Exploiting the Deep Structure of Constraint Problems

 AUTHOR = "Colin P. Williams and Tad Hogg",
 TITLE = "Exploiting the Deep Structure of Constraint Problems",
 JOURNAL = "Artificial Intelligence",
 VOLUME = "70",
 PAGES = "73-117",
 YEAR = "1994"}


We introduce a technique for analyzing the behavior of sophisticated A.I. search programs working on realistic, large-scale problems. This approach allows us to predict where, in a space of problem instances, the hardest problems are to be found and where the fluctuations in difficulty are greatest. Our key insight is to shift emphasis from modelling sophisticated algorithms directly to modelling a search space that captures their principal effects. We compare our model's predictions with actual data on real problems obtained independently and show that the agreement is quite good. By systematically relaxing our underlying modelling assumptions we identify their relative contribution to the remaining error and then remedy it. We also discuss further applications of our model and suggest how this type of analysis can be generalized to other kinds of A.I. problems.
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