Comparative performance evaluation of applying extended PIE technique to accelerate software testability analysis

The rapid development of technology provides high performance and reliability for the hardware system; based on this, software engineers can focus their developed software on more convenience and ultra-high reliability. To reach this goal, the testing stage of software development life cycle usually takes more time and effort due to the growing complexity of the software. How to build software that can be tested efficiently has become an important topic in addition to enhancing and developing new testing methods. Thus, research on software testability has been conducted and various methods have been developed. In the past, a dynamic technique for estimating program testability was proposed and called propagation, infection and execution (PIE) analysis. Previous research studies have shown that PIE analysis can complement software testing. However, this method requires a lot of computational overhead in estimating the testability of software components. In this article, we propose an extended PIE (EPIE) method to accelerate the conventional PIE analysis, based on generating group testability as a substitute for statement testability. Our proposed method can be systematically separated into three steps: breaking a program into blocks, dividing the blocks into groups and marking target statements. Experiments and evaluations with the Siemens suite, together with cost-effectiveness analysis, clearly show that the number of analysed statements can be effectively decreased, and the calculated values of testability are still acceptable.     

Applying simulation and design of experiments to the embedded software testing process

This paper presents some original solutions with regard to the deployment of the U.S. Department of Defense Simulation, Test and Evaluation Process (DoD STEP), using an automated target tracking radar system as a case study. Besides the integration of modelling and simulation, to form a model‐based approach to the software testing process, the number of experiments, i.e. test cases, have been dramatically reduced by applying an optimized design‐of‐experiment plan and an orthogonal array‐based robust testing methodology. Also, computer‐based simulation at various abstraction levels of the system/software under test can serve as a test oracle. Simulation‐based (stochastic) experiments, combined with optimized design‐of‐experiment plans, in the case study have shown a minimum productivity increase of 100 times in comparison to current practice without DoD STEP deployment. Copyright © 2004 John Wiley & Sons, Ltd.     

An analysis technique to increase testability of object‐oriented components

Object‐oriented component engineering is increasingly used for system development, partly because it emphasizes portability and reusability. Each time a component is used, it must be retested in the new environment. Unfortunately, the data abstraction that components usually use results in low testability. First, internal variables cannot be directly set. Second, even though a test input may trigger a fault, the failure does not propagate to the output. This paper presents a technique to increase object‐oriented component testability, thereby making it easier to detect faults. Components are often sealed so that source code is not available. The program analysis is performed at the Java component bytecode level. A component's bytecode is analysed to create a control and data flow graph, which is then used to increase component testability by increasing both controllability and observability. We have implemented this technique and applied it to several components. Experimental results reveal that fault detection can be increased by using our increasing testability process. Copyright © 2008 John Wiley & Sons, Ltd.     

不完美排错软件可靠性增长模型效用量化研究

为了进一步提升现有非齐次泊松过程类软件可靠性增长模型的拟合和预测性能,首先从故障总数增长趋势角度对不完美排错模型进行深入研究,提出两个一般性不完美排错框架模型,分别考虑了总故障数量函数与累计检测故障函数间的线性关系与微分关系,并求得累计检测的故障数量与软件中总故障数量函数表达式;其次,在六组真实的失效数据集上对比了提出的两种一般性不完美排错模型和六种不完美排错模型拟合预测性能表现。实例验证结果表明,提出的一般性不完美排错框架模型在大多数失效数据集上都具有优秀的拟合和预测性能,证明了新建模型的有效性和实用性;通过对提出的模型与其他不完美排错模型在数据集上的性能的深入分析,为实际应用中不完美排错模型的选择提出了建议。     

Applying software reliability models to a large industrial dataset

There are more reliability models in literature than experience reports of their application in industry. This paper tries to fill a bit of the hole, reporting the experience matured in Italtel SIT, a major Italian telecommunications company. The paper deals with the following subjects: goals of the experience; overview of the product under examination and its testing process; the method followed for conducting the experience; data analysis strategy; selection of the best models; analysis of their predictive capability; linking of phases by means of compression factors; and tools used to support the work.     

基于偶然性正确测试用例发现的错误定位方法

软件错误定位是目前软件工程领域的重要研究课题,其中基于程序谱的错误定位（CFL）是一类重要的方法。偶然性正确测试用例对于CFL有着很大的负面影响,因此如何发现该类测试用例或者避免它们对CFL的影响对于提高CFL方法的定位效果有着重要的意义。通过分析偶然性正确对CFL定位方法的影响,发现一种没有误判率（false positive）的寻找偶然性正确测试用例的方法。在此基础上,提出了一种基于偶然性正确测试用例发现的CFL定位方法。通过实验表明,该方法可以普遍改善已有CFL方法的定位效果。     

Assessing the risk due to software faults: estimates of failure rate versus evidence of perfection

In the debate over the assessment of software reliability (or safety), as applied to critical software, two extreme positions can be discerned: the ‘statistical’ position, which requires that the claims of reliability be supported by statistical inference from realistic testing or operation, and the ‘perfectionist’ position, which requires convincing indications that the software is free from defects. These two positions naturally lead to requiring different kinds of supporting evidence, and actually to stating the dependability requirements in different ways, not allowing any direct comparison. There is often confusion about the relationship between statements about software failure rates and about software correctness, and about which evidence can support either kind of statement. This note clarifies the meaning of the two kinds of statement and how they relate to the probability of failure-free operation, and discusses their practical merits, especially for high required reliability or safety. © 1998 John Wiley & Sons, Ltd.     

An empirical evaluation of six methods to detect faults in software

Although numerous empirical studies have been conducted to measure the fault detection capability of software analysis methods, few studies have been conducted using programs of similar size and characteristics. Therefore, it is difficult to derive meaningful conclusions on the relative detection ability and cost‐effectiveness of various fault detection methods. In order to compare fault detection capability objectively, experiments must be conducted using the same set of programs to evaluate all methods and must involve participants who possess comparable levels of technical expertise. One such experiment was ‘Conflict1’, which compared voting, a testing method, self‐checks, code reading by stepwise refinement and data‐flow analysis methods on eight versions of a battle simulation program. Since an inspection method was not included in the comparison, the authors conducted a follow‐up experiment ‘Conflict2’, in which five of the eight versions from Conflict1 were subjected to Fagan inspection. Conflict2 examined not only the number and types of faults detected by each method, but also the cost‐effectiveness of each method, by comparing the average amount of effort expended in detecting faults. The primary findings of the Conflict2 experiment are the following. First, voting detected the largest number of faults, followed by the testing method, Fagan inspection, self‐checks, code reading and data‐flow analysis. Second, the voting, testing and inspection methods were largely complementary to each other in the types of faults detected. Third, inspection was far more cost‐effective than the testing method studied. Copyright © 2002 John Wiley & Sons, Ltd.     

失效上下文统计分析的软件故障定位方法

针对程序切片方法不提供语句的可疑程度描述,而覆盖分析方法不能充分分析程序元素间的相互影响等问题,提出上下文统计分析的软件故障定位方法。首先,将源程序转换为抽象语法树和程序依赖图;接下来,插桩程序,收集运行时信息;然后,根据失效点,执行按需的反向动态切片,确定失效产生的上下文;最后,对于反向动态切片中的节点,统计计算可疑度,输出带可疑度排序的动态程序切片。该方法不但描述了失效产生的上下文,还计算上下文中各个语句的可疑度。实验结果表明,所提方法与单一的覆盖分析方法相比,平均Expense降低了1.3%,与单一的切片方法相比,平均Expense降低了5.6%,所提方法可以有效辅助开发人员定位与修正软件缺陷。     

基于仿真技术的调节阀选型教学软件的设计

以调节阀选型的教学为目的,深入研究了多种调节阀的结构特点及其输入输出特性,对调节阀的选型步骤和选型方法进行了软件实现,并对其动态特性进行了仿真分析。在Visual Studio2008环境中使用C++编程,实现了调节阀的选型、流量系数的计算、输入输出特性的仿真分析及故障情况下流出特性的仿真分析等功能。     

拟贝叶斯推断算法在软件可靠性模型中的应用

本文针对工程软件的可靠性评估,提出了一种基于不精确概率的拟贝叶斯软件可靠性统计推断算法,以区间值概率替代传统贝叶斯可靠性模型中精确概率先验,能更准确地表达专家的模糊信息并避免做出与实际不符的假设。在开目PDM某组件中的应用实践表明,该算法能在小样本的测试数据下快速地逼近模型参数的准确值。     

拓扑指数计算软件的开发与设计

用MATLAB语言开发设计拓扑指数计算软件,软件包括8个菜单,即分子结构文件载入、拓扑指数计算、数据载人、数据预处理、统计分析、系统菜单、帮助菜单和退出系统。不仅能计算多类重要的拓扑指数,还能统计分析和预报计算结果。具有操作简便、界面友好、功能完善等特点。软件适合从事化学信息学、QSAR/QSPR的工作者使用。     

A formal approach to perfective software maintenance: System integration using a basis of formal object-oriented components

We investigate how a formalism known as a basis and common to many areas of applied mathematics and engineering can be applied to perfective maintenance and the integration of application systems in software engineering, using an object-oriented approach. It is concluded that this formalism serves as a mathematical model for perfective software maintenance and software systems integration activities under object-oriented development. Theorems and properties about the model are reported as guides to software maintenance. The model and formal maintenance techniques have been applied to a software system in the management information systems area to demonstrate this approach to perfective maintenance and to assist in validating the model.     

一种适用于具有相互依赖基本事件和重复事件的动态故障树独立模块识别方法

为减小时间开销,动态故障树经常被模块化分解为独立的静态子树和独立的动态子树,然后分别使用二叉决策图和马尔卡夫模型求解;其中的一个关键问题便是识别具有相互依赖基本事件和重复事件的动态故障树中所有的独立模块和最小独立模块.文中提出了一个基于亲戚依赖关系的独立模块识别方法IIMKDR,该方法将故障树按照其事件之间的依赖关系转换为依赖树;基于面向对象思想,为依赖树及其节点构建对象;通过对各节点对象属性的分析,得出独立模块集并进而求出最小独立模块集.最后对IIMKDR方法进行了理论分析和实验验证,分析表明该方法适用于具有相互依赖基本事件和重复事件的动态故障树独立模块识别.与其它方法从多个角度所进行的实验对比显示,当故障树没有相互依赖基本事件和重复事件时,该方法的开销略高于其它方法;当故障树具有相互依赖基本事件和重复事件时,该方法能够正确识别其中所有的独立模块,而其它方法不具备这样的功能.     

Applying an improved failure mode effect analysis method to evaluate the safety of a three‐in‐one machine tool

Straighteners are commonly used in the field of plate straightening. With the shortage of industrial land, an increasing number of straightener manufacturers integrate uncoilers, straighteners, and feeders, which represent a three‐in‐one machine tool. The tool's functions are complex; many factors affect its reliability and performance, including the problems of equipment itself and human errors. To improve the reliability of this machine, it is necessary to identify the main failure modes and causes. The risk assessment of using the conventional failure mode and effects analysis (FMEA) presents several issues. Thus, multiple methods have been proposed to improve the robustness and applicability of the FMEA. Herein, an improved FMEA, which combines fuzzy set and entropy evaluations is utilized to assess the three‐in‐one machine tool. In the method, the fuzzy set method is used to quantify the evaluation index. The information entropy and expert evaluation method are used to determine the weight between the indexes. From this study, human operation errors accounted for over 55% of the risks of machine malfunctions. By evaluating failure modes, a few countermeasures to reduce human operation errors can be proposed. By improving the human machine interface design and ergonomic job design and providing adequate training, human errors can be reduced and the reliability of three‐in‐one machine tools can be improved.