Introducing the Semantic Web Professor James Hendler Co-Director, Maryland Information and Network Dynamics Laboratory Semantic Web Agents Project

3 J. Hendler, 2002 The Evolving Web Web of Knowledge HyperText Markup Language HyperText Transfer Protocol Resource Description Framework eXtensible Markup Language Self-Describing Documents Foundation of the Current Web Proof, Logic and Ontology Languages Shared terms/terminology Machine-Machine communication Berners-Lee, Hendler; Nature, 2001 DOCUMENTS DATA/PROGRAMS

4 J. Hendler, 2002 Web Semantics Semantic Web LayerCake (Berners-Lee, 99;Swartz-Hendler, 2001)

Can’t we just use XML? This is what a web-page in natural language looks like for a machine

XML helps CV name education work private XML allows “meaningful tags” to be added to parts of the text

XML  machine accessible meaning CV name education work private But to your machine, the tags look like this….

Schemas take a step in the right direction Schemas help…. …by relating common terms between documents 

But other people use other schemas CV name education work private   >  Someone else has one like this….

The “semantics” isn’t there …which don’t fit in 

KR provides “external” referents to merge on SW languages add mappings And structure.        CV name education work private <  > <  > <  >  <  „  >

12 J. Hendler, 2002 Which is what the web was meant to be!! "This is a pity, as in fact documents on the web describe real objects and imaginary concepts, and give particular relationships between them... For example, a document might describe a person. The title document to a house describes a house and also the ownership relation with a person.... This means that machines, as well as people operating on the web of information, can do real things. For example, a program could search for a house and negotiate transfer of ownership of the house to a new owner. The land registry guarantees that the title actually represents reality.”  Tim Berners-Lee plenary presentation at WWW Geneva, 1994

13 J. Hendler, 2002 Putting semantics on the web

14 J. Hendler, 2002 (and making it machine-readable)

15 J. Hendler, 2002

16 J. Hendler, 2002 Event:title Event:WebPage rdf:type photo:Photograph, Photo:File Photo:topic :event1#event:speaker. Event1 a Event:event; date “May 7-11”, speaker Title “WWW 2002…” TimBL rdf:type w3c-ont:person; name “Tim Berners-Lee” … describes a generic conceptabout events

17 J. Hendler, 2002 On the Web -- links are critical! <a href=URI> HTML Web page Any Web Resource RDF URI RDF is like the web! And… On the Semantic WEB -- links are critical!

18 J. Hendler, DOC1 Hendler DOC1 Mind:title Jobs:placeOfWork Web Page Professor Jobs: Mind: Jobs: RDF graphs resemble semantic nets

19 J. Hendler, 2002 Semantics on the WEB RDF, like the WWW itself, is not “separable”  Thinking about the ontologies, without considering The links to other terms The instances that link to them The crawling and collecting of ontological terminologues Is like thinking about the Web without the links!! Hendler DOC1 Mind:title Jobs:placeOfWork Web Page Professor Jobs: Mind: Jobs: Other Professors Other Pages Other titles Other descriptions Other URIs

20 J. Hendler, 2002 Radically new view of Semantics Distributed,partially mapped, inconsistent -- but SCALEABLE! uses = some partial mapping

21 J. Hendler, 2002 Real examples Examples from Students violated every rule in the KR book  Extended existing ontologies Extended existing ontologies  Linked instances directly to terms from multiple ontologies Linked instances directly to terms from multiple ontologies  Mixed “real KR” and NL Mixed “real KR” and NL We can learn from their lessons 

22 J. Hendler, 2002 Current Activities Semantic Web LayerCake (Berners-Lee, 99;Swartz-Hendler, 2001) You are here

23 J. Hendler, 2002 W3C Web Ontology Working Group Web Ontology Working Group in the W3C Semantic Web Activity aimed at “extending the semantic reach of current XML and RDF meta-data efforts. “W3C Semantic Web Activity History  DAML+OIL is submitted as a joint committee effort published as a W3C note.joint committee W3C note  W3C WG Announcement in November  Weekly teleconferences started in November 2001  First Face to Face Meeting - New Jersey (Lucent), Jan ‘02; 2nd - Amsterdam April (W3C); 3rd - CA (Fujitsu/Stanford host) July; 4th in Bristol UK (HP Host) Oct.Face to Face Meeting  Four Working Drafts to date Requirements/Use cases - March Technical Documents - July 2002 (Language renamed OWL )

24 J. Hendler, 2002 Membership Current Working Group includes over 50 members from over 30 organizations.Working  Chairs J. Hendler, MIND Lab UMCP G. Schreiber, Univ. of Amsterdam  Industry including: Large companies - Daimler Chrysler, IBM, HP, Intel, EDS, Fujitsu, Lucent, Motorola, Nokia, Philips Electronics, Sun, Unisys Newer/smaller companies - IVIS Group, Network Inference, Stilo Technology, Unicorn Solutions  Government and Not-For-Profits: US Defense Information Systems Agency, Interoperability Technology Association for Information Processing, Japan (INTAP), Electricite De France, Mitre, NIST  Universities and Research Centers: University of Bristol, University of Maryland, University of Southamptom, Stanford University DFKI (German Research Center for Artificial Intelligence), Forschungszentrum Informatik, Ontoweb  Invited Experts Well-known academics from non-W3C members (Hayes, Heflin, Stein, Borden)

25 J. Hendler, 2002 But will it fly? DAML+OIL is already the most used ontology language ever!!  (3.5M statements on 25,000 web pages) Gaining acceptance by web players  Semantic Web Track being offered at WWW 2002  3x more people attended WWW2002 Developer Day on SW than attended KR Significant (international) Govt Support  US DARPA/NSF; EU IST Framework 5,6  Japan, Germany, Australia considering significant investments  US National Cancer Institute to publish cancer vocabulary in DAML+OIL US National Cancer Institute to publish cancer vocabulary in DAML+OIL Much New Startup activity (even in this economic climate) Many tools being developed  Many of them aimed at developers, not just AI literate types

26 J. Hendler, 2002 Making Markup Easier

27 J. Hendler, 2002 Machine worries about the syntax

28 J. Hendler, 2002 Use that markup in query/portal interfaces

29 J. Hendler, 2002 Extending ontologies on the fly

30 J. Hendler, 2002 Semantic Web Portals: The Mosaic of the semantic web? C C

31 J. Hendler, 2002 Moving to the futureof the web Semantic Web LayerCake (Berners-Lee, 99;Swartz-Hendler, 2001)

32 J. Hendler, 2002 Web “travel agents” Query processed: 73 answers found  Google document search finds 235,312 possible page hits.  claims the answer is 289,921,836  A database entitled “Texas Cattle Association” can be queried for the answer, but you will need “authorization as a state employee.”  A computer program that can compute that number is offered by the State of Texas Cattleman’s Cooperative, click here to run program. ...  The “sex network” can answer anything that troubles you, click here for relief...  The “UFO network” claims the “all cows in Texas have been replaced by aliens How many cows are there in Texas?

33 J. Hendler, 2002 Allows new capabilities

34 J. Hendler, 2002 Services off the desktop

35 J. Hendler, 2002 Or perhaps on different desktops…

36 J. Hendler, 2002 Web Agents need Service Descriptions

37 J. Hendler, 2002 Semantic Web Service Description

38 J. Hendler, 2002 Use Semantics for Composition Translate my symptoms from French and find me a pharmacy that has the necessary medicine (then compute how to get there and print the directions) Print the directions to a pharmacy which has a medicine that cures the symptoms that I will tell you (in French)

39 J. Hendler, 2002 Or, translate to Planning Operators

40 J. Hendler, 2002 For goal-based service composition Buy the French version of a book from amazon.fr and have it sent to Mom’s address

41 J. Hendler, 2002 Services need Web Logics

42 J. Hendler, 2002 Web of Trust Claims can be verified if there is supporting evidence from another (trusted) source  We only believe that someone is a professor at a university if the university also claims that person is a professor, and the university is on a list I trust. believe(c1) :- claims(x, c1) ^ predicate(c1, professorAt) ^ arg1(c1, x) ^ arg2(c1, y) ^ claims(c2, y) ^ predicate(c2, professorAt) ^ arg1(c2, x) ^ arg2(c2, y) ^ AccreditedUniversity(y) AcknowledgedUniversity(u) :- link-from( “ u) Notice this one

43 J. Hendler, 2002 Distributed Trust

44 J. Hendler, 2002 Conclusion It is no longer a question of whether the semantic web will come into being, it is already here! We’re already well past the starting gate  Web ontologies, term languages, “shims” to DB and services, research in proofs/rules/trust  Standardization providing a common denominator for KR researchers as well as web developers  Small companies starting to form, Big companies starting to move The current environment is open, encouraging, moving fast, and exciting as heck  Come play!