Probabilistic‐constrained filtering for a class of nonlinear systems with improved static event‐triggered communication

This paper is concerned with the probabilistic‐constrained filtering problem for a class of time‐varying systems with stochastic nonlinearities and state constraints. An improved static event‐triggering scheme is used to reduce unnecessary signal transmissions on the communication channel, where a time‐varying triggering parameter is designed according to engineering practice. The aim of the problem addressed is to design a time‐varying filter such that (1) the prescribed probabilistic constraints on the estimation error are satisfied (ie, the probability for the estimation error to be confined to the given ellipsoidal set is larger than a prescribed value) and (2) the ellipsoid is minimized at each time instant in the sense of the matrix norm. First, the probabilistic constraints are handled by means of the multidimensional Chebyshev bounds. By using recursive matrix inequalities, stochastic analysis is conducted to establish sufficient conditions for the existence of the desired probabilistic‐constrained filter. Then, a recursive optimization algorithm is proposed to design the filter gain matrices. Finally, a simulation example is proposed to demonstrate the effectiveness and applicability of the proposed method.     

Dynamic intermittent Q‐learning–based model‐free suboptimal co‐design of ‐stabilization

This paper proposes an intermittent model‐free learning algorithm for linear time‐invariant systems, where the control policy and transmission decisions are co‐designed simultaneously while also being subjected to worst‐case disturbances. The control policy is designed by introducing an internal dynamical system to further reduce the transmission rate and provide bandwidth flexibility in cyber‐physical systems. Moreover, a Q‐learning algorithm with two actors and a single critic structure is developed to learn the optimal parameters of a Q‐function. It is shown by using an impulsive system approach that the closed‐loop system has an asymptotically stable equilibrium and that no Zeno behavior occurs. Furthermore, a qualitative performance analysis of the model‐free dynamic intermittent framework is given and shows the degree of suboptimality concerning the optimal continuous updated controller. Finally, a numerical simulation of an unknown system is carried out to highlight the efficacy of the proposed framework.     

Event‐triggered output consensus for heterogeneous multiagent systems with fixed and switching directed topologies

This paper studies the event‐triggered output consensus problem of heterogeneous linear multiagent systems characterized via fixed and switching directed graphs. With proper state‐dependent triggering functions, two new event‐triggered output consensus control schemes are proposed for each agent to achieve consensus. Notably, under the proposed control protocols, continuous communication among agents is not required in both controllers updating and triggering threshold detection, which means being completely continuous communication free. The communication instances are reduced significantly, and the periodic or high‐frequency communication is restrained. It is also ensured that events cannot be triggered infinitely in finite time (ie, the Zeno behavior is elegantly avoided). Meanwhile, the simulation examples are given to illustrate the theoretical analysis.     

基于双向图算法的快速部分汉语语法分析器

本文给出了一个用双向图算法实现的快速部分汉语语法分析器。为了实现真实文本的快速部分语法分析，分析器使用ＦＩＲＳＴ分析表和ＬＡＳＴ分析表来更大程度地避免创建不必要的活动弧，并且引进了弧的竞争机制和对于一些情况的处理方法，使用了各种分析策略的分析器的准确率达到８７．２％，在主频６６ＭＨｚ的４８６机型上运行速度是３２句／分。     

KCZ6三相整流触发电路应用方法的改进

本文在上海电器科学研究所研制的KCZ6三相整流触发电路的基础上,通过改进设计,实现和完善了“脉冲封锁”功能,增加了“截压截流”功能,这项改进设计进一步提高了三相整流的可靠性和安全性。     

基于LabVIEW的恒周期过零触发电路的分析

分析恒周期过零触发电路的工作原理和输出功率，并利用LabVIEW图形化编程语言进行了频谱分析。实践结果表明，恒周期过零触发电路对电源污染少，负载易于获得良好的正弦波。     

浅谈电子服务系统的应用

本文提出一种集安全防范、电器控制为一体的电子服务系统,它适合于独立的或物业管理的居民住宅。经调试证明,该系统稳定可靠,是住宅自动化管理的优选产业。     

计算机技术在大功率整流装置中的应用

对照原整流控制装置介绍了由株洲四方电力电子有限公司研制的、黑龙江齐化化工有限责任公司2001年10月新投运的RICS系列晶闸管整流装置计算机控制系统的应用。     

Ductile to brittle transition of an A508 steel characterized by Charpy impact test: Part I: experimental results

This study is devoted to the ductile-brittle transition behavior of a French A508 Cl3 (16MND5) steel. Due to its importance for the safety assessment of PWR vessels, a full characterization of this steel with Charpy V-notch test in this range of temperature was undertaken. The aim of this study is to provide a wide experimental database and microstructural observations to supply, calibrate and validate models used in a local approach methodology. Mechanical and fracture properties of the steel have been investigated over a wide range of temperatures and strain-rates. Effects of impact velocity on ductile-brittle transition curve, on ductile tearing and on notch temperature rise are presented and discussed. A detailed study of ductile crack initiation and growth in Charpy specimens is also carried out. From fractographic investigations of the microvoids nucleation around carbide second phase particles, a plastic strain threshold for nucleation is determined for this material. A508 Cl3 steels undergo a transition in fracture toughness properties with temperature, due to a change in fracture mode from microvoids coalescence to cleavage fracture. A systematic investigation on the nature and the position of cleavage triggering sites and on any change in the ductile to brittle transition (DBT) range has been carried out. This leads to the conclusion that manganese sulfide inclusions do not play an increasing role with increasing test temperature as recently mentioned in other studies on A508 Cl3 steel with a higher sulfur content. In a companion paper [Tanguy et al., Engng. Fract. Mech., in press], the numerical simulation of the Charpy test in the ductile-brittle transition range using fully coupled local approach to fracture is presented.     

Fluke ScopeMeter 190C的脉冲触发功能

F1uke公司的ScopeMeter 190C手持示波器利用其先进的脉冲触发功能能将所有诊断功能集成在工程师的掌上。本文介绍了为何脉冲宽度触发功能可以用来进行很多单边的触发功能所不能进行的诊断。