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Thread: expert system - need help clarifying the concept

  1. #1 expert system - need help clarifying the concept 
    New Member
    Join Date
    Sep 2007
    Hi - I hope this is an appropriate forum for a layman to ask a basic question about the scope of the term "expert system".

    I have developed a simple program to assist pathologists when looking at skin diseases under the microscope and would like to know how it would be classified according to computer science AI or Expert System terminology, if at all.

    I have implemented this using Microsoft Access. Every skin disease can be described by two or more features, some diseases have up to 60 or more features. Some features are unique to a disease, most are not; that is, most of the features are present in numerous skin diseases. For every disease each feature is specified as present or absent. The program works by allowing the user to select features (both present and absent) from various lists of features and creates SQL queries to extract diseases that have these features. The diseases are then ranked according to the number of features it matches. The user is free to choose any number and combination of features whatsoever and the SQL search engine will find whatever matches.

    From my understanding, this is not an expert system since, altho the knowledge is encoded in the data, the expertise is not coded at all - ie there is no inference engine composed of "if ... then" statements.

    How would something like this be classified in the computer science scheme of things?

    Thanks, Jim Gallagher

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  3. #2  
    WYSIWYG Moderator marnixR's Avatar
    Join Date
    Apr 2007
    Cardiff, Wales
    the 2 basic ingredients of an expert sytem are a knowledge base and an inference engine, which when combined mimic an expert's reasoning process

    what you describe there seems to fit this description pretty well - after all, you must have gone through some sort of inference process when recognising certain suites of features in your SQL query

    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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  4. #3  
    Join Date
    Apr 2007
    I'm not a computer person, so I probably shouldn't even be answering this. But a lack of knowledge never deters anybody else here.

    I'd say you have a database that is probably a very useful diagnosis tool. I may be wrong but suspect a true expert would not make the diagnosis just on the basis of number of matching features. Some are probably more important than others.

    What you are putting together sounds similar to the Mycin expert system except Mycin seems to have a bit more complex inference engine
    It would query the physician running the program via a long series of simple yes/no or textual questions. At the end, it provided a list of possible culprit bacteria ranked from high to low based on the probability of each diagnosis, its confidence in each diagnosis' probability, the reasoning behind each diagnosis (that is, Mycin would also list the questions and rules which led it to rank a diagnosis a particular way), and its recommended course of drug treatment.
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