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OptiqueVQS: Visual Query Formulation for OBDA

Ahmet Soylu, Evgeny Kharlamov, Dmitriy Zheleznyakov, Ernesto Jiménez-Ruiz, Martin Giese, Ian Horrocks
2014 International Workshop on Description Logics  
We use OWL 2 QL ontologies for query rewriting, while the query construction is based on much richer OWL 2 ontologies that, in particular, make use of nominals.  ...  There are both theoretical and practical reasons for having two ontologies: conjunctive query rewriting for OBDA is well studied for OWL 2 QL ontologies [6] , while for effective and efficient query support  ... 
dblp:conf/dlog/SoyluKZJGH14 fatcat:pw3mr3jxpfhxjmpn3mofkbbuxa

Succinctness of Query Rewriting in OWL 2 QL: The Case of Tree-like Queries

Meghyn Bienvenu, Stanislav Kikot, Vladimir V. Podolskii
2014 International Workshop on Description Logics  
This paper further investigates the succinctness landscape of query rewriting in OWL 2 QL.  ...  More specifically, we establish a superpolynomial lower bound on the size of PE-rewritings that holds already for linear queries and TBoxes of depth 2.  ...  This work was partially supported by ANR grant 12-JS02-007-01, Russian Foundation for Basic Research and the programme "Leading Scientific Schools".  ... 
dblp:conf/dlog/BienvenuKP14 fatcat:7zioleyxpbdj7lnxr6q4ndmepq

Efficient Query Answering for OWL 2 [chapter]

Héctor Pérez-Urbina, Ian Horrocks, Boris Motik
2009 Lecture Notes in Computer Science  
The QL profile of OWL 2 has been designed so that it is possible to use database technology for query answering via query rewriting.  ...  The results indicate that our algorithm produces significantly smaller rewritings in most cases, which could be important for practicality in realistic applications. 1  ...  The OWL 2 QL profile was designed to allow query answering via query rewriting: a query over an OWL 2 QL ontology and a set of instance data stored in a data repository can be answered by rewriting the  ... 
doi:10.1007/978-3-642-04930-9_31 fatcat:rxbnpnhfrjfujm3oz3sir6obxm

Using OWL in Data Integration [chapter]

Diego Calvanese, Giuseppe De Giacomo, Domenico Lembo, Maurizio Lenzerini, Riccardo Rosati, Marco Ruzzi
2009 Semantic Web Information Management  
In particular, we adopt OWL 2 QL as the ontology language used to express the global schema.  ...  OWL 2 QL is one of the tractable profiles of OWL 2, and essentially corresponds to a member of the DL-Lite family, a family of Description Logics designed to have a good trade-off between expressive power  ...  We will show that expressing the global schema in OWL 2 QL allows for efficient query answering.  ... 
doi:10.1007/978-3-642-04329-1_17 fatcat:tll42v56mzfbfmditjlz56j7uq

Ontop: Answering SPARQL queries over relational databases

Diego Calvanese, Benjamin Cogrel, Sarah Komla-Ebri, Roman Kontchakov, Davide Lanti, Martin Rezk, Mariano Rodriguez-Muro, Guohui Xiao, Óscar Corcho
2016 Semantic Web Journal  
exploiting all elements of the OBDA architecture, its compliance to all relevant W3C recommendations (including SPARQL queries, R2RML mappings, and OWL 2 QL and RDFS ontologies), and its support for all  ...  Key features of Ontop are its solid theoretical foundations, a virtual approach to OBDA, which avoids materializing triples and is implemented through the query rewriting technique, extensive optimizations  ...  This query rewriting system supports reasoning over OWL 2 QL ontologies.  ... 
doi:10.3233/sw-160217 fatcat:mjwgfop5tvfvpf3rr6flpfvmwq

Extending NoHR for OWL 2 QL

Nuno Costa, Matthias Knorr, João Leite
2015 International Joint Conference on Artificial Intelligence  
In this paper, we provide the nontrivial solution for the extension of NoHR to OWL 2 QL by directly translating the ontology into rules without any prior pre-processing or classification.  ...  Yet, a straightforward adaptation of the existing approach to OWL 2 QL turns out to not be viable.  ...  to O, which would allow us to derive the queried goal.  ... 
dblp:conf/ijcai/CostaKL15 fatcat:72v7jq34ljbormnlzkotvvtaxi

OWL as Yet Another Data Model to be Integrated

Leonid A. Kalinichenko, Sergey A. Stupnikov
2011 Symposium on Advances in Databases and Information Systems  
Applying the SYNTHESIS -an extensible language for heterogeneous information resource integration and mediator definition -we show how a sound mapping of a conceptual schemas expressed in OWL 2 QL into  ...  The paper shows also how the integration of the OWL-defined databases into a SYNTHESIS-based mediator can be provided.  ...  Views are crucial for rewriting queries over mediator into queries over resources.  ... 
dblp:conf/adbis/KalinichenkoS11 fatcat:bcbf5lw4u5dqxajrffy3apfx4y

Tree-like Queries in OWL 2 QL: Succinctness and Complexity Results [article]

Meghyn Bienvenu and Stanislav Kikot and Vladimir Podolskii
2015 arXiv   pre-print
This paper investigates the impact of query topology on the difficulty of answering conjunctive queries in the presence of OWL 2 QL ontologies.  ...  Perhaps our most surprising result is a superpolynomial lower bound on the size of PE-rewritings that holds already for linear queries and ontologies of depth 2.  ...  Our results also have practical implications for querying OWL 2 QL KBs.  ... 
arXiv:1406.3047v2 fatcat:bcenz67hjrabzahn54nsngyde4

Tree-like Queries in OWL 2 QL: Succinctness and Complexity Results

Meghyn Bienvenu, Stanislav Kikot, Vladimir Podolskii
2015 2015 30th Annual ACM/IEEE Symposium on Logic in Computer Science  
This paper investigates the impact of query topology on the difficulty of answering conjunctive queries in the presence of OWL 2 QL ontologies.  ...  For FO-rewritings, we equate the existence of polysize rewritings with well-known problems in Boolean circuit complexity.  ...  Our results also have practical implications for querying OWL 2 QL KBs.  ... 
doi:10.1109/lics.2015.38 dblp:conf/lics/BienvenuKP15 fatcat:uyvmchmjbvdyrm7xidl55svxc4

Integrating Databases into the Semantic Web through an Ontology-Based Framework

Dejing Dou, P. LePendu, Shiwoong Kim, Peishen Qi
2006 22nd International Conference on Data Engineering Workshops (ICDEW'06)  
A powerful inference engine, OntoEngine, can be used for query answering and data translation.  ...  In this paper, besides introducing new ideas in the OntoGrate system, we will elaborate on two case studies for which our system works well.  ...  If that, we just need to provide functions in PDDOWL to translate OWL-QL queries into Web-PDDL queries.  ... 
doi:10.1109/icdew.2006.68 dblp:conf/icde/DouLKQ06 fatcat:xjmzy3s7yfam3iuik5a7253k3u

Computing Datalog Rewritings beyond Horn Ontologies [article]

Bernardo Cuenca Grau, Boris Motik, Giorgos Stoilos, Ian Horrocks
2013 arXiv   pre-print
Rewriting-based approaches for answering queries over an OWL 2 DL ontology have so far been developed mainly for Horn fragments of OWL 2 DL.  ...  Our procedure necessarily terminates on DL-Lite_bool^H ontologies---an extension of OWL 2 QL with transitive roles and Boolean connectives.  ...  We extend this result to all ground queries and thus obtain a goal-oriented rewriting algorithm that may be suitable for practical use.  ... 
arXiv:1304.1402v2 fatcat:qriophzrpnegnd6k4ak74slona

Distributed Query Processing on the Cloud: the Optique Point of View (Short Paper)

Herald Kllapi, Dimitris Bilidas, Ian Horrocks, Yannis E. Ioannidis, Ernesto Jiménez-Ruiz, Evgeny Kharlamov, Manolis Koubarakis, Dmitriy Zheleznyakov
2013 W3C Web Ontology Language (OWL) Experiences and Directions Workshop (OWLED)  
The engine aims at providing a scalable solution for query execution in the Cloud, and should cope with heterogeneity of data sources as well as with temporal and streaming data.  ...  The Optique European project 3 [6] aims at providing an end-to-end solution for scalable access to Big Data integration, where end users will formulate queries based on a familiar conceptualization of  ...  In the Optique project we will push the barrier and provide massively parallel and elastic solutions for query optimisation and execution over Big Data integration.  ... 
dblp:conf/owled/KllapiBHIJKKZ13 fatcat:td37tswk35clveokyztjx4mmgm

Faceted Search over Ontology-Enhanced RDF Data

Marcelo Arenas, Bernardo Cuenca Grau, Evgeny Kharlamov, Sarunas Marciuska, Dmitriy Zheleznyakov
2014 Proceedings of the 23rd ACM International Conference on Conference on Information and Knowledge Management - CIKM '14  
We formalise faceted interfaces for this context, identify a fragment of first-order logic capturing the underlying queries, and study the complexity of answering such queries for RDF and OWL 2 profiles  ...  An increasing number of applications rely on RDF, OWL 2, and SPARQL for storing and querying data. SPARQL, however, is not targeted towards end-users, and suitable query interfaces are needed.  ...  In contrast, the evaluation of acyclic CQs is already NP-hard for OWL 2 QL [20] and we can show that faceted query evaluation is NP-complete for OWL 2 QL.  ... 
doi:10.1145/2661829.2662027 dblp:conf/cikm/ArenasGKMZ14 fatcat:7crqtm47endwpnlmasavgt7xne

Ontology-based data access – Beyond relational sources

Elena Botoeva, Diego Calvanese, Benjamin Cogrel, Julien Corman, Guohui Xiao, Chiara Ghidini, Bernardo Magnini, Andrea Passerini
2019 Intelligenza Artificiale  
To enable access to such data, we generalize the well-known ontology-based data access (OBDA) framework so as to allow for querying arbitrary data sources using sparql.  ...  We propose an architecture for a generalized OBDA system implementing the virtual approach.  ...  Typically, in OBDA, the ontology T is expressed in owl 2 ql, and the corresponding entailment regime is that of owl 2 ql [14] .  ... 
doi:10.3233/ia-190023 fatcat:yvfgbymmtjgsdo7pty22pkumx4

Ontology-based data integration in EPNet: Production and distribution of food during the Roman Empire

Diego Calvanese, Pietro Liuzzo, Alessandro Mosca, José Remesal, Martin Rezk, Guillem Rull
2016 Engineering applications of artificial intelligence  
Over the last decades, an immense amount of new quantifiable data have been accumulated, and made available in interchangeable formats, in social sciences and humanities, opening up new possibilities for  ...  translating the conceptual model into an OWL 2 QL ontology.  ...  Instead, for expressing ontologies in the OBDA and OBDI setting, the most commonly used language is OWL 2 QL 15 , which is the profile (i.e., sub-language, in W3C terminology) of OWL 2 that is specifically  ... 
doi:10.1016/j.engappai.2016.01.005 fatcat:4w47hmpgm5e6hi7q6bu7vwfktq
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