考虑非理想排错过程的软件可靠性模型

经典的可靠性模型排错过程是理想的,没有考虑各种实际情况.实际的排错过程并不是完美的,错误排除需要时间,且不可能完全排除,排错过程中可能引入新的错误,错误排除率和错误引入率均是随时间变化的函数等等.文中针对这些排错过程的实际情况,对Xuemei Zhang等人提出的软件可靠性模型进行了改进,提出新的假设,建立改进的新模型,给出模型的一般表达形式.并通过两组公开发表的失效数据,对改进后模型的一个特例模型的拟合预测能力进行仿真分析比较,最终验证了改进的考虑非理想排错过程的软件可靠性模型的优越性,说明了新模型更符合现实的软件可靠性活动过程.     

一个考虑多种排错延迟的NHPP类软件可靠性增长模型

软件可靠性增长模型通常假设软件的测试环境与软件实际运行的现场环境相同,期望利用测试阶段获得的失效数据评估软件在现场运行时的失效行为。多数非齐次泊松过程类软件可靠性增长模型假设软件故障被发现后立即被排除,这点假设无论是在测试环境还是在现场环境下都很难实现。根据故障对测试过程的影响,故障的排错时间可被分为多种。提出了一个考虑多种排错延迟的软件可靠性增长模型,讨论了基于这个模型的故障排除效率函数,指出从用户角度出发讨论软件可靠性时必须考虑重复性故障。     

考虑测试工作量和故障检测率的软件可靠性模型

针对软件可靠性模型中对故障检测率行为描述的不足,考虑软件固有的故障检测率是一个随时间增加的减函数,以及测试人员的学习能力是一个随时间增加呈S型的增函数,两者共同决定了故障检测率是一个随时间增加的先增后减的函数,于是提出改进的软件可靠性模型。在改进模型的基础上,考虑测试工作量对可靠性的影响,软件可靠性模型得到了进一步的改善。利用公开发表的失效数据集对改进的模型进行比较和验证,实验数据证明改进的模型具有很好的效果。     

考虑系统调用和失效模式的软件可靠性模型

可靠性是软件系统质量需求中的一个重要指标,而软件可靠性建模为人们提供了一种评估软件可靠性的方法,能够在软件质量控制方面有效地提供决策依据。无论是曾经受到广泛关注的黑盒方法,还是现在大量研究的白盒方法,这些模型都试图越来越精确地刻画软件的可靠性。然而,这些模型都是将软件独立在运行环境之外,只是纯粹地、抽象地考虑软件本身,完全忽略了软件所依赖的操作系统和运行环境对可靠性的影响。将软件运行所依赖的系统调用纳入了考虑范畴,考虑了软件中的多种失效模式（内核态失效、用户态失效）,同时对系统中的错误传播行为进行了建模,经过对经典模型逐步扩展,建立了一个更加符合实际情况的软件可靠性模型。通过一个实例详细描述了该模型的如何应用。     

故障检测率不规则变化的软件可靠性模型

传统的NHPP(non-homogeneous Poisson process)模型在实际的测试当中被证明是成功的.但是,由于传统的NHPP模型用的是理想的假设,例如,假设故障检测率是常数、平稳变化和规律变化,模型的性能在实际的测试环境中总是受到损害.因此,提出一个基于NHPP的软件可靠增长模型,并且考虑故障检测率的不规则变化情况,这种变化符合故障检测率在实际的软件测试过程中的变化.通过相关的实验验证了所提出的NHPP模型的拟合和预测能力.实验结果表明:在用实际的故障数据进行拟合和预测的过程中,所提出的模型与传统的NHPP模型相比,有更好的拟合和预测性能.同时,也给出了所提出模型相应的置信区间.     

考虑排错过程引进故障的开源软件可靠性模型研究

近年来,开源软件在软件行业很受欢迎。但是,开源软件的可靠性却受到人们的广泛质疑。如何评估开源软件的可靠性是一个重要的问题。与传统的闭源软件相比,在建立开源软件可靠性模型时,必须考虑故障引入和故障检测与排错之间的延迟时间这两个因素。本文考虑了排错过程和不完美调试现象,提出了相应的开源软件可靠性模型。并且我们用两个开源软件故障数据集实来验证提出模型的拟合性能与预测性能。实验结果表明,提出的模型在开源软件可靠性评估中具有良好的拟合和预测性能。提出的模型可以用于开源软件在实际的开发过程中的可靠性评估。     

一种考虑软件补丁的软件可靠性模型研究

将调整因子引入到关于软件产品的可靠性预计模型中,提出了改进的关于软件产品的软件可靠性预计模型.通过一组数据仿真证明,改进模型比原模型有着更好的性能,更加符合现实的软件可靠性活动过程.     

考虑测试与运行差别的软件可靠性增长模型

软件可靠性增长模型中测试阶段和操作运行阶段环境的不同导致了两个阶段故障检测率的不同．在随机过程类非齐次泊松过程（NHPP）中的经典模型G—O模型基础上,考虑运行剖面和测试剖面的不同,对测试阶段和操作运行阶段的故障检测率进行了转化,得到了较好的刻画测试阶段和操作阶段失效率差别的模型（TO—SRGM）．最后,通过实例用最小二乘法对此模型的参数进行了估计．实验结果表明,在某些失效数据集上TO—SRGM的拟和效果比G—O模型和PZ—SRGM好．     

考虑故障相关的软件可靠性增长模型研究

软件可靠性增长模型是用来评估和预测软件可靠性的重要工具.目前,绝大多数的软件可靠性增长模型并没有考虑故障之间的相关性,也没有考虑测试环境和运行环境的区别.文中提出了一种随机过程类非齐次泊松过程(NHPP)中的考虑故障相关性、测试环境和运行环境差别的模型.在两组失效数据上的实验分析表明:对这两组失效数据,文中提出的模型比其他一些非齐次泊松过程类模型的拟合效果和预测效果更好.     

考虑不完美排错情况的NHPP 类软件可靠性增长模型

针对现有NHPP 类软件可靠性增长模型对故障排错过程中不完美排错情况考虑不完全的现状,提出了一 种新的软件可靠性增长模型.该模型全面考虑了不完美排错的两种情况:既考虑了排错过程中引入新错误的可能性, 又考虑了不完全排错的情况,并且引入了一种故障排除率随时间变化的故障排除率函数,使模型更符合实际情况.利 用公开发表的两组不同的软件失效数据对该模型进行验证的结果表明,与现有的对不完美排错情况考虑不完全的 模型相比,该模型能够取得更好的拟合结果和预测效果.     

A hybrid model for spelling error detection and correction for Urdu language

Neural Computing and Applications - Detecting and correcting misspelled words in a written text are of great importance in many natural language processing applications. Errors can be broadly...     

Stereo error detection, correction, and evaluation

An algorithm is presented for error detection and correction of disparity, as a process separate from stereo matching, with the contention that matching is not necessarily the best way to utilize all the physical constraints characteristic to stereopsis. As a result of the bias in stereo research towards matching, vision tasks like surface interpolation and object modeling have to accept erroneous data from the stereo matchers without the benefits of any intervening stage of error correction. An algorithm which identifies all errors in disparity data that can be detected on the basis of figural continuity and corrects them is presented. The algorithm can be used as a postprocessor to any edged-based stereo matching algorithm, and can additionally be used to automatically provide quantitative evaluations on the performance of matching algorithms of this class     

Optimal schedule and effort considering the penalty cost of schedule delay in software development

This study presents an optimization model that considers the penalty cost due to the contract-schedule delay, when trading off between scheduling and effort in software development project. The optimal combination between the schedule and the effort is shown to depend on the penalty cost. This study also addresses analysis for the effects of software size misestimation and penalty cost change. A simple example is given to illustrate the results of our study.     

The effect of imperfect error detection on reliability assessmentvia life testing

Measurement of software reliability by life testing involves executing the software on large numbers of test cases and recording the results. The number of failures observed is used to bound the failure probability even if the number of failures observed is zero. Typical analyses assume that all failures that occur are observed, but, in practice, failures occur without being observed. In this paper, we examine the effect of imperfect error detection, i.e. the situation in which a failure of the software may not be observed. If a conventional analysis associated with life testing is used, the confidence in the bound on the failure probability is optimistic. Our results show that imperfect error detection does not necessarily limit the ability of life testing to bound the probability of failure to the very low values required in critical systems. However, we show that the confidence level associated with a bound on failure probability cannot necessarily be made as high as desired, unless very strong assumptions are made about the error detection mechanism. Such assumptions are unlikely to be met in practice, and so life testing is likely to be useful only for situations in which very high confidence levels are not required     

网络结构的软件系统可靠性分配方法

针对网络结构的软件系统,通过构造软件系统的ANP结构,结合用户和程序员的观点,对超矩阵的构造进行了改进,提出基于改进型ANP的模块重要度评估方法。以软件实用性最大化为目标函数、以可靠性下限和开发费用为约束条件,建立了可靠性分配模型。并以某工厂实力信息管理系统为例,对算法进行了验证。     

一种软件可靠性测试模型研究

在马尔可夫链模型的基础上,将测试问题转化为一个数学问题。通过建立软件的使用链,根据使用链进行序列抽样,产生测试用例,将软件测试结果的分析问题转化为一个经典概率问题。运用实例证明,这种技术具有一定的实用性和有效性。     

软件可靠性增长G-O模型的改进

在传统的软件可靠性增长G-O模型中,故障检测率和初始的故障总数是影响软件可靠性的2个重要因素.为了提高软件可靠性评估的可信性,考虑到在软件纠错的过程中可能会引入新的错误,把模型中潜在的故障总数和故障检测率看作随时间变化的函数,提出了改进的G-O模型,给出了解析方法,并将改进前后的G-O模型进行了对比,通过实例进行了验证...     

An extended domain-based model of software reliability

A definition of software reliability is proposed in which reliability is treated as a generalization of the probability of correctness of the software in question. A tolerance function is introduced as a method of characterizing an acceptable level of correctness. This in turn is used, together with the probability function defining the operational input distribution, as a parameter of the definition of reliability. It is shown that the definition can be used to provide many natural models of reliability by varying the tolerance function and that it may be reasonably approximated using well-chosen test sets. It is also shown that there is an inherent limitation to the measurement of reliability using finite test sets     

Scene adaptive structured light using error detection and correction

In this paper, we present a new structured light 3D reconstruction method that can be applied to scenes in the presence of global illumination such as inter-reflection, subsurface scattering and severe projector defocus. The proposed method takes advantage of important properties embedded in the binary code patterns, and determines the minimum stripe width that eliminates the effects of subsurface scattering and projector defocus in the capturing stage. Moreover, errors caused by inter-reflection are detected, and corrected by an iterative approach. Our method can be applied to scenes where more than one global illumination effect appears in a scene point. The accuracy of our method is demonstrated by quantitative evaluation, and its robustness by qualitative evaluation when applying to real-world scenes with various characteristics, both of which are better than two of the currently known best methods.