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Nikos Mamoulis

Researcher at University of Ioannina

Publications -  294
Citations -  12127

Nikos Mamoulis is an academic researcher from University of Ioannina. The author has contributed to research in topics: Joins & Spatial query. The author has an hindex of 56, co-authored 282 publications receiving 11121 citations. Previous affiliations of Nikos Mamoulis include University of Hong Kong & Max Planck Society.

Papers
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Proceedings ArticleDOI

Lattice Histograms: a Resilient Synopsis Structure

TL;DR: The lattice histogram is introduced: a novel data reduction method that discovers and exploits any arbitrary hierarchy in the data, and achieves approximation quality provably at least as high as an optimal histogram for any data reduction problem.
Book ChapterDOI

Constraint satisfaction in semi-structured data graphs

TL;DR: In this article, the authors propose an alternative method that models and solves such queries as constraint satisfaction problems (CSPs) and describe common constraint types occurring in XML queries and show how query evaluation can benefit from methods for preprocessing and solving CSPs.
Journal ArticleDOI

Extracting k most important groups from data efficiently

TL;DR: This work designs the clustered groups algorithm (CGA), which accelerates top-k groups processing for the case where data is clustered by a subset of group-by attributes and develops the recursive hash algorithm (RHA), which applies hashing with early aggregation, coupled with branch-and-bound techniques and derivation heuristics for tight score bounds of hash partitions.
Proceedings ArticleDOI

Parallel and Distributed Processing of Spatial Preference Queries using Keywords

TL;DR: This paper studies the novel problem of parallel and distributed processing of spatial preference queries using keywords, where the input data is stored in a distributed way and proposes parallel algorithms that solve the problem in the MapReduce framework.
Proceedings ArticleDOI

Image similarity retrieval by spatial constraints

TL;DR: This paper focuses on the development of effective methods that take advantage of the special structure of the spatial domain to achieve good average performance even for large images and queries.