunan Provincial Center for Disease Control and Prevention 405 Furong Middle Road Section OneKaifu DistrictChangsha City410001Hunan ProvincePeople's Republic of China

Background:The current outbreak of novel coronavirus disease 2019 has caused a seriousdisease burden *** are an important factor to sustain the *** with a relatively high-vaccination worldwide,the decay of vaccine efficacy andthe arising of new variants lead us to the challenge of maintaining a sufficient immunebarrier to protect the ***:A case-contact tracking data in Hunan,China,is used to estimate the contactpattern of cases for scenarios including school,workspace,etc,rather than ordinary susceptible *** on the estimated vaccine coverage and efficacy,a multi-groupvaccinated-exposed-presymptomatic-symptomatic-asymptomatic-removed model(VEFIAR)with 8 age groups,with each partitioned into 4 vaccination status groups *** optimal dose-wise vaccinating strategy is optimized based on the currentlyestimated immunity barrier of coverage and efficacy,using the greedy algorithm thatminimizes the cumulative cases,population size of hospitalization and fatality respectivelyin a certain future *** of Delta and Omicron variants are used respectivelyin the ***:The estimated contact matrices of cases showed a concentration on middle ages,and has compatible magnitudes compared to estimations from contact surveys in *** VEFIAR model is numerically *** optimal controled vaccination strategy requires immediate vaccination on the un-vaccinated high-contact population of age30e39 to reduce the cumulative cases,and is stable with different basic reproductionnumbers(R_(0)).As for minimizing hospitalization and fatality,the optimized strategy requires vaccination on the un-vaccinated of both aged 30e39 of high contact frequencyand the vulnerable ***:The objective of reducing transmission requires vaccination in age groups ofthe highest contact frequency,with more priority for un-vaccinated than un-fully or *** objective of reducing total ho

关键词： Vaccine Allocation strategy SARS-CoV-2 Optimal control Immune barrier Contact pattern greedy algorithm

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Minimizing makespan of a production batch within concurrent systems:Seru production perspective

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Journal of Management Science and Engineering 2022年第1期7卷 1-18页

作者： Yin Gai Yong Yin Jiafu Tang Shiqiang Liu College of Management Science and Engineering Dongbei University of Finance and EconomicsDalian116025China Graduate School of Business Doshisha UniversityKyoto602-8580Japan School of Economics and Management Fuzhou UniversityFuzhou350108China

This paper discusses the makespan minimization of a production batch within a specific concurrent system,seru production system.A seru production system consists of multiple independent serus.A seru is a compact assembly origination in which products are assembled from-the-beginning-to-the-end without *** capability of a seru production system is its responsiveness.A performance measure used to evaluate a seru system’s responsiveness is the makespan of production batches assembled within the seru *** study addresses the makespan minimization problem through an optimal seru loading *** problem is formulated as a min-max integer optimization *** exact dimension-reduction algorithm is developed to obtain the optimal allocation that minimizes the *** show that the solution space increases very *** contrast,our algorithm is efficient with a polynomial computational complexity of,where is the total number of serus in a seru *** verify the usefulness of the developed exact dimension-reduction algorithm,we compare it with a widely practiced greedy algorithm through *** find that our optimal algorithm is robust in most cases and the greedy algorithm is efficient when variability in production efficiencies is *** result can guide us to adopt different algorithms in different business *** the variability in production efficiencies is high,e.g.,new employees and/or new products assembly,the greedy algorithm is *** other cases,our optimal algorithm should be adopted to obtain the minimum *** also extend the method to the application of a rotating seru.

关键词： Assembly greedy algorithm Dimension reduction Exact algorithm Variability Polynomial computational complexity

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Piecewise Sparse Recovery in Union of Bases

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Journal of Mathematical Research with Applications 2023年第3期43卷 363-378页

作者： Chongjun LI Yijun ZHONG School of Mathematical Sciences Dalian University of Technology

Sparse recovery（or sparse representation） is a widely studied issue in the fields of signal processing, image processing, computer vision, machine learning and so on, since signals such as videos and images, can be sparsely represented under some frames. Most of fast algorithms at present are based on solving l0or l1minimization problems and they are efficient in sparse recovery. However, the theoretically sufficient conditions on the sparsity of the signal for l0or l1minimization problems and algorithms are too strict. In some applications, there are signals with structures, i.e., the nonzero entries have some certain distribution. In this paper,we consider the uniqueness and feasible conditions for piecewise sparse recovery. Piecewise sparsity means that the sparse signal x is a union of several sparse sub-signals xi（i=1, 2,..., N）,i.e., x=（x1T, x2T,..., xNT）T, corresponding to the measurement matrix A which is composed of union of bases A=[A1, A2,..., AN]. We introduce the mutual coherence for the sub-matrices Ai（i = 1, 2,..., N） by considering the block structure of A corresponding to piecewise sparse signal x, to study the new upper bounds of ‖x‖0（number of nonzero entries of signal） recovered by both l0and l1optimizations. The structured information of measurement matrix A is exploited to improve the sufficient conditions for successfully piecewise sparse recovery and also improve the reliability of l0and l1optimization models on recovering global sparse vectors.

关键词： piecewise sparse recovery union of bases mutual coherence greedy algorithm BP method

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Fast M-fold matching pursuit algorithm for image approximation

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Journal of Systems Engineering and Electronics 2009年第4期20卷 883-888页

作者： Gan Tao He Yanmin Zhu Weile School of Electronic Engineering Univ. of Electronic Science and Technology of China Chengdu 610054 P. R. China.

A simple and effective greedy algorithm for image approximation is proposed. Based on the matching pursuit approach, it is characterized by a reduced computational complexity benefiting from two major modifications. First, it iteratively finds an approximation by selecting M atoms instead of one at a time. Second, the inner product computations are confined within only a fraction of dictionary atoms at each iteration. The modifications are implemented very efficiently due to the spatial incoherence of the dictionary. Experimental results show that compared with full search matching pursuit, the proposed algorithm achieves a speed-up gain of 14.4-36.7 times while maintaining the approximation quality.

关键词： greedy algorithm image approximation matching pursuit

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The LP-rounding plus greed approach for partial optimization revisited

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Frontiers of Computer Science 2022年第1期16卷 67-75页

作者： Peng ZHANG School of Software Shandong UniversityJinan250101China

There are many optimization problems having the following common property:Given a total task consisting of many subtasks,the problem asks to find a solution to complete only part of these *** include the k-Forest problem and the k-Multicut problem,*** problems are called partial optimization problems,which are often *** this paper,we systematically study the LP-rounding plus greed approach,a method to design approximation algorithms for partial optimization *** approach is simple,powerful and *** show how to use this approach to design approximation algorithms for the k-Forest problem,the k-Multicut problem,the k-Generalized connectivity problem,etc.

关键词： k-Forest k-Multicut partial optimization LP-rounding greedy algorithm Approximation algorithm

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HSNR: A Network Representation Learning algorithm Using Hierarchical Structure Embedding

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Chinese Journal of Electronics 2020年第6期29卷 1141-1152页

作者： YE Zhonglin ZHAO Haixing ZHU Yu XIAO Yuzhi College of Computer Qinghai Normal University Tibetan Information Processing and Machine Translation Key Laboratory of Qinghai Province Key Laboratory of Tibetan Information Processing Ministry of Education

Vertices in the same group tend to connect densely,and usually share common *** of different sizes reflect the relations of vertices in different ranges,and also reflect the features of different orders of the *** this work,we propose a novel network representation learning algorithm by introducing group features of vertices of different orders to learn more discriminative network representations,named as network representation learning algorithm using Hierarchical structure embedding(HSNR).HSNR algorithm firstly constructs hierarchical relations of network structures of different orders based on greedy algorithm and *** order to introduce hierarchical features into the network representation learning model,HSNR algorithm then introduces the idea of multi-relational modeling from knowledge representation,and converts the hierarchical relations into the triplet form between ***,HSNR proposes a joint learning model embedding vertex triplets into the network *** experimental results show that the HSRN algorithm presented has an excellent performance in network vertex classification task on three real-world datasets.

关键词： group features network vertex classification task network structures Combinatorial mathematics HSNR algorithm hierarchical features novel network representation discriminative network representations joint learning model Hierarchical structure embedding network representation learning model Data handling techniques vertices network representation learning algorithm HSRN algorithm graph theory Computer vision and image processing techniques hierarchical relations knowledge representation greedy algorithm learning (artificial intelligence) greedy algorithms Knowledge engineering techniques

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Collision-free Scheduling of Multi-bridge Machining Systems： A Colored Traveling Salesman Problem-based Approach

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IEEE/CAA Journal of Automatica Sinica 2018年第1期5卷 139-147页

作者： Jun Li Xianghu Meng Xing Dai Ministry of Education Key Laboratory of Measurement and Control School of Computer Science and Engineering Southeast University Nanjing 210096 China IEEE

Multi-bridge machining systems(MBMS) have gained wide applications in industry due to their high production capacity and efficiency. They contain multiple bridge machines working in parallel within their partially overlapping *** scheduling problems can be abstracted into a serial-colored travelling salesman problem in which each salesman has some exclusive cities and some cities shared with its neighbor(s). To solve it, we develop a greedy algorithm that selects a neighboring city satisfying proximity. The algorithm allows a salesman to select randomly its shared cities and runs accordingly many times. It can thus be used to solve job scheduling problems for MBMS. Subsequently, a collision-free scheduling method is proposed to address both job scheduling and collision resolution issues of MBMS. It is an extension of the greedy algorithm by introducing time window constraints and a collision resolution mechanism. Thus, the augmented greedy algorithm can try its best to select stepwise a job for an individual machine such that no time overlaps exist between it and the job sequence of the neighboring machine dealt in the corresponding overlapping workspace; and remove such a time overlap only when it is inevitable. Finally, we conduct a case study of a large triplebridge waterjet cutting system by applying the proposed method.

关键词： Collision resolution greedy algorithm modeling multiple traveling salesman problem scheduling

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