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Semantic Web

Semantic Web. Quratulain Rajput Faculty of Computer Science, IBA Spring2013. Growth of internet. World Wide Web. World Wide Web. From web 1.0 to web 2.0. Interactive participation. Information production. Blog,wiki,social -media-sites. Information access. Information link with href.

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Semantic Web

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  1. Semantic Web Quratulain Rajput Faculty of Computer Science, IBA Spring2013

  2. Growth of internet Quratulain Rajput

  3. World Wide Web Quratulain Rajput

  4. World Wide Web • From web 1.0 to web 2.0 Interactive participation Information production • Blog,wiki,social-media-sites Information access Information link with href Quratulain Rajput

  5. How big is the web? • Google just released some astounding figures about the size of the Web. According to a blog post on the Official Google Blog, the Google index contained 26 million pages in 1998. By 2000, the index reached the one billion mark, and just recently, Google hit a new milestone: 1 trillion unique URL’s/links on the web at once! [http://www.emarketingtrends.co.za/2008/07/how-big-is-the-web/] • Google new Search Index Caffeine comprises • 100 Million Gigabytes i.e. 1017 Byte [http://googleblog.blogspot.com/2010/06/our-new-search-index-caffeine.html] • Deep web/ Dark web • estimated to be about 550 times bigger than Surface Web [http://en.wikipedia.org/wiki/Deep_Web] Quratulain Rajput

  6. Semantic data • Data has to enrich semantically, to retrieve relevant information. But • What is semantic? Quratulain Rajput

  7. Semantics • Semantics (from Greek: sēmantikós) is the study of meaning. It focuses on the relation between signifiers, like words, phrases, signs, and symbols. • The semantics of message depends on syntax, context and pragmatics and experience. Quratulain Rajput

  8. Syntax • Syntax (From ancient Greek, arrangement or ordering) is the study of the principles and processes by which sentences are constructed in particular languages. • Formal language syntax: The rules governing the behavior of mathematical systems (logic). • Computer programming language syntax:designed to communicate instructions to a computer. Quratulain Rajput

  9. Context • Context(language use) the relevant constraints of the communicative situation that influence language use. • Contexts denotes all elements of any sort of communication that define the interpretation of the communicated content, as e.g., • general contexts: place, time, interrelation of action in a message. • personal or social contexts: relation between sender and receiver of a message. Quratulain Rajput

  10. Pragmatics • Pragmatics is a subfield of linguistics which studies the ways in which context contributes to meaning. • The study of the speaker's meaning, not focusing on the phonetic or grammatical form of an expression, but instead on what the speaker's intentions and beliefs are. Quratulain Rajput

  11. EXPERIENCE • Experience as a general concept comprises knowledge of or skill of some thing or some event gained through involvement in or exposure to that thing or event Quratulain Rajput

  12. For successful communication, • • information has to be correctly transmitted (Syntax) • • the meaning (Semantics) of the transmitted information must be • interpreted correctly (= understanding) • • understanding depends on • • the context of both sender and receiver and • • the pragmatics of the sender • • the context of sender and receiver depends on • • the experience (knowledge of the world) of both sender and • receiver Dr. Harald Sack

  13. Lack of semantic Problem in Information retrieval • traditional keyword-based search leads to many not relevant results • different meanings • polysemy • Contexts missing Quratulain Rajput

  14. Lack of semantic Problem in Information Extraction Quratulain Rajput

  15. Lack of semantic Problem in Information Extraction • Information extraction can only be possible by a human. • Information is written in heterogeneous order. • Software agent cannot extract information due to lack of • knowledge of contexts • world knowledge and experience Quratulain Rajput

  16. Maintenance problem • Web site is a weakly connected structure of pages. • Inconsistency in links (semantically incorrect link or URL changed) • Maintenance is challenging problem to provide information with correctness and timeliness. Quratulain Rajput

  17. Lack of semantic problem in Personalization • Adapting user behavior of using/searching information. Lack of semantic problem: user Log file analysis cookies Quratulain Rajput

  18. Time for Quiz • Define the following terms. • Semantic • Syntax • Context • Pragmatic Quratulain Rajput

  19. The vision of the Semantic Web • The term semantic web proposed by Tim Berners Lee in the end of 1990’s. • The vision is that machine can participate on the behalf of user. • Existing search engines using Natural language processing techniques to extract meaning of information that is then utilize by machines. But limitation arises when meaning of information is not possible to extracted. Then the concept of Semantic Web comes in. • Semantic Web: explicitly annotated information with semantic metadata. so that information is read and interpreted correctly by machines. • For example Wikipedia content represent some explicit metadata, However not using semantic web technology. Quratulain Rajput

  20. Information representation • How to represent it semantically. Quratulain Rajput

  21. Dr. Harald Sack

  22. Dr. Harald Sack

  23. Well represented knowledge • The Meaning (Semantics) is expressed with the help of well suited knowledge representations (Ontologies) Person subClassOf subClassOf range domain Student Researcher hasSuperVisor type type Saad Sana hasSuperVisor Quratulain Rajput

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