CSR: SMALL: Robust Algorithms for an Open Source Software Reliability Tool

所有软件成功的关键在于其可靠性。该项目将开发一个开源软件可靠性工具，使软件工程师能够自动应用软件可靠性模型，以帮助组织确保他们开发的软件应用程序可以无故障运行。传统的算法在数值上是不稳定的，这意味着如果初始估计不准确，它们可能会失败。算法的失败使得不可能应用软件可靠性模型来做出有用的预测，例如软件应用程序应该被测试以达到期望的可靠性水平的额外时间量。这项研究的目标是开发数值稳定的算法，即使初始估计不准确也会成功。期望最大化（EM）和期望条件最大化（ECM）算法将被开发的故障率和非齐次泊松过程（NHPP）的软件可靠性模型。传统的EM算法施加限制性的假设，限制其应用程序，只有最简单的模型，而ECM算法的潜力还没有得到充分的探讨。因此，这项研究的挑战将消除现有的EM算法的限制和设计有效的ECM算法的软件可靠性模型。这些数值稳定的EM和ECM算法的实现将被纳入开源工具，以确保软件可靠性模型可以成功应用。算法的增强稳定性和工具的开源性质可以促进定量软件可靠性模型的广泛使用，使公司和组织能够缩短软件产品的上市时间或现场。

The key to the success of all software is its reliability. This project will develop an open source software reliability tool that will allow software engineers to automatically apply software reliability models to help organizations ensure that software applications they develop can operate free of failures. Traditional algorithms are numerically unstable, meaning that they can fail if initial estimates are inaccurate. Failure of an algorithm renders it impossible to apply a software reliability model to make useful predictions such as the amount of additional time a software application should be tested in order to achieve a desired level of reliability. The goal of this research is to develop numerically stable algorithms that will succeed even if the initial estimates are inaccurate. Expectation maximization (EM) and expectation conditional maximization (ECM) algorithms will be developed for failure rate and nonhomogeneous Poisson process (NHPP) software reliability models. Traditional EM algorithms impose restrictive assumptions that limit their application to only the simplest models, while the potential of the ECM algorithm has not been fully explored. Therefore, this research challenge will remove the restrictions of existing EM algorithms and design efficient ECM algorithms for software reliability models. Implementations of these numerically stable EM and ECM algorithms will be incorporated into the open source tool to ensure that software reliability models can be applied successfully. The enhanced stability of the algorithms and the open source nature of the tool may promote widespread use of quantitative software reliability models, enabling companies and organizations to improve time to market or field a software product.