October 19, 2005 1
Semantic Web
October 19, 2005 2
Discipline
Standards
Tools
Content
Infrastructure
Semantic WebPart 3: Semantic
Web
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Should you care?
Did the World Wide Web affect you?Would you have wished you had more
advanced warning, earlier implication of the change?
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October 19, 2005 5
Look familiar?
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WWW growth
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The Semantic Web is Comparable
Not a different web, but an extension of the current one.
It is essentially the addition of “meaningful” tags to content on the web, such that software can help us find things.
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“I’ll Wait”
Lead timeSkills developmentLeadership
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Naysayers
Cory Doctorow: “Metacrap: Putting the torch to seven straw-men of the meta-utopia”
http://www.well.com/~doctorow/metacrap.htm
Russell Glass: “Is Anyone Going to Tag all this Stuff?”
http://zoominfo.blogs.com/soughtafter/2005/03/semantic_web_is.html
Clay Shirky: “The Semantic Web, Syllogism, and Worldview”
http://www.shirky.com/writings/semantic_syllogism.html
Peter Norvig, Google: “Semantic Web Ontologies: What Works and What Doesn't”
http://www.alwayson-network.com/comments.php?id=P7480_0_3_0_C
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We’ve heard all this before
In 1995 the idea that the local restaurants, the muffler shop or the bed and breakfast would have their own web site was laughable.– They would need people
to “program” HTML– They would need servers,
admins, etc.
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Semantic Web is already here
“only 642,000 documents with .rdf extension” & 9,000 .owl
Yet 20,000,000 rdf triples are accessible (DARPA)
5,000,000 FoaFnautsOracle 10.2Every Adobe 6.0 + document
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Adobe 6.0 and up
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So, what is the Semantic Web?
How do we know what anything is? – By analogy– By difference– By decomposition and description of the parts– By subsumption & categorization– By definition
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Analogy
A giant disk drive (internet)
A query engine for the internet
Surfing the web
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By Difference
Sometimes we understand things by what they are different from.
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Horseless carriage
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Wireless telegraph
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Paperless office
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Paperless …
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Human-less search interpretation
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Decomposition and description of the parts
Bicycle = frame + 2 wheels + gear train + brakes + seat + handle bars
Semantic Web = shared ontologies + tagged content + inference engines + service composition
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By subsumption and categorization
A badger is a nocturnal [categorization] omnivore [prototypical] mammal [subsumption]
The Semantic Web is a federated [prototypical] web [subsumption] with RDF tagged content [categorization]
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By definition
The Semantic Web provides a common framework that allows data to be shared and reused across application, enterprise, and community boundaries. It is a collaborative effort led by W3C with participation from a large number of researchers and industrial partners. It is based on the Resource Description Framework (RDF), which integrates a variety of applications using XML for syntax and URIs for naming.
W3C
The Semantic Web is a project that intends to create a universal medium for information exchange by giving meaning (semantics), in a manner understandable by machines, to the content of documents on the Web. Currently under the direction of its creator, Tim Berners-Lee of the World Wide Web Consortium, the Semantic Web extends the ability of the World Wide Web through the use of standards, markup languages and related processing tools.
Wikipedia
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A closer look
The power of the SW comes from a set of standards, each of which provides just a few capabilities.
What follows is the essence of what is added at each level in the standards stack, starting with those we already know and love.
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Semantic Web “Official Stack”
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Essence at each level
TCP/IP Global Physical Addressing
DNS/URL Global Logical Addressing
XML Universal Parsing
XSD Allowable Structure
RDF Assertions / Merging
RDFS Frames / Classes
OWL Inference / Reasoning
SWRL Rule Execution
March 2004
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TCP/IP
Single model for communicationGlobally unique physical addressing
216.239.37.99
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DNS and URL
Logical address need not = physical addressAllows rehosting, migration, etc.
www.google.com
DNS 216.239.37.99
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XML
Uniform parsing rules, tools, etc.Metadata (at least some of it) travels with the
data.
<book> “DaVinci Code”<author> “Dan Brown” </author>
</book>
<h1> “DaVinci Code”<p> “Dan Brown” </p>
</h1>
XML
HTML/ XHTML
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XSD
Rules about allowable XML combinationsCan verify XML validityPrimarily for creating XML, not consuming it
<xs:element name="sculpture"><xs:annotation>
<xs:documentation>Comment describing your root element</xs:documentation>
</xs:annotation></xs:element>
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RDF
Resource Description FrameworkSubject/Predicate/Object“Triple” and “Triple Store”Make assertionsMerge identities[proto truth]
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“Triples”
Subject ObjectPredicate
A URI (URL) A URI (URL) A URI (URL) or Literal
Think instances
Subject/Predicate/Object
Dave McComb Sem in Buswrote
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RDF Triples from a Database
Order2 Molson 5/12/05 Net10
Custo
mer
ID
Order3 Coors 5/12/05 Net10
Order4 Budweiser 5/12/05 Net10
Order5 Miller 5/14/05 Net10
Order1 Miller 5/12/05 Net10
Order
Date
Term
Code
Order2 CustomerID Molson
Order2 OrderDate “5/12/05”
Order2 TermCode “Net10”
Molson Molson Ale
Coors Rocky Mountain
Budweiser Clydesdales
Miller Miller Brewing
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RDF Triples from a Document
<Order> Order2 <Special Labeling> “for winterfest” </Special Labeling></Order>
Order2 Special Labeling “for winterfest”
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Simple Merge
Order2 CustomerID Molson
Order2 OrderDate “5/12/05”
Order2 TermCode “Net10”
Order2 Special Labeling “for winterfest”
Order2 CustomerID Molson
OrderDate
“5/12/05”TermCode
“Net10”
Special Labeling
“for winterfest”
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First Principles
Two thingsEqualTo the Same ThingAre EqualTo Each other
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MER1 & 2 and Spirit
MER2 is Opportunity
MER1 has APXS1
APXS1 has CalibrationSet1
Spirit is MER1
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Reification
Each Assertion (statement) has its own URIand can therefore be the Object of another Assertion
Statement 2715
Sushi sameAs RawFish
Dave thinksStmt 2715
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Reification is Useful For
VeracityProvenanceSecurity
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RDFS
RDF SchemaMeta Data for RDFAdds classes, properties, subclasses
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RDFS adds Properties
Order CustomerIDhasProperty
OrderDate
TermCode
hasPropertyhasProperty
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RDFS Subtypes
Order subTypeOf Agreement
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OWL
Web Ontology Language Comes in three flavors
– OWL Lite– OWL DL (Description Logics)– OWL Full
Adds Reasoning
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OWL DL
Necessary & sufficient
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OWL DL
Person
ParentAncestor
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SWRL
OWL + RuleML
Adds more complex reasoning and the ability to execute action
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SWRL
If y is x’s parent, and z is y’s brother, then z is x’s uncle.
parent(?x,?y) ^ brother(?y,?z) ^ uncle(?x,?z)
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Discipline
Standards
Tools
Content
Infrastructure
Tools
Part 4: Demos
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Tool: Protege
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Altova SemanticWorks
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Tool: AeroText
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Discipline
Standards
Tools
Content
Infrastructure
Infrastructure
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Infrastructure: Siderean
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Unicorn
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Semantic Web
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Essence at each level
TCP/IP Global Physical Addressing
DNS/URL Global Logical Addressing
XML Universal Parsing
XSD Allowable Structure
RDF Assertions / Merging
RDFS Frames / Classes
OWL Inference / Reasoning
SWRL Rule Execution
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Questions?
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Re cap – Objective One:
There’s much more to Semantics than good definitions
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Objective Two – Did you learn a lot of exotic terminology?
What is/are:– Semantics– Taxonomies and Ontologies– Inference– Description Logics– Classification and Reasoning – Semantic Web
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Objective Three: to pursue further
Send an email to me at [email protected]
For either a glossary of semantic terms or the “CIO’s Guide to Semantics” [I have a few bound copies]
Visit our web site, many interesting free white paperswww.semanticarts.com
Semantic Wikiwww.semanticwiki.com
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Resources – Books
“Semantics in Business Systems,” print and audio
“Semantic Web Primer” Grigoris Antoniou“The Semantic Web” Michael Daconta et
al.“Women, Fire, and Dangerous Things”
George Lakoff
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Semantic TechnologyConference
www.semantic-technology.com
March 6-9, 2006San Jose, CA
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Getting Started
“Semantic Awareness Day”
“Just Do It”
Examples
Assessment / What do you want to solve
Training
Community of Practice
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One last word
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www.semanticarts.comSemantic Arts, Inc.
