Expert Systems

Abstract

Expert systems, or more appropriately knowledge‐based systems, are essentially computer programs that encode the expertise of human problem solvers in some well‐defined domain. A practical offshoot of the field of artificial intelligence, knowledge‐based technology has emerged as an important area of computer applications, with significant business impact on the industry. This is because knowledge‐based systems can automate problem‐solving tasks that hitherto could not be computerized by conventional, numeric modeling techniques. In the domain of chemical engineering, knowledge‐based systems have been used to automate such tasks as equipment and process design, control of complex processes, troubleshooting process operations, scheduling batch processes under uncertain conditions, and simulation of discrete event operations. This article discusses the motivations and benefits of knowledge‐based technology as applied to chemical engineering problems; the differences between knowledge‐based systems and quantitative, numerical techniques; the theoretical underpinnings of the technology; approaches to selecting, designing, and implementing knowledge‐based system applications; and some of the tools available to implement such systems. Alternatives to expert systems such as neural networks (nets) and case‐based reasoning are also briefly discussed. Throughout, the concepts are illustrated using examples from chemical engineering.