Slide 1Outline of Part 1Semantic Web: OverviewToday’s Web to Semantic webKnowledge Management and Personal AgentsE-commerceSome aspects of semantic webLayered Approach: Tim Berners Lee’s Vision www.w3c.orgSemantic Web and Its ApplicationsLayered Architecture for Dependable Semantic Web at UTDWhat is XML all about?Example XML DocumentRDFOntologyOWL: BackgroundWhy Rules?What is Ontology Engineering?VisionOutline of Part IISemantic Social NetworksFOAFFOAF ExampleSlide 23Slide 24FLINK (Peter Mika, Free University)FLINK ArchitectureSlide 27Social Network Analysis on Semantic Web DataGroup DetectionLinking Social Networks with FOAFExtracting Social NetworksExtracting Social Networks (Tim Finin)ConvergenceSlide 34Slide 35Dr. Bhavani ThuraisinghamJune 2010Knowledge Management, Semantic Web and Social NetworkingIntroduction to the Semantic Web13-201/14/19 14:56 Outline of Part 10Today’s web to tomorrow’s web0Semantic web0XML, RDF, Ontologies, OWL Rules0Ontology Engineering0Vision13-301/14/19 14:56 Semantic Web: Overview0According to Tim Berners Lee, The Semantic Web supports-Machine readable and understandable web pages-Enterprise application integration-Nodes and links that essentially form a very large databasePremise:Semantic Web Technologies = XML, RDF, Ontologies, RulesApplications: Web Database Management, Web Services, Information Integration13-401/14/19 14:56 Today’s Web to Semantic web0Today’s web-High recall, low precision: Too many web pages resulting in searches, many not relevant; Sometimes low recall-Results sensitive to vocabulary: Different words even if they mean the same thing do not results in same web pages; Results are single web pages not linked web pages0Semantic web-Machine understandable web pages-Activities on the web such as searching with little or no human intervention-Solutions to the problems faced by today’s web-Retrieving appropriate web pages, sensitive to vocabulary13-501/14/19 14:56 Knowledge Management and Personal Agents0Knowledge Management-Corporation Need: Searching, extracting and maintaining information, uncovering hidden dependencies, viewing information-Semantic web for knowledge management=Organizing knowledge, automated tools for maintaining knowledge, question answering, querying multiple documents, controlling access to documents0Agents-John is a president of a company. He needs to have a surgery. With current web he has to check each web page for relevant information, make decisions depending on the information provided-With the semantic web, the agent will retrieve all the relevant information, synthesize the information, ask John if needed, and then present the various options to John and also makes recommendations13-601/14/19 14:56 E-commerce0Business to Consumer-Users shopping on the web; wrapper technology is used to extract information about user preferences etc. and display the products -Use of semantic web: Develop software agents that can interpret privacy requirements, pricing and product information and display timely and correct information to the use; also provides information about the reputation of shops-Future: negotiation among the behalf of the user0Business to Business-Organizations work together and carrying out transactions such as collaborating on a product, supply chains etc. With today’s web lack of standards for data exchange-Use of semantic web: XML is a big improvement, but need to agree on vocabulary. Future will be the use of ontologies to agree on meanings and interpretations13-701/14/19 14:56 Some aspects of semantic web0Explicit Metadata-Metadata is data about data; Need metadata to be explicitly specified so that different groups and organizations will know what is on the web-Using metadata, one can then carry out various activities such as searching, integration and executing actions-Metadata specification languages include XML, RDF, OWL0Semantic web vs Artificial Intelligence-Goal of Artificial Intelligence is to build an intelligent agent exhibiting human-level intelligence; Goal of the semantic web is to assist the humans in their day to day online activities0Logic and Reasoning-Logic can be used to specify facts as well as rules; New facts and derived from existing facts based on the inference rules; Descriptive Logic is the type of logic that has been developed for semantic web applications13-801/14/19 14:56 Layered Approach: Tim Berners Lee’s Visionwww.w3c.org13-901/14/19 14:56 Semantic Web and Its ApplicationsXML, XML SchemasRules/QueryLogic, Proof and TrustRDF, OntologiesURI, UNICODEApplicationsTim Berners Lee’s TechnologyStackWeb ServicesInformationIntegrationInformationSharing13-1001/14/19 14:56 Layered Architecture for Dependable Semantic Web at UTD0 Some Challenges: Security and Privacy cut across all layers; Integration of Services; ComposabilityXML, XML SchemasRules/QueryLogic, Proof and TrustSECURITYOtherServicesRDF, OntologiesURI, UNICODEPRIVACY0Adapted from Tim Berners Lee’s description of the Semantic Web13-1101/14/19 14:56 What is XML all about?0XML is needed due to the limitations of HTML and complexities of SGML0It is an extensible markup language specified by the W3C (World Wide Web Consortium)0Designed to make the interchange of structured documents over the Internet easier0Key to XML used to be Document Type Definitions (DTDs)-Defines the role of each element of text in a formal model0XML schemas have now become critical to specify the structure-XML schemas are also XML documents13-1201/14/19 14:56 Example XML DocumentPatentsFundsYear: 2002Name: U. Of XExpensesName:CStitleAuthorIDAsset reportAssetsDeptEquipmentnewsPatentOther assetsGrantsContracts13-1301/14/19 14:56 RDF0Resource Description Framework is the essence of the semantic web0XML cannot be used to specify semantics0Example:-Professor is a subclass of Academic Staff-Professor inherits all properties of Academic Staff0RDF was specified so that the inadequacies of XML could be handled; RDF uses XML Syntax0RDF Concepts- Basic Model =Resources, Properties and Statements-Container Model=Bag, Sequence and Alternative13-1401/14/19 14:56 Ontology0RDF has issues also-Cannot express several other properties such as Union, Interaction, relationships, etc0Need a richer language; Ontology languages were developed by the semantic web community for this purpose0What are ontologies?-Common definitions for any entity, person or thing-Several
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