Briefly discuss expert systems.

An expert system is an attempt to make a computer an expert in one narrow field. Both facts and rules about how the facts are used to make decisions in the field are entered in the computer. Expert systems are a branch of artificial intelligence, which examines how computers behave like human beingsthat is, in intelligent ways.
Expert systems have been used in medicine since the 1950s. They are meant to be decision support systems, which help, but do not replace, medical personnel. They are especially useful when there is a limited, well-defined area of knowledge needed for a decision that will be based on objective data. The doctor enters symptoms, test results, and medical history. The computer either asks for more information or suggests a diagnosis and, perhaps, treatment. Some systems give the diagnosis in the form of a probability.