D-LDA：一种分布式单向时延测量方法

为了测量数据中心网络的单向时延,针对数据中心网络高带宽低延迟的特点,提出了分布式有损差分聚合( Dis-tributed Lossy Difference Aggregator,D-LDA)测量方法。该方法在有损差分聚合算法的基础上,能够测量网络中任意端到端的单向时延,并且增强了对大数据量报文的处理能力,且架构灵活,扩展性好。开发了实际的测量系统进行实验,系统采用FourInOne分布式框架和基于Java的B/S架构。测试结果显示该方法计算效率高,CPU占用率低,占用带宽小,可以广泛地用于数据中心网络进行性能监测。     

一种相控阵超声波检测系统的实现方法

常规超声相控阵检测方法由于不断进行硬件变焦,会带来采集时间长、数据量大及对数据采集卡采样率要求过高等缺点.为解决上述问题,根据相控阵的基本原理,提出一种改进方案,采用多通道切换、无角度扫描和软件延时等方法,构建了一套非实时超声相控阵数据采集系统,利用软件变焦代替硬件变焦,增强缺陷信号性噪比、提高缺陷识别率的同时,改善超声相控阵检测的时效性和经济性.最后通过该系统对含缺陷试块进行实际验证试验,成功找出试块中的缺陷位置,结果与实际情况相符.     

开放式网络控制系统仿真平台的研究与开发

分析了几种网络控制系统仿真平台的工作原理,在总结它们各自的优劣后,结合参与开发的一套现场总线控制系统,进一步开发出了基于工业以太网的网络控制系统仿真平台.上述平台能够真实再现工业现场网络环境,除被控对象采用数值程序模拟外,各功能节点均采用真实的物理节点,能够适应不同对象的仿真需求,并且网络规模易于调整、外部数据导入方便.仿真结果表明,在上述平台上进行网络控制系统仿真研究是有效的、正确的.     

基于声传感器阵列的机器人语音定向技术研究

将声源定向技术应用于机器人平台,使其对语音信号具有感知定向能力。对语音定向技术的3个阶段进行仿真,首先进行语音端点检测,然后解算2只声传感器间的时间延迟,最后结合声传感器阵列的空间几何结构分析定向误差。仿真结果表明:算法简单有效,能有效减少系统计算量,具备一定抗噪声和混响能力,满足系统定向精度的要求,对工程实现有一定指导意义。     

基于信号完整性分析的TPM芯片设计

由于可信计算平台自身的设计原理及机制上的缺陷,其在面对物理攻击时很难有效地保护整个平台系统的安全性,而基于信号完整性分析的TPM芯片设计思想已给出了较好的解决方案.在上述研究工作的基础上,进一步提出了逻辑分层的TPM-APM（TPM-analog parameter measurement）子模块改进设计方案.通过对时延模拟参数的度量,给出了TPM芯片中TPM-APM子模块的工程实现方法,并使用眼图比对法,为TPM-APM子模块实现的可行性进行了验证.分析结果表明,引入改进设计的TPM-APM子模块可增强可信计算平台面对物理攻击时的防御能力.     

通信受限网络控制系统的H∞ 控制

针对一类通信受限的网络控制系统,研究其随机稳定性和 ∞控制问题.考虑到系统存在随机丢包、时延、对数量化和概率传感器故障等因素,提出一种新的网络控制系统模型.基于Lyapunov稳定性理论,得到了系统随机稳定性的充分条件,并利用线性矩阵不等式技术,给出了系统 ∞控制器的设计方法.数值仿真算例验证了所得结论的有效性.     

On a geometric characterisation of zeros for non-square linear systems with time-delay in state

The concept of invariant zeros in a linear time-invariant system with point delay in state vector is discussed in the state space framework. These zeros are treated as the triples: complex number, non-zero state-zero direction and input-zero direction. Such treatment is strictly related to the output-zeroing problem and in that spirit the zeros can be easily interpreted. As is shown, for systems with matrix CB of full row-rank, general formulas for output-zeroing inputs can be obtained as well as a characterisation of invariant zeros as the roots of a certain quasi-polynomial can be given. The question of degeneracy/non-degeneracy of the system is also addressed. Moreover, it is shown that diagonal decoupling can be achieved by constant state feedbacks and a pre-compensator. The transfer matrix of the decoupled system is square and does not contain delay. The mathematical tools used in the analysis are the Moore–Penrose pseudo-inverse and singular value decomposition of a matrix.     

Hankel-norm model approximation for LPV systems with parameter-varying time delays

This article is concerned with Hankel-norm model approximation (HNMA) for linear parameter-varying systems with parameter-varying time delays. For a given stable system, our attention is focussed on the construction of reduced-order models, which approximate the original system well in a Hankel-norm sense. By applying the slack matrix approach, a delay-dependent sufficient condition is proposed for the robustly asymptotic stability with a Hankel-norm error performance for the error system. Then, the HNMA problem is solved by using the projection approach, which casts the model approximation into a sequential minimisation problem subject to linear matrix inequality constraints by employing the cone complementary linearisation algorithm. Finally, a numerical example is provided to illustrate the effectiveness of the proposed methods.     

Robust adaptive fault-tolerant control for time delay uncertain nonlinear systems with time-varying performance bounds

In this paper, a robust adaptive fault tolerant controller guaranteeing with time-varying performance bounds is designed for a class of time delay uncertain nonlinear systems subject to actuator failures and external disturbance. The influence of time delay on the system is mitigated and the system performance can be guaranteed by introducing a positive nonlinear control gain function and the generalised restricted potential function. A new method with more design degrees of freedom is developed to ensure the norm of the system state within a-priori, user-defined time varying performance bounds. Using the online estimation information provided by adaptive mechanism, a robust adaptive fault-tolerant control method guaranteeing time varying performance bounds is proposed. It is shown that all the signals of the resulting closed-loop system are bounded and the system state less than a-priori, user-defined performance bounds. Finally, simulation results are given to demonstrate the efficacy of the proposed fault-tolerant control method.     

Inventory model with two rates of production for deteriorating items with permissible delay in payments

Some decentralized smoothing problems are solved by applying a forward-pass fixed-interval smoother formula in discrete-time systems. It is assumed that a simple estimation structure consists of a global processor and of two local processors. Two cases are considered for the problems of decentralized smoothing and smoothing update: when the local backward-pass information filtered estimates are available, and when the local-smoothed estimates are available. Some features of present algorithms are discussed from the point of view of data transmissions and numerical computations, etc.