Topics:
- Assumptions in AI
- Problem Solving as Search
- Uninformed search
Problem Solving by Search
Problem formulation and solving
- Devise a representation scheme for states
- Describe an initial and a final state
- Describe operators
- Select which state to expand next
- Recognize the goal when generated
- Define state space, goal test, path cost, frontier of search
- Toy problems (8-puzzle, 8 queens, vacuum world, etc) vs real problems
(Traveling Salesman Problem (TSP), VLSI layout)
Search is a universal problem solving mechanism in AI. The sequence of steps
required to solve a problem is not known a priori and it must be determined by
a systematic exploration of alternatives.
Criteria for evaluating Search Strategies
- Completeness
- Optimality
- Time complexity
- Space complexity
Search Trees
General search methods: brute-force and informed. We focus on brute force today.
- breadth first search
- running time O(b^d)
- space requirements O(b^d)
- finds the minimum cost solution (shortest path to the goal)
- uniform cost search
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