Research Review: Application of Expert Systems in the Sciences

Studies from the field of artificial intelligence have given birth to a relatively new but rapidly growing technology known as expert systems. An expert system is a computer program which captures the knowledge of a human expert on a given problem, and uses this knowledge to solve problems in a fashion similar to the expert. The system can assist the expert during problem-solving, or act in the place of the expert in those situations where the expertise is lacking. Expert systems have been developed in such diverse areas as science, engineering, business, and medicine. In these areas, they have increased the quality, efficiency, and competitive leverage of the organizations employing the technology. During the 1980s, scientists and engineers have used this technology to search for oil, diagnose medical problems, and explore space. This paper provides an overview of this technology, highlights the major characteristics of expert systems, and reviews several systems developed for application in the area of science. OHIO J. SCI. 90 (5): 171-179, 1990 INTRODUCTION Expert system technology has captured the interest of professionals in a number of fields in recent years. Systems have been developed in such diverse areas as science, engineering, business, and medicine. Almost every professional and computer society currently has a special interest group for expert systems technology. This widespread interest can be attributed to the ability of the expert system to aid various organizations in solving practical, real-world problems. Currently, over two-thirds of the Fortune 1000 companies have expert system projects under development (Medsker et al. 1987). Organizations are looking toward these systems to aid them in increasing the quality, efficiency, and competitive leverage of their operations. During the 1980s, expert systems have been used in a wide range of applications in the area of science. Scientific and technology-oriented organizations have applied expert systems underground to find oil or mineral deposits (Duda et al. 1977), in space to help control various spacecrafts (Durkin and Tallo 1989), and on earth to help in diagnosing medical problems (Shortliffe 1976). Expert systems can aid scientists by interpreting data from an experiment, interact with a physician to identify a given disease, or aid an engineer in controlling a particular process. This paper provides an overview of this technology, highlights the major characteristics of expert systems, and reviews several systems developed for application in the area of science. The paper also includes a short bibliography on expert systems for the interested reader to explore further. EXPERT SYSTEM DEFINITION Expert systems are an offspring of the more general area of study known as artificial intelligence (Al). In the 'Manuscript received 24 January 1990 and in revised form 6 September 1990 (#90-2). simplest sense, Al is the study of developing computer programs which exhibit human-like intelligence. Early Al researchers focused on such problems as game theory, robotic control, and vision systems (Nilsson 1980). Common to each of these problems was research into ways of representing and reasoning with knowledge, in a computer, in a fashion similar to humans. The early studies in Al provided the insight needed to develop expert systems. In particular, these studies showed that reasoning alone is not a sufficient measurement of intelligent behavior, but rather, one had to have a rich set of knowledge with which to reason. It was also determined that the problem needed to be well-focused, using only the knowledge relevant to a specific problem. These two requirements led Al researchers to use human experts for their source of problem-solving knowledge. By virtue of being an expert, the human possesses unique talents, made possible by the human's knowledge and problemsolving skills on a particular subject. Because of the nature of these intelligent computer programs, they were aptly called expert systems (Feigenbaum 1977). An expert system is a computer program designed to model the problem-solving ability of a human expert. The program models the following characteristics of the human expert: Knowledge Reasoning Conclusions Explanations The expert system models the knowledge of the human expert, both in terms of content and structure. Reasoning is modeled by using procedures and control structures which process the knowledge in a manner similar to the expert. Conclusions given by the system must be consistent with the findings of the human expert. The expert system also provides explanations similar to the human expert. The system can explain "why" various questions are being asked, and "how" a given conclusion was obtained. One of the principal attractions of expert systems is that they enable computers to assist humans in many fields of 172 EXPERT SYSTEMS IN THE SCIENCES VOL. 90 endeavor with the processes of analyzing and solving complex problems. They extend the application of computers beyond the conventional mathematical processes we have customarily assigned computers, to applications where the computer can carry on a somewhat natural conversation with the user to arrive at a conclusion or recommendation that aids the human decision-maker. This is accomplished by encoding in the expert system the knowledge and problem-solving skills of a human expert. This expert computer program can then be used by others to obtain and use this expertise for solving a current problem that would have previously required the expert to be present. EXPERT SYSTEM STRUCTURE The structure and operation of an expert system are modeled after the human expert. Experts use their knowledge about a given domain coupled with specific information about the current problem to arrive at a solution. For example, a physician would possess knowledge about a variety of possible diseases and, coupled with specific information about a given patient, would be able to diagnose the patient's problem. Expert systems solve problems using a process which is very similar to the methods used by the human expert (see Fig. 1).