Detectability in stochastic discrete event systems

A discrete event system possesses the property of detectability if it allows an observer to perfectly estimate the current state of the system after a finite number of observed symbols, i.e., detectability captures the ability of an observer to eventually perfectly estimate the system state. In this paper we analyze detectability in stochastic discrete event systems (SDES) that can be modeled as probabilistic finite automata. More specifically, we define the notion of A-detectability, which characterizes our ability to estimate the current state of a given SDES with increasing certainty as we observe more output symbols. The notion of A-detectability is differentiated from previous notions for detectability in SDES because it takes into account the probability of problematic observation sequences (that do not allow us to perfectly deduce the system state), whereas previous notions for detectability in SDES considered each observation sequence that can be generated by the underlying system. We discuss observer-based techniques that can be used to verify A-detectability, and provide associated necessary and sufficient conditions. We also prove that A-detectability is a PSPACE-hard problem.     

像面位置可调定焦距标星电视系统结构设计

为了标定试验设备空间位置,研制了一种像面位置可调的定焦距标星电视系统.星光经主镜和次镜反射后通过透镜组聚焦,成像在CCD靶面上;采用直线位移平台改变CCD靶面沿光轴方向的位置,直线位移误差不大于0.002 mm,解决了由于温度变形使星像偏离CCD靶面产生成像不清晰的问题.通过可见光探测标星试验验证,定焦距标星电视系统的...     

舰载红外系统对反舰导弹探测能力的计算模型

通过分析反舰导弹的红外辐射特征,给出了不同气象条件和传输路径上红外大气传输的衰减方程,然后给出舰载红外系统对反舰导弹红外探测能力的计算模型.在模型的求导过程中,考虑了光机扫描型和凝视型两种红外系统的不同,结合影响探测能力的多种因素,进一步完善了光机扫描型和凝视型红外系统的作用距离方程和目标发现概率计算模型,可对不同气象...     

非线性哈密顿控制系统输出反馈同时镇定(英文)

研究有限多个非线性哈密顿控制系统同时镇定问题,给出了若干输出反馈同时镇定控制器设计新结果.首先,利用哈密顿系统的结构特性和零状态可检测性,得到了一种新的设计方法.然后,研究哈密顿系统中含有外部干扰和结构不确定性的情形,设计了三种同时镇定控制器：一个是鲁棒同时镇定器,一个是自适应同时镇定器,最后一个是鲁棒自适应H∞同时镇定器.例子和仿真研究表明：本文提出的控制器设计方法是行之有效的.     

月基望远镜探测能力的地面标定

采用模拟试验在地面测试了月基望远镜(LOT)的星等探测信噪比及弥散斑能量集中度,用以验证望远镜的探测能力.与传统的通过分析CCD各项参数对噪声的影响来获得信噪比的方法不同,本文提出的方法客观、直接地通过图像信息来计算星点目标信噪比,其目标信噪比测试不确定度可优于8％.在测试弥散斑能量集中度时,通过质心算法求其弥散斑能量中心,进而提出了一种星点弥散斑高斯拟合方法来拟合弥散斑能量分布曲线.这种高斯拟合方法可使弥散斑能量集中度的测试精度提高10％.最后,通过试验测试了LOT相机星等探测信噪比及弥散斑能量集中度,验证了LOT相机+15 Mv的探测能力.     

Uniform Global Asymptotic Stability of Differential Inclusions

Stability of differential inclusions defined by locally Lipschitz compact valued mappings is considered. It is shown that if such a differential inclusion is globally asymptotically stable, then, in fact, it is uniformly globally asymptotically stable (with respect to initial states in compacts). This statement is trivial for differential equations, but here we provide the extension to compact- (not necessarily convex-) valued differential inclusions. The main result is presented in a context which is useful for control-theoretic applications: a differential inclusion with two outputs is considered, and the result applies to the property of global error detectability.     

Observing the state with componentwise exponentially decaying error

The componentwise exponential asymptotically stable (CWEAS) observer is defined. Its estimation error is componentwise and absolutely bounded by prespecified decaying exponentials. Using the notion of CWEAS introduced earlier, an existence condition for such an observer is proved. Via eigenvalues location and convexity of certain functions one states the maximization problem of the damping factor of the above exponentials and introduces and characterizes the CWEAS detectability. This is an explicit property of the observability pair (A, C), which, under a certain condition involving the pair (B, D), suffices for strong^* detectability and therefore for the existence of a strong observer.     

Probabilistic fault grading based on activation checking and observability analysis

A simplified probabilistic fault grading method is described. The concept of propagation probability is introduced in place of the sensitization probability of STAFAN, and the empirical parameters of STAFAN are eliminated. The division of input vectors into subsets is monitored by the activation or toggle rate. The accuracy of the method is examined for fault coverage estimation and for predicting the undetected faults.     

信号检测对二分群体决策的模拟

用信号检测系统模拟二分群体决策问题，在４个假设条件下，定义了测试者的检测能力指数，从而计算群体决策绩效。用二元信号检测的最大后验概率最大似然准则作为个体决策者的判决依据。     

Target detectability as a function of target speed, noise level, and location.

An experiment was conducted using a PPI radar display on which 40 Ss observed targets displayed in each of 4 contiguous 30-degree scope sectors at each of 4 radial velocities under 2 levels of visual noise. Analysis of variance of the mixed Latin-square design did not reveal reliable differences in scores due to velocity, noise level, or velocity orders. More target designations occurred for the inner than the outer contiguous scope sectors (p = .001), although the ratios of correct to total calls per sector were not different (p > .05). These results were interpreted as being due to differences in scan frequency rather than reinforcement frequency. From Psyc Abstracts 36:05:5LK26B. (PsycINFO Database Record (c) 2010 APA, all rights reserved)