Expert Systems

Expert Systems (Shells) vs Relational Database

"An expert system is a program that contains the specialist knowledge of one or more human experts.
This expert knowledge is in a form that others may use to solve problems in a specific domain.
The expert system provides the user with advice and can explain the advice it gives and why it is asking particular questions.
Expert systems must be able to handle uncertain and incomplete information".

In this unit, Intermodellar (an Expert System shell - a program containing an empty knowledge base, a pre-defined user interface and an inference engine) has been used to create expert systems that, hopefully, hit the definition above. But what about a RDBMS, could it do the job?

Comparison of Data Representation and Information Retrieval

An Expert system stores data in its knowledge base as production rules. To query the system involves a consultation being run, wheerby the user is asked questions via the user interface until eventually advice is provided.

A RDBMS stores data in related tables, as records and fields (attributes). Querying the system is a matter of running a search and entering the appropriate criteria in the required field(s). The system will then return the relevant data. This may prove a quicker process than using a shell, where many questions may have to be posed, but could involve a greater degree of competence on the part of the user to extract the required information from the system. Creating Why and How justification can be a very complex operation to undertake in a RDBMS, whilst these features are in-built aitomatically in a shell.

 

Sample Question and Solution

2006 q.24 d. Distinguish between an expert system and a relational database in terms of how data is represented and the method of querying. (4)

An expert system shell represents data by storing it in its knowledge base as a series of production rules (IF statements using various conditions).
In a relational database, data is stored in one or more related tables as a set of records each containing a set amount of fields.

The expert system is queried by running a consultation of the system, resulting in the user having to answer a series of questions in the user interface, until such time that the answers provided allow the system to display advice to the user in the same user interface.
In a relational database, a query is created allowing the user to enter serach criteria in their chosen fields to immediately produce a sub-set of records which match the search criteria.

A Deductive Database

A RDBMS is a powerful tool as is an expert system shell. Combining the two would produce a real superhero then, no?

A deductive database is a tool which combines the the data handling and searching capabilities with the inferencing powers of an expert system. The relational database stores the information and the expert system inference engine uses the information to provide advice.

Expert Systems (Shells) vs Decision Support System

A decision support system is a mechanism for collating information that is used as part of the process by users allowing them (the user) to make decisions.
An expert system is designed to provide the actual advice that is used to treat a patient.
It uses a knowledge base of facts and rules, and from such the experts system itself infers new knowledge. Expert systems make decisions, decision support systems do not.

Comparing Systems Regarding Expert Systems