Scalable Probabilistic Similarity Ranking in Uncertain Databases (Technical Report) (2009)
Bernecker, Thomas, Kriegel, Hans-Peter, Mamoulis, Nikos, Renz, Matthias, Zuefle, Andreas
This paper introduces a scalable approach for probabilistic top-k similarity ranking on uncertain vector data. Each uncertain object is represented by a set of vector instances that are assumed to be...
Anonymity in Unstructured Data (2009)
Manolis Terrovitis, Nikos Mamoulis, Panos Kalnis
In this paper we study the problem of protecting privacy in the publication of set-valued data. Con-sider a collection of transactional data that contains detailed information about items bought...
TR-2008-03 Continuous Spatial Assignment of Moving Users (2009)
Leong Hou U, Kyriakos Mouratidis, Nikos Mamoulis
Consider a large set of wireless access points owned by a company, which are scattered in a city. Each access point has a coverage region (i.e., an area it can transmit/receive data in) and a...
Man Lung Yiu, Nikos Mamoulis, Xiangyuan Dai, Yufei Tao, Michail Vaitis
Abstract—We study the problem of answering spatial queries in databases where objects exist with some uncertainty and they are associated with an existential probability. The goal of a thresholding...
Common Influence Join: A Natural Join Operation for Spatial Pointsets (2008)
Man Lung Yiu, Nikos Mamoulis, Panagiotis Karras
Abstract — We identify and formalize a novel join operator for two spatial pointsets P and Q. The common influence join (CIJ) returns the pairs of points (p, q), p ∈ P, q ∈ Q, such that there...
Lattice Histograms: a Resilient Synopsis Structure (2008)
Panagiotis Karras, Nikos Mamoulis
Abstract — Despite the surge of interest in data reduction techniques over the past years, no method has been proposed to date that can always achieve approximation quality preferable to that of...
We study the continuous evaluation of spatial join queries and extensions thereof, defined by interesting combinations of sensor readings (events) that co-occur in a spatial neighborhood. An example...
Reverse Nearest Neighbor Search in Metric Spaces (2008)
Yufei Tao, Man Lung Yiu, Nikos Mamoulis
Abstract—Given a set D of objects, a reverse nearest neighbor (RNN) query returns the objects o in D such that o is closer to a query object q than to any other object in D, according to a certain...
Reverse Nearest Neighbors in Large Graphs (2008)
Man Lung Yiu, Dimitris Papadias, Nikos Mamoulis, Yufei Tao
Abstract—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...
Efficient quantile retrieval on multi-dimensional data (2008)
Man Lung Yiu, Nikos Mamoulis, Yufei Tao
Abstract. Given a set of N multi-dimensional points, we study the computation of φ-quantiles according to a ranking function F, which is provided by the user at runtime. Specifically, F computes a...
Man Lung Yiu, Spiridon Bakiras, Nikos Mamoulis
We study the continuous evaluation of spatial join queries and extensions thereof, defined by interesting combinations of sensor readings (events) that co-occur in a spatial neighborhood. An example...
Research Track Paper ABSTRACT Fast Mining of Spatial (2008)
Xin Zhang, Nikos Mamoulis, David W. Cheung, Yutao Shou
Spatial collocation patterns associate the co-existence of nonspatial features in a spatial neighborhood. An example of such a pattern can associate contaminated water reservoirs with certain...
Ad-hoc Distributed Spatial Joins on Mobile Devices (2008)
Panos Kalnis, Nikos Mamoulis, Spiridon Bakiras, Xiaochen Li
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...
We study the continuous evaluation of spatial join queries and extensions thereof, defined by interesting combinations of sensor readings (events) that co-occur in a spatial neighborhood. An example...
ABSTRACT Integration of Spatial Join Algorithms for Processing Multiple Inputs (2008)
Several techniques that compute the join between two spatial datasets have been proposed during the last decade. Among these methods, some consider existing indices for the joined inputs, while...
Reverse Nearest Neighbor Search in Metric Spaces (2008)
Yufei Tao, Man Lung Yiu, Nikos Mamoulis
Abstract—Given a set D of objects, a reverse nearest neighbor (RNN) query returns the objects o in D such that o is closer to a query object q than to any other object in D, according to a certain...
Dimitris Papadias, Yufei Tao, Jun Zhang, Nikos Mamoulis, Qiongmao Shen, Jimeng Sun, ...
VLDB Conference......................................................................� � � ÓÚ�Ö
Abstract Efficient Processing of Joins on Set-valued Attributes (2008)
Object-oriented and object-relational DBMS support setvalued attributes, which are a natural and concise way to model complex information. However, there has been limited research to-date on the...
The citiKey website. http://www.e-street.com (2008)
Huiping Cao, Nikos Mamoulis, David W. Cheung
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...
The citiKey website. http://www.e-street.com (2008)
Huiping Cao, Nikos Mamoulis, David W. Cheung, Ieee Computer Society
Abstract—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...
Efficient Top-k Aggregation of Ranked Inputs (2008)
Nikos Mamoulis, Man Lung Yiu, Kit Hung Cheng, David W. Cheung
A top-k query combines different rankings of the same set of objects and returns the k objects with the highest combined score according to an aggregate function. We bring to light some key...
Efficient quantile retrieval on multi-dimensional data (2008)
Man Lung Yiu, Nikos Mamoulis, Yufei Tao
Abstract. Given a set of N multi-dimensional points, we study the computation of φ-quantiles according to a ranking function F, which is provided by the user at runtime. Specifically, F computes a...
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...
Reverse Nearest Neighbors in Large Graphs (2008)
Man Lung Yiu, Dimitris Papadias, Nikos Mamoulis, Yufei Tao
Abstract—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...
ABSTRACT Fast Mining of Spatial (2008)
Xin Zhang, Nikos Mamoulis, David W. Cheung, Yutao Shou
Spatial collocation patterns associate the co-existence of nonspatial features in a spatial neighborhood. An example of such a pattern can associate contaminated water reservoirs with certain...
Discovering Minimal Infrequent Structures from XML Documents (2008)
Wang Lian, Nikos Mamoulis, David W. Cheung, S. M. Yiu
Abstract. More and more data (documents) are wrapped in XML format. Mining these documents involves mining the corresponding XML structures. However, the semi-structured (tree structured) XML makes...
Indexing Useful Structural Patterns for XML Query Processing (2008)
Wang Lian, Nikos Mamoulis, Ieee Computer Society, S. M. Yiu
Abstract—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...
Reverse Nearest Neighbors in Large Graphs (2008)
A reverse nearest neighbor query returns the data objects that have a query point as their nearest neighbor. Although such queries have been studied quite extensively in Euclidean spaces, there is no...
ABSTRACT Mining, Indexing, and Querying Historical Spatiotemporal Data (2008)
Nikos Mamoulis, Marios Hadjieleftheriou
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...
ABSTRACT Integration of Spatial Join Algorithms for Processing Multiple Inputs (2007)
Several techniques that compute the join between two spatial datasets have been proposed during the last decade. Among these methods, some consider existing indices for the joined inputs, while...
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
Dimitris Papadias, Nikos Mamoulis, Vasilis Delis
This paper proposes a framework for the handling of spatio-temporal queries with inexact matches, using the concept of relation similarity. We initially describe a binary string encoding for 1D...
Nikos Mamoulis, Dimitris Papadias
Due to the evolution of Geographical Information Systems, large collections of spatial data having various thematic contents are currently available. As a result, the interest of users is not limited...
Continuous Constraint Query Evaluation for Spatiotemporal Streams (2007)
Marios Hadjieleftheriou, Nikos Mamoulis, Yufei Tao
Abstract. In this paper we study the evaluation of continuous constraint queries (CCQs) for spatiotemporal streams. A CCQ triggers an alert whenever a configuration of constraints between streaming...
Continuous Constraint Query Evaluation for Spatiotemporal Streams (2007)
Marios Hadjieleftheriou, Nikos Mamoulis, Yufei Tao
Abstract. In this paper we study the evaluation of continuous constraint queries (CCQs) for spatiotemporal streams. A CCQ triggers an alert whenever a configuration of constraints between streaming...
Continuous Constraint Query Evaluation for Spatiotemporal Streams (2007)
Marios Hadjieleftheriou, Nikos Mamoulis, Yufei Tao
Abstract. In this paper we study the evaluation of continuous constraint queries (CCQs) for spatiotemporal streams. A CCQ triggers an alert whenever a configuration of constraints between streaming...
Fast Data Anonymization with Low Information Loss (2007)
Gabriel Ghinita, Panagiotis Karras, Panos Kalnis, Nikos Mamoulis
Recent research studied the problem of publishing microdata without revealing sensitive information, leading to the privacy preserving paradigms of k-anonymity and ℓ-diversity. k-anonymity protects...
Evaluation of spatial pattern queries in sensor networks (2007)
Man Lung Yiu, Nikos Mamoulis, Spiridon Bakiras
We study the continuous evaluation of spatial join queries and extensions thereof, defined by interesting combinations of sensor readings (events) that co-occur in a spatial neighbor-hood. An example...
Continuous Monitoring of Exclusive Closest Pairs (2007)
Leong Hou U, Nikos Mamoulis, Man Lung Yiu
Given two datasets A and B, their exclusive closest pairs (ECP) join is a one-to-one assignment of objects from the two datasets, such that (i) the closest pair (a, b) in A ×B is in the result and...
Fast Data Anonymization with Low Information Loss (2007)
Gabriel Ghinita, Panagiotis Karras, Panos Kalnis, Nikos Mamoulis
Recent research studied the problem of publishing microdata without revealing sensitive information, leading to the privacy preserving paradigms of k-anonymity and ℓ-diversity. k-anonymity protects...
Continuous nearest neighbor monitoring in road networks (2006)
Mouratidis, Kyriakos, Yiu, Man Lung, Papadias, Dimitris, Mamoulis, Nikos
Recent research has focused on continuous monitoring of nearest neighbors (NN) in highly dynamic scenarios, where the queries and the data objects move frequently and arbitrarily. All existing...
Efficient aggregation of ranked inputs (2006)
Nikos Mamoulis, Kit Hung Cheng, Man Lung Yiu, David W. Cheung
A top-k query combines different rankings of the same set of objects and returns the k objects with the highest combined score according to an aggregate function. We bring to light some key...
Aggregate nearest neighbor queries in road networks (2005)
Yiu, Man Lung, Mamoulis, Nikos, Papadias, Dimitris
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...
RPJ: producing fast join results on streams through rate-based optimization (2005)
Tao, Yufei, Yiu, Man Lung, Papadias, Dimitris, Hadjieleftheriou, Marios, Mamoulis, Nikos
We consider the problem of 'progressively' joining relations whose records are continuously retrieved from remote sources through an unstable network that may incur temporary failures. The objectives...
Reverse nearest neighbors in large graphs (2005)
Yiu, Man Lung, Papadias, Dimitris, Mamoulis, Nikos, Tao, Yufei
A reverse nearest neighbor query returns the data objects that have a query point as their nearest neighbor. Although such queries have been studied quite extensively in Euclidean spaces, there is no...
Mining frequent spatio-temporal sequential patterns (2005)
Huiping Cao, Nikos Mamoulis, David W. Cheung
Many applications track the movement of mobile objects, which can be represented as sequences of timestamped locations. Given such a spatio-temporal series, we study the problem of discovering...
On discovering moving clusters in spatio-temporal data (2005)
Panos Kalnis, Nikos Mamoulis, Spiridon Bakiras
Abstract. A moving cluster is defined by a set of objects that move close to each other for a long time interval. Real-life examples are a group of migrating animals, a convoy of cars moving in a...
Probabilistic Spatial Queries on Existentially Uncertain Data (2005)
Xiangyuan Dai, Man Lung Yiu, Nikos Mamoulis, Michail Vaitis
Abstract. We study the problem of answering spatial queries in databases where objects exist with some uncertainty and they are associated with an existential probability. The goal of a thresholding...
Aggregate nearest neighbor queries in road networks (2005)
Man Lung Yiu, Nikos Mamoulis, Dimitris Papadias
Abstract—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...
Iterative Projected Clustering by Subspace Mining (2005)
Abstract—Irrelevant attributes add noise to high-dimensional clusters and render traditional clustering techniques inappropriate. Recently, several algorithms that discover projected clusters and...
Fast and exact warping of time series using adaptive segmental approximations (2005)
Nikos Mamoulis, David W. Cheung, Eamonn Keogh
Abstract. Similarity search is a core module of many data analysis tasks, including search by example, classification, and clustering. For time series data, Dynamic Time Warping (DTW) has been proven...
Evaluation of top-k OLAP queries using aggregate R-trees (2005)
Nikos Mamoulis, Spiridon Bakiras, Panos Kalnis
Abstract. A top-k OLAP query groups measures with respect to some abstraction level of interesting dimensions and selects the k groups with the highest aggregate value. An example of such a query is...
One-Pass Wavelet Synopses for Maximum-Error Metrics (2005)
Panagiotis Karras, Nikos Mamoulis
We study the problem of computing waveletbased synopses for massive data sets in static and streaming environments. A compact representation of a data set is obtained after a thresholding process is...
Fast and exact warping of time series using adaptive segmental approximations (2005)
Yutao Shou, Yutao Shou, Nikos Mamoulis, Nikos Mamoulis, Nikos Mamoulis, David W. Cheung, ...
Abstract Similarity search is a core module of many data analysis tasks, including search by example, classification, and clustering. Dynamic Time Warping (DTW) has been used to calculate a robust...
Aggregate nearest neighbor queries in road networks (2005)
Man Lung Yiu, Nikos Mamoulis, Dimitris Papadias
Abstract—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...
Probabilistic Spatial Queries on Existentially Uncertain Data (2005)
Xiangyuan Dai, Man Lung Yiu, Nikos Mamoulis, Yufei Tao, Michail Vaitis
Abstract. We study the problem of answering spatial queries in databases where objects exist with some uncertainty and they are associated with an existential probability. The goal of a thresholding...
Iterative Projected Clustering by Subspace Mining (2005)
Abstract—Irrelevant attributes add noise to high-dimensional clusters and render traditional clustering techniques inappropriate. Recently, several algorithms that discover projected clusters and...
Tao, Yufei, Zhang, Jun, Papadias, Dimitris, Mamoulis, Nikos
Existing models for nearest neighbor search in multi-dimensional spaces are not appropriate for query optimization because they either lead to erroneous estimation, or involve complex equations that...
All-nearest-neighbors queries in spatial databases (2004)
Zhang, Jun, Papadias, Dimitris, Mamoulis, Nikos, Tao, Yufei
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...
Complex spatial query processing (2004)
Mamoulis, Nikos, Papadias, Dimitris, Arkoumanis, Dinos
The user of a Geographical Information System is not limited to conventional spatial selections and joins, but may also pose more complicated and descriptive queries. In this paper we focus on the...
Discovering partial periodic patterns in discrete data sequences (2004)
Huiping Cao, David W. Cheung, Nikos Mamoulis
Abstract. The problem of partial periodic pattern mining in a discrete data sequence is to find subsequences that appear periodically and frequently in the data sequence. Two essential subproblems...
Yufei Tao, Dimitris Papadias, Jun Zhang, Nikos Mamoulis
Existing models for nearest neighbor search in multi-dimensional spaces are not appropriate for query optimization because they either lead to erroneous estimation, or involve complex equations that...
Algorithms for quantified constraint satisfaction problems (2004)
Nikos Mamoulis, Kostas Stergiou
Abstract. Many propagation and search algorithms have been developed for constraint satisfaction problems (CSPs). In a standard CSP all variables are existentially quantified. The CSP formalism can...
K.: Constraint satisfaction in semi-structured data graphs (2004)
Nikos Mamoulis, Kostas Stergiou
Abstract. XML data can be modeled as node-labeled graphs and XML queries can be expressed by structural relationships between labeled elements. XML query evaluation has been addressed using mainly...
Non-contiguous sequence pattern queries (2004)
Abstract. Non-contiguous subsequence pattern queries search for symbol instances in a long sequence that satisfy some soft temporal constraints. In this paper, we propose a methodology that indexes...
Algorithms for Quantified Constraint Satisfaction Problems (2004)
Nikos Mamoulis, Kostas Stergiou
Many propagation and search algorithms have been developed for constraint satisfaction problems (CSPs). In a standard CSP all variables are existentially quantified. The CSP formalism can be extended...
Yufei Tao, Jun Zhang, Dimitris Papadias, Nikos Mamoulis
Abstract—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...
An efficient and scalable algorithm for clustering xml documents by structure (2004)
Wang Lian, David W. Cheung, Ieee Computer Society, Nikos Mamoulis, Siu-ming Yiu
Abstract—With the standardization of XML as an information exchange language over the net, a huge amount of information is formatted in XML documents. In order to analyze this information...
Validity information retrieval for spatio-temporal queries : theoretical performance bounds (2003)
Tao, Yufei, Mamoulis, Nikos, Papadias, Dimitris
The results of traditional spatial queries (i.e., range search, nearest neighbor, etc.) are usually meaningless in spatio-temporal applications, because they will be invalidated by the movements of...
Evaluation of iceberg distance joins (2003)
Shou, Yutao, Mamoulis, Nikos, Cao, Huiping, Papadias, Dimitris, Cheung, David W.
The iceberg distance joins returns object pairs within some distance from each other, provided that the first object appears at least a number of times in the result, e.g., 'find hotels which are...
Query processing in spatial network databases (2003)
Papadias, Dimitris, Zhang, Jun, Mamoulis, Nikos, Tao, Yufei
Despite the importance of spatial networks in real-life applications, most of the spatial database literature focuses on Euclidean spaces. In this paper we propose an architecture that integrates...
Slot index spatial join (2003)
Mamoulis, Nikos, Papadias, Dimitris
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...
# 2004 Kluwer Academic Publishers. Manufactured in The Netherlands. (2003)
Nikos Mamoulis, Dimitris Papadias, Dinos Arkoumanis
The user of a Geographical Information System is not limited to conventional spatial selections and joins, but may also pose more complicated and descriptive queries. In this paper, we focus on the...
Slot Index Spatial Join (2003)
Nikos Mamoulis, Dimitris Papadias
Abstract—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...
Similarity search in sets and categorical data using the signature tree (2003)
Nikos Mamoulis, David W. Cheung, Wang Lian
Data mining applications analyze large collections of set data and high dimensional categorical data. Search on these data types is not restricted to the classic problems of mining association rules...
Query processing in spatial network databases (2003)
Dimitris Papadias, Nikos Mamoulis
Despite the importance of spatial networks in real-life applications, most of the spatial database literature focuses on Euclidean spaces. In this paper we propose an architecture that integrates...
Validity information retrieval for spatio-temporal queries (2003)
Yufei Tao, Nikos Mamoulis, Dimitris Papadias
Abstract. The results of traditional spatial queries (i.e., range search, nearest neighbor, etc.) are usually meaningless in spatio-temporal applications, because they will be invalidated by the...
Slot Index Spatial Join (2003)
Nikos Mamoulis, Dimitris Papadias
Abstract—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...
View selection using randomized search (2002)
Kalnis, Panagiotis, Mamoulis, Nikos, Papadias, Dimitris
An important issue in data warehouse development is the selection of a set of views to materialize in order to accelerate OLAP queries, given certain space and maintenance time constraints. Existing...
Indexing and retrieval of historical aggregate information about moving objects (2002)
Papadias, Dimitris, Tao, Yufei, Zhang, Jun, Mamoulis, Nikos, Shen, Qiongmao, Sun, Jimeng
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...
View Selection Using Randomized Search (2002)
Panos Kalnis, Nikos Mamoulis, Dimitris Papadias
An important issue in data warehouse development is the selection of a set of views to materialize in order to accelerate OLAP queries, given certain space and maintenance time constraints. Existing...
Indexing and Retrieval of Historical Aggregate Information about Moving Objects (2002)
Dimitris Papadias Yufei, Dimitris Papadias, Yufei Tao, Jun Zhang, Nikos Mamoulis, Qiongmao Shen, ...
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...
Indexing and retrieval of historical aggregate information about moving objects (2002)
Dimitris Papadias, Yufei Tao, Jun Zhang, Nikos Mamoulis, Qiongmao Shen, Jimeng Sun
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...
Selectivity estimation of complex spatial queries (2001)
Papadias, Dimitris, Mamoulis, Nikos
Several studies have focused on the efficient processing of simple spatial query types such as selections and spatial joins. Little work, however, has been done towards the optimization of queries...
Mamoulis, Nikos, Papadias, Dimitris
Due to the evolution of Geographical Information Systems, large collections of spatial data having various thematic contents are currently available. As a result, the interest of users is not limited...
Approximate spatio-temporal retrieval (2001)
Papadias, Dimitris, Mamoulis, Nikos, Delis, Vasilis
This paper proposes a framework for the handling of spatio-temporal queries with inexact matches, using the concept of relation similarity. We initially describe a binary string encoding for 1D...
Solving Non-binary CSPs Using the Hidden Variable Encoding (2001)
Nikos Mamoulis, Kostas Stergiou
Abstract. Non-binary constraint satisfaction problems (CSPs) can be solved in two different ways. We can either translate the problem into an equivalent binary one and solve it using well-established...
Due to the evolution of Geographical Information Systems, large collections of spatial data having various thematic contents are currently available. As a result, the interest of users is not limited...
A survey on multidimensional access methods (2001)
Hee-kap Ahn, Hee Kap Ahn, Nikos Mamoulis, Nikos Mamoulis, Ho Min Wong, Ho Min Wong
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...
Constraint-Based Processing of Multiway Spatial Joins (2001)
Dimitris Papadias, Nikos Mamoulis, Yannis 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...
Selectivity estimation of complex spatial queries (2001)
Nikos Mamoulis, Dimitris Papadias
Abstract. Several studies have focused on the efficient processing of simple spatial query types such as selections and spatial joins. Little work, however, has been done towards the optimization of...
A survey on multidimensional access methods (2001)
Hee Kap Ahn, Nikos Mamoulis, Ho Min Wong
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...
Selectivity estimation of complex spatial queries (2001)
Nikos Mamoulis, Dimitris Papadias, Dimitris Papadias
This paper studies selectivity estimation for complex spatial queries. Although there have been several studies on the efficient processing of simple spatial query types such as selections and...
Efficient Image Retrieval by Exploiting Vertical Fragmentation (2001)
Nikos Mamoulis, Niels J. Nes, Martin L. Kersten
Information Systems Efficient image retrieval by exploiting vertical fragmentation A.P. de Vries, N. Mamoulis, N.J. Nes, M.L. Kersten
Nikos Mamoulis, Dimitris Papadias
Due to the evolution of Geographical Information Systems, large collections of spatial data representing various thematic contents are currently available. As a result, the interest of users is not...
Content-based retrieval using heuristic search (1999)
Papadias, Dimitris, Mantzourogiannis, Marios, Kalnis, Panagiotis, Mamoulis, Nikos, Ahmad, Ishfaq
The fast growth of multimedia information in image and video databases has triggered research on efficient retrieval methods. This paper deals with structural queries, a type of content-based...
Hierarchical constraint satisfaction in spatial databases (1999)
Papadias, Dimitris, Kalnis, Panagiotis, Mamoulis, Nikos
Several content-based queries in spatial databases and geographic information systems (GISs) can be modelled and processed as constraint satisfaction problems (CSPs). Regular CSP algorithms, however,...
Improving search using indexing : a study with temporal CSPs (1999)
Mamoulis, Nikos, Papadias, Dimitris
Most studies concerning constraint satisfaction problems (CSPs) involve variables that take values from small domains. This paper deals with an alternative form of temporal CSPs; the number of...
Processing and optimization of multiway spatial joins using R-trees (1999)
Papadias, Dimitris, Mamoulis, Nikos, Theodoridis, Yannis
One of the most important types of query processing in spatial databases and geographic information systems is the spatial join, an operation that selects, from two relations, all object pairs...
Integration of spatial join algorithms for processing multiple inputs (1999)
Mamoulis, Nikos, Papadias, Dimitris
Several techniques that compute the join between two spatial datasets have been proposed during the last decade. Among these methods, some consider existing indices for the joined inputs, while...
Content-Based Retrieval using Heuristic Search (1999)
Dimitris Papadias, Marios Mantzourogiannis, Panos Kalnis, Nikos Mamoulis, Ishfaq Ahmad
Algorithms for querying by spatial structure (1998)
Papadias, Dimitris, Mamoulis, Nikos, Delis, Vasilis
Structural queries constitute a special form of content-based retrieval where the user specifies a set of spatial constraints among query variables and asks for all configurations of actual objects...
Assessing multimedia similarity : A framework for structure and motion (1998)
Delis, Vasilis, Papadias, Dimitris, Mamoulis, Nikos
In this paper we address the issue of structural multimedia similarity, which is based on the relations between the individual objects that comprise a multimedia document. We propose a binary string...
Constraint-based algorithms for computing clique intersection joins (1998)
Mamoulis, Nikos, Papadias, Dimitris
Spatial joins constitute one of the most active research topics in spatial query processing. This paper deals with the processing of clique intersection joins using R-trees. A clique intersection...
Image similarity retrieval by spatial constraints (1998)
Papadias, Dimitris, Mamoulis, Nikos, Meretakis, Dimitris
This paper deals with queries involving the retrieval of images that contain certain object configurations. Consider, for instance, that a user wants to "find all images where there exists a building...
Algorithms for Querying by Spatial Structure (1998)
Dimitris Papadias, Nikos Mamoulis, Vasilis Delis
Abstract: Structural queries constitute a special form of content-based retrieval where the user specifies a set of spatial constraints among query variables and searches for all configurations of...
Image Similarity Retrieval by Spatial Constraints (1998)
Dimitris Papadias, Nikos Mamoulis, Dimitris Meretakis
This paper deals with queries involving the retrieval of images that contain certain object configurations. Consider, for instance, that a user wants to “find all images where there exists a...
Algorithms for Querying by Spatial Structure (1998)
Dimitris Papadias, Nikos Mamoulis, Vasilis Delis
Abstract: Structural queries constitute a special form of content-based retrieval where the user specifies a set of spatial constraints among query variables and asks for all configurations of actual...
Constraint-based Algorithms for Computing Clique Intersection Joins (1998)
Spatial joins constitute one of the most active research topics in spatial query processing. This paper deals with the processing of clique intersection joins using R-trees. A clique intersection...
Integration of Spatial Join Algorithms for Joining Multiple Inputs (1998)
Nikos Mamoulis, Dimitris Papadias
Several techniques that compute the join between two spatial datasets have been proposed during the last decade. Among these methods, some consider existing indices for the joined inputs, while...
Algorithms for Querying by Spatial Structure (1998)
Dimitris Papadias, Nikos Mamoulis, Vasilis Delis
: Structural queries constitute a special form of content-based retrieval where the user specifies a set of spatial constraints among query variables and asks for all configurations of actual objects...
Assessing Multimedia Similarity: A Framework for Structure and Motion (1998)
Vasilis Delis, Dimitris Papadias, Nikos Mamoulis
In this paper we address the issue of structural multimedia similarity, which is based on the relations between the individual objects that comprise a multimedia document. We propose a binary string...
Processing and Optimization of Multiway Spatial Joins Using R-trees (1998)
Dimitris Papadias, Nikos Mamoulis, Yannis Theodoridis
One of the most important types of query processing in spatial databases and geographic information systems is the spatial join, an operation that selects, from two relations, all object pairs...
A Survey on Multidimensional Access Methods (1997)
Hee Kap Ahn, Nikos Mamoulis, Ho Min Wong
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...
Processing ad-hoc joins on mobile devices, in (1996)
Eric Lo, Nikos Mamoulis, David W. Cheung, Wai Shing Ho, Panos Kalnis
Abstract. Mobile devices are capable of retrieving and processing data from remote databases. In a wireless data transmission environment, users are typically charged by the size of transferred data,...