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CKR - Contextualized Knowledge Repository
The Contextualized Knowledge Repository (CKR) is a knowledge representation and reasoning framework that build on Semantic Web technologies to represent, store, query and reason with contextualized knowledge, i.e. knowledge that holds under specific circumstances or contexts. The CKR addresses an arising needs in the Semantic Web, where as large amounts of Linked Data are published on the Web, it is becoming apparent that the validity of published knowledge is not absolute, but often depends on time, location, topic, and other contextual attributes.
- intuitive context representation based on the context-as-a-box principle: contexts are treated as small and inter-related knowledge bases qualified along contextual dimensions such as time, space and topic;
- context structuring along a broader-narrower hierarchy, automatically induced by the qualification of contexts along dimensions and by the structuring of dimensional values;
- cross-context statements to relate knowledge in different contexts, based on 'qualified symbols';
- contextual reasoning based on OWL 2 RL local reasoning inside contexts and knowledge propagation rules across contexts, with support of 'CKR closure' to precompute and materialize all inferrable stetaments;
- SPARQL-based contextual queries, supporting the constraining and the extraction of knowledge from multiple contexts by extending SPARQL with a CONTEXT keyword;
- well defined semantics rooted in established AI principia for contextualized knowledge representation;
- standard-friendly as rooted in Semantic Web standards as RDF, OWL 2 and Named Graphs.
CKR on SPRINGLES
Implementation of CKR defined as SPARQL-based forward rules over multiple RDF named graphs. The framework is implemented over an extension of Sesame called SPRINGLES (SParql-based Rule Inference over Named Graphs Layer Extending Sesame), which supports the specification and execution of inference over Sesame RDF repositories.
Download and demo (DL2013): https://dkm.fbk.eu/ckr-tourismdemo
Reference paper: DL2013
CKRew - CKR datalog rewriter
CKRew provides a datalog translation of OWL2-RL based CKR and supports reasoning with global defeasible axioms (or justifiable exceptions). CKRew is implemented as an extension of the DL to datalog rewriter DReW. and provides a command line utility for the translation of CKRs represented as RDF/TRIG files.
Reference paper: DL2014
First implementation of the framework, developed in the context of the LiveMemories project. The prototype implements CKR for OWL2-RL/RDFS(S) data on top of the Sesame and OWLIM frameworks, and supports storing, reasoning and querying with contextual knowledge.
Prototype and evaluation page: https://dkm.fbk.eu/technologies/ckr-prototype
- Martin Homola, Luciano Serafini Contextualized knowledge repositories for the Semantic Web in Journal of Web Semantics vol. 12, 2012 (paper)
Conference and workshop papers:
- Loris Bozzato, Stefano Borgo, Alessio Palmero Aprosio, Marco Rospocher, Luciano Serafini A Contextual Framework for Reasoning on Events in 4th International Workshop on Detection, Representation,and Exploitation of Events in the Semantic Web (DeRiVE), 2015 (paper)
- Loris Bozzato, Luciano Serafini Knowledge Propagation in Contextualized Knowledge Repositories: an Experimental Evaluation (extended paper) in 19th International Conference on Knowledge Engineering and Knowledge Management (EKAW), 2014 (paper)
- Loris Bozzato, Luciano Serafini Knowledge Propagation in Contextualized Knowledge Repositories: an Experimental Evaluation in 6th Int. Workshop on Acquisition, Representation and Reasoning with Contextualized Knowledge (ARCOE-LogIC), 2014 (paper)
- Loris Bozzato, Thomas Eiter, Luciano Serafini Contextualized Knowledge Repositories with Justifiable Exceptions in 27th Workshop on Description Logics, 2014 (paper)
- Loris Bozzato, Thomas Eiter, Luciano Serafini Defeasibility in contextual reasoning with CKR in 29mo Convegno Italiano di Logica Computazionale (CILC), 2014 (paper)
- Loris Bozzato, Martin Homola, Luciano Serafini ExpTime Tableaux Algorithm for Contextualized ALC in 8th Int. Conference on Modeling and Using Context (CONTEXT), 2013 (paper)
- Loris Bozzato, Thomas Eiter, Luciano Serafini Defeasibility in contextual reasoning with CKR in 5th Int. Workshop on Acquisition, Representation and Reasoning with Contextualized Knowledge (ARCOE-LogIC), 2013 (notes)
- Loris Bozzato, Chiara Ghidini, Luciano Serafini Comparing contextual and flat representations of knowledge – a concrete case about football data in 7th Int. Conference on Knowledge Capture (K-CAP), 2013 (paper)
- Loris Bozzato, Luciano Serafini Materialization Calculus for Contexts in the Semantic Web in 26th Int. Workshop on Description Logics, 2013 (paper)
- Loris Bozzato, Martin Homola, Luciano Serafini Towards More Effective Tableaux Reasoning for CKR in 25th Workshop on Description Logics, 2012 (paper | slides)
- Martin Homola, Luciano Serafini Contextual representation and reasoning with description logics in 24th Workshop on Description Logics, 2011 (paper)
- Mathew Joseph, Luciano Serafini Simple reasoning for contextualized RDF knowledge in 5th Workshop on Modular Ontologies (WoMo), 2011 (preprint)
- Martin Homola, Andrei Tamilin, Luciano Serafini Modeling contextualized knowledge in 2nd Workshop on Context, Information and Ontologies (CIAO), 2010 (paper)
- Andrei Tamilin, Bernardo Magnini, Luciano Serafini, Christian Girardi, Mathew Joseph, Roberto Zanoli Context-Driven Semantic Enrichment of Italian News Archive in 7th Extended Semantic Web Conference (ESWC), 2010 (paper)
- Andrei Tamilin, Bernardo Magnini, Luciano Serafini Leveraging Entity Linking by Contextualized Background Knowledge: A case study for news domain in Italian in 6th Workshop on Semantic Web Applications and Perspectives (SWAP), 2010 (paper)
- Loris Bozzato, Martin Homola, Luciano Serafini ExpTime Reasoning for Contextualized ALC TR-FBK-DKM-2012-1
- Loris Bozzato, Martin Homola, Luciano Serafini Evaluation of Contextual Modelling in the FIFA World Cup Use Case TR-FBK-DKM-2011-3
- Loris Bozzato, Mathew Joseph, Luciano Serafini Evaluation of contextual queries TR-FBK-DKM-2011-2
- Martin Homola, Loris Bozzato, Luciano Serafini Tableaux Algorithm for Reasoning with Contextualized Knowledge TR-FBK-DKM-2011-1
- Loris Bozzato, Martin Homola, Mathew Joseph, Luciano Serafini Managing Contextualized Knowledge with the CKR in 9th Extended Semantic Web Conference (ESWC), Heraklion, Crete, Greece, 2012 (paper)
- Initial development of the CKR was supported by the LiveMemories project (Active Digital Memories of Collective Life) aimed at developing methods for automatically interpreting the content of unrelated digital fragments and multimedia data of different nature and provenance, and transforming them into "active memories".
- CKR has been lately applied in the Toolisse project for the development of a unified service platform for digital tourism.
- CKR research has been applied and was supported by the PlanetData European Network of Excellence.