On-line Planning Simulation

MESS is a substrate for building simulation environments suitable for testing plans and on-line or real-time planners. The article describes the design of MESS, how simulations are built and how on-line planners integrate with the substrate. MESS supports activities, defined as processes over some time interval, and interactions between activities and other simulation events. MESS interfaces with TCL, which is a portable, extensible definition of computation time, enabling MESS to be used for platform-independent simulations of real-time planning. MESS has been used to re-implement the PHOENIX testbed, which simulates forest fires and planning for fire-fighting agents.