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Certain Answers for SPARQL with Blank Nodes [chapter]

Daniel Hernández, Claudio Gutierrez, Aidan Hogan
2018 Lecture Notes in Computer Science  
We thus explore the feasibility of an alternative SPARQL semantics based on certain answers.  ...  database setting for a core fragment of SPARQL.  ...  Acknowledgements The work was also supported by the Millennium Institute for Foundational Research on Data (IMFD) and by Fondecyt Grant No. 1181896.  ... 
doi:10.1007/978-3-030-00671-6_20 fatcat:imtlfngijzaqtj2fml6cmno6ay

Efficient SPARQL Autocompletion via SPARQL [article]

Hannah Bast, Johannes Kalmbach, Theresa Klumpp, Florian Kramer, Niklas Schnelle
2021 arXiv   pre-print
We show how to achieve fast autocompletion for SPARQL queries on very large knowledge bases.  ...  All suggestions are themselves obtained via SPARQL queries, which we call autocompletion queries. For existing SPARQL engines, these queries are impractically slow on large knowledge bases.  ...  Imagine a valid SPARQL query typed until a certain point, called the cursor position. Let be the part of the body of the SPARQL query until that point.  ... 
arXiv:2104.14595v1 fatcat:hd7xcowdfnco3iuejzqwbttcei

EP-SPARQL

Darko Anicic, Paul Fodor, Sebastian Rudolph, Nenad Stojanovic
2011 Proceedings of the 20th international conference on World wide web - WWW '11  
To bridge the gap, we propose Event Processing SPARQL (EP-SPARQL) as a new language for complex events and Stream Reasoning.  ...  We provide syntax and formal semantics of the language and devise an effective execution model for the proposed formalism.  ...  The operator allows information to be added to the answer where certain triples are available, but do not reject the answer when some part of the query pattern does not match.  ... 
doi:10.1145/1963405.1963495 dblp:conf/www/AnicicFRS11 fatcat:x3534wtrtbbmlfoyhrhgvv6ygq

Recursion in SPARQL

Juan Reutter, Adrián Soto, Domagoj Vrgoč, Oscar Corcho
2020 Semantic Web Journal  
This was acknowledged by the W3C committee by the inclusion of property paths in the SPARQL standard.  ...  We propose a rather different, but simpler approach: add a general purpose recursion operator directly to SPARQL.  ...  Acknowledgements This work was supported by the Millennium Institute for Foundational Research on Data (IMFD) and by CONICYT-PCHA Doctorado Nacional 2017-21171731.  ... 
doi:10.3233/sw-200401 fatcat:vjdpr3eguve6rasoqrqtkkz7ke

G-SPARQL

Sherif Sakr, Sameh Elnikety, Yuxiong He
2012 Proceedings of the 21st ACM international conference on Information and knowledge management - CIKM '12  
We propose a SPARQL-like language, G-SPARQL, for querying attributed graphs.  ...  We describe an algebraic compilation mechanism for our proposed query language which is extended from the relational algebra and based on the basic construct of building SPARQL queries, the Triple Pattern  ...  The TEDI indexing structure [46] has been proposed for answering shortest path queries.  ... 
doi:10.1145/2396761.2396806 dblp:conf/cikm/SakrEH12 fatcat:aeagal3dmzcu5meclzblkrlv3u

Recursion in SPARQL [chapter]

Juan L. Reutter, Adrián Soto, Domagoj Vrgoč
2015 Lecture Notes in Computer Science  
In this paper we propose a general purpose recursion operator to be added to SPARQL, formalize its syntax and develop algorithms for evaluating it in practical scenarios.  ...  This work was funded by the Millennium Nucleus Center for Semantic Web Research Grant NC120004. We would like to thank Aidan Hogan, Egor Kostylev, James Cheney and the reviewers for helpful comments.  ...  The answer ans(q, D) of q over D depends on the form of q: -If q is a SELECT query, then ans(q, D) is the answer to q as defined in the SPARQL standard [12] .  ... 
doi:10.1007/978-3-319-25007-6_2 fatcat:a464skqzm5bndcnfhqorpbqtpe

SPARQL beyond Subgraph Matching [chapter]

Birte Glimm, Markus Krötzsch
2010 Lecture Notes in Computer Science  
We extend the Semantic Web query language SPARQL by defining the semantics of SPARQL queries under the entailment regimes of RDF, RDFS, and OWL.  ...  The proposed extensions are part of the SPARQL 1.1 Entailment Regimes working draft which is currently being developed as part of the W3C standardization process of SPARQL 1.1.  ...  We thank the members of the SPARQL working group for valuable comments and suggestions.  ... 
doi:10.1007/978-3-642-17746-0_16 fatcat:qwwydaftwfavvapxlphvmpybri

Towards Reconciling SPARQL and Certain Answers

Shqiponja Ahmetaj, Wolfgang Fischl, Reinhard Pichler, Mantas Šimkus, Sebastian Skritek
2015 Proceedings of the 24th International Conference on World Wide Web - WWW '15  
The goal of this work is to introduce an intuitive certain answer semantics also for SPARQL and to show the feasibility of this approach.  ...  However, the semantics of query answering under SPARQL entailment regimes is defined in a more naive and much less expressive way than the certain answer semantics usually adopted in DLs.  ...  CERTAIN ANSWER SEMANTICS In this section, we propose an intuitive definition of certain answers for well-designed SPARQL queries or, more precisely, for pwdPTs.  ... 
doi:10.1145/2736277.2741636 dblp:conf/www/AhmetajFPSS15 fatcat:3f2254oh7jhqdf7lptvsjefyae

Certain Answers to a SPARQL Query over a Knowledge Base (extended version) [article]

Julien Corman, Guohui Xiao
2019 arXiv   pre-print
to capture both certain answers for UCQs and the standard interpretation of SPARQL over a plain graph.  ...  OMQA was originally designed for unions of conjunctive queries (UCQs), and based on certain answers.  ...  trying to define a suitable semantics for sparql that complies with certain answers for UCQs.  ... 
arXiv:1911.02668v3 fatcat:kcbw6khc6rd5hewcbtmcbw4apa

Bridging the Semantic Gap between RDF and SPARQL using Completeness Statements [Extended Version] [article]

Fariz Darari, Simon Razniewski, Werner Nutt
2014 arXiv   pre-print
In this paper, we address how to close the semantic gap between RDF and SPARQL in terms of certain answers and possible answers using completeness statements.  ...  This gives rise to a semantic gap between RDF and SPARQL.  ...  The result of a SPARQL query for Oscar winners with tattoos contains only all certain answers.  ... 
arXiv:1408.6395v2 fatcat:2jh47pzb2jgovmejba7g64ehy4

SPARQL Query Generation based on RDF Graph

Mohamed Kharrat, Anis Jedidi, Faiez Gargouri
2016 Proceedings of the 8th International Joint Conference on Knowledge Discovery, Knowledge Engineering and Knowledge Management  
., SPARQL) or knowledge based techniques. To simplify querying process, we introduce in this paper, a proposal of automatic SPARQL query generation based on user-supplied keywords.  ...  The construction of a SPARQL query is based on the top relevant RDF sub-graph, selected from our RDF Triplestore.  ...  Automatic query generation is one of them which has been integrated many times in certain solutions. In the following, we present recent works about SPARQL query generation.  ... 
doi:10.5220/0006091904500455 dblp:conf/ic3k/KharratJG16 fatcat:gckyvzkd4bfo5eif24y4tsuhh4

Extending SPARQL Algebra to Support Efficient Evaluation of Top-K SPARQL Queries [chapter]

Alessandro Bozzon, Emanuele Della Valle, Sara Magliacane
2012 Lecture Notes in Computer Science  
function for each solution, even if only a limited number (e.g.  ...  The new algebra and execution model allow for splitting the ranking function and interleaving it with other operations.  ...  avgRateProducer are certain bound variables, as the query contains no OPTIONAL or UNION clauses. The result of the evaluation is stored in the ?  ... 
doi:10.1007/978-3-642-34213-4_10 fatcat:l4v2yejsvnavfmljimpb2ovsja

Querying semantic web data with SPARQL

Marcelo Arenas, Jorge Pérez
2011 Proceedings of the 30th symposium on Principles of database systems of data - PODS '11  
Thus, one usually obtains partial answers when querying RDF with SPARQL, and the possibility of adding optional information if present is a crucial feature of SPARQL.  ...  RDF is the data model for Semantic Web data, and SPARQL is the standard query language for this data model.  ...  of certain answers that is properly characterized by the notion of weak monotonicity.  ... 
doi:10.1145/1989284.1989312 dblp:conf/pods/ArenasP11 fatcat:yfcudyqbb5fglet26ugkgcg4v4

SPARQL Query Answering over OWL Ontologies [chapter]

Ilianna Kollia, Birte Glimm, Ian Horrocks
2011 Lecture Notes in Computer Science  
The SPARQL query language is currently being extended by W3C with so-called entailment regimes, which define how queries are evaluated under more expressive semantics than SPARQL's standard simple entailment  ...  For standard conjunctive queries our system performs comparably to already deployed systems. For complex queries an improvement of up to three orders of magnitude can be observed.  ...  SPARQL-OWL Query Answering The SPARQL-OWL regime specifies what the answers are, but not how they can actually be computed.  ... 
doi:10.1007/978-3-642-21034-1_26 fatcat:zjxgdj6gj5cj5jkevi6oyiehgm

Learning to Transpile AMR into SPARQL [article]

Mihaela Bornea, Ramon Fernandez Astudillo, Tahira Naseem, Nandana Mihindukulasooriya, Ibrahim Abdelaziz, Pavan Kapanipathi, Radu Florian, Salim Roukos
2021 arXiv   pre-print
We propose a transition-based system to transpile Abstract Meaning Representation (AMR) into SPARQL for Knowledge Base Question Answering (KBQA).  ...  We departure from recent work relating AMR and SPARQL constructs, but rather than applying a set of rules, we teach the BART model to selectively use these relations.  ...  For exam- provides the gold answer directly.  ... 
arXiv:2112.07877v1 fatcat:ooyh4ysrurb7nltpc3jvx7djta
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