Modelling Environments in ABMS: A System Dynamics Approach

Environment is a basic concept of agent-based modeling and simulation (ABMS), in which agents exist and interact, can perceive and act. Common approaches to model environment in ABMS consider environment as a physical space (typically a 2D grid) or as a virtual space that supports agent to agent interaction. In this paper, we introduce a method for modeling the environment in agent-based simulations that integrates both its physical and social aspects. Borrowing from System Dynamics, we specify environment as a set of stocks and flows. Stocks represent physical resources, spatial locations and social structures in a uniform way. Stocks can be perceived and modified by agents through flows. Our method considers and describes the environment as a combination of spatial space (or network), physical structure, and social structure, which makes the inter-relation between the global state environment variables and the behavior of the agents explicit. We illustrate the use of the method through its application to a case study in consumer lighting.