关于软件可靠性测试的若干问题

软件可靠性测试是软件测试的一种形式,它强调软件测试与软件可靠性之间的定量关系,旨在定量改进和评估软件可靠性。从数学角度严格量化软件测试与软件可靠性之间的关系是一件困难的事情。本文举例说明软件可靠性测试中的几个问题,包括软件缺陷的估计、软件测试过程的数学建模、以及软件可靠度的最优估计等。由此可知,软件可靠性测试涉及到不同领域的知识和多种数学工具。     

软件测试数据的统计分析

软件可靠性评估是软件可靠性研究的重要问题,本文研究了软件测试数据的样本点序法,获得了软件可靠度的置信下限,证明了该置信限的最优性。最后给出一个实例说明该方法的可行性。     

Designing a software reliability programme

Designing reliable software is becoming an ever increasing problem because the high cost of software is largely due to reliability problems. The costs of finding and fixing the errors, better known as maintenance and testing costs, account for as much as 80 per cent of the total cost of the final software product. Software developers now have an even greater interest in preventing errors from making their way into the software and finding the errors that are present in the early stages of development. Precise software design, coding and testing play an important role. This paper presents a management plan for implementing a software reliability programme at a small software industry where no reliability programme yet exists and no reliability programme is yet established.     

Economic analysis of software release problems with warranty cost and reliability requirement

We discuss optimal software release problems which consider both a present value and a warranty period (in the operational phase) during which the developer has to pay the cost for fixing any faults detected. It is very important with respect to software development management that we solve an optimal software testing time by integrating the total expected testing cost and the reliability requirement. We apply a nonhomogeneous Poisson process model to the formulation of a software cost model and analyze three typical cases of the cost model. Moreover, we derive several optimal release polices. Finally, numerical examples are shown to illustrate the results of the optimal policies.     

加强软件质量控制,提高军用软件的可靠性水平

针对军用软件在质量和可靠性方面存在的问题,提出了提高军用软件质量和可靠性的措施和方法。     

某测试软件输入模块的可靠性测试方法研究

采用黑盒测试方法对某数据采集系统的测试软件进行了测试.通过对软件需求和性能的分析,建立了软件的运行剖面和测试案例,进行了可靠性测试,得到了该软件输入模块的可靠性测试结果.     

高可靠性软件的极值统计分析

提出了极值统计分析的方法．对于失效数据极值分布函数的拟合检验，采用了相关系数法；对于母体分布的参数估计，则分别采用了最小二乘估计（LSE）和极大似然估计（MLE）；最后通过一个实例说明了统计过程，并用模拟的方法证明了最小二乘估计较好。     

Reliability-based maintenance and job scheduling for identical parallel machines

Quality has an important role in manufacturing, and on the other hand, machine condition has a significant effect on quality. Based on this fact, all manufacturers integrate the production scheduling with maintenance activities to keep the machines in perfect conditions. In this paper, we propose a mixed integer nonlinear model to optimise the quality cost, maintenance cost, earliness–tardiness cost and interruption cost simultaneously. We assume that if machines work in undesirable conditions, their quality is reduced, resulting in quality cost. On the other hand, if the machines are repaired to decrease the quality cost, maintenance cost and other cost such as earliness–tardiness cost and interruption cost are imposed to the manufacturer. Several numerical instances are implemented by the proposed model to show the model effectiveness to obtain the best maintenance and production scheduling with minimum quality cost.     

一类柔性机器人装配系统的优化调度

研究了印刷电路板柔性机器人装配系统的中的优化调度问题,该系统中的机器人都具有一定的柔性,因而某些装配操作可由不同的机器人来完成,且所需装配时间也可以不同。本文针对这类机器人装配系统,采用一种新算法,以解决此类系统的优化调度问题,并通过算例验证了该逄法的有效性。     

Optimal scheduling for sequentially connected cluster tools with dual-armed robots and a single input and output module

We examine a cyclic scheduling problem of sequentially connected cluster tools with a single input and output module, which includes multi-cluster tools and linear cluster tools. Every component tool has a dual-armed robot, and chambers are parallelised for a long process step. An intermediate buffer between each pair of adjacent component tools has a limited capacity, and all processed wafers should return to the input and output module. To examine the scheduling problem, we first compute workloads of the process steps and robots to obtain a lower bound on the tool cycle time. We then identify a rule of assigning the chambers to the process steps that makes the tool cycle time independent of the order of using the parallel chambers. We also propose a simple robot task sequence which is modified from the well-known swap sequence for each component tool. We prove that the modified swap sequence is optimal when one of the process steps, not a robot, is the bottleneck. We also present a scheduling strategy which controls robot task timings to deal with interference of wafer flows between each pair of adjacent component tools. Finally, we perform numerical experiments to show the performance of the proposed sequence.     

A study of operational and testing reliability in software reliability analysis

Software reliability is an important aspect of any complex equipment today. Software reliability is usually estimated based on reliability models such as nonhomogeneous Poisson process (NHPP) models. Software systems are improving in testing phase, while it normally does not change in operational phase. Depending on whether the reliability is to be predicted for testing phase or operation phase, different measure should be used. In this paper, two different reliability concepts, namely, the operational reliability and the testing reliability, are clarified and studied in detail. These concepts have been mixed up or even misused in some existing literature. Using different reliability concept will lead to different reliability values obtained and it will further lead to different reliability-based decisions made. The difference of the estimated reliabilities is studied and the effect on the optimal release time is investigated.