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Computing CQ lower-bounds over OWL 2 through approximation to RSA [article]

Federico Igne, Stefano Germano, Ian Horrocks
2021 arXiv   pre-print
We present a novel approximation of OWL 2 ontologies into RSA, and an algorithm to compute a closer (than PAGOdA) lower bound approximation using the RSA combined approach.  ...  The effectiveness of this approach critically depends on the quality of the approximations, and in this paper we explore a technique for computing closer approximations via RSA, an ontology language that  ...  (b) We use a novel algorithm to approximate the Horn-ALCHOIQ ontology to RSA (see Section 5). (c) We apply the RSA combined approach to obtain a lower-bound of the answers to the query.  ... 
arXiv:2107.00369v1 fatcat:avmr4bgxujfzll6ifcoavi4wiy

Expressivity of Planning with Horn Description Logic Ontologies (Technical Report) [article]

Stefan Borgwardt, Jörg Hoffmann, Alisa Kovtunova, Markus Krötzsch, Bernhard Nebel, Marcel Steinmetz
2022 arXiv   pre-print
We also provide a new rewritability result for the DL Horn-ALCHOIQ, which allows us to apply our compilation scheme to quite expressive ontologies.  ...  In contrast, we show that in the slight extension Horn-SROIQ no such compilation is possible unless the weak exponential hierarchy collapses.  ...  We continue by describing a novel polynomial Datalog ¬ -rewriting for queries in the very expressive DL Horn-ALCHOIQ (Ortiz, Rudolph, and Šimkus 2011) , which allows us to extend the previous compilability  ... 
arXiv:2203.09361v1 fatcat:gdgkyfuipjhk5dmbcr5bnc5lrm

Reasoning and Query Answering in Description Logics [chapter]

Magdalena Ortiz, Mantas Šimkus
2012 Lecture Notes in Computer Science  
horn , DL-Lite krom ) Queries in DLs The user can pose queries over the vocabulary of the ontology, the system performs reasoning to return all answers • Retrieve antibiotics that can be used to treat  ...  The Query Rewriting Approach -Example 1 TBox T : B B ∃S.  ...  the success of query rewriting and the combined approach, many challenges remain: The rewritten queries are often hard to evaluate • they can be very large (exponential blow-up in query size) • their  ... 
doi:10.1007/978-3-642-33158-9_1 fatcat:fzifcfpzwndgrng6jfjeldipxe

Ontologies and Data Management: A Brief Survey

Thomas Schneider, Mantas Šimkus
2020 Künstliche Intelligenz  
In order to align and complete data, systems may rely on taxonomies and background knowledge that are provided in the form of an ontology.  ...  Information systems have to deal with an increasing amount of data that is heterogeneous, unstructured, or incomplete.  ...  as you give appropriate credit to the original author(s) and the source,  ... 
doi:10.1007/s13218-020-00686-3 pmid:32999532 pmcid:PMC7497697 fatcat:zeskjfjrpvcojjh6q3yjzhlyci

Temporal Conjunctive Queries in Expressive Description Logics with Transitive Roles [chapter]

Franz Baader, Stefan Borgwardt, Marcel Lippmann
2015 Lecture Notes in Computer Science  
We extend the existing complexity analysis of TCQ entailment to very expressive DLs underlying the OWL 2 standard, and in contrast to previous work also allow for queries containing transitive roles.  ...  In order to deal with dynamically changing data sources, temporal conjunctive queries (TCQs) have recently been proposed as a useful extension of OBDA to support the processing of temporal information.  ...  For this reason, OBDA was extended to the temporal case in [1, 4] . In [4] the complexity of answering temporal conjunctive queries (TCQs) w.r.t.  ... 
doi:10.1007/978-3-319-26350-2_3 fatcat:vgny3kj7qjftxn66yj5by3l5zy

From Horn-SRIQ to Datalog: A Data-Independent Transformation That Preserves Assertion Entailment

David Carral, Larry González, Patrick Koopmann
2019 PROCEEDINGS OF THE THIRTIETH AAAI CONFERENCE ON ARTIFICIAL INTELLIGENCE AND THE TWENTY-EIGHTH INNOVATIVE APPLICATIONS OF ARTIFICIAL INTELLIGENCE CONFERENCE  
To access data efficiently, one approach is to rewrite the ontology into Datalog, and then use powerful Datalog engines to compute implicit entailments.  ...  We go one step further and present one such data-independent rewriting technique for Horn-SRIQ⊓, the extension of Horn-SHIQ that supports role chain axioms, an expressive feature prominently used in many  ...  Acknowledgements We thank Irina Dragoste for assisting us with the execution of the experiments, for which we used the servers from the Centre for Information Services and High Performance Computing (ZIH  ... 
doi:10.1609/aaai.v33i01.33012736 fatcat:7ozaadq5rzfthn56apkgwwjqya

Reasoning over Ontologies with Hidden Content: The Import-by-Query Approach

B. Cuenca Grau, B. Motik
2012 The Journal of Artificial Intelligence Research  
In particular, we outline the limitations of our framework and prove that certain restrictions on the expressivity of Kh and the way in which Kv reuses symbols from Kh are strictly necessary to enable  ...  Towards this goal, in this paper we propose the import-by-query framework, which makes the content of Kh accessible through a limited query interface.  ...  Acknowledgments This is an extended version of the paper "Import-by-Query: Ontology Reasoning under Access Limitations" by Bernardo Cuenca Grau, Boris Motik, and Yevgeny Kazakov published at IJCAI 2009  ... 
doi:10.1613/jair.3579 fatcat:bpo4eakk7fa6fmzvadi3ulwewq

A Modal Logic for Joint Abilities under Strategy Commitments

Zhaoshuai Liu, Liping Xiong, Yongmei Liu, Yves Lespérance, Ronghai Xu, Hongyi Shi
2020 Proceedings of the Twenty-Ninth International Joint Conference on Artificial Intelligence  
However, most of the logical frameworks ignore the issue of coordination within a coalition, and are unable to specify the internal structure of strategies.  ...  Secondly, our logic is based on linear dynamic logic (LDL), an extension of linear temporal logic (LTL), so that we can use regular expressions to represent commitments to structured strategies.  ...  Proceedings of the Twenty-Ninth International Joint Conference on Artificial Intelligence  ... 
doi:10.24963/ijcai.2020/246 dblp:conf/ijcai/CarralK20 fatcat:biobkota7fgr7ccnediiu2e45a

Using Ontology-Based Data Access to Enable Context Recognition in the Presence of Incomplete Information

Veronika Thost
2017 Künstliche Intelligenz  
Systems for OBDA thus may apply logical reasoning to answer queries; they use the ontological knowledge to infer new information, which is only implicitly given in the data.  ...  In particular, we study the computational complexity of temporal query answering regarding ontologies written in lightweight description logics, which are known to allow for efficient reasoning in the  ...  , Thm. 9] DL-Lite horn PEQ [Kon+11, Thm. 3] DL-Lite R C2RPQ [BOS15, Lem. 3.2] Horn-ALCHIQ CQ [Eit+12, Thm. 3], [Kaz09] Horn-ALCHOIQ Disj Self Th. 5.18, ≤ Co. 5.17 Data Complexity Combined  ... 
doi:10.1007/s13218-017-0510-z fatcat:uozqpml73rg55plkicfyofq3hq

$\mathcal{EL}$ -ifying Ontologies [chapter]

David Carral, Cristina Feier, Bernardo Cuenca Grau, Pascal Hitzler, Ian Horrocks
2014 Lecture Notes in Computer Science  
The OWL 2 profiles are fragments of the ontology language OWL 2 for which standard reasoning tasks are feasible in polynomial time.  ...  It works in two steps: a preprocessing step where the ontology is brought into a normal form, and a rewriting step, where the normalised ontology is "EL-ified". Theorem 2. Let K = Ξ(K).  ...  It follows from Theorem 7 that the technique in [22] leads to exact answers to atomic queries for Horn ontologies where all roles are reuse-safe.  ... 
doi:10.1007/978-3-319-08587-6_36 fatcat:5qft5q2zzjhlpgiyqr3nuaqngq

Polynomial Datalog Rewritings for Expressive Description Logics with Closed Predicates

Shqiponja Ahmetaj, Magdalena Ortiz, Mantas Šimkus
2019 Artificial Intelligence  
In this way we can retrieve more precise answers to queries by leveraging the partial completeness of the data.  ...  Our main result is to show that every query in this non-monotonic query language can be translated in polynomial time into Datalog with negation under the stable model semantics.  ...  Acknowledgments This work was supported by the Austrian Science Fund (FWF) projects P30360, P30873, and W1255-N23.  ... 
doi:10.1016/j.artint.2019.103220 fatcat:ac3pgrnvfvds5l33sfp2h2rehi

Representing ontologies using description logics, description graphs, and rules

Boris Motik, Bernardo Cuenca Grau, Ian Horrocks, Ulrike Sattler
2009 Artificial Intelligence  
Furthermore, to enable modeling the conditional aspects of structured objects, we also extend DLs with rules. We present an in-depth study of the computational properties of such a formalism.  ...  In particular, we first identify the sources of undecidability of the general, unrestricted formalism.  ...  Consequently, such extensions are useful mainly for query answering, but not for schema modeling.  ... 
doi:10.1016/j.artint.2009.06.003 fatcat:p6fot546bjfqvojbefxxc7x45e