A minimum energy feedback regulator for systems subject to an average power constraint

An implicitly defined closed-loop version of the minimum energy-average power constrained optimal regulator for linear systems is introduced and its stability analyzed. A design procedure is developed for synthesizing a state-vector feedback controller which approximates this implicit control law. Simulation results are presented for second-and fourth-order systems which illustrate the restraining effects on the control signal.     

基于网络拓扑优化的WSN最小跳路由算法

以节能为主要目标,基于最小跳路由的思想提出一种基于网络拓扑优化的WSN最小跳路由算法——MH-TO算法。该算法采用折半匹配的功率调整策略对网络拓扑进行优化,并引入“塔模型”实现节点的最小跳信息的学习,使得信息包路由时沿着最小跳的路径向sink节点传送。理论分析和仿真实验结果表明,与基于最小跳数场的自组织路由算法相比,该算法能够降低能量消耗并均衡能量负载,从而显著延长网络的生存期。     

Adaptive one-step-ahead control subject to an input-amplitude constraint

This paper investigates the adaptive control of a single-input/single-output process when there exists a constraint on the amplitude of the applied control signal. In particular, an adaptive control scheme is proposed and is shown to be globally convergent in the sense that the control asymptotically matches the amplitude-constrained one-step-ahead optimal control. Some simulation results are presented to demonstrate the performance of the scheme     

Reliability evaluation of a multistate network subject to time constraint under routing policy

A multistate network is a stochastic network composed of multistate arcs in which each arc has several possible capacities and may fail due to failure, maintenance, etc. The quality of a multistate network depends on how to meet the customer's requirements and how to provide the service in time. The system reliability, the probability that a given amount of data can be transmitted through a pair of minimal paths (MPs) simultaneously under the time constraint, is a proper index to evaluate the quality of a multistate network. An efficient solution procedure is first proposed to calculate it. In order to further enhance the system reliability, the network administrator decides the routing policy in advance to indicate the first and the second priority pairs of MPs. The second priority pair of MPs takes charge of the transmission duty if the first fails. The system reliability under the routing policy can be subsequently evaluated.     

Minimum weight design of a rectangular panel subject to a flutter speed constraint

The thickness distribution for a simply supported rectangular panel is determined for minimum panel weight and a specified aeroelastic eigenvalue. Finite difference equations are used for derivatives with respect to the spanwise variable so that the partial differential constraint equations are approximated by sets of ordinary differential equations. Numerical solutions are obtained for the resulting optimal control problem using a gradient projection algorithm.     

事件驱动型无线传感器网络最小时延路由协议

针对事件驱动型无线传感器网络对时延性能的要求,提出了一种最小时延路由(MDR)协议.该协议利用RTS/CTS消息机制建立路由,避免了复杂的路由算法所带来计算开销,并在此基础上通过控制节点的下一跳可达区域的子区域的数量和对应的后退窗口时间长度来最小化节点的感应数据包到达汇聚节点的时延.实验结果表明:所提路由协议有效提高了事件驱动型传感器网络的时延性能.     

The message flow model for routing in wormhole-routed networks

In this paper, we introduce a new approach to deadlock-free routing in wormhole-routed networks called the message flow model. This method may be used to develop deterministic, partially-adaptive, and fully-adaptive routing algorithms for wormhole-routed networks with arbitrary topologies. We first establish the necessary and sufficient condition for deadlock free routing, based on the analysis of the message flow on each channel. We then use the model to develop new adaptive routing algorithms for 2D meshes     

无线传感器网络中平均时延约束的自适应休眠机制

针对流量动态变化的无线传感器网络,提出了具有平均时延约束的自适应休眠机制.在休眠阶段,节点采取自适应地周期性休眠和苏醒来节省能量且保证平均传输延迟.在苏醒周期的节点没有数据发送或者收到目的地址为其他节点的RTS/CTS帧后进入休眠周期.通过建立马尔科夫链模型分析可得到该机制中平均时延约束下休眠周期的优化值.     

用于MPLS流量工程的最小延时和最小干扰路由算法

借鉴最小干扰路由算法(MIRA)的思想,提出一种最小延时和最小干扰路由算法MDMI,以实现用于多协议标签交换(MPLS)流量工程的服务质量(QoS)路由方案。该算法首先选择k条最小时延备选路由,然后通过网络流计算避开关键链路选路。该算法在实现负载均衡、提高网络资源利用效率的同时提供了一种延时控制方式。仿真结果表明,该算法以k倍时间复杂度提升为代价,在满足标签转发路径(LSP)请求和资源利用率方面能达到较好的性能。     

Minimal spanning tree subject to a side constraint

This paper addresses the problem of finding a minimal spanning tree in a network subject to a knapsack-type constraint. The problem is shown to belong to the class of NP -complete problems. Certain properties of an optimal solution to this problem are established considering a bicriteria spanning tree problem. Based on these, an algorithm is proposed which is mainly a branch and bound scheme branching from the test upper bound and generating efficient frontiers successively. It also uses certain effective heuristics and bounds that are obtained in polynomially bounded operations. The algorithm is validated and a numerical example is included.     

Direct adaptive control subject to input amplitude constraint

This paper deals with the problem of controlling discrete-time linear systems with unknown dynamics and a saturation-type constraint on the control input amplitude. We propose a direct adaptive regulator that globally stabilizes any system with one pole at x=1 and all others inside the unit disk. The regulator design is carried out using the pole placement technique. Of particular interest, the input saturation vanishes after a finite transient period     

Robust pole assignment in systems subject to structured perturbations

The problem of robust pole assignment by feedback in a linear, multivariable, time-invariant system which is subject to structured perturbations is investigated. A measure of robustness, or sensitivity, of the poles to a given class of perturbations is derived, and a reliable and efficient computational algorithm is presented for constructing a feedback which assigns the prescribed poles and optimizes the robustness measure.     

延迟的多径路由协议的改进

Ad hoc网络中多径路由算法因其表现出的较好性能受到人们越来越多的关注。但多径路由依旧采用“最小跳数”路由选择机制。很多研究显示最小跳数并不能提供最小的端到端时延保证。采用跨层设计思想,在路由选择机制中引入最短队列长度参数,提出了一种基于延迟的多路径路由算法QAOMDV。仿真结果表明QAOMDV算法可以降低端到端的传输时延,提高数据包的投递率,改善了网络性能。     

Near-optimal message routing and broadcasting in faulty hypercubes

A distributed routing algorithm for faulty hypercubes is described. This algorithm uses a directed depth-first approach to find a path between the sender and receiver of a message whenever at least one non-faulty path exists. We show that, when an arbitrary number of elements of the hypercube can be faulty, the algorithm always routes messages using fewer than 2N hops, whereN is the number of nodes in the hypercube. This performance is shown to be within a factor of two of the optimal worst-case routing efficiency. Through foult simulations, we show that, even when up to half of the elements in the cube are faulty, complete the analysis, we prove that our algorithm is deadlock-free. Finally, we present two extensions of the algorithm. The first uses local storage to reduce the overhead of the algorithm while the second allows reliable broadcasting in the presence of an arbitrary number of faults.Supported in part by the National Science Foundation under Grant CCR-9010547.Supported in part by the National Science Foundation Instrumentation Grant CDA-8820627.     

一类带有加速度约束的非线性系统最优滑模控制

针对加速度受约束的非线性时变系统,设计了一种全局最优滑模控制算法.首先引入全程滑态因子,保证滑模面一开始就在零值附近,然后选取位置跟踪误差绝对值的积分为指标函数,通过求解该指标函数的最小值来确定滑模面方程的相关参数,最后设计了基于指数趋近律的滑模控制算法.仿真结果表明了该方法的有效性和强鲁棒性.     

容迟网络中传染路由协议优化

针对传染路由协议（EPI）的泛洪机制会造成容迟网络资源浪费的问题,提出将节点间的历史相遇信息引入传染路由协议的改进算法（EPI-HT）,以达到准确选择数据下一跳转发节点的目的。仿真结果表明,改进后的EPI-HT比EPI明显抑制了数据泛洪传输,可提高交付率,同时降低端到端时延。     

Integrating dock-door assignment and vehicle routing with cross-docking

This paper presents an integrated cross-dock door assignment and vehicle routing problem arising in the operation of cross-dock terminals. It consists of assigning origins to inbound doors, transferring commodities between doors, and routing vehicles from outbound doors to destinations. The objective is to jointly minimize the total material handling and transportation costs. Two formulations of the problem are presented and computationally compared. In addition, we develop a column generation algorithm based on the most promising formulation and a heuristic to obtain lower and upper bounds for the optimal solution of the problem, respectively. Numerical results on a set of benchmark instances with up to 20 origins and 50 destinations confirm the efficiency of the proposed solution algorithms.     

Distributed directory service and message routing for mobile agents

Research about networks and agents has identified the need for a layer that provides a uniform protocol to communicate with fixed and mobile agents. In order to preserve the compatibility with existing infrastructures, proposed solutions have involved a “home agent”, which forwards messages to a mobile entity. The mechanism of a home agent puts a burden on the infrastructure, which may hamper the scalability of the approach, in particular, in massively distributed systems, such as the amorphous computer or the ubiquitous/pervasive computing environment. Free from any compatibility constraint, we have designed an algorithm to route messages to mobile agents that does not require any fixed location. The algorithm has two different facets: a distributed directory service that maintains distributed information about the location of a mobile agent, and a message router that uses the directory service to deliver messages to a mobile agent. Two properties of the algorithm were established. Safety ensures that messages are delivered to the agent they were aimed at, whereas liveness guarantees that messages eventually get delivered. A mechanical proof of the properties was carried out using the proof assistant Coq.     

Robust discrete-time adaptive control subject to a control input amplitude constraint

Subject to a control input amplitude constraint, an adaptive algorithm is proposed to control discrete-time plants with unmodelled dynamics. By introducing an additional feedback signal, it is shown that the uniform boundedness of all signals in the adaptive loop can be guaranteed. The nominal plant is assumed to be stable but unnecessarily minimum phase. Various properties of this adaptive algorithm are analysed. It is shown that the performance which can be achieved with no control input amplitude constraint in the non-adaptive case (i.e. the case when the true nominal plant is known a priori) is asymptotically well maintained in the adaptive system. The analysis is supported by computer simulation results.     

Induction of rules subject to a quality constraint: probabilisticinductive learning

Organizational databases are being used to develop rules or guidelines for action that are incorporated into decision processes. Tree induction algorithms of two types, total branching and subset elimination, used in the generation of rules, are reviewed with respect to their treatment of the issue of quality. Based on this assessment, a hybrid approach, probabilistic inductive learning (PrIL), is presented. It provides a probabilistic measure of goodness for an individual rule, enabling the user to set maximum misclassification levels, or minimum reliability levels, with predetermined confidence that each and every rule will satisfy this criterion. The user is able to quantify the reliability of the decision process, i.e., the invoking of the rules, which is of crucial importance in automated decision processes. PrIL and its associated algorithm are described. An illustrative example based on the claims process at a workers' compensation board is presented