BYFITSUM R. LAKEW

• The semantic web is a web that is able to describe things in a way that computers can understand.

• The semantic web is not about links between web pages.

• The semantic web describes the relationships between things and the properties of things.

• The Semantic Web proposes to help computers "read" and use the Web.

• The big idea is pretty simple -- metadata added to Web pages can make the existing World Wide Web machine readable.

• Most of the web’s content today is designed for humans to read, not for computer programs to manipulate meaningfully.

• Computers have no reliable way to process the semantics.

• The Semantic Web will bring structure to the meaningful content of Web pages.

• The Semantic Web is not a separate Web but an extension of the current one.

• In semantic web information is given well-defined meaning, better enabling computers and people to work in cooperation.

• For the semantic web to function, computers must have access to structured collections of information.

• Computers must have sets of inference rules that semantic web can use to conduct automated reasoning.

• Traditional knowledge-representation systems centralized.

• Challenge of semantic web to provide a language to:

*Expresses both data and rules. *Rules to be exported onto the Web.

• Two machine – readable tools for semantic web.1. eXtensible Markup language (XML) *XML is a markup language like hypertext

markup language (HTML). *XML complements (but does not replace)

HTML by adding tags that describe data. *These tags are invisible to the people who

read the document but visible to computers. *Tags are already in use on the Web, and

existing bots. *bots that collect data for search engine, can

read them.

2. Resource Description Framework (RDF) *The RDF (Resource Description Framework) is a language for

describing information and resources on the web. *Putting information into RDF files, makes it possible for computer

programs ("web spiders") *To search, discover, pick up, collect, analyze and

process information from the web.

*The Semantic Web uses RDF to describe web resources. RDF uses triples consist of a subject, property and object. Like the

subject, verb and direct object of a sentence. In RDF, a document makes assertions that particular things . Subject and object are each identified by a Universal Resource

Identifier (URI), just as used in a link on a Web page. The verbs are also identified by URIs. The Semantic Web will enable machines to COMPREHEND semantic

documents and data, not human speech and writings.

• Ontology is a document or file that formally defines the relations among terms.

• The most typical kind of ontology for the Web has a taxonomy and a set of inference rules.

• The taxonomy defines classes of objects and relations among them.

• The meaning of terms or XML codes used on a Web page can be defined by pointers from the page to an ontology.

• Ontologies can enhance the functioning of the Web in many ways.

• Semantic web gives advantage to enter personal preferences into a computerized agent.

• An important facet of agents' functioning is the exchange of "proofs" written in the Semantic Web's unifying language.

• Agents can use digital signatures to verify that the attached information has been provided by a specific trusted source.

• The Semantic Web is more flexible, the consumer and producer agents can reach a shared understanding by exchanging ontologies.

• Semantic descriptions of device capabilities and functionality will let us achieve such automation with minimal human intervention.

Properly designed, the Semantic Web can assist the evolution of human knowledge as a whole.

• If properly designed, the Semantic Web can assist the evolution of human knowledge as a whole.

• Human endeavor is caught in an eternal tension between the effectiveness of small groups acting independently and the need to mesh with the wider community.

• A small group can innovate rapidly and efficiently, but this produces a subculture whose concepts are not understood by others.

• The Semantic Web, in naming every concept simply by a URI, lets anyone express new concepts that they invent with minimal effort.

• Its unifying logical language will enable these concepts to be progressively linked into a universal Web.

• This structure will open up the knowledge and workings of humankind to meaningful analysis by software agents, providing a new class of tools by which we can live, work and learn together.