Optimal Information Update for Energy Harvesting Sensor with Reliable Backup Energy

The timely delivery of status information collected from sensors is critical in many real-time applications, e.g., monitoring and control. In this paper, we consider a scenario where a wireless sensor sends updates to the destination over an erasure channel with the supply of harvested energy and reliable backup energy. We adopt the metric age of information (AoI) to measure the timeliness of the received updates at the destination. We aim to find the optimal information updating policy that minimizes the time-average weighted sum of the AoI and the reliable backup energy cost. First, when all the environmental statistics are assumed to be known, the optimal information updating policy exists and is proved to have a threshold structure. Based on this special structure, an algorithm for efficiently computing the optimal policy is proposed. Then, for the unknown environment, a learning-based algorithm is employed to find a near-optimal policy. The simulation results verify the correctness of the theoretical derivation and the effectiveness of the proposed method.     

论迪尔西形象的可靠性

迪尔西为福克纳笔下众多黑人形象之一，小说中的迪尔西既是作者的真实投射，又是基督的化身，用大爱托起了摇摇欲坠的康普生家族。她集各种美德于一身，是毅力、仁爱与忠心等美德的体现。小说的隐含作者是真实作者的反映，与真实作者是一种双向互动的关系。福克纳本人也把关爱、怜悯、同情和牺牲视作人类的普遍真理。由此可见，迪尔西与作品的隐含作者的思想规范是一致的，是故事的可靠叙述者。     

Worst scenario method in homogenization. Linear case

The paper deals with homogenization of a linear elliptic boundary problem with a specific class of uncertain coefficients describing composite materials with periodic structure. Instead of stochastic approach to the problem, we use the worst scenario method due to Hlaváček (method of reliable solution). A few criterion functionals are introduced. We focus on the range of the homogenized coefficients from knowledge of the ranges of individual components in the composite, on the values of generalized gradient in the places where these components change and on the average of homogenized solution in some critical subdomain. This research was supported by grant No. 201/03/0570 of the Grant Agency of the Czech Republic.     

基于IP可靠组播的多点远程计算机控制系统研究与实现

虚拟网络计算VNC(VirtualNetworkComputing)是AT&T剑桥研究所研究并发布的一种基于internet环境的远程控制软件包,能够在广域网上实现远端计算机的操作,控制安装在远程计算机上的仪器设备,并在控制的同时实时看到远端计算机的屏幕输出.但是VNC软件是建立在TCP协议上的,只能够实现点对点的操作.此文在兼容原有VNC软件基础上,提出了单播-组播代理UMX模型,使用可靠组播技术设计并且实现了VNC-Proxy,使得多个用户能够同时操作连接在远端计算机上的仪器,远端计算机的输出通过单播方式传给VNC-Proxy,再由VNC-Proxy使用可靠组播方式传给各个远端用户.与使用多个单播连接方式实现多点控制比较,基于可靠组播方式的UMX实现大大地减少了网络传输中的带宽占用.     

Delay‐dependent robust reliable control for uncertain switched neutral systems

This article investigates the robust reliable control problem for a class of uncertain switched neutral systems with mixed interval time‐varying delays. The system under study involves state time‐delay, parameter uncertainties and possible actuator failures. In particular, the parameter uncertainties is assumed to satisfy linear fractional transformation formulation and the involved state delay are assumed to be randomly time varying which is modeled by introducing Bernoulli distributed sequences. The main objective of this article is to obtain robust reliable feedback controller design to achieve the exponential stability of the closed‐loop system in the presence of for all admissible parameter uncertainties. The proposed results not only applicable for the normal operating case of the system, but also in the presence of certain actuator failures. By constructing an appropriate Lyapunov–Krasovskii functional, a new set of criteria is derived for ensuring the robust exponential stability of the closed‐loop switched neutral system. More precisely, zero inequality approach, Wirtinger's based inequality, convex combination technique and average dwell time approach are used to simplify the derivation in the main results. Finally, numerical examples with simulation result are given to illustrate the effectiveness and applicability of the proposed design approach. © 2015 Wiley Periodicals, Inc. Complexity 21: 224–237, 2016     

氮气中六氟化硫气体标准物质的研制

建立了制备氮气中六氟化硫气体标准物质的方法。以称量法制备气体标准物质并计算定值,采用气相色谱法对制备的气体标准物质的均匀性和稳定性进行考察。将所制备的标准物质与中国计量院提供的氮气中六氟化硫气体标准物质进行比对分析验证,确保了气体标准物质量值的准确可靠。结果表明,所研制的浓度为10μL/L的氮气中六氟化硫气体标准物质定值的扩展不确定度为2%,贮存有效期为1年,完全能够满足电力部门仪表的检定与校准要求。     

Internet的可靠多媒体多播协议

研讨多媒体多播应用中的允许延迟和分组丢失率问题，提出了一种基于转接节点概念的可靠多播协554(RMPRM)．RMPRM协议聚焦在允许延迟上提供多媒体服务质量保证，转接节点放置在多播树上，数据恢复在两个转接节点之间进行。RMPRM协议转接能满足重传需求和减少分组的复制数量。给出了RMPRM协议与不可靠多播协议的比较。仿真实验表明该协议具有较高的传输率和较低的端到端的传输延迟。研究表明RMPRM协议为多媒体多播传输提供了一种新的有效途径。     

梯形区域极点配置静态输出反馈可靠控制

针对线性系统,考虑连续增益故障模型,研究了具有执行器故障的梯形区域极点配置的静态输出反馈可靠控制问题。首先,在执行器无故障的前提下,给出使极点能够配置在梯形区域内的充分条件,进而得出系统的静态输出反馈可靠控制率。然后,基于执行器故障,重新设计静态输出反馈可靠控制器,利用求解线性矩阵不等式的方法,完成静态输出反馈可靠控制器的设计。由此可靠控制器构成的闭环系统,使得当执行器发生故障时,也可使闭环系统的所有极点保持在梯形区域内。最后的数值仿真验证了结果的有效性和可行性。     

大规模MANET中支持可靠广播的同步MAC协议

为在大规模移动Ad hoc网络(mobile ad hoc network,MANET)中实现可靠的广播传输,提出了一种支持可靠广播的MAC协议RBMP(the reliable broadcast MAC protocol,RBMP)。该协议采用预留分组交互、二次预约等措施保证了在不同网络规模MANET中可靠广播业务传输的实现。仿真结果表明,该协议保证了可靠广播分组的传输,易于实现且开销较小,适用于大规模MANET网络。     

基于可靠组播的实时性信息流传输控制算法

主要讨论实时信息流在可靠组播传输中的控制问题。针对这种信息流对可靠性要求相对较低，但对端到端传输延迟和网络抖动的要求很高，特引入适应这一要求的功能路由器(Power Router)。功能路由器的主要功能是对反馈信息进行汇聚、数据包丢弃的局部恢复，以及当网络拥塞时，选择性的进行丢包。分析结果表明，这种功能路由器的引入使得传输的时延和抖动性有所提高，而且对于网络的拥塞有一定的自动适应能力。