Man Lung, Yiu Yufei, Tao Nikos Mamoulis, Y. Tao, N. Mamoulis
Abstract Existing spatiotemporal indexes suffer from either large update cost or poor query performance, except for the B x-tree (the state-of-the-art), which consists of multiple B +-trees indexing...
© 2001 Springer-Verlag New York Inc. Constraint-Based Processing of Multiway Spatial Joins 1 (2007)
D. Papadias, N. Mamoulis, Y. Theodoridis
Abstract. A multiway spatial join combines information found in three or more spatial relations with respect to some spatial predicates. Motivated by their close correspondence with constraint...
E#cient Image Retrieval by Exploiting Vertical Fragmentation (2007)
N. Mamoulis, N. J. Nes, M. L. Kersten, Nikos Mamoulis, ...
Efficient image retrieval by exploiting vertical fragmentation
Reverse Nearest Neighbors Search in Ad Hoc Subspaces (2007)
Given an object q, modeled by a multidimensional point, a reverse nearest neighbors (RNN) query returns the set of objects in the database that have q as their nearest neighbor. In this paper, we...
Discovery of Periodic Patterns in Spatiotemporal Sequences (2007)
Cao, HP, Mamoulis, N, Cheung, DW
In many applications that track and analyze spatiotemporal data, movements obey periodic patterns; the objects follow the same routes (approximately) over regular time intervals. For example, people...
Ad-hoc distributed spatial joins on mobile devices (2006)
Kalnis, P, Mamoulis, N, Bakiras, S, Li, X
PDAs, cellular phones and other mobile devices are now capable of supporting complex data manipulation operations. Here, we focus on ad-hoc spatial joins of datasets residing in multiple...
Detecting the Direction of Motion in a Binary Sensor Network (2006)
We examine the problem of detecting the direction of motion in a binary sensor network; in such a network each sensor’s value is supplied reliably in a single bit of information: whether the moving...
Reverse nearest neighbors in large graphs (2006)
Yiu, ML, Papadias, D, Mamoulis, N, Tao, Y
A reverse nearest neighbor (RNN) query returns the data objects that have a query point as their nearest neighbor (NN). Although such queries have been studied quite extensively in Euclidean spaces,...
Aggregate nearest neighbor queries in road networks (2005)
Yiu, ML, Mamoulis, N, Papadias, D
Aggregate nearest neighbor queries return the object that minimizes an aggregate distance function with respect to a set of query points. Consider, for example, several users at specific locations...
Iterative projected clustering by subspace mining (2005)
Irrelevant attributes add noise to high-dimensional clusters and render traditional clustering techniques inappropriate. Recently, several algorithms that discover projected clusters and their...
Mining frequent spatio-temporal sequential patterns (2005)
Cao, HP, Mamoulis, N, Cheung, DWL
Many applications track the movement of mobile objects, which can be represented as sequences of timestamped locations. Given such a spatiotemporal series, we study the problem of discovering...
First Look at Average-Case Complexity for Planar Maximum-Likelihood Detection (2005)
In this paper, an efficient exact maximum-likelihood (ML) detection scheme is presented for a multiple-input single-output ISO) system with real signal constellations. The pro-posed technique has a...
Indexing useful structural patterns for XML query processing (2005)
Lian, W, Mamoulis, N, Cheung, DWL, Yiu, SM
Queries on semistructured data are hard to process due to the complex nature of the data and call for specialized techniques. Existing path-based indexes and query processing algorithms are not...
Tao, Y, Zhang, J, Papadias, D, Mamoulis, N
Existing models for nearest neighbor search in multidimensional spaces are not appropriate for query optimization because they either lead to erroneous estimation or involve complex equations that...
An efficient and scalable algorithm for clustering XML documents by structure (2004)
Wang, L, Cheung, DWL, Mamoulis, N, Yiu, SM
With the standardization of XML as an information exchange language over the Internet, a huge amount of information is formatted in XML documents. In order to analyze this information efficiently,...
All-nearest-neighbors queries in spatial databases (2004)
Zhang, J, Mamoulis, N, Papadias, D, Tao, Y
Given two sets A and B of multidimensional objects, the all-nearest-neighbors (ANN) query retrieves for each object in A its nearest neighbor in B. Although this operation is common in several...
Slot index spatial join (2003)
Efficient processing of spatial joins is very important due to their high cost and frequent application in spatial databases and other areas involving multidimensional data. This paper proposes slot...
Frequent-pattern based iterative projected clustering (2003)
Irrelevant attributes add noise to high dimensional clusters and make traditional clustering techniques inappropriate. Projected clustering algorithms have been proposed to find the clusters in...
Indexing and Retrieval of Historical Aggregate Information about Moving Objects (2002)
Papadias, D, Tao, Y, Zhang, J, Mamoulis, N, Shen, Q, Sun, J
Spatio-temporal databases store information about the positions of individual objects over time. In many applications however, such as traffic supervision or mobile communication systems, only...
A survey on multidimensional access methods (2001)
The extraordinary format of spatial data and the fact that there is no straightforward mapping of spatial objects from the multidimensional space to the 1-dimensional space, stimulated various...