1. Dr. Bhavani Thuraisingham August 2006 Building Trustworthy Semantic Webs Unit #1: Introduction to The Semantic Web

2. 12-2 6/2/2016 18:11 Objective of the Unit 0 This unit will provide an overview of the semantic web and discuss the information management technologies for the semantic web 0 Reference: XML, Databases and the Semantic Web, CRC Press, Thuraisingham, March 2002

3. 12-3 6/2/2016 18:11 Outline of the Unit 0 Semantic Web Overview 0 Web Data Management and Web Services 0 XML (eXtensible Markup Language) 0 RDF (Resource Description Framework) 0 Information Integration and Ontologies 0 Rules Processing 0 Coalition Testbed Suggestion 0 Directions

4. 12-4 6/2/2016 18:11 Semantic Web: Overview 0 According 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 database Premise: Semantic Web Technologies = XML, RDF, Ontologies, Rules Applications: Web Database Management, Web Services, Information Integration

5. 12-5 6/2/2016 18:11 Layered Architecture for Dependable Semantic Web 0 Some Challenges: Interoperability between Layers; Security and Privacy cut across all layers; Integration of Services; Composability XML, XML Schemas Rules/Query Logic, Proof and Trust TRUSTTRUST Other Services RDF, Ontologies URI, UNICODE PRIVACYPRIVACY 0 Adapted from Tim Berners Lee’s description of the Semantic Web

6. 12-6 6/2/2016 18:11 Relationships between Dependability, Confidentiality, Privacy, Trust Dependability Confidentiality Privacy Trust Dependability: Security, Privacy, Trust, Real-time Processing, Fault Tolerance; also sometimes referred to as “Trustworthiness” Confidentiality: Preventing the release of unauthorized information considered sensitive Privacy: Preventing the release of unauthorized information about individuals considered sensitive Trust: Confidence one has that an individual will give him/her correct information or an individual will protect sensitive information

7. 12-7 6/2/2016 18:11 What is XML all about? 0 XML is needed due to the limitations of HTML and complexities of SGML 0 It is an extensible markup language specified by the W3C (World Wide Web Consortium) 0 Designed to make the interchange of structured documents over the Internet easier 0 Key to XML is Document Type Definitions (DTDs) -Defines the role of each element of text in a formal model 0 Allows users to bring multiple files together to form compound documents

8. 12-8 6/2/2016 18:11 Example XML Document Patents Funds Year: 2002 Name: U. Of X Expenses Name: CS titleAuthor ID Asset report Assets Dept Equipment news Patent Other assets Grants Contracts

9. 12-9 6/2/2016 18:11 Specifying User Credentials in XML Alice Brown University of X CS Security John James University of X CS Senior

10. 12-10 6/2/2016 18:11 Specifying Security Policies in XML <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 = - - - - 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 department

11. 12-11 6/2/2016 18:11 RDF 0 Resource Description Framework is the essence of the semantic web 0 Adds semantics with the use of ontologies, XML syntax 0 RDF Concepts - Basic Model =Resources, Properties and Statements -Container Model =Bag, Sequence and Alternative

12. 12-12 6/2/2016 18:11 Ontology Mappings 0 Common definitions for any entity, person or thing 0 Several ontologies have been defined and available for use 0 Defining common ontology for an entity is a challenge 0 Mappings have to be developed for multiple ontologies 0 Specific languages have been developed for ontologies including RDF and OIL (Ontology Interface Language)

13. 12-13 6/2/2016 18:11 Rules Processing User Interface Manager Constraint Manager Rules/ Constraints Query Processor: Constraints during query and release operations Update Processor: Constraints during update operation XML Database Design Tool Constraints during database design operation XML Database XML Document Manager

14. 12-14 6/2/2016 18:11 Rule-Processing (Concluded) Policies Ontologies Rules Semantic Web Engine XML, RDF Documents Web Pages, Databases Inference Engine/ Rules Processor Interface to the Semantic Web Technology By W3C

15. 12-15 6/2/2016 18:11 Semantic Web Database Management 0 Database access through the semantic web -XML, RDF technologies 0 Query, indexing and transaction management for web databases -E.g., New kinds of transaction models for E-commerce applications -Index strategies for unstructured data 0 Query languages and data models -XML has become the standard document interchange language 0 Managing XML/RDF databases on the web -XML-QL, Extensions to XML, Query and Indexing strategies

16. 12-16 6/2/2016 18:11 Web Services 0 Web Services are about services on the web for carrying out many functions including directory management, source location, subscribe and publish, etc. 0 Web services description language (WSDL) exists for web services specification 0 Web services architectures have been developed 0 Challenge now is to compose web services; how do you integrate multiple web services and provide composed web service in a seamless fashion 0 Ultimate goal is to have web services for information integration

17. 12-17 6/2/2016 18:11 Web service architecture Service requestor Service providers UDDI Publish Query Answer Request the service

18. 12-18 6/2/2016 18:11 Secure Web Service Architecture Confidentiality, Authenticity, Integrity Service requestor Service provider UDDI Query BusinessEntity BusinessService BindingTemplate BusinessService tModel PublisherAssertion

19. 12-19 6/2/2016 18:11 Example Web Service 0 Publish/Subscribe Service

20. 12-20 6/2/2016 18:11 Information Integration 0 Data Integration: -Integrate the data from the heterogeneous databases and data sources =Challenges: Common data model, Mappings between data models, Schema integration, Semantic heterogeneity, Handling heterogeneous query models, transaction strategies, security policies, etc. 0 Information Integration -Integrate heterogeneous information sources 0 Knowledge integration -Integrate heterogeneous knowledge sources

21. 12-21 6/2/2016 18:11 Coalition Application Testbed: A Suggestion 0 Identify Coalition -Identify Coalition Example: A good starting point will be the Coalition experiments conduced under DARPA;s CoABS program that includes MBP (Master Battle Planner) and CAMPS (Consolidated Air Mobility Planning System) applications -Develop scenarios and determine the roles are of the coalition partners -Identify information to be accessed/shared and how the semantic web may be used by the coalition 0 Design Policies -Design policies (e.g., security, privacy, trust) for the coalition when accessing information resources 0 Implement Test Bed -Develop a test bed that uses ontologies for information integration and enforces the policies

22. 12-22 6/2/2016 18:11 Vision for Dependable Semantic Web Core Semantic Web Technologies: Systems, Networks, Agents, AI, Machine Learning, Data Mining, Languages, Software Engineering, Information Integration Need research to bring together the above technologies Directions: Security/Trust/Privacy, Integrate sensor technologies, Pervasive computing, Social impact Domain specific semantic webs: DoD, Intelligence, Medical, Treasury,- - - 0 Some Challenges: Secure Semantic Interoperability; Secure Information Integration; Integrating Pervasive computing and sensors