Most practical applications have dynamic attributes, but conventional access control mechanisms have not addressed the problem sufficiently. In this paper, we discuss how to realize an access control system that enables us to manage dynamic security policies. Our proposed method is based on Role-Based Access Control (RBAC), and the agent decides access rights dynamically for the abstract role, which is defined by the role administrator statically using context-enabled rules and an inference engine. By defining rules using declarative representation (logic programming style), bidirectional queries can be realized for USER-ROLE-PERMISSION relationships. In this paper, we will demonstrate the usefulness of our proposed system by presenting our project management application and its access control system.