Abstract: Time element as an important part of the work flow management, is a key factor affecting the implementation business process. Since tasks have the characteristic of a time limit in workflow, this paper analyzes time element of tasks, abstract formal description of tasks, quantify maximum time constraint of two consecutive tasks in execution process, proposes controllable time constraint Petri net（Time Constraint-Net, TC-Net） model. In order to improve description precision task time in the model, time information is added to tasks, from start execution time to end execution time, and maximum time constraint. It uses TC-Net model to represent tasks in workflow. Based on the order of between tasks, synchronization, and parallel transfer model relationship, it can refine actual business process analysis granularity. It applies one instance on TC-Net model for analysis model. The results show that the method is highly sensitive on irregularities caused by violation time, solves a single task irregularities and process cycle unreasonable problems, achieves the management and monitoring of business processes.

Key words: workflow, Petri net, time constraint, illegal operation

摘要： 时间要素作为工作流管理的重要部分，是影响企业业务流程部署实施的关键因素。基于工作流中任务具有时间限制的特点，分析任务的时间要素，抽象出任务的形式化描述，定量计算两个连续任务执行的最大时间约束，提出可控时间约束Petri网模型（Time Constraint-Net，TC-Net）。该模型在任务节点中添加时间信息，从任务开始执行时间到任务的执行结束时间及最大约束时间，提高任务时间信息描述精度;利用TC-Net模型表示工作流过程中各项任务，基于任务间顺序、同步和并行关系的传递模型，细化实际业务流程中分析粒度。应用TC-Net模型进行实例分析，实验结果表明该工作流建模方法对时间违反而导致违规操作具有高敏感性，解决了单个任务违规和流程周期不合理两类问题，实现业务过程的管理和监控。

关键词: 工作流, Petri网, 时间约束, 违规操作