扩展的模糊时间Petri网

网络实时系统对时间和QoS有严格要求.扩展的模糊时间Petri网是一种对网络实时系统进行建模和分析的形式化模型,Petri网数学理论基础能保证并发系统的可靠性和正确性.本文介绍了扩展的模糊时间Petri网的定义,模型检验方法,仿真工具,网精简技术和应用领域,并探讨了进一步研究的方向.     

基于UML-OOPN的武器装备体系可靠性建模方法

针对传统可靠性模型在武器装备体系建模中存在的描述能力不足和Petri网建模存在的模型爆炸和模型构建困难问题,引入面向对象建模思想,利用UML模型便于描述系统和对象Petri网模型易于动态仿真的优点,提出了基于UML-OOPN的武器装备体系任务可靠性建模方法,通过建立UML到对象Petri网的映射规则,完成了由任务描述模型向任务可靠性对象Petri网模型的转化,从而实现了两者有效结合,并以某野战防空反导体系为例验证了该方法的可行性和有效性,为解决武器装备体系任务可靠性模型构建和高效输入问题提供了一种新的方法.     

MapReduce的随机Petri网模型研究

首次提出用随机Petri网为MapReduce逻辑模型建立Petri网模型的思想,目的在于采用随机Petri网工作流性质对其进行分析。因此,在研究MapReduce逻辑模型的基础上,为其建立了随机Petri网模型。该随机Petri网模型符合随机Petri网工作流系统的性质,本文利用随机Petri网的工作流系统的性能等价公式,分析了模型的性能,最终求出整个系统的性能参数。该性能参数能够很好地说明MapReduce处理大数据集的优势。     

基于微分Petri网的业务流程模块适配方法

为适应业务流程多功能及动态变化的需求，用模块替换的方法对业务流程建模是解决问题的快速有效途径之一.以开放Petri网与微分Petri网为基础，提出了微分控制Petri网和微分数据Petri网的概念，分别从语义学角度利用微分Petri网的演化表达式对模型的控制流网与数据流网进行活性检测，利用微分Petri网对替换模块及其离散部分与连续部分进行结构稳定性分析，以达到业务流程模块适配分析.理论分析结果表明，所建立的微分表达式能够反映模型活性与稳定性，模块适配效果较好.最后基于平台数据进行仿真分析，实验结果表明本文所提的方法有一定的可行性.     

随机Petri网模型中变迁的串、并联性能等价化简技术

随机Petri网的状态空间爆炸问题的研究始终是Petri网研究的主要问题之一.在随机Petri网模型中,变迁的串、并联是Petri网模型的主要基本形式,对它的化简不仅有助于解决随机Petri网状态空间的爆炸问题,而且也为其他随机Petri网的化简技术提供一个坚实的基础.另外在诸如工作流、多媒体等重要的随机Petri网模型中也存在大量的变迁的串、并联结构,所以对随机Petri网模型变迁的串、并联的化简,特别是能够推导出它的性能等价的数学公式就显得很有必要.本文详细阐述了随机Petri网变迁的串并联的模型化简技术,推导出了变迁的串、并联化简的性能等价公式,并给出一个化简的例子,最后对结果的相关问题进行了分析.     

AADL模型到广义随机Petri网的转换工具

为了便于对体系结构设计和分析语言AADL可靠性模型进行可靠性评估,实现AADL模型到广义随机Petri网模型(GSPN)可靠性计算模型的自动转换,依据AADL模型到GSPN模型的转换规则,设计并实现了集成在开源工具OSATE上的模型转换工具。实验表明:该文的转换工具可以将AADL可靠性模型自动转换为GSPN模型。     

SPN在网络安全保密系统可靠性分析中的应用

文章针对网络安全保密系统的安全需求和运行特性,引入Petri网理论指导网络安全保密系统的可靠性建模与分析过程。首先详细描述了运用随机Petri网对网络安全保密系统进行可靠性建模与分析的具体方法和过程;然后给出一个实例,对系统的保密性服务子系统进行建模,并分析了该子系统在安全运行状态下的可靠性。通过对可靠性建模分析方法的应用,不仅实现了系统方案设计阶段可靠性的可评估性,而且提高了系统后期开发过程的可操作性。     

基于Petri网和Web服务的工作流建模方案

面向Web服务的工作流系统能很好地满足现代企业应用集成和协作的需求，Web服务流程模型的建立是实现Web服务集成的重要环节。Petri网具有形式化的描述的基础和正确性分析的优点。文章将这两方面结合起来．对工作流网中控制流结构进行了分析，给出了由Petri网向WSFL转化的方法，并给出Petri模型中控制流结构的WSFL描述。     

一种随机Petri网性能等价化简与分析方法

随机Petri网模型是系统性能评价的有力工具,但其状态空间随模型规模的增长而指数性增长的问题限制了其对复杂和大规模系统模型的性能数量分析能力.因此,在对模型进行分析之前,先对其进行适当的性能等价化简,是一种更为可行的分析方法.本文首先讨论了一类随机Petri网-基本随机Petri网(ESPN)的性能等价分析方法,这类随机Petri网由顺序、并行、选择和循环等四种基本结构及其组合构成.作者推导出这四种基本结构的性能等价公式,并运用自底向上逐步综合替代的分层分析方法,给出这类随机Petri网模型的性能等价化简分析方法,该方法的复杂性随模型增长而线性增长,有效解决了其性能数量分析问题.然后,讨论了两种非基本结构到基本结构的转换规则,使得复杂的随机Petri网模型也可能转换为ESPN模型,从而使性能等价算法可应用于一般随机Petri网.     

应用Petri网进行业务处理流程模型设计

针对网络业务管理系统中业务处理流程设计描述的复杂化，提出应用Petri网来进行模型设计，并应用关联矩阵进行系统状态分析，表现出动态、异步系统建模分析上Petri网理论的有效性。     

测量系统的量值特性与可靠性

通过对测量系统的量值特性指标与可靠性指标的分析，指出了目前对测量系统的量值分析与可靠性分析完全脱离的现状。在此基础上，分析了测量系统量值特性及其随时间的变化规律，阐述了目前测量系统可靠性指标的评价及其存在的问题。基于前面的分析及测量系统进行量值传递的特点，对测量系统的可靠性重新进行了定义，提出了采用动态不确定度对测量系统的可靠度、校准或检定周期进行评价的新方法，从而结束了目前测量系统量值分析与可靠性分析脱离的现状。     

一种基于模拟退火的协同优化可靠性分析方法

为了在多学科系统中深入研究可靠性分析方法,同时考虑到不确定性因素的影响,将模拟退火算法与可靠性分析相结合,提出一种新的基于模拟退火的协同优化可靠性分析方法。详细介绍了该方法的模型、数学表达式及算法流程,并以实际算例加以验证。算例结果表明该方法用来进行多学科环境下的可靠性分析时,比蒙特卡罗法更加计算准确,并且降低了计算成本。     

Software reliability analysis based on a nonhomogeneous error detection rate model

A software reliability growth model discussed here assumes a nonhomogeneous error detection rate per error which characterizes a software reliability growth process during the testing phase. The methods for software reliability assessment are reviewed, and the model fitting and software reliability analysis for some software error data sets are presented. The optimum software release times are also given for the data analysis results.     

电子线路可靠性容差分析方法及其应用的研究

电子线路是电子系统的组成部分，其可靠性对整个电子系统的可靠性具有很大影响。本文介绍了两种电子线路可靠性容差分析方法（区间分析法和仿射分析法）的基本原理，采用区间分析法和仿射分析法对模拟二阶带通滤波器进行了可靠性容差分析，仿真和实验结果表明：区间分析法和仿射分析法在二阶带通滤波器可靠性容差分析中的应用是有效的；仿射分析法的估计区间比区间分析法的估计区间更接近实际区间，即仿射分析法优于区间分析法。     

Reliability of systems by mixture forms of uncertainty

In this paper we focus on reliability analysis of systems whose components can be described in both a probability context and a possibility context. We introduce a uniform representation of reliability characteristics by different forms of uncertainty. The time-dependent reliability analysis of one-unit systems is presented. The various properties and methods for computing the reliability of coherent systems are studied. For illustrating the results obtained, series and parallel systems are considered and a numerical example is proposed.     

Software reliability measurement

The measurement and analysis aspects of software reliability are described with the aim of providing software engineers and managers a sense of where and how software reliability measurements can be applied to their projects. Some background for understanding software reliability measurement is provided, and activities associated with measuring and analyzing software reliability are discussed in the context of the software product life cycle. The focus is on failures and the rate at which they occur. The thrust of reliability measurement and analysis is to specify what the customer needs in terms of reliability before a software product is built, to validate that these needs are met before delivery of the product to the customer, and to make sure that the customer's needs continue to be met after delivery     

Using statistically designed experiments to improve reliability andto achieve robust reliability

This tutorial explains statistically designed experiments which provide a proactive means to improve reliability as advocated by Genichi Taguchi. That is, by systematic experimentation, the important parameters (factors) affecting reliability can be identified along with parameter values that yield reliability gains. In addition to improving reliability, Taguchi's robust design can be used to achieve robust reliability; that is, to make a process or product reliability insensitive to factors which are hard or impossible to control. Robust design is also implemented using statistically designed experiments. This paper presents classes of experimental plans for reliability improvement and robust reliability. An important feature of the reliability data collected from such experiments is censoring which occurs when some of the experimental units have not failed by the end of the experiment. Consequently, the analysis methodology must account for these censored data which are likely to occur in light of the ever increasing reliability of today's products. Several appropriate methods are discussed briefly. These experimental plans and analysis methods are illustrated using three documented experiments which improved fluorescent lamp and industrial thermostat reliability and which achieved robust reliability for night-vision goggles     

Dynamic reliability analysis of coherent multistate systems

This paper generalizes 2-state (binary-state) reliability parameters `R(t), F(t), λ(t), and mean-time to-failure' to multi-state reliability parameters `R(t,i), G(t,i), λ(t,i), mean-life-span-at-specified-performance-level(i), for each state'. By using these generalized reliability parameters, multi-state reliability dynamic analysis can be transformed to a set of 2-state reliability dynamic analyses. Then, the authors extend some theoretical results in 2-state reliability analysis to the multi-state case. Measures for evaluating performance degradation of multi-state system are developed. By combining Markov processes and s-coherent multi-state system structure functions, the dynamic multi-state reliability can be analyzed. Several examples are given     

方案阶段的可靠性设计

从可靠性需求、可靠性预计分析、可靠性方案设计等方面论述了方案阶段可靠性设计工作应注重的几个问题,并提出一些实用的设计方法,以期对装备方案研制阶段的总体设计提供参考.     

Noise as a diagnostic and prediction tool in reliability physics

A review of the possibility of using noise measurements in analysis and prediction of electron device reliability is given. The noise as an informative parameter for device reliability and its advantages and disadvantages are discussed. A review of qualitative and quantitative noise reliability indicators for diodes, transistors and integrated circuits as well as the methods for failure and defect analysis are presented.