The document discusses the Semantic Web and how meaning is represented through RDF triples. It explains that semantics deals with meaning, and gives examples of how RDF represents relationships between resources using a subject, predicate, and object. It also discusses FOAF (Friend of a Friend) as a vocabulary used to describe people and relationships on the Semantic Web through RDF triples.

1. Also Known as Web 3.0
The Web of Tomorrow is here today.
Presented by Bruce Whealton: Future Wave
Designs: http://FutureWaveDesigns.com 1

2. Syntax Versus Semantics
 Syntax is like the rules of grammar, and how we order
our words… or in terms of computers it deals with the
format and structure of commands or how we give
commands to a computer.
 Semantics deals with meaning.
Presented by Bruce Whealton: Future Wave
Designs: http://FutureWaveDesigns.com 2

3. Representing Meaning
 RDF: Resource Descriptive Framework
 Everything is a resource
 Data/Information/Knowledge is represented as triples:
Subject – Predicate – Object
 RDF is also a file format. An example that will be
presented below is a foaf file: foaf.rdf
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4. Meaning represented as triples
 Bruce knows Jean
 Person1 first_name Bruce
 Person1 last_name Whealton
 Similar to saying Person1 hasFirstName (has a first
name of) Bruce
Presented by Bruce Whealton: Future Wave
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5. Address book Graph
P1 Knows Jean
First
name Bruce
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6. FOAF – Friend of a Friend
 A Semantic Web Vocabulary used to describe people,
their activities and their relationships to one another.
 It is becoming very popular for people who discover
this to setup and have their own FOAF profile.
 This vocabulary is the base from which other
vocabularies are extended.
 So, what is a vocabulary in this context?
Presented by Bruce Whealton: Future Wave
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7. Semantic Web Vocabularies and
Ontologies
 For the Semantic Web we deal with controlled
vocabularies, which define terms and how they relate
to each other.
 We have a hierarchy of Classes which each have
properties.
 This is where you get the triples which relate the
classes to the values of these properties.
 Let’s take some examples…
Presented by Bruce Whealton: Future Wave
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8.  A Person “has name” “Bruce Whealton”
 Person is a class and “has name” is the predicate with
“Bruce Whealton” being the value
Presented by Bruce Whealton: Future Wave
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9. Continuing with Vocabularies
 We use a vocabulary to describe concepts that relate to
a specific domain, or an area of knowledge… or simply
toa set of concepts.
 Different fields and professions have their own
vocabulary.
 We need to define how the terms we want to use relate
to one another.
 This is how we express meaning on the semantic web;
 And form Semantic Web databases – aka Triple Stores
Presented by Bruce Whealton: Future Wave
Designs: http://FutureWaveDesigns.com 9

10. Continuing with FOAF
 FOAF concepts are prefixed with the letters foaf.
 Examples: foaf:Person is a class which describes a
person.
 foaf:name is a property
 foaf:Person foaf:name “Bruce Whealton”
 A triple
 Much more can be represented with this vocabulary,
such as chat ids, web pages, weblogs;
 One of the most important things is who you know.
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11. foaf:knows
 Using this property web crawlers can discover foaf
profiles by crawling from one profile to the next.
 Each foaf profile will have links to the people that one
knows along with links to web pages that describe
those people, e.g. their foaf profile.
 Web crawlers follow those links…
 You build your network through the links within your
foaf profile and the links to you in other profiles.
 Your foaf profile is stored in a file, typically, in RDF
format which was described earlier in this
presentation, i.e. foaf.rdf
Presented by Bruce Whealton: Future Wave
Designs: http://FutureWaveDesigns.com 11