Semantic Web

The Semantic Web is a collaborative movement led by the World Wide Web Consortium (W3C) that promotes accepted formats for abstracts on the World Wide Web. By auspicious the admittance of semantic agreeable in web pages, the Semantic Web aims at converting the accepted web of baggy abstracts into a "web of data". It builds on the W3C's Resource Description Framework (RDF).1

According to the W3C, "The Semantic Web provides a accepted framework that allows abstracts to be aggregate and reused beyond application, enterprise, and association boundaries."1

The appellation was coined by Tim Berners-Lee,2 the artist of the World Wide Web and administrator of the World Wide Web Consortium ("W3C"), which oversees the development of proposed Semantic Web standards. He defines the Semantic Web as "a web of abstracts that can be candy anon and alongside by machines."

While its critics accept questioned its feasibility, proponents altercate that applications in industry, analysis and animal sciences analysis accept already accurate the authority of the aboriginal concept.3not in commendation given

History

The abstraction of the Semantic Arrangement Model was coined in the aboriginal sixties by the cerebral scientist Allan M. Collins, linguist M. Ross Quillian and analyst Elizabeth F. Loftus in assorted publications,45677 as a anatomy to represent semantically structured knowledge. It extends the arrangement of hyperlinked human-readable web pages by inserting machine-readable metadata about pages and how they are accompanying to anniversary other, enabling automatic agents to admission the Web added intelligently and accomplish tasks on account of users. The appellation was coined by Tim Berners-Lee,8 the artist of the World Wide Web and administrator of the World Wide Web Consortium ("W3C"), which oversees the development of proposed Semantic Web standards. He defines the Semantic Web as "a web of abstracts that can be candy anon and alongside by machines."

Many of the technologies proposed by the W3C already existed afore they were positioned beneath the W3C umbrella. These are acclimated in assorted contexts, decidedly those ambidextrous with advice that encompasses a bound and authentic domain, and area administration abstracts is a accepted necessity, such as accurate analysis or abstracts barter amid businesses. In addition, added technologies with agnate goals accept emerged, such as microformats.

Purpose

The capital purpose of the Semantic Web is active the change of the accepted Web by enabling users to find, share, and amalgamate advice added easily. Bodies are able of appliance the Web to backpack out tasks such as award the Irish chat for "folder", reserving a library book, and analytic for the everyman amount for a DVD. However, machines cannot achieve all of these tasks after animal direction, because web pages are advised to be apprehend by people, not machines. The semantic web is a eyes of advice that can be readily interpreted by machines, so machines can accomplish added of the annoying assignment circuitous in finding, combining, and acting aloft advice on the web.

The Semantic Web, as originally envisioned, is a arrangement that enables machines to "understand" and acknowledge to circuitous animal requests based on their meaning. Such an "understanding" requires that the accordant advice sources is semantically structured, a arduous task.

Tim Berners-Lee originally bidding the eyes of the Semantic Web as follows:9

I accept a dream for the Web in which computers become able of allegory all the abstracts on the Web – the content, links, and affairs amid bodies and computers. A ‘Semantic Web’, which should accomplish this possible, has yet to emerge, but back it does, the circadian mechanisms of trade, authority and our circadian lives will be handled by machines talking to machines. The ‘intelligent agents’ bodies accept accustomed for ages will assuredly materialize.

The Semantic Web is admired as an integrator beyond altered content, advice applications and systems. It has applications in publishing, blogging, and abounding added areas.

Often the agreement "semantics", "metadata", "ontologies" and "Semantic Web" are acclimated inconsistently. In particular, these agreement are acclimated as accustomed analogue by advisers and practitioners, spanning a all-inclusive mural of altered fields, technologies, concepts and appliance areas. Furthermore, there is abashing with attention to the accepted cachet of the enabling technologies envisioned to apprehend the Semantic Web. In a cardboard presented by Gerber, Barnard and Van der Merwe10 the Semantic Web mural is charted and a abrupt approximate of accompanying agreement and enabling technologies is presented. The architectural archetypal proposed by Tim Berners-Lee is acclimated as base to present a cachet archetypal that reflects accepted and arising technologies.11

edit Limitations of HTML

Many files on a archetypal computer can be about disconnected into animal clear abstracts and apparatus clear data. Abstracts like mail messages, reports, and brochures are apprehend by humans. Data, like calendars, addressbooks, playlists, and spreadsheets are presented appliance an appliance affairs which lets them be viewed, searched and accumulated in altered ways.

Currently, the World Wide Web is based mainly on abstracts accounting in Hypertext Markup Language (HTML), a markup assemblage that is acclimated for coding a anatomy of argument interspersed with multimedia altar such as images and alternate forms. Metadata tags accommodate a adjustment by which computers can categorise the agreeable of web pages, for example:

With HTML and a apparatus to cede it (perhaps web browser software, conceivably addition user agent), one can actualize and present a folio that lists items for sale. The HTML of this archive folio can accomplish simple, document-level assertions such as "this document's appellation is 'Widget Superstore'", but there is no adequacy aural the HTML itself to advance actually that, for example, account cardinal X586172 is an Acme Gizmo with a retail amount of €199, or that it is a customer product. Rather, HTML can alone say that the amount of argument "X586172" is article that should be positioned abreast "Acme Gizmo" and "€199", etc. There is no way to say "this is a catalog" or alike to authorize that "Acme Gizmo" is a affectionate of appellation or that "€199" is a price. There is additionally no way to accurate that these pieces of advice are apprenticed calm in anecdotic a detached item, audible from added items conceivably listed on the page.

Semantic HTML refers to the acceptable HTML convenance of markup afterward intention, rather than allegorical blueprint capacity directly. For example, the use of cogent "emphasis" rather than , which specifies italics. Blueprint capacity are larboard up to the browser, in aggregate with Cascading Style Sheets. But this convenance avalanche abbreviate of allegorical the semantics of altar such as items for auction or prices.

Microformats represent actionable attempts to extend HTML syntax to actualize machine-readable semantic markup about altar such as retail food and items for sale.

edit Semantic Web solutions

The Semantic Web takes the band-aid further. It involves publishing in languages accurately advised for data: Resource Description Framework (RDF), Web Ontology Language (OWL), and Extensible Markup Language (XML). HTML describes abstracts and the links amid them. RDF, OWL, and XML, by contrast, can call approximate things such as people, meetings, or aeroplane parts.

These technologies are accumulated in adjustment to accommodate descriptions that supplement or alter the agreeable of Web documents. Thus, agreeable may apparent itself as anecdotic abstracts stored in Web-accessible databases,12 or as markup aural abstracts (particularly, in Extensible HTML (XHTML) interspersed with XML, or, added often, absolutely in XML, with blueprint or apprehension cues stored separately). The machine-readable descriptions accredit agreeable managers to add acceptation to the content, i.e., to call the anatomy of the ability we accept about that content. In this way, a apparatus can action ability itself, instead of text, appliance processes agnate to animal deductive acumen and inference, thereby accepting added allusive after-effects and allowance computers to accomplish automatic advice acquisition and research.

An archetype of a tag that would be acclimated in a non-semantic web page:

Examples

When we allocution about the Semantic Web, we allege about abounding "howto’s" which are generally incomprehensible because the appropriate notions of linguistics are actual generally abandoned by best people. Thus, we are activity to rather brainstorm what is activity to attending like the approaching with the actualization of the Semantic Web.

edit Meta-Wiki

The sites of Wiki blazon soar. Their administrations and their objectives can be actual different. These wikis are added and added specialized. But best of wikis absolute the chase engines to basis them because these chase engines abatement the wikis' ability and almanac pages which are obsolete, by definition, alfresco the wiki (perpetual update). Meta- search-engines are activity to accumulated the acquired aftereffect by requesting alone at anniversary of these wikis. The wikis become silos of attainable abstracts for appointment by bodies and machines through admission credibility (triplestore).

edit Semantic detectives & Semantic identity

The adolescent bloggers are now on the labour market. The companies do not ask any best for the administrative book of a fresh employee. To acquire information, the companies abode in a analytical way to engines which are activity to catechize all the sites which advertence and basis the attainable advice on the Web. The adverse amid chase engines is activity to affair the accommodation to acknowledge at requests area the faculty is activity to booty added and added accent (evolution of the requests with keywords appear the semantic requests). There will be three types of person: the unknown, the "without splash" and the others. The others will acquire to abolish in a analytical way the advice which could backpack disadvantages and which will be added and added accessible. It will be the aforementioned engines of semantic chase which additionally allegation this service.

edit Contour Privacy/Consumer/Public

The Web's accouchement became parents. They use accoutrement which can absolute the admission and the overextension of the advice by their children. So, the parents can see at any time the web's logs of their accouchement but they additionally acquire a net which is activity to analyze their "private" character afore it is broadcasted on the network. For example, a third-part assurance entity, forth with their adaptable blast provider, the column appointment and the bank, will acquire the consumer’s character so as to affectation the abode of commitment and the acquittal of this consumer. A attainable character additionally exists to beforehand a resume (CV), a blog or an avatar for archetype but the abstracts abide the acreage of the buyer of the server who hosts this data. So, the adaptable blast provider offers a claimed server who will accommodate one attainable area who will automatically be affected on the arrangement afterwards every modification. If I appetite that my resume is not any best on the network, I aloof acquire to abolish it of my attainable area from my server. So, the adaptable blast provider creates a controllable silo of advice for every attainable profile.

edit Claimed agent

In a few years, the aftermost bearing of apprentice is now adaptable and transcribes the animal voice. However, it has to alteration the semantic estimation to added able computers. These servers can so adapt the faculty of simple sentences and catechize added servers to account the acknowledgment to be given. Example: "Arthur alternate at him. He ordered a pizza by his claimed agenda agent. His abettor is activity to accelerate the advice to the home server which will acquire or not the purchase. It refuses because it accustomed the adjustment of the Arthur's parents to shop for alone a composed menu. So, the home server displays on the TV3D the accustomed airheaded to acquiesce Arthur to accept a fresh meal."

edit Research assistant

In 20??, the Semantic Web is now a reality. Marc is a researcher. He has a fresh idea. He is activity to analyze it with his agenda abettor which is anon activity to appearance him the chaos of his affirmation by application the attainable ability in silos on the Web. Marc will be able to adapt his acumen or to acquisition the proofs which authenticate that the absolute ability is apocryphal and so to beforehand the accurate ability aural the Semantic Web

Challenges

Some of the challenges for the Semantic Web accommodate vastness, vagueness, uncertainty, inconsistency, and deceit. Automatic acumen systems will accept to accord with all of these issues in adjustment to bear on the swear of the Semantic Web.

Vastness: The World Wide Web contains abounding billions of pages. The SNOMED CT medical analogue aesthetics abandoned contains 370,000 chic names, and absolute technology has not yet been able to annihilate all semantically bifold terms. Any automatic acumen arrangement will accept to accord with absolutely huge inputs.

Vagueness: These are estimated concepts like "young" or "tall". This arises from the vagueness of user queries, of concepts represented by agreeable providers, of analogous concern agreement to provider agreement and of aggravating to amalgamate altered ability bases with overlapping but cautiously altered concepts. Fuzzy argumentation is the best accepted abode for ambidextrous with vagueness.

Uncertainty: These are absolute concepts with ambiguous values. For example, a accommodating ability present a set of affection which accord to a cardinal of altered audible diagnoses anniversary with a altered probability. Probabilistic acumen techniques are about alive to abode uncertainty.

Inconsistency: These are analytic contradictions which will accordingly appear during the development of ample ontologies, and back ontologies from abstracted sources are combined. Deductive acumen fails catastrophically back faced with inconsistency, because "anything follows from a contradiction". Defeasible acumen and paraconsistent acumen are two techniques which can be alive to accord with inconsistency.

Deceit: This is back the ambassador of the advice is carefully ambiguous the customer of the information. Cryptography techniques are currently activated to allay this threat.

This account of challenges is allegorical rather than exhaustive, and it focuses on the challenges to the "unifying logic" and "proof" layers of the Semantic Web. The World Wide Web Consortium (W3C) Incubator Group for Ambiguity Acumen for the World Wide Web (URW3-XG) final address chastening these problems calm beneath the distinct branch of "uncertainty". Abounding of the techniques mentioned actuality will crave extensions to the Web Aesthetics Accent (OWL) for archetype to comment codicillary probabilities. This is an breadth of alive research.14

edit Standards

Standardization for Semantic Web in the ambience of Web 3.0 is beneath the affliction of W3C.15

edit Components

The appellation "Semantic Web" is generally acclimated added accurately to accredit to the formats and technologies that accredit it.1 The collection, alignment and accretion of affiliated abstracts are enabled by technologies that accommodate a academic description of concepts, terms, and relationships aural a accustomed ability domain. These technologies are defined as W3C standards and include:

Resource Description Framework (RDF), a accepted adjustment for anecdotic information

RDF Schema (RDFS)

Simple Ability Organization Arrangement (SKOS)

SPARQL, an RDF concern language

Notation3 (N3), advised with human-readability in mind

N-Triples, a architectonics for autumn and transmitting data

Turtle (Terse RDF Triple Language)

Web Aesthetics Accent (OWL), a ancestors of ability representation languages

The Semantic Web Stack.

The Semantic Web Stack illustrates the architectonics of the Semantic Web. The functions and relationships of the apparatus can be abbreviated as follows:16

XML provides an basal syntax for agreeable anatomy aural documents, yet assembly no semantics with the acceptation of the agreeable independent within. XML is not at present a all-important basic of Semantic Web technologies in best cases, as another syntaxes exists, such as Turtle. Turtle is a de facto standard, but has not been through a academic acclimation process.

XML Schema is a accent for accouterment and akin the anatomy and agreeable of elements independent aural XML documents.

RDF is a simple accent for cogent abstracts models, which accredit to altar ("resources") and their relationships. An RDF-based archetypal can be represented in a array of syntaxes, e.g., RDF/XML, N3, Turtle, and RDFa.17 RDF is a axiological accepted of the Semantic Web.181920

RDF Schema extends RDF and is a cant for anecdotic backdrop and classes of RDF-based resources, with semantics for generalized-hierarchies of such backdrop and classes.

OWL adds added cant for anecdotic backdrop and classes: amid others, relations amid classes (e.g. disjointness), cardinality (e.g. "exactly one"), equality, richer accounting of properties, characteristics of backdrop (e.g. symmetry), and abundant classes.

SPARQL is a agreement and concern accent for semantic web abstracts sources.

edit Current accompaniment of standardization

Currentas of? advancing standardizations include:

Rule Interchange Architectonics (RIF) as the Rule Layer of the Semantic Web Stack

Not yet absolutely accomplished layers include:

Unifying Argumentation and Proof layers are ability alive research.

The absorbed is to enhance the account and account of the Web and its commutual assets through:

Servers which betrayal absolute abstracts systems application the RDF and SPARQL standards. Abounding converters to RDF abide from altered applications. Relational databases are an important source. The semantic web server attaches to the absolute arrangement after affecting its operation.

Abstracts "marked up" with semantic advice (an addendum of the HTML tags acclimated in today's Web pages to accumulation advice for Web chase engines application web crawlers). This could be machine-understandable advice about the human-understandable agreeable of the certificate (such as the creator, title, description, etc., of the document) or it could be absolutely metadata apery a set of facts (such as assets and casework abroad in the site). (Note that annihilation that can be articular with a Uniform Resource Identifier (URI) can be described, so the semantic web can acumen about animals, people, places, ideas, etc.) Semantic markup is generally generated automatically, rather than manually.

Accepted metadata vocabularies (ontologies) and maps amid vocabularies that acquiesce certificate creators to apperceive how to mark up their abstracts so that agents can use the advice in the supplied metadata (so that Author in the faculty of 'the Author of the page' won't be abashed with Author in the faculty of a book that is the accountable of a book review).

Automatic agents to accomplish tasks for users of the semantic web application this data

Web-based casework (often with agents of their own) to accumulation advice accurately to agents (for example, a Trust account that an abettor could ask if some online abundance has a history of poor account or spamming)