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Introduction to the Semantic Web - Vision and Technologies
 

Introduction to the Semantic Web - Vision and Technologies

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Understand and articulate the semantic web vision. Know the basic framework and core technologies. Be aware of some available tools. Understand how mature the technology is and how you might (or might ...

Understand and articulate the semantic web vision. Know the basic framework and core technologies. Be aware of some available tools. Understand how mature the technology is and how you might (or might not) use it today. Get involved for further learning, contribution, or just plain geek fun.

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  • Protégé is a free , open source ontology editor and knowledge-base framework. Developed by Stanford Medical Informatics with support from DARPA and others A cool tool – even if you could care less about the semantic web A bit of a learning curve, but great fun! You may never use a relational database for personal stuff again Screenshots follow…
  • Classes view shows a class tree of the classes in your ontology. Properties tab shows a list of property objects in your ontology. Navigator shows a list of ontologies used in each project; user can switch between them.
  • Lay-out is automatic, but a user can adjust the diagram by moving each class. Black arrows are subclass relationship Blue arrows show other relationships between classes, e.g., restrictions
  • Haystack Semantic Web Browser - A “Semantic Desktop” Concept Eclipse based Information in One Place Right Click on Anything Work with Information, Not Programs Drag and Drop E-mail and Instant Messaging Together Personal Digital Library And more…
  • Search Today’s search engines are based primarily on word occurrence They do not reason on data nor infer meaning Search is augmented with advertisements, not meaningful data relationships “ Yo-Yo Ma” might get augmented with his current concert schedule, his music albums, his image, etc. Combining data (personal, company, web) from disparate sources with reduced or no API programming. Software cannot easily leverage search automatically as a background process Desktop Application Integration Too many apps and too much propriety to expect well-orchestrated standards. Need “serendipitous interoperability”. Ubiquitous Computing The key issue (and goal) of ubiquitous computing is "serendipitous interoperability," interoperability under "unchoreographed" conditions, i.e., devices which weren't necessarily designed to work together (such as ones built for different purposes, by different manufacturers, at a different time, etc.) should be able to discover each others' functionality and be able to take advantage of it. Being able to "understand" other devices, and reason about their services/functionality is necessary, since full-blown ubiquitous computing scenarios will involve dozens if not hundreds of devices, and a priori standardizing the usage scenarios is an unmanageable task.

Introduction to the Semantic Web - Vision and Technologies Introduction to the Semantic Web - Vision and Technologies Presentation Transcript

  • Introduction to the Semantic Web Vision and Technologies Cody Burleson EMT-070
  • Software and Information Architects
    • Session Objectives
    • After completing this session,
    • you should be able to:
      • Understand and articulate the semantic web vision
      • Know the basic framework and core technologies
      • Be aware of some available tools
      • Understand how mature the technology is and how you might (or might not) use it today
      • Get involved for further learning, contribution, or just plain geek fun
  • The semantic web is…
    • A vision for the future web (a ‘web of meaning’ - semantics )
      • Not a separate web but an extension of the current one
      • Better enabling computers and people to work in cooperation
      • Machine reasoning will be ubiquitous and powerful
    • An emerging set of standards, markup languages, and related processing tools
    • A rolling snowball
      • Interest and momentum is building fast - heads up!
    Currently under the direction of Tim Berners-Lee (a.k.a. “father of the Web”) http://www.w3.org/2001/sw/ The Semantic Web Activity
  • “Semantics” is…
    • A $2 billion per year market and projected to grow to over $50 billion by the year 2010 . Leading analysts have estimated that 35-65% of our System Integration costs are due to Semantic issues. – source: SemTech 2006 , http://www.semantic-conference.com/
    Business Componentization + Service Oriented Architecture -> Increased Integration Requirements Time Integration Requirements (people, data, process) 2015 2010 2005 2004 O(n) components => O(n 2 ) integrations IT Project Resources (Budgets, Time) Market Opportunity for better Integration Solutions
  • The semantic web stack Unicode URI XML + NS + xmlschema RDF + rdfschema Ontology vocabulary Logic Proof Trust Digital Signature Self-desc. doc Data Data Rules
  • Resource Description Framework (RDF)
    • The Resource Description Framework (RDF) is a standard for describing resources ( anything we can identify ).
    • Describes resources in terms of nodes and arcs
    http://...//CodyBurleson Cody Burleson vcard:FN SUBJECT A resource (node in URI) PREDICATE Has a property that points (arcs) to… OBJECT A literal value or another resource
  • Resource Description Framework (RDF) Source: Semantic Search http://www2003.org/cdrom/papers/refereed/p779/ess.html
  • Resource Description Framework (RDF)
    • This article has the title “Intro to the Semantic Web Vision and Technologies", and was written by someone whose name is “Cody Burleson".
    • It leverages and combines two vocabularies…
    <rdf:RDF xmlns:rdf=&quot;http://www.w3.org/1999/02/22-rdf-syntax-ns#&quot; xmlns:dc=http://purl.org/dc/elements/1.1/ xmlns:foaf=&quot;http://xmlns.com/0.1/foaf/&quot; > <rdf:Description rdf:about=&quot;&quot;> <dc:creator rdf:parseType=&quot;Resource&quot;> <foaf:name>Cody Burleson</foaf:name> </dc:creator> <dc:title>Intro to the Semantic Web Vision and Technologies</dc:title> </rdf:Description> </rdf:RDF> Dublin Core Metadata Initiative (DC) http://dublincore.org/ Friend of a Friend (foaf) http://www.foaf-project.org/
  • Notable points
    • Distributed Extensibility
      • Different sites may contribute data about a particular resource
      • We can all extend the cumulative knowledge on the Semantic Web about any resource in a distributed fashion
    • A version of RSS , the famous syndication (content feeds) format is a sub-set of RDF
    • IBM case-in-point:
      • The new RSS Consumer being developed for WebSphere Web Content Management (WCM) leverages the extensibility of RDF to add special elements into the standard RSS.
      • This allows for integration with other Content Management Systems like Interwoven and Vignette.
  • Ontology
    • A formal way to organize knowledge and terms. 
    • Typically represented as graphical relationships or networks, as opposed to taxonomies which are usually represented hierarchically. 
    • Defines a domain of knowledge
      • The objects that exist in that domain
      • The properties those objects can have
      • The relationships those objects and their properties can have to other objects and properties (in the same domain or across domains)
    • What are the differences between a vocabulary, a taxonomy, a thesaurus, an ontology, and a meta-model?
      • See: http://www.metamodel.com/article.php?story=20030115211223271
    “ An ontology is an explicit specification of a conceptualization.” - T. R. Gruber (…whatever…)
  • This is an ontology Source: TopQuadrant
  • OWL Web Ontology Language
    • Designed for use by applications that need to process the content of information instead of just presenting information to humans.
    • Has three increasingly-expressive sublanguages: OWL Lite, OWL DL, and OWL Full.
    • OWL adds more vocabulary for describing properties and classes on top of RDF. Example:
      • Disjointness
        • Man and Woman are Disjoint Classes. Joan is an instance of Woman => Joan is not an instance of Man.
      • Cardinality
        • Person has exactly one value for the property hasBirthMother
      • Equality
        • Bill Clinton is sameAs William Jefferson Clinton
      • Symmetry
        • Frank is a friend of Deborah => Deborah is a friend of Frank.
    Yep…the acronym should be ‘WOL’, but the creators thought ‘OWL’ was much cooler.
  • Tools
  • Jena
    • An open source Semantic Web Framework for Java
    • Developed by HP Labs Semantic Web Program
    • Provides a programmatic environment for RDF, RDFS and OWL, including a rule-based inference engine
    • Includes:
      • A RDF API
      • Reading and writing RDF in RDF/XML, N3 and N-Triples
      • An OWL ontology API
      • In-memory and persistent storage (works with DB2)
      • RDQL – a query language for RDF
    A Semantic Web Framework for Java http://jena.sourceforge.net/
  • Protégé Screenshot 2 – Protégé-OWL Ontology Editing and Knowledge Management http://protege.stanford.edu/
  • TopQuadrant’s TopBraid: An Eclipse Tool Source: TopQuadrant
  • TopBraid: UML-like Visualization Source: TopQuadrant
  • Haystack - Screenshot Haystack A semantic web browser http://haystack.csail.mit.edu/overview.html
  • Other Tools and Technologies
    • IBM Integrated Ontology Development Toolkit
      • http://www.alphaworks.ibm.com/tech/semanticstk?open&S_TACT=104AHW61&S_CMP=GR
      • Based on Eclipse EMF
      • Implements the ODM specification(OMG)
    • SPARQL - The W3C RDF Data Access Working Group (DAWG)
      • http://www.w3.org/2001/sw/DataAccess/
      • RDF Query Language and protocol (for issuing SPARQL queries)
      • SPARQL is already implemented in many RDF stores (including ARQ, the query component of Jena)
      • IBM reps to the DAWG
        • Lee Feigenbaum
        • Elias Torres
    • Rule Interchange Format
      • http://www.w3.org/2005/rules/Overview.html
      • IBM reps
        • Leora Morgenstern
        • Christopher Welty (co-chair)
  • How mature is the technology and how might you use it?
  • A simple test case
    • Can we build some sort of semantic web application using RDF/OWL for our data model?
    • Technologies used:
      • Protégé for ontology development
      • Protégé and Protégé-OWL API for engine
      • JavaServer Faces
      • WebSphere Application Server
      • Rational Software Architect
    Test Case Ontology… (…after conversion to Java Objects)
  • Test Case Screen 1
  • Test Case Screen 2
  • Test Case Screen 3
  • Test Case Screen 4 Resource information (the data) shows in left pane. All related resources attached for multi-faceted browsing
  • Some Lessons Learned
    • No “right” way to model an ontology.
      • Depends upon the end-use cases you have in mind
      • Depends on whether you intend to reason (engine) and auto-classify
      • Depends on personal preferences
      • 1-2 weeks of playing with Protégé and learning about OWL
      • Rebuilt ontology up to 3 times before starting to code
    • Wanted a dynamic model so that you can change ontology only without recoding application
      • Ended up generating Java objects from ontology using Protégé OWL’s Java code generation feature (lazy, I guess)
      • Totally dynamic model is still doable (perhaps I should have used Jena OWL API?) Need more time.
    • Ontology + auto generate Java model + Java Server Faces + Rational = Drag and drop development and very little code!
    • Discovered IBM Research projects after-the-fact
      • Wish I would have used our stuff; some of it is very cool
    • Total time = 2 months learning and experimenting (off-time)
      • Now “I get it”…and want to start over.
  • Ready for prime time?
    • Data modeling
      • YES
      • Ontology-based approach to data modeling is highly beneficial
    • Horizontal integration (breaking down &quot;silos&quot;)
      • YES, sort of…
      • The tools are there, but they aren’t baked in to many enterprise products
      • Concepts may be “too new” for customer comfort
      • Opportunity for IBM to take a stronger leadership role.
    • Machine-driven interpretation (i.e. inference, rules engines, etc.)
      • NO
      • Not mature, slow, or based on rapidly evolving standards
      • A big pill to swallow at first; learn the basics before getting into inference, rules, and reasoning.
    • CONCLUSION:
      • “ Semantic Web” as a concept may not be ready for prime time, but it is ready for our attention
      • Many semantic web technologies are mature and immediately beneficial
      • Learning curve is rather steep (or I’m slow) – get started!
  • Get involved, learn, contribute, and have some fun…
  • @ IBM
    • Semantics on AlphaWorks
      • http://www.alphaworks.ibm.com/topics/semantics
      • Flash Demos: http://www.alphaworks.ibm.com/demo/flash/wssem
    • Semantic Tools for Web Services
      • http://w3.alphaworks.ibm.com/techs/alphabrief.jsp?tech=wssem
      • A set of Eclipse plug-ins for semantic matching and composition of Web services. (This is an ETTK technology.)
    • Semantic Layer Research Platform
      • On IBM Internal Open Source Bazaar
      • http://w3.opensource.ibm.com/projects/slrp/
      • A platform for building Semantic applications that use RDF, LSID and other Semantic Web technologies. The platform includes several components such as an RDF server with collections, acls, replication and transactions, client and web development kits including an Eclipse suite of plugins for RDF consumption. This project also contains several prototypes such as Life Sciences Workbench and Unified Activity Management.
    • Semantic Super Computing
      • On IBM Internal Open Source Bazaar
      • http://w3.opensource.ibm.com/projects/ssc/
      • The Semantic Super Computing project performs research on large amount of data or large amount of computation. The aim is to explore innovative way to deal with the scalability issues and user interface problems of such projects.
    • Watson Research Semantics Wiki
      • http://semanticswiki.watson.ibm.com/FrontPage
    • Blue Pages
      • Search entire profile for “Semantic Web”
      • 39 results as of 1/31/2006
  • Others…
    • HP Labs Semantic Web Research
      • http://www.hpl.hp.com/semweb/
      • Research group aiming to enable semantic web benefits for HP customers and partners.
      • Provides most popular semantic web API:
        • Jena 2 - a Java framework for writing Semantic Web applications
    • TopQuadrant
      • http://www.topquadrant.com/
      • Established in 2001 as a premier semantic web solutions firm.
  • More…
    • Sandsoft - “The Ontology Company”
      • http://www.sandsoft.com/
      • An IBM partner
    • Semantical.org – “Promote and advancing the state of the art in the establishment of the commercial Semantic Web”
      • http://semantical.org/
      • Recent launch: open source semantic web-based search engine
    • Nepomuk – “$20 million EU-backed project that aims to create a next-generation computing approach known as the ‘Social Semantic Desktop’.
      • http://nepomuk.semanticdesktop.org/xwiki/bin/Main1/
  • A few reference resources
    • Google “Semantic Web” – you’ll be reading for hours.
    • The Semantic Web. Scientific American May 2001. http://www.sciam.com/article.cfm?articleID=00048144-10D2-1C70-84A9809EC588EF21
    • SWAD-Europe
      • http://www.w3.org/2001/sw/Europe/
      • The SWAD-Europe project ran from May 2002 to October 2004, and aimed to support W3C's Semantic Web initiative in Europe, providing targeted research, demonstrations and outreach to ensure Semantic Web technologies move into the mainstream of networked computing.
    • Semantic Web Best Practices Discussion List
      • http://lists.w3.org/Archives/Public/public-swbp-wg/
    • Ontologies Come of Age. By Deborah L. McGuinness. In “The Semantic Web: Why, What and How” MIT Press
    • Semantic Web Technologies Take Middleware to Next Level – Gartner Report 20 August 2002
    • The Semantic Web: Trying to Link the World – Gartner Report 30 August 2001
    • The Integrated Enterprise From 2003 to 2012 - Gartner Report dated 12/3/02 by J. Fenn, Y. Natis, J. Sinur, A. Linden
    • Integration’s Dirty Little Secret: It’s a matter of Semantics- by Jeff Pollack Modulant Software http://www.modulant.com/PDFs/dirty_little_secret.pdf
    • Semantic Information Architecture: Solving the Enterprise Data Problem. Executive White paper by Zvi Schreiber. Unicorn 2003. http://www.dmreview.com/whitepaper/WID532.pdf
  • Session Summary
    • Now that you have completed this session, you should be able to:
      • Understand and articulate the semantic web vision
      • Know the basic framework and core technologies
      • Be aware of some of available tools
      • Understand how mature the technology is and how you might (or might not) use it today
      • Get involved for further learning, contribution, or just plain geek fun
  • Extra Slides
    • Misc. stuff.
  • Imagine…
    • A web that computers (not just humans) can understand.
    • Intelligent search, augmented search, automated search
    • Better enterprise application integration
      • Integration at the data layer rather than the API layer – reduced programming
      • Universal data exchange
      • Automatic and ad hoc configuration
      • Better service discovery
      • “ Serendipitous interoperability” (interoperability under unchoreographed conditions)
      • Semantics can bring us closer to the vision of SOA
        • Example: WebSphere Process Server looks up best service based on the semantic descriptions rather than calling service directly.
      • Semantics can give us better On Demand Workplaces
        • Better ways to integrate the “thousand tribes” intranet into one comprehensive, yet personalized web portal
    • Improved Systems and Software Engineering
      • Model Driven Architectures (using ontology approach to models)
      • One example: http://www.w3.org/2001/sw/BestPractices/SE/ODA/
      • See also:
        • Ontology-based Web Services for Business Integration
        • http://www.alphaworks.ibm.com/tech/owsbi
    • Comprehensive desktop application integration
    • An army of intelligent agents working on your behalf
  • Technology Trends
    • Semantic Modeling Languages gaining Standards’ Acceptance
    Time Integration/Modeling Language Adoption Cycle HTML RDF OWL XML 2003 1997 1996 1991 Foundations for Semantics 1994 Semantics Syntax Presentation DTDs XML Schema RDF Schema 1999
  • Trends
    • Web standards: from presentation to semantics
    Modeling Language Degree of Semantic Specification RDF Schema XML Schema DTDs HTML XML Semantics Syntax Presentation RDF OWL
  • Trends
    • Semantics enable next generation integration solutions
    “ By 2005, lightweight ontologies will be part of 75% of application integration projects (0.7 probability) ” – Gartner Report August 2002 “ Through 2012, Semantic Web technologies will offer the infrastructure for the much-improved, unified semantics that are needed to support dynamic application integration at the enterprise level ”. - Gartner Report Dec 2002 Time Semantic Technologies 2015 2010 2005 2004 Ontologies for Data & Content Management Semantic Web Services for Dynamic Application Integration