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March 19, 2005

Artificial Intelligence


In the early 1950s Herbert Simon, Allen Newell and Cliff Shaw conducted experiments in writing programs to imitate human thought processes. The experiments resulted in a program called Logic Theorist, which consisted of rules of already proved axioms. When a new logical expression was given to it, it would search through all possible operations to discover a proof of the new expression, using heuristics.
This was a major step in the development of AI. The Logic Theorist was capable of quickly solving thirty-eight out of fifty-two problems with proofs that Whitehead and Russel had devised. At the same time, Shanon came out with a paper on the possibility of computers playing chess. Though the works of Simon et al and Shanon demonstrated the concept of intelligent computer programs, the year 1956 is considered to be the start of the topic Artificial Intelligence. This is because the first AI conference, organised by John McCarthy, Marvin Minsky, Nathaniel Rochester and Claude Shanon at Dartmouth College in New Hampshire, was in 1956. This conference was the first organised effort in the field of machine intelligence. It was at that conference that John McCarthy, the developer of LISP programming language, proposed the term Artificial Intelligence. The Dartmouth conference paved the way for examining the use of computers to process symbols, the need for new languages and the role of computers for theorem proving instead of focusing on hardware that simulated intelligence.

Newell, Shaw and Simon developed a program called General Problem Solver (GPS) in 1959, that could solve many types of problems. It was capable of proving theorems, playing chess and solving complex puzzles. GPS introduced the concept of means-end analysis, involving the matching of present state and goal state. The difference between the two states was used to find out new search directions. GPS also introduced the concept of backtracking and subgoal states that improved the efficiency of problem solving .
Backtracking is used when the search drifts away from the goal state from a previous nearer state, to reach that state. The concept of subgoals introduced a goal-driven search through the knowledge. The major criticism of GPS was that it could not learn from previously solved problems. In the same year, John McCarthy developed LISP programming language, which became the most widely used AI programming language.

Artificial Intelligence and Expert Systems for Engineers
by C.S. Krishnamoorthy; S. Rajeev
CRC Press, CRC Press LLC
ISBN: 0849391253

Posted by Mehrdad at March 19, 2005 03:25 PM