An agent modeling approach

In the proposed definition, the concept of agent is central but, depending on the background of each reader, this word can be replaced by sub-system, object, actor, etc.

A composite system is now referred as a group of agents interacting together for reaching a goal assigned to the group. Three major roles of an agent are:

1. Internal state. An agent is characterized by its `internal state'; by analogy with human agents, this internal state is sometimes called 'mental state'. It contains beliefs and knowledge of the agent, about its own goals and plans, about the external world, and about the internal state of other agents. This internal state will evolve with time, depending on the agent's perceptions and actions.
2. Cooperation. To contribute to the solving of goals attached to a composite system, usually, an agent will not act autonomously but will require cooperation with other agents. Examples of cooperation include `delegation', `commitments', `authorizations', etc.
3. Communication. In order to cooperate effectively, an agent must have knowledge about the other agents. Thereby, it must be able to communicate with other agents in the system (i.e. send and receive messages to and from other agents).