Bipartite Consensus of Linear Multi-Agent Systems by Distributed Event-Triggered Control

For multi-agent systems with competitive and collaborative relationships, signed graph can more intuitively express the characteristics of their interactive networks. In this paper, the bipartite consensus is investigated for multi-agent systems with structurally balanced signed graph. In order to reduce actuation burden in dynamical network environment, the event-triggering strategy is applied to bipartite consensus protocol for the multi-agent systems. The triggered condition for each agent is designed by using its own information and transmitted information of its neighbors at sampling instant and make the number of triggers of the whole systems be reduced. Based on the distributed eventtriggered control, some sufficient conditions are derived to guarantee the leaderless and leader-following bipartite consensus. Finally, some numerical examples are shown to demonstrate the effectiveness of the theoretical results.     

A New Peer-to-Peer Topology for Video Streaming Based on Complex Network Theory

A new wave of networks labeled Peer-to-Peer(P2P) networks attracts more researchers and rapidly becomes one of the most popular applications.In order to matching P2 P logical overlay network with physical topology,the position-based topology has been proposed.The proposed topology not only focuses on non-functional characteristics such as scalability,reliability,fault-tolerance,selforganization,decentralization and fairness,but also functional characteristics are addressed as well.The experimental results show that the hybrid complex topology achieves better characteristics than other complex networks’ models like small-world and scale-free models;since most of the real-life networks are both scale-free and small-world networks,it may perform well in mimicking the reality.Meanwhile,it reveals that the authors improve average distance,diameter and clustering coefficient versus Chord and CAN topologies.Finally,the authors show that the proposed topology is the most robust model,against failures and attacks for nodes and edges,versus small-world and scale-free networks.     

Bipartite Consensus of Discrete-Time Double-Integrator Multi-Agent Systems with Measurement Noise

The effects of measurement noise are investigated in the context of bipartite consensus of multi-agent systems. In the system setting, discrete-time double-integrator dynamics are assumed for the agent, and measurement noise is present for the agent receiving the state information from its neighbors. Time-varying stochastic bipartite consensus protocols are designed in order to lessen the harmful effects of the noise. Consequently, the state transition matrix of the closed-loop system is analyzed, and sufficient and necessary conditions for the proposed protocol to be a mean square bipartite consensus protocol are given with the help of linear transformation and algebraic graph theory. It is proven that the signed digraph to be structurally balanced and having a spanning tree are the weakest communication assumptions for ensuring bipartite consensus. In particular, the proposed protocol is a mean square bipartite average consensus one if the signed digraph is also weight balanced.     

非均匀拓扑网络中的分布式一致性状态估计算法

分布式一致性状态估计是传感器网络中节点对目标的一种有效的估计融合方法。针对网络非均匀拓扑情况下的一致性状态估计问题,首先,研究了分布式传感器网络一致性状态估计框架,提出了四级功能模型,从信息处理、交互及融合的角度描述了一致性状态估计技术的主要流程;其次,考虑网络非均匀拓扑时一致性收敛速度较慢的情况,根据节点间通信链接的重要性设计了基于动态拓扑信息的自适应权值分配方法,在此基础上提出了基于自适应加权的卡尔曼一致性滤波(adaptive weighted Kalman consensus filter,AW-KCF)算法。仿真结果显示,AW-KCF在非均匀拓扑的稀疏网络中具有较快的一致性收敛速度。     

基于拓扑维护的自适应多信道OLSR路由协议

OLSR是一种应用于无线移动Ad hoc网络的基于链路状态机制的先应式路由协议。在OLSR中,网络拓扑的动态变化会使节点掌握的拓扑信息失效,从而导致路由表项不全,影响路由性能。针对上述问题,提出了一种基于拓扑维护的自适应多信道路由协议MOLSR-TM,该协议把拓扑维护状况感知和自适应算法引入OLSR,以调整HELLO控制消息的发送频率和邻居记录表、拓扑记录表的刷新频率。性能分析和仿真结果表明,MOLSR-TM能改善节点的拓扑维护状况,增强动态拓扑适应能力,提高数据成功率、端到端时延和网络吞吐率等性能。     

空间网络路由协议研究

空间网络的开放媒质、动态拓扑、分布式合作、资源受限等特点,使路由协议成为该领域的研究难点,在研究空间网络节点运行规律的基础上,提出一种空间网络路由协议,采用静态配置与动态调整相结合的路由策略,在网络拓扑变化时自动对路由进行调整。利用网络仿真软件NS2搭建了空间网络仿真平台进行仿真实验,结果表明,该协议信令开销较小,具有良好的网络性能,适合应用于空间网络。     

Dynamic Routing Protocol for Computer Networkswith Clustering Topology

1.INTRODUCTIONTheroutingdecisionorselectionisoneoftheimportantresearchissuesinthenetworkfields.ItisoneoftheprincipalfunctionsofthenetworklayerorinternetlayerintheISO-OSIprotocolarchitecture.Theperformanceofroutingprotocolisrelatedtothethroughput,averagemessagedelayreliabilityandtransferableefficiencyofthecommunicationsubnetworks[4,8].Untilrecently,thevariousplanned(non-hierarchical)routingalgorithmsforthecomputernetworkshavebeenstudiedextensively,andthehierarchicalroutingtechniquesforth…     

一类转移概率部分未知的Markov跳跃系统的输入输出量化反馈控制

对一类离散时间马尔可夫跳跃系统(Markov jump systems,MJSs)的稳定性问题进行研究,考虑MJSs转移概率矩阵中的元素部分未知,且系统的控制输入通道和测量输出通道都存在信号量化的情况,其中控制器输入通道和系统输入通道的信号分别被两个不同的对数量化器量化。利用切换李雅普诺夫函数的方法,通过构造系统模态依赖且双通道量化误差依赖的李雅普诺夫函数,完成对闭环系统的稳定性分析和控制器设计。得到一组模态依赖的控制器,能够在系统的转移概率部分未知和存在双通道量化误差的条件下,保证闭环MJSs的随机稳定性。最后通过仿真实验验证了理论的有效性。     

无尺度网络平均路径长度的估计

无尺度网络的拓扑结构研究主要集中于聚类系数和平均路径长度的计算以及度分布分析. 在实际的无尺度网络中,表征网络拓扑结构的三个参数之间是互相联系的,其中一个参数均可近似用另外两个参数表示. 鉴于此,针对大规模无尺度网络的平均路径长度计算问题,基于树形结构模型给出了无尺度网络平均路径长度<l>_SF 的计算公式,并分析了网络规模和节点间连接方式对平均路径长度的影响. 分析结果表明,<l>_SF与无尺度网络的平均度数k、平均聚类系数C以及幂指数γ有关,从而将直接求解平均路径长度的复杂问题转化为间接求解,大大提高了分析无尺度网络拓扑结构的效率. 实验结果表明,提出的无尺度网络平均路径长度计算公式是有效的.     

Data-Driven Leader-Follower Output Synchronization for Networked Non-Linear Multi-Agent Systems with Switching Topology and Time-Varying Delays

This paper studies the output synchronization problem for a class of networked non-linear multi-agent systems with switching topology and time-varying delays. To synchronize the outputs, a leader is introduced whose connectivity to the followers varies with time, and a novel data-driven consensus protocol based on model free adaptive control is proposed, where the reference input of each follower is designed to be the time-varying average of the neighboring agents’ outputs. Both the case when the leader is with a prescribed reference input and the case otherwise are considered. The proposed protocol allows for time-varying delays, switching topology, and does not use the agent structure or the dynamics information implicitly or explicitly. Sufficient conditions are derived to guarantee the closed-loop stability, and conditions for consensus convergence are obtained, where only a joint spanning tree is required. Numerical simulations and practical experiments are conducted to demonstrate the effectiveness of the proposed protocol.     

Convergence of Distributed Gradient-Tracking-Based Optimization Algorithms with Random Graphs

This paper studies distributed convex optimization over a multi-agent system, where each agent owns only a local cost function with convexity and Lipschitz continuous gradients. The goal of the agents is to cooperatively minimize a sum of the local cost functions. The underlying communication networks are modelled by a sequence of random and balanced digraphs, which are not required to be spatially or temporally independent and have any special distributions. The authors use a distributed gradient-tracking-based optimization algorithm to solve the optimization problem. In the algorithm,each agent makes an estimate of the optimal solution and an estimate of the average of all the local gradients. The values of the estimates are updated based on a combination of a consensus method and a gradient tracking method. The authors prove that the algorithm can achieve convergence to the optimal solution at a geometric rate if the conditional graphs are uniformly strongly connected, the global cost function is strongly convex and the step-sizes don't exceed some upper bounds.     

Consensus design for continuous-time multi-agent systems with communication delay

This paper investigates a consensus design problem for continuous-time first-order multiagent systems with uniform constant communication delay.Provided that the agent dynamic is unstable and the diagraph is undirected,sufficient conditions are derived to guarantee consensus.The key technique is the adoption of historical input information in the protocol.Especially,when agent＇s own historical input information is used in the protocol design,the consensus condition is constructed in terms of agent dynamic,communication delay,and the eigenratio of the network topology.Simulation result is presented to validate the effectiveness of the theoretical result.     

Leader-following consensus protocols for formation control of multi-agent network

Two protocols are presented,which can make agents reach consensus while achieving and preserving the desired formation in fixed topology with and without communication timedelay for multi-agent network.First,the protocol without considering the communication time-delay is presented,and by using Lyapunov stability theory,the sufficient condition of stability for this multi-agent system is presented.Further,considering the communication time-delay,the effectiveness of the protocol based on Lyapunov-Krasovskii function is demonstrated.The main contribution of the proposed protocols is that,as well as the velocity consensus is considered,the formation control is concerned for multi-agent systems described as the second-order equations.Finally,numerical examples are presented to illustrate the effectiveness of the proposed protocols.     

冲突避免的水声网络拓扑发现协议

当水声网络的所有节点完成在目标区域的部署后,每个节点除了自己的节点ID已知外,对新网络的信息一无所知,而这些信息是网络顺利运行的必要前提。因此,一个能够完成网络中所有节点和链路发现的网络拓扑发现协议是非常必要和重要的。水声拓扑发现协议完成的效率,往往依赖于信道接入策略的选择,但它不能完全使用已有的水声多路访问控制(multiple access control, MAC)协议,因为在网络建立的初始阶段拓扑未知,已有传统水声MAC协议不能完成拓扑发现,所以需要根据这一阶段的特殊状态来设计拓扑发现协议。基于此问题,提出了一种高效的冲突避免的水声网络拓扑发现(简称为CFVE)协议,该协议利用网络中节点ID的唯一性,在其特定时隙接入信道,节点无冲突地发现控制分组的交换,最终实现网络中所有链路和节点的发现。仿真结果表明, CFVE协议可以以较低的发现时延和能耗完成全网拓扑的发现,是一种适合于多跳水声网络的拓扑发现协议。     

一种量化因子自适应学习量化训练算法

深度神经网络因参数量过多而影响嵌入式部署，解决的办法之一是模型小型化（如模型量化，知识蒸馏等）。针对这一问题，提出了一种基于BN（batch normg lization）折叠的量化因子自适应学习的量化训练算法（简称为LSQ-BN算法）。采用单个CNN（convolutional neural）构造BN折叠以实现BN与CNN融合；在量化训练过程中，将量化因子设置成模型参数；提出了一种自适应量化因子初始化方案以解决量化因子难以初始化的问题。实验结果表明：8bit的权重和激活量化，量化模型的精度与FP32预制模型几乎一致；4bit的权重量化和8 bit的激活量化，量化模型的精度损失在3%以内。因此，LSQ-BN是一种优异的模型量化算法。     

拓扑可调无标度网络上的雪堆博弈研究

复杂网络上博弈个体间合作行为的涌现具有重要的现实意义.为了研究无标度网络拓扑结构对合作涌现的影响,结合雪堆博弈模型和比例模仿策略,研究了拓扑结构可调的无标度网络上的博弈动力学演化,具体研究内容为网络的幂律指数、平均度和平均聚类系数与合作密度的关系.仿真结果表明,无标度网络的合作密度与网络度分布的均匀程度正相关,高聚类结构可以有效增强网络上的合作密度,即幂律指数越高,平均聚类系数越小时,合作水平越低;另外,平均度与合作密度呈现非单调关系,存在一个最佳平均度.     

基于组件的安全主动网络仿真模型

分析了主动网络中存在的安全问题,提出了一种增强主动网安全性的方法:通过对数据信源格式的扩充,即为主动信包增加安全域的方式来增加主动网络的安全性。建立了基于组件结构的仿真模型,并通过J-Sim仿真软件对具体实例进行了仿真研究。模型可以研究不同的协议部署方式、不同的拓扑结构、不同的安全策略以及不同的网络性能参数对主动网络性能的影响。     

一种新的环型蓝牙网络拓扑形成协议及仿真

根据采用蓝牙技术的无线ad hoc网络的特点，提出了一种分布式的环型蓝牙网络拓扑形成协议。协议采用合并的思想，将节点快速姐奴成一个环型网络，且新节点可以随时加入网络．协议具有拓扑形成过程延迟低、控制开销小的特点，控制开销复杂度为O（N），且形成了平均微微网个数少、每节点度数低的蓝牙网络，网络中最多包含‘（N-2）／（k-1）’＋1个微微网，至少包含‘N/k’个微微网，节点最大度数为2。基于NS2的仿真实验评估了协议的性能，实验结果验证了协议形成了具较佳性能的环型蓝牙网络。     

QoS-aware multicast routing protocol for Ad hoc networks

1 .INTRODUCTIONA mobile ad hoc network ( MANET) is a multi-hopwireless network formed by a collection of mobilenodes without the intervention of fixedinfrastructure.Because an Ad hoc network is infrastructure-less andself-organized,it is used to provide i mpromptu com-munication facilities in harsh environments . Typicalapplication areas of mobile ad hoc networkinclude bat-tlefields ,emergency search,rescue sites and data ac-quisitionin remote areas . A mobile Ad hoc networkisalso usef…     

基于Kullback-Leibler距离的网络节点一致性排序

在复杂网络中,重要节点比其它节点能更大程度地影响网络的结构与功能.如何评价节点之间的相对重要性,找出重要节点,是一个重要的研究课题.已有的节点重要性评价和排序方法存在一定的局限性.为此,本文综合节点基本属性,依赖网络拓扑特性,提出基于Kullback-Leibler距离的节点一致性排序方法.最后,通过实例分析,验证了本文方法较已有方法在不同类型网络上的有效性和适用性更强.