Service-PlugIn mechanism for distributed application system

We assume that an application system may be constructed from: scenario, role, and function. In our proposed architecture (Y. Sakashita et al., 1999), the business flow is defined by scenario, which is constructed from activities based on role. Each role has a mission whose aim is to sub-goal with an approach of its own. It needs to accomplish the sub-goal so that the system gets suitable execution functions over the network environments. We also propose a function implementation mechanism based on Plug-In.