Expert System is a class of software systems that emulates the knowledge and behavior of human experts to solve a problem. The expert system has a long history in the field of computing since 1970. It was hyped in a big way, in its initial days of evolution but could not keep its promises in the subsequent years. With successful developments in computational intelligence technologies, expert system and other AI systems have made a comeback to find a meaningful place in information systems, which are becoming more and more intelligent with every passing day. This article provides a refreshing introduction to expert system and discusses how to develop it using JESS.

Expert System is a branch of Artificial Intelligence (AI). It was developed by researchers during 1970s and applied commercially throughout the 1980s. Expert system is a computer program that emulates the decision-making of a human expert in narrow domain of expertise such as diagnosing a heart disease, predicting a stock in the stock market, etc. Expert system reasons by heuristics or approximate methods. It explains and justifies solutions in user-friendly terms. One of the early expert systems with a visible success story was MYCIN, a program for diagnosing bacterial infections in blood cells. Most of the successful expert systems were built around rules for medical diagnosis, engineering, science, and business applications. Expert systems had a number of perceived advantages over human experts. For instance, unlike people, they could perform at the peak of efficiency, 24 hours a day, throughout the year without fatigue. There are numerous dramatic examples in the computer science literature of these early systems matching or exceeding the performance of their human counterparts in specific and limited situations. Predictions were made that sophisticated expert systems would be able to reproduce general human intelligence and problem-solving abilities. Over time, the hype receded, and it was understood that researchers had vastly underestimated the complexity of the common-sense knowledge that underpins general human reasoning. Nevertheless, excellent applications for expert systems remain to see this day.

Expert System Using JESS, software systems, knowledge and behavior, computational intelligence technologies, information systems, Artificial Intelligence (AI), decision-making, medical diagnosis, human intelligence, problem-solving abilities.