tu/e technische universiteit eindhoven assignment 1 if e-mail failed try: –electronically: bscw...
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TU/e technische universiteit eindhoven
Assignment 1
• If e-mail failed try:– Electronically: BSCW– Physically: MailBox outside HG7.75– More info:
http://wwwis.win.tue.nl/~houben/wis/
• Deadline extended to today until 23:59
TU/e technische universiteit eindhoven
Semantic Web Applications
Kees van der Sluijs
TU/e technische universiteit eindhoven
Contents
• Introduction
• Utilization of the Semantic Web
• Selection of Developer Tools
• Selection of End-User Applications
• Examples of Techniques
TU/e technische universiteit eindhoven
Introduction
TU/e technische universiteit eindhoven
Why Semantic Web?
• You have seen some Whats and Hows– But what can you do with it?
TU/e technische universiteit eindhoven
Proposed Benefits
• Information Standardization
• Flexibility
• Semantic Interoperability
• More Collaboration
• Backward and Forward compatibility
• Greater (re-)use of off-the-shelf software
TU/e technische universiteit eindhoven
Utilization of the Semantic Web
TU/e technische universiteit eindhoven
Semantic Web ‘History’
• XML (1996-2004)
• RDF (1997-2004)
• RDFS (1998-2004)
• OWL (2002-2004)
• SPARQL (2004- ?)
• However Description Logics since 1985
TU/e technische universiteit eindhoven
Sorts of Applications• Developer Tools
– In order to create, query, visualize and validate Semantic Web Data
– Semantic Web tools are critically important for its success
• End-user applications– Should give instance benefit to providing semantically
enriched data– Should be natural; hiding SW techniques and data
structures
TU/e technische universiteit eindhoven
Semantic Web Tools• Creation Tools
– E.g. Editors, Webforms, etc
– Wrapping of existing data formats
– Natural language extraction, Machine learning, etc
• APIs– For seamless integration of Semantic Web data
structures in different programming languages
• Transformation tools– For exchange of data between applications and users
– E.g. CSS for HTML and XSL(T) for XML
TU/e technische universiteit eindhoven
Semantic Web Tools (2)• Visualization tools
– Visualization of complex graph-structure
– Displaying / hiding details
• Reasoning– Combining information on the Semantic Web can
provide new information
– OWL provides Description Logic• Enables First-Order-Logic reasoning with languages like
Prolog
TU/e technische universiteit eindhoven
End-user Functionality
• Information Sharing– Information need not be communicated to every
application that uses the same info– Communication, syntactic and semantic
interoperability• Collaborative filtering,
– Recommendation systems, pattern discovery, self-information
TU/e technische universiteit eindhoven
End-user Functionality(2)• Data integration
– Create consistent view (e.g. a homogenous presentation) over heterogeneous data-sources
– Adapt data to context
• Personalization
– Propagation of personalization to different applications
– Social Networking
TU/e technische universiteit eindhoven
End-user Functionality (3)
• Searching and Retrieval of Data– Not just keywords, query properties and
relationships between concepts– SQL power for the Web!
• Reasoning– Infer new information– Take natural language into account (e.g.
synonyms, homonyms, antonyms, etc)– Decision Support
TU/e technische universiteit eindhoven
Selection of Developer Tools
TU/e technische universiteit eindhoven
APIs
• HP Jena– (http://jena.sourceforge.net/index.html)
• Sesame– http://www.openrdf.org/
• SWeDE (Eclipse plug-in)– http://owl-eclipse.projects.semwebcentral.org/
• Stanford API (Melnik)– http://www-db.stanford.edu/~melnik/rdf/api.html
TU/e technische universiteit eindhoven
Reasoners
• Racer– http://www.racer-systems.com/index.phtml
• FaCT++– http://owl.man.ac.uk/factplusplus/
• Pellet– http://www.mindswap.org/2003/pellet/index.shtml
• Cwm– http://www.w3.org/2000/10/swap/doc/cwm.html
TU/e technische universiteit eindhoven
Semantic Web Query
• HP Jena– http://jena.sourceforge.net/index.html– RDQL
• Sesame– http://www.openrdf.org/– SeRQL, RQL, RDQL, (SPARQL plug-in)
• Kowari– http://www.kowari.org/– iTQL
TU/e technische universiteit eindhoven
Sesame
“Sesame is an open source RDF database with support for RDF Schema inferencing and querying.”
TU/e technische universiteit eindhoven
“An massively scalable, transaction-safe, purpose-built database or the storage and retrieval of metadata.”
Kowari
TU/e technische universiteit eindhoven
Editors and Visualizers
• Protégé– http://protege.stanford.edu/
• SWOOP– http://www.mindswap.org/2004/SWOOP/
• KAON– http://kaon.semanticweb.org/
• EROS– wwwis.win.tue.nl/~hera/
TU/e technische universiteit eindhoven
TU/e technische universiteit eindhoven
TU/e technische universiteit eindhoven
TU/e technische universiteit eindhoven
TU/e technische universiteit eindhoven
TU/e technische universiteit eindhoven
TU/e technische universiteit eindhoven
TU/e technische universiteit eindhoven
TU/e technische universiteit eindhoven
Selection of End-User Applications
TU/e technische universiteit eindhoven
RDF Site Summary (RSS)
• News publishing mechanism• RSS-aggregators
– Collect different RSS (and XML) ‘feeds’– Enables uniform, personalized view on
heterogeneous data-sources
• Different incompatible versions exist– (Rich Site Summary, Really Simple
Syndication, Atom, etc)
TU/e technische universiteit eindhoven
RDF in Mozilla
• Smart Browsing and Related Links– Displaying data from RDF-database by using Stylesheets (XUL)
• Aurora– Integrate all your stuff in a Web browser
• Flash Panel– Collect important information from various sources (e.g. mail, IM,
RSS-feeds, etc)
• Enabling Inference– Using Prolog. Applications: Inter-schema mappings, Reasoning about
user preferences and profiles, Advanced mail-filtering
Ref: http://www.mozilla.org/rdf/doc/
TU/e technische universiteit eindhoven
End-User Applications (1)
• RDF Calender– http://www.ilrt.bris.ac.uk/discovery/2001/02/calendar/
• Adobe XMP– http://www.adobe.com/products/xmp/main.html
• Photostuff– http://www.mindswap.org/2003/PhotoStuff/
• SMORE– http://www.mindswap.org/2005/SMORE/
• Piggy Bank– http://simile.mit.edu/piggy-bank/
TU/e technische universiteit eindhoven
End-User Applications (2)
• Haystack– http://simile.mit.edu/hayloft/index.html
• FOAF– http://www.foaf-project.org/
• MusicBrainz / AudioScrobbler– http://musicbrainz.org/, http://www.last.fm/
• Hera– http://wwwis.win.tue.nl/~hera
TU/e technische universiteit eindhoven
Rdf-Calendar• EventDiscovery
– How do I find and share RDF calendar documents?• CalendarScraping
– Importing data from other formats• TravelTools, PathCross
– Automatically plan routes based on appointments• Planning and negotiation
– Automatically search for possibilities for appointments and meetings
• AnnounceOMatic– Subscribe to particular kind of events, e.g. conferences
TU/e technische universiteit eindhoven
Adobe XMP
TU/e technische universiteit eindhoven
Adobe Photoshop - XMP
TU/e technische universiteit eindhoven
Photostuff
TU/e technische universiteit eindhoven
TU/e technische universiteit eindhoven
Piggy bank (1)
• FireFox plugin• Brings Semantic Web in Web-browsering• Consists of different steps
– Collect Data– Search and Browse– Pinpoint locations on a map– Tag Information– Combined data– Share Data
TU/e technische universiteit eindhoven
TU/e technische universiteit eindhoven
TU/e technische universiteit eindhoven
Haystack (1)
• Semantic Web browser– “Present Semantic Web data in a integrated
and human presentable way”
TU/e technische universiteit eindhoven
TU/e technische universiteit eindhoven
Friend Of A Friend
TU/e technische universiteit eindhoven
<Person rdf:nodeID="danbri"> <foaf:name>Dan Brickley</foaf:name><foaf:nick>danbri</foaf:nick> <foaf:jabberID>danbri@gnu.minu.nu</foaf:jabberID><foaf:aimChatID>danbri_2002</foaf:aimChatID> <mbox rdf:resource="mailto:danbri@w3.org"/><uranai:bloodtype xmlns:uranai="http://kota.s12.xrea.com/vocab/uranai" >
A+</uranai:bloodtype> <srw:srw>en</srw:srw>
<homepage rdf:resource="http://rdfweb.org/people/danbri/"/> <foaf:dateOfBirth>1972-01-09</foaf:dateOfBirth> <foaf:img rdf:resource="http://rdfweb.org/people/danbri/2000/01/01/Image1.gif"/> <plan>Save the world and home in time for tea.</plan><knows>
<Person> <name>Dean Jackson</name> <rdfs:seeAlso rdf:resource="http://www.grorg.org/dean/foaf.rdf"/> </Person>
</knows> </Person>
TU/e technische universiteit eindhoven
TU/e technische universiteit eindhoven
TU/e technische universiteit eindhoven
Hera Presentation Generator (HPG)CM (Domain model)
AM (Navigation structure)
Profile (User and platform
characteristics)
CMI (Input data)
PM (Layout and style)
Presentation (Web pages)
TU/e technische universiteit eindhoven
HPG - Presentation in Browsers
HTML for PC SMIL
TU/e technische universiteit eindhoven
HPG - Presentation on different devices
HTML for PDA WML
TU/e technische universiteit eindhoven
Examples of Techniques
TU/e technische universiteit eindhoven
Semantic Search
• ‘All papers written by prof. Houben between 2000 and 2004’
Paper
2002
Type
WrittenBy
Name
Houben
Function
Prof.
Publication Year
TU/e technische universiteit eindhoven
Current Search Engines
• Query expression power– Only match words– No relations between query elements
• Not all data is in the document (metadata)• Only searches flat text (HTML,pdf,txt, etc)
– Multimedia files only if imbedded in document with surrounding text (works poorly)
– Structure cannot be exploited to increase expression power
TU/e technische universiteit eindhoven
Exploiting Semantics
• Not only exact structure queries– You do not know the structure you search on– Relevant source structures are heterogeneous
• Use semantics to get more relevant results– Include similar Classes
• E.g. subClassOf, EquivalentClass, etc
– Search Equivalent constructs– Process Language variations
• E.g. Synonyms, Homonyms, Polysemy
TU/e technische universiteit eindhoven
Reasoning
• Reasoning support is important for– checking the consistency of the ontology and the
knowledge– checking for unintended relationships between classes– automatically classifying instances in classes
• Checks like the preceding ones are valuable for – designing large ontologies, where multiple authors are
involved– integrating and sharing ontologies from various sources
TU/e technische universiteit eindhoven
Reasoning Example• Terminology (or T-Box)
– Murder Crime : Fraud– Murderer commit.Murder
– Accountantcommit.Crimecommit.Fraud
• Assertions (or A-Box)– Oswald: Criminal
– KennedyAssassination: Murder
– (Oswald, KennedyAssassination): commited
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Expansion Rules
Ref: Baader, Sattler 2000
TU/e technische universiteit eindhoven
Reasoning Example (2){Murder Crime Fraud, Murderer commit.Murder ,Accountant commit.Crime commit.Fraud}
• Satisfiability (or consistency)– Recursively apply expansion rules– Stop when no more rules applicable or clash occurs
• Clash is an obvious contradiction, e.g., A(x) : A(x)• Concept unsatisfialibity: Murder Fraud = .
• Subsumption– Represents the is-a relation – Check if for all instances i holds that A.i B.i
• Subsumption: Murderer Accountant
TU/e technische universiteit eindhoven
Reasoning Example (3){Oswald: Criminal, KennedyAssassination: Murder,
(Oswald, KennedyAssassination): commited}
• Consistency– Check instances against model– E.g. additional assertion {Oswald:Accountant} would
result in contradiction.• Instance Checking
– Check if for all occurences instances i holds that i A– E.g. Oswald Murderer
TU/e technische universiteit eindhoven
Information Sharing
TU/e technische universiteit eindhoven
User Dependent
Application Dependent
Instance Mapping
Schema A Schema B
maps-from
Instance a Instance b
maps-to
Mapping Module
is-inp
ut-fo
r is-input-for
generates
is-instance-of is-instance-of
Schema Mapping
A B
A+B
generates
TU/e technische universiteit eindhoven
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