ESL: an actor-based platform for developing emergent behaviour organisation simulations

Specification and analysis of complex systems can be approached top-down or bottom-up [11]. A top-down approach conceptualises a system using a global state and the behaviour represented using an aggregated macro-behaviour of the system elements. For example, the System Dynamics (SD) model [8] uses the concepts of stocks, flows, feedback loops and time delays. A top-down approach considers a reductionist view [10] to understand system using the mathematical rigour from operational research, optimization theory, and sophisticated AI algorithms. A bottom-up approach, in contrast, considers the micro-behaviour of individual elements and their interactions. Conceptually, the bottom-up approach relies on emergentism [9] as advocated in actor model of computation [1], and agent-based systems [6].