FACET: an object-oriented software framework for modeling complex social behavior patterns GIS/EM4 No. 79

The Framework for Addressing Cooperative Extended Transactions (FACET) is a flexible, objectoriented architecture for implementing models of dynamic behavior of multiple individuals, or "agents", in a simulation. These agents can be human (individuals or organizations) or animal and may exhibit any type of organized social behavior that can be logically articulated. FACET was developed by Argonne National Laboratory's (ANL) Decision and Information Sciences Division (DIS) out of the need to integrate societal processes into natural system simulations. The FACET architecture includes generic software components that provide the agents with various mechanisms for interaction, such as step sequencing and logic, resource management, conflict resolution, and preemptive event handling. FACET components provide a rich environment within which patterns of behavior can be captured in a highly expressive manner. Interactions among agents in FACET are represented by Course of Action (COA) object-based models. Each COA contains a directed graph of individual actions, which represents any known pattern of social behavior. The agents' behavior in a FACET COA, in turn, influences the natural landscape objects in a simulation (i.e., vegetation, soil, and habitat) by updating their state. The modular design of the FACET architecture provides the flexibility to create multiple and varied simulation scenarios by changing social behavior patterns, without disrupting the natural process models. This paper describes the FACET architecture and presents several examples of FACET models that have been developed to assess the effects of anthropogenic influences on the dynamics of the natural environment.