Catalogue of Artificial Intelligence Techniques
Expert System Shell
Keywords: EMYCIN, MYCIN, Prospector
Categories: Expert Systems
Author(s): Max Bramer
A shell is a domain-independent Expert Systems `framework', i.e., an inference engine with explanation facilities etc. but without any domain-specific knowledge. Provided the framework is a suitable one for a given problem, it may be possible by adding domain-specific knowledge to build a new Expert System with much less effort than beginning from scratch. On the negative side, the use of a shell imposes a number of design decisions on, for example, the form in which knowledge is represented (it may be that only Production Rules are catered for), and the means by which reasoning with uncertain knowledge is handled (e.g., Bayesian Inference, Dempster-Shafer Theory, etc.). These can considerably reduce the range of applicability of a particular shell. Commercial shells are generally readily available for standard business computers (such as IBM PCs) but typically little or no attempt is made by suppliers to identify the range of applicability of their products. Shells developed for research purposes (e.g., EMYCIN based on MYCIN, and KAS based on Prospector) generally offer more sophisticated facilities, but are frequently difficult to obtain outside the academic research community, are often poorly documented and even when available may be difficult to transfer to new systems.
- Hayes-Roth, F., Waterman, D.A. and Lenat, D.B., eds., Building Expert Systems
, vol. 1, Addison-Wesley, Reading, Mass., 1983.