Prasenjit nath (mca, ugc-net) Abstract

MYCIN has three sub-systems:

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  Consultation system :
  

Works out possible organisms and suggests treatments.

• 
  Explanation System :
  

MYCIN can answer questions about HOW a conclusion was reached and WHY a question was asked, either after a consultation or while it is going on.
It does this by manipulating its record of the rules it invoked, the goal it was trying to achieve, the information it was trying to discover.
Can also answer general questions (e.g. what would you prescribe for organism X?) by consulting its static data structures.

• 
  Rule Acquisition system :
  

Experts can enter new rules or edit existing rules. The system automatically adds the new rule to the LOOKAHEAD list for all parameters mentioned in its premise, and to the UPDATED-BY list of all parameters mentioned in its action.
Control structure
MYCIN first attempts to create a “patient context" containing information about the case, then tries to compile a list of therapies for the context.
It uses a backward chaining mechanism, reasoning back from the goals it wants to prove to the data it has, rather than vice versa. The overall goal is "compile a list of therapies".
Questions can be prompted by the invocation of rules, to find out necessary data, to avoid unnecessary questions.
The EMYCIN (Essential MYCIN) expert system shell, employing MYCIN's control structures was developed at Stanford in 1980. This domain-independent framework was used to build diagnostic rule-based expert systems such as PUFF, a system designed to interpret pulmonary function tests for patients with lung disease.

4. 
   CASNET/Glaucoma:
   

CASNET (Causal Associational NETworks) developed in the 1960s, was a general tool for building expert system for the diagnosis and treatment of diseases. The most significant Expert System application based on CASNET was CASNET/Glaucoma for the diagnosis and treatment of glaucoma.
Expert clinical knowledge was represented in a causal-associational network (CASNET) model for describing disease processes. CASNET/Glaucoma was developed at Rutgers University and implemented in FORTRAN.

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