Exploiting Semantic of Web Services through ebXML Registries

1
Exploiting Semantic of Web Services through ebXML
Registries

• Asuman Dogac
• Middle East Technical University
• 06531 Ankara Turkey

2
The Aim of the Tutorial

• The aim is to make
• the involved topics easily digestible
• so that the companies can judge for
• themselves the possible benefits
• of these technologies

3
Outline

• Motivation Why do we need the semantics of Web
  services?
• Means of expressing semantic Ontology and
  Ontology Description Languages
• XML in brief Why XML is useful?
• Web Interaction Evolution
• Web services, SOAP, WSDL and UDDI
• Semantic Support of Web Services in UDDI
  Registries
• ebXML A Brief Overview
• How to Exploit Web Services Semantics through
  ebXML?
• OWL-S

4
Motivation Why do we need the semantics of Web
services?
5
Why do we need Web Service Semantics?

• In order to exploit services in their full
  potential their properties must be defined
• The methods of charging and payment
• The channels by which the service is requested
  and provided
• Constraints on temporal and spatial aspects
• Availability
• Service quality
• Security, trust and rights attached to a service

6
Why do we need Web Service Semantics?

• To be able to describe service properties and
  later search for services according to their
  properties
• This search needs to be done in a machine
  processable and interoperable manner
• Some reasoning capabilities will also help!

Defining Service Properties Through Ontology
Languages
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A Motivating Example
A Company In Turkey
Needs to find all services which sell
Delivery should be within a week
The process should be fully automated no
human interaction
Desktop With Memory 256 MByte Speed 2 GHertz
Payment method should be credit card
Made In Italy
8
To be continued
9
Ontology
10
What is an Ontology?
An explicit formal specification of the terms in
the domain and relations among them. - Noy
and McGuinness, Ontology Development 101

• The word ontology comes from the Greek ontos
  (being) and logos (word)
• An ontology describes objects and concepts as
  classes
• These classes are arranged in a hierarchy, and
  then class attributes and relationships are
  described with properties

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An Example RDF Schema
ltrdfsClass rdfIDCrimes"gt lt/rdfsClassgt
ltrdfsClass rdfIDRobbery"gt
ltrdfssubClassOf rdfresource"Crimes"/gt lt/rdfsC
lassgt

ltrdfsClass rdfIDTerrorism"gt
ltrdfssubClassOf rdfresource"Crimes"/gt lt/rdfsC
lassgt
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RDF Properties
description
ltrdfsProperty rdfIDdescription"gt
ltrdfsdomain rdfresource"Crime"/gt
ltrdfsrange rdfresourcehttp//www.w3.org/2000
/01/rdf-schemaLiteral"/gt lt/rdfsProperty gt

• ltrdfsProperty rdfIDsuspect"gt
• ltrdfsdomain rdfresource"Robbery"/gt
• ltrdfsrange rdfresourceThiefgt
• lt/rdfsProperty gt

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RDF

• RDF fixes the syntax and structure of describing
  metadata through RDF Syntax
• It allows meaning to be defined and associated
  with data through RDF Schema
• RDF Schema facilities to define domain specific
  ontologies

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Why use an ontology?

• A common vocabulary
• Ability to define relationships among classes,
  properties and instances
• Automated Processing
• Reasoning!

15
Ontology Languages and OWL
DAMLDarpa Agent Markup Language
OIL Ontology Inference Layer (Commission
Project)
DAMLOIL
RDF (Resource Description Framework)
OWL Web Ontology Language (Being Standardized
by W3C)
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OWL RDF Schema more

• All of the elements/attributes provided by RDF
  and RDF Schema can be used when creating an OWL
  document

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What do we gain from semantics?
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An Example eGovernment

• Finger prints from a robbery scene identified
  John Smith as the suspect
• Here is the police report on the robbery

ltRobbery rdfID"report-2003-10-23-xyz"gt
ltdescriptiongt...lt/descriptiongt ltsuspectgt
ltThief rdfabout"http//www.ministryOfInterior.go
v/criminalsJohn_Smith"/gt lt/suspectgt lt/Robbery
gt
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An Example eGovernment

• Later in the day a police gives a person a
  ticket for speeding
• The driver's license showed the name John Doe
• Here is the police report on the speeder

ltSpeeding rdfID"report-2003-10-23-abc"gt
ltdescriptiongt...lt/descriptiongt ltdrivergt
ltSpeeder rdfabout"http//www.ministryOfInterio
r/criminalsJohn_Doe"/gt lt/drivergt lt/Speedinggt
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OWL Classes

• Ministry of Interior has defined ontologies for
  their information in OWL
• For example

ltowlClass rdfIDCrimes"gt lt/owlClassgt
ltowlClass rdfIDRobbery"gt
ltrdfssubClassOf rdfresource"Crimes"/gt lt/owlCl
assgt

ltowlClass rdfIDTerrorism"gt
ltrdfssubClassOf rdfresource"Crimes"/gt lt/owlCl
assgt
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OWL Classes

• Ministry of Interior has also defined the
  following classes
• For example

ltowlClass rdfIDCriminals"gt lt/owlClassgt
ltowlClass rdfIDThief"gt
ltrdfssubClassOf rdfresource"Criminals"/gt lt/owl
Classgt

ltowlClass rdfIDTerrorists"gt
ltrdfssubClassOf rdfresource"Criminals"/gt lt/owl
Classgt
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OWL Properties

• ltowlDatatypeProperty rdfIDdescription"gt
• ltrdfsdomain rdfresource"Crime"/gt
• ltrdfsrange rdfresourcehttp//www.w3.org/2001
  /XMLSchemaLiteral"/gt
• lt/owlDatatypeProperty gt
• ltowlObjectProperty rdfIDsuspect"gt
• ltrdfsdomain rdfresource"Robbery"/gt
• ltrdfsrange rdfresourceThiefgt
• lt/owlObjectProperty gt
• ltowlObjectProperty rdfIDdriver"gt
• ltrdfsdomain rdfresource"Speeding"/gt
• ltrdfsrange rdfresourceSpeeder"/gt
• lt/owlObjectProperty gt

description
driver
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Any Relationship between the Thief and the
Speeder?
Ministry of Interior keeps the OWL descriptions
of their files
ltCriminals rdfabout" http//www.ministryOfInter
ior/criminalsJohn_Doe "gt ltowlsameAs
rdfresource" http//www.ministryOfInterior.gov/
criminalsJohn_Smith "/gt lt/Criminalsgt
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How can this be achieved? owlsameAs property
helps!
Inference The Thief and the Speeder are one and
the same!

• OWL provides a property (owlsameAs) for
  indicating that two resources (e.g., two people)
  are the same

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XML in Brief
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XML and Semantics

• XML gives meaning to data but this is not the
  semantics we get through ontologies
• Semantics is commonly agreed class hierarchies
  with properties

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Tagging Data in XML

• ltPONumbergt 1234ABCD lt/PONumbergt

An Element

• Considering the content only, it is not possible
  to understand what 1234ABCD stands for
• The tag name PONumber intuitively tells that the
  content is a purchase order number
• Tagged elements may be nested to any depth to
  provide structured data, or may be repeated to
  represent a list of values

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Why XML?
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Giving Meaning and Structure to Data
Start Tag
Start Tag

• ltPurchaseOrderRequestgt
• ltPONumbergt1234ABCD lt/PONumbergt
• ltPurchaseOrderDategt20030601lt/PurchaseOrderDategt
  
• ltLineItemgt
• ltItemEAN_Identification no9344 /gt
  
• ltQuantityOrderedgt 16 lt/QuantityOrderedgt
  
• ltUnitPricegt 95 ltUnitPricegt
• lt/LineItemgt
• ltLineItemgt lt/LineItemgt
• lt/PurchaseOrderRequestgt

An Element
Another Element
An Attribute
Data
End Tag
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Giving Structure to Data
PurchaseOrderRequest
PurchaseOrderDate
LineItem
PONumber
ItemEAN_Identification
QuantityOrdered
UnitPrice
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Extensibility in XML

• Anyone can invent new tags and attach a meaning
  to those tags
• For example
• ltHandHeldDevicegt This devicelt/HandHeldDevicegt
• ltMobileDevicegt This devicelt/MobileDevicegt
• But if every user creates its own XML definition
  for describing his data, it is not possible to
  achieve interoperability

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Agreement on tags is necessary

• In other words, a tagged document is not very
  useful without some kind of agreement on the tags
  among inter-operating applications

Mobile Device
Hand Held Device
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Standardizing XML Documents

• There are very many efforts in this respect
• Common Business Library (xCBL)
• RosettaNet
• Web Service standards
• ebXML
• HL7 for heath care
• Almost any standard that you can think of is
  being developed in XML

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Many Public Domain XML Software For Example XML
DOM Parser
A parser validates and makes the data contained
in an XML document available to the application
35
XSLT Processor

• Converts an XML document to another form
• An XSL style sheet is a set of transformation
  instructions for converting a source XML document
  to a target document

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XML vs EDI
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XML vs EDI
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XML vs EDI
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Why use XML?

• It is a universally accepted standard way of
  structuring data (syntax)
• It is a W3C recommendation (W3C World Wide Web
  Consortium)
• The marketplace supports it with a lot of
  free/inexpensive tools

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Web Interaction Evolution How have we reached to
Web services?
42
Earliest Days of Web
HTML over HTTP
A Web Browser like Netscape or Explorer
Static Document Exchange No processing on the
server or on the browser!
WEB
A Web Server like Apache Server

• Web has a client/server architecture, where a
  browser runs on the client such as Netscape or
  Explorer and a Web server like Apache server
  runs on the server machine
• In the early days of the Web, there was no
  processing either on the client or on the server
• A user accessed only static documents which are
  the pages that exist on the Web server and are
  simply delivered to the Web browser
• However in 1995 W3C published HTML 2.0 which
  included forms that made it possible to use Web
  interactively

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Interaction through Web Forms
Common Gateway Interface
A Web Form (HTML)
Back End Processing
Submit
WEB

• A Web form, is an HTML page with one or more data
  entry fields and a mandatory Submit button
• When the submit button is clicked, the form's
  data contents are send to a Web server
• The server invokes the program or resource named
  in the URL and passes the method request and its
  parameters to the back-end program using a
  protocol called the Common Gateway Interface
• The back-end program executes the request and
  returns the results in HTML format to the Web
  server using the CGI protocol
• The Web server returns the result to the client
  Pages (called dynamic pages)

44
More Advanced Forms of Interaction

• Web Browser-side Processing
• The processing on the client side basically
  involves validating user input, and interactivity
  with the server
• Some of the well-known browser-side processing
  technologies are as follows
• Scripts A script is a program that may accompany
  an HTML document
• The program executes on the client's machine when
  the document is downloaded, or at a later time
  when a link is activated
• It increases the interactivity provided by HTML
• The most popular scripting languages are Java
  Script and VBScript
• Applets Applets are programs that require a Web
  browser to run
• The ltAppletgt tag is embedded in a Web page and
  identifies the applet to be run
• When the page is accessed by a user, the applet
  is automatically downloaded from the server and
  runs on the client machine

45
More Advanced Forms of Interaction

• Web Server-side Processing
• Web server-side processing is used in generating
  customized responses for the user by accessing
  databases
• There are several technologies for server-side
  processing
• The Java Servlet API allows Web developers to
  extend the functionality of a Web server by
  writing small Java programs called Servlet that
  interact with the Web server through a
  well-defined API
• Server-side applications can also be written
  using JavaBeans
• JavaBeans are portable, platform independent and
  hence reusable software components written in
  Java that perform well-defined tasks
• Java Server Pages are another platform-independent
  alternative for generating dynamic content on
  the server side
• PHP is an open source server-side scripting
  language which is written specifically for
  interacting with the Web
• ASP is a server-side processing technology from
  Microsoft

46
Web Services

• Existing applications can be wrapped as Web
  services
• Client and Service can use different platforms
  and programming languages
• Services can be composed to make composite
  services

47
Summary Evolution of Web Interaction
48
Web services, SOAP, WSDL and UDDI
49
What is a Web Service?
To put it simply, Web services are applications
that interact with each other using Web standards
Web Service
XML
Client Application
WEB

• A Web Service is an interface that describes
• a collection of operations
• that are network-accessible
• through standardized XML messaging

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Web Services

• A Business function
• made available via Internet by a service
  provider, and
• accessible by clients that could be human users
  or software applications
• A software application
• Identified by a URI
• Its interfaces and binding are capable of being
  defined, described and discovered by XML
  artifacts and
• Supports direct interactions with other software
  applications
• Using XML based messages via Internet-based
  protocols

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W3C Description of a Web Service

• A Web service is a software system designed to
  support interoperable machine-to-machine
  interaction over a network
• It has an interface described in a
  machine-processable format (specifically WSDL)
• Other systems interact with the Web service in a
  manner prescribed by its description using
  SOAP-messages, typically conveyed using HTTP with
  an XML serialization in conjunction with other
  Web-related standards

52
Some Use Examples

• An insurance policy service to insure the
  products being shipped
• A financing service to ensure payment according
  to vendor terms
• A health-care service to access health-care
  records

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Web Service Model
Service Registry (ebXML or UDDI) - Web service
descriptions
Discover service
Publish service
Service Consumer
Service Provider - Web service - Service
Description in WSDL
Invoke service through SOAP
54
Web Services

• The Web Services Reference Model
• Service Provider
• Service Registry
• Service Consumer
• Major Standards
• WSDL (Web Services Description Language)
• SOAP (Simple Object Access Protocol)
• UDDI (Universal Description, Discovery and
  Integration) registries
• ebXML (Electronic Business XML)

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Why Web Services?

• For B2B interactions, applications need to talk
  to each other on the Web Interoperability is
  needed
• A change in an application should not effect the
  apps it is talking to
• Web services provide these through WSDL and SOAP
• WSDL is the established public contract with the
  outside world

WSDL and SOAP Public contract with the outside
world
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WSDL Provides only the Technical Description of
the Service!
Web Service Description Language
defines
Web Service
Service Consumer
uses
57
WSDL does not describe Web service semantics
Ontologies do!
Semantic description of the properties of a
service
Web Service Description
defines
uses
Web Service
Service Consumer
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WSDL Structure
Service
Where to access it
Port (e.g. http//host/svc)
Port
How to access it
Binding (e.g. SOAP, JMS, direct call)
Binding
Operation An Exchange of Messages between a
service Requestor and a Service provider
Abstract definition of the service (set
of Operations)
Abstract interface
portType
operation(s)
inMesage
outMessage
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Web Services Description Language
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XML Messaging SOAP

• The current standard for XML Messaging is Simple
  Object Access protocol (SOAP)
• Applications typically communicate with Web
  services via SOAP messaging
• Typically HTTP is used as RPC transport
• XML is used as RPC encoding scheme

61
SOAP

• SOAP consists of three parts
• an envelope that defines what is in a message,
• a set of encoding rules for expressing instances
  of application-defined data types, and
• a convention for representing remote procedure
  calls (RPC) and responses
• SOAP can be used in combination with by a variety
  of network protocols such as HTTP, SMTP, FTP, MQ
  or RMI over IIOP

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SOAP over HTTP
HTTP POST Message
SOAP Endpoint Reference
XML Message
SOAP Payload
SOAP Envelope
SOAP Header
SOAP Body
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SOAP Endpoint Reference
IP Host Address
TCP Port No
Object Endpoint ID
144.122.230.16
80
/ProductCataloggetPrice
POST /ProductCatalog HTTP/1.0 Host
http//www.srdc.metu.edu.tr Content-Type
text/xml charset"utf-8" Content-Length
500 SOAPAction http//www.srdc.metu.edu.tr/P
roductCataloggetPrice"
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SOAP Body

• ltSOAP-ENVHeader /gt
• ltSOAP-ENVBodygt
• ltsgetPrice xmlnss"http//www.srdc.metu.edu.tr
  /ProductCatalog"gt
• ltproduct_name xsitype"xsdstring"gtPalm
  Pilotlt/product_namegt
• lt/sgetPricegt
• lt/SOAP-ENVBodygt
• lt/SOAP-ENVEnvelopegt

Method Name
Input Parameter
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SOAP Response

• HTTP/1.0 200 OK
• Content-Type text/xml charset"utf-8"
• Content-Length 400
• ltSOAP-ENVEnvelope
• xmlnsSOAP-ENV" http//schemas.xmlsoap.org/
  soap/envelope/"
• SOAP-ENVencodingStyle" http//schemas.xmls
  oap.org/soap/encoding"
• xmlnsxsi"http//www.w3.org/1999/XMLSchema-
  instance"
• xmlnsxsd"http//www.w3.org/1999/XMLSchema"
  gt
• ltSOAP-ENVHeader /gt
• ltSOAP-ENVBodygt
• ltsgetPriceResponse xmlnss"http//www.srdc.me
  tu.edu.tr/ProductCatalog"gt
• ltproduct_price xsitype"xsdfloat"gt2000.lt/prod
  uct_pricegt
• lt/sgetPriceResponsegt
• lt/SOAP-ENVBodygt
• lt/SOAP-ENVEnvelopegt

Standard Suffix
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WS-Security

• Microsoft and IBM partnership
• Enhancement of SOAP messages to provide
• Message integrity
• Message confidentiality
• Message authentication

http//www-106.ibm.com/developerworks/library/ws-s
ecure/
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Semantic Support of Web Services in UDDI
Registries
68
Web Service Model
UDDI Web Service Registry - Web service
descriptions
Discover service
Publish service
Service Consumer
Service Provider - Web service - Service
Description in WSDL
Invoke service through SOAP
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Registry APIs (SOAP Messages)

• Publishers API
• Save
• save_business
• save_service
• save_binding
• save_tModel
• Delete
• delete_business
• delete_service
• delete_binding
• delete_tModel

• Inquiry API
• Find
• find_business
• find_service
• find_binding
• find_tModel
• Get Details
• get_businessDetail
• get_serviceDetail
• get_bindingDetail
• get_tModelDetail

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Business Registration

• XML document
• Created by end-user company (or on their behalf)
• Can have multiple service listings
• Can have multiple taxonomy listings

73
Business categories in UDDI

• 3 standard taxonomies in V1
• Industry NAICS - North American Industrial
  Classification Scheme (Industry codes - US Govt.)
• Product/Services UN/SPSC - Universal Standard
  Products and Services Classification (ECMA)
• Location ISO 3166 Geographical taxonomy

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ISO 3166 Codes (Countries)(http//www.iso.ch/iso/
en/prods-services/iso3166ma/)
75
North American Industry Classification System
(NAICS)
76
United Nations Standard Products Services Code
(UNSPSC)
77
Remember the Motivating Example
A Company In Turkey
Needs to find all services which sell
Delivery should be within a week
The process should be fully automated no
human interaction
Desktop With 256 MByte Speed 2 GHertz
Payment method should be credit card
In Italy
78
If there is such a service, how can we find it
through UDDI Registries?

• find_service (2GHertz, 256 MByte, 2 years, 1
  Week, Credit_Card, Italy)

How to find the Service in UDDI Registry?
UDDI Registry MyService(Speed,Memory, Battery_Lif
e, DeliveryTime, Payment_Method, Location)
79
UNSPSC Codes for Computers (http//eccma.org/unsps
c/browse/43.html)

• -43.17.18.00 Computers commodity
• -43.17.18.01 Notebook computers commodity
• -43.17.18.02 Docking stations commodity
• -43.17.18.03 Workstations or desktop computers
  commodity
• -43.17.18.04 Personal digital assistants
  (PDAs) or pen based computers commodity
• -43.17.18.05 Mainframe computers commodity
• -43.17.18.06 Servers commodity
• -43.17.18.07 Port replicators commodity
• -43.17.18.08 Minicomputers commodity
• -43.17.18.09 Point of sale (POS) terminals
  commodity
• -43.17.18.22 Supercomputers

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Taxonomy vs. OntologyAn Example Taxonomy UNSPSC
43.17.18.00 Computers commodity
43.17.18.03 Workstations or desktop computers
commodity
81
If there is such a service, how can we find it
through UDDI Registries?

• If a service puts the tModel key corresponding to
  43.17.18.03 Workstations or desktop computers
  commodity in its category bag
• THEN
• We know that this service is related with
  computers
• BUT How about the properties of the product?
  Memory, Speed?

82
Current Semantic Support for Web Services in UDDI
Registries

• To find services which sell desktops in Italy
  put
• tModel key corresponding to ISO 3166 and Italy
• in the category bags of such services
• How about the other properties of service we are
  looking for?
• Payment method? Delivery time? Product properties?

83
Summary and Conclusions on the semantic support
by UDDI registries

• UDDI provides very limited semantic support for
  Web services!

84
ebXML A Brief Overview
85
ebXML

• A joint global initiative by
• UN/ CEFACT United Nations Center For Trade
  Facilitation And Electronic Business
• OASIS Organization for the Advancement of
  Structured Information Standards
• United Nations Center for Trade Facilitation and
  Electronic Business
• Sets worldwide policy and technical development
  in trade facilitation and electronic business
• Developed international EDI standard, UN/ EDIFACT
• The initiative leverages from the success of EDI
  in large businesses, and intends reaching small
  and medium enterprises

86
ebXML Architectures functional components

• Business Process Specification Schema (BPSS)
• Trading Partner Information
• Collaboration Protocol Profile CPP
• Trading Partner Agreement
• Collaboration Protocol Agreement CPA
• Registry/Repository
• Messaging Service
• Core Components

87
An Overview of Functional Components in ebXML
ContextFor
ebXML Business Process Specifications
Business Document Specification
ebXML Core Components
BuiltWith
ReferenceTo
Repository
Implement other Partner Role
Implement one Partner Role
Business Service Interface
Business Service Interface
CPP
CPP
CPA
88
Company A
1 Request Business Details
ebXML Registry
2 Build Local System
3 Register Company Information
5 Download Scenarios and Profiles
6 Agree on Business Arrangements
4 Query about Company A
7 Do Business Transactions!
Company B
ebXML compliant system
89
ebXML Summary and Implementation Status

• Currently ebXML compliant registries are
  available, for example, OASIS ebXML Registry
  Reference Implementation Project (ebxmlrr),
  http//ebxmlrr.sourceforge.net/

90
How to Exploit Web Services Semantics through
ebXML?
91
Where to store the generic semantics of the
services?

• An ebXML registry allows to define semantics
  basically through two mechanisms
• It allows properties of registry objects to be
  defined through slots and,
• Metadata can be stored in the registry through a
  classification mechanism

92
ebXML Registry Information Model (RIM)
RegistryObject
ClassificationNode
Classification
Association
RegistryEntry
RegistryPackage
ExtrinsicObject
Service
ClassificationScheme
93
Classifying a Service in ebXML Registries
94
Why to relate services advertised with the
generic ontology classes?

• By relating a service advertised with a node in
  classification hierarchy, we make the service an
  explicit member of this node
• The service also inherits the well-defined
  meaning associated with this node as well as the
  generic properties defined for this node

95
An Example
MyService is a SellService because it is
classified under it
MyService inherits the property DeliveryTime
because it is a subClass of SellService
96
How to Define a Classification Hierarchy in ebXML?

• ltrimClassificationScheme id WebService
  isInternal'true' nodeType'UniqueCode' gt
• ltrimNamegt
• ltrimLocalizedString value
  WebService'/gt lt/rimNamegt
• ltrimDescriptiongt
• ltrimLocalizedString value 'This is a sample
  WebServicescheme'/gt
• lt/rimDescriptiongt
• ltSlot name paymentMethod' slotType
  'StringList/gt
• lt/rimClassificationSchemegt

• ltrimClassificationNode id SellService
  parent WebService'gt
• ltrimNamegt
• ltrimLocalizedString
  value SellService' /gt lt/rimNamegt
• ltrimDescriptiongt
• ltrimLocalizedString
  value ''/gt
• lt/rimDescriptiongt
• ltSlot name deliveryTime' slotType
  'StringList/gt
• lt/rimClassificationNodegt

97
Relating a Web service Advertised with Service
Ontology in ebXML
Such a classification indicates that MyService is
a SellService!
98
Classifying a Service With Multiple Hierarchies
in an ebXML Registry
ServiceToIndustryClassification Classification
ServiceToIndustryClassification Classification
classifiedObject
classifiedObject
classification Node
classification Node
MyService
SellService ClassificationNode
Laptop ClassificationNode
classifiedObject
classification Node
ServiceToIndustryClassification Classification
Italy ClassificationNode
99
SubmitObjectRequest which declares the semantic
of MyService and relates it with the Sell
Service

• lt?xml version '1.0' encoding 'UTF-8'?gt
• ltSubmitObjectsRequest gt
• ltrimLeafRegistryObjectListgt
• ltService id"MyService"gt
• ltNamegt ltLocalizedString lang"en_US" value
  MyService"/gt lt/Namegt
• ltClassification classificationNodeSellService
  ClassifiedObject "MyService" /gt
• ltSlot name deliveryTime'gt
• ltValueListgt ltValuegt1 Week lt/Valuegt
  lt/ValueListgt lt/Slotgt

100
An Example SubmitObjectRequest (Contd)

• ltServiceBinding accessURI"http//www.sun.com
  /ebxmlrr/registry/nameSpaceI ndexer"gt
• ltSpecificationLink specificationObject"wsdl"gt
  lt/SpecificationLinkgt lt/ServiceBindinggt
  lt/Servicegt
• ltExtrinsicObject id"wsdl" mimeType"text/xml"gt
  lt/ExtrinsicObjectgt
• lt/rimLeafRegistryObjectListgt
• lt/SubmitObjectsRequestgt

101
How do we locate Web services according to their
semantics in an ebXML compliant registry?
102
A Filter Query Retrieving all the services
classified by SellService Node with Delivery Time
1 Week

• ltAdhocQueryRequest gt
• ltResponseOption returnType "LeafClass"
  returnComposedObjects "true" /gt
• ltFilterQuerygt ltServiceQuerygt
  ltClassifiedByBranchgt
• ltClassificationNodeQuerygt ltNameBranchgt
  ltLocalizedStringFiltergt
• ltClausegt ltSimpleClause leftArgument
  "value"gt
• ltStringClause stringPredicate
  "Equal"gtSellService lt/StringClausegt
• lt/SimpleClausegt lt/Clausegt
  lt/LocalizedStringFiltergt lt/NameBranchgt
• lt/ClassificationNodeQuerygt
  lt/ClassifiedByBranchgt
• ltSlotBranchgt ltSlotFiltergt ltClausegt
  ltSimpleClause leftArgument "name_"gt
• ltStringClause stringPredicate "Equal"gt
  deliveryTime lt/StringClausegt
• lt/SimpleClausegt lt/Clausegt lt/SlotFiltergt
• ltSlotValueFiltergt ltClausegt ltSimpleClause
  leftArgument "value"gt
• ltStringClause stringPredicate "Contains"gt 1
  Week lt/StringClausegt
• lt/SimpleClausegt lt/Clausegt lt/SlotValueFiltergt
  lt/SlotBranchgt
• lt/ServiceQuerygt lt/FilterQuerygt
  lt/AdhocQueryRequestgt

103
Summary and Conclusions on the Semantic support
provided by ebXML

• Semantic information can play two major roles in
  the Web services area
• One is to provide a source of shared and
  precisely defined terms which can be used to
  dynamically discover, compose and monitor
  services
• The other is to reason about the semantic
  information
• ebXML class hierarchies can achieve the first
  role
• However, for the second role, we need the power
  of ontology languages and reasoners

104
OWL-S
105
OWL-S Defines an Upper Ontology for Web Services
in OWL
describedByHow it works
106
The next steps

• The future work involves defining the semantics
  of Web services through Ontology Languages like
  OWL-S
• And exploiting such service ontologies through
  service registries
• There are already some work in this direction

107
Thank you for your attention!