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WEESA WEb Engineering for Semantic web Applications or What I did last Summer

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Separation of Concerns in XML based Web applications. WEESA Mapping XML ... e.g. playtime of all tracks of a music CD to calculate the playtime of the CD. ... – PowerPoint PPT presentation

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Title: WEESA WEb Engineering for Semantic web Applications or What I did last Summer


1
WEESA WEb Engineering for Semantic web
ApplicationsorWhat I did last Summer
  • PhD. Seminar
  • Gerald Reif
  • October, 27 2004, Vienna, Austria

2
Outline
  • Engineering Web Applications
  • Semantic Annotation
  • Separation of Concerns in XML based Web
    applications
  • WEESA Mapping XML Schema to Ontologies
  • WEESA Mapping Example
  • WEESA in a Cocoon Transformer
  • Conclusions and Future Work

3
Web Engineering
  • Subdiscipline of Software Engineering
  • Focus Systematic cost efficient development,
    maintenance, and evolution of Web applications.
  • Output Static/dynamic Web pages to be displayed
    in a Web browser.
  • Human-understandable Web pages.
  • Semantic Web machine-understandable meta-data
    representation is needed.

4
Semantic Annotation
  • Adding machine readable meta-data to Web
    applications.
  • Problems
  • Time consuming additional task (cost issue)
  • Peoples adding the meta-data are typically not
    the one that profit from its existence.
  • Granularity of the information on the Web page
    does not meet the terms in the ontology.
  • Tool support mostly for static pages.

5
Tools for Semantic Annotation
  • SHOE Knowledge Annotator
  • Form based GUI to annotate static Web pages.
  • Granularity problem.
  • SMORE (Semantic Markup, Ontology and RDF Editor)
    from the MindSwap project
  • Embedded HTML editor and ontology browser.
  • OntoMat from the CREAM project
  • Similar to SMORE but supports also dynamic Web
    pages.
  • Database is annotated instead of HTML document.
  • Disadvantage Decoupled from the Web application
    design process.

6
Related Work Semantic Web Engineering
  • Semantic annotation part of the design process of
    the Web application.
  • Extension of WSDM (Web Site Design Model)
  • Web pages are based on the definition of object
    chunks.
  • Object chunks are linked to concepts in the
    ontology.
  • Possibility to concatenate object chunks to meet
    the ontology's granularity. (inflexible)
  • Support for dynamic Web sites. (Mapping between
    DB queries and object chunks.)

7
Semantic Web Applications
  • Web applications that offer not only HTML pages,
    but also a meta-data (RDF) description of the
    content.
  • Parts of the content are stored two times
  • On the HTML page
  • In the RDF description
  • Consistency problems when maintaining the Web
    application.

8
Separation of Concerns
  • Defines strict roles in the development process
    and enable parallel development.
  • Common concerns
  • Content
  • Graphical appearance
  • Business logic
  • For Semantic Web applications a new concern is
    needed
  • Meta-data concern

9
XML based Web Applications
  • Many Web applications are based on XML and XSLT.
  • Content editors
  • Layout designers
  • Logic Programmers
  • Generate RDF
  • Overcome the inconsistency problem

Knowledge about the structure and
elements/attributes of the XML document
10
WEESA Mapping
  • WEESA WEb Engineering for Semantic web
    Applications

WEESA mapping definition
XML Schema
Ontology
Design Level
valid
uses tems
RDF Description
XML Document
generates
Instance Level
generated via XSLT
included in the ltheadgt
HTML Page
11
WEESA Mapping definition
  • Goal Fill the RDF triples with data
  • Constant values
  • e.g. reference to a class in the ontology
  • XPath expressions (one-to-one)
  • to select the content of an element/attribute
  • Return value of a Java method
  • e.g. XML document defines the begin and duration
    of an event, the ontology provides properties for
    begin and end time.
  • The set of XPath mathces as parameter e.g.
    playtime of all tracks of a music CD to calculate
    the playtime of the CD.
  • Resource references
  • Unique resource identifiers
  • Support for anonymous resources
  • Support for variables

12
Event Example XML Document
  • lt?xml version"1.0" encoding"UTF-8"?gt
  • ltalbum id"album_1234"gt
  • ltartistgtAlanis Morissettelt/artistgt
  • ltnamegtAlanis Unpluggedlt/namegt
  • ltpricegt9.99lt/pricegt
  • lttracksgt
  • lttrack number"1"gt
  • ltnamegtYou Learnlt/namegt
  • lttimegt422lt/timegt
  • lt/trackgt
  • lttrack number"2"gt
  • ltnamegtJoining Yoult/namegt
  • lttimegt509lt/timegt
  • lt/trackgt
  • lt!-- ... --gt
  • lttrack number"12"gt
  • ltnamegtUninvitedlt/namegt
  • lttimegt437lt/timegt
  • lt/trackgt

13
Event Example WEESA mapping
ltresourcesgt ltresource id"album"gt ltmethodgt
ltnamegtcom.example.addPrefixlt/namegt
ltparam const"http//example.com/album"
type"java.lang.String"/gt
ltparam xpath"/album/_at_id" type"java.lang.String
"/gt lt/methodgt lt/resourcegt ltresource
id"track" anonymous"yes" var"track_id"
xpath"/album/tracks/track/_at_number"/gt lt/res
ourcesgt
  • lt?xml version"1.0" encoding"UTF-8"?gt
  • ltmapping xmlns "http//www.infosys.tuwien.ac.at/m
    apping"gt
  • ltresourcesgt
  • .
  • .
  • .
  • lt/resourcesgt
  • lttriplesgt
  • .
  • .
  • .
  • lt/triplesgt
  • lt/mappinggt

lttriplegt ltsubject ref"album"/gt ltpredicate
const"http//www.w3.org/1999/02/22-rdf-syntax-ns
Type"/gt ltobject const"http//example.com/MyTune
sAlbum"/gt lt/triplegt lttriplegt ltsubject
ref"album"/gt ltpredicate const"http//example.c
om/MyTuneshasTrack"/gt ltobject
ref"track"/gt lt/triplegt lttriplegt ltsubject
ref"track"/gt ltpredicate const"http//example.c
om/MyTunestrackNumber"/gt ltobject
const"track_id"/gt lt/triplegt
14
WEESA as Cocoon Tansformer
  • Look back on the overall picture

WEESA mapping
XML Schema
Ontology
Design Level
valid
uses tems
RDF Description
XML Document
generates
Instance Level
generated via XSLT
references
HTML Page
15
Cocoon WEESA ReadDOMTransformer
Cocoon Pipeline
Generator
XML Document
Bussines Logic XSP, JSP, Filter, SQL, ect.
SAX Events
Transformers
SAX Events
XSLT Transformer
XSLT Stylesheet
SAX Events
Serializer
HTML RDF/XML
16
Cocoon WEESA Transformer
Cocoon Pipeline
Generator
XML Document
SAX Events
Transformer
Bussines Logic SQL Queries, XSP, JSP,
Filtering, etc
Transformer
SAX Events
WEESA Transformer
WEESA Mapping Definition
XML to RFD transformation
SAX Events
Serializer
RDF/XML Document
17
Future Work
  • Currently testing the mapping in the Wiener
    Festwochen (Vienna International Festival) case
    study.
  • User interface (Part of it done ?)
  • Meta-data model of the whole Web application
  • Mapping for individual pages
  • The accumulation of individual RDF descriptions
    leads to the RDF representation of the whole Web
    application.
  • Mapping for single pages can be done on the fly
    for the Web application it has to be
    pregenerated.
  • Use of the meta-data on the client side.

18
Conclusion
  • Mapping from XML Schema to ontologies allows
    efficient design of Semantic Web applications.
  • Overcome the inconsistency problem
  • WEESA mapping can be used to automatically
    generate semantically tagged Web pages from XML
    content documents.
  • Simple integration in the Apache Cocoon Web
    application framework.

19
Questions
  • Thank you, for your attention.
  • Any Questions?
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