Abstract for: A New Entity-Based System Dynamics Tool

Emerging needs for modeling large and complex systems require a new modeling language and platform that is based on system dynamics but that is designed from the ground up to support hierarchical and object oriented modeling. We describe a new platform for system dynamics modeling that supports detailed and object oriented modeling while preserving attractive features of existing tools, including a completely declarative language with a graphical representation. New concepts supporting this platform include collections of entities, attributes, relationships, aggregation and allocation functions, and actions, which are presented with examples. A graphical language extends stock-flow diagrams to include the new concepts. The design facilitates modularity and collaboration, provides a more natural description of detail than arrays, and solves sparse matrix problems. It has application to both traditional system dynamics, with modular sectors, and to agent based modeling.