System entity structuring and model base management

System entity structure (SES) is a structural knowledge representation scheme that contains knowledge of decomposition, taxonomy, and coupling of a system. Formally, the SES is a labeled tree with attached variable types that satisfy certain axioms. Described is a realization of the SES in Scheme (a Lisp dialect), that is called ESP-Scheme. Specifically, the computer representation of SES and main operations on SES are presented, and then facilities provided by ESP-Scheme are described. Two examples of application are discussed: a parallel processor model and a simulation study of a university phone registration system. ESP-Scheme acts as a model base management system in DEVS-Scheme, a knowledge-based simulation environment. It supports specification of the structure of a family of models, pruning the structure to a reduced version, and transforming the latter to a simulation model by synthesizing component models in the model base