The Semantic Web: A network of understanding Jim Hendler Univ of MD/RPI hendler.

The Semantic Web:A network of understanding

Jim Hendler

Univ of MD/RPI

http://www.cs.umd.edu/~hendler

ASWC 2006

Outline

• The Semantic Web• Past

• Present

• Future

May, 2001

March, 2000

May, 1994

ASWC 2006

Burkitt’s Lymphoma Rearrangement of a DNA sequence homologous to a <cell-type>cell-virus junction fragment </cell-type>in several<disease>Moloney murine leukemia</disease> virus-induced <organism>rat</organism> thymomas

Burkitt’s Lymphoma Rearrangement of a DNA sequence homologous to a cell-virus junction fragment in several Moloney murine leukemia virus-induced rat thymomas

8q24PVT1

Oncogene(MYC): Found_In_Organism(Human). Gene_Has_Function(Transcriptional_Regulation). Gene_Has_Function(Gene_Transcription). In_Chromosomal_Location(8q24). Gene_Associated_With_Disease(Burkitts_Lymphoma).

PubMed

PubMed

Semantic Web

PVT

PVT

Semantic Web hypothesis: Heterogeneous Web-based Information Resources can be connected by Web-based knowledge models

ASWC 2006

• Web Ontologies are models allowing the linking of • multimedia

• databases

• services• Web services

• Grid computing

• meta-data repos

• Or any other Web resource!

• Other ontologies

• Anything with a URI

Web ontologies

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The "layercake"

T. Berners-Lee, 2001

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2001

Recommendation

WG activity

Funded Research

1010

Semantic Web Today

l The Semantic Web of 2002 resembles the early days of theWorld Wide Web

u Development funded primarily by Govt, but emerging corporate interest

u A lot of excitement, but confusion as to business case

u Open source tools and “geeks in control”

u Standards starting to stabilize to point where they permit deployment

u Developer tools, libraries, languages

1010

Semantic Web Today







• Research, experimentation, early demonstrations

• Reminiscent of the early days of the Web

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2003

Recommendation

WG activity

Funded Research

1010

Semantic Web Today







1010

Semantic Web Today







23Sanken, 03 23 www.mindswap.org

“Our” Semantic Web

l Jan 1, 03: Crawler finds 5.8M+ DAML statements on 20,000+ web pagesu Doesn’t include many instance KBs tied to ontologiesu Doesn’t include many very large RDFS-based KBs that include some OWL

l Ontology library at http://www.daml.org has 195 ontologies (March 2003)u Open for anyone to createu Open for anyone to use

l OWL is being supported by large corporation labsu Web tool developers: IBM, HP, Sun, Intel, Fujitsuu Content providers: Daimler-Chrysler, Nokia, Motorola, EDS, Agfa

l OWL is starting to be used by thesaurus developersu C.f. National Cancer Institute metathesaurus released in OWL Liteu United Nations Standard Product Codes available in DAMLu NASA thesaurus available in DAML

l Use of semantic markup for Web Services beginning to move beyond basicresearch

u DAML-S cited as required reading for Web Services Composition WG









• Early government adoption

• Emerging corporate interest

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2005

Recommendation

WG activity

Funded Research

1010

Semantic Web Today







1010

Semantic Web Today























• Commercial tools

• Lots of open source software

• ScalabilitySemTechConf , 3/05

QuickTime™ and aTIFF (LZW) decompressorare needed to see this picture.

Now• Companies getting into the act

• IBM SNObase ontology management system• Oracle to support RDF in Oracle 10.2• Open source (Kowari) scalable triple store

• Supports RDFS• OWL support coming

• HP Labs open-source Jena API

• Many open source tools becoming available forexperimentation/academic use• Kowari, RDFLib, 3Store…• Jena, Sesame …• Protégé, SWOOP, Onto(xxx)…

• Building corporate demonstrators becoming cheap andeasy

SemTechConf , 3/05

QuickTime™ and aTIFF (LZW) decompressorare needed to see this picture.

Now• Companies getting into the act

• IBM SNObase ontology management system• Oracle to support RDF in Oracle 10.2• Open source (Kowari) scalable triple store

• Supports RDFS• OWL support coming

• HP Labs open-source Jena API

• Many open source tools becoming available forexperimentation/academic use• Kowari, RDFLib, 3Store…• Jena, Sesame …• Protégé, SWOOP, Onto(xxx)…

• Building corporate demonstrators becoming cheap andeasy

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

ASWC 2006

l Resource Description Framework (RDF)u Few, but important, constraintu A basic, extensible assertional language

l RDF Schema (RDFS)u Weak structuring of sets of terms (taxonomy-esque)u Class and property hierarchiesu Domain and Range constraints

l The Web Ontology Language, OWLu Stronger structuring of sets of terms (ontologies)u Everything in RDFS plus

l Complex Class constructors (unionOf, intersectionOf)l Additional property features (inverse, transitive)l Class local property type and cardinality constraintsl And more

Web Modeling Languages - 2005

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2006: You Are Here!

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Significant Corporate Activity

• Semantic (Web) technology companies starting & growing • Siderean, SandPiper, SiberLogic, Ontology Works, Intellidimension,

Intellisophic, TopQuadrant, Data Grid, …

• Bigger players buying in• Adobe, Cisco, HP, IBM, Nokia, Oracle, Sun, Vodaphone…

announcements/use in 2005-2006• Gartner identifies Corporate Semantic Web as one of three "High impact"

Web technologies• tools being announced: AllegroGraph, Altova, TopBraid, …

• Government projects in and across agencies• US, UK, EU, Japan, Korea, …

• Life sciences/pharma an increasingly important market• Health Care and Life Sciences Interest Group at W3C

• Many open source tools available • Kowari, RDFLib, Jena, Sesame, Protégé, SWOOP, Onto(xxx), Wilbur, …

ASWC 2006

Data harvesting & visualization

Richer metadata

<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"> <rdf:Description rdf:about="" xmlns:pdf="http://ns.adobe.com/pdf/1.3/"> <pdf:Producer>Acrobat Distiller 7.0.5 for Macintosh< /pdf:Producer> </rdf:Description> <rdf:Description rdf:about="" xmlns:dc="http://purl.org/dc/elements/1.1/"> <dc:format> application/pdf </dc:format> <dc:creator> < rdf:Seq> < rdf:li>James Hendler< /rdf:li> < /rdf:Seq> </dc:creator> <dc:title> < rdf:Alt> < rdf:li xml:lang="x-default" >XMLideas.ppt</rdf:li> < /rdf:Alt> </dc:title> </rdf:Description> <rdf:Description rdf:about="" xmlns:xapMM="http://ns.adobe.com/xap/1.0/mm/"> <xapMM:DocumentID>uuid:93277c40-5534-11da-a3f2-000a95d6b344< /xapMM:DocumentID> <xapMM:InstanceID>uuid:9327882b-5534-11da-a3f2-000a95d6b344< /xapMM:InstanceID> </rdf:Description> </rdf:RDF>

Embedded meta-data

Enterprise data integration

"Corporate Semantic Web", Gartner "hot pick" for 2006

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Digital asset management Semantic Web portals

Ontology editors (and other tools) Semantic Web and social networking

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Significant Corporate Activity

50+ Semantic Web press releases each month

50+ Semantic Web press releases each month

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Significant Government Activity

Lots of activities across NASA• Science, Engineering, and Mission all have SWT

production or development efforts in place• Now focus in on re-using the data systems we already

have in place• Agency wide

integration planningis underway forbuilding a federationof models into anintegrated informationservice across alldisciplines

Lots of activities across NASA• Science, Engineering, and Mission all have SWT

production or development efforts in place• Now focus in on re-using the data systems we already

have in place• Agency wide

integration planningis underway forbuilding a federationof models into anintegrated informationservice across alldisciplines

• Agencies moving beyond the "talk" phase

• primarily prototyping, but first acquisitions starting

• Example:• NASA is developing

an enterprise data strategy around using existing data via Semantic Web integration (A. Schain, 3/06)

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There's a Lot Out There!

2,120,000 hits on"RDF filetype:rdf"2,120,000 hits on"RDF filetype:rdf"

13,600 hits on"ontology filetype:owl"13,600 hits on"ontology filetype:owl"

Paid ads

(March, 2006)

ASWC 2006

Where we are today

• Survey of 1300 OWL ontologies found by crawl

• Wang 06

• 19 ontologies with 2000+ classes

• 6 ontologies with 10000+ classes

• 2 ontologies with50000+ classes

• CYC, NCI

Species RDFS OWL Lite OWL DL OWL Full Error

Count 587 199 149 337 3

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Swoogle

http://swoogle.umbc.edu

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Some "Swoogle" observations

Owl:Class is the most used term from the OWL namespace with ~ 1,800.000 instantiations in 68,000 SWDs

The OWL namespace has been declared by 113,000 SWDs (8%) and actually used by 108,000 (7%). The RDFS namespace enjoys more use, being declared by 677,000 (47%) and used by 538,000 (37%) SWDs.

We also noticed significant use of two OWL equality assertions: owl:sameAs (280,000 assertions in 17,00 SWDs) and owl:equivalentClass (70,000 assertions in 4,300 SWDs). Their common use may be an indication of increased ontology alignment.

(Ebiquity blog, Sept 1, 2006)

ASWC 2006

The cake is evolving as well..

2001 2006(Tim Berners-Lee) (Tim Berners-Lee)

ASWC 2006

New languages underway

• SPARQL• Query language for (distributed) RDF triple stores

• The SQL of the Semantic Web

• GRDDL/RDFa• Integration of HTML world and Semantic Web

• Means for "embedding" RDF-based annotation on traditional Web pages• Means for generating RDF triple stores from (annotated) Web pages

• RIF• Rules interchange format

• Representing rules on the Web• Linking rule-based systems together

• And more• Multimedia annotation, Web-page Metadata annotation, Health Care and

Life Science (LSID), Privacy

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Next Steps

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The Great Wall

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Built in pieces at different times

Linked together for greater effect

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Linking of"Web Islands"

The World Wide Web

Linked together for greater effect

Built in pieces at different times

ASWC 2006

Linking is power!

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE rdf:RDF [ <!ENTITY feleuk.owl "http://www.mindswap.org/ontologies/feleuk.owl"> <!ENTITY owl "http://www.w3.org/2002/07/owl#"> <!ENTITY rdf "http://www.w3.org/1999/02/22-rdf-syntax-ns#"> <!ENTITY rdfs "http://www.w3.org/2000/01/rdf-schema#"> <!ENTITY NCI "http://www.ncibi.nih.gov/NCIT/NCIT.owl#"> <!ENTITY CYC="http://www.cyc.com/2004/06/04/cyc#"> ]><rdf:RDF xml:base="&feleuk.owl;" xmlns:owl="&owl;" xmlns:rdf="&rdf;" xmlns:rdfs="&rdfs;" xmlns:NCI="&NCI;" xmlns:CYC="&CYC;">

<owl:Ontology rdf:about="" rdfs:label="Feline Leukemia" owl:versionInfo="Feline Leuk 1.0"/>

<owl:Class rdf:about="#Feline-Leukemia"> <rdfs:subClassOf rdf:resource="NCI:Leukemia"/> <rdfs:subClassOf> <owl:Restriction> <owl:allValuesFrom rdf:resource="CYC:cat"/> <owl:onProperty rdf:resource="#NCI:diseased-organism"/> </owl:Restriction> </rdfs:subClassOf> </owl:Class>

</rdf:RDF>

Link to 45000 terms at NCI

Link to 47000 (Open)CYC terms

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Linking is power

• Today we can find thousands of ontologies• Available on the Web

• Linked to Web resources• Linked to data resources• Linked to each other• Linked to Web 2.0-like annotations

• And billions of annotated (semi-Knowledge engineered) objects • Available on the Web

• Linked to Web resources• Linked to data resources• Linked to each other• Linked to the ontologies

We must link these together for great effect!!

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A key opportunity

• Vast amounts of "semi-engineered" knowledge• Flickr: tens of millions of keyword tagged photos• Wikipedia: thousands of carefully documented subjects

(in a hierarchy, with disambiguation, …)• Etc. etc. etc.

• With "persistent" URIs• "tank" http://en.wikipedia.org/wiki/Tank (armament)• "tank" http://en.wikipedia.org/wiki/Tank%2C_Pakistan

(small town in Pakistan)

• And anything with a URI can be linked to the Semantic Web!!!!!

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For exciting linking possibilities

• Linking of Web 2.0 and Semantic Web• Using

informal KE to bootstrap "formal" KE

• Extending formal KE from Web 2.0

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Documents, linked to

Images, annotated with

Ontologies, linked to

Other ontologies, describing

Databases, exported as

RDF graphs, as input to

Services, which designate

Documents, linked to …

(ad infinitum)

Evolving vision

1994

2000

2001

Stay tuned…

ASWC 2006

Semantic Web Challenges

• Today's Semantic Web Languages • Are not-very-expressive-KR-language standards

• Not KIF, or even KL-ONE

• Create non-persistent knowledge bases• Servers come and go• Ontologies change over time

• And can't be kept consistent• Disagreement, error, dishonesty…

ASWC 2006

Semantic Web opportunities

• Today's Semantic Web Languages • Are not-very-expressive-KR-language standards

• Like HTML is to SGML

• Create non-persistent KBs• Like the 404 error (w/o which there is no Web)

• And can't be kept consistent• Like blog-space and Web 2.0

• We need to accept, and more importantly exploit, these features

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Note to Grad students (and their advisors)

• The Semantic Web today, esp at the ontology layer, is like the Web with no one using <a href=…> • What makes the Web, the Web

• Please, No more one ontology, one domain, one set of services, one … Theses• There's a reason we built this stuff on top of RDF and URIs

The network effect is where the power is!

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A few of the many things I've left out

• Semantic Web Services• Crucial for linking "programs" into the mix

• Semantic Web tools and scaling issues• Engineering approaches being used to scale Semantic Web stores to

database sizes

• Information extraction and Semantics• Can we "retrofit" semantics on the existing Web

• Semantic Web Information Creations• Can we make it so we don't have to retrofit future Web?

• Other information resources• Personal data, unstructured resources, off-line collection information, digital

libraries, …• There's more that isn't on the Web than is on it!

• New Web use patterns• Social networks, blogs, wikis, …• … are all fertile areas for Semantic Web exploration

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Conclusion

• The Semantic Web is real• Tremendous progress in the past five years• Lots of it is out there• Growing support in industry and govt use

• Development continues• Easy to get involved

• Many open source tools

• New languages and techniques reaching critical mass

• The next steps are exciting• The "network effect" of linking to other Semantic Web resources• … and to non-Semantic Web resources

• And research opportunities still abound• Scaling• Inconsistency• Access and acquisition

ASWC 2006

The SEMANTIC WEB

The Semantic Web: A network of understanding Jim Hendler Univ of MD/RPI hendler.

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Transcript of The Semantic Web: A network of understanding Jim Hendler Univ of MD/RPI hendler.