基于目标部分满意度的需求设计方案评估

Evaluation of Requirement and Design Approach Based on Partial Goal Satisfaction

不同的需求设计方案对软件系统中非功能目标的实现具有不同的影响。这些非功能目标一般不能以一种绝对清晰定义的程度来满足,常常是以一种部分满意的方式实现,现实中寻求"满意"解比寻求"最优"解更符合实际情况。为了反映此特性,该文在分析目前已存在方法局限性的基础上,利用Letier和Lamsweedre提出的基于概率理论的面向目标的推理方法,对目标部分满意度建模。模型建立在客观标准基础上,在领域内具有实际物理解释,获得了不同方案对目标满意度的影响,可更好地用于指导需求分析和设计决策。

Difterent approach contributes to different degrees of achievement of non-functional goals. As it often happens, non-functional goals do not need to be satisfied in an absolute sense. Most analysis techniques consider absolute goal satisfaction only, they do not support the evaluation of generated alternatives to guide the selection of most appropriate ones. Letier and van Lamsweerde presented a model technique for specifying partial degrees of goal satisfaction and for quantifying the impact of different system alternatives on high-level goals that may be satisfied only partially. Within such model, non-functional goals are specified in a precise, probabilistic way; their specification is interpreted in terms of application-specific measures： Thus, it may be used to guide requirements elaboration and design decision making.