【摘要】 UML是软件工程中广泛应用的建模语言 ,但其主要问题是缺少严格的形式化语义 ,因而描述的模型容易产生歧义 根据UML活动图的语法和工作流系统的特点 ,为UML活动图定义了一种执行语义 基于时间转变系统模型 ,将工作流系统的执行描述为时间转变和数据转变两个交替进行的过程 时间转变描述时间的前进 ,数据转变修改工作流案例的状态 ,这种语义比层次状态图具有更强的描述并行的能力 ,比Petri网和进程代数更适合描述工作流模型更多还原

【Abstract】 UML is a widely used modeling language in software engineering, but its main problem is the ambiguity because UML has no formal semantics. A formal execution semantic of UML activity diagram is presented for modeling workflow systems according to the syntax of UML activity diagram and the characteristic of the workflow system. The semantic is based on the clock transition system model. The execution of workflow system is formalized as two processes, clock transition and data transition, executing by turns. Time goes forward in clock transition, and the state of the workflow case transforms in data transition. The semantics is more expressive in concurrency than the semantics based on statechart, more adaptable to the workflow system then Petri-net or process algebra.更多还原