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ACM Transactions on Database Systems (TODS), Volume 37 Issue 2, May 2012

Cardinal directions between complex regions
Markus Schneider, Tao Chen, Ganesh Viswanathan, Wenjie Yuan
Article No.: 8
DOI: 10.1145/2188349.2188350

Besides topological relationships and approximate relationships, cardinal directions like north and southwest have turned out to be an important class of qualitative spatial relationships. They are of interdisciplinary...

Certain conjunctive query answering in first-order logic
Jef Wijsen
Article No.: 9
DOI: 10.1145/2188349.2188351

Primary key violations provide a natural means for modeling uncertainty in the relational data model. A repair (or possible world) of a database is then obtained by selecting a maximal number of tuples without ever selecting two distinct tuples...

Comparing workflow specification languages: A matter of views
Serge Abiteboul, Pierre Bourhis, Victor Vianu
Article No.: 10
DOI: 10.1145/2188349.2188352

We address the problem of comparing the expressiveness of workflow specification formalisms using a notion of view of a workflow. Views allow to compare widely different workflow systems by mapping them to a common representation capturing...

Secure distributed computation of anonymized views of shared databases
Tamir Tassa, Ehud Gudes
Article No.: 11
DOI: 10.1145/2188349.2188353

We consider the problem of computing efficient anonymizations of partitioned databases. Given a database that is partitioned between several sites, either horizontally or vertically, we devise secure distributed algorithms that allow the different...

Exact and approximate algorithms for the most connected vertex problem
Cheng Sheng, Yufei Tao, Jianzhong Li
Article No.: 12
DOI: 10.1145/2188349.2188354

An (edge) hidden graph is a graph whose edges are notexplicitly given. Detecting the presence of an edge requires an expensive edge probing query. We consider the k Most Connected Vertex (k-MCV) problem on hidden bipartite...

The implication problem of data dependencies over SQL table definitions: Axiomatic, algorithmic and logical characterizations
Sven Hartmann, Sebastian Link
Article No.: 13
DOI: 10.1145/2188349.2188355

We investigate the implication problem for classes of data dependencies over SQL table definitions. Under Zaniolo's “no information” interpretation of null markers we establish an axiomatization and algorithms to decide the implication...

Stochastic skylines
Wenjie Zhang, Xuemin Lin, Ying Zhang, Muhammad Aamir Cheema, Qing Zhang
Article No.: 14
DOI: 10.1145/2188349.2188356

In many applications involving multiple criteria optimal decision making, users may often want to make a personal trade-off among all optimal solutions for selecting one object that fits best their personal needs. As a key feature, the skyline in...

Online subspace skyline query processing using the compressed skycube
Tian Xia, Donghui Zhang, Zheng Fang, Cindy Chen, Jie Wang
Article No.: 15
DOI: 10.1145/2188349.2188357

The skyline query can help identify the “best” objects in a multi-attribute dataset. During the past decade, this query has received considerable attention in the database research community. Most research focused on computing the...