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Enabling Fine-grained RDF Data Completeness Assessment [article]

Fariz Darari, Simon Razniewski, Radityo Eko Prasojo, Werner Nutt
2016 arXiv   pre-print
We verify the applicability of our framework using Wikidata and develop COOL-WD, a completeness tool for Wikidata, used to annotate Wikidata with completeness statements and reason about the completeness  ...  In this paper we develop a technique to check query completeness based on RDF data annotated with completeness information, taking into account data-specific inferences that lead to an inference problem  ...  The research was supported by the projects "CANDy: Completeness-Aware Querying and Navigation on the Web of Data" and "TaDaQua -Tangible Data Quality with Object Signatures" of the Free University of Bozen-Bolzano  ... 
arXiv:1604.08377v1 fatcat:r4kuzxej6fdjxeydby42zgdrk4

ELITE: An Entailment-Based Federated Query Engine for Complete and Transparent Semantic Data Integration

Andreas Nolle, German Nemirovski
2013 International Workshop on Description Logics  
ELITE thereby enables the integration of various kinds of data sources, for example as relational databases or triple stores, simplicity of query design, guaranteed completeness of query results and highly  ...  This paper presents the federated query engine ELITE that facilitates a complete and transparent integration and querying of distributed autonomous data sources.  ...  Mariano Rodríguez-Muro for providing us the source code of Quest as well as for supporting.  ... 
dblp:conf/dlog/NolleN13 fatcat:q4qzepg5ifgf7pdri3iwh7mivi

Query Processing in a Mediator Based Framework for Linked Data Integration

Vânia M. P. Vidal, José A. F. de Macêdo, João C. Pinheiro, Marco A. Casanova, Fábio Porto
2011 International Journal of Business Data Communications and Networking  
The main contribution of the paper is an algorithm for reformulating a user query into sub-queries over the data sources.  ...  In this paper, we present a three-level mediator based framework for linked data integration.  ...  We provide a sound and complete algorithm for reformulating a SPARQL query into a query over the (linked) data sources.  ... 
doi:10.4018/jbdcn.2011040103 fatcat:mxxb6w3xpjg2xhlllaonuur2ly

Rewriting queries on SPARQL views

Wangchao Le, Songyun Duan, Anastasios Kementsietsidis, Feifei Li, Min Wang
2011 Proceedings of the 20th international conference on World wide web - WWW '11  
For an input SPARQL query over a set of virtual SPARQL views, the rewritten query resembles a union of conjunctive queries and can be of exponential size.  ...  We approach this problem by rewriting SPARQL queries over the views to equivalent queries over the underlying RDF data, thus avoiding the costs entailed by view materialization and maintenance.  ...  ACKNOWLEDGMENT This work was done in part when Wangchao Le (intern) and Min Wang were with IBM. Wangchao Le and Feifei Li were partially supported by NSF Grant CNS-0831278.  ... 
doi:10.1145/1963405.1963497 dblp:conf/www/LeDKLW11 fatcat:2n2hzhilqrc3hmtq33lar6xnrm

Leveraging flexible data management with graph databases

Elena Vasilyeva, Maik Thiele, Christof Bornhövd, Wolfgang Lehner
2013 First International Workshop on Graph Data Management Experiences and Systems - GRADES '13  
The proposed integration approach extends the internal graph model with external data from the Linked Open Data cloud, which stores over 31 billion RDF triples (September 2011) from a variety of domains  ...  For this reason, enterprises often lack information regarding the current market situation, preventing a holistic view that is needed to conduct sound data analysis and market predictions.  ...  RDF/RDFS data can be accessed via SPARQL [15] , which supports queries among diverse sources of data in the RDF format.  ... 
doi:10.1145/2484425.2484437 dblp:conf/sigmod/VasilyevaTBL13 fatcat:ganlepwvz5dkfam74xzfjttnm4

Querying for provenance, trust, uncertainty and other meta knowledge in RDF☆

Renata Dividino, Sergej Sizov, Steffen Staab, Bernhard Schueler
2009 Journal of Web Semantics  
Thus, our approach achieves highly flexible and automatically coordinated querying for data and meta knowledge, while completely separating the two areas of concern.  ...  Then, it extends SPARQL query processing in such a way that given a SPARQL query for data, one may request meta knowledge without modifying the query proper.  ...  Acknowledgements This work was supported by the X-Media project ( funded by the European Commission under EC grant number IST-FP6-026978 and by the project WeKnowIt (  ... 
doi:10.1016/j.websem.2009.07.004 fatcat:xtlzmhhuajdufcb77rpygnmnyu

LiteMat: a scalable, cost-efficient inference encoding scheme for large RDF graphs [article]

Olivier Curé, Hubert Naacke, Tendry Randriamalala, Bernd Amann
2015 arXiv   pre-print
For instance, to complete the answer set of SPARQL queries, RDF database systems evaluate semantic RDFS relationships (subPropertyOf, subClassOf) through time-consuming query rewriting algorithms or space-consuming  ...  As a consequence, semantic RDF services are more and more confronted with various "big data" problems. Query processing in the presence of inferences is one them.  ...  With such workloads, RDF database systems are now facing "big data" problems. In this work, we focus on issues related to SPARQL query processing over large RDF data with rich semantics.  ... 
arXiv:1510.03409v1 fatcat:yaz64mu6y5fezi56uhxqoromay

Using Reformulation Trees to Optimize Queries over Distributed Heterogeneous Sources [chapter]

Yingjie Li, Jeff Heflin
2010 Lecture Notes in Computer Science  
In order to effectively and quickly answer queries in environments with distributed RDF/OWL, we present a query optimization algorithm to identify the potentially relevant Semantic Web data sources using  ...  Finally, we use an OWL reasoner to answer queries over the selected sources and their corresponding ontologies.  ...  Then the Loader reads the selected sources together with their corresponding ontologies and inputs them into a sound and complete OWL Reasoner, which is then queried to produce results.  ... 
doi:10.1007/978-3-642-17746-0_32 fatcat:ji2lb3h42nchjbqfwjs5usxfj4

SPARQL for a Web of Linked Data: Semantics and Computability [chapter]

Olaf Hartig
2012 Lecture Notes in Computer Science  
The World Wide Web currently evolves into a Web of Linked Data where content providers publish and link data as they have done with hypertext for the last 20 years.  ...  While the declarative query language SPARQL is the de facto for querying a-priory defined sets of data from the Web, no language exists for querying the Web of Linked Data itself.  ...  Completeness and Infiniteness Definition 12 defines precisely what the sound and complete result of any SPARQL LD(R) query Q P,S c over any Web of Linked Data W is.  ... 
doi:10.1007/978-3-642-30284-8_8 fatcat:4b62wjtcfjfxnm3gwduos2ir54

Linked Data Query Processing Based on Link Traversal [chapter]

Olaf Hartig
2014 Emerging Directions in Database Systems and Applications  
As a consequence of these limited data access capabilities not any approach for executing SPARQL LD queries over a Web of Data such as the WWW can guarantee complete query results.  ...  Introduction The execution of SPARQL queries over Linked Data readily available from a large number of sources provides enormous potential.  ... 
doi:10.1201/b16859-15 fatcat:uswyftr2hvecnmsko5u7xyrecu

Advancing the Enterprise-class OWL Inference Engine in Oracle Database

Zhe Wu, Karl Rieb, George Eadon, Ankesh Khandelwal, Vladimir Kolovski
2012 International Workshop on OWL Reasoner Evaluation  
In this paper, we discuss our recent implementation and optimization techniques for query-rewrite based OWL 2 QL reasoning, named graph-based inference (local inference), and integration with external  ...  Since 2006, we have been developing an RDBMS-based large scale and efficient forward-chaining inference engine capable of handling RDF(S), OWL 2 RL/RDF, SKOS, and user defined rules.  ...  We thank Jay Banerjee for his support. We thank Rick Hetherington and Brian Whitney for providing access to and guiding us on the use of the Oracle Sun M8000 server machine.  ... 
dblp:conf/ore/WuREKK12 fatcat:isinrkr7zzekdg7yc2ji4fzgl4

A logical characterisation of SPARQL federation

Audun Stolpe, Oscar Corcho
2014 Semantic Web Journal  
The paper provides a logical characterisation of distributed processing of SPARQL conjunctive queries.  ...  These are named the even-, standard-and prudent distribution and yield sound and complete federation schemes when paired with an evaluation rule named the collect-and-combine rule.  ...  conjunctive queries to multiple sources: standard SPARQL semantics defines the evaluation S G of a BGP S over an RDF graph G in terms of partial functions or maps from variables to RDF terms, and it defines  ... 
doi:10.3233/sw-140160 fatcat:fmmihxibzfbdrk4envez3iwunu

Containment and Minimization of RDF/S Query Patterns [chapter]

Giorgos Serfiotis, Ioanna Koffina, Vassilis Christophides, Val Tannen
2005 Lecture Notes in Computer Science  
In this paper, we present sound and complete algorithms for the containment and minimization of RDF/S query patterns.  ...  Semantic query optimization (SQO) has been proved to be quite useful in various applications (e.g., data integration, graphical query generators, caching, etc.) and has been extensively studied for relational  ...  Acknowledgements We would like to thank Alin Deutsch and Nicola Onose for fruitful discussions on relational and XML SQO.  ... 
doi:10.1007/11574620_44 fatcat:hv5f6blgxfbinjvlsy2m4ntk64

OntoSIDES: Ontology-based student progress monitoring on the national evaluation system of French Medical Schools

Olivier Palombi, Fabrice Jouanot, Nafissetou Nziengam, Behrooz Omidvar-Tehrani, Marie-Christine Rousset, Adam Sanchez
2019 Artificial Intelligence in Medicine  
OntoSIDES is an RDF knowledge base comprised of a lightweight domain ontology that serves as a pivot high-level vocabulary of the query interface with users, and of a dataset made of factual statements  ...  and related to items of an official reference program in a unified RDF data model.  ...  RDF and SPARQL are standards recommended by W3C for the Semantic Web and Linked Data 3 .  ... 
doi:10.1016/j.artmed.2019.03.006 pmid:31164211 fatcat:aduhx6vojrdkblokkuhbzdemva

SPARQL Query Containment Under Schema

Melisachew Wudage Chekol, Jérôme Euzenat, Pierre Genevès, Nabil Layaïda
2018 Journal on Data Semantics  
For that purpose, we define an RDF graph encoding as a transition system which preserves its characteristics. In addition, queries and schema axioms are encoded as µ-calculus formulae.  ...  Thereby, query containment can be reduced to testing validity in the logic. We identify various fragments of SPARQL and description logic schema languages for which containment is decidable.  ...  The NP-completeness is established for query containment concerning conjunctive and union of conjunctive queries.  ... 
doi:10.1007/s13740-018-0087-1 fatcat:2jxq2bg5zncutjhgqw4lewyypa
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