Combining RDF and OWL with SOAP for Semantic Web Services

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Combining RDF and OWL with SOAP for Semantic Web
Services

• Yuxiao Zhao
• Programming Environment Lab
• Dept of Computer and Info ScienceLinköping
  University, Sweden
• yuxzh_at_ida.liu.se

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Introduction

• Motivation
• Three levels of combinations and Level 0
• Compare the four levels of semantic integration
• Semantic Web (services) vs. Semantic (Web
  services)
• Conclusions
• Ongoing research

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Motivation

• Semantics in SOAP not in attention
• Adding semantics into SOAP messages may result in
  some benefits
• Likely to enhance flexibility of integration
• Likely to reduce ambiguity

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RDF and OWL

• Web Ontology standards
• RDF/RDFS
• Resource Description Language (subject-predicate-o
  bject)
• RDF schema for RDF vocabulary
• OWL Web Ontology Language
• Enter Recommendation Phase by W3C this February
• Much richer semantics
• Three levels OWL Lite, OWL DL, OWL Full

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Web Service

• SOAP Envelope
• Header (control data)
• Body (payload or transaction data)
• WSDL interface definition
• UDDI
• business entities
• technical models

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Four Levels of Combinations

• Level 0 Internal translation
• Level 1 Simple Reference
• Level 2 Direct Embedment
• Level 3 Semantic SOAP

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Level 0 Internal Translation (1)

• Transform one XML doc in one XSD into another
• Internal means behind Web services
• No change for WSDL and SOAP

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Level 0 Internal Translation (2)
ltorder id 12345gt ltfromgtxxxxlt/fromgt
lttogtyyyylt/togt lt/ordergt ltorder id 12345gt
ltfrom id xxxx/gt ltto id yyyy/gt lt/ordergt
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Level 1 Simple Reference (1)

• SOAP body is a string a URL link to point an
  individual (OWL)
• SOAP body is to use RDF to describe it.
• For example

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Level 1 SOAP Body XSD(2)
ltmreceiveXMLdoc xmlnsm http//www.yuxzh.com
/buyerAware.wsdlgt ltseller
xmlns"http//www.ida.liu.se/yuxzh/ws/soap.xsd"gt
ltaddressgt ltemailgtemail address of the
sellerlt/emailgt ltwebServicegtweb service of the
sellerlt/webServicegt? ltaddress/gt
ltkeywordgt ltontURIgtthe namespace of the
ontologylt/outURIgt? ltwordgtthe word from the
namespace abovelt/wordgt ltposgtPart of Speech
NOUN, VERB, ADV, or ADJ. default
NOUNlt/posgt? ltrequiregttrue/false. Default
truelt/requiregt? lt/keywordgt
lt/sellergt lt/mreceiveXMLdocgt
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Level 1 SOAP Body Ontology (3)

• ltmreceiveOWLIndividual xmlnsmhttp//www.yuxzh.
  com/buyerAware.wsdlgt
• ltseller xmlns"http//www.ida.liu.se/yuxzh/w
  s/soap.xsd"gt http//www.ida.liu.se/yuxzh/o
  ntology/seller/keywords.rdfzhao
• lt/sellergt
• lt/mreceiveOWLIndividualgt

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Level 1 Ontology as message agreement (4)

• Simplicity
• Composition WS1-gtWS2-gtWS3-WS4
• But the receiving WS has to fetch the data
  through the link

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Level 2 Direct Embedment (1)

• Embed an extended individual from an agreed
  ontology instead of pointing a link
• But the content becomes more complex

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Level 3 Semantic SOAP (1)

• SOAP consists of header and body
• Can we build a common SOAP ontology including the
  elements
• Envelope
• Header (Id date role relay etc)
• Body (who act what )
• And different elements from different ontology

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Semantic SOAP WSDL (2)
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Semantic SOAP (3)

• It may be useful for those involving many
  transactions that have to use ID to link them
  together, e.g.,
• product negotiation

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31 Levels of Combinations Table 2
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Semantic Web (services) vs. semantic (Web
services) Table 1
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Summary and Conclusions

• Three combinations of RDF/OWL with SOAP are
  possible to create semantic WS
• Level 1 (Simple Reference) leads to simplicity
  of messaging but it has to fetch the data through
  the link
• Level 2 (Direct embedment) does not fetch the
  data through the link but message type is complex
• Level 3 (Semantic SOAP), useful for those web
  services never met before but want to communicate

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Ongoing Research Testing Phase

• An Open Infrastructure for Building Buyer
  Awareness
• How to specify sellers products simply but
  containing rich semantics
• How to define type of messages between sellers
  and potential buyers
• How to semantically match sellers offers with
  buyers requirements (synonym, polysemy and
  partial matching)

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Thank You for Listening!

• Any questions?

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What are semantics in SWS?

• Semantics in OWL-S
• Grounding with SOAP and WSDL

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New Semantic Web Service

• Build upon Web service
• Add semantic data into SOAP envelope
• RDF/OWL

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Define An Sequence Flexible Interface by OWL Class

• WS is defined by XML Schema, but the sequence is
  fixed
• Advantage sequence can be flexible
• All interfaces for decoupled applications are
  fixed in sequence
• WSDL
• IDL in CORBA