This activity aims at defining the complete life-cycle of a role; Roles identified during the IRI activity are here specialized in Agent Roles interacting each others by means of communications. The behavior of Agent Roles is described by a set of Agent Tasks that are the refinement of the Problem Domain Role Tasks and contribute to provide (a portion of) an Agent Role’s service. At this level of abstraction, this kind of task is no more considered atomic but it can be decomposed in finer grained Agent Actions.
An Agent Action is now the atomic unit of a behavior specification. An action
takes a set of inputs and converts them into a set of outputs, though either or both sets may be empty. An example of the most basic Agent Action consists in
invoking a capacity or requesting a service (as explained in following subsections).
The Role Behavior Description is the refinement of the results produced by
the Role Plan activity performed in the System Requirement phase. The behavior
of each role is now described using a state-chart or an activity diagram but the use
of state-charts is preferred because of the intrinsic state-based nature of roles in
our approach. If a role requires capacities or provides services, this activity has to
describe tasks and actions in which they are really used or provided. The designer
describes the dynamical behavior of the role starting from the Role Plan drawn
in the previous phase and the capacities used by the role.
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Goal
This activity aims at defining the complete life-cycle of a role by integrating previously identified RoleTasks, capacities, communications/conversations in which it is involved and the set of (or part of) requirements it has to fulfill. The behavior of the role is described by a set of AgentTasks and AgentActions. Role Behavior Description is a refinement at the Agent Society level of details of the results produced by the Role Plan activity during the System Requirements phase. Each RoleTask is refined and decomposed into a set of atomic behavioral units. The behavior of each role is now described using a state chart6. If a role requires capacities or provides services, this activity has to describe tasks and actions in which they are really used or provided.
Input
Role Behavior Description corresponds to a refinement of the work-product resulting from the Role Plan activity in which role behavior is described in terms of RoleTask. RoleTasks are then refined in AgentTasks and eventually decomposed into AgentActions. Capacity identification activity has already precise dependencies of the role. Invocations of previously identified capacities are integrated in AgentAction.
Output
Two approaches are used to represent role behavior. An activity based representation as presented in the Role Plan activity. In this activity, the role behavior is described using a state-based representation in terms of AgentRoleState.
MAS Meta-Model Elements
Define(AgentRole), Define(AgentTask), Define( AgentAction), Define(AgentRoleState), Relate(AgentTask, AgentAction), Relate(AgentRole, AgentTask), Relate(AgentRole, AgentRoleState).
Work to be done
The designer describes the dynamical behavior of the role starting from the Role Plan drawn in the previous phase and the capacities used by the role.
Suggested notation
Using a state-based approach for describing role behavior, state charts are well adapted to represent it. Moreover state-chart can be integrated in a global formal process based on OZS.
