Filters








350 Hits in 4.3 sec

Absorption for ABoxes

Jiewen Wu, Alexander Hudek, David Toman, Grant Weddell
2014 Journal of automated reasoning  
We also report on the results of a preliminary experimental evaluation that validates the efficacy of the method.  ...  We present a novel method of evaluating instance queries over description logic knowledge bases that derives from binary absorption.  ...  by each query over these datasets.  ... 
doi:10.1007/s10817-014-9304-2 fatcat:4zoa6huvqbhcjfl3hmcpfizy2q

Putting ABox Updates into Action [chapter]

Conrad Drescher, Hongkai Liu, Franz Baader, Steffen Guhlemann, Uwe Petersohn, Peter Steinke, Michael Thielscher
2009 Lecture Notes in Computer Science  
Second, iterated update operations result in very large Boolean ABoxes, which, however, contain a huge amount of redundant information.  ...  In this paper, we address both issues from a practical point of view.  ...  Acknowledgments: Many thanks to Albert Oliveras for his help regarding the construction of a backjump clause in the DPLL(T) approach.  ... 
doi:10.1007/978-3-642-04222-5_13 fatcat:fzjncmj3wvakvip2hxix76hvxe

Temporal Minimal-World Semantics for Sparse ABoxes [article]

Stefan Borgwardt, Walter Forkel, Alisa Kovtunova
2021 arXiv   pre-print
Our contribution consists of two main parts: In the first part we introduce a new closed-world semantics for answering conjunctive queries with negation over ontologies formulated in the description logic  ...  Ontology-mediated query answering is a popular paradigm for enriching answers to user queries with background knowledge.  ...  Preliminaries We recall the definitions of ELH and first-order queries, which are needed for our rewriting of conjunctive queries with negation. The Description Logic ELH .  ... 
arXiv:2105.14369v1 fatcat:m7yjfon6afcppefsdaxex3isfy

Extract ABox Modules for Efficient Ontology Querying [article]

Jia Xu, Patrick Shironoshita, Ubbo Visser, Nigel John, Mansur Kabuka
2014 arXiv   pre-print
The extraction of logically-independent fragments out of an ontology ABox can be useful for solving the tractability problem of querying ontologies with large ABoxes.  ...  In this paper, we propose a formal definition of an ABox module, such that it guarantees complete preservation of facts about a given set of individuals, and thus can be reasoned independently w.r.t. the  ...  or arbitrary property assertion checking (i.e. test if K |= R(a, b)), or when performing instance retrieval and answering (conjunctive) queries over ontologies (Horrocks and Tessaris, 2000; Glimm et  ... 
arXiv:1305.4859v4 fatcat:tnwzdbx4srextfn26aiuj766oi

Temporal Minimal-World Query Answering over Sparse ABoxes

STEFAN BORGWARDT, WALTER FORKEL, ALISA KOVTUNOVA
2021 Theory and Practice of Logic Programming  
Our contribution consists of two main parts: In the first part, we introduce a new closed-world semantics for answering conjunctive queries (CQs) with negation over ontologies formulated in the description  ...  Ontology-mediated query answering is a popular paradigm for enriching answers to user queries with background knowledge.  ...  Temporal Minimal-World Semantics for Sparse ABoxes 7 A conjunctive query (CQ) q(x) is a first-order query of the form ∃y. ϕ(x, y), where ϕ is a conjunction of atoms.  ... 
doi:10.1017/s1471068421000119 fatcat:zbto6slcqjd3vaew3quipqgaka

A Comparison of Reasoning Techniques for Querying Large Description Logic ABoxes [chapter]

Boris Motik, Ulrike Sattler
2006 Lecture Notes in Computer Science  
Many modern applications of description logics (DLs) require answering queries over large data quantities, structured according to relatively simple ontologies.  ...  Hence, in our previous work, we developed an algorithm for reducing a DL knowledge base to a disjunctive datalog program.  ...  Whereas some applications rely on reasoning over large TBoxes, many DL applications involve answering queries over knowledge bases with small and simple TBoxes, but with large ABoxes.  ... 
doi:10.1007/11916277_16 fatcat:qs7odntjyzeephcg7la5gnigbi

ABox Abduction in the Description Logic $\boldsymbol{\mathcal{ALC}}$

Szymon Klarman, Ulle Endriss, Stefan Schlobach
2010 Journal of automated reasoning  
In this paper we introduce two novel reasoning calculi for solving ABox abduction problems in the Description Logic ALC, i.e. problems of finding minimal sets of ABox axioms, which when added to the knowledge  ...  base enforce entailment of a requested set of assertions.  ...  Conclusions ABox abduction is a particularly interesting form of abductive reasoning over DL ontologies.  ... 
doi:10.1007/s10817-010-9168-z fatcat:kvdnqqzsinhbliwmqree3wcgfa

Compiling Model Representations for Querying Large ABoxes in Expressive DLs

Labinot Bajraktari, Magdalena Ortiz, Mantas Simkus
2018 Proceedings of the Twenty-Seventh International Joint Conference on Artificial Intelligence  
To illustrate the potential of our approach for OMQ answering, we implement a rewriting into an extension of Datalog for OMQs comprising reachability queries, and provide some promising evaluation results  ...  Towards narrowing the gap, we propose an algorithm to compile a representation of sets of models for ALCHI ontologies, which is sufficient for answering any monotone OMQ.  ...  The average answer time over all of them is reported in the table.  ... 
doi:10.24963/ijcai.2018/234 dblp:conf/ijcai/BajraktariOS18 fatcat:imixtjrwmvd27ntv3ypcogyzre

Parallel ABox Reasoning of ${\mathcal{EL}}$ Ontologies [chapter]

Yuan Ren, Jeff Z. Pan, Kevin Lee
2012 Lecture Notes in Computer Science  
Our evaluation shows that a naive implementation of our approach can compute all ABox entailments of a Not-Galen − ontology with about 1 million individuals and 9 million axioms in about 3 minutes.  ...  In this paper, we extend a parallel TBox reasoning algorithm for ELHR+ to a parallel ABox reasoning algorithm for ELH ⊥,R+ , which also supports the bottom concept so as to model disjointness and inconsistency  ...  Such results can be very useful for efficient on-line instance retrieval and/or query answering.  ... 
doi:10.1007/978-3-642-29923-0_2 fatcat:byxgvt232rft7kgwbarp4bu53u

Module Extraction for Efficient Object Queries over Ontologies with Large ABoxes

Jia Xu, Patrick Shironoshita, Ubbo Visser, Nigel John, Mansur Kabuka
2015 Artificial Intelligence and Applications  
The extraction of logically-independent fragments out of an ontology ABox can be useful for solving the tractability problem of querying ontologies with large ABoxes.  ...  In this paper, we propose a formal definition of an ABox module, such that it guarantees complete preservation of facts about a given set of individuals, and thus can be reasoned independently w.r.t. the  ...  or arbitrary property assertion checking (i.e. test if K |= R(a, b)), or when performing instance retrieval and answering (conjunctive) queries over ontologies [14, 16] .  ... 
doi:10.15764/aia.2015.01002 pmid:26848490 pmcid:PMC4736732 fatcat:hd4otptoffauzhdgg7ees3b4um

Data complexity of query answering in description logics

Diego Calvanese, Giuseppe De Giacomo, Domenico Lembo, Maurizio Lenzerini, Riccardo Rosati
2013 Artificial Intelligence  
In this paper we study data complexity of answering conjunctive queries over Description Logic knowledge bases constituted by an ABox and a TBox.  ...  FOL-reducibility means that query answering can be reduced to evaluating queries over the database corresponding to the ABox.  ...  Lemma 6 Let T be a DL-Lite R TBox, q a conjunctive query of arity n over T , and let A be an ABox.  ... 
doi:10.1016/j.artint.2012.10.003 fatcat:yulvaclpwzhwhp7cv3mwbc7enu

View-based query answering in Description Logics: Semantics and complexity

Diego Calvanese, Giuseppe De Giacomo, Maurizio Lenzerini, Riccardo Rosati
2012 Journal of computer and system sciences (Print)  
certain answers over an ontology.  ...  In this article, we present a first study on view-based query answering in DL ontologies.  ...  In what follows, when we talk about query answering (with and without UNA, respectively) in a DL ontology K, we mean computing the certain answers to a conjunctive query over K (with and without UNA, respectively  ... 
doi:10.1016/j.jcss.2011.02.011 fatcat:edprmlempnfnbk5xrvpmcz7y6i

Prexto: Query Rewriting under Extensional Constraints in DL − Lite [chapter]

Riccardo Rosati
2012 Lecture Notes in Computer Science  
In this paper we present Prexto, an algorithm for computing a perfect rewriting of unions of conjunctive queries over ontologies expressed in the description logic DL-LiteA.  ...  We show that these optimizations allow Prexto to outperform the existing query rewriting techniques for DL-Lite in practical cases.  ...  The distinguishing feature of DL-Lite is to identify ontology languages in which expressive queries, in particular, unions of conjunctive queries (UCQs), over the ontology can be efficiently answered.  ... 
doi:10.1007/978-3-642-30284-8_31 fatcat:yzebqqmbqzf3jhe3ug72ydz62e

Converting Instance Checking to Subsumption: A Rethink for Object Queries over Practical Ontologies

Jia Xu, Patrick Shironoshita, Ubbo Visser, Nigel John, Mansur Kabuka
2015 International Journal of Intelligence Science  
Considered as a basic service for answering object queries over DL ontologies, instance checking can be realized by using the most specific concept (MSC) method, which converts instance checking into subsumption  ...  In this paper, we propose a revision to this MSC method for DL SHI, allowing it to generate much simpler and smaller concepts that are specific-enough to answer a given query.  ...  It can be particularly useful for answering object queries over those large non-Horn DL ontologies, where existing optimization techniques may fall short and answering object queries may demand thousands  ... 
doi:10.4236/ijis.2015.51005 pmid:26594595 pmcid:PMC4652860 fatcat:v7qmu4nft5d25e56cbp2hvbz34

Towards a Unifying Approach to Representing and Querying Temporal Data in Description Logics [chapter]

Víctor Gutiérrez-Basulto, Szymon Klarman
2012 Lecture Notes in Computer Science  
The difficulty lies in that a proposed approach should reconcile a number of valuable contributions coming from diverse, yet relevant research lines, such as temporal databases and query answering in DLs  ...  Further, we advocate a controlled use of epistemic semantics in order to warrant practical query answering.  ...  Let ψ be a T QL query over a temporal ABox A T w.r.t. TBox T , where ABox and TBox axioms are expressed in a DL language L.  ... 
doi:10.1007/978-3-642-33203-6_8 fatcat:2np2ygklbfh73awl5gu2ycze44
« Previous Showing results 1 — 15 out of 350 results