Define Expert System with example. What are stages of expert system development ? Explain.

An expert system is a computer system whose performance is guided by specific, expert knowledge in solving problems. It is a computer system that simulates the decision-making process of a human expert in a specific domain. An expert system is an “intelligent” program that solves problems in a narrow problem area by using high-quality, specific knowledge rather than an algorithm. Expert systems are used by most large or medium-sized organizations as a major tool for improving productivity and quality. An expert system’s knowledge is obtained from expert sources and coded in a form suitable for the system to use in its process.

Examples:

MYCIN would attempt to diagnose patients based on reported symptoms and medical test results.

CALEX is a user-friendly computer program that simulates human problem-solving behavior. It is a blackboard-based integrated system for agricultural management. CALEX can be used by growers, pest control advisors, consultants, and other managers.

DENDRAL’s primary aim was to help organic chemists in identifying unknown organic molecules, by analyzing their mass spectra and using knowledge of chemistry.

Emycin is an expert system, a framework for building programs that record the knowledge of domain experts and use that knowledge to help non-expert users solve problems.

Stages of Expert System Development:

Identification

• The problem must be suitable for an expert system to solve it.
• Find the experts in the task domain for the ES project.
• Establish the cost-effectiveness of the system.

Conceptualization

• Identify the ES Technology.
•  Know and establish the degree of integration with the other systems and databases.
• Realize how the concepts can represent the domain knowledge best.

Formalization

• The various techniques of knowledge representation and heuristic search are used in expert systems.
• The expert system tools can greatly assist the development process.
• Other expert systems may solve similar problems and thus may be adequate for the problem at hand.

Implementation

During the implementation stage, the formalized concepts are programmed onto the computer that has been chosen for system development, using the predetermined techniques and tools to implement a first-pass prototype of the expert system.

Testing

Testing provides opportunities to identify the weakness in the structure and implementation of the system and to make the appropriate corrections.
Depending on the types of problems encountered, the testing procedure may indicate that the system was proper.