检索结果-南通市图书馆

TCP Issues in Mobile Ad Hoc Networks： Challenges and Solutions

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2006年第1期21卷 72-81页

作者：徐伟强吴铁军 institute of intelligent systems & decision making Zhejiang University Hangzhou 310027 P.R. China

Mobile ad hoc networks （MANETs） are a kind of very complex distributed communication systems with wireless mobile nodes that can be freely and dynamically self-organized into arbitrary and temporary network topologies. MANETs inherit several limitations of wireless networks, meanwhile make new challenges arising from the specificity of MANETs, such as route failures, hidden terminals and exposed terminals. When TCP is applied in a MANET environment, a number of tough problems have to be dealt with. In this paper, a comprehensive survey on this dynamic field is given. Specifically, for the first time all factors impairing TCP performance are identified based on network protocol hierarchy, i.e., lossy wireless channel at the physical layer; excessive contention and unfair access at the MAC layer; frail routing protocol at the network layer, the MAC layer and the network layer related mobile node; unfit congestion window size at the transport layer and the transport layer related asymmetric path. How these factors degrade TCP performance is clearly explained. Then, based on how to alleviate the impact of each of these factors listed above, the existing solutions are collected as comprehensively as possible and classified into a number of categories, and their advantages and limitations are discussed. Based on the limitations of these solutions, a set of open problems for designing more robust solutions is suggested.

关键词： mobile ad hoc network TCP route failure node mobility cross-layer design

Delay-dependent robust H∞ control for a class of uncertain switched systems with time delay

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Zhejiang University Science 2004年第7期5卷 841-850页

作者：师佳吴铁军杜树新 National Key Lab for Industrial Control Technology Institute of Intelligent Systems and Decision MakingZhejiang UniversityHangzhou 310027China

For linear switched system with both parameter uncertainties and time delay, a delay-dependent sufficient condition for the existence of a new robust H∞ feedback controller was formulated in nonlinear matrix inequalities solvable by an LMI-based iterative algorithm. Compared with the conventional state-feedback controller, the proposed controller can achieve better robust control performance since the delayed state is utilized as additional feedback information and the parameters of the proposed controllers are changed synchronously with the dynamical characteristic of the system. This design method was also extended to the case where only delayed state is available for the controller. The example of balancing an inverted pendulum on a cart demonstrates the effectiveness and applicability of the proposed design methods.

关键词： Linear switched systems Robust H∞ control Matrix inequality Time delay

A multi-UAV deployment method for border patrolling based on Stackelberg game

在线全文

学校读者我要写书评

暂无评论

Journal of systems Engineering and Electronics 2023年第1期34卷 99-116页

作者： LEI Xing HU Xiaoxuan WANG Guoqiang LUO He School of Management Hefei University of TechnologyHefei 230009China Key Laboratory of Process Optimization&intelligent decision-making Ministry of EducationHefei 230009China Engineering Research Center for intelligent decision-making&Information systems Technologies Ministry of EducationHefei 230009China

To strengthen border patrol measures, unmanned aerial vehicles(UAVs) are gradually used in many countries to detect illegal entries on borders. However, how to efficiently deploy limited UAVs to patrol on borders of large areas remains challenging. In this paper, we first model the problem of deploying UAVs for border patrol as a Stackelberg game. Two players are considered in this game: The border patrol agency is the leader,who optimizes the patrol path of UAVs to detect the illegal immigrant. The illegal immigrant is the follower, who selects a certain area of the border to pass through at a certain time after observing the leader’s strategy. Second, a compact linear programming problem is proposed to tackle the exponential growth of the number of leader’s strategies. Third, a method is proposed to reduce the size of the strategy space of the follower. Then, we provide some theoretic results to present the effect of parameters of the model on leader’s utilities. Experimental results demonstrate the positive effect of limited starting and ending areas of UAV’s patrolling conditions and multiple patrolling altitudes on the leader ’s utility, and show that the proposed solution outperforms two conventional patrol strategies and has strong robustness.

关键词： border patrol unmanned aerial vehicle(UAV) Stackelberg game compact linear programming dominated strategy elimination

Optimization of communication topology for persistent formation in case of communication faults

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2023年第7期32卷 610-624页

作者：王国强罗贺胡笑旋台建玮 School of Management Hefei University of TechnologyHefei 230009China Key Laboratory of Process Optimization&intelligent decision-making Ministry of EducationHefei 230009China Engineering Research Center for intelligent decision-making&Information systems Technologies Ministry of EducationHefei 230009China

To address the optimization problem of communication topology for persistent formation in the case of communication faults such as link interruption,transmitter failure,and receiver failure a two-stage model including fast reconstruction of communication topology and re-optimization of communication topology is ***,a fast reconstruction algorithm of communication topology for persistent formation(FRA-CT-PF),based on optimally rigid graph,arc addition operation,and path reversal operation,is proposed,which can quickly generate a feasible reconstructed communication topology after communication faults,thus ensuring the safety of the agents and maintaining the formation shape of persistent ***,a re-optimization algorithm of communication topology for persistent formation(ROA-CTPF),based on agent position exchange,is proposed,which can further obtain a reoptimized communication topology to minimize the formation communication cost while still maintaining the formation shape of persistent *** time complexities of these two algorithms are also ***,the effectiveness of the above algorithms is verified by numerical *** with existing algorithms,FRA-CT-PF can always obtain feasible reconstructed communication topology in much less time under all communication fault scenarios,and ROA-CT-PF can obtain a reoptimized communication topology to further reduce the formation communication cost in a shorter time.

关键词： persistent formation communication topology formation communication cost communication fault

Optimal coordinated voltage control of power systems

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第2期7卷 257-262页

作者：李艳君 HILL David J 吴铁军 institute of intelligent systems and decision making Zhejiang University Hangzhou 310027 China Department of Electronic Engineering City University of Hong Kong Hong Kong China

An immune algorithm solution is proposed in this paper to deal with the problem of optimal coordination of local physically based controllers in order to preserve or retain mid and long term voltage stability. This problem is in fact a global coordination control problem which involves not only sequencing and timing different control devices but also tuning the parameters of controllers. A multi-stage coordinated control scheme is presented, aiming at retaining good voltage levels with minimal control efforts and costs after severe disturbances in power systems. A self-pattem-recognized vaccination procedure is developed to transfer effective heuristic information into the new generation of solution candidates to speed up the convergence of the search procedure to global optima. An example of four bus power system case study is investigated to show the effectiveness and efficiency of the proposed algorithm, compared with several existing approaches such as differential dynamic programming and tree-search.

关键词： Power systems Voltage control Immune algorithm Global optimization

Optimal fusion estimation for stochastic systems with cross-correlated sensor noises

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2017年第12期60卷 57-70页

作者： Liping YAN Yuanqing XIA Mengyin FU School of Automation Key Laboratory of Intelligent Control and Decision of Complex SystemsBeijing Institute of Technology

This paper is concerned with the optimal fusion of sensors with cross-correlated sensor *** taking linear transformations to the measurements and the related parameters, new measurement models are established, where the sensor noises are decoupled. The centralized fusion with raw data, the centralized fusion with transformed data, and a distributed fusion estimation algorithm are introduced, which are shown to be equivalent to each other in estimation precision, and therefore are globally optimal in the sense of linear minimum mean square error(LMMSE). It is shown that the centralized fusion with transformed data needs lower communication requirements compared to the centralized fusion using raw data directly, and the distributed fusion algorithm has the best flexibility and robustness and proper communication requirements and computation complexity among the three algorithms(less communication and computation complexity compared to the existed distributed Kalman filtering fusion algorithms). An example is shown to illustrate the effectiveness of the proposed algorithms.

关键词： optimal estimation distributed fusion Kalman filter cross-correlated noises linear transformation

Adaptive unscented Kalman filter for parameter and state estimation of nonlinear high-speed objects

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of systems Engineering and Electronics 2013年第4期24卷 655-665页

作者： Fang Deng Jie Chen Chen Chen School of Automation Beijing Institute of Technology Key Laboratory of intelligent Control and decision of Complex systems

An adaptive unscented Kalman filter （AUKF） and an augmented state method are employed to estimate the timevarying parameters and states of a kind of nonlinear high-speed objects. A strong tracking filter is employed to improve the tracking ability and robustness of unscented Kalman filter （UKF） when the process noise is inaccuracy, and wavelet transform is used to improve the estimate accuracy by the variance of measurement noise. An augmented square-root framework is utilized to improve the numerical stability and accuracy of UKF. Monte Carlo simulations and applications in the rapid trajectory estimation of hypersonic artillery shells confirm the effectiveness of the proposed method.

关键词： parameter estimation state estimation unscented Kalman filter (UKF) strong tracking filter wavelet transform.

Adaptive Robust Dead-Zone Compensation Control of Electro-Hydraulic Servo systems with Load Disturbance Rejection

在线全文

学校读者我要写书评

暂无评论

Journal of systems Science & Complexity 2015年第2期28卷 341-359页

作者： HE Yudong WANG Junzheng HAO Renjian Key Laboratory of intelligent Control and decision of Complex systems School of AutomationBeijing Institute of Technology

A backstepping method based adaptive robust dead-zone compensation controller is pro- posed for the electro-hydraulic servo systems （EHSSs） with unknown dead-zone and uncertain system parameters. Variable load is seen as a sum of a constant and a variable part. The constant part is regarded as a parameter of the system to be estimated real time. The variable part together with the friction are seen as disturbance so that a robust term in the controller can be adopted to reject them. Compared with the traditional dead-zone compensation method, a dead-zone compensator is incor- porated in the EH$S without constructing a dead-zone inverse. Combining backstepping method, an adaptive robust controller （ARC） with dead-zone compensation is formed. An easy-to-use ARC tuning method is also proposed after a further analysis of the ARC structure. Simulations show that the proposed method has a splendid tracking performance, all the uncertain parameters can be estimated, and the disturbance has been rejected while the dead-zone term is well estimated and compensated.

关键词： Adaptive robust control dead-zone servo systems tuning method. compensation disturbance rejection electro-hydraulic

A-STC: auction-based spanning tree coverage algorithm for motion planning of cooperative robots

在线全文

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2019年第1期20卷 18-31页

作者： Guan-qiang GAO Bin XIN School of Automation Beijing Institute of Technology Key Laboratory of intelligent Control and decision of Complex systems Beijing Advanced Innovation Center for intelligent Robots and systems

The multi-robot coverage motion planning(MCMP) problem in which every reachable area must be covered is common in multi-robot systems. To deal with the MCMP problem, we propose an efficient, complete, and off-line algorithm, named the "auction-based spanning tree coverage(A-STC)" algorithm. First, the configuration space is divided into mega cells whose size is twice the minimum coverage range of a robot. Based on connection relationships among mega cells, a graph structure can be obtained. A robot that circumnavigates a spanning tree of the graph can generate a coverage trajectory. Then, the proposed algorithm adopts an auction mechanism to construct one spanning tree for each robot. In this mechanism, an auctioneer robot chooses a suitable vertex of the graph as an auction item from neighboring vertexes of its spanning tree by heuristic rules. A bidder robot submits a proper bid to the auctioneer according to the auction vertexes' relationships with the spanning tree of the robot and the estimated length of its trajectory. The estimated length is calculated based on vertexes and edges in the spanning tree. The bidder with the highest bid is selected as a winner to reduce the makespan of the coverage task. After auction processes, acceptable coverage trajectories can be planned rapidly. Computational experiments validate the effectiveness of the proposed MCMP algorithm and the method for estimating trajectory lengths. The proposed algorithm is also compared with the state-of-the-art algorithms. The comparative results show that the A-STC algorithm has apparent advantages in terms of the running time and the makespan for large crowded configuration spaces.

关键词： Coverage motion planning Multi-robot system Auction algorithm Spanning tree coverage algorithm