← IGCSE Computer Science Paper 1

Expert system interface

The part of an expert system the user sees. It shows questions, lets the user enter answers and facts, and displays the conclusion in a simple way for non-experts.

Part of: IGCSE Computer Science 0478 — 6.3 Artificial Intelligence — Module 15

Understanding Expert system interface in IGCSE Computer Science Paper 1

What it does: The conclusion reached by the inference engine is shown to the user through the interface. A plain Y/N question needs no expert knowledge, so a non-expert can answer it easily. The interface is the screen the user interacts with. Storing facts is the job of the knowledge base. Users type or select answers on the interface. They do not change the rules. Expert systems let non-experts get expert advice, so the screen must be simple and clear. Displaying questions to the user is the interface's job. Simple questions and choices help non-experts enter answers correctly.

Common mistakes: The conclusion must be shown to the user, so it needs OUTPUT. INPUT would wait for the user to type something instead. It should be OUTPUT "Check the battery". This displays the user's own answer instead of the conclusion. The interface should display the conclusion, OUTPUT "See a doctor".

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This module's key terms are also in a printable crossword (Modules 662–678) and word search (Modules 652–678).

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Learning

Duo

What is the interface of an expert system?

The part the user sees and uses to enter answers and read the conclusionThe part that stores all the expert's facts and rules

Matches

The interface stores the rules and facts that experts have collected

↓

This describes the knowledge base and rule base, not the interface. The interface only handles input and output between the user and the system.

Applying

Meanings

Term

user interface

Meaning

The part of an expert system the user sees. It shows questions, lets the user enter answers and facts, and displays the conclusion in a simple way for non-experts.

Practice

OUTPUT "Does the patient have a fever?"

Testing

Gaps

"Is the engine making a noise?"

Check Answer

Spots

3IF answer = "no" THEN

4 INPUT "Check the battery"

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Quick Questions

1. What is the interface of an expert system?

A. The part the user sees and uses to enter answers and read the conclusion ✓

B. The part that stores all the expert's facts and rules

The interface is the screen the user interacts with. Storing facts is the job of the knowledge base.

2. Which of these does the interface do?

A. Searches the rule base for a matching rule

B. Displays questions to the user ✓

The interface shows questions. Searching the rules is done by the inference engine.

3. How does a user give the expert system information about their problem?

A. By entering answers through the interface ✓

B. By editing the rule base directly

Users type or select answers on the interface. They do not change the rules.

4. Where does the user see the final result of an expert system?

A. The conclusion is displayed on the interface ✓

B. The conclusion stays hidden inside the inference engine

The interface displays the conclusion so the user can read it and act on it.

5. Why should an expert system interface be user-friendly?

A. So only trained experts can use it

B. So non-experts can use it without special training ✓

Expert systems let non-experts get expert advice, so the screen must be simple and clear.

Match the Pairs

Interface shows: "Does the patient have a fever? (Y/N)" → The interface displays a question to the user

INPUT answer → The interface lets the user enter an answer or fact

The interface displays the conclusion to the user once the system has finished reasoning → OUTPUT "Diagnosis: Flu"

A user-friendly interface lets non-experts choose from simple options instead of using technical terms → OUTPUT "Is the engine making a noise? (Y/N)"

The interface stores the rules and facts that experts have collected → This describes the knowledge base and rule base, not the interface. The interface only handles input and output between the user and the system.

The interface is designed so that only a trained expert can use it → The interface should be user-friendly for non-experts. Needing expert training defeats the purpose of an expert system.

Key Term

user interface

The part of an expert system the user sees. It shows questions, lets the user enter answers and facts, and displays the conclusion in a simple way for non-experts.

Fill in the Blanks

1. OUTPUT "Is the engine making a noise?"

Hint: Type the keyword that makes the interface display a question to the user.

2. OUTPUT "Is the engine making a noise?" INPUT answer

Hint: Type the keyword that lets the user enter their answer through the interface.

3. OUTPUT "Conclusion: Check the battery"

Hint: Type the keyword used to show the conclusion on the screen.

4. INPUT answer IF answer = "YES" THEN

Hint: Type the variable name that holds what the user entered.

5. OUTPUT "Enter symptom (YES/NO):" INPUT symptom

Hint: Type the keyword that reads a non-expert user's reply to a simple prompt.

Spot the Error

Question 1

A OUTPUT "Is the car starting?"

B INPUT answer

C IF answer = "no" THEN

D INPUT "Check the battery"

E ENDIF

Line D — The conclusion must be shown to the user, so it needs OUTPUT. INPUT would wait for the user to type something instead. It should be OUTPUT "Check the battery".

Question 2

A OUTPUT "Do you have a fever?"

B INPUT fever

C IF fever = "yes" THEN

D OUTPUT fever

E ENDIF

Line D — This displays the user's own answer instead of the conclusion. The interface should display the conclusion, OUTPUT "See a doctor".

Question 3

A OUTPUT "Is the rash itchy?

B INPUT reply

C IF reply = "yes" THEN

D OUTPUT "Try a cream"

E ENDIF

Line A — The question text is missing its closing quote, so the interface cannot display it properly. It should be OUTPUT "Is the rash itchy?".

Question 4

A INPUT "Welcome to Pet Help"

B OUTPUT "Is your pet a dog?"

C INPUT answer

D IF answer = "yes" THEN

E OUTPUT "Walk it daily"

F ENDIF

Line A — A welcome message is shown to the user, so it needs OUTPUT. INPUT is for the user entering answers. It should be OUTPUT "Welcome to Pet Help".

Question 5

A OUTPUT "Is the light on?"

B INPUT answer

C IF answer = "no"

D OUTPUT "Check the bulb"

E ENDIF

Line C — The IF line is missing THEN. The expert system can only act on the user's answer if the rule is written correctly: IF answer = "no" THEN.

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