Calvin Hendryx Parker, Enabling the Semantic Web with RDF

Enabling the Semantic Web with RDF - Calvin Hendryx-Parker 06.19.2007

Enabling the Semantic Web
with RDF
Web Content 2007
Chicago

Calvin Hendryx-Parker
Six Feet Up, Inc.

Silicon Valley • Midwest
Six Feet Up, Inc. • http://www.sixfeetup.com
1


Background

• Doing RDF for nearly 4 years

• Stumbled upon it via Mozilla

• Later used to power sites like the Rosetta Project

• Still doing work using RDF and Mozilla

2


Semantic Web

• Understandable by software agents

• Find

• Share

• Integrate

• Core enabling technologies are RDF and OWL

3


Introduction to RDF

• Resource Description Framework

• Language designed to support the Semantic Web

• Neutral Format

• Directed Graph of Resources

4


RDF Basics

• Three is the magic number

• Triple made up of a 3-tuple

• Subject, Predicate, Object

• Each triple is a unique fact where the resource is
identified by a URI

5


Triples in a Graph
http://rosettaproject.org/archive/Indo-European/Indo-Iranian/Iranian/Western/Northwestern/Zaza-Gorani

lingual:isMotherOf
http://rosettaproject.org/archive/ZZZ

lin
itle gu
:T
lingual:hasLanguageCode
al
c
d :is
O
fL
an
gu
Dimli oi
dT
yp
e

lingual:Language

http://www.language-archives.org/OLAC/1.0/LanguageCodes.xsd#x-sil-ZZZ

6


URI usage in RDF
• URL is a specific instance of a URI scheme based
on a known protocol e.g. http or ftp

• URI is only an identifier and doesn't need to
resolve a location on the web

• URI examples
Using a web address
http://www.sixfeetup.com/hosting
Using a UUID version 5 of the same URL
urn:uuid:9cedb10a-84c4-5ddb-96c5-c3215fa57c21
Arbitrary URI
urn:sixfeetup:hosting

7


Serialization Formats

• RDF/XML

• N3

• N-Triples

• Turtle

8


RDF/XML
<?xml version=quot;1.0quot; encoding=quot;utf-8quot;?>
<rdf:RDF
xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'
xmlns:lingual='http://rosettaproject.org/ns/lingual/1.0/'
xmlns:dc='http://purl.org/dc/elements/1.1/'
>
<lingual:Languoid rdf:about=quot;http://rosettaproject.org/archive/gicquot;>
<lingual:hasPrimaryName>Gail</lingual:hasPrimaryName>
<dc:title>Gail</dc:title>
<lingual:hasLanguageCode>
<lingual:LanguageCode rdf:about=quot;http://www.language-archives.org/OLAC/1.0/
LanguageCodes.xsd#x-sil-gicquot;>
<lingual:hasAuthority>
<lingual:Authority rdf:about=quot;http://ethnologue.com/15/quot;>
<lingual:AuthorityIdentifier>Ethnologue15_Languages</lingual:AuthorityIdentifier>
</lingual:Authority>
</lingual:hasAuthority>
<lingual:hasCodeValue>gic</lingual:hasCodeValue>
<dc:title>Gail</dc:title>
</lingual:LanguageCode>
</lingual:hasLanguageCode>
</lingual:Languoid>
</rdf:RDF>

9


Notation3

<http://rosettaproject.org/archive/ZZZ> lingual:isOfLanguiodType lingual:Language .
<http://rosettaproject.org/archive/ZZZ> dc:title quot;Dimliquot; .

10


RDF Schemas and Web
Ontology Language (OWL)

• Provides Vocabulary

• Extended Object Class Vocabularies

• www.schemaweb.info

11


Examples of Ontology

• Beer -- http://www.purl.org/net/ontology/beer.owl
An ontology that models types of beer and
brewers/brands.

• Quaffing -- http://purl.org/net/schemas/quaffing/
An extension of the FOAF ontology to describe
who you have drank with or who you owe a
beer

12


How RDF Handles Difficult to
Describe Data
• Additional ontology can be applied via
namespaces

• Single resource visible in multiple contexts

• Allows for containment based on RDF Schema
type

• Reification

13


Reification Example
Justifies

Book C
Article B Title:
Latin
Title: Why French and
Why Spanish is a
es
Jus Italian are
ifi
t
Just
daughter of Latin
ifi e related to Latin
s
M
r

Mother
ot
he he
ot r
M

French Spanish Italian

14


RDF Applications

• FOAF -- http://rdfweb.org/foaf/

• RSS 1.0 -- http://web.resource.org/rss/1.0/

• Creative Commons -- http://creativecommons.org

• DMOZ -- http://rdf.dmoz.org/

15


Example Internal RDF Usage
• Provides more flexible queries

• Describes data that can't easily be described
using a RDBMS

• Easily extendable via namespaces

• Can be used to integrate multiple internal systems

• Feed other services such as OAI-PMH

16


Example External RDF Usage
• Data quot;mash-upquot;

• Piggy Bank

• Timelines

• Maps

• Calendar

• Graph View

17


Example External RDF Usage
• Easily allow data from 3rd party systems to mix in
with the data via namespaces

• Syndication

• Provide standardized sets of metadata about
resources

• Dublin Core

• Creative Commons

18


Use within a Content
Management System

• Rich interface to metadata

• Can be specialized to a specific domain

• Interoperability with other RDF based systems

• Expose RDF query as a service

19


Rosetta Project CMS

• An archive of all documented human languages

• Specialized Linguistic Resources and Documents

• Content and Structure is of a Contested Nature

• Geographic Boundaries Change

20


21


Many Structures, One Set of
Data
• Flat storage of languages in ZODB

• Apply many alternate structures via RDF
A
E

D
Root
B

F
C

22


Data


A B

Root C D E

F

23


Data


A C

Root D E

F B

24


25


Available tools
• RDFlib

• Multiple back-ends

• ZODB

• MySQL

• Sleepycat

• SQLite

26


Available tools
• Includes SPARQL query implementation

• Includes an Event Graph for doing operations
like indexing text

• GraphPath

• XPath style queries against RDF graphs

• Mozilla XUL

• Many others available in other languages such as
Ruby, Java, PHP and Perl
27


28


29


Example SPARQL Query
• Selecting all languages that have documents of a
specific type

SELECT ?lang
WHERE {
?doc <http://rosettaproject.org/lingbib#rosettaType> datatype .
?doc <http://rosettaproject.org/lingbib#refersToLanguoid> ?lang
}

30


Other RDF Extensions
• RDFa

• Generalized attributes in XHTML

• Currently in working draft

<div xmlns:dc=quot;http://purl.org/dc/elements/1.1/quot;
about=quot;http://www.example.com/books/wikinomicsquot;>
<span property=quot;dc:titlequot;>Wikinomics</span>
<span property=quot;dc:authorquot;>Don Tapscott</span>
<span property=quot;dc:datequot;>2006-10-01</span>
</div>

31


Questions?

Contact Info
calvin@sixfeetup.com

32

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