Research On Adaptive Workflow Modeling And Dynamic Execution Based On Service Template

Workflow Management System can help enterprises improve efficiency, in addition to make use of resources optimally and reasonable. However, most Workflow Management Systems take static structures, whose adaptive mechanisms in dealing with exceptional conditions are not maturity. In order to dynamically handle conditions as change of workflow structure or content and increase flexibility of business, the construction of adaptive workflow model with processing capacity of emergency has become an important issue in workflow technology field currently. The adaptability of Workflow Management System requires its operation or response automatically with various situations in running process, that is, the system can detect and fix the errors automatically in case of exceptions without manual intervention, in addition to functions of predicting and avoiding similar exceptions. This system, which can help solve problems of lacking flexibility for enterprises, is the development direction of Workflow Management System.In order to solve the problem of hardly dealing with modification of the changes of the enterprise organizational processes using existing workflow management systems, a dynamic workflow modeling architecture is proposed based on service template technology, as well as the business flow definition and service binding. The dynamic and adaptive workflow model established in the form of service template mainly focus on self-adaptive in both establishing and running stages, that is, the stage in which the workflow model dynamically selects and binds services with its activity node, along with the stage in which the workflow model dynamically discovers and handles the service exceptions in running process. The specific content of the paper includes:Firstly, this research constructs adaptive workflow model with the technology of service template. The framework of the workflow model contains several modules such as workflow template operations, service binding, interface, exchange patterns of workflow and so on. Workflow template operating module includes a series of operations of service template creation, selection, modification and deletion. Service binding module includes the discovery, match and replacement of each service in the situation of service changing. All these operations with workflow templates and services binding processes with activity nodes are running on the workflow engine.Secondly, with the method of semantic matching, this research achieves dynamically services selection and load of activity nodes. Each organization unit in adaptive workflow need to package its business processes packaged into corresponding services. These services should be called by Workflow Management System to complete each part of process. The invocation requests from activity nodes to electronic services should be completed through the semantic approach. Besides, through the comprehensive consideration with multiple factors such as data processing efficiency, cost and so on in the knowledge database, the best matching service can be found according to a series of rules defined.Finally, this research proposed a service updating strategy and algorithm, which achieves adaptive update mechanism response to service exceptions in workflow running process. Adaptive Workflow Management System should make judgment on conditions of service exceptions, which mainly based on two aspects, the time that data stays in an organization unit of the workflow is more than expected and the output data the activity exports Report exceptions. In the workflow running stages, when a service binding to one activity node has changed because of original service exception, the entire operations in this workflow needs to be updated automatically, that is, the activity nodes that have not produced instances should re-match services. In the mean time, the dynamic update of rule database should also be taking into account, including recording ability statistics of Load capacity and fault tolerance which can do great help to improve existing processes.An Adaptive Workflow Management System based on service template is designed and accomplished with the method of service exception detection, dynamic selection and adaptive modification in this paper, containing a specific workflow changing instance caused by service exceptions to verify the adaptive updating mechanism. The results show that the adaptive workflow model proposed in this paper can effectively implement recovery and update operations of Workflow Management System under service exceptional conditions, which can ensure the flexible of dynamical change of enterprise business flows.