Ontologies and the Semantic Web SMBM-2006 Jena, April 9, 2006 Steffen Staab http://isweb.uni-koblenz.de Steffen Staab (1) ISWeb – Informationssysteme & Semantic Web Agenda 1. Ontologies 2. Semantic Web 3. Semantic Web Languages 4. Some Applications (Ontoprise) 5. Ontologies & Text Steffen Staab (2) ISWeb – Informationssysteme & Semantic Web Part I Introduction to Ontologies Steffen Staab (3) ISWeb – Informationssysteme & Semantic Web Origin and History • Ontology in Philosophy • a philosophical discipline, branch of philosophy that deals with the nature and the organization of reality • Science of Being (Aristotle, Metaphysics, IV, 1) • Tries to answer the questions: • What characterizes being? • Eventually, what is being? Steffen Staab (4) ISWeb – Informationssysteme & Semantic Web Aristotle - Ontology • Before: study of the nature of being • Since Aristotle: study of knowledge representation and reasoning • Terminology: – Genus: (Classes) – Species: (Subclasses) – Differentiae: (Characteristics which allow to group or distinguish objects from each other) • Syllogisms (Inference Rules) Steffen Staab (5) ISWeb – Informationssysteme & Semantic Web Example for differentiae (adapted from Uta Priss, in preparation) real cartoon cat dog rabbit fish gorilla koala mammal Garfield X X X Snoopy X X X Bugs X X X Bunny Nemo X X Copito X X X Osmond X X X Steffen Staab (6) ISWeb – Informationssysteme & Semantic Web Organizing the Objects as a Lattice Steffen Staab (7) ISWeb – Informationssysteme & Semantic Web What is an Ontology? Gruber 93: An Ontology is a formal specification ⇒ Executable, Discussable of a shared ⇒ Group of persons conceptualization ⇒ About concepts of a domain of interest ⇒ Between application and „unique truth“ Steffen Staab (8) ISWeb – Informationssysteme & Semantic Web Why Develop an Ontology? • To make domain assumptions explicit – Easier to change domain assumptions – Easier to understand and update legacy data • To separate domain knowledge from operational knowledge – Re-use domain and operational knowledge separately •A community reference for applications •To share a consistent understanding of what information means Steffen Staab (9) ISWeb – Informationssysteme & Semantic Web Menu Taxonomy Object Person Topic Document Student Researcher Semantics Doctoral Student PhD Student F-Logic Ontology Taxonomy := Segmentation, classification and ordering of elements into a classification system according to their relationships between each other Steffen Staab (10) ISWeb – Informationssysteme & Semantic Web Menu Thesaurus Object Person Topic Document Student Researcher Semantics Doktoral Student PhD Student F-Logic Ontology synonym similar • Terminology for specific domain • Taxonomy plus fixed relationships (similar, synonym, related to) • originate from bibliography Steffen Staab (11) ISWeb – Informationssysteme & Semantic Web Menu Topic Map Object knows described_in Person Topic Document writes Student Researcher Semantics Doktoral Student PhD Student F-Logic Ontology synonym similar Tel Affiliation • Topics (nodes), relationships and occurences (to documents) • ISO-Standard • typically for navigation- and visualisation Steffen Staab (12) ISWeb – Informationssysteme & Semantic Web Ontology (in our sense) Object is_a-1 knows described_in Person Topic Document writes is_a-1 Student Researcher Semantics F-Logic Ontology is_a-1 subTopicOf similar Affiliation DoktoralPhDPhD Student Student Student PhD Student F-Logic Ontology Rules instance_of-1 T described_insimilar D T is_about D Tel Affiliation York Sure P writes D is_about T P knows T +49 721 608 6592 AIFB • Representation Language: Predicate Logic (F-Logic) • Standards: RDF(S); OWL Steffen Staab (13) ISWeb – Informationssysteme & Semantic Web Ontologies - Some Examples • General purpose ontologies: – DOLCE, http://www.loa-cnr.it/DOLCE.html – The Upper Cyc Ontology, http://www.cyc.com/cyc-2-1/index.html – IEEE Standard Upper Ontology, http://suo.ieee.org/ • Domain and application-specific ontologies: – GALEN, http://www.openclinical.org/prj_galen.html – Foundational Model of Anatomy, http://sig.biostr.washington.edu/projects/fm/AboutFM.html – RETSINA Calendering Agent, http://ilrt.org/discovery/2001/06/schemas/ical-full/hybrid.rdf – Dublin Core, http://dublincore.org/ • Semantic Desktop Ontologies – Semantics-Aware instant Messaging: SAM Ontology, http://www.uni-koblenz.de/FB4/Institutes/IFI/AGStaab/Research/sam – Haystack, http://haystack.lcs.mit.edu/ – Gnowsis, http://www.gnowsis.org/ – Piggybank, http://simile.mit.edu/piggy-bank/ • Web Services Ontologies – Core ontology of services http://cos.ontoware.org – Web Service Modeling ontology http://www.wsmo.org –OWL-S, http://www.daml.org/services/owl-s/1.0/ • Ontologies in a wider sense – GO - Gene Ontology, http://www.geneontology.org/ –UMLS, http://www.nlm.nih.gov/research/umls/ – Agrovoc, http://www.fao.org/agrovoc/ – Art and Architecture, http://www.getty.edu/research/tools/vocabulary/aat/ – DTD standardizations, e.g. HR-XML, http://www.hr-xml.org/ – WordNet / EuroWordNet, http://www.cogsci.princeton.edu/~wn Steffen Staab (14) ISWeb – Informationssysteme & Semantic Web Ontologies and Their Relatives General Formal logical Is-a constraints Catalog / ID Thesauri Frames Informal Terms/ Formal Value Is-a Axioms Glossary Instance Restric- Disjoint tions Inverse Relations, ... Steffen Staab (15) ISWeb – Informationssysteme & Semantic Web Ontologies and Their Relatives (cont´d) Topic Maps Front-End Thesauri Navigation Taxonomies Information Retrieval Query Expansion Sharing of Knowledge Queries Ontologies Semantic Networks Consistency Checking EAI Mediation Reasoning Extended ER-Models Predicate Logic Back-End Steffen Staab (16) ISWeb – Informationssysteme & Semantic Web Applications of Ontologies • Natural Language Processing and Machine Translation, e.g. Nirenburg et al. 2004, Maedche et al. 2001, Agirre et al. 1996, Beale et al. 1995 • Semantic Web, see http://www.w3.org/2001/sw/ and http://www.w3.org/2001/sw/WebOnt/ • Knowledge Engineering & Management, e.g. Fensel 2001, Mullholland et al. 2000; Staab & Schnurr, 2000; Sure et al., 2000, Abecker et al. 1997 • Electronic Commerce, e.g. RosettaNet3 and Ontology.org4 • Information Retrieval and Information Integration, e.g. Kashyap, 1999; Mena et al., 1998; Wiederhold, 1992 • Intelligent Search Engines, e.g. WebKB (Martin et al. 2000), SHOE (Heflin & Hendler, 2000), OntoSeek (Guarino et al., 1999), Ontobroker (Decker et al., 1999) • Digital Libraries, e.g. Amann & Fundulaki, 1999 • Enhanced User Interfaces, e.g. (Kesseler, 1996), Inxight5 • Software Agents, e.g. OnTo-agents, FIPA, (Gluschko et al., 1999; Smith & Poulter, 1999) • Business Process Modeling, e.g. Decker et al., 1997; TOVE, 1995; Uschold et al., 1998 Steffen Staab (17) ISWeb – Informationssysteme & Semantic Web Overview Literature S. Staab, R. Studer. Handbook on Ontologies. Springer, 2004. Steffen Staab (18) ISWeb – Informationssysteme & Semantic Web Part II Introduction to Semantic Web Steffen Staab (1) ISWeb – Informationssysteme & Semantic Web Syntax is not sufficient Andreas • Tel • E-Mail Steffen Staab (2) ISWeb – Informationssysteme & Semantic Web Information Convergence • Convergence not just in devices, also in “information” – Your personal information (phone, PDA,…) Calendar, photo, home page, files… – Your “professional” life (laptop, desktop, … Grid) Web site, publications, files, databases, … – Your “community” contexts (Web) Hobbies, blogs, fanfic, social networks… • The Web teaches us that people will work to share – How do we CREATE, SEARCH, and BROWSE in the non-text based parts of our lives? Steffen Staab (3) ISWeb – Informationssysteme & Semantic Web WWW vs. Semantic Web WWW := Semantic Web := Hypertext & Semantic Web Language/Data & Internet & Ontologies & Social Phenomenon Internet & Social Phenomenon Steffen Staab (4) ISWeb – Informationssysteme & Semantic Web Let’s try XML XML is unspecific: n No predetermined vocabulary o No semantics for relationships Ön& o must be specified upfront Only possible in close cooperations – Small, reasonably stable group – Common interests or authorities Not possible in the Web or on a broad scale in general ! Steffen Staab (5) ISWeb – Informationssysteme & Semantic Web Meaning of Informationen: (or: what it means to be a computer) name education CV work private Steffen Staab (6) ISWeb – Informationssysteme & Semantic Web XML ≠ Meaning, XML = Structure < name ναµε > <<εδυχατιον education > < CVΧς >> <<ωορκ work >> <<πριϖατε private >> Steffen Staab (7) ISWeb – Informationssysteme & Semantic Web Some Principal Ideas • URI – uniform resource identifiers • XML – common syntax • Interlinked Tim Berners- Lee, Weaving • Layers of semantics – the Web from database to knowledge base to proofs Design principles of WWW applied to Semantics!! Steffen Staab (8) ISWeb – Informationssysteme & Semantic Web TheSemanticWeb on oneSlide cooperatesWithcooperatesWith Ontology rdfs:Domain rdfs:Range PersonPerson rdfs:subClass EmployeeEmployee rdfs:subClass rdfs:subClass PostDocPostDoc ProfessorProfessor rdf:type rdf:type <swrc:PostDoc rdf:ID="person_sha"> <swrc:Professor <swrc:name>Siegfried Handschuh</swrc:name> rdf:ID="person_sst"> <swrc:name>Steffen Staab Meta- <swrc:cooperatesWith rdf:resource = </swrc:name> "http://www.uni-koblenz.de/~staab/ data #person_sst"/> ... </swrc:Professor> ... </swrc:PostDoc> swrc:cooperatesWith Web page Steffen Staab (9) URL http://www.deri.ie/~shaISWeb – Informationssysteme & Semantic Webhttp://www.uni-koblenz.de/~staab The Semantic