中文摘要：

时间管理是工作流管理系统应提供的重要功能,其中一个关键问题是分析时间约束的可行性,并调整时间约束以避免可能出现的违反.然而,在高度不确定的工作流环境下,传统定性的时间约束分析结果过于严格.因此,提出概率时间约束工作流网来描述时间约束下的工作流流程.基于该网提出一种方法,以随机的形式分析活动满足时间约束的概率.该概率能帮助流程管理者灵活地分析时间约束的可行性,进一步为时间约束调整提供精确的指导.此外,用一个实际工作流管理系统中的例子验证工作的有效性.

英文摘要：

Han Rui,Liu Yingbo,Wen Lijie,and Wang Jianmin（School of Software,Tsinghua University,Beijing 100084） （Key Laboratory for Information System Security,Ministry of Education,Beijing 100084）（Tsinghua National Laboratory for Information Science and Technology（TNList）,Beijing 100084） Dealing with time and time constraints is crucial in designing and managing business processes,so time management should be an important part of workflow management systems. One key issue in time management is to analyze the feasibility of time constraints. Besides,when time constraints are violated,they should be adjusted to regain a satisfaction state. Traditional work on time constraint analysis considers discrete activity （execution） durations and presents qualitative analysis result such as time constraints are satisfied or violated. However,the dynamic nature of workflows causes high uncertainties in workflow process,thus activities of workflow process probabilistically satisfy their time constraints,e.g.,95% of activities satisfy their time constraints. Therefore,traditional deterministic analysis is too rigorous. For such an issue,probabilistic time constraint workflow nets （PTCWF-nets） are introduced to describe uncertainties in time-constrained workflow process. Based on PTCWF-nets,a probabilistic approach is proposed at worklow build-time. This approach analyzes every activity＇s probability of satisfying time constraints in a stochastic way. This quantitative analysis result allows process designer to flexibly check the feasibility of time constraints. The result also provides a precise estimation to guide time constraint adjustment. Moreover,the proposed approach is implemented in a real-world workflow management system,and its effectiveness is evaluated by means of a concrete example.