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Unformatted text preview: Artificial Intelligence 2007 Spring Midterm Solution May 31, 2007 1. (10 points) Minesweeper is a famous one-player computer game as shown in Figure 1. The player has to find all the mines in a given minefield without detonating anyone of them. Suppose you are asked to design an intelligent agent to play a minesweeper game, develop the PEAS description of this task.(Hint: P: Performance, E: Environment, A: Actuators, S: Sensors) Figure 1: A minesweeper game Answer Performance Time spent, Score gained Environment Minefield, Cells Actuators Mouse Sensors Camera 2. (15 points) Given a Tree G ( V,E ) as Figure 2. Let the depth for node v ∈ V be d ( v ), and edge cost for edge e ∈ E be g ( e ). (a) (3 points) In what case that Uniform-cost search will be identical to BFS? (b) (5 points) List the order in which nodes will be visited from node 1 to 11 using iterative deepening search. (c) (7 points) Best-first search is an algorithm that a node v is selected for expansion based on an evaluation function f ( v ). Show that BFS, DFS are special cases of Best-first search. Answer (a) When the costs for each step are the same. (b) 1,1,2,3,1,2,4,5,3,6,7,1,2,4,8,9,5,10,11 (c) When f ( v ) = d ( v ), Best-first Search acts the same as BFS. When f ( v ) = 1 /d ( v ), Best-first search acts the same with DFS. Thus BFS and DFS are all special cases of Best-first search. 3. (20 points) Consider the problem of moving k knights from k starting squares s 1 ,s 2 ,...,s k to k goal squares g 1 ,g 2 ,...,g k , on an unbounded chessboard, in the smallest number of actions. Each 1 Figure 2: G ( V,E ) Figure 3: Legal moves of a knight on the chess board. action consists of moving from 0 to k knights simultaneously, subject to the rule that no two knights can land on the same square at the same time. The legal moves of a knight are marked in Figure 3....
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- Spring '11
- Search algorithm, Constraint satisfaction, heuristic function, Admissible heuristic, Consistent heuristic