【作者】 王伟；

【导师】 王海洋；

【作者基本信息】 山东大学 ， 计算机软件与理论， 2005， 硕士

【摘要】 工作流技术是实现企业业务过程建模、仿真优化分析、过程管理与集成,最终实现业务过程自动化的核心技术。越来越多的企业引入了工作流技术以支持其商务活动。 工作流技术的研究十分活跃,人们从工作流模型、体系结构、事务、适应性、异常、安全、语言、形式化、正确性验证、资源管理、开发过程等各方面对工作流技术进行探讨,并开发出很多原型系统。市场上也出现了很多具有实用价值的工作流产品。 尽管工作流技术取得了进步,但理论基础的研究还很不够。现有的工作流管理系统从功能、可靠性、健壮性上与数据库管理系统无法相提并论。有很多因素限制了工作流的发展,使得工作流达不到实用性的标准,不能大规模的投入应用。这些因素包括底层模型不完备、系统对异常的处理策略不完善、系统的安全性不能很好的保证等。 由于技术的不断进步、需求和规则的不断变化、新方法的引进,商务过程模型也不断的被检查、改善和调整以适应不断变换的环境。当模型修改时,工作流的某些实例可能还在运行,如何使得工作流正确的执行,这是工作流动态修改要研究的问题。这时可以有如下策略:1) 允许所有的实例按照旧的模型执行,新实例则遵从新的模型;但是新的实例必须等待所有正在运行实例执行完成后才能开始执行;2) 中断所有正在运行的实例,所有实例按照新的模型重新执行;但是这样做会给企业带来很大的损失,有些损失是不可接受的;3) 改变正在执行的实例,通过执行一系列补偿或撤销操作,使实例按照新的模型执行。很多动态修改的算更多还原

【Abstract】 The workflow technology is a crucial technology to realize modeling of business process、 analyzing of emulations process management and aggregation and ultimately to achieve the goal of automation of business process. More and more enterprises adapt WFMS as a platform to support their business process.The research of workflow is animated. People probe the technology in many aspects, such as workflow model、 architecture、 transaction、 compatibility、 exception、 safety、 language、 verification of soundness、 management of resources、 the process of developing and so on. They also develop meta-model systems to support and check up their theories. There are also many workflow products commercially available in market.Thorough there are rapid progress in workflow research, the theoretical basis of workflow is far from enough. The existing Workflow Management Systems are not comparable with Database Management Systems in functions reliability and soundness. Many factors restrain the development of workflow, which now could not satisfy the utilitarian standard and therefore could not be put to use on a large scale. The factors are various, for example, the foundational model is unsound、 the exception handlingstrategy is not integrated and the security of the system is not conformed.Due to the continually accelerating pace of technological advancements, changing requirements and regulations, and introduction of new methods, business process models are being constantly reviewed, improved and adapted to the changing environment. When workflow model changes, some of the workflow instances may still be running. Normally, there are three methods: 1) all current instances are allowed to complete according to the old process model, but new instances are planned to follow new model. New instances may be put on hold, until all current instances have completed. 2) Active workflow instances may be aborted when process model is changed, all instances follow the new model all over again; This approach may incur losses to the organization. In some cases, the losses may be unacceptable. 3) We can bring the instances in compliance with the new specification by undoing or compensating some of the completed tasks. Many dynamic modification algorithms take the third way.Workflow exception handling is a pivot issue which ensure a more reliable process when process execution is wrong. It is necessary to combine the transaction feature of workflow process, Because workflow process has the feature of transaction and it’s execution control structure is familiar with advanced transaction model. Researchers present the concept of transaction workflows and advanced workflow model. We will adapt the concept of execution property of tasks to realize more reliable dynamic modification of workflows.One of the major factors restraining the wider applicability and acceptability of workflows is that workflow technology to date does not provide sufficient support for modification of ongoing workflows. The existing modification methodologies have provided comprehensive frameworks to support Dynamic Workflows, but few has paied attention to the exception handling of the Modification process. Exception duringthe modification process would leave the workflow in an inconsistent state or even bring undesirable results in some cases. In this paper, we do the following work:1) giving the definition of task execution property;2) defining a new workflow model, including process execution model3) present a solution for implementing more reliable dynamic modification by adding exception handling in this process.更多还原