Filters








837 Hits in 4.0 sec

On the succinctness of query rewriting over shallow ontologies

Stanislav Kikot, Roman Kontchakov, Vladimir V. Podolskii, Michael Zakharyaschev
2014 Proceedings of the Joint Meeting of the Twenty-Third EACSL Annual Conference on Computer Science Logic (CSL) and the Twenty-Ninth Annual ACM/IEEE Symposium on Logic in Computer Science (LICS) - CSL-LICS '14  
We also analyse rewritings of tree-shaped queries over arbitrary ontologies and note that query entailment for such queries is fixed-parameter tractable.  ...  We show that, over ontologies of depth 1, conjunctive queries have polynomial-size nonrecursive datalog rewritings; tree-shaped queries have polynomial positive existential rewritings; however, in the  ...  Acknowledgments This work was supported by the UK EPSRC project 'ExODA: Integrating Description Logics and Database Technologies for Expressive Ontology-Based Data Access' (EP/H05099X).  ... 
doi:10.1145/2603088.2603131 dblp:conf/csl/KikotKPZ14 fatcat:kcprky32dvfxhcz2qlq5bqf3om

On the Succinctness of Query Rewriting over OWL 2 QL Ontologies with Shallow Chases [article]

Stanislav Kikot, Roman Kontchakov, Vladimir Podolskii, Michael Zakharyaschev
2014 arXiv   pre-print
We also analyse rewritings of tree-shaped queries over arbitrary ontologies and observe that the query entailment problem for such queries is fixed-parameter tractable.  ...  Conjunctive queries over ontologies of depth 1 have polynomial-size nonrecursive datalog rewritings; tree-shaped queries have polynomial positive existential rewritings; however, in the worst case, positive  ...  EPSRC project 'ExODA: Integrating Description Logics and Database Technologies for Expressive Ontology-Based Data Access' (EP/H05099X).  ... 
arXiv:1401.4420v2 fatcat:qbvupdnebzfdrfkbwclsqxifli

Query Rewriting under Ontology Contraction [chapter]

Eleni Tsalapati, Giorgos Stoilos, Giorgos Stamou, George Koletsos
2012 Lecture Notes in Computer Science  
In this paper we study the problem of computing a rewriting for a CQ over an ontology that has been contracted (i.e., some of its axioms have been removed) given a rewriting for the input CQ and ontology  ...  One of the most prominent approaches to conjunctive query answering is query rewriting where a wide variety of systems has been proposed the last years.  ...  is rather 'shallow'.  ... 
doi:10.1007/978-3-642-33203-6_13 fatcat:rz6og253ibgnhmbio2zz7vcazi

Supporting the Development of Data Wrapping Ontologies [chapter]

Lina Lubyte, Sergio Tessaris
2009 Lecture Notes in Computer Science  
Testing Emptiness The rewriting of a CQ over ELHI KB is a datalog query [6] .  ...  Specifically, from [6] we have that given a conjunctive query Q over an ELHI KB K = T , A , we can compute another query Q ′ , a rewriting of Q, such that the certain answers of Q over K and the answers  ... 
doi:10.1007/978-3-642-10871-6_3 fatcat:vu42spgcoza7dj354hsvij52ue

Event Detection and Diagnosis for Intelligent Transport Systems

Patrik Schneider
2017 International Web Rule Symposium  
streams and spatial relations over spatial objects; (c) to provide a technique for query rewriting taking the above into account.  ...  Based on the integration layer with an LDM ontology, we aim to work out an event detection component by extending DL-Lite for query answering over C-ITS streams.  ... 
dblp:conf/ruleml/Schneider17 fatcat:e4ae4odhqfa6fmgknrxvfhsjjm

On Querying Ontologies and Databases [chapter]

Henrik Bulskov, Rasmus Knappe, Troels Andreasen
2004 Lecture Notes in Computer Science  
enduser to tailor the evaluation principle of the system by influencing query expansion in the ontology.  ...  The expressiveness of the proposed query language introduces the possibility for querying both objects in the base but also mechanisms for direct querying of the ontology, and it furthermore enables the  ...  over the query expression in order to query both the text objects in the database, but also to pose queries directly to the structure of the ontology.  ... 
doi:10.1007/978-3-540-25957-2_16 fatcat:i4pakzqnsjco7n7jx5npl47zsi

Supporting the Design of Ontologies for Data Access

Lina Lubyte, Sergio Tessaris
2008 International Workshop on Description Logics  
The benefits of using an ontology over relational data sources to mediate the access to these data are widely accepted and well understood.  ...  In fact, changes to the ontology can be unsupported by the underlying data sources; which means that it is likely that queries against the enriched ontology return empty answers.  ...  Using an appropriate ontology language, this can be done by means of query rewriting techniques (see [9] ).  ... 
dblp:conf/dlog/LubyteT08 fatcat:5snq7zxa3jhktmzztkf7toacte

Ontology-Guided Image Interpretation for GEOBIA of High Spatial Resolution Remote Sense Imagery: A Coastal Area Case Study

Helingjie Huang, Jianyu Chen, Zhu Li, Fang Gong, Ninghua Chen
2017 ISPRS International Journal of Geo-Information  
Web ontology language-query language (OWL-QL) formalize domain knowledge. Then the interpretation matching procedure is implemented by the OWL-QL query-answering.  ...  Both the number of interpreted classes increased (19 classes over 10 classes in Case 1 and 12 classes over seven in Case 2), and the overall accuracy improved (0.77 over 0.55 in Case 1 and 0.86 over 0.65  ...  By the rewriting, the query can be extended to a query of River and a query of Not Flowing Into The Sea.  ... 
doi:10.3390/ijgi6040105 fatcat:py2xxkqn4fflbc4lnv2dbqwyey

The Bag Semantics of Ontology-Based Data Access

Charalampos Nikolaou, Egor V. Kostylev, George Konstantinidis, Mark Kaminski, Bernardo Cuenca Grau, Ian Horrocks
2017 Proceedings of the Twenty-Sixth International Joint Conference on Artificial Intelligence  
The ontology is linked to the sources using mappings, which assign views over the data to ontology predicates.  ...  Ontology-based data access (OBDA) is a popular approach for integrating and querying multiple data sources by means of a shared ontology.  ...  On the succinctness of query rewriting over shallow ontolo- gies. In LICS, 2014. [Reutter. Complexity of answering counting aggregate queries over DL-Lite. J. Web Sem., 33:94-111, 2015.  ... 
doi:10.24963/ijcai.2017/170 dblp:conf/ijcai/NikolaouKKKGH17 fatcat:vmfudao2rzdxjgezmqxkeubtca

The Bag Semantics of Ontology-Based Data Access [article]

Charalampos Nikolaou and Egor V. Kostylev and George Konstantinidis and Mark Kaminski and Bernardo Cuenca Grau and Ian Horrocks
2017 arXiv   pre-print
The ontology is linked to the sources using mappings, which assign views over the data to ontology predicates.  ...  Ontology-based data access (OBDA) is a popular approach for integrating and querying multiple data sources by means of a shared ontology.  ...  On the succinctness of query rewriting over shallow ontolo- gies. In LICS, 2014. [Reutter. Complexity of answering counting aggregate queries over DL-Lite. J. Web Sem., 33:94-111, 2015.  ... 
arXiv:1705.07105v1 fatcat:gcnfenumdrf5jn5x53ddqbciz4

Ontology Based Data Access in Statoil

Evgeny Kharlamov, Dag Hovland, Martin G. Skjæveland, Dimitris Bilidas, Ernesto Jiménez-Ruiz, Guohui Xiao, Ahmet Soylu, Davide Lanti, Martin Rezk, Dmitriy Zheleznyakov, Martin Giese, Hallstein Lie (+4 others)
2017 Journal of Web Semantics  
The ontology is 'connected' to the data via mappings that allow to automatically translate queries posed over the ontology into data-level queries that can be executed by the underlying database management  ...  of translating ontological queries into data queries and their execution over either a single DB of federated DBs; and a query formulation module to support query construction for engineers with a limited  ...  Visual Query Formulation Interfaces over Ontologies.  ... 
doi:10.1016/j.websem.2017.05.005 fatcat:ghpdmsaoizc6bgly4cuyxljvq4

Ontology Based Data Access in Statoil

Evgeny Kharlamov, Dimitris Bilidas, Dag Hovland, Ernesto Jimenez-Ruiz, Davide Lanti, Hallstein Lie, Martin Rezk, Martin G. Skjjveland, Ahmet Soylu, Guohui Xiao, Dimitriy Zheleznyakov, Martin Giese (+4 others)
2017 Social Science Research Network  
The ontology is 'connected' to the data via mappings that allow to automatically translate queries posed over the ontology into data-level queries that can be executed by the underlying database management  ...  of translating ontological queries into data queries and their execution over either a single DB of federated DBs; and a query formulation module to support query construction for engineers with a limited  ...  Visual Query Formulation Interfaces over Ontologies.  ... 
doi:10.2139/ssrn.3199136 fatcat:l23bxm5dgrcolfr4p43cs6efre

OBDA Beyond Relational DBs: A Study for MongoDB

Elena Botoeva, Diego Calvanese, Benjamin Cogrel, Martin Rezk, Guohui Xiao
2016 International Workshop on Description Logics  
We instantiate this framework to MongoDB, a popular JSON-document database, and implement an prototype extension of the virtual OBDA system Ontop for answering SPARQL queries over MongoDB.  ...  arbitrary databases through a mediating ontology.  ...  and future work In [8] , the authors study the problem of ontology-mediated query answering over keyvalue stores.  ... 
dblp:conf/dlog/BotoevaCCRX16 fatcat:bxqg2pfe2japlmqbs3kaqpfzpa

REACTIVE: A Rule-based Framework to Process Reactivity

Elsa Liliana Tovar, Maria-Esther Vidal
2009 International Semantic Web Conference  
In REACTIVE, active ontologies are specified in ActRDFS and queries are expressed in ActSPARQL; these languages respectively extent RDFS and SPARQL to specify data reactive behavior.  ...  that are fired by a set of events in a query.  ...  to manage data changes over time.  ... 
dblp:conf/semweb/TovarV09 fatcat:beu5og5k2na5pjxuekdmsf6dxu

Towards Scalable Instance Retrieval over Ontologies [chapter]

Alissa Kaplunova, Ralf Möller, Sebastian Wandelt, Michael Wessel
2010 Lecture Notes in Computer Science  
In this paper, we consider the problem of query answering over multimedia ontologies.  ...  We propose to overcome this problem with a new so-called filter and refine paradigm for ontology-based query answering.  ...  Given the shallow normal form, we use a so-called ∀-info structure for an ontology O to determine which concepts are (worst-case) propagated over role assertions in an ABox.  ... 
doi:10.1007/978-3-642-15280-1_40 fatcat:p7flolc6lzdqrabzalwhalhawy
« Previous Showing results 1 — 15 out of 837 results