软件自适应的建模和形式化验证是提高自适应软件开发效率、保证自适应软件可靠性的基础,现有研究中软件自适应可视化建模与形式化建模相隔离,一定程度上阻碍了自适应软件的开发.为此,提出MV4SAS的方法,将可视化的UML与严格化的时间自动机相结合,用于软件自适应的建模和形式化验证.首先,应用UML扩展机制引入新的构造型、标记值和约束条件,定义软件自适应建模设施,在此基础上构造软件自适应结构模型和行为模型;然后,根据定义好的转换算法将软件自适应行为模型转换为时间自动机网络,建立软件自适应形式化模型;最后,定义一组软件自适应形式化验证性质,并利用模型检测工具UPPAAL验证软件自适应模型的可靠性.案例研究表明,该方法可有效降低软件自适应建模和验证的复杂度,提高软件自适应的建模效率和模型可靠性.
Modeling and formal verification for software self-adaptation are the basis to improve development efficiency and to ensure reliability of self-adaptive software. However, there is a gap between visual modeling and formal modeling of software self-adaptation in existing work, which to some degree hampers the development of self-adaptive software. In order to systematically support modeling and formal verification for self-adaptive software, an approach called MV4 SAS is proposed in this paper by incorporating the visual UML and the strictly defined timed automata. Firstly, the modeling facilities are defined by introducing new stereotypes, tagged values and constraints with UML extending mechanism, and the structural and behavioral models are created on the ground of the newly created facilities. Secondly, the behavioral model of self-adaptive software is mapped to timed automata network according to the predefined transformation algorithm, and the formal model of self-adaptive software is then created. Finally, using the model-checking tool UPPAAL, the reliability of software self-adaptation is verified with a set of predefined properties. Case study shows that the proposed approach can effectively reduce the modeling and verification complexity and improve development efficiency and reliability of self-adaptive software.