"The Web Semantics TechnologyIntroduction Today, the data we get from the web is in the form of web pages ie., HTML documents thatare associated with one another through the use of hyperlinks. Users and computers can read suchdocuments, but extracting the meaning from them is not possible. Hence the W3C (World WideWeb consortium) has extended the concept of the web through a standard that promotes commondata formats and protocols. This led to the concept of the web semantics. Sir Tim Berners-Lee, thefather of World Wide Web, coined the term semantic web. There are two main ideas behind this.First, to associate metadata with internet resource, Metadata is bits of information about something.For example the title of a book, author, contents, date etc., Second is the ability to reason thismetadata.World Wide Web V/s Semantic web World Wide Web is a collection of documents interlinked with one another which can betransmitted from one computer to the other. Any person can contribute his/her ideas to it. Themachine simply delivers the content. The user has to assemble relevant data himself. The semantic web is an enhanced form of presenting the metadata where the computer can process the data. Thishelps the user to get collective data instead of document.Need for semantic web The main idea behind web semantics is to make information from the web widely availableto all and also to increase the effective utilization of that knowledge. Web semantic technologygives advanced options for browsing, sorting and analysing the data. Web semantic technologyrepresents data in the format which enables the machine to come to suitable decisions.So the semantic web seeks to change the landscape of the internet in a number of ways:* Making available the web of data to artificial intelligence processes (getting the web to do a bit ofthinking for users).* Encouraging companies, institutions and users to publish their data without hesitation, in an openstandard format. * Encouraging businesses to use data already present on the web.Web semantics can be understood under three phases1. Model: A scientific model describes the real life aspects in a simple manner.2. Computing:the gathered information is analysed to draw conclusions and decisions.3. Information exchange: the metadata (data within data) is shared with users.Ontology and semantics:Ontology is the formal specification of an abstract concept. It is useful for knowledge sharing andreuse. The formal representation of ontology requires modelling. Two types of models arementioned here. i. Frame-based model: This uses frames, slots and facets as elements. The frame can represent anyentity in a domain. A class frame represents a class and an individual frame represents anindividual. One frame can inherit the properties of the other. Each frame has slot value. The frames,slots are given standard names depending on frequently used entities.ii. Semantic network model: This is a graph, where vertices represent concepts and edges representthe relation between them. Semantic network expresses vocabulary that is helpful especially forhuman, but that still can be used for machine processing.The relations between concepts that are used in semantic networks are as follows:? synonym - entity A expresses the same thing as entity B? antonym - entity A expresses the opposite of entity B? meronym, holonym- part-ofrelation between concepts? hyponym, hypernym - the inclusion of semantic range between concepts in both directions.The Web Semantics Architecture fig:Architecture of semantic webThe first layer consists of URI and Unicode which inherit the important features of World WideWeb. Unicode is a standard for encoding international character sets and it enables all humanlanguages to be used (written and read) on the web using one standardized form. Uniform ResourceIdentifier (URI)is a string of a standardised form that allows to uniquely identify resources (e.g.,documents). A subset of URI is Uniform Resource Locator (URL), which has mechanism for dataaccess and a (network) location of a document.Extensible Markup Language (XML) forms the next layer which ensures common syntax in thesemantic web. To represent the metadata in core format we use the information in graphical format.RDF is a standard model for data interchange on the Web. RDF has features that enable merging thedata even if the underlying schemas differ, and it supports the evolution of schemas withoutrequiring all the data users to be changed.RDF extends the linking structure of the Web to use URIs to name the relationship between thingsand two ends of the link (this is referred to as a “triple”). Using this simple model, it allowsstructured and partially structured data to be mixed, published, and shared across differentapplications.This linking structure forms a graph with label and direction, where the edges represent the namedlink between two resources, represented by the nodes of a graph. This graph view is the simplestpossible model formed in mind for RDF and is often used in simplified visual explanations. RDFSchema is available to create lightweight ontologies. Unlike HTML and XML this allows furtherprocessing and recombination of data. "