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2008 IEEE 24th International Conference on Data Engineering (2008)
Cancun, Mexico
Apr. 7, 2008 to Apr. 12, 2008
ISBN: 978-1-4244-1836-7
pp: 1454-1456
Yunjun Gao , College of Computer Science, Zhejiang University, Hangzhou 310027, P. R. China. gaoyj@zju.edu.cn
Jing Zhang , College of Computer Science, Zhejiang University, Hangzhou 310027, P. R. China. zhangj@zju.edu.cn
Gencai Chen , College of Computer Science, Zhejiang University, Hangzhou 310027, P. R. China. chengc@zju.edu.cn
Qing Li , Department of Computer Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, P. R. China. itqli@cityu.edu.hk
Shen Liu , College of Computer Science, Zhejiang University, Hangzhou 310027, P. R. China. lius@zju.edu.cn
Chun Chen , College of Computer Science, Zhejiang University, Hangzhou 310027, P. R. China. chenc@zju.edu.cn
ABSTRACT
Given two sets D<inf>A</inf> and D<inf>B</inf> of multidimensional objects, a spatial region R, and a critical distance d<inf>c</inf>, an optimal-nearest-neighbor (ONN) query retrieves outside R, the object in D<inf>B</inf> with maximum optimality. Let CAR (S<inf>p</inf>, p) be the cardinality of the subset S<inf>p</inf> of objects in D<inf>A</inf> which locate within R and are enclosed by the vicinity circle centered at p with radius d<inf>c</inf>. Then, an object o is said to be better than another one o' if (i) CAR (S<inf>o</inf>, o) ≫ CAR (S<inf>o'</inf>, o'), or (ii) when CAR (S<inf>o</inf>, o) = CAR (S<inf>o'</inf>, o') the sum of the weighted distance from each object in S<inf>o</inf> to o is smaller than the sum of the weighted distance between every object in S<inf>o'</inf> and o'. This type of queries is quite useful in many decision making applications. In this paper, we formalize the ONN query, develop the optimality metric, and propose several algorithms for finding optimal nearest neighbors efficiently. Our techniques assume that both D<inf>A</inf> and D<inf>B</inf> are indexed by R-trees. Extensive experiments demonstrate the efficiency and scalability of our proposed algorithms using both real and synthetic datasets.
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CITATION

Y. Gao, G. Chen, J. Zhang, S. Liu, Q. Li and C. Chen, "Optimal-Nearest-Neighbor Queries," 2008 IEEE 24th International Conference on Data Engineering(ICDE), Cancun, Mexico, 2008, pp. 1454-1456.
doi:10.1109/ICDE.2008.4497587
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