Introduction to expert systems
Introduction to expert systems
Principles of database and knowledge-base systems, Vol. I
Principles of database and knowledge-base systems, Vol. I
A closed-form evaluation for Datalog queries with integer (gap)-order constraints
ICDT Selected papers of the 4th international conference on Database theory
Selected papers of the 9th annual ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Principles of database query processing for advanced applications
Principles of database query processing for advanced applications
Thinksheet: a tool for tailoring complex documents
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
Thinksheet: a tool for information navigation
Thinksheet: a tool for information navigation
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We pose a query problem about the behavior of a consultation system S: given a constraint formula q and a potential conclusion c for S, determine if there is a user input binding that satisfies q and causes S to conclude c. Existing rule-based expert systems, both forward and backward chaining[3], implement a consultation mechanism S, but are not designed for these queries about S. For general production systems, the queries are undecidable. Here we solve the problem for useful sublanguages of acyclic production systems.We implement a query tool in a Datalog + constraints framework, and optimize for “embedded decision trees” in the rule system. Our data complexity is &THgr;(n·ƒ(n)) in the size of the embedded trees, versus &THgr;(n·ƒ(n) + n2) for existing datalog evaluation algorithms, where ƒ(n) is the cost of destructively conjoining a constraint of unit size into a conjunction of n constraints.