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Artificial Intelligence. Tarik Booker. What we will cover…. History Artificial Intelligence as Representation and Search Languages used in Artificial Intelligence Applications. History of Artificial Intelligence. Derives from Logic Aristotle Charles Babbage George Boole Alan Turing
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Artificial Intelligence Tarik Booker
What we will cover… • History • Artificial Intelligence as Representation and Search • Languages used in Artificial Intelligence • Applications
History of Artificial Intelligence • Derives from Logic • Aristotle • Charles Babbage • George Boole • Alan Turing • Turing Test
AI as Representation and Search • Predicate Calculus • State Space • Heuristic Search
Predicate Calculus • Covered later in presentation (Logic Programming) • Basics: • Proposition – statement that may or may not be true
State Space • The structure of the state that you are in • A four-tuple [N, A, S, GD] • Where: • N is the set of nodes (or states) of the graph • A is the set of arcs (links) between nodes • S, a non-empty subset of N, contains the start state(s) of the problem • GD, a non-empty subset of N contains the goal state(s) of the problem • A solution path is a path through this graph from a node S to a node in GD
Heuristics • (From Greek “eurisco” meaning “to discover”) • A strategy for selectively searching a problem space • Searches along lines that have a high probability of success • Not guaranteed to find correct solution
Why use Heuristics? • Problem may not have an exact solution because of ambiguities • Ex: Medical Diagnosis • Problem may have exact solution, but the computational cost of finding it may be prohibitive • Ex: Chess • Heuristics are at the core of AI.
Heuristic Algorithms • Heuristic Measure • Best-first Search • Tic-Tac Toe (on board)
Heuristics Terms • Admissibility • Heuristics that find the shortest path to a goal whenever it exists are said to be admissible • Informedness • Are any heuristics better that the one we are using? • Monotonicity • When a state is discovered using heuristic search, is there a guarantee that the same state won’t be reached with a cheaper cost?
Languages Used in AI • LISP • PROLOG
Applications of AI • Game Playing • Heuristics • Automated Reasoning and Theorem Proving • Expert Systems • Natural Language Understanding • Planning and Robotics • Machine Learning
Sources Luger, George F. Stubblefield, William A. Artificial Intelligence (3rd Edition)