Service Agent-Modeling And Plan Scheduling System

Agent is a rapidly developing and widely used technology for the recent years, an agent is an entity featured by its autonomy, collaboration and intelligence. By using Agent technology, the deficiencies of web service, for example, the functions is too simple, can't act to the external environment, can be solved, and the Agent technology can combine, manage, select and optimize services, so to provide with better service quality.Based on BDI Agent Theory, and by using JADE as the platform of Agent executing engine, this paper articulates and implements an agent modeling framework, plan selection and trigger strategy as well as the event mechanism. The architect of an agent includes belief set, plan library and behaviors. The belief set is the knowledge that an agent learned, that is what an agent knows to the external environment; Plans represent the agents'means to act to the service request; one behavior is a single service, several behaviors constitute a plan by certain logical order.In order to make the services an agent provides better fit to the users'requirements, we divide the belief set into world model and constrain model. World model is the status and information collection that the agent have now, and the constrain model represent the users'certain requirements to the agent. By adding constrains to the attributes of plans, we make agents act according to what the users want.As the core of the agent execution, plans are the module that an agent act to the outside and the schedule strategy is a mechanism to filter, select and trigger plans, and make the plans better serves the users. In this process, we take the advantage of Drools, a rule engine, to separate the plan library and rule library, and helps generating loosely-coupled application system. The whole plan schedule system is done by taking the 3-step method: firstly the system parses the content carried by the event and matches the templates between the event and plans; Secondly, by initiating the rule engine, and take the constrains inside constrain model as the rules; Then the last step is to execute a priority based selection algorithm to select the best plan that fit to the current requirements during those candidate plans and decide if the plan is to be executed immediately or add to the waiting queue according to the status of the event wait queue. Meanwhile, the paper designed time, message, internal event and belief trigger, and encapsulate these into a uniformed event system, making the plans event driven. This modeling and plan scheduling system make the agent more flexible, stronger and better serves the users.