Diagnosis is the study of build knowledge system of specific problems, such as medicine or science. The purpose of this system is to make the virtual human experts to assist and answers about the issue of various
.In this research the main purpose that we don't have to rely on human problem solving. However, in practice the expert system also need to rely on humans to provide basic knowledge in the beginning.Whether it is knowledge representation.Reasoning, and machine learning. Examples of this kind. Application expert system for diagnosis or MYCIN infectious diseases through blood.