The Application of Object-Oriented Analysis to Agent-Based Systems

Agents are important software abstractions for distributed problem solving and autonomous, proactive behavior. They have been used in many applications, including manufacturing, enterprise integration, network management, and advanced user interfaces for worldwide web applications. As agent systems become more prevalent, the need arises for software engineering methodologies. The relationships between agents and objects, and the role of object oriented analysis in multiagent system development are discussed here. The approach is illustrated with a case study from discrete parts manufacturing. 1.0 INTRODUCTION Numerous examples can be found of applications of agent based systems to enterprise integration; concurrent engineering; and manufacturing. Many agent based systems have also been developed for network management, scheduling, and advanced user interfaces. These systems exhibit significant advances in distributed problem solving and pro-active behavior. For many areas, especially humancomputerinteraction (HCI), worldwideweb applications, and business process management, agents that pro-actively carry out autonomous behavior and cooperate with each other through negotiation represent the next important software abstraction or metaphor. As agent oriented systems become more widely used and integrated to mainstream applications, software engineering becomes an important consideration. To date, most agent based systems have been developed within the artificial intelligence community, and the need for development methodologies has become well known. Some initial work in software engineering of agent based systems has been completed, but most of it has concentrated on software architecture and omitted specification entirely 18, . Previous work 15 indicated that an agent could be identified as a process or a data store in a data flow diagram with real time extensions. However, agent behavior is actually quite different from a data flow process. The need to consider work flow and not just data flow 23 for agents has been discussed, as agents cooperate and coordinate their activities much as individuals do in organizations or enterprises. As agents must be designed and implemented in software, a workflow representation alone can not be used. In this paper, existing methodologies for object oriented modelling and analysis are extended to encompass agent oriented systems. In particular, the use case driven object oriented software engineering (OOSE) approach is utilized, with extensions for constraint technologies. The result is a methodology for specifying and analysing agent based systems.