顺序迭代开发过程建模与仿真

Modeling and simulating of sequential iterative development processes

为有效地管理和改进产品开发过程,提出了一种基于奖赏马尔科夫链的顺序迭代过程定量模型。该模型与已有的顺序迭代过程模型不同的是,模型中的返工影响因子不仅作用于直接返工任务的持续时间,而且作用于该返工任务的后续任务,即作用于返工任务的整个剩余时间。一个任务在每个阶段的返工量随着迭代次数的增加而逐渐减少。考虑了不同任务引起的同一任务返工量的不同。为估计开发过程的期望时间,建立了过程时间估计的分析模型和仿真模型,给出了仿真计算算法。以软件测试过程为例,给出了过程时间估计的分析和仿真实验结果,并与其他已有模型进行了对比分析。最后,讨论了模型估计结果产生偏差的可能原因。

To effectively manage and improve the product development processes, a reward-Markov-chain-based quantitative model was proposed for sequential iterative processes. This model was different from existing sequential iterative process models in several aspects. The influencing factors for rework in the model not only influenced the duration of the rework task, but also influenced the durations of the tasks following the rework task, i.e. it influneced the remaining time of the rework task. The rework amount of a task decreased as the increase of iteration times at each stage. The model differentiated the task rework amount caused by different tasks. To estimate the expectant development cycle, an analysis model and a simulation model were established for sequential iterative process estimation, and a simulation algorithm was also presented. The process time estimation models were illustrated by a software testing process. Analysis and comparisons between the proposed models and other existing models were presented according to the experiment results. Finally, the possible causes for deviation from the practical process time of estimated result were discussed.