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VimalEA C461- Artificial Intelligence. To discuss
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1. S.P.Vimal
http://discovery.bits-pilani.ac.in/~vimalsp/1910AI/ EA C461 – Artificial IntelligenceUninformed Search Strategies
2. Vimal EA C461- Artificial Intelligence To discuss… Best First Search
Greedy Best First Search
A* Search
Heuristics, Design Issues
Memory Bounded Search
3. Vimal EA C461- Artificial Intelligence Introduction Search
Heuristic / Informed
Uses additional information about nodes (heuristics) that have not yet been explored to decide which nodes to examine next
Blind / Uninformed
Assumes no additional information about the problem
Heuristic function h (n) used in search provides an estimate of the distance from any given node to a goal node
4. Vimal EA C461- Artificial Intelligence Best First Search A node is selected for expansion based on an evaluation function f(n)
Choose the node which appears to be best while expanding
Best First Search algorithms differs in the evaluation function
Evaluation function incorporate the problem specific knowledge in the form of h(n)
h(n) ? heuristic function , a component of f(n)
? Estimated cost of cheapest path to the goal node
h(n) = 0, if n is the goal node
Greedy Best First Search, A* Search
5. Vimal EA C461- Artificial Intelligence Greedy best-first search Expands the node that is closest to the goal
Consider route finding problem in Romania
Use of hSLD, Straight Line Distance Heuristic
Evaluation function f(n) = h(n) (heuristic), estimate of cost from n to goal
For the problem of finding route from Arad to Burcharest…
6. Vimal EA C461- Artificial Intelligence