SemanticWebFaq - ESW Wiki

Some frequently asked questions about the SemanticWeb:

What is the Semantic Web?

The Semantic Web is a web of computer-readable data.
Think of a bar-code on a Cereal Box: You can read the text on the cereal box, but a computer can read the bar code. The Semantic Web is like the bar code. (SemanticWebCerealBox.)
Read "SemanticWeb" for more information.

What is the Semantic Web Activity at W3C?

It comprises the RDF Core Working Group, the Web Ontology Working Group, the RDF Interest Group, and the Semantic Web Coordination Group, plus an AdvancedDevelopment component. see W3C Semantic Web

Are there any books on the Semantic Web?

Weaving the Web, 1999 by Tim Berners-Lee introduces the concept.
Spinning the Semantic Web, 2003 is a recent collection of (mostly older) papers about the Semantic Web - Tim Berners-Lee wrote a foreward.
an Amazon list of books related to Semantic Web and similar topics is maintained by Nova Spivack

Are there any Semantic Web tutorials?

Semantic Web Tutorial Using N3 was given by Berners-Lee, Connolly and Hawke at WWW2003. The materials include text and slides.
see also: OwlTalks
Semantic Web Tutorial: RDF, RDFS, SPARQL using CORESE

Are there any published articles on the Semantic Web?

The Semantic Web, Berners-Lee, Hendler, Lassila, May 2001

What might one use ontologies for?

see OWL Use Cases and Requirements Use cases: Web portal, Multimedia collections, Corporate web site management, Design documentation, Agents and services, Ubiquitous computing

Where are ontologies already used right now?

What is the difference between an ontology and a schema?

CleanMe
From http://www.w3.org/2001/sw/WebOnt/diffs/owl-guide.html One question that comes up when describing yet another XML/Web standard is "What does this buy me that XML and XML Schema don't?" There are two answers to this question.
An ontology differs from an XML schema in that it is a knowledge representation, not a message format. Most industry based Web standards consist of a combination of message formats and protocol specifications. These formats have been given an operational semantics, such as, "Upon receipt of this PurchaseOrder message, transfer Amount dollars from AccountFrom to AccountTo and ship Product." But the specification is not designed to support reasoning outside the transaction context. For example, we won't in general have a mechanism to conclude that because the Product is a type of Chardonnay it must also be a white wine. One advantage of OWL ontologies will be the availability of tools that can reason about them. Tools will provide generic support that is not specific to the particular subject domain, which would be the case if one were to build a system to reason about a specific industry-standard XML schema. Building a sound and useful reasoning system is not a simple effort. Constructing an ontology is much more tractable. It is our expectation that many groups will embark on ontology construction. They will benefit from third party tools based on the formal properties of the OWL language, tools that will deliver an assortment of capabilities that most organizations would be hard pressed to duplicate.
From http://lsdis.cs.uga.edu/~cartic/SemWeb/dbai.ppt Real world schemas don't come in trees In real schemas elements/nodes are interconnected by three types of relationships:
- Containment: has delete propagation semantics
- Aggregation
- IsDerivedFrom abstracts IsA and IsTypeOf relationships to model shared type information.
Ontologies can have any kinds of relationship types. These relationships can be subclassed.
Ontologies may contain at the same time the data layout and data instances. (?)

What are vocabularies? What's the difference between XML, RDF, and OWL vocabularies?

Why should I bother to model an OWL ontology? Isn't this just a hype/sport right now?