Application Management Services (AMS) Berliner XML Tage 2004 Dr. Wolfgang P. Dostal Presentation subtitle: 20pt Arial Regular, teal R045 | G182 | B179

Application Management Services (AMS)

Berliner XML Tage 2004

Dr. Wolfgang P. Dostal© 2004 IBM Corporation

Service-oriented Architecture powered by Semantics

Vision or IllusionXML

RDF

Web

Ser

vice

s

Sem

antic

Web

© Dr. Kerstin Dostal 2003

WSDL

Application Management Services

Dr. Wolfgang Dostal © 2004 IBM Corporation

Agenda

Service-oriented Architecture

Semantic Web

Semantic Web Services

Summary



Service Oriented Architecture

A SOA consists of a set of business aligned I/T services that support an organization’s business process goals and objectives, …using interface-based service descriptions that decouple the provider and consumer through open standards and protocols. These services can be combined and choreographed to produce composite enterprise scale services that allow dynamic re-configuration of business value-nets and I/T systems.

Acceptance

Reliability

Simplicity

Dis

trib

uti

on

Loo

sely

Cou

pli

ng

Sta

nd

ard

s

Pro

cess

-ori

ente

d

Source: [ST]

Currently Web services are the most popular implementation of SOA

Service-orientedArchitecture



Web Services Standards

Transports (HTTP/S, JMS, SMTP, FTP, etc.)

XML, XML Infoset

SOAPOther protocolsother services

WSDL UDDI WSIL

WS-Coordination

WS-TransactionsWS-Security

WS-ReliableMessaging

WS-Policy

Business Process Execution Language Management

Transport

Messaging& Encoding

Description& Discovery

Quality ofService

Enterprise

SOAP attachmentsSOAP

WSDL UDDI

Human

inte

ract

ion is

nec

essa

ry to

sel

ect a

ppropria

te W

eb s

ervi

ces!



But what we really want is …

To delegate the discovery of an appropriate Web service to a machine (agent).

To described the service so that a wanted service can automated be tied into an existing application.

Quelle: [WA]



Approach on a syntactic level• The meaning of data and services and their relationship with each

other must be evaluated by a human.

No complete automatization

Approach on a semantic level• Agents (intelligent programs) are able to evaluate the meaning of data

and services and their relationship.

Complete automatization is possible

But what we really want …… automated data exchange and service usage



Introduce Semantics to Web Services

WWWURI, HTML, HTTP

Web ServicesSOAP, WSDL, UDDI

Semantic WebRDF, RDFS, OWL

SemanticWeb Services

Syntax Semantics

Interaction

Automation

Source: [DF]



Introduce Semantics Web Services

WWWURI, HTML, HTTP

Web ServicesSOAP, WSDL, UDDI

Semantic WebRDF, RDFS, OWL

SemanticWeb Services

Syntax Semantics

Interaction

Automation

Source: [DF]Think about business semantics and not structural semantics !



An example (donut-depot is close to empty, less than two)

HTML• I can order new donuts from my most favourite bakery around

the corner. Java

• My kitchen can communicate with my most favourite bakery around the corner and order some more donuts in the case the bakery is working with Java.

Web Services• My kitchen can communicate with my most favourite bakery

even if it is working internally with .NET Semantic Web Services

• My kitchen can order new donuts even when my most favourite bakery is not open and the next bakery has only Berliner in its portfolio.

Use thisservice

Deliver aservice

Do ityourself



Agenda


Semantic Web


Summary



Key word search (Alta Vista)•Unsorted hit list

Google as an „applied“ semantic example

X


Search with semantics (Google)• Semantic: {<href=„“/> to side x} means {Side x is important}

• Hit list sorted by importance

3x important F

2x important C, H

1x important D, E, I

0x important A, B, G

A B

C D E

F G H I


Search with semantics (Google)• Semantic: {<href=„“/> to side x} means {Side x is important}

• Hit list sorted by importance

3x important F

2x important C, H

1x important D, E, I

0x important A, B, G

Enhancement of importance • Create side(s) with as much as possible links <href> to the „really important“ side!

5x important G



What is the Semantic Web?

The Semantic Web is an extension of the current web in which information is given well-defined meaning, better enabling computers and people to work in cooperation.”

Tim Berners-Lee, James Hendler, Ora Lassila, “The Semantic Web,” Scientific American, May 2001



What is the Semantic Web?

The Semantic Web will not replace but refine the present web.

The Semantic Web is not a specification more a philosophy!

The W3C creates the normative appointment, which techniques appoint the Semantic Web.

In principle all techniques which support the philosophy are allowed.

The present strategic technologies of the Semantic Web have independently been developed.

The present strategic technologies are:• XML

• URI

• RDF

• Taxonomies/ Ontologies




Universal Resource Identifier - URI -



„typical“ difficulties with identifiers

Same identifier, but different meaning (homologous)• Solution: using namespaces

Different identifiers, but same meaning (equivalent)• Solution : using rules <de:Krapfen> = <us:Donut>

Different identifiers, but similar meaning (synonymous)• Solution : Construction of rule systems

<de:Berliner> is a type of <de:Krapfen> without a <ba:hole>.



Universal Resource Identifier (URI)

URI can fulfill two tasks• Reference to a location that defines the object

• non-ambiguous identifying of an object (name)

URI as a reference to a document that defines the object• E. g. Dublin Core

http://purl.org/dc/elements/1.1/creator defines the object ‘document creator’

URI as a non-ambiguous identifier• E.g. Dublin Core

http://purl.org/dc/elements/1.1/creator identifies an object as a document creator

Don’t say: donutSay: http://en.wikipedia.org/wiki/Donut




Resource Description Framework - RDF -



Resource Description Framework (RDF)

With the help of RDF statements can be made about objects in a standard format.

W3C Recommendation (since 22/02/1999)

RDF constructs statements as triples• subject, predicate, object

• Each element of a triple is identified with a non-ambiguous URI!

RDF statements can be represented as• Textual statement

• Graph

• RDF/XML notation

• N3 format



Representation of RDF-statements

Textual Representation:• Douglas R. Hofstadter created a document .

• Douglas R. Hofstadter created a document with the title „Gödel, Escher, Bach, ein Endloses Geflochtenes Band “.

And this is what a computer (maybe) sees:• http://www.de.wikipedia.org/wiki/Douglas_R._Hofstadter

http://purl.org/dc/elements/1.1/creator http://purl.org/dc/elements/1.1/document

• http://www.de.wikipedia.org/wiki/Douglas_R._Hofstadter http://purl.org/dc/elements/1.1/creator http://purl.org/dc/elements/1.1/document http://purl.org/dc/elements/1.1/title „Gödel, Escher, Bach, ein Endloses Geflochtenes Band “



Statement represented as graph

Douglas R. Hofstadter

a Documentcreated by

Gödel, Escher, Bach, ein Endloses Geflochtenes Band

with the title

Please note: everything is a URI !

Open Source Editor: http://www.w3.org/2001/11/IsaViz



Statements represented as RDF/XML

<?xml version="1.0"?>

<rdf:RDF

xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"

xmlns:dc="http://purl.org/dc/elements/1.1/">

<rdf:Description rdf:about=“http://www.de.wikipedia.org/wiki/Douglas_R._Hofstadter">

<dc:creator>

<rdf:Description rdf:resource="http://purl.org/dc/elements/1.1/document">

<rdf:Description rdf:resource="http://purl.org/dc/elements/1.1/title">

Gödel, Escher, Bach, ein Endloses Geflochtenes Band

</rdf:Description>

</rdf:Description>

</dc:creator>

</rdf:Description>

</rdf:RDF>




Taxonomy and Ontology



Taxonomy and Ontology

Taxonomy• The classification of information entities in the form of a hierarchy,

according to the presumed relationships of the real-world entities that they represent. [MD]

Ontology• An ontology is an engineering product consisting of “a specific

vocabulary used to describe [a part of] reality, plus a set of explicit assumptions regarding the intended meaning of that vocabulary”- in other words, the specification of a conceptualization. [GR],[GU]

Both describe real world objects and their dependencies with the help of symbols.

Question: What is the difference?



Ontology spectrum

Weak semantics

is subclassification

TaxonomySchema

ER

Thesaurus

has narrower meaning than

Extended ER

XML Topic ModelRDF/S

Conceptual Model

is subclass of

UMLDAML+OIL, OWL

Local Domain Theory

is disjoint subclass of with transitivityproperty

First Order LogicModal Logic

Strong semantics

RelationalModel Quelle: [MD]

inheritance

+associations

+rules

+ axioms +derivation rules

Ontology



The Tree of Knowledge Technologies

AI Knowledge Representation

Semantic Technolog

y Language

s

Content Management Languages

Process Knowledge Languages

Software Modeling Languages

Source: [TKT]



The future of ontologies

„By 2005 lightweight ontologies will be part of 75 percent of application integration projects“.

„… Enterprises should begin to develop the needed semantic modeling and information management skills within their integration competence centers.“

Gartner Research Note T-17-5338, 20. August 2002



The Semantic Web Stack

If one doesn’t use the semantics he/she has the standard web

Semantics is only one elementary part of the Semantic Web

The fully enabled Semantic Web requires also security and trust

Source: [IH]



Quiz

Is the following statement correct?• 2 + 4 = 73

1. Case:• In terms of syntax this statement is correct, because this is the mathematical

notation for the addition. 2. Case:

• Following the axioms and rules of standard mathematics this statement is false. The true statement is 2 + 4 = 6.

RDF gives a Syntax to build statements.• subject, predicate, object

RDF is not a system to decide whether a statement is valid!• For this one needs a taxonomy/ ontology.

RDF is used for statements• To identify elements non-ambiguous due to an URI.

• To identify the relationship (predicate) of two elements (subject, object) non-ambiguous.

• Whether a statement is meaningful or true or has a reality reference* is not in the scope of RDF.

* What ever that means;-)



Agenda


Semantic Web


Summary




Prerequisite for the use of semantics in Web Services• Powerful ontologies with non trivial content

• Concepts for the usage of ontologies in Web Services

Emerging Approaches• DAML-S

http://www.daml.org/services/• OWL

http://www.w3.org/2001/sw/WebOnt/• SWWS

Semantic Web-enabled Web Services• WSMF

http://informatik.uibk.ac.at/users/c70385/wese/

• ...



SOAP, WSDL and UDDI today

SOAP• The SOAP message contains no semantic information about the

document (SOAP-Body).

WSDL• A WSDL document contains no semantic information about the service,

data etc..

UDDI• Taxonomies are used to identify service providers and the service.

• At present there is no concept to identify a synonymous provider or service (ontologies).

To select and bind a Web Service a human as discriminator is needed. A service is at present not selectable or interchangeable via automat.




SOAP and Semantics



Embedding RDF in SOAP

Advantage• A non-ambiguous identification of the message elements is possible.

Disadvantage• The size of a SOAP message is continuing increasing.

Example: W3C mailing-list search service• http://www.w3.org/Search/Mail/Public/advanced_search

So far no specification



Embedding RDF in SOAP (example)

SOAP

<env:Envelope> <env:Body> <autor id="Wolfgang Dostal"> <document> <title> Semantic Web-enabled Web

Services.ppt </title> </document> </autor> </env:Envelope></env:Body>

RDF in SOAP

<env:Bodyxmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"xmlns:dc="http://purl.org/dc/elements/1.1/">

<autor> <rdf:Description href="mailto:[email protected]">

<dc:creator> <document><rdf:Description

href="http://purl.org/dc/elements/1.1/document"> <title>

<rdf:Description href="http://purl.org/dc/elements/1.1/title">

Semantic Web-enabled Web Services.ppt </rdf:Description> </title> </rdf:Description> </document>...

abridged extract




WSDL and Semantics



WSDL with Semantics

Target• The service is described so that a wanted service can automated be

tied into an existing application.

Quelle: [WA]



WSDL with Semantics

extract from a WSDL

 <xsd:schema

targetNamespace="http://namespaces.snowboard-info.com"

xmlns:xsd="http://www.w3.org/1999/XMLSchema"> <wsdl:message wsdl:name="GetEndorsingBoarderRequest" rdf:ID="GetEndorsingBoarderRequest">

<wsdl:operation wsdl:name="GetEndorsingBoarder"> <wsdl:input

rdf:resource="es:GetEndorsingBoarderRequest"/>

<wsdl:binding wsdl:name="EndorsementSearchSoapBinding"

wsdl:type="es:GetEndorsingBoarderPortType" rdf:ID="EndorsementSearchSoapBinding">

Semantics

WSDL

Requestor Provider

communicate

agrees agrees

references

targetNamespace defines theservice non-ambiguous

Quelle: [UO]




UDDI and Semantics



UDDI with Semantics

So far taxonomies (keyword search) in a UDDI are used to classify provider and services.

Tying ontologies into a UDDI by the use of the tModel. OWL as the UDDI Taxonomy Language.

Quelle: [WA]



Agenda


Semantic Web


Summary



Instead of an answer some words to think ...

"Semantic differences, remain the primary roadblock to smooth application integration, one which Web Services alone won't overcome. Until someone finds a way for applications to understand each other, the effect of Web Services technology will be fairly limited. When I pass customer data across [the Web] in a certain format using a Web Services interface, the receiving program has to know what that format is. You have to agree on what the business objects look like. And no one has come up with a feasible way to work that out yet -- not Oracle, and not its competitors..."

--- Oracle Chairman and CEO Larry Ellison




Thank You!

[email protected]



Quellen (1/2)

[ST]• An Analysis Memo from The Stencil Group, April 2002, The Laws of Evolution: A Pragmatic Analysis of the

Emerging Web Services Market [MD]

• The Semantic Web: A Guide to the future of XML, Web Services, and KM; Michael C. Daconta, Leo J. Obrst, Kevin T. Smith; Wiley Publishing ISBN 0-471-43257-1

[GR]• Gruber, T. 1993. “A Translation Approach to Portable Ontology Specifications.”; Knowledge Acquisition 5: 199–

220. [GU]

• Guarino, N. ed. 1998. Formal Ontology in Information Systems. Amsterdam: IOS Press. Proceedings of the First International Conference (FOIS ‘98), June 6–8, Trent, Italy.

[WA] • Web Services Architecture

• http://www.w3.org/TR/2003/WD-ws-arch-20030808/

[DF] • Next Web Generation

• D. Fensel; Leopold-Franzens-Universität Innsbruck

[UO] http://www-106.ibm.com/developerworks/library/ws-wsdlrdf/

http://ontoweb.aifb.uni-karlsruhe.de/



Quellen (2/2)

[DoJe1]• W. Dostal, M. Jeckle; Semantik, Odem einer Service- orientierten Architektur; JavaSpektrum

01/2004 [DoJeKr2]

• W. Dostal, M. Jeckle, W. Kriechbaum; Beschreibung von Semantik; JavaSpektrum 02/2004 [DoJeKr3]

• W. Dostal, M. Jeckle, W. Kriechbaum; Vokabulare und Ontologien; JavaSpektrum 03/2004 [DoJeKr4]

• W. Dostal, M. Jeckle, W. Kriechbaum; Web Services, der natürliche Träger von Semantik; JavaSpektrum 04/2004

[DOJeMeZe]• W. Dostal, M. Jeckle, I. Melzer, B. Zengler; Semantic Web; ObjektSpektrum 05/2002

[TKT]• The "Tree of Knowledge Technologies" was created by Ralph Hodgson of TopQuadrant, Inc.

and is available at TopQuadrant's web-site (http://www.topquadrant.com). Jordan Stuart created the drawing of the "Tree of Knowledge" which was obtained from the Elfwood web site at http://elfwood.lysator.liu.se/loth/j/s/jstuart/scan.gif.html

[IH]• Ivan Herman, http://www.w3.org/2003/Talks/0624-BrusselsSW-IH/Overview.html

Documents

Application Management Services (AMS) Berliner XML Tage 2004 Dr. Wolfgang P. Dostal Presentation subtitle: 20pt Arial Regular, teal R045 | G182 | B179