asuman dogacechallenges, bologna, october 23, 20031/101 exploiting semantic of web services through...

Asuman Dogac eChallenges, Bologna, October 23, 2003

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Exploiting Semantic of Web Services through ebXML RegistriesAsuman 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


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Motivation: Why do we need the semantics of Web services?


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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


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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

Needs to find all services which

sell …

Desktop With Memory 256 MByte Speed 2 GHertz

Made In Italy Payment methodshould be creditcard

Delivery shouldbe within a week

The process should befully automated: no humaninteraction

A CompanyIn Turkey


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To be continued…


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Ontology


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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

Class

Subclass

Subclass

properties properties


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An Example RDF Schema

Crimes

Robbery Speeding Terrorism

<rdfs:Class rdf:ID=“Crimes"> </rdfs:Class>

<rdfs:Class rdf:ID=“Robbery"> <rdfs:subClassOf rdf:resource="#Crimes"/></rdfs:Class>

<rdfs:Class rdf:ID=“Terrorism"> <rdfs:subClassOf rdf:resource="#Crimes"/></rdfs:Class>

…


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RDF Properties

<rdfs:Property rdf:ID=“suspect"> <rdfs:domain rdf:resource="#Robbery"/> <rdfs:range rdf:resource=“#Thief>

</rdfs:Property >

suspect

Robbery Thief

Crimes Literal

description

<rdfs:Property rdf:ID=“description"> <rdfs:domain rdf:resource="#Crime"/> <rdfs:range rdf:resource=“http://www.w3.org/2000/01/rdf-schema#Literal"/>

</rdfs:Property >


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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?

1. A common vocabulary

2. Ability to define relationships among classes, properties and instances

3. Automated Processing

4. Reasoning!


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Ontology Languages and OWL

DAML:Darpa Agent Markup Language

OIL: Ontology Inference Layer (Commission Project)

DAML+OIL

OWL: Web OntologyLanguage (Being

Standardized by W3C)

RDF (ResourceDescriptionFramework)


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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:

<Robbery rdf:ID="report-2003-10-23-xyz"> <description>...</description> <suspect> <Thief rdf:about="http://www.ministryOfInterior.gov/criminals#John_Smith"/> </suspect>

</Robbery>


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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:

<Speeding rdf:ID="report-2003-10-23-abc"> <description>...</description> <driver> <Speeder rdf:about="http://www.ministryOfInterior/criminals#John_Doe"/> </driver>

</Speeding>


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OWL Classes

Ministry of Interior has defined ontologies for their information in OWL

For example: Crimes

Robbery Speeding Terrorism

<owl:Class rdf:ID=“Crimes"> </owl:Class>

<owl:Class rdf:ID=“Robbery"> <rdfs:subClassOf rdf:resource="#Crimes"/></owl:Class>

<owl:Class rdf:ID=“Terrorism"> <rdfs:subClassOf rdf:resource="#Crimes"/></owl:Class>

…


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OWL Classes

Ministry of Interior has also defined the following classes

For example: Criminals

Thief Speeders Terrorists

<owl:Class rdf:ID=“Criminals"> </owl:Class>

<owl:Class rdf:ID=“Thief"> <rdfs:subClassOf rdf:resource="#Criminals"/></owl:Class>

<owl:Class rdf:ID=“Terrorists"> <rdfs:subClassOf rdf:resource="#Criminals"/></owl:Class>

…


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OWL Properties

<owl:DatatypeProperty rdf:ID=“description"> <rdfs:domain

rdf:resource="#Crime"/> <rdfs:range

rdf:resource=“http://www.w3.org/2001/XMLSchema#Literal"/>

</owl:DatatypeProperty >

<owl:ObjectProperty rdf:ID=“suspect"> <rdfs:domain

rdf:resource="#Robbery"/> <rdfs:range rdf:resource=“#Thief>

</owl:ObjectProperty >

<owl:ObjectProperty rdf:ID=“driver"> <rdfs:domain

rdf:resource="#Speeding"/> <rdfs:range

rdf:resource=“#Speeder"/></owl:ObjectProperty >

suspect

Robbery Thief

Speeding Speederdriver

Crimes Literal

description


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Any Relationship between the Thief and the Speeder?

Ministry of Interior keeps the OWL descriptions of their files:

<Criminals rdf:about=" http://www.ministryOfInterior/criminals#John_Doe ">

<owl:sameAs rdf:resource=" http://www.ministryOfInterior.gov/criminals#John_Smith "/></Criminals>


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How can this be achieved? owl:sameAs property helps!

OWL provides a property (owl:sameAs) for indicating that two resources (e.g., two people) are the same

Thief

Speeder

John Smith

John Doe

owl:sameAs

Inference: The Thief and the Speeder are one and 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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<PONumber> 1234ABCD </PONumber>

Tagging Data in XML

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

An Element


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Why XML?

EDI XML

BGM+220+1234ABCD+9' DTM+137:20030601:102'

LIN+1' PIA+5+9344:EN+1078341ITEM:VP' QTY+21:16:EA' PRI+AAA:95'

LIN+2' …

<PurchaseOrderRequest> <PONumber>1234ABCD </PONumber> <PurchaseOrderDate>20030601</PurchaseOrderDate> <FirstLineItem> <ItemEAN_Identification no=9344 /> <QuantityOrdered> 16 </QuantityOrdered> <UnitPrice> 95 <UnitPrice></FirstLineItem> <SecondLineItem>…


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Giving Meaning and Structure to Data<PurchaseOrderRequest>

<PONumber>1234ABCD </PONumber>

<PurchaseOrderDate>20030601</PurchaseOrderDate>

<LineItem>

<ItemEAN_Identification no=9344 />

<QuantityOrdered> 16 </QuantityOrdered>

<UnitPrice> 95 <UnitPrice>

</LineItem>

<LineItem> … </LineItem>

</PurchaseOrderRequest>

Start TagStart Tag

An Element

An Attribute

Another Element

End Tag

Data


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Giving Structure to Data

PurchaseOrderRequest

PurchaseOrderDatePONumber LineItem

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: <HandHeldDevice> This device</HandHeldDevice>

<MobileDevice> This device</MobileDevice> But if every user creates its own XML definition for

describing his data, it is not possible to achieve interoperability


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MobileDevice

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

HandHeld 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 ParserApplication Code

Initialize Parser

In memory DOM: PerformProcessing

XMLParser

XMLDocument

Begin parsing

Parsing complete

A parser validates and makes the data contained in an XML document availableto the application


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XSLT Processor

XMLDocument

XSL StyleSheet 2

Output from Style

Sheet 1

Output fromStyle

Sheet 2

XSL StyleSheet 1

Parser

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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table.xsl

bar.xsl

art.xsl


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XML vs EDI

XML is an open human-readable, text format

EDI documents are typically in a compressed, machine-only readable form

XML is designed to require one customised mapping per industry grouping, so most companies will be able to work to one format and use XML

EDI traditionally requires customised mapping of each new trading partners document format

XML requires a reliable PC with an Internet connection

EDI typically requires dedicated servers that cost from USD10,000 and up


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XML vs EDI

XML documents are typically sent via the Internet - i.e. a relatively low-cost public network

EDI documents are typically sent via private and relatively expensive value-added networks (VANs)

XML in Internet-based has low ongoing flat-rate costs using existing Internet connections and relatively low-cost Web Servers

EDI can involve high on-going transaction based costs keeping up the connection to the EDI network and keeping the servers up and running


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XML vs EDI

XML appears to have no upper limit in terms of numbers of users

EDI is estimated to be limited to 300,000 companies worldwide and about 20% of their suppliers because of operational costs and complexity

XML is being developed in a world of shared software development populated by many low-cost tools and open source projects.

EDI was traditionally built from the ground up in semi-isolation without being able to share resources with other programs


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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?


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Earliest Days of Web

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

A Web Browserlike Netscape orExplorer

HTML overHTTP

A Web Serverlike Apache Server

Static Document Exchange: No processingon the serveror on the browser!

WEB


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Interaction through Web Forms

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)

A Web Form(HTML)

Submit

Back End

Processing

CommonGatewayInterface

WEB


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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 <Applet> 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


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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


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Web Services

Web Service

Client Application

XML

WEB

ExistingApplication

ExistingApplication

• 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


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Summary: Evolution of Web Interaction

Human to Machine interaction Machine to Machine or Human to Machine Interaction

User at browser interacts with application at Web Server

Client application interacts with Web Service application

Web App sends HTML to browser for human display

Client and Service exchange XML

Protocol is HTTP Protocol may be HTTP or other


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Web services, SOAP, WSDL and UDDI


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What is a Web Service?

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

To put it simply, Web services are applications that interact with each other using Web standards

Web Service

Client Application

XML

WEB


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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


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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

Service Consumer

Service Provider- Web service- Service Description in WSDL

Publish service

Discover service

Invoke service through SOAP


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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

Web Service

Client Application

XML

WEBExistingApplication Existing

Application

Web Service

Client Application

XML

WEBExistingApplication Existing

Application

WSDL and SOAP:Public contract withthe outside world


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WSDL Provides only the Technical Description of the Service!

Web ServiceService Consumer

Web Service Description Language

defines

uses


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WSDL does not describe Web service semantics: Ontologies do!

Web ServiceService Consumer

Web Service Description

defines

Semantic description of the properties of a service

uses


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WSDL Structure

Service

Port(e.g. http://host/svc)

Binding(e.g. SOAP, JMS,

direct call)

Abstract interface

portType

operation(s)

inMesage outMessage

Port

Binding

Where to access it

How to access it

Abstract definition of the service (set of

Operations)

Operation: An Exchange of

Messages between a serviceRequestor and a Service provider


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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


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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 MessageSOAP Payload

SOAP Header

SOAP Body

SOAP Envelope


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SOAP Endpoint Reference

144.122.230.16 80 /ProductCatalog#getPrice

IP Host Address TCP Port No

Object Endpoint ID

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/ProductCatalog#getPrice"


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SOAP Body

<SOAP-ENV:Header /> <SOAP-ENV:Body> <s:getPrice

xmlns:s="http://www.srdc.metu.edu.tr/ProductCatalog"> <product_name xsi:type="xsd:string">Palm

Pilot</product_name> </s:getPrice> </SOAP-ENV:Body>

</SOAP-ENV:Envelope>

Method Name

Input Parameter


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SOAP ResponseHTTP/1.0 200 OKContent-Type: text/xml; charset="utf-8" Content-Length: 400 <SOAP-ENV:Envelope xmlns:SOAP-ENV="

http://schemas.xmlsoap.org/soap/envelope/" SOAP-ENV:encodingStyle="

http://schemas.xmlsoap.org/soap/encoding" xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance" xmlns:xsd="http://www.w3.org/1999/XMLSchema"> <SOAP-ENV:Header /> <SOAP-ENV:Body> <s:getPriceResponse

xmlns:s="http://www.srdc.metu.edu.tr/ProductCatalog"> <product_price xsi:type="xsd:float">2000.</product_price> </s:getPriceResponse> </SOAP-ENV:Body> </SOAP-ENV:Envelope>

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-secure/


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Semantic Support of Web Services in UDDI Registries


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Web Service Model

UDDI Web Service Registry - Web service descriptions

Service Consumer

Service Provider- Web service- Service Description in WSDL

Publish service

Discover service

Invoke service through SOAP


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Registry APIs (SOAP Messages)

Inquiry API Find

find_business find_service find_binding find_tModel

Get Details get_businessDetail get_serviceDetail get_bindingDetail get_tModelDetail

Publishers API Save

save_business save_service save_binding save_tModel

Delete delete_business delete_service delete_binding delete_tModel


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businessEntitybusinessKeynameURLdescriptioncontactsbusinessServicesidentifierBagcategoryBag

PhoneAddressEmail

Contact

businessServiceKeyNameDescriptionBindingTemplates

PhoneAddressEmail

Contact

businessServiceserviceKeytModelKeyNameDescriptionBindingTemplates

keyedReferencetModelKeykeyNamekeyValue




Business Registration

XML document Created by end-user

company (or on their behalf)

Can have multiple service listings

Can have multiple taxonomy listings


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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/)

Country A2 A3 Number

ITALY IT ITA 380

TURKEY TR TUR 792

… … … …


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North American Industry Classification System (NAICS)


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United Nations Standard Products &Services Code® (UNSPSC)


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Remember the Motivating Example

Needs to find all services which

sell …

Desktop With 256 MByte Speed 2 GHertz In Italy Payment method

should be creditcard

Delivery shouldbe within a week

The process should befully automated: no humaninteraction

A CompanyIn Turkey


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If there is such a service, how can we find it through UDDI Registries?

UDDI Registry

MyService(Speed,Memory,Battery_Life, DeliveryTime,Payment_Method, Location)

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

How to find theService in UDDI Registry?


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UNSPSC Codes for Computers (http://eccma.org/unspsc/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


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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?


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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?


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Summary and Conclusions on the semantic support by UDDI registries UDDI provides very limited semantic support

for Web services!


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ebXML: A Brief Overview


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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 Architecture’s 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


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An Overview of Functional Components in ebXML

Repository

ebXML Business Process

Specifications

Business Document

Specification

ebXMLCore

Components

CPP CPPCPA

BusinessService

Interface

BusinessService

Interface

ContextFor

ReferenceTo

BuiltWith

Implement onePartner Role

Implement otherPartner Role


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ebXMLRegistry 3 Register Company

Information

1 Request BusinessDetails

4 Query aboutCompany A

Company A

Company B

5 Download Scenarios and Profiles

2 BuildLocalSystem

6 Agree onBusiness Arrangements

7 Do Business Transactions!

ebXML compliantsystem


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ebXML Summary and Implementation Status Currently ebXML compliant registries are

available, for example, OASIS ebXML Registry Reference Implementation Project (ebxmlrr), http://ebxmlrr.sourceforge.net/


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How to Exploit Web Services Semantics through ebXML?


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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

RegistryPackage ExtrinsicObject Service

AssociationRegistryEntry

ClassificationScheme


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Classifying a Service in ebXML Registries

Computer(Speed, Memory)

Desktop(case type)

Lap Top(Battery life)

Country codesISO 3166

Italy:IT

Turkey:TR

…

WebService(Payment_Method)

BuyServiceSellService

(DeliveryTime)


The service is from Italy selling Lap Tops with parameters to specify payment methods and delivery time and productproperties


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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



(DeliveryTime)



95

An Example



(DeliveryTime)


“MyService”is a “SellService”because itis classified under it

“MyService” inherits the property “DeliveryTime” because it is a subClass of “SellService”


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How to Define a Classification Hierarchy in ebXML?

<rim:ClassificationScheme id = ‘WebService‘ isInternal='true' nodeType='UniqueCode' >

<rim:Name> <rim:LocalizedString value = ‘WebService'/>

</rim:Name> <rim:Description><rim:LocalizedString value = 'This is a

sample WebServicescheme'/> </rim:Description>

<Slot name = ‘paymentMethod' slotType= 'StringList’/>

</rim:ClassificationScheme>



(DeliveryTime)

<rim:ClassificationNode id = ‘SellService‘ parent= ‘WebService'> <rim:Name> <rim:LocalizedString value = ‘SellService' /> </rim:Name> <rim:Description> <rim:LocalizedString value = ''/> </rim:Description>

<Slot name = ‘deliveryTime' slotType= 'StringList’/></rim:ClassificationNode> …


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Relating a Web service Advertised with Service Ontology in ebXML

MyService:Registry Entry

SellService:ClassificationNode

ServiceToIndustryClassification:Classification

classifiedObject classificationNode

Such a classification indicates that MyService is a “SellService”!


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Classifying a Service With Multiple Hierarchies in an ebXML Registry

MyService




SellService:ClassificationNode

Italy:ClassificationNode

Laptop:ClassificationNode

classifiedObject

classifiedObject classifiedObjectclassification Node classification Node

classification Node


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“SubmitObjectRequest” which declares the semantic of “MyService” and relates it with the “Sell” Service<?xml version = '1.0' encoding = 'UTF-8'?><SubmitObjectsRequest >

<rim:LeafRegistryObjectList><Service id="MyService"><Name> <LocalizedString lang="en_US" value =

“MyService"/> </Name><Classification classificationNode=“SellService“

ClassifiedObject= "MyService" /> <Slot name = ‘deliveryTime'>

<ValueList> <Value>1 Week </Value> </ValueList> </Slot>


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An Example “SubmitObjectRequest” (Cont’d)

<ServiceBinding accessURI="http://www.sun.com/ebxmlrr/registry/nameSpaceI

ndexer"><SpecificationLink specificationObject="wsdl">

</SpecificationLink> </ServiceBinding> </Service>

<ExtrinsicObject id="wsdl" mimeType="text/xml"> </ExtrinsicObject></rim:LeafRegistryObjectList>

</SubmitObjectsRequest>


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How do we locate Web services according to their semantics in an ebXML compliant registry?


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A Filter Query Retrieving all the services classified by SellService Node with Delivery Time 1 Week<AdhocQueryRequest > <ResponseOption returnType = "LeafClass" returnComposedObjects = "true" /> <FilterQuery> <ServiceQuery> <ClassifiedByBranch> <ClassificationNodeQuery> <NameBranch> <LocalizedStringFilter> <Clause> <SimpleClause leftArgument = "value"> <StringClause stringPredicate = "Equal">SellService </StringClause> </SimpleClause> </Clause> </LocalizedStringFilter> </NameBranch> </ClassificationNodeQuery> </ClassifiedByBranch>

<SlotBranch> <SlotFilter> <Clause> <SimpleClause leftArgument = "name_"> <StringClause stringPredicate = "Equal"> deliveryTime </StringClause> </SimpleClause> </Clause> </SlotFilter> <SlotValueFilter> <Clause> <SimpleClause leftArgument = "value"> <StringClause stringPredicate = "Contains"> 1 Week </StringClause> </SimpleClause> </Clause> </SlotValueFilter> </SlotBranch>

… </ServiceQuery> </FilterQuery> </AdhocQueryRequest>


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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


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OWL-S


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OWL-S: Defines an Upper Ontology for Web Services in OWL

describedBy:How it works

Service

ServiceGroundingServiceModel

Resource ServiceProfile

Supports:

How to access it

presents: What it does

provides


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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!

asuman dogacechallenges, bologna, october 23, 20031/101 exploiting semantic of web services through...

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