Aug 1998 SW204: Software And Files Design (Question 5) Suggested Solutions

5.	(a) Define the term artificial intelligence.		[2]
	Artificial intelligence is the branch of computer science which is concerned with the design of systems which exhibit characteristics of human behaviour (1 mark), such as language, learning, and reasoning (1 mark). Other sensible answers should also receive credit.
	(b) Almost all artificial intelligence programs contain problem solving techniques. Describe – using examples – the three components of a problem solving technique, and how they relate to one another.		[8]
	One mark should be awarded for naming each component, and a further mark should be awarded for a satisfactory elaboration – provided that a suitable example is given. Examples include the following: The database (1 mark). This contains knowledge, which can be stored in different forms; for example, in the case of robotics, a set of formulae and physical constraints may be used to represent surroundings (1 mark). A set of operators (1 mark). These are used to manipulate data via rules of inference; for example, rules of inference are used in theorem proving (1 mark). A control strategy (1 mark). This determines which operator to apply next, and how to apply it; for example, heuristics may be used to choose most promising candidate for the next operator (1 mark). Other sensible answers should also receive credit. Two marks are also available for a correct explanation of the relationship between the entities: A set of operators works on a database (1 mark), while a control strategy makes decisions based on the knowledge that is available (1 mark). Other sensible answers should also receive credit.
	(c)	(i) Why are techniques which are applied on game playing similar to those applied in problem solving?	[2]
		One mark should be awarded for each of the following points: A state tree is generated, with the initial state represented by a root and each position represented by a node. Each move in the game leads to the generation of other nodes (new game position); the goal of each player is to reach the final position (winning position) before his or her opponent does.
		(ii) Describe two points at which heuristic information can be applied in a search.	[2]
		One mark should be awarded for each valid point (up to a maximum of two marks). Examples include the following: Deciding which node to expand next, instead of doing the expansions in a strictly breadth-first or depth-first order. Deciding which successor or successors to generate in the course of expanding a node, instead of blindly generating all possible successors at once. Deciding that certain nodes should be discarded or pruned from the tree. Other valid answers should also receive credit.
		(iii) In the context of games, what is the alpha-beta principle?	[2]
		The alpha-beta principle dictates that whenever one discovers a fact about a node, one should check what is known about its ancestor nodes (1 mark). The approach uses two parameters – alpha and beta – which keep track of expectations (1 mark). Other sensible answers should also receive credit.
	(d) In recent years, artificial intelligence has progressed to a point at which machines and software have been developed that can actually perform better than human beings at certain tasks. Such events have been widely reported: one example is the Deep Blue chess computer, which was developed by IBM. Based on your understanding of artificial intelligence, describe whether you think – in your opinion – that it is possible for machines incorporating artificial intelligence to be superior to human beings at any, some, or even many tasks.		[4]
	This is a very subjective question, which aims to test the candidates’ understanding of the relevant issues. As such, marks should be awarded on the following basis: No marks should be awarded if the candidate demonstrates no understanding of the relevant issues. One mark should be awarded if the candidate demonstrates nominal understanding of the relevant issues. Two marks should be awarded if the candidate demonstrates good understanding of the relevant issues. Three marks should be awarded if the candidate demonstrates good understanding of the relevant issues, with discussion of advantages and / or disadvantages. Four marks should be awarded if the candidate demonstrates good understanding of the relevant issues, with discussions of advantages and / or disadvantages, and presents a suitable conclusion.