Constraint Satisfaction with Probabilistic Preferences on Variable Values Constraint Satisfaction with Probabilistic Preferences on Variable Values
نویسندگان
چکیده
Crossword puzzle solving is a classic constraint satisfaction problem, but, when solving a real puzzle, the mapping from clues to variable domains is not perfectly crisp. At best, clues induce a probability distribution over viable targets, which must somehow be respected along with the constraints of the puzzle. Motivated by this type of problem, we provide a formal model of constraint satisfaction with probabilistic preferences on variable values. Two natural optimization problems are deened for this model: maximizing the probability of a correct solution, and maximizing the number of correct words (variable values) in the solution. We provide an eecient iterative approximation for the latter based on dynamic programming and present very encouraging results on a collection of real and artiicial crossword puzzles.
منابع مشابه
Solving Crossword Puzzles as Probabilistic Constraint Satisfaction
Crossword puzzle solving is a classic constraint satisfaction problem, but, when solving a real puzzle, the mapping from clues to variable domains is not perfectly crisp. At best, clues induce a probability distribution over viable targets, which must somehow be respected along with the constraints of the puzzle. Motivated by this type of problem, we describe a formal model of constraint satisf...
متن کاملUsing Expectation Maximization to Find Likely Assignments for Solving Constraint Satisfaction Problems
We present a new probabilistic framework for finding likely variable assignments in difficult constraint satisfaction problems. Finding such assignments is key to efficient search, but practical efforts have largely been limited to random guessing and heuristically designed weighting systems. In contrast, we derive a new version of Belief Propagation (BP) using the method of Expectation Maximiz...
متن کاملVariable and Value Ordering Heuristics for Hard Constraint Satisfaction Problems: an Application to Job Shop Scheduling
Hard Constraint Satisfaction Problems (HCSPs) are Constraint Satisfaction Problems (CSPs) with very large search spaces and very few solutions. Real-life problems such as design or factory scheduling are examples of HCSPs. These problems typically involve several hundred (or even several thousand) variables, each with up to several hundred possible values, only a very tiny fraction of which ult...
متن کاملPreference Propagation in Temporal/Capacity Constraint Graphs
Scheduling can be formalized as a constraint satisfaction problem (CSP). Within this framework activities in a plan are interconnected via temporal relation constraints a la Allen, thereby defining a temporal constraint graph (TCG). Additionally there are capacity constraints restricting the use of each resource to only one activity at a time. Together these constraints form a temporallcapacity...
متن کاملAn Examination of Probabilistic Value-Ordering Heuristics
Searching for solutions to constraint satisfaction problems (CSPs) is NP-hard in general. Heuristics for variable and value ordering have proven useful in guiding the search towards more fruitful areas of the search space and hence reducing the amount of time spent searching for solutions. Static ordering methods impart an ordering in advance of the search and dynamic ordering methods use infor...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 1999