What is Expert system?
An '''expert system''' is a [[computer program|program]] running on a [[computer]]. Like a [[human]] [[expert]], it knows a lot about a subject. People can ask the expert system a question. The expert system will then use a set of [[rule]]s and give answers to the question. This method of automated reasoning belongs to a field of [[computer science]] called [[artificial intelligence]]. Different groups of people can have different kinds of access to an expert system. The people managing the [[network]] of computers have different needs than the office worker or secretary. ==How expert systems work== Expert systems are made of *A set of facts, rules and principles *A set of data that is solved using its expertise *A user interface When they are asked a question, they will filter the data with the rules they have. They might give back a result, or ask an additional question. ==Categories of expert systems== *[[Case-based reasoning|Case-based]] expert systems have a number of cases; each case describes the problem in context, and the solution of the problem, in the specific case. The current problem is matched as closely as possible to a case. The solution of the case found is then applied to the current problem. The main problem of such systems is to define how cases relate to each other, or are similar. An example of where such a system may be used is that of a [[patient]]: This patient shows a given number of [[symptom]]s, and the expert system could diagnose the patient. *Rule-based systems do not rely on cases; instead, there are a number of rules. These are expressed in the form ''IF A THEN B''. In most systems, human experts have to write the rules. *A third approach is to construct systems that are based on [[decision tree]]s. Such systems are capable of [[machine learning|learning]], or of extending their knowledge base, using [[inductive reasoning]]. When the classification is done, the system uses a path through the tree. At the end, it arrives at a leaf, which indicates the class of solution to th