Oliver Kutz & Christoph Lange Research Center on Spatial Cognition (SFB/TR 8), University of Bremen, Germany & Jacobs University Bremen, Germany Joint work with Till Mossakowski (DFKI)- Christian Galinski (Infoterm) Seoul, South Korea - LaRC, June 2011
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Towards a Standard for Heterogeneous Ontology Integration and Interoperability Oliver Kutz & Christoph Lange Research Center on Spatial Cognition (SFB/TR.
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Towards a Standard for Heterogeneous Ontology
Integration and Interoperability
Oliver Kutz & Christoph LangeResearch Center on Spatial Cognition (SFB/TR 8), University of Bremen,
Germany& Jacobs University Bremen, Germany
Joint work with
Till Mossakowski (DFKI)- Christian Galinski (Infoterm)
Seoul, South Korea - LaRC, June 2011
Ontology Interoperability• Critical issues are
• Semantic Heterogeneity
• Syntactic Heterogeneity
• Plurality of structuring & modularity concepts
• Plurality of documentation techniques
• Plurality of tools, editors, reasoners, etc.
• Plurality of (kinds of) services, devices, etc.
Overview• Motivating Examples for the use of the hyperontology framework
• Structured Ontology Design
• Matching in networks of ontologies
• Relations between ontologies: Refinements, Blending, etc.
• Universal logic addresses (onto)-logical pluralism and semantic heterogeneity
• Hyperontologies = structured and heterogeneous (networks of) ontologies
• A Sketch of a future standard: DOL: Distributed Ontology Language
Structured Ontologies
Dolce’s structuringin CASL, showing the import structure, i.e. the modular re-use
Matching Across Repositories• Ontology Repositories, e.g.
BioPortal, Orate, Colore, Tones: collections of ontologies for different purposes and in various ontology languages.
• create new ones out of existing ones by finding synonyms, extracting modules, and merging them together.
• Meaning shift and “chinese whispers”.
• problem of heterogeneity & scalability
• problem of “information overflow”
Heterogeneous Refinement of Dolce
• Different version of Dolce are available, e.g. in DL and FOL: What is their logical relationship?
Core
Projection
Approximation
heterogeneous refinement
definitional extension
connection through bridge theory
P(x)Q(x,y)
P(x)Q(x,y)
R(x) R(x,t)
R(x,t) ∼ R(x)(forget temporal
dimension)
S(x,y,z)
U(x,y)V(z)...
Dolce-LITE Dolce-FOL
Ontological Blending
Selectively combining two ontologies whilst preserving common structure (theory).
Motivation:Conceptual Blending and metaphor:
House + Boat = Houseboat Boat + House = Boatshouse
Pluralism in Ontologies• NCI Thesaurus
about 34.000 concepts arranged in 20 taxonomic trees, reference terminology for cancer research, sub-Boolean description logic EL.
• Galenmedical domain ontology, relatively large, but also relatively complex axiomatisation in a more expressive DL, namely OWL-DL.
• Models: possible world; domains of discourse; accessibility (counterpart relations) ; object (individual)
• Satisfaction: vary the truth conditions for quantifiers; Booleans; Modalities; vary conditions for identity statements, etc.
Items that can be varied according to universal logic:
Benefits: Borrowing and combination of logics and reasoners, structuring, etc.
Heterogeneous Ontologies• In order to systematically link
and combine ontological modules formulated in different formalisms we need to:
• fix a logic graph
• give logic translations (institution co-morphisms)
Onto-Logical Translation Graph
Hyperontology example
Heterogeneous specification of
Mereology
A hyperontology is a heterogeneously interlinked network of
heterogeneous ontology modules.
Hyperontologies via Matching• 5 participating ontologies, all
connected via matchings.
• matching results in a single synset identifying all matched concepts, and inconsistency.
• removal of the Graphics ontology can cut synset into 2 distinct ones, can restore consistency.
• following more than one orange arrow means playing chinese whispers.
O1 O3
O2 O4
O5
The Problem of Module Extraction• JRAO is constructed using fragments of NCI and Galen
• NCI, Galen are too large to be imported completely
• Import only interesting ‘modules’
• Conservativity:Ensure that the ‘module’ is large enough to cover all relevant information (coverage)Ensure that no new information is added (safety)Add only relevant axioms (minimality)
produce formal produce formal specificationspecification
ModulesModules
Merged Merged OntologyOntology
consistenconsistency checkcy check
UserUser
yes
no
extract extract modulesmodules
match match pairwisepairwise
compute compute colimitcolimit
Hets - The Heterogeneous Tool Set• structured
representations (such as V-alignments), reuse/independent development of modules
• library of logics/formalisms supported, incl. OWL-DL
• various provers connected: incl. for OWL-DL, first-order, higher-order, model checker, etc
• computation of colimits
• checking for conservativities
DOL - Distributed Ontology Language
• general purpose framework for ontology interoperabilitylibrary of logics/formalisms supported, incl. most ontology languages
• well-defined formal semanticspairs of languages have common target ontology languageApplication T(O) of translation to ontology part of DOL syntax
• DIF: XML- and RDF-based interchange formats Mapping two ontology
languages into a third
DOL - Distributed Ontology Language
Mapping two ontology languages into a third
• support for various module languages as well as one universal lingua francaexplicit module extractioninternalise ontology mappings (first class citizens)make ontology translations available in the language
• distributed ontologies in terms of both
• different internet locations and
• different ontology languages.
Embedded Ontology Documentation
• … but also for human users of an ontology (make ontologies comprehensible)
• Knowledge Engineers and Service Developers – reuse!
• End Users – when services expose ontology documentation (“labels” and more) as online help
Ontological Structuring and Modularity is not only for machines …
Documentation State of the Art
• SKOS (Simple Knowledge Organization System): an OWL ontology with some non-OWL axioms
• “documented” in HTML manual, and unstructured source comments
Language Documentation Support
Documentation Features Unsupported so far
• Informal subsets of an ontology (not yet explicitly modularized)
• Subterms of complex axioms
• Literate Programming:natural language and formal expressions freely interwoven ⇒ generate ontology and manual from same source
Documentation in DOL• Use existing annotation facilities where possible