Workflow System, Task Scheduling Strategy

Workflow technology, since its appearance, is under the close attention of scholars. Scholars pay their attention on the research of workflow model, workflow scheduling algorithm, implementation of workflow systems and get good result.Workflow scheduling have two important aspects, one is instances scheduling. Another is allocation of resources. Workflow instances which belong to the same business process, called the same type instance. Otherwise called different type instance. This paper will discuss scheduling of same type instance. The basic idea is:through the workflow modeling, business process will be transformed into a series of related activities. Each activity is abstracted to the task class in the process of task scheduling, each task can be implemented by a class of resources. When there are many workflow instances need to be implemented in workflow system, through the workflow instance scheduling, the aim of scheduling of tasks can be achieved, allocation of resources also achieved.Specific research work focused on the following areas:1) Workflow process modeling and resource arrangements. Workflow process model is a business process definition that can be understood by computer. The process model includes definition of business activities, constraints of activities and Constraint information of other models. Using colored petri net workflow modeling technology, can clearly describe the complex business processes, and detail relationship of business processes. Resources can execute a class of tasks.Different from task, the state of resources is stable. In this paper we use XML Document to organize resources. XML Documents can describe the organizational relationship between resources, the characteristics of the resource itself, also can add resources information without disrupting the original structure.2) Research on workflow task scheduling strategy. In this paper, through depth study of TSP-PSO, the operation of the algorithm has been improved. And based on the improved algorithm, a particle swarm optimization algorithm for the workflow task scheduling has been proposed. Example analysis shows that the algorithm is efficient.3) The research of scheduling methods in this paper to is simulated.