基于有限状态进程的事件约束定义

测试分布式程序需要定义事件约束来检测程序执行产生的事件序列.事件约束需要根据程序的规约来推导.FSP是一类描述并发程序形式化规约的进程代数记法.它将并发进程描述为动作序列,其中动作可对应到规约级事件.E-CSPE约束在给定状态谓词下定义前后运行事件间的顺序关系.根据FSP的操作符和并发控制机制可推导E-CSPE约束.推导出来的E-CSPE约束考虑到并发程序的安全和进展属性,可据以判断程序运行的正确性和测试的充分性.     

基于事件约束的分布式程序正确性测试

由于并发的存在和不确定性,在以规约为基础来测试分布式程序的正确性时,必须考虑程序 执行时的内部状态.这些内部状态通过端口显示为事件序列,程序规约需要对序列中各事件间 的依赖关系作约定,即定义事件约束集.该文提出了E-CSPE(extended-constraints on suc ceeding and preceding events),以形式化描述这类事件约束,它由3个基本描述规则组成, 分别对应于3种不同类型的事件约束.通过判断程序执行时所产生的事件序 列集同这些事件约束集的一致性以及对约束集覆盖程     

E-CSPE约束的一致性判定

分布式程序目前被大量使用．由于并发的存在，测试分布式程序需要采用事件约束来判定运行事件序列的正确性，事件约束之间需要判定一致性．初始的事件约束可以通过规约来定义，作者提出E-CSPE约束的描述规则来推导新约束，并提出约束之间的一致性判定机制．该算法具有多项式复杂度．     

面向Java的分布式程序测试系统

由于程序的分布运行,测试分布式程序必须同时考虑并发特性和运行环境.介绍了一个面向Java语言的分布式程序测试系统JDPT(Java-oriented distributed program testing system).JDPT基于运行环境定义事件,通过事件序列记录分布式程序的运行过程,并定义事件约束检测可行事件序列集的有效性.通过该技术,JDPT可以有效地判断程序在运行环境中并发执行的正确性,适用于跨平台的Java程序测试.     

PMTree:一种高效的事件流模式匹配方法

复杂事件处理技术从多个持续事件流中分析并提取满足特定模式的事件序列.高吞吐率场景下,如何快速准确地识别事件序列是复杂事件处理技术中一个非常重要的问题.现在事件流的模式匹配方法——NFA、Petri网、有向图等——存在语义描述能力不足、部分算子实现代价高等缺陷.针对这一现状,设计并实现了一种基于树的模式匹配方法——PMTree.PMTree定义了事件模型及相应事件算子,将事件序列映射为树节点,同时将时间窗口约束及谓词约束等放置在相应节点,这些树节点连接成一棵PMTree来支持实时的事件筛选与过滤.进一步研究了PMTree构建过程中的优化策略,并提出了开销模型以及优化构建算法,以尽可能减少模式匹配开销.实验结果表明,相同测试条件下基于PMTree实现的复杂事件处理引擎Cesar吞吐率是基于NFA实现的开源引擎Esper的3～6倍,并且在不同事件量或事件序列复杂度下性能表现稳定.     

接口时序一致性连续定量监测技术研究

为了解决电气系统接口时序一致性的长期连续定量监测问题,设计了一种基于对比测试的时序一致性监测系统。该系统通过建立时序参数的描述模型将时序约束统一为约束矢量并通过图形化界面输入,约束矢量包含时序参数的测点及约束条件。将理想时序周期内同一事件下各信号的逻辑值编为事件码并按事件先后顺序排列,以事件码序列为码型触发的模式序列,基于设计的DEW-BM算法捕获与模式序列匹配的目标数据序列并计算其中各时序参数的测量值,通过验证测量值是否满足约束不等式给出接口时序一致性的监测结果(Pass/Fail)。测试结果表明,监测系统能够正确捕获目标信号,时序一致性分析结果与理论期望结果一致,监测系统具有一定的正确性和通用性。     

基于行为树的协议建模方法及其应用研究

为解决现有协议建模方法验证困难及测试序列生成算法复杂度高和测试序列长的问题,提出了一种基于行为树(BT)的协议描述新方法.采用行为树模型对协议的控制流程进行建模,提出了基于行为树描述的协议验证方法,并给出了基于行为树的测试序列生成方法.以某监控协议为例给出了基于行为树的建模过程,将所建模型转换为通信顺序进程(CSP)后采用过程分析工具(PAT)完成了协议验证,并完成了测试序列的计算与对比分析,结果表明提出的方法能方便地完成对协议的描述与验证,能降低测试序列计算复杂度并减少生成的测试序列长度.     

一种基于模式的故障诊断方法

提出一种改进的基于模式的故障诊断方法。将故障定义为可以用正则表达式描述的模式,避免了传统的用 “特殊”事件表示故障的局限性。将正则表达式转化成等价的确定性有限自动机,便于构造故障模式空间。故障模式 空间包含系统所有的故障信息,可以描述单故障、故障序列、多故障、间歇性故障等多种故障形式。最后给出基于故障 模式空间的可诊断性定义和诊断系统。     

基于事件约束的软件过程验证

软件过程是以人为中心的系统,其特点是动态性和不断演化.既定过程模型在实际执行时往往有所偏差.基于E-CSPE(extended constraints on succeeding and proceeding events)约束实现过程验证和偏差测量.事件约束根据过程模型定义.过程实例执行被记录为事件序列.通过分析事件序列对事件约束的覆盖和违反结果,可以计算EPD(event constraint based process difference metric)和EAD(event constraint based activity deviation metric)指标.EPD指标可以反映过程执行与过程模型的偏差,EAD指标则为过程演化提供依据.     

测试非确定性系统的一种结构化方法

本文对非确定性的分布式系统的相容性测试提出一种新的方法，这种方法是经典的状态识别方法的一种扩展。我们提出了集合识别的概念，重新定义了区别序列和ＵＩＯ序列，最后我们给出了层次测试的方法。     

Discovering frequent event patterns with multiple granularities intime sequences

An important usage of time sequences is to discover temporal patterns. The discovery process usually starts with a user specified skeleton, called an event structure, which consists of a number of variables representing events and temporal constraints among these variables; the goal of the discovery is to find temporal patterns, i.e., instantiations of the variables in the structure that appear frequently in the time sequence. The paper introduces event structures that have temporal constraints with multiple granularities, defines the pattern discovery problem with these structures, and studies effective algorithms to solve it. The basic components of the algorithms include timed automata with granularities (TAGs) and a number of heuristics. The TAGs are for testing whether a specific temporal pattern, called a candidate complex event type, appears frequently in a time sequence. Since there are often a huge number of candidate event types for a usual event structure, heuristics are presented aiming at reducing the number of candidate event types and reducing the time spent by the TAGs testing whether a candidate type does appear frequently in the sequence. These heuristics exploit the information provided by explicit and implicit temporal constraints with granularity in the given event structure. The paper also gives the results of an experiment to show the effectiveness of the heuristics on a real data set     

<Emphasis Type="Italic">SetExp</Emphasis>: a method of transformation of timed automata into finite state automata

Real-time discrete event systems are discrete event systems with timing constraints, and can be modeled by timed automata. The latter are convenient for modeling real-time discrete event systems. However, due to their infinite state space, timed automata are not suitable for studying real-time discrete event systems. On the other hand, finite state automata, as the name suggests, are convenient for modeling and studying non-real time discrete event systems. To take into account the advantages of finite state automata, an approach for studying real-time discrete event systems is to transform, by abstraction, the timed automata modeling them into finite state automata which describe the same behaviors. Then, studies are performed on the finite state automata model by adapting methods designed for non real-time discrete event systems. In this paper, we present a method for transforming timed automata into special finite state automata called Set-Exp automata. The method, called SetExp, models the passing of time as real events in two types: Set events which correspond to resets with programming of clocks, and Exp events which correspond to the expiration of clocks. These events allow to express the timing constraints as events order constraints. SetExp limits the state space explosion problem in comparison to other transformation methods of timed automata, notably when the magnitude of the constants used to express the timing constraints are high. Moreover, SetExp is suitable, for example, in supervisory control and conformance testing of real-time discrete event systems.     

Self-tuning gross heat release computation for internal combustion engines

The paper describes a novel method for self-tuning gross heat release computation in internal combustion engines suitable for both online usage in combustion phasing control applications and post-processing of cylinder pressure measurements. The method estimates the polytropic exponents and cylinder pressure offsets immediately preceding and succeeding the combustion event, respectively, using a fast nonlinear least-squares method. The polytropic exponent and the pressure offset are subsequently interpolated during the combustion event and a net heat release computation is performed based on the interpolated exponent and pressure. The result is a self-tuning gross heat release algorithm with no need to model heat losses, crevice losses and blow-by explicitly.     

一个用于Java程序可达性测试的改进方案

Java程序的并发性使它比串行程序更难测试,而可达性测试是一种有效的并发程序测试方法。首先比较了现有的Java程序可达性测试技术,进而提出了一种融合的改进方案以提高同步序列集的生成效率。然后指出新方案已覆盖了用伯恩斯坦条件裁减同步序列集的功能。最后详述如何通过扫描源程序来自动获取同步事件的时序约束关系,进而减少不可行的同步序列,并介绍了相应的实现算法和数据结构。     

Intersecting polyhedra with successive planes

An algorithm that computes the intersections of a set of non-overlapping arbitrary polyhedra with a series of planes is described. Each succeeding plane intersection is computed using information from the preceding intersection. Only changes to the preceding intersection are considered, making testing of the polyhedra minimal. Successions of intersecting planes that are translations of one another and those that are rotations of one another are considered.