Chapter 5.1 Expert systems

Question 1

What is an Expert system?

Answer 1

1 An expert system is a devised system or computer software that has been developed to act like a human expert on a particular subject or field.
2 Expert systems are often used to advise non-experts in situations where a human expert is unavailable.

Question 2

How does a basic system work?

Answer 2

A basic expert system is made up of the following elements:

              Query  Non expert  -----> User        ------->Inference

Question 3

Give examples where expert systems are used

Answer 3

1. Diagnosing a person’s illness
2. Complex “thinking” tasks such as chess games
3. Tax and financial calculations
4. Identification of plants, animals and chemical compounds
5. Prospecting for oil, water or minerals

Question 4

Explain how expert systems are used to Diagnosing a person’s illness?

Answer 4

In this medical expert system, the knowledge base would contain medical information, the symptoms of the patient would be used as the query, and the advice would be a diagnose of the patient’s illness.

Question 5

Explain how expert systems are used to do Complex “thinking” tasks such as chess games?

Answer 5

In this typical chess game expert system, the knowledge base would contain strategies and moves, the player’s moves would be used as the query, and the output would be the computer’s ‘expert’ moves.

Question 6

Explain how expert systems are used to do Tax and financial calculations?

Answer 6

In this kind of tax expert system, the knowledge base would contain data about the performance of financial markets and businesses in the past, contributions as query and output whether to invest or not.

Question 7

Explain how expert systems are used to Identify plants, animals and chemical compounds?

Answer 7

The knowledge base would contain characteristics of every item, the details of an unknown item would be used as the query, and the advice would be a likely identification.

Question 8

Explain how expert systems are used for Prospecting for oil, water or minerals?

Answer 8

The knowledge base would contain characteristics of likely rock formations where oil / water could be found, the details of a particular location would be used as the query, and the advice would be the likelihood of finding oil / water there.

Question 9

How are Expert Systems created?

Answer 9

1 Interview with the experts
- Experts in a field are interviewed and their knowledge is collected.
2 Knowledge base is created
- All of the knowledge collected from the expert are organized and stored in the knowledge base.
- The knowledge base is searched by the inference engine.
3 Inference engine is created.
- This allows the knowledge based to be searched by the user. The inference engine poses questions to the user and then analyses the answers by running a set of rules that have been entered in the system.
4 User interface is created.
- This allows the user to communicate with the expert system. They allow the users to answer questions posed by the system. Common ways to answer them are checkboxes, textboxes or submit buttons.
5 Testing
- Finally the expert system is tested to see if the correct answers are being generated for the questions.

Question 10

Advantages of expert systems

Answer 10

1 Provides consistent answers
2 Never “forgets” to ask a question in determining the logic
3 Reduces the time taken to solve a problem
4 Less skilled work force needed, therefore potentially can save money

Question 11

Disadvantages of expert systems

Answer 11

1 Lacks common sense in some of the decision making processes
2 Errors in the knowledge base can lead to incorrect decisions being made
3 Cannot adapt to changing environments unless the knowledge base is continually updated
4 Expensive system to set up in the first place
5 Needs considerable training to ensure system used correctly by operators