Introducing the Semantic Web

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Oct 20, 2013 (3 years and 1 month ago)

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Introducing the Semantic Web

Professor James Hendler

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

Co
-
Director, Maryland Information and Network Dynamics
Laboratory

Semantic Web Agents Project

http://www.mindswap.org


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

1990

2000

2010

Berners
-
Lee, Hendler;
Nature
, 2001

DOCUMENTS

DATA/PROGRAMS

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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

< >

< >

< >

< >

< >

<
CV

>

<

name

>

<
education
>

<
work
>

<
private
>

䉵琠瑯ty潵爠浡捨楮攬m

the tags look like this….

Schemas take a step in the right direction

Schemas help….

<
CV

>

…by relating

common terms

between documents

private

But other people use other schemas

CV

name

education

work

private

< >

< >

< >

< >

< >

<
CV

>

name
>

<
educ
>

<>

<

>

Someone else has one like this….

The “semantics” isn’t there

<
CV

>

…which don’t fit in

private

KR provides “external” referents to merge on

SW languages add mappings

And structure.

nme

work

vate

educ

CV

CV


CV

ed
uc

CV

name

education

work

private

< >

< >

< >

< >

< >

<

CV


>

<

name

>

<

educ

>

<>

<



>

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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

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J. Hendler, 2002

Putting semantics on the web

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J. Hendler, 2002

(and making it machine
-
readable)

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J. Hendler, 2002

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J. Hendler, 2002

Event:title

Event:WebPage

< > rdf:type photo:Photograph,


Photo:File http://…/images#image1,


Photo:topic :event1#event:speaker.


Event1 a Event:event;


date “May 7
-
11”,


speaker http://…#timbl.html


Title “WWW 2002…”

TimBL rdf:type w3c
-
ont:person;


name “Tim Berners
-
Lee”





<daml:ObjectProperty rdf:ID="photograph">

<rdfs:domain rdf:resource="#Picture"/>

<rdfs:range rdf:resource= …#person"/>

</daml:ObjectProperty>




<rdf:Description rdf:about="http://www.w3.org/2001/03/earl/0.95#Person">

<rdf:type rdf:resource="http://www.w3.org/2000/01/rdf
-
schema#Class"/>

<rdfs:subClassOf rdf:resource="http://www.w3.org/2001/03/earl/0.95#Assertor"/>

</rdf:Description>

<s:Class
rdf:about="http://www.semanticweb.org/o
ntologies/swrc
-
onto
-
2000
-
09
-
10.daml#Conference">

<s:comment>

describes a generic conceptabout events


</s:comment>

<s:subClassOf
rdf:resource="http://www.semanticweb.or
g/ontologies/swrc
-
onto
-
2000
-
09
-
10.daml#Event"/>

<a:disjointFrom
rdf:resource="http://www.semanticweb.or
g/ontologies/swrc
-
onto
-
2000
-
09
-
10.daml#Workshop"/>

<a:restrictedBy
rdf:resource="http://www.semanticweb.or
g/ontologies/swrc
-
onto
-
2000
-
09
-
10.daml#genid18"/>

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J. Hendler, 2002

On the Web
--

links are critical!

<a href=

URI>

HTML

Web page

Any Web Resource

<a href=“http://…”>

RDF

URI

URI

URI

RDF is like the web! And…

On the Semantic WEB
--

links are critical!

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J. Hendler, 2002

<mind:Person rdf:id=“Hendler”>


<mind:title jobs:Professor>


<jobs:placeOfWork
http://www.cs.umd.edu>

</mind:Person>

DOC1

Hendler

DOC1

Mind:title

Jobs:placeOfWork

Web Page

http://www…

Professor

Jobs:

Mind:

Jobs:

RDF graphs resemble semantic nets

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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

http://www…

Professor

Jobs:

Mind:

Jobs:

Other

Professors

Other

Pages

Other

title
s

Other

description
s

Other

URI
s

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J. Hendler, 2002

Radically new view of Semantics

Distributed,partially mapped, inconsistent
--

but SCALEABLE!

uses

uses

uses

uses

uses

uses

uses

uses



uses

uses

uses

uses

uses

uses

uses

uses



uses

uses

uses

uses

uses

uses

uses

uses



uses

uses

uses

uses

uses

uses

uses

uses



uses

uses

uses

uses

uses

uses

uses

uses



uses

uses

uses

uses

uses

uses

uses

uses



= some partial mapping

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J. Hendler, 2002

Real examples


Examples from
http://dormouse.cs.umd.edu:8080/wiki/cmsc498wiki.wiki


Students violated every rule in the KR book


Extended existing ontologies


Linked instances directly to terms from multiple ontologies


Mixed “real KR” and NL


We can learn from their lessons


http://dormouse.cs.umd.edu:8080/wiki/assignment1_collected_les.wiki

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J. Hendler, 2002

Current Activities

Semantic Web LayerCake
(Berners
-
Lee, 99;Swartz
-
Hendler, 2001)

You

are

here

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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. “


History


DAML+OIL is submitted as a
joint committee
effort published as a
W3C note

.


W3C WG Announcement in November 2001
-

http://lists.w3.org/Archives/Public/www
-
rdf
-
logic/2001Nov/0000.html



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.


Four Working Drafts to date


Requirements/Use cases
-

March 2002


3 Technical Documents
-

July 2002
(Language renamed
OWL
)

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J. Hendler, 2002

Membership


Current
Working

Group includes over 50 members from over 30 organizations.


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)

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J. Hendler, 2002

But will it fly?


DAML+OIL is already the most used ontology language ever!!


http://www.daml.org

(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


Much New Startup activity (even in this economic climate)


Many tools being developed


Many of them aimed at developers, not just AI literate types

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J. Hendler, 2002

Making Markup Easier

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Machine worries about the syntax

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Use that markup in query/portal interfaces

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Extending ontologies on the fly

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J. Hendler, 2002

Semantic Web Portals:


The
Mosaic

of the semantic web?

<Oncogene rdf:ID="Oncogene,
MYB"><code>C3682</code><id>3683</id>

<Found_In_Organism
rdf:ID="Human"></Found_In_Organism>

<Gene_Has_Function rdf:ID="Gene
Transcription"></Gene_Has_Function>

<Gene_Has_Function
rdf:ID="Transcriptional
Regulation"></Gene_Has_Function>

<In_Chromosomal_Location rdf:ID="6q22
-
q23"/>

</Oncogene>

<
Oncogene rdf:ID="Oncogene NMYC">

<code>C17656</code><id>17657</id><Found_In_Organism
rdf:ID="Human"></Found_In_Organism>

<In_Chromosomal_Location rdf:ID="2p24.1"/>

<Gene_Has_Function rdf:ID="Transcriptional Regulation">

</Gene_Has_Function><Gene_Associated_With_Disease
rdf:ID="Neuroblastoma">

</Gene_Associated_With_Disease></Oncogene>

<XSLT/>

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J. Hendler, 2002

Moving to the futureof the web

Semantic Web LayerCake
(Berners
-
Lee, 99;Swartz
-
Hendler, 2001)

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J. Hendler, 2002

Web “travel agents”

Query processed:
73 answers found


Google
document search finds 235,312 possible page hits.


Http://www…/CowTexas.html

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?

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Allows new capabilities

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Services off the desktop

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Or perhaps on different desktops…

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Web Agents need Service
Descriptions

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J. Hendler, 2002

Semantic Web Service Description

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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)


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J. Hendler, 2002

Or, translate to Planning Operators

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For goal
-
based service composition

Buy the French version of a book from amazon.fr and

have it sent to Mom’s address

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Services need Web Logics

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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(

http://www.cs.umd.edu/university
-
list”
,
u)

Notice this one

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J. Hendler, 2002

Distributed Trust

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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!