一种基于有向感知模型的传感器节点覆盖算法

覆盖控制作为无线传感器网络中的一个基本问题,反映了传感器网络所能提供的“感知”服务质量.优化传感器网络覆盖对于合理分配网络的空间资源,更好地完成环境感知、信息获取任务以及提高网络生存能力都具有重要的意义.针对无线传感器网络方向个数固定的有向感知模型提出一种覆盖增强算法,采用复杂网络社团结构算法划分对网络进行节点子集划分,重新调整节点的感知方向,增强网络的覆盖率,同时有效降低了算法的时间复杂度.     

Power control for multicell CDMA wireless networks: A team optimization approach

We study power control in multicell CDMA wireless networks as a team optimization problem where each mobile attains at the minimum its individual fixed target SIR level and beyond that optimizes its transmission power level according to its individual preferences. We derive conditions under which the power control problem admits a unique feasible solution. Using a Lagrangian relaxation approach similar to [10] we obtain two decentralized dynamic power control algorithms: primal and dual power update, and establish their global stability utilizing both classical Lyapunov theory and the passivity framework [14]. We show that the robustness results of passivity studies [8, 9] as well as most of the stability and robustness analyses in the literature [10] are applicable to the power control problem considered. In addition, some of the basic principles of call admission control are investigated from the perspective of the model adopted in this paper. We illustrate the proposed power control schemes through simulations. Tansu Alpcan was with the University of Illinois at Urbana-Champaign during this research. X. Fan, M. Arcak, J. T. Wen: Research supported in part by the RPI Office of Research through an Exploratory Seed Grant. John Wen is supported by the China NSFC two-bases project under grant no. 60440420130. T. Başar: Research supported in part by the NSF Grant ITR 00-85917. Tansu Alpcan received the B.S. degree in electrical engineering from Bogazici University, Istanbul, Turkey in 1998. He received the M.S. and Ph.D. degrees in electrical and computer engineering from University of Illinois at Urbana-Champaign (UIUC) in 2001 and 2006, respectively. His research interests include game theory, control and optimization of wired and wireless communication networks, network security, and intrusion detection. He has received Fulbright scholarship in 1999 and best student paper award in IEEE Conference on Control Applications in 2003. He first authored more than 20 journal and conference articles and was an associate editor for IEEE Conference on Control Applications (CCA) in 2005. Tansu is the recipient of the Robert T. Chien Research Award from the UIUC Department of Electrical and Computer Engineering and Ross J. Martin Research Award from the UIUC College of Engineering in 2006. Tansu Alpcan is a (student) member of IEEE since 1998. Currently, he is a post-doctoral research scientist in Deutsche Telekom Laboratories, which is part of Technische Universitat Berlin, in Germany. Xingzhe Fan received the B.E. and M.E. degrees from Tsinghua University, Beijing, China, and the Ph.D. degree from the Electrical, Computer, and Systems Engineering Department, Rensselaer Polytechnic Institute, Troy, NY, in 1998, 2000, and 2004, respectively. He is currently a visiting assistant professor in Universifty of Miami, Miami, FL. His research interests are in nonlinear control and distributed optimization. Tamer Başar is with the University of Illinois at Urbana-Champaign (UIUC), where he holds the positions of the Fredric G. and Elizabeth H. Nearing Endowed Professor of Electrical and Computer Engineering, Center for Advanced Study Professor, and Research Professor at the Coordinated Science Laboratory. He received the B.S.E.E. degree from Robert College, Istanbul, in 1969, and the M.S., M.Phil, and Ph.D. degrees from Yale University during the period 1970–1972. He joined UIUC in 1981 after holding positions at Harvard University and Marmara Research Institute (Turkey). He has published extensively in systems, control, communications, and dynamic games, and has current research interests in modeling and control of communication networks; control over heterogeneous networks; resource allocation, management and pricing in networks; mobile computing; security issues in computer networks; and robust identification, estimation and control. Dr. Basar is the Editor-in-Chief of Automatica, Editor of the Birkhauser Series on Systems & Control, Editor of the Annals of the International Society of Dynamic Games (ISDG), and member of editorial and advisory boards of several international journals in control, wireless networks, and applied mathematics. He has received several awards and recognitions over the years, among which are the Medal of Science of Turkey (1993); Distinguished Member Award (1993), Axelby Outstanding Paper Award (1995), and Bode Lecture Prize (2004) of the IEEE Control Systems Society (CSS); Millennium Medal of IEEE (2000); Tau Beta Pi Drucker Eminent Faculty Award of UIUC (2004); the Outstanding Service Award (2005) and the Giorgio Quazza Medal (2005) of the International Federation of Automatic Control (IFAC); and the Richard E. Bellman Control Heritage Award of the American Automatic Control Council (2006). He is a member of the National Academy of Engineering (of USA), a member of the European Academy of Sciences, a Fellow of IEEE, a Fellow of IFAC, a past president of CSS, and the founding president of ISDG. Murat Arcak is an associate professor of Electrical, Computer and Systems Engineering at the Rensselaer Polytechnic Institute in Troy, NY. He was born in Istanbul, Turkey in 1973. He received the B.S. degree in Electrical and Electronics Engineering from the Bogazici University, Istanbul, in 1996, and the M.S. and Ph.D. degrees in Electrical and Computer Engineering from the University of California, Santa Barbara, in 1997 and 2000, under the direction of Petar Kokotovic. He joined Rensselaer in 2001. Dr. Arcak’s research is in nonlinear control theory and its applications, with particular interest in robust and observer-based feedback designs and in analysis and design of large-scale systems. In these areas he has published over eighty journal and conference papers, and organized several technical workshops. He is a member of SIAM, a senior member of IEEE, and an associate editor for the IFAC journal Automatica. He received a CAREER Award from the National Science Foundation in 2003, and the Donald P. Eckman Award from the American Automatic Control Council in 2006. John Ting-Yung Wen received B.Eng. from McGill University in 1979, M.S. from University of Illinois in 1981, and Ph.D. from Rensselaer Polytechnic Institute in 1985, all in Electrical Engineering. From 1981–1982, he was a system engineer at Fisher Controls where he developed a plant-wide coordination control system for pulp and paper plants. From 1985–1988, he was a member of technical staff at the Jet Propulsion Laboratory where he developed new modeling and control algorithms for large space structures and space robots. Since 1988, he has been with Rensselaer Polytechnic Institute where he is currently a professor in the Department of Electrical, Computer, and Systems Engineering with a joint appointment in the Department of Mechanical, Aerospace, and Nuclear Engineering. Since July 2005, he has been the Director of the Center for Automation Technologies and Systems, a multi-disciplinary research center supported by the New York State. Dr. Wen was an ASEE/NASA Summer Faculty Fellow in 1993, a Japan Society for the Promotion of Science (JSPS) Senior Visiting Scientist in 1997, and has received eleven NASA Tech Brief Awards. His research interest lies in the general area of modeling and control of high performance motion systems, model reduction for complex dynamical systems, and network based control including congestion regulation and multi-robot coordination. Dr. Wen is a Fellow of IEEE.     

Virtual engineering: an integrated approach to agile manufacturing machinery design and control

A virtual manufacturing approach for designing, programming, testing, verifying and deploying control systems for agile modular manufacturing machinery are proposed in this paper. It introduces the concepts, operations, mechanisms and implementation techniques for integrating simulation environments and distributed control system environments so that the control logic programs that have been programmed and verified in the virtual environment can be seamlessly transferred to the distributed control system environment for controlling the real devices. The approach looks to exploit simulation in a much wider range of applications with great advantages in the design and development of manufacturing machine systems. In particular, it facilitates the verification of the runtime support applications using the simulation model before they are applied to the real system. Mechanisms that allow runtime data to be collected during operation of the real machinery to calibrate the simulation models are also proposed. The system implemented delivers a powerful set of software tools for realising agile modular manufacturing systems.     

A general approach to optimal process control

In this paper a general approach to optimal process control is developed, which leads to relatively simple objective functions for optimization. These two features “generality” and “simplicity” are the foundation of the development of powerful approximation techniques which allow simple determination of approximately optimal solutions for a great number of cases.     

A parametric optimization approach to admission control and bandwidth assignment in hybrid TDM networks

The access to a multiservice synchronous TDM network is considered, where hybrid frames are used to carry two basic traffic types (a circuit-switched isochronous and a packet-switched asynchronous one), generated by several users. Each user is assigned a portion of the total available bandwidth, in terms of slots/frame, which is dynamically allocated between the two traffic types at the user premises, by means of a local randomized decision rule. The users' bandwidth shares (capacities) are allocated by a centralized agent, whose goal is to minimize a global cost function that accounts for packet delays and call blocking of the entire process. Parametric optimization problems for the central agent are defined and the application of suitable descent techniques is shown, with the cost function extending over a finite and an infinite time horizon, respectively. The specific nature of the optimization problems is discussed, and numerical examples and simulations are presented that illustrate the effectiveness of the method.     

D-PRMA：一种新的无线Ad Hoc网络资源预留MAC机制

支持资源预留的介质访问控制(MAC)机制是无线ad hoc网络提供服务质量保证的关键.本文在分析分组预留多址接入(PRMA)的基础上,给出了一种新的支持资源预留的无线ad hoc网络MAC机制:分布式PRMA(D-PRMA).D-PRMA的主要特点是分布式的,这适合无线ad hoc网络无中心的特点,同时,D-PRMA具有很短的碰撞持续时间,支持不同速率的实时业务,避免了对分组的分片和重组.通过仿真,本文进一步分析了D-PRMA的性能,仿真结果表明D-PRMA能保证实时业务的带宽和时延.     

SAHRC: 一种基于分簇的无线传感器网络路由控制算法

设计特定应用场合的路由控制算法是无线传感器网络路由控制领域研究的热点之一。在深入研究经典网络路由算法(LEACH)的基础上,提出一种基于分簇的自适应混合型路由控制(SAHRC)算法。该算法针对大规模事件驱动型网络场景应用,采用网内节点启发机制解决了LEACH算法面对大规模网络缺乏自适应性,未考虑节点剩余能量,通信效率难以得到保障等问题。仿真结果表明,新的SAHRC算法比原有LEACH算法有更好的节能性和稳定性。     

TC-BAC: A trust and centrality degree based access control model in wireless sensor networks

Access control is one of the major security concerns for wireless sensor networks. However, applying conventional access control models that rely on the central Certificate Authority and sophisticated cryptographic algorithms to wireless sensor networks poses new challenges as wireless sensor networks are highly distributed and resource-constrained. In this paper, a distributed and fine-grained access control model based on the trust and centrality degree is proposed (TC-BAC). Our design uses the combination of trust and risk to grant access control. To meet the security requirements of an access control system with the absence of Certificate Authority, a distributed trust mechanism is developed to allow access of a trusted node to a network. Then, centrality degree is used to assess the risk factor of a node and award the access, which can reduce the risk ratio of the access control scheme and provide a certain protection level. Finally, our design also takes multi-domain access control into account and solves this problem by utilizing a mapping mechanism and group access policies. We show with simulation that TC-BAC can achieve both the intended level of security and high efficiency suitable for wireless sensor networks.     

A hierarchical fuzzy approach to supervisory control of robot manipulators with oscillatory bases

The research focuses on the issue of controlling a manipulator attached to a deployment, which typically exhibits compliance due to its mechanical nature. The problem is generalized as a motion control of a robotic manipulator attached to oscillatory bases. Due to the complexity of this problem, we decompose the control task into two subtasks and distribute them over two different levels. In the design of hierarchical fuzzy control structure, the lower level controllers take into account each subsystem ignoring the interactions among them, while the upper level controller handles subsystem interactions. The upper level coordinator to deal with the model reduction error and makes the supervisory decision to the lower level. Moreover, the supervisory fuzzy rule set is used to adjust the correction factors of the hierarchical fuzzy controller to achieve better performance. Consequently, it is shown that the proposed control model offers several implementation advantages such as less on-line computation time, reduced effect of overshoot and chattering, and a fast convergent rate in simulation. The results of this study can be feasible to various mechanical systems, such as mobile robot, gantry cranes, underwater robot, and other dynamic systems mounted on oscillatory bases.     

Payload trajectory tracking of a 5-DOF tower crane with a varying-length hoist cable: A passivity-based adaptive control approach

This paper presents a passivity-based adaptive control method for a 5 degree-of-freedom (DOF) tower crane that guarantees robust payload trajectory tracking. The 5-DOF tower crane system considered in this work features three actuated degrees of freedom (including a varying-length hoist cable) and two unactuated degrees of freedom in the hoist cable sway. The proposed controller includes an adaptive feedforward-like control input that is used to ensure that the tower crane features an output strictly passive input–output mapping. The Passivity Theorem is invoked to guarantee closed-loop input–output stability for any output strictly passive negative feedback controller. A novel approach is developed to bound the time derivative of the system’s mass matrix, which is a critical aspect of the proof of passivity. Experimental tests are performed, which demonstrate the effectiveness of the control law on a small-scale three-dimensional tower crane.     

A new approach to power estimation and reduction in CMOS digital circuits

Modelling and optimization of dynamic capacitive power consumption in digital static CMOS circuits, taking into consideration a reason of a gate switching—gate control mode, is discussed in the present paper. The term ‘gate control mode’ means that a number and type of signals applied to input terminals of the gate have an influence on total amount of energy dissipated during a single switching cycle. Moreover, changes of input signals, which keep the gate output in a steady state, can also cause power consumption. Based on this observation, complex reasons of power losses have been considered. In consequence, the authors propose a new model of dynamic power consumption in static CMOS gates. Appropriate parameters’ calculation method for the new model was developed. The gate power model has been extended to logic networks, and consequently a new measure of the circuit activity was proposed. Switching activity, which is commonly used as a traditional measure, characterizes only the number of signal changes at the circuit node, and it is not sufficient for the proposed model. As the power consumption parameters of CMOS are dependent on their control mode, the authors used probability of the node control mode as a new measure of the circuit activity. Based on the proposed model, a procedure of combinational circuit optimization for power dissipation reduction has been developed. The procedure can be included in a design flow, after technology mapping. Results of the power estimation received for some benchmark circuits are much closer to SPICE simulations than values obtained for other methods. So the model proposed in this study improves the estimation accuracy. Additionally, we can save several percent of the consumed energy.     

Fuzzy error governor: A practical approach to counter actuator saturation on flexible joint robots

In this paper, a practical method to counter actuator saturation based on a fuzzy error governor is developed and a complete case study is considered. In addition to good performance, the method has two attracting properties: It does not change the structure of the main controller, and therefore, the theoretically proven characteristics of the system are untouched, and it is simply implementable in practice. The proposed controller structure is applied on a flexible joint robot (FJR). The robust stability of the closed loop system for an n-DOF FJR is thoroughly analyzed and the proposed controller is implemented on a laboratory setup to show the ease of implementation and the resulting closed-loop performance. The main controller used for the n-DOF FJR consists of a composite structure, with a PD controller on the fast dynamics and a PID controller on the slow dynamics. The bandwidth of the fast controller is decreased during critical occasions with the fuzzy logic supervisor, which adjusts the loop gain to a proper level. Using Lyapunov direct method, the robust stability of the overall system is analyzed in presence of modeling uncertainties, and it is shown that if the PD and the PID gains are tuned to satisfy certain conditions, the closed loop system becomes UUB stable.     

A quad-rotor system for driving and flying missions by tilting mechanism of rotors: From design to control

This article presents the hybrid design and control of a quad-rotor system called Flymobile. Flymobile is a combined system of a mobile robot and a quad-rotor system aimed to perform both flying and driving tasks. Flymobile performs flying tasks in the same way as conventional quad-rotor systems while the tilting mechanism of each rotor allows Flymobile to navigate in its terrain for a driving task. The body frame with rotors is implemented by a calibration process through a test-bed equipped with a force sensor. The triangular wheel frame is designed to mimic motions of a mobile robot with three passive wheels. Sensor data of a gyro and an accelerometer are filtered and used for controlling the attitude of the system. Focusing on a practical approach of implementing a hybrid system, a non model-based approach is applied to control Flymobile. Experimental studies are demonstrated to show the feasibility of performing both driving and flying missions.