System Dynamics

Abstract

System dynamics provides an approach to analyzing and developing models that represent the dynamic behavior of systems over time. A system is a collection of interacting components that together are capable of some functionality. Systems may exist naturally in the physical world or social and political domains, or they may be designed and built explicitly by humans. System dynamics models begin with stocks and flows. Stocks are used to represent any entity in a system that accumulates or depletes over time and flows are used to model the transfer of contents between stocks or into or out of a stock over time. System dynamics also includes representations of feedback loops and time delays that model or simulate the ways that system components interact and result in a simulation of the behavior of the entire system. Feedback loops allow for the system simulation to adjust its behavior based on the measured output of the system in the simulation. The objects being modeled with their behaviors, interactions and relationships represent a system, which is composed of interdependent components. This chapter will give an overview of System Dynamics, and discuss modeling approaches for decomposing the system into components and identifying connections and interactions among individual elements. It will also present techniques and tools for representing the interconnections and behaviors of system elements both visually and computationally.