April 1999
SW204: SOFTWARE AND FILES DESIGN

QUESTION 5

Total Marks: 20 Marks

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GRADE A
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(a) Searching algorithms form the basis of Artificial Intelligence programs used in problem solving. Two categories of searching algorithms are blind search algorithms and those which employ heuristic methods.
(i) Name two blind search algorithms. [2]
Breadth - First Search
Depth - First Search

 
(ii) For each algorithm named in part (i), identify one advantage and one disadvantage. [4]
Breath - First Search algorithm
Advantages :
The breadth-first search will not get trapped exploring a blind alley because node of each level is explored before the new level s generated.

Disadvantages :
Redundant operation is required to generate all successors at each level. Movement from node to node involves performing some operation on parents node.
To return from children node to parents node, that operation must be repeated.

Depth - First Search algorithm
Advantages:
The depth-first search required less memory because only node on the current path is stored. This is contrast with the depth-first search where all part of the tree has generated so far has been generated must be stored.

Disadvantages:
The path used in the program might not be the quickest path.

 
(iii) State two differences between a heuristic search and a blind search. [2]
Heuristic Search Blind Search
execute ordered path to reached a goal the path may search level by level or along one path until the goal is reached.
an economical path is formed as there is a reducing in the searching time. searching might increased the number of calculation to reach a goal.

 
(iv) List two advantages of a heuristic search. [2]
Find the most economical path.
Reduce searching time.

 
(b) The representation of knowledge in Artificial Intelligence is a combination of data structures and interpretive procedures.
(i) How should knowledge be applied in Artificial Intelligence? [3]
  1. Acquisition of knowledge.
  2. Retrieving facts.
  3. Reasoning

 
(ii) Name the classical approach to representing knowledge in Artificial Intelligence. [1]
The classical approach to representing knowledge in Artificial Intelligence is : - Logic.

 
(iii) List two advantages of using the classical approach. [2]
  1. Used of a set of rules, that is rules of inference in logic to represent the formal representation.
  2. The rules that are known to be true can be used to derive other rules that must also be true.

 
(c) (i) Define the term expert system. [1]
Expert system is a branches of Artificial Intelligence. It emulates the reasoning power of human expert in subject domain.

 
(ii) List the three essential elements of an expert system. [3]
The three essential elements of an expert system are :-
  1. Knowledge base(KB)
  2. Inference Engine
  3. The user interface