Jens Christensen

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Jens Christensen, an American computer scientist, AI-researcher and entrepreneur, Ph.D. from Stanford University in 1991 on automatic abstraction in planning. Along with Richard Korf, he elaborated on a Unified Theory of Heuristic Evaluation functions and Its Applications to Learning on optimization of feature weights by hill climbing methods and linear regression. In one experiment, a set of relative weights for different chess pieces was automatically learned.

=Experiments with Chess= Excerpt from A Unified Theory of Heuristic Evaluation functions and Its Applications to Learning. : As a serious test, we chose the game of chess and a simple evaluation function consisting only of material advantage. The experiment was to see if the learning program would approximate the classically accepted weights for the pieces: 9 for the queen, 5 for the rook, 3 for the bishop, 3 for the knight, and 1 for the pawn.

The chess program was implemented using a two-ply mini-max search with alpha-beta pruning and quiescence. 1400 half moves were made between each regression. If neither side won during a game it was stopped after 100 half-moves and a new game was started. For purposes of the experiment, a win was assigned one more than the total initial material value, and the individual piece values were rounded off to the nearest 0.5. The pieces stabilized at: Queen, 8.0; rook, 4.0; bishop, 4.0; knight, 3.0; pawn 2.0. ...

=Selected Publications=
 * Jens Christensen, Richard Korf (1986). A Unified Theory of Heuristic Evaluation functions and Its Applications to Learning. AAAI-86, pdf
 * Jens Christensen (1986). Learning Static Evaluation Functions by Linear Regression. in Tom Mitchell, Jaime Carbonell, Ryszard Michalski (1986). Machine Learning: A Guide to Current Research. The Kluwer International Series in Engineering and Computer Science, Vol. 12
 * Jens Christensen (1990). A Hierarchical Planner that Generates Its Own Hierarchies. AAAI-90, pdf
 * Jens Christensen, Adam Grove (1991). A Formal Model Classical Planning. IJCAI 91, pdf
 * Jens Christensen (1991). Automatic Abstraction in Planning. Ph.D. thesis, Stanford University, pdf

=External Links=
 * Jens Christensen | LinkedIn
 * Jens Christensen: The Innovation Interview | Brulte & Company, September 8, 2014

=References= Up one level