To build an expert system, the following prerequistes have been delineated:

• There must be at least one human expert acknowledge to perform the task well.
  
  
• The primary source of the expert's exceptional performance must be special knowledge judgement, and experience.
  
  
• The expert must be able to explain the special knowledge and experience and the methods used to apply them to particular problems.
  
  
• The task must have a well-bounded domain of application.
  
  

Design of Expert system