1 / 22

Search and Navigate Web Ontologies

Search and Navigate Web Ontologies. Li Ding Tetherless World Constellation Rensselaer Polytechnic Institute Aug 22, 2008. Outline. Background Enabling Search and Navigation Graph on Swoogle Enabling Collaborative Ontology Repository on Semantic Wikis. Online Ontology: Past and Future.

tamma
Download Presentation

Search and Navigate Web Ontologies

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Search and Navigate Web Ontologies Li Ding Tetherless World Constellation Rensselaer Polytechnic Institute Aug 22, 2008

  2. Outline • Background • Enabling Search and Navigation Graph on Swoogle • Enabling Collaborative Ontology Repository on Semantic Wikis

  3. Online Ontology: Past and Future • Pre-Web era (e.g. cyc, wordnet) • [semantics] define terms semantics, and interlink terms • [access] ontology available via local files, database, and KB • Now (e.g. foaf) • Increasing adoption of semantic web languages • [access] published and shared on the Web • Term identified by HTTP URI, support hyperlink • Web 3.0 era (e.g. tw.rpi.edu) • Native semantic web support • [semantics] preserve provenance information (history, author) • [access] collaboratively maintained on Semantic Wiki • Flexible ownership/edit granularity • Dynamic update and growth In what follows, we focus on semantic web ontolgoies

  4. SW Ontology: Conceptual Model SW Ontology http://xmlns.com/foaf/0.1/index.rdf rdfs:subClassOf class wordNet:Agent t1 foaf:Person rdf:type Meta Term t2 rdfs:Class SW Document t3 rdfs:domain foaf:mbox property rdf:type t4 rdf:Property Instance Data http://xmlns.com/foaf/0.1/ • SW Term Usage • Define class (t2) • Define property (t4) • Reference class (t1) • Reference property (t3) • Instantiate class (t5) • Instantiate property (t6) Namespace http://www.cs.rpi.edu/~dingl/foaf.rdf rdf:type foaf:Person t5 instance ex:Li t6 dingl@cs.rpi.edu foaf:mbox foaf:mbox

  5. Enabling Search and Navigation Graph (SNG) on Swoogle Online ontology is not merely a web page, so users need effective means to access ontology at different levels of granularity.

  6. Search and Navigation Graph: Without Search Engine Term description • Both term and ontology are navigation stops • Native semantic navigation (4,5,6,7), e.g. doc => term1 • Native Web navigation (1,2,3), e.g. onto1.t1 => onto2.t2 • Term lookup (match by name), e.g. fine concept person uses 6 7 Term lookup Meta Term Namespace string instantiates defines hyperlink 5 3 4 SW Document SW Ontology hyperlink 2 1 imports

  7. Example: Browsing Ontology and Terms in Ontology Editor

  8. What Else is Wanted? • Better search interface • How do I find terms related to “green tea” • How do I find documents related to “Li Ding” • More navigation paths • How to find instances of foaf:Person • How to find documents defining foaf:Person • Utilizing instance data • What class is frequently used as the domain of dc:title ?

  9. Example: Homepage of Term navigation paths Ranked description aggregation Surf to another term

  10. Search and Navigation Graph: Adding Keyword Search Term description 8 Term Search Semantically generate text metadata for term and ontology • Keyword search (8,9), e.g. keywords => term • Refined keyword search, e.g. prefix:keyword=> term uses 6 7 Meta Term Namespace lookup defines instantiates hyperlink 5 3 4 Keywords SW Document 9 SW Ontology Document Search hyperlink 2 1 imports

  11. Example: Term Search • Ontology search: search for a collection of concepts • Term search: search for one concept • Term search can support auto-completion via : label:agent Keyword search Results ranked by popularity label:  the lexeme of Term's local-name. e.g.  'SeaFood' has two labels: 'sea' and 'food' More term search options: http://swoogle.umbc.edu/index.php?option=com_swoogle_manual&manual=search_swt

  12. Search and Navigation Graph: Enriching Navigation Paths Term description, empirical relation 8 Term Search Use search engine metadata to improve navigation paths • Inverse navigation path (4,5,7), e.g. namespace => term • Empirical relation (6), e.g. dc:title => foaf:Person uses 6 7 Meta Term Namespace lookup defines instantiate hyperlink 4 5 3 Keywords SW Document 9 SW Ontology Document Search hyperlink 2 1 imports

  13. Example: Query based navigation • Navigate from class to documents containing instance data Query Docs By Term usage Meta usage

  14. Empirical Relations • May not be defined in ontology, e.g. FOAF uses rdfs:seeAlso • May be Inductively learned from instance data Onto 1 Onto 2 rdf:type owl:Class foaf:name foaf:Person rdfs:domain foaf:Agent foaf:Person rdfs:subClassOf foaf:name rdfs:domain rdf:type owl:Class wob:hasInstanceDomain foaf:Person wob:hasInstanceDomain foaf:Agent dc:title rdfs:subClassOf SWD3 foaf:name Tim Finin rdf:type foaf:Person dc:title Dr.

  15. Example: Empirical Navigation • I-domain (p2c): the listed terms have been instantiated (by doc_freq semantic web documents) as the domain of the specified term http://webns.net/mvcb/generatorAgent

  16. Summary: Enabling Search and Navigation Graph in Swoogle • Key technologies • Keyword search – natural language UI • Query based navigation – enrich navigation path • Ranking – promote reuse • Provenance – Each SNG node has an aggregated homepage, enable global view • Version cache – ensure permanency • Implementation highlights • 19 REST web services, implemented as JAVA servlet, outputs are in encoded in RDF (using WOB and SWOOGLE ontology) • Web interface (http://swoogle.umbc.edu), implemented using PHP, provide HTML interface for access web services and retrieve query results

  17. Enabling Collaborative Ontology Repository on Semantic Wikis Interestingly enough, the search and navigation graph (SNG) nicely fits the structure of Semantic Wikis

  18. Authoring Ontologies on Semantic Wiki • Wiki natively supports • Collaborative edit: user login, online editing • Provenance tracking: revision history, authors • Navigation: wiki-link, external-link, “what links here” • Semantic Wiki supports • HTML and RDF homepage for each term (class, property, instance) and ontology • RDFS inference, and potentially some OWL inference • Allow coexistence of ontology and instance • Conventional ontology editing UI via (i) template or (ii) semantic form + auto-completion

  19. Highlight 1: Wiki Homepage for Each Term and Ontology (SNG node)

  20. Concept Convergence One latest revision Multiple authors Dynamic concept may have many revisions Stable concept may be “Protected” Provenance in history Author Change date Changed content Change notes Highlight 2: Provenance Preserving Concept Convergence

  21. Highlight 3: Supporting Multiple Ontologies • Concpets from different ontologies may stay together and be connected

  22. Summary: Enabling Collaborative ontology repository on Semantic Wikis • Key technologies evaluation • Concept modeling – capable of RDFS, OWL, OBO storage • Keyword search - wiki native search is not enough • Navigation – absorb Swoogle technology • Ranking – absorb Swoogle technology • Provenance – add semantic history • Implementation highlights • http://tw.rpi.edu/ is an experimental work, which develops ontology for annotating instances • Semantic Mediawiki (SMW) and a selection of SMW extensions as the infrastructure • A set of wiki templates and semantic forms (in form of special wiki pages) for improving user interface

More Related