24-11-2012, 05:46 PM
Expert Systems Artificial Intelligence
07_Expert_Systems.doc (Size: 681.71 KB / Downloads: 101)
What is Expert System ?
• An expert system, is an interactive computer-based decision tool that
uses both facts and heuristics to solve difficult decision making problems,
based on knowledge acquired from an expert.
• An expert system is a model and associated procedure that exhibits,
within a specific domain, a degree of expertise in problem solving that is
comparable to that of a human expert.
• An expert system compared with traditional computer :
Inference engine + Knowledge = Expert system
( Algorithm + Data structures = Program in traditional computer )
• First expert system, called DENDRAL, was developed in the early 70's at
Stanford University.
Introduction
Expert systems are computer applications which embody some non-algorithmic expertise for solving certain types of problems. For example, expert systems are used in diagnostic applications. They also play chess, make financial planning decisions, configure computers, monitor real time systems, underwrite insurance policies, and perform many services which previously required human expertise.
Expert System Components And Human Interfaces
Expert systems have a number of major system components and interface with individuals who interact with the system in various roles. These are illustrated below.
Expert System Shells
Many expert systems are built with products called expert system shells. A shell is a piece of software which contains the user interface, a format for declarative knowledge in the knowledge base, and an inference engine. The knowledge and system engineers uses these shells in making expert systems.
AI - Expert system - Introduction
■ Ability to Explain Reasoning
‡ Remembers logical chain of reasoning; therefore user may ask
◊ for explanation of a recommendation
◊ factors considered in recommendation
‡ Enhances user confidence in recommendation and acceptance of
expert system
■ Domain-Specific
‡ A particular system caters a narrow area of specialization;
e.g., a medical expert system cannot be used to find faults in an electrical circuit.
‡ Quality of advice offered by an expert system is dependent on
the amount of knowledge stored.
■ Capability to assign Confidence Values
‡ Can deliver quantitative information
‡ Can interpret qualitatively derived values
‡ Can address imprecise and incomplete data through assignment
of confidence values.