Search Results for author: Guohui Xiao

Found 7 papers, 1 papers with code

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

no code implementations6 Nov 2019 Julien Corman, Guohui Xiao

More recently, OMQA has been extended to SPARQL queries, but to our knowledge, none of the efforts made in this direction (either in the literature, or the so-called SPARQL entailment regimes) is able to capture both certain answers for UCQs and the standard interpretation of SPARQL over a plain graph.

Enriching Ontology-based Data Access with Provenance (Extended Version)

no code implementations1 Jun 2019 Diego Calvanese, Davide Lanti, Ana Ozaki, Rafael Penaloza, Guohui Xiao

In particular, we investigate the problems of (i) deciding whether a provenance annotated OBDA instance entails a provenance annotated conjunctive query, and (ii) computing a polynomial representing the provenance of a query entailed by a provenance annotated OBDA instance.

BigSR: an empirical study of real-time expressive RDF stream reasoning on modern Big Data platforms

no code implementations12 Apr 2018 Xiangnan Ren, Olivier Curé, Hubert Naacke, Guohui Xiao

The trade-off between language expressiveness and system scalability (E&S) is a well-known problem in RDF stream reasoning.

Distributed Computing

Data Scaling in OBDA Benchmarks: The VIG Approach

1 code implementation21 Jul 2016 Davide Lanti, Guohui Xiao, Diego Calvanese

The advantage of the approach is that the user is not required to manually input the characteristics of the data to be produced, making it particularly suitable for OBDA benchmarks, where the complexity of database schemas might pose a challenge for manual input (e. g., the NPD benchmark contains 70 tables with some containing more than 60 columns).

Databases

OBDA Constraints for Effective Query Answering (Extended Version)

no code implementations13 May 2016 Dag Hovland, Davide Lanti, Martin Rezk, Guohui Xiao

In Ontology Based Data Access (OBDA) users pose SPARQL queries over an ontology that lies on top of relational datasources.

Translation

Beyond OWL 2 QL in OBDA: Rewritings and Approximations (Extended Version)

no code implementations26 Nov 2015 Elena Botoeva, Diego Calvanese, Valerio Santarelli, Domenico Fabio Savo, Alessandro Solimando, Guohui Xiao

Ontology-based data access (OBDA) is a novel paradigm facilitating access to relational data, realized by linking data sources to an ontology by means of declarative mappings.

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