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International Symposium on Networks, Computers and Communications (ISNCC)

作者： Zhao, Guokui Yang, Mingchuan Guo, Qing Wang, Gang Harbin Inst Technol Commun Res Ctr Harbin Heilongjiang Peoples R China

ISBN: (纸本)9781538637784

Since presented by ***, the new-type network Delay and Disruption Tolerant Network (DTN) came to become a hot area of research. In recent years, many kinds of DTN routing algorithms have been proposed. With the characteristics of long time delay, high packet loss rate and intermittent connectivity. Satellite networks also belong to a kind of DTN. But meanwhile, they have their unique characteristics of satellite nodes regular running in orbits and predictable inter-satellite links on and off, for which deterministic routing algorithm is more suited in Satellite DTN networks. This paper focuses on studying the theoretical knowledge of a kind of deterministic DTN routing algorithm, Earliest-Delivery(ED) algorithm. And combining with the characteristics of the satellite network above, we propose an improved ED algorithm from three aspects of distributed routing, routing update strategy and tag - based dynamic storage scheme. Ultimately, we simulate the LEO/MEO two-layer satellite delay tolerant network in OPNET, and analyze the performance of two algorithms upon packet delivery ratio, average end-to-end delay and the number of packets destroyed in the storage queue. The result shows the improved algorithm performs better in satellite DTN network.

关键词： satellite Delay and Disruption Tolerant Network Earliest-Delivery algorithm distributed algorithm optimized routing updates time slots

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Intelligent Reflecting Surface Enhanced Wireless Network: Joint Active and Passive Beamforming Design

Intelligent Reflecting Surface Enhanced Wireless Network: Jo...

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IEEE Global Conference on Communications (GLOBECOM) / Workshop on Wireless Networking and Control for UAV

作者： Wu, Qingqing Zhang, Rui Natl Univ Singapore Dept Elect & Comp Engn Singapore Singapore

ISBN: (纸本)9781538647271

Intelligent reflecting surface (IRS) is envisioned to have abundant applications in future wireless networks by smartly reconfiguring the signal propagation for performance enhancement. Specifically, an IRS consists of a large number of low-cost passive elements each reflecting the incident signal with a certain phase shift to collaboratively achieve beamforming and suppress interference at one or more designated receivers. In this paper, we study an IRS-enhanced point-to-point multiple-input single-output (MISO) wireless system where one IRS is deployed to assist in the communication from a multi-antenna access point (AP) to a single-antenna user. As a result, the user simultaneously receives the signal sent directly from the AP as well as that reflected by the IRS. We aim to maximize the total received signal power at the user by jointly optimizing the (active) transmit beamforming at the AP and (passive) reflect beamforming by the phase shifters at the IRS. We first propose a centralized algorithm based on the technique of semidefinite relaxation (SDR) by assuming the global channel state information (CSI) available at the IRS. Since the centralized implementation requires excessive channel estimation and signal exchange overheads, we further propose a low-complexity distributed algorithm where the AP and IRS independently adjust the transmit beamforming and the phase shifts in an alternating manner until the convergence is reached. Simulation results show that significant performance gains can be achieved by the proposed algorithms as compared to benchmark schemes. Moreover, it is verified that the IRS is able to drastically enhance the link quality and/or coverage over the conventional setup without the IRS.

关键词： Intelligent reflecting surface passive array beamforming phase shifter optimization distributed algorithm

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UAV-enabled Data Gathering in Wireless Sensor Networks 37

UAV-enabled Data Gathering in Wireless Sensor Networks

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37th IEEE International Performance Computing and Communications Conference (IPCCC)

作者： Cardei, Ionut Cardei, Mihaela Papa, Rafael Florida Atlantic Univ Dept Comp & Elect Engn & Comp Sci Boca Raton FL 33431 USA

ISBN: (纸本)9781538668085

A critical aspect of wireless sensor networks is network lifetime. Power-constrained wireless sensor networks are usable as long as they can communicate sensed data to the base station. Multi-hop data gathering consumes increased energy, especially for data-intensive applications. In this paper we propose a UAV-enabled data gathering mechanism for wireless sensor networks which prolongs network lifetime compared to a traditional data gathering mechanism. Some of the aspects that we address are UAV path planning, scheduled and opportunistic data gathering, and integration of the data gathering with a node scheduling mechanism. Simulations using ns3 show that our algorithm is more efficient in terms of energy consumed and packet delivery ratio compared to traditional data gathering.

关键词： Wireless sensor networks UAV-enabled data gathering sensor scheduling distributed algorithm network lifetime

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Decentralized algorithm for Repeating Pattern Formation by Multiple Robots

Decentralized Algorithm for Repeating Pattern Formation by M...

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International Conference on Parallel and distributed Systems (ICPADS)

作者： Shan Jiang Junbin Liang Jiannong Cao Jia Wang Jinlin Chen Zhixuan Liang Department of Computing The Hong Kong Polytechnic University School of Computer and Electronic Information Guangxi University

ISBN: (纸本)9781728125848

Recently, much attention is paid to multi-robot systems due to their widespread applications such as warehouse robotics, persistent surveillance, and exploration of unknown environments. Although urgently required by the applications, coordination among multiple robots remains to be challenging. Among the problems of multi-robot coordination, pattern formation serves a fundamental one. It aims to control a group of robots to form a desired shape with some certain goals such as best formation quality, minimum makespan or minimum total distance. Existing works mainly focus on the formation of certain patterns, such as repeating squares or a circle. those approaches cannot be generalized to arbitrary pattern formation. In this paper, we propose a decentralized algorithm for a multi-robot system to generate a given formation with an arbitrary repeating pattern. We introduce basic pattern graph and assembling graph to define a repeating pattern and formation quality for measurement. Towards solving the repeating pattern formation problem, our approach is divided into two phases. The robots are grouped into multiple basic patterns in the first phase, and the patterns are assembled level by level in the second phase. Simulations and real-world experiments indicate the effectiveness and practicability of our approach.

关键词： Multi-robot system Pattern formation distributed algorithm Pattern formation embryo pattern formation Cooperating robots multi-robot systems repetitive patterns distributed algorithms basic pattern formation Unknown environments Robot Decentralized Robot System

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CHANGE-POINT DETECTION OF GAUSSIAN GRAPH SIGNALS WITH PARTIAL INFORMATION

CHANGE-POINT DETECTION OF GAUSSIAN GRAPH SIGNALS WITH PARTIA...

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IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

作者： Chen, Yanxi Mao, Xianghui Ling, Dan Gu, Yuantao Tsinghua Univ Dept Elect Engn Beijing 100084 Peoples R China

ISBN: (纸本)9781538646588

In a change-point detection problem, a sequence of signals switches from one distribution to another at an unknown time step, and the goal is to quickly and reliably detect this change. By providing new insight into signal processing and data analysis, graph signal processing promises various applications including image processing and sensor network analysis, and becomes an emerging field of research. In this work, we formulate the problem of change-point detection on graph. Under the reasonable assumption of normality, we propose a CUSUM-based algorithm for change-point detection with an arbitrary, unknown and perhaps time-varying mean shift after the change-point. We further propose a decentralized, distributed algorithm, which requires no fusion center, to reduce computational complexity, as well as costs and delays of communication. Numerical results on both synthetic and real-world data demonstrate that our algorithms are efficient and accurate.

关键词： Change-point detection graph signal processing CUSUM distributed algorithm

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Brief Announcement: Simple and Local Independent Set Approximation 18

Brief Announcement: Simple and Local Independent Set Approxi...

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37th ACM SIGACT-SIGOPS Symposium on Principles of distributed Computing (PODC)

作者： Boppana, Ravi B. Halldorsson, Magnus M. Rawitz, Dror MIT Cambridge MA 02139 USA Reykjavik Univ Reykjavik Iceland Bar Ilan Univ Ramat Gan Israel

ISBN: (纸本)9781450357951

We bound the performance guarantees that follow from Turan-like bounds for unweighted and weighted independent sets in bounded degree graphs. In particular, a randomized approach of Boppana forms a simple 1-round distributed algorithm, as well as a streaming and preemptive online algorithm. We show it gives a tight (Delta + 1)/2-approximation in unweighted graphs of maximum degree Delta, which is best possible for 1-round distributed algorithms. For weighted graphs, it gives only a (Delta + 1)-approximation, but a simple modification results in an asymptotic expected 0.529(Delta + 1)-approximation.

关键词： independent set Turan bound approximation algorithm distributed algorithm

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Event-based Diffusion Kalman Filter Strategy for Clock Synchronization in WSNs

Event-based Diffusion Kalman Filter Strategy for Clock Synch...

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International Conference on Networking and Network Applications (NaNA)

作者： Yang, Shujie Xu, Changqiao Guan, Jianfeng Zhang, Tao Beijing Univ Posts & Telecommun State Key Lab Networking & Switching Technol Beijing 100876 Peoples R China

ISBN: (纸本)9781538683033

As a distributed system, most applications in wireless sensor networks (WSNs) require clock synchronization as support. However, clock crystal oscillators in WSNs are highly susceptible to the environment. The problem of clock synchronization among sensors in WSNs is urgently to be solved. Therefore, in this paper, a state-space model considering the distributed characteristics of WSNs is set up to solve clock synchronization problems. Based on this model, a diffusion Kalman filter is put forward to implement compensation of clock offset and clock skew. Furthermore, an event-based diffusion Kalman filter algorithm is proposed, in which, the ebDKF will be executed only when some event happens. Through this proposed solution, it can achieve close performances with DKF implement but reduce computational cost significantly, which is particularly adaptive to the low power and low cost properties of WSNs. At last, experiments is shown to support these theoretical algorithm well.

关键词： Kalman filter distributed algorithm quantized information MSD

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Multi-agent Network Flow Design to Solve Matrix Equation Based on Nonsmooth Convex Optimization 37

Multi-agent Network Flow Design to Solve Matrix Equation Bas...

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37th Chinese Control Conference (CCC)

作者： Deng, Wen Zeng, Xianlin Hong, Yiguang Univ Chinese Acad Sci Sch Math Sci Beijing 100049 Peoples R China Chinese Acad Sci Acad Math & Syst Sci LSC Beijing 100190 Peoples R China Beijing Inst Technol Sch Automat Beijing 100081 Peoples R China

ISBN: (纸本)9789881563958

This paper studies the distributed computation of a linear matrix equation in the form of Sigma(r)(i=1) A(i) X B-i = Sigma(r)(i=1) C-i, over multi-agent networks from an optimization perspective, with some nonsmooth requirements of the optimization variable X at the same time. In this multi-agent network, agent i can only get access to A(i), B-i, C-i and communicate with its neighbors. Then, a distributed continuous-time algorithm, from a distributed constrained optimization viewpoint, is proposed to obtain the solution with balance between its least squares bias and requirements of the nonsmooth convex function, where the saddle point method and derivative feedback technique are employed to deal with complicated problem. With help of the Lyapunov stability and semi-stability analysis, we prove the convergence of the algorithm for any initial condition.

关键词： Multi-agent networks distributed algorithm linear matrix equation nonsmooth convex function semi-stability

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Deterministic distributed construction of T-dominating sets in time T

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DISCRETE APPLIED MATHEMATICS 2017年 222卷 172-178页

作者： Miller, Avery Pelc, Andrzej Univ Quebec Outaouais Gatineau PQ Canada

A k-dominating set is a set D of nodes of a graph such that, for each node v, there exists a node w is an element of D at distance at most k from v. Our aim is the deterministic distributed construction of small T-dominating sets in time T in networks modelled as undirected n-node graphs and under the LOCAL communication model. For any positive integer T, if b is the size of a pairwise disjoint collection of balls of radii at least T in a graph, then b is an obvious lower bound on the size of a T-dominating set. Our first result shows that, even on rings, it is impossible to construct a T-dominating set of sizes asymptotically b (i.e., such that s/b -> 1) in time T. In the range of time T is an element of Theta(log* n), the size of a T-dominating set turns out to be very sensitive to multiplicative constants in running time. Indeed, it follows from Kutten and Peleg (1998), that for time T = gamma log* n with large constant gamma, it is possible to construct a T-dominating set whose size is a small fraction of n. By contrast, we show that, for time T = alpha log* n for small constant alpha, the size of a T-dominating set must be a large fraction of n. Finally, when T is an element of o(log* n), the above lower bound implies that, for any constant x < 1, it is impossible to construct a T-dominating set of size smaller than xn, even on rings. On the positive side, we provide an algorithm that constructs a T-dominating set of size n - Theta(T) on all graphs. (C) 2017 Elsevier B.V. All rights reserved.

关键词： T-dominating set LOCAL model distributed algorithm Undirected network

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A Novel Multilevel Index Model for distributed Service Repositories

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Tsinghua Science and Technology 2017年第3期22卷 273-281页

作者： Zhao Xu Yan Wu Dejun Miao Lu Liu School of Computer Science and Communication Engineering Jiangsu UniversityZhenjiang 212013China Department of ComputerScience Boise State UniversityID 83725USA Department of Computing and Mathematics University of DerbyDerbyDE22 1GBUK Department of Computing and Mathematics University of DerbyDerbyDE22 1GBUK and the School of Computer Science and Communication EngineeringJiangsu UniversityZhenjiang 212013China

This study, based on the theory of equivalence relations, proposes a novel multilevel index model for decentralized service repositories to eliminate redundant information and enhance the time-management quality of the service retrieval process of the service repository architecture. An efficient resource discovery algorithm based on Discrete Hash Tables is presented to enable efficient and effective retrieval services among different distributed repositories. The performance of the proposed model and the supporting algorithms have been evaluated in a distributed environment. Experimental results validate the effectiveness of our proposed indexing model and search algorithm.

关键词： service computing distributed algorithm service retrieval service storage

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