Slide 1Objective of the UnitOutline of the UnitSemantic Web: OverviewLayered Architecture for Dependable Semantic WebRelationships between Dependability, Confidentiality, Privacy, TrustWhat is XML all about?Example XML DocumentSpecifying User Credentials in XMLSpecifying Security Policies in XMLRDFOntology MappingsRules ProcessingRule-Processing (Concluded)Semantic Web Database ManagementWeb ServicesWeb service architectureSecure Web Service ArchitectureExample Web ServiceInformation IntegrationCoalition Application Testbed: A SuggestionVision for Dependable Semantic WebDr. Bhavani ThuraisinghamAugust 2006Building Trustworthy Semantic WebsUnit #1: Introduction to The Semantic Web12-201/14/19 06:05 Objective of the Unit0This unit will provide an overview of the semantic web and discuss the information management technologies for the semantic web0Reference: XML, Databases and the Semantic Web, CRC Press, Thuraisingham, March 200212-301/14/19 06:05 Outline of the Unit0Semantic Web Overview0Web Data Management and Web Services0XML (eXtensible Markup Language)0RDF (Resource Description Framework)0Information Integration and Ontologies0Rules Processing0Coalition Testbed Suggestion0Directions12-401/14/19 06:05 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 Integration12-501/14/19 06:05 Layered Architecture for Dependable Semantic Web0 Some Challenges: Interoperability between Layers; Security and Privacy cut across all layers; Integration of Services; ComposabilityXML, XML SchemasRules/QueryLogic, Proof and TrustTRUSTOtherServicesRDF, OntologiesURI, UNICODEPRIVACY0Adapted from Tim Berners Lee’s description of the Semantic Web12-601/14/19 06:05 Relationships between Dependability, Confidentiality, Privacy, TrustDependabilityConfidentialityPrivacyTrustDependability: Security, Privacy, Trust, Real-time Processing, Fault Tolerance; also sometimes referred to as “Trustworthiness”Confidentiality: Preventing the release of unauthorized information considered sensitivePrivacy: Preventing the release of unauthorized information about individuals considered sensitiveTrust: Confidence one has that an individual will give him/her correct information or an individual will protect sensitive information12-701/14/19 06:05 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 is Document Type Definitions (DTDs)-Defines the role of each element of text in a formal model0Allows users to bring multiple files together to form compound documents12-801/14/19 06:05 Example XML DocumentPatentsFundsYear: 2002Name: U. Of XExpensesName:CStitleAuthorIDAsset reportAssetsDeptEquipmentnewsPatentOther assetsGrantsContracts12-901/14/19 06:05 Specifying User Credentials in XML<Professor credID=“9” subID = “16: CIssuer = “2”><name> Alice Brown </name><university> University of X <university/><department> CS </department><research-group> Security </research-group></Professor><Secretary credID=“12” subID = “4: CIssuer = “2”><name> John James </name><university> University of X <university/><department> CS </department><level> Senior </level></Secretary>12-1001/14/19 06:05 Specifying Security Policies in XML<? Xml VERSION = “1.0” ENCODING = “utf-8”?> <Policy–base> <policy-spec cred-expr = “//Professor[department = ‘CS’]” target = “annual_ report.xml” path = “//Patent[@Dept = ‘CS’]//Node()” priv = “VIEW”/> <policy-spec cred-expr = “//Professor[department = ‘CS’]” target = “annual_ report.xml” path = “//Patent[@Dept = ‘EE’] /Short-descr/Node() and //Patent [@Dept = ‘EE’]/authors” priv = “VIEW”/> <policy-spec cred-expr = - - - - <policy-spec cred-expr = - - --</Policy-base>Explantaion: CS professors are entitled to access all the patents of their department. They are entitled to see only the short descriptions and authors of patents of the EE department12-1101/14/19 06:05 RDF0Resource Description Framework is the essence of the semantic web0Adds semantics with the use of ontologies, XML syntax0RDF Concepts- Basic Model =Resources, Properties and Statements-Container Model=Bag, Sequence and Alternative12-1201/14/19 06:05 Ontology Mappings0Common definitions for any entity, person or thing0Several ontologies have been defined and available for use0Defining common ontology for an entity is a challenge0Mappings have to be developed for multiple ontologies0Specific languages have been developed for ontologies including RDF and OIL (Ontology Interface Language)12-1301/14/19 06:05 Rules ProcessingUser Interface ManagerConstraintManagerRules/ ConstraintsQuery Processor:Constraints during query and release operationsUpdate Processor:Constraints during update operationXML Database Design ToolConstraints during database design operationXMLDatabaseXML DocumentManager12-1401/14/19 06:05 Rule-Processing (Concluded)PoliciesOntologies RulesSemantic Web EngineXML, RDF DocumentsWeb Pages, DatabasesInference Engine/Rules ProcessorInterface to the Semantic WebTechnologyBy W3C12-1501/14/19 06:05 Semantic Web Database Management0Database access through the semantic web-XML, RDF technologies0Query, indexing and transaction management for web databases-E.g., New kinds of transaction models for E-commerce applications-Index strategies for unstructured data0Query languages and data models-XML has become the standard document interchange language0Managing XML/RDF databases on the web-XML-QL, Extensions to XML, Query and Indexing strategies12-1601/14/19 06:05 Web Services0Web Services are about services on the web for carrying out many functions including directory management, source location, subscribe and publish, etc.0Web services description language (WSDL) exists for web services specification0Web services architectures have been developed0Challenge now is to compose web services; how do you integrate multiple web services and provide composed web service in a
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