What is the semantic web? [closed]

Answer 1

The Semantic Web is just that - a Semantic (meaningful) layer on top of the WWW. It is semi structured (RDF), it is self-describing (ontologies using OWL), and allows resource discovery (SPARQL).

The Semantic Web works on the premise of the "Open World" assumption; just because something is not stated doesn't mean it doesn't exist, it is simply "unknown". This is a fundamentally different logic to that used in an RDBMS like MySQL et al. - if something is missing it doesn't exist - "Closed World" assumption. Prolog and DATALOG are good examples of Close World logics.

If you want to really learn what is happening underneath, you'll need to look at its foundations, which lie in Description Logic. A good overview of the Description Logic can be found here: http://www.inf.unibz.it/~franconi/dl/course/

If you want to learn more about RDF, read the RDF Primer. RDF Semantics is another rip-roaring read.

Researchers have basically given up on the "Semantic" part of the Semantic Web and decided to focus on Linked Data - how RDF triples can be navigated so that we can waste more Internet bandwidth ;-)

Answer 2

Semantic web is the only pragmatic solution proposed so far to repair inherent design flaws of World Wide Web. Because the designers of the internet, as we know it today, did not provide mechanisms which would address fundamental linguistic phenomenons which govern the way humans think and communicate such as homonymy, synonymy etc. searching for information on the internet results in a flood of false positives. The idea of semantic web boils down to assigning unequivocal identifiers to web resources which will help identify their meaning correctly. If it succeeds one day we may forget what the usual google search looked like, if it fails all will remain as it is now.

Answer 3

How will it be different to the web we know now?

Right now the HTML+CSS is centered more on structure and presentation. Semantics is about the meaning of the information. In semantic web you use shared ontologies to establish meaning (semantic) of the object and meaning of relations between the objects. Best known ontologies are: FOAF and Dublin Core.

Typically semantics would be expressed in specialized language, such as RDF or OWL. RDF can be embedded within XHTML using eRDF or W3C's RDFa.

Less structured alternative to eRDF/RDFa are microformats.

Read more at: http://en.wikipedia.org/wiki/Semantic_web

Answer 4

The Semantic Web is a distributed information system where interlinked data is published as RDF triples over HTTP. RDF triples consist of subject, predicate and object but can have other things attached to them such as datatypes and annotations about the natural language of objects. On the Semantic Web, URIs are used both as identifiers and as addresses of network resources.

It’s different from the Web, because the Web is a distributed information system of documents and application interfaces.

Answer 5

Tim Berners-Lee describes it in his blog post Giant Global Graph (from 2007-11-21):

Three mental moves:

1. Internet: "It isn't the cables, it is the computers which are interesting"
2. (World Wide) Web: "It isn't the computers, but the documents which are interesting"
3. Giant Global Graph: "It's not the documents, it is the things they are about which are important"

About the term "Giant Global Graph":

We can use the word Graph, now, to distinguish from Web.

I called this graph the Semantic Web, but maybe it should have been Giant Global Graph! Any worse than WWWW? ;-) Not the "Semantic Web" term has been established for a long time, I'm not proposing to change it. But let's think about the graph which it is. (Footnote: "Graph" also happens to be the word the RDF specifications use, but that is by the way. While an XML parser creates a DOM tree, an RDF parser creates an RDF graph in memory.)

Answer 6

The Semantic Web is what Tim Berners-Lee, the inventor of the World Wide Web, really intended the Web to be—that is, a global graph of interlinked data. It is a generalization of a social graph, where you can use social data (with vocabularies like FOAF) as well as any other kind of machine-understandable data and connect them to each other. The standard formats for describing this infortmation to machines is the Resource Description Format (RDF) and the Web Ontology Language (OWL). There's already a lot of encoded data on the Web, including an RDF version of Wikipedia, called DBPedia.

The Semantic Web will be different than today's Web in that computers as well as humans will understand what documents contain as well as what the significance of the links between documents are. This will facilitate automation of information-processing tasks, including researching information from trustworthy sources. The full SemWeb stack includes cryptography, proof systems, and trust networks.