Chapter 12 Fundamentals of Expert Systems.ppt

Chapter 12: Fundamentals of Expert Systems 12.1 Opening Vignette: CATS-1 at General Electric The Problem General Electrics (GE) Top Locomotive Field Service Engineer was Nearing Retirement Traditional Solution: Apprenticeship Good Short-term Solution BUT GE Wanted A more effective and dependable way to disseminate expertise To prevent valuable knowledge from retiring To minimize extensive travel or moving the locomotives The Expert System Solution To MODEL the way a human troubleshooter works Months of knowledge acquisition 3 years of prototyping A novice engineer or technician can perform at an expert’s level On a personal computer Installed at every railroad repair shop served by GE 12.2 (ES) Introduction Expert System: from the term knowledge-based expert system An Expert System is a system that employs human knowledge captured in a computer to solve problems that ordinarily require human expertise ES imitate the expert’s reasoning processes to solve specific problems 12.3 History of Expert Systems 1. Early to Mid-1960s One attempt: the General-purpose Problem Solver (GPS) General-purpose Problem Solver (GPS) A procedure developed by Newell and Simon [1973] from their Logic Theory Machine - Attempted to create an intelligent computer Predecessor to ES Not successful, but a good start 2. Mid-1960s: Special-purpose ES programs DENDRAL MYCIN Researchers recognized that the problem-solving mechanism is only a small part of a complete, intelligent computer system General problem solvers cannot be used to build high performance ES Human problem solvers are good only if they operate in a very narrow domain Expert systems must be constantly updated with new information The complexity of problems requires a considerable amount of knowledge about the problem area 3. Mid 1970s Several Real Expert Systems Emerge Recognition of the Central Role of Knowledge AI Scientists Develop Comprehensive knowledge representation theories General-purpose, decision-making