Semantic Web and Metadata

Note: Social site users, geeks or IT entrepreneurs will have something to take away after reading this blog.

Before viewing the four videos below that introduce Semantic Web, what is semantic web?

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.

The Semantic Web is a Web of data. There is a lot of data we all use every day, and it’s not part of the Web. For example, I can see my bank statements on the web, and my photographs, and I can see my appointments in a calendar. But can I see my photos in a calendar to see what I was doing when I took them? Can I see bank statement lines in a calendar? Why not? Because we don’t have a web of data. Because data is controlled by applications, and each application keeps it to itself.

The vision of the Semantic Web is to extend principles of the Web from documents to data. Data should be accessed using the general Web architecture using, e.g., URI-s; data should be related to one another just as documents (or portions of documents) are already. This also means creation of a common framework that allows data to be shared and reused across application, enterprise, and community boundaries, to be processed automatically by tools as well as manually, including revealing possible new relationships among pieces of data.

Semantic Web technologies can be used in a variety of application areas; for example: in data integration, whereby data in various locations and various formats can be integrated in one, seamless application; in resource discovery and classification to provide better, domain specific search engine capabilities; in cataloging for describing the content and content relationships available at a particular Web site, page, or digital library; by intelligent software agents to facilitate knowledge sharing and exchange; in content rating; in describing collections of pages that represent a single logical “document”; for describing intellectual property rights of Web pages (see, eg, the Creative Commons), and in many others.

The Semantic Web is an evolving extension of the World Wide Web in which the semantics of information and services on the web is defined, making it possible for the web to understand and satisfy the requests of people and machines to use the web content. It derives from World Wide Web Consortium director Sir Tim Berners-Lee’s vision of the Web as a universal medium for data, information, and knowledge exchange.

At its core, the semantic web comprises a set of design principles, collaborative working groups, and a variety of enabling technologies. Some elements of the semantic web are expressed as prospective future possibilities that are yet to be implemented or realized. Other elements of the semantic web are expressed in formal specifications. Some of these include Resource Description Framework (RDF), a variety of data interchange formats (e.g. RDF/XML, N3, Turtle, N-Triples), and notations such as RDF Schema (RDFS) and the Web Ontology Language (OWL), all of which are intended to provide a formal description of concepts, terms, and relationships within a given knowledge domain.

Video #1: Eric Schmidt, Chairman and CEO of Google, on Web 2.0 and Web 3.0

Transcript by MQIT Corporation

Easy question.
What is Web 3.0?
We know what is Web 2.0 is.
What has Google see Web 3.0 ought to be?

Well, Web 2.0 is a marketing term.
And I think you just invented Web 3.0.
But if I were to guess what Web 2.0 is.
I would tell you that it is a different way of building an applications.
Up until now Web 2.0 has been a term that corresponds to something called AJAX.
AJAX is a computer architecture that is the underlaying architecture that I have been talking about.
And my prediction is would be that Web 3.0 will be ultimately be seen.
As applications that are piece together.
A number of characteristics.
Application are relatively small.
The data is in the cloud.
The applications can run on any device, PC or mobile phone.
That the applications are very fast.
And that they are very customizable.
And further more the applications are distributed by virus.
Essentially virally, literally by social networks, by email.
You will not go to the store to purchase them.
You will say – I send to you.
Here is a new interesting way of doing one thing or another.
That is a very different application model than we have ever seen in computing.
Very different from the mainframe era.
Very different from the PC industry.
Much likely to be very very large.
Has low variance entry.
The new generation of tools that is being announce today.
Google and other companies make it relatively easy to do.
Solves a lot of problem.
And works everywhere.

Video #2: Tim Berners-Lee, Inventor of WWW and Director of W3C, on the Semantic Web

Video #3: Introduction to Semantic Web from Digital Bazaar

Video #4: Semantic Web from GoogleTalks and DERI

The Semantic Web is a field aiming a the creation, deployment, and interoperation of machine readable data on the Internet. In the talk we present some projects in DERI on Semantic Web technologies – notably Semantic Interlinking of Online Community sites, Social Semantic Collaborative Filtering, and ActiveRDF, a library for Browsing, programming and navigating Semantic Web data.

The SIOC (Semantic Interlinking of Online Communities) project is an effort aiming at establishing and deploying a metadata vocabulary for interlinking and connecting distributed conversation on blogs, bulletin boards, and mailing lists. The vocabulary has been implemented…

Some of the technologies and projects mentioned in the videos above.

RDFa, Resource Description Framework in attribute
Today’s web is built predominantly for human consumption. Even as machine-readable data begins to appear on the web, it is typically distributed in a separate file, with a separate format, and very limited correspondence between the human and machine versions. As a result, web browsers can provide only minimal assistance to humans in parsing and processing web data: browsers only see presentation information. We introduce RDFa, which provides a set of XHTML attributes to augment visual data with machine-readable hints. We show how to express simple and more complex datasets using RDFa, and in particular how to turn the existing human-visible text and links into machine-readable data without repeating content.

Microformats
Designed for humans first and machines second, microformats are a set of simple, open data formats built upon existing and widely adopted standards. Instead of throwing away what works today, microformats intend to solve simpler problems first by adapting to current behaviors and usage patterns (e.g. XHTML, blogging).

Operator
Operator leverages microformats and other semantic data that are already available on many web pages to provide new ways to interact with web services.

SIOC, Semantic-Interlinked Online Communities
What is SIOC? The SIOC initiative (Semantically-Interlinked Online Communities) aims to enable the integration of online community information. SIOC provides a Semantic Web ontology for representing rich data from the Social Web in RDF. It has recently achieved significant adoption through its usage in a variety of commercial and open-source software applications, and is commonly used in conjunction with the FOAF vocabulary for expressing personal profile and social networking information. By becoming a standard way for expressing user-generated content from such sites, SIOC enables new kinds of usage scenarios for online community site data, and allows innovative semantic applications to be built on top of the existing Social Web. The SIOC ontology was recently published as a W3C Member Submission, which was submitted by 16 organisations.

OWL, Web Ontology Language
The World Wide Web as it is currently constituted resembles a poorly mapped geography. Our insight into the documents and capabilities available are based on keyword searches, abetted by clever use of document connectivity and usage patterns. The sheer mass of this data is unmanageable without powerful tool support. In order to map this terrain more precisely, computational agents require machine-readable descriptions of the content and capabilities of Web accessible resources. These descriptions must be in addition to the human-readable versions of that information. The OWL Web Ontology Language is intended to provide a language that can be used to describe the classes and relations between them that are inherent in Web documents and applications.

ActiveRDF
ActiveRDF is a library for accessing RDF data from Ruby programs. It can be used as data layer in Ruby-on-Rails, in the same way as you can use ActiveRecord for accessing relational databases. Using ActiveRDF with Ruby-on-Rails allows you to create semantic web applications very rapidly. ActiveRDF gives you a domain specific language for your RDF model: you can address RDF resources, classes, properties, etc. programmatically, without queries.

SSCF / SIOC Support
This project delivers a number of components that combined together allow users to search and browse the information space using existing semantic relations and social annotations.

The three first components (partially refactored from FOAFRealm and JeromeDL projects) are:
* SSCF – Social Semantic Collaborative Filtering
* MBB – MultiBeeBrowse – a modern faceted navigation
* SQE – Semantic Query Expansion based on a community-aware user profile

JeromeDL
JeromeDL is a Social Semantic Digital Library. As a digital library, it allows institutions to easily publish documents on the Web. It supports a variety of document formats and allows to store and query a rich bibliographic description of each document.

FoaF, Friend of a Friend
Our goal is to design and implement D-FOAF, a distributed authentication and trust infrastructure without a centralised authority. D-FOAF will be a backbone for trust applications based on social relationships and will establish idenity of users similar to the way we establish identity and trust in real life. D-FOAF will be based on previous work like the P2P HyperCuP topology and FOAFRealm, a Semantic Web based user and relationship management system. Implementation work will be conducted for the J2EE, .NET and PHP environments.

SKOS, Simple Knowledge Organization System

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