Combinatorial optimization: algorithms and complexity
Combinatorial optimization: algorithms and complexity
Principles of database and knowledge-base systems, Vol. I
Principles of database and knowledge-base systems, Vol. I
Complexity of query processing in databases with OR-objects
PODS '89 Proceedings of the eighth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Indefinite and maybe information in relational databases
ACM Transactions on Database Systems (TODS)
Accommodating imprecision in database systems: issues and solutions
ACM SIGMOD Record - Directions for future database research & development
Answering heterogeneous database queries with degrees of uncertainty
Distributed and Parallel Databases
Update semantics of relational views
ACM Transactions on Database Systems (TODS)
A foundation of CODD's relational maybe-operations
ACM Transactions on Database Systems (TODS)
On semantic issues connected with incomplete information databases
ACM Transactions on Database Systems (TODS)
Extending the database relational model to capture more meaning
ACM Transactions on Database Systems (TODS)
Elements of the Theory of Computation
Elements of the Theory of Computation
Computers and Intractability: A Guide to the Theory of NP-Completeness
Computers and Intractability: A Guide to the Theory of NP-Completeness
Null values in data base management a denotational semantics approach
SIGMOD '79 Proceedings of the 1979 ACM SIGMOD international conference on Management of data
Incomplete information and dependencies in relational databases
SIGMOD '83 Proceedings of the 1983 ACM SIGMOD international conference on Management of data
IEEE Transactions on Knowledge and Data Engineering
A Generalized Relational Model for Indefinite and Maybe Information
IEEE Transactions on Knowledge and Data Engineering
Graph Theory With Applications
Graph Theory With Applications
Theory of Relational Databases
Theory of Relational Databases
Database research at NTHU and ITRI
ACM SIGMOD Record
An Exploration of Relationships Among Exclusive Disjunctive Data
IEEE Transactions on Knowledge and Data Engineering
Evaluating Aggregate Operations Over Imprecise Data
IEEE Transactions on Knowledge and Data Engineering
Integrating heterogeneous data warehouses using XML technologies
Journal of Information Science
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Imprecise data exist in databases due to their unavailability or to data/schema incompatibilities in a multidatabase system. Partial values have been used to represent imprecise data. Manipulation of partial values is therefore necessary to process queries involving imprecise data. In this article, we study the problem of eliminating redundant partial values that result from a projection on an attribute with partial values. The redundancy of partial values is defined through the interpretation of a set of partial values. This problem is equivalent to searching a minimal semantically-equivalent subset of a set of partial values. A semantically-equivalent subset contains exactly the same information as the original set. We derive a set of useful properties and apply a graph matching technique to develop an efficient algorithm for searching such a minimal subset and therefore eliminating redundant partial values. By this process, we not only provide a concise answer to the user, but also reduce the communication cost when partial values are requested to be transmitted from one site to another site in a distributed environment. Moreover, further manipulation of the partial values can be simplified. This work is also extended to the case of multi-attribute projections.