Developing Query Patterns

Constantopoulos, Panos; Dritsou, Vicky; Foustoucos, Eugenie

doi:10.1007/978-3-642-04346-8_13

Cited by 4 publications

(1 citation statement)

References 12 publications

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“…The structure of this dataand of its underlying ontologies -is commonly seen as a directed graph, with nodes representing concepts and edges representing relationships between concepts. A basic issue that semantic repositories need to address is the formulation of ontology-based queries, often by repeatedly traversing particular paths [11] of large data graphs. Regardless of the specific model used to store these data graphs (RDF/OWL files, relational databases, etc.…”

Section: Introductionmentioning

confidence: 99%

Optimizing Query Shortcuts in RDF Databases

Dritsou

Constantopoulos

Deligiannakis

et al. 2011

The Semanic Web: Research and Applications

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The emergence of the Semantic Web has led to the creation of large semantic knowledge bases, often in the form of RDF databases. Improving the performance of RDF databases necessitates the development of specialized data management techniques, such as the use of shortcuts in the place of path queries. In this paper we deal with the problem of selecting the most beneficial shortcuts that reduce the execution cost of path queries in RDF databases given a space constraint. We first demonstrate that this problem is an instance of the quadratic knapsack problem. Given the computational complexity of solving such problems, we then develop an alternative formulation based on a bi-criterion linear relaxation, which essentially seeks to minimize a weighted sum of the query cost and of the required space consumption. As we demonstrate in this paper, this relaxation leads to very efficient classes of linear programming solutions. We utilize this bi-criterion linear relaxation in an algorithm that selects a subset of shortcuts to materialize. This shortcut selection algorithm is extensively evaluated and compared with a greedy algorithm that we developed in prior work. The reported experiments show that the linear relaxation algorithm manages to significantly reduce the query execution times, while also outperforming the greedy solution.

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Section: Introductionmentioning

confidence: 99%

Optimizing Query Shortcuts in RDF Databases

Dritsou

Constantopoulos

Deligiannakis

et al. 2011

The Semanic Web: Research and Applications

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Adaptation of NLP Techniques to Cultural Heritage Research and Documentation

Goerz

Scholz

2010

CIT

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The WissKI system provides a framework for ontologybased science communication and cultural heritage documentation. In many cases, the documentation consists of semi-structured data records with free text fields. Most references in the texts comprise of person and place names, as well as time specifications. We present the WissKI tools for semantic annotation using controlled vocabularies and formal ontologies derived from CIDOC Conceptual Reference Model (CRM). Current research deals with the annotations as building blocks for event recognition. Finally, we outline how the CRM helps to build bridges between documentation in different scientific disciplines.

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Materialized View Selection Scheme for enhancing RDF Query Performance

Park¹,

Yoon²,

Choi³

et al. 2015

The Journal of the Korea Contents Association

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With the development of the semantic web, a large amount of data being produced nowadays is in RDF format. RDF is represented by a triple. An RDF database consisting of triples requires the high cost of join query processing. Materialized view is known as a scheme to reduce the query processing cost by accessing materialized views without accessing the database. It is physically stored the results or the intermediate results of the query processing in a storage area. In this paper, we propose a materialized view selection scheme by using decision tree to solve such a problem. The decision tree considers the size and maintenance costs of the materialized view as well as the profit of query response times. It is shown through performance evaluation that the proposed scheme increases the number of materialized views in the limited storage space and decreases the update rates of the materialized views.■ keyword :|RDF|Decision Tree|Materialized View|Shortcut|

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Developing Query Patterns

Cited by 4 publications

References 12 publications

Optimizing Query Shortcuts in RDF Databases

Optimizing Query Shortcuts in RDF Databases

Adaptation of NLP Techniques to Cultural Heritage Research and Documentation

Materialized View Selection Scheme for enhancing RDF Query Performance

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