1KR2002, Apr 2002
KR: Reinjecting Reality
Mathematical ideas originate in empirics .. But, once they are so conceived, the subject begins to live a peculiar life of its own and is better compared to a creative one, governed almost entirely by aesthetical motivations …As a mathematical discipline travels, or after much abstract inbreeding, [it] is in danger of degeneration…whenever this stage is reached, the only remedy seems to me to be the rejuvenating return to the source; the reinjection of more or less directly empirical ideas
--- John Von Neumann, 1953
The Semantic Web: KR’s Worst Nightmare?
Professor James Hendlerhttp://www.cs.umd.edu/~hendler
Co-Director, Maryland Information and Network Dynamics Laboratory
3KR2002, Apr 2002
The nightmare: KR becomes relevant
Artificial Intelligence researchers have studied such systems since long before the web was developed. Knowledge representation, as this technology is often called, is currently in a state comparable to that of hypertext before the advent of the web: it is clearly a good idea, and some very nice demonstrations exist, but it has not yet changed the world. It contains the seeds of important applications, but to unleash its full power it must be linked into a single global system.
-- Tim Berners-Lee, inventor of the WWW, 2001.
4KR2002, Apr 2002
Outline
The SEMANTIC webThe semantic WEBWe’ve heard this kind of crap before, why
should we believe this one?Challenges aheadBut is it AI?
5KR2002, Apr 2002
The SEMANTIC Web
Event:title
Event:date
Event:Loc
< > a photo:Photograph, Photo:File http://…/images#image1, Photo:topic :event1#event:loc.
Event1 a Event:event; Event:date “April 22-25,2002”, Event:Loc http://…/Toulouse, Event:Title “Eighth…”.
6KR2002, Apr 2002
KR on the Web
Many characteristics of the Web violate traditional KR assumptions! It's Large and It Grows Fast High Variety in Quality of Knowledge Diversity of Content Unknown/unpredictable Use Scenarios for the Knowledge Problems of Trust, No Single Authority Lack of Referential Integrity Knowledge acquired, not engineered (Van Harmelen, 2000)
XML helps
CV
name
education
work
private
< >
< >
< >
< >
< >
XML allows “meaningful tags” to be added toparts 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….
CV
name
education
work
private
< >
< >
< >
< >
< >
< >
<>
<>
<>
<>
CV
name
education
work
private
< >
< >
< >
< >
< >
< >
<>
<>
<>
<>
< > …by relating common termsbetween documents
But other people use other schemas
CV
name
education
work
private
< >
< >
< >
< >
< >
< >
>
<>
<>
Someone else has one like this….
The “semantics” isn’t there
CV
name
education
work
private
< >
< >
< >
< >
< >
< >
<>
<>
<>
<>
CV
name
education
work
private
< >
< >
< >
< >
< >
< >
<>
<>
<>
<>
< >
…which don’t fit in
CV
name
education
work
private
< >
< >
< >
< >
< >
< CV >
<name >
<educ >
<>
<⇐∨ >
KR provides “external” referents to merge on
CV
name
education
work
private
< >
< >
< >
< >
< >
< >
<>
<>
<>
<>
CV
name
education
work
private
< >
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<>
<>
<>
<>
CV
name
education
work
private
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<>
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SW languages add mappingsAnd structure.
CV
name
education
work
private
< >
< >
< >
< >
< >
< CV >
<name >
<educ >
<>
<⇐∨ >
CV
name
education
work
private
< >
< >
< >
< >
< >
< CV >
<name >
<educ >
<>
<⇐∨ >
CV
name
education
work
private
< >
< >
< >
< >
< >
< CV >
<name >
<educ >
<>
<⇐∨ >
CV
name
education
work
private
< >
< >
< >
< >
< >
< CV >
<name >
<educ >
<>
<⇐∨ >
CV
name
education
work
private
< >
< >
< >
< >
< >
< CV >
<name >
<educ >
<>
<⇐∨ >
17KR2002, Apr 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
18KR2002, Apr 2002
The semantic WEB
StructuralGenomics
Population Genetics
Genome sequence
Functionalgenomics Tissue
Clinical trial
Disease
Clinical Data
(Genome World - from Goble, 01)
Goal: do to ontologies what the web does for documents
19KR2002, Apr 2002
This leads to a radically new view of interoperation
Distributed,partially mapped, inconsistent -- but very flexible!
uses
uses
uses
uses
usesuses
uses
uses
uses
uses
uses
uses
usesuses
uses
uses
uses
uses
uses
uses
usesuses
uses
uses
uses
uses
uses
uses
usesuses
uses
uses
uses
uses
uses
uses
usesuses
uses
uses
uses
uses
uses
uses
usesuses
uses
uses
= some partial mapping
21KR2002, Apr 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
22KR2002, Apr 2002
But will it fly
DAML+OIL is probably the most used AI language ever!! http://www.daml.org
Gaining acceptance by web players Semantic Web Track being offered at WWW 2002 More people will attend WWW2002 Developer Day on SW than attend 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
23KR2002, Apr 2002
W3C Web Ont WG
Current Working Group includes over 50 members from 30+ organizations. Industry including:
Large companies such as Sun, IBM, HP, Intel, EDS, Fujitsu, Lucent, Nokia, Philips Electronics, Unisys, Daimler0Chrysler
Newer/smaller companies such as 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 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 (From non-W3C members)
Well-known KR researchers (Hayes, Stein) Tool Developers (Dean, Heflin) Domain experts (Borden)
W3C Team Connolly (HTML, XML. XML-schema); Brickley (RDF, RDF Core)
24KR2002, Apr 2002
Moving to the futureof the web
Semantic Web LayerCake (Berners-Lee, 99;Swartz-Hendler, 2001)
25KR2002, Apr 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?
28KR2002, Apr 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(“http://www.cs.umd.edu/university-list”,u)
Notice this one
29KR2002, Apr 2002
Validation sites
Buy into your favorite rule set believable(x) :- claims(src,x) ^
accreditedbyChristianCoalition(src) believable(x) :- claims(src,x) ^
linkfromMomsPage(src) believable(x) :- claims(src,x) ^
accreditedby(“http://foo.com/Unabomber/Friends/rules”,src) ^ Not-accreditedbyChristianColation(x)
30KR2002, Apr 2002
But is it AI AI ?
What about human intelligence It's Large and It Grows Fast Lack of Referential Integrity High Variety in Quality of Knowledge Diversity of Content Unknown/unpredictable Use Scenarios for the Knowledge Problems of Trust, No Single Authority Knowledge acquired, not engineered
Many characteristics of human intelligence violate traditional KR assumptions It’s time for us to face up to the real challenge!!
31KR2002, Apr 2002
Conclusion
It is no longer a question of whether the semantic web could come into being, it can and will
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 KR community has lots to offer If, and maybe only if, it is willing to revisit some basic assumptions
The current environment is open, encouraging, moving fast, and exciting as heck Come play!