Implementing imprecision in information systems
Information Sciences: an International Journal - Special issue on expert systems
ACM Transactions on Database Systems (TODS)
Fuzzy querying with SQL: extensions and implementation aspects
Fuzzy Sets and Systems - Mathematical Modelling
A guide to the SQL standard (2nd ed.)
A guide to the SQL standard (2nd ed.)
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
Performing database operations over mismatched domains
Performing database operations over mismatched domains
Aggregates in possibilistic databases
VLDB '89 Proceedings of the 15th international conference on Very large data bases
Accommodating imprecision in database systems: issues and solutions
ACM SIGMOD Record - Directions for future database research & development
Evaluating aggregates in possibilistic relational databases
Data & Knowledge Engineering
Answering heterogeneous database queries with degrees of uncertainty
Distributed and Parallel Databases
Refining imprecise data by integrity constraints
Data & Knowledge Engineering
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)
Computers and Intractability: A Guide to the Theory of NP-Completeness
Computers and Intractability: A Guide to the Theory of NP-Completeness
Searching a minimal semantically-equivalent subset of a set of partial values
The VLDB Journal — The International Journal on Very Large Data Bases
IEEE Transactions on Knowledge and Data Engineering
The Management of Probabilistic Data
IEEE Transactions on Knowledge and Data Engineering
Relational Databases with Exclusive Disjunctions
Proceedings of the Eighth International Conference on Data Engineering
The Theory of Probabilistic Databases
VLDB '87 Proceedings of the 13th International Conference on Very Large Data Bases
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
Aggregation of Imprecise and Uncertain Information in Databases
IEEE Transactions on Knowledge and Data Engineering
Generalized Normal Forms for Probabilistic Relational Data
IEEE Transactions on Knowledge and Data Engineering
Temporal Probabilistic Concepts from Heterogeneous Data Sequences
Soft-Ware 2002 Proceedings of the First International Conference on Computing in an Imperfect World
A Decathlon in Multidimensional Modeling: Open Issues and Some Solutions
DaWaK 2000 Proceedings of the 4th International Conference on Data Warehousing and Knowledge Discovery
Scalar aggregation in inconsistent databases
Theoretical Computer Science - Database theory
Database aggregation of imprecise and uncertain evidence
Information Sciences—Informatics and Computer Science: An International Journal - special issue: Knowledge discovery from distributed information sources
Integrating heterogeneous data warehouses using XML technologies
Journal of Information Science
OLAP over uncertain and imprecise data
VLDB '05 Proceedings of the 31st international conference on Very large data bases
Learning accurate and concise naïve Bayes classifiers from attribute value taxonomies and data
Knowledge and Information Systems
OLAP over uncertain and imprecise data
The VLDB Journal — The International Journal on Very Large Data Bases
Efficient aggregation algorithms for probabilistic data
SODA '07 Proceedings of the eighteenth annual ACM-SIAM symposium on Discrete algorithms
Estimating and bounding aggregations in databases with referential integrity errors
Proceedings of the ACM 11th international workshop on Data warehousing and OLAP
Extended aggregations for databases with referential integrity issues
Data & Knowledge Engineering
ADBIS'10 Proceedings of the 14th east European conference on Advances in databases and information systems
ALT'05 Proceedings of the 16th international conference on Algorithmic Learning Theory
Aggregate queries on probabilistic record linkages
Proceedings of the 15th International Conference on Extending Database Technology
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Imprecise data in databases were originally denoted as null values, which represent the meaning of "values unknown at present." More generally, a partial value corresponds to a finite set of possible values for an attribute in which exactly one of the values is the "true" value. In this paper, we define a set of extended aggregate operations, namely sum, average, count, maximum, and minimum, which can be applied to an attribute containing partial values. Two types of aggregate operators are considered: scalar aggregates and aggregate functions. We study the properties of the aggregate operations and develop efficient algorithms for count, maximum and minimum. However, for sum and average, we point out that in general it takes exponential time complexity to do the computations.