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Journal of Computer Systems, Networks, and Communications
Volume 2010, Article ID 984059, 6 pages
Research Article

Subquery Allocation Problem and Heuristics for Secret Sharing Distributed Database System

Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University, Suita 565-0871, Japan

Received 17 August 2009; Revised 15 December 2009; Accepted 4 January 2010

Academic Editor: Abderrahim Benslimane

Copyright © 2010 Toshiyuki Miyamoto and Takeshi Ikemura. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We discuss query optimization in a secure distributed database system, called the Secret Sharing Distributed DataBase System (SSDDBS). We have to consider not only subquery allocations to distributed servers and data transfer on the network but also decoding distributed shared data. At first, we formulated the subquery allocation problem as a constraints satisfaction problem. Since the subquery allocation problem is NP-complete in general, it is not easy to obtain the optimal solution in practical time. Secondly, we proposed a heuristic evaluation function for the best-first search. We constructed an optimization model on an available optimization software, and evaluated the proposed method. The results showed that feasible solutions could be obtained by using the proposed method in practical time, and that quality of the obtained solutions was good.