19-07-2011, 12:21 PM
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1. ABSTRACT
In this presentation we discuss the concept of semantic web and ontologies. Ontology is an emerging concept, not only in the field of computer science but also medicine and other areas. We will first talk about what is semantic web, what is ontology? Then we will see an example of ontology and their design using an ontology building tool. Later we will discuss its advantages and how it helps in designing a database design and also how it helps in improving a database design. Ontology is a specification of a Conceptualization and is the basic structure around which we can build a knowledgebase. There are various tools available for developing ontologies and protégé is one of the most widely used ontology development editor which facilitates defining ontology concepts (classes), properties, taxonomies(or concept hierarchy), and various restrictions, as well as class instances and which supports several ontology representation languages, including OWL.
2. SEMANTIC WEB
2.1 Introduction
The Semantic Web is a mesh of information linked up in such a way as to be easily processable by machines, on a global scale. We can think of it as being an efficient way of representing data on the World Wide Web, or as a globally linked database. Semantic Web provides a common framework that allows data to be shared and reused across application, enterprise, and reused across community boundaries.
Semantic Web was invented by Tim Berner’s Lee, inventer of W3C.
According to Tim Berner’s Lee, “Semantic Web is an extension of the current web in which information is given well defined meaning, better enabling computers and people to work in cooperation.
It is the new-generation Web that tries to represent information such that it can be used by machines not just for display purposes, but for automation, integration, and reuse across applications [2].It allows the representation and exchange of information in a meaningful way [1].
The Semantic Web has been developing a layered architecture, was presented at XML2000 by Tim Berners-Lee, director of the World Wide Web Consortium (W3C) [1]:
Trust
Logic And Proof
Ontology
RDF Schema
RDF
XML Schema
XML
Unicode And URI
Fig 2.1.1: Semantic Web Layered Architecture
Unicode and URI: Unicode, the standard for computer character representation, and URIs, the standard for identifying and locating resources (such as pages on the Web), provide a baseline for representing characters used in most of the languages in the world, and for identifying resources.
XML: XML and its related standards, such as Namespaces, and Schemas, form a common means for structuring data on the Web but without communicating the meaning of the data. These are well established within the Web already.
Resource Description Framework: RDF is the first layer of the Semantic Web proper. RDF is a simple metadata representation framework, using URIs to identify Web-based resources and a graph model for describing relationships between resources. Several syntactic representations are available, including a standard XML format.
RDF Schema: a simple type modeling language for describing classes of resources and properties between them in the basic RDF model. It provides a simple reasoning framework for inferring types of resources.
Ontologies: a richer language for providing more complex constraints on the types of resources and their properties.
Logic and Proof: an (automatic) reasoning system provided on top of the ontology structure to make new inferences. Thus, using such a system, a software agent can make deductions as to whether a particular resource satisfies its requirements (and vice versa).
Trust: The final layer of the stack addresses issues of trust that the Semantic Web can support. This component has not progressed far beyond a vision of allowing people to ask questions of the trustworthiness of the information on the Web, in order to provide an assurance of its quality.
1. ABSTRACT
In this presentation we discuss the concept of semantic web and ontologies. Ontology is an emerging concept, not only in the field of computer science but also medicine and other areas. We will first talk about what is semantic web, what is ontology? Then we will see an example of ontology and their design using an ontology building tool. Later we will discuss its advantages and how it helps in designing a database design and also how it helps in improving a database design. Ontology is a specification of a Conceptualization and is the basic structure around which we can build a knowledgebase. There are various tools available for developing ontologies and protégé is one of the most widely used ontology development editor which facilitates defining ontology concepts (classes), properties, taxonomies(or concept hierarchy), and various restrictions, as well as class instances and which supports several ontology representation languages, including OWL.
2. SEMANTIC WEB
2.1 Introduction
The Semantic Web is a mesh of information linked up in such a way as to be easily processable by machines, on a global scale. We can think of it as being an efficient way of representing data on the World Wide Web, or as a globally linked database. Semantic Web provides a common framework that allows data to be shared and reused across application, enterprise, and reused across community boundaries.
Semantic Web was invented by Tim Berner’s Lee, inventer of W3C.
According to Tim Berner’s Lee, “Semantic Web is an extension of the current web in which information is given well defined meaning, better enabling computers and people to work in cooperation.
It is the new-generation Web that tries to represent information such that it can be used by machines not just for display purposes, but for automation, integration, and reuse across applications [2].It allows the representation and exchange of information in a meaningful way [1].
The Semantic Web has been developing a layered architecture, was presented at XML2000 by Tim Berners-Lee, director of the World Wide Web Consortium (W3C) [1]:
Trust
Logic And Proof
Ontology
RDF Schema
RDF
XML Schema
XML
Unicode And URI
Fig 2.1.1: Semantic Web Layered Architecture
Unicode and URI: Unicode, the standard for computer character representation, and URIs, the standard for identifying and locating resources (such as pages on the Web), provide a baseline for representing characters used in most of the languages in the world, and for identifying resources.
XML: XML and its related standards, such as Namespaces, and Schemas, form a common means for structuring data on the Web but without communicating the meaning of the data. These are well established within the Web already.
Resource Description Framework: RDF is the first layer of the Semantic Web proper. RDF is a simple metadata representation framework, using URIs to identify Web-based resources and a graph model for describing relationships between resources. Several syntactic representations are available, including a standard XML format.
RDF Schema: a simple type modeling language for describing classes of resources and properties between them in the basic RDF model. It provides a simple reasoning framework for inferring types of resources.
Ontologies: a richer language for providing more complex constraints on the types of resources and their properties.
Logic and Proof: an (automatic) reasoning system provided on top of the ontology structure to make new inferences. Thus, using such a system, a software agent can make deductions as to whether a particular resource satisfies its requirements (and vice versa).
Trust: The final layer of the stack addresses issues of trust that the Semantic Web can support. This component has not progressed far beyond a vision of allowing people to ask questions of the trustworthiness of the information on the Web, in order to provide an assurance of its quality.