Adaptive observers for time-delay nonlinear systems in triangular form

A simple nonlinear observer with a dynamic gain is proposed for a class of bounded-state nonlinear systems subject to state delay. By saturating the states of the observer nonlinearities with either symmetric or non-symmetric saturation functions, we show that the observer exists, whatever the delay is. Furthermore, it will be highlighted that the observer design is free from any preliminary analysis of the time-delay system such as estimating the Lipschitz constants of nonlinearities. The proposed design encompasses a wide class of nonlinear and time-delay systems written in triangular form and generalizes previous results on delayless nonlinear systems.     

An eigenvalue based approach for the stabilization of linear time-delay systems of neutral type

An eigenvalue based approach for the stabilization of linear neutral functional differential equations is presented, which extends the recently developed continuous pole placement method for delay equations of retarded type. The approach consists of two steps. First the stability of the associated difference equation is determined and a procedure is applied to compute the supremum of the real parts of its characteristic roots, which corresponds to computing the radius of the essential spectrum of the solution operator of the neutral equation. No restrictions are made on the dimension of the system and the number of delays. Also the effect of small delay perturbations is explicitly taken into account. As a result of this first step the stabilization problem of the neutral equation is reduced to a problem involving only a finite number of characteristic roots. As a second step, stabilization is achieved by shifting the rightmost or unstable characteristic roots to the left half plane in a quasi-continuous way, by applying small changes to the controller parameters, and meanwhile monitoring other characteristic roots with a large real part. A numerical example is presented.     

QFT与神经网络并行控制研究

阐述了定量反馈理论(Quantitative Feedback Theory,简称QFT)的基本原理及设计步骤,并给出了设计实例。在QFT的基础上,提出了一种QFT和神经网络并行控制的方案,以QFT为主控制器,神经网络进行动态误差补偿。QFT控制能克服对象的参数不确定性,保障系统的鲁棒性;神经网络可以进一步提高系统的跟踪精度。仿真表明,这种方法实现了QFT控制和神经网络控制的完美结合,很适合高精度伺服系统的鲁棒控制。     

Computation of QFT bounds for robust tracking specifications

An algorithm is proposed for generation of QFT controller bounds to achieve robust tracking specifications. The proposed algorithm uses quadratic constraints and interval plant templates to compute the bounds, and presents several improvements over existing QFT tracking bound generation algorithms. The proposed algorithm (1) guarantees robustness against template inaccuracies, (2) guarantees robustness against phase discretization, (3) provides a posteriori error estimates, (4) is computationally efficient, achieving a reduction in flops and execution time, typically by 1-2 orders of magnitude. The algorithm is demonstrated on an aircraft example having five uncertain parameters.     

基于多环QFT的飞行仿真转台鲁棒控制

阐述了定量反馈理论(QFT)的基本原理及设计方法,并给出了某型飞行仿真转台的QFT控制器设计实例。为了有效地抑制高频测量噪声对系统的干扰,以及避免系统的高频不确定性,在单环QFT控制的基础上,引入了基于多环QFT的鲁棒控制。理论分析和仿真实验表明,这种多环QFT控制可以明显地缩减控制器的带宽,使系统具有很强的抗高频测量噪声的性能,达到了理想的控制效果。该方法在转台的控制上取得了成功的应用,具有广泛的应用价值。     

A goodness of fit test for copulas based on Rosenblatt's transformation

A goodness of fit test for copulas based on Rosenblatt's transformation is investigated. This test performs well if the marginal distribution functions are known and are used in the test statistic. If the marginal distribution functions are unknown and are replaced by their empirical estimates, then the test's properties change significantly. This is shown in detail by simulation for special cases. A bootstrap version of the test is suggested and it is shown by simulation that it performs well. An empirical application of this test to daily returns of German assets reveals that a Gaussian copula is unsuitable to describe their dependence structure. A t_ν-copula with low degrees of freedom such as ν=4 or 5 fits the data in some cases.     

基于匹配模板的术语自动翻译方法

本文针对于专利术语的特点,建立了一个基于属于模板的术语自动翻译系统。系统中结合了翻译模型和相似度打分机制,实验结果表明该方法能够解决术语翻译中的固定术语翻译问题和基于中心词序调整问题,提高了统计机器防疫的质量。同时术语模板中引用了单一的统计翻译中增加了语言学知识,为翻译提供了一个有效手段。     

Global stabilisation for a class of nonlinear time-delay systems based on dynamical output feedback sliding mode control

In this article, global stabilisation for a class of nonlinear time-varying delay systems with mismatched uncertainty is considered. The bound on the uncertainty is nonlinear and involves time-delay. For this system, a dynamical compensator is first designed. A delay free sliding surface in the augmented space formed by the system output and the compensator state variables is proposed. The stability of the sliding mode dynamics, which include the time-delay effects, are analysed using the Lyapunov–Razumikhin approach. Then, a delay dependent sliding mode control is proposed such that the system can be driven to the sliding surface in finite time and maintain a sliding motion on it thereafter. Finally, a simulation is presented to illustrate the effectiveness of the obtained results.     

基于MSC的TTCN-3测试例生成研究

提出了从消息序列图(MSC)生成TTCN-3测试例的方法.测试者可以先针对被测系统(SUT)中感兴趣的部分利用MSC描述出具体的测试场景,再从MSC映射成TTCN-3测试例.将MSC映射成TTCN.3的方法主要包括对MSC文档、基本MSC和高级MSC这3部分的映射.     

基于MSP430的多功能工业阀门控制系统测试仪

将控制理论应用于工业阀门控制系统(IVCS)的测试中,提出了IVCS较为完善的测试方法。介绍了多功能工业阀门控制系统测试仪(MFTS)的测试原理,给出了MFTS的功能需求及以MSP430单片机为核心的实现方案。     

基于OFGA的软件测试用例自动生成

为提高测试用例生成的质量和效率,提出一种基于最优家族遗传算法(OFGA)的软件测试用例自动生成新算法。基于OFGA的测试用例生成算法在执行过程中适当缩小搜索区域,从而在相对更小的区域内快速寻找最优解。因此,OFGA能比较快地加速算法的收敛,提高算法的效率,在测试用例的生成上具有较大的应用潜力。由实验结果可知,新算法比遗传算法(GA)在测试用例自动生成上耗时更少,效果更佳。     

基于模板距离分布的烟支中心点搜索策略

基于采用模板匹配的方法实现烟支识别与计数的思想,研究识别前烟支中心点搜索策略的一种优化方法.首先依据烟支图像的特点,分析烟支模板中心点的距离分布;在此基础上通过在烟支图像中粗粒度标志出可能的烟支边界,考察非边界点到距其最近边界间的距离,将其与模板距离分布相结合,得到烟支图像中像素点的6种距离分布;按照6种距离分布划分各像素点作为烟支中心点的可能性大小及识别优先级;最后按照识别优先级由大至小依次搜索烟支中心点.实验表明,该方法对孤立烟支的中心点定位和连通烟支的中心点定位同样有效,与全局遍历法相比,能提高烟支识别与计数的精确性.     

基于扩展有限状态机测试序列生成方法研究

扩展有限状态机是对有限状态机的扩展,由于引入了变量、状态迁移的前置条件以及状态迁移所引起的操作,它的测试序列存在可执行性问题。讨论了基于扩展有限状态机的测试序列生成方法的主要特点及局限性,指出了有待进一步研究的若干问题。     

A small-gain condition for iISS of interconnected retarded systems based on Lyapunov-Krasovskii functionals

This paper considers interconnected retarded nonlinear systems. Integral input-to-state stable subsystems and the construction of Lyapunov-Krasovskii functionals for their interconnections are focused on. Both discrete and distributed time-delays in the subsystems and the communication channels are covered. This paper provides a sufficient small-gain type condition for the stability of the interconnected systems with respect to external inputs in the framework of Lyapunov-Krasovskii functionals. Global asymptotic stability is addressed as a special case which deals with time-varying delays in communication channels effectively.     

基于最小割集的安全性测试用例的动态生成

利用故障树的原理和方法,对基于故障树最小割集的安全性测试用例动态生成进行了研究.首先阐述了故障树和故障树最小割集的概念及数学描述,然后给出了故障树最小割集的生成算法,最后在此基础上提出了基于故障树最小割集的动态生成安全性测试用例的算法.     

基于相似粗糙集的气象范例库的生成方法

基于范例推理的气象灾害预测领域,从气象数据库中提取出典型的源范例是首要的步骤,而获取高质量且无噪声干扰的气象范例,减少范例存储的时间和空间复杂度是其主要目标.提出了利用相似粗糙集进行气象范例提取的算法,通过简化相似天气的无向图,自动从原始天气数据中提取典型范例.该算法能较好的处理噪声的干扰,并能直接处理连续数值型属性,避免了复杂的属性离散化的计算.实验结果验证了算法的可行性和有效性.     

基于UML协作图的测试用例生成方法与实现

根据组件软件的特征,提出一种基于UML协作图直接产生测试用例的方法.给出了一系列覆盖准则,并针对协作图中条件、并发和循环消息流提出相应的处理方法.采用深度优先的算法遍历所有测试场景,每个测试场景相应于一个测试用例,并设计和实现了测试用例自动生成工具系统UMLTCG.     

基于蚁群算法的软件测试数据自动生成

提出了一种基于蚁群算法的测试数据自动生成方法。该方法采用位串形式编码,实现了被测程序输入空间到蚂蚁路径网络的映射模型。根据程序插装函数定义的路径信息素轨迹强度,蚂蚁进行群体协作搜索最佳路径,生成测试数据。在基本蚁群算法基础上,通过引入变异算子和自适应挥发系数,提高了蚂蚁路径的多样性,克服了早熟停滞的缺陷。和模拟退火遗传算法进行了对比实验研究,结果表明了该方法的可行性,生成测试数据的效率优于模拟退火遗传算法。     

基于场景技术的嵌入式软件测试用例生成方法

软件测试自动化是当前软件测试的发展趋势.场景技术的引入可以更有效地进行测试用例的描述,从而有助于实现软件测试自动化,提高测试效率和测试的可维护性、可重复性.从被测系统的文档分析入手,将场景技术运用于测试用例生成过程中,提出了嵌入式软件测试用例生成方法,并将该方法运用到实际的软件测试中,验证了该方法的正确性和有效性.