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**Unformatted text preview: **Faculty of Engineering- Alexandria University
Computer &Systems Eng Dept
Lecturer
Course
Code
Date : Dr. Amin Shoukry
: Artificial intelligence
:
: November 2009 Marks :
Time : 1 Hr Take Home Exam
Answer all Questions:
Q. 1 Consider the tree shown below. The numbers on the arcs are the arc lengths; the
numbers near states B, C, and D are the
heuristic estimates; all other states have a
heuristic estimate of 0.
Assume that the children of a node are
expanded in alphabetical order when no other
order is specified by the search, and that the
goal is state J.
What is the sequence of states expanded by
the following search techniques ?
- Uniform Cost
- Best First
– A*
Q. 2 Consider the undirected graph shown below. The numbers
on the arcs are the arc lengths. Let A be the start state and G be the
goal state. Assume you
are using a heuristic function h(n) that gives the following heuristic
values:
h(A) = 5; h(B) = 4; h(C) = 0; h(G) =0 .
a) Apply the A* algorithm to obtain the optimal path.
b) Is this heuristic function admissible ? why?
c) Does this heuristic leads to a monotonic f(n) ? why? Q. 3 a) Given two arbitrary admissible heuristics, h1 and h2, which composite
heuristic is better to use, min(h1, h2) or (h1 + h2) /2?
b) Iterative-Deepening search is usually preferred over Breadth-First search. Why?
c) A* search is usually preferred over Hill Climbing search. Why?
d) a) Let g(n) denote the path cost and d(n) denote the depth of a node n in a
search tree. Which kind of search is emulated by best-first search if the following
functions are used as heuristic functions?
i) h(n) = g(n)
ii) h(n) = d(n) ...

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