TCB3343 Artificial Intelligence / Sept 2014

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TCB3343 Artificial Intelligence

Exercise 5: Expert Systems

1. a. Consider the following information used for diagnosing respiratory system

diseases given patient symptoms:

Influenza: Symptoms include dry cough and feeling of general malaise.

Hayfever: Symptoms include dry cough, fever, runny nose and sneezing. The

patient will show a positive reaction to allergens such as dust or

pollens.

Laryngitis: Symptoms include dry cough, fever and feeling of general malaise.

A positive result of larynscopy test will reveal that the patient has an

Inflamed Larynx.

Asthma: Symptoms include dry cough, breathlessness and wheezing. If it is

triggered by allergens such as dust or pollens, it is likely to be

Extrinsic Asthma while Intrinsic Asthma tends to be triggered by

exercise, smoke or respiratory infection.

Using the above knowledge of typical symptoms, develop:

i. A set of independent production rule for each possible disease.

ii. Based from your answer in part (a)(i), combine those independent rules

into a nested rule.

2. You are given a set of rules:

RULE 1: IF a person has RM 1000 to invest AND has a college degree

THEN the person should invest in securities

RULE 2: IF a person’s annual income >= RM 40000 AND has a college degree

THEN the person should invest in growth stocks

RULE 3: IF a person is younger than 30 AND is investing in securities

THEN the person should invest in growth stocks

RULE 4: IF a person is younger than 30 AND older than 22

THEN the person has a college degree

RULE 5: IF a person wants to invest in growth stock

THEN the stock should be IBM

Assume that an investor has RM 10000 and she is 25 years old. Using forward chaining inference

technique, advice whether she should invest in the IBM stock or not.

TCB3343 Artificial Intelligence / Sept 2014

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3. Suppose a backward chaining system is using these rules to prove a fire hazard when combustible

gas, electricity and oxygen are present. Show whether the fire hazard is a reachable conclusion?

RULE 1: If fuel AND heat AND oxygen THEN fire

RULE 2: IF solid OR combustible THEN fuel

RULE 3: IF gas AND combustible THEN fuel

RULE 4: IF flame THEN heat

RULE 5: If electricity THEN heat

RULE 6: IF friction THEN heat

4. The data in FIGURE Q4 are used in a Rule-Based Expert System.

FIGURE Q4

Show clearly the match-fire procedure and the database update (in each cycle or pass) to

find the goal fire using the following inference techniques:

a. Forward Chaining

b. Backward Chaining

KNOWLEDGE BASE IF smoky AND hot THEN fire IF coughing THEN smoky IF aircond_broke THEN hot IF dusty THEN coughing AND machine_failed IF wiring_failed AND machine_failed THEN aircond_broke

DATABASE dusty wiring_failed