asuman dogacride 2004, boston, march 28, 20041/92 exploiting semantics of web services in ebusiness...

Asuman Dogac RIDE 2004, Boston, March 28, 2004

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Exploiting Semantics of Web Services in eBusinessApplicationsAsuman Dogac

Middle East Technical University

06531 Ankara Turkey


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Outline Why do we need the semantics of Web services? Means of expressing semantics: Ontology and Ontology Description

Languages

Semantic Support Available in UDDI Registries

Semantic Support Available in ebXML Registries

Two approaches to exploiting semantics: Querying and Reasoning

Describing the semantics of Web services in two domains Healthcare Tourism Industry


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Why do we need the semantics of Web services?


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Why do we need Web Service Semantics? WSDL only gives the technical specification of the Web services

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 define the

Web service functionality 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

Defining Service Properties Through Ontology Languages


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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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Why use an ontology?

• A common vocabulary

• Ability to define relationships among classes, properties and instances

• Automated Processing

1.Querying

2. Reasoning


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Resource Description Framework (RDF) A W3C recommendation

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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Ontology Languages and OWL

DAML:Darpa Agent Markup Language

OIL: Ontology Inference Layer (European

Commission Project)

DAML+OIL

OWL: Web OntologyLanguage (Being

Standardized by W3C)

RDF (ResourceDescriptionFramework)


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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 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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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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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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Semantic Support of Web Services in UDDI Registries


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UDDI Registry APIs

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




Defining Service Semantics in UDDI Registries

By using standard taxonomies

And by putting the corresponding tModel keys in the category bags of services


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Business categories in UDDI

Three 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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How can we find a service through its semantics in UDDI Registries? Looking for a service to buy a Computer

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: Is this service really selling computers? If so how

about the properties of the product? Payment method? Memory, Speed?


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Taxonomies Define Only Class/Subclass Relationship: An Example Taxonomy: UNSPSC

43.00.00.00.00Communications and ComputerEquipment and Peripherals and

Components and Supplies

43.16.17.00.00Business Transaction and Personal

Business Software

43.16.17.02.00Tax Preparation Software

Through taxonomies: • It is not possible to define properties of services

• It is not possible to relate service classes with one another

• UDDI usestaxonomies to describe the semantic of Webservices by relating them to tModels


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Semantic Support of Web Services in ebXML Registries


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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


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ebXML Registry Information Model (RIM)

RegistryObject

ClassificationNode Classification

RegistryPackage ExtrinsicObject Service

AssociationRegistryEntry

ClassificationScheme


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Exploiting semantics

In relating the semantics with the services advertised in service registries, there are two key issues: Where to store the

generic semantics of the services: In ebXML, metadata is stored in the registry

How to relate the services advertised in the registry with the semantic defined through an ontology: In ebXML through Classification objects

ReserveAFlight

originatingFrom destinationTo paymentMethod

MyService

TravelService

EntertainmentService

AccommodationService

ReserveAFlight BuyATicket

AirTransportation

TransportationService

originatingFrom destinationTo paymentMethod

?

?


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Relating a Web service Advertised with Service Ontology in ebXML

MyService:Registry Entry

ReserveAFlight:ClassificationNode

ServiceToIndustryClassification:Classification

classsifiedObject classificationNode


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How 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

When we associate “MyService” with “ReserveAFlightService”, its meaning becomes clear; that this service is a flight reservation service

Assuming that the “ReserveAFlightService” service has the generic properties such as “originatingFrom”, “destinationTo” and “paymentMethod”, “MyService” also inherits these properties


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Querying vs. Reasoning


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Some Observations Ontologies 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 ontologies


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Some Observations

The fact is that we do not have industrial strength reasoners yet!

Semantic can also be taken advantage of through querying


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Exploiting Semantics through Querying Once semantics is associated with Web services in

ebXML registries, it can be used to discover services simply through queries

Examples: It is possible to find the properties of a Web service class

It is possible to find all the advertised instances of a Web service class in the ontology

It is possible to obtain the content files (WSDL and OWL)


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Querying ebXML Registry through Query Templates This can be achieved through predefined query

templates which yields into automation:

A query template is used to obtain the properties of a generic class

A query template is used for locating service instances of a given generic class node in the class hierarchy

A template is a content retrieval query to obtain the original OWL and WSDL files through the identifiers of the OWL and WSDL files in the SpecificationLinks


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ObjectProperty

DatatypeProperty

TravelService




AirTransportation


originatingFrom destinationTo paymentMethod promotion

ebXML Registry

ebXML QueryGet Datatype Properties

ebXML Query Result

originatingFrom

destinationTo

ebXML QueryGet Object Properties

ebXML Query Result

paymentMethod

promotion

A query template to obtain the properties of a generic class

1

2

1

2


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An Example Query Retrieving all the Associations of Type “DatatypeProperty” for

“ReserveAClassFlightService” <AdhocQueryRequest xmlns ="urn:oasis:names:tc:ebxml-regrep:query:xsd:2.0" xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation ="urn:oasis:names:tc:ebxml-regrep:query:xsd:2.0 query.xsd"> <ResponseOption returnType = "LeafClass" returnComposedObjects = "true" /> <FilterQuery> <ClassificationNodeQuery> <SourceAssociationBranch>

<AssociationFilter> <Clause> <SimpleClause leftArgument = "associationType"> <StringClause stringPredicate = "Equal">

DatatypeProperty</StringClause> </SimpleClause> </Clause> </AssociationFilter> <ClassificationNodeQuery> <NameBranch> <LocalizedStringFilter> <Clause> <SimpleClause leftArgument = "value"> <StringClause stringPredicate = "Contains">

ReserveAFlightService</StringClause> </SimpleClause> </Clause> </LocalizedStringFilter> </NameBranch> </ClassificationNodeQuery> </SourceAssociationBranch>

</ClassificationNodeQuery> </FilterQuery> </AdhocQueryRequest>


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TravelService




AirTransportation


MyService1 MyService2 MyService3

ebXML Registry

ebXML QueryGet Extension of a ClassificationNode

ebXML Query Result

MyService1

MyService2MyService3

A query template to find all the advertised instances of a Web service class

2

1


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An Example Query: Retrieving all the Services Classified with “ReserveAFlightService” ClassificationNode<AdhocQueryRequest xmlns = "urn:oasis:names:tc:ebxml-regrep:query:xsd:2.0" xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation = "urn:oasis:names:tc:ebxml-regrep:query:xsd: 2.0 query.xsd"> <ResponseOption returnType = "LeafClass" returnComposedObjects = "true" /> <FilterQuery> <ServiceQuery> <ClassifiedByBranch> <ClassificationNodeQuery> <NameBranch> <LocalizedStringFilter> <Clause> <SimpleClause leftArgument = "value"> <StringClause stringPredicate = "Equal"> ReserveAFlightService

</StringClause> </SimpleClause> </Clause> </LocalizedStringFilter> </NameBranch> </ClassificationNodeQuery> </ClassifiedByBranch> </ServiceQuery>

</FilterQuery></AdhocQueryRequest>


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ebXML Registry ebXML Repository

WSDL of MyService1

OWL-S of MyService1

TravelService




AirTransportation


MyService1

Extrinsic Object

Extrinsic Object

SpecificationLink

ebXML QueryGet SpecificationLinkContent of a Service

ebXML Query Result

WSDL of MyService1

OWL-S of MyService1

A Content Retrieval Query template

1

2


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Retrieving the WSDL Files

<GetContentRequest xmlns="urn:oasis:names:tc:ebxml-regrep:query:xsd:2.1" xmlns:rim="urn:oasis:names:tc:ebxml-regrep:rim:xsd:2.1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="urn:oasis:names:tc:ebxml-regrep:rim:xsd:2.1 ../schema/rim.xsd urn:oasis:names:tc:ebxml-regrep:query:xsd:2.1 ../schema/query.xsd"> <rim:ObjectRefList> <--! The unique id of the WSDL file in the registry --> <rim:ObjectRef id="urn:uuid:7e4397db-916a-490f-bdc7-c9da"/> </rim:ObjectRefList></GetContentRequest>


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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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Web services and the Healthcare Domain


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Challenges of Healthcare Informatics According to Jonathan Borden, M.D. of ASTM:

A disaster: 1.1 Trillion $/year in the USA 30-40 % overhead Mostly paper based Highly proprietary commercial systems Tens of thousands of people die each year due to poor

information/errors Most of the information is rendered useless


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Challenges of Healthcare Informatics Most of the health information systems today are

proprietary

They often only serve one specific department within a healthcare institute

To complicate the matters worse, a patient's health information may be spread out over a number of different institutes which do not interoperate

This makes it very difficult for clinicians to capture a complete clinical history of a patient


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Patient Records: Problems

Content: too little, too much, or wrong

Format: poor organization of information

Access, availability, security

Linkages and integration


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Challenges of Healthcare Informatics

The systems must interoperate for effectiveness

For interoperability standards are needed

However there are more than one standard in the health care domain


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EHR Architectures

„Candidates“ of EHR architectures: CEN ENV 13606 „EHR Communication“ Good Electronic Health Record (GEHR) OpenEHR CEN EN 13606 (draft) HL7 Clinical Document Architecture HL7 v2 Information Model (implicit) HL7 v3 Reference Information Model (draft)

The nice thing about standards is that there are so many to choose from. Andrew Tanenbaum, Introduction to Computer Networks


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Web Services in the Healthcare Domain

Web services provides the healthcare industry with an ideal platform to achieve the difficult interoperability problems

Web services are designed to wrap and expose existing resources and provide interoperability among diverse applications

It becomes possible to provide the interoperability of medical information systems through standardizing the access to data through WSDL and SOAP rather than standardizing documentation of electronic health records


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Introducing Web services to the healthcare domain brings many advantages

Medical information systems suffer from proliferation of standards to represent the same data; Web services allow for seamless integration of disparate applications representing different and, at times, competing standards

Web services will extend the healthcare enterprises by making their own services available to others

Web services will extend the life of the existing software by exposing previously proprietary functions as Web services


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Semantics of Web Services

In order to exploit Web services to their full potential, it is necessary to describe their semantics

An essential element in defining the semantic of Web services is the domain knowledge

Medicine is one of the few domains to have extensive domain knowledge defined through standards


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Domain Knowledge

Some of the domain knowledge exists in controlled vocabularies, or terminologies: Some vocabularies are rich semantic nets, such as SNOMED-CT

while others such as ICD-10 (International Statistical Classification of Diseases and Related Health Problems) is little more than lexicons of terms

However, there are also standards that expose the business logic in the healthcare domain such as HL7 and Electronic Healthcare Record based standards such as CEN TC251, ISO TC215 and GEHR which define and classify clinical concepts

These standards offer significant value in developing ontologies to express the semantics of Web services


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What kind of Semantics?

Service Functionality Semantics: HL7 has categorized the events in healthcare domain by

considering service functionality which reflects the business logic in this domain

This classification can be used as a basis for defining the service action semantics through a Service Functionality Ontology

Service Message Semantics: Electronic healthcare record (EHR) based standards like HL7

CDA (Clinical Document Architecture), GOM (GEHR Object Model), and CEN TC251's ENV 13606 define meaningful components of EHR so that when transferred, the receiving party can understand the record content better

The meaningful components defined by these standards can be used in developing service message ontologies


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HL7 and Web Services

The primary goal of HL7 is to provide standards for the exchange of data among healthcare computer applications

An event in the healthcare world, called the trigger event, causes exchange of messages between a pair of applications

When an event occurs in an HL7 compliant system, an HL7 message is prepared by collecting the necessary data from the underlying systems and it is passed to the requestor, usually as an EDI message

Mapping HL7’s message based events directly into Web services may result in several inefficiencies


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The input and output messages defined for HL7 events are usually very complex containing innumerous segments of different types and optionality

Furthermore, all the semantics about the business logic and the document structure are hard coded in the message

This implies that, the party invoking the Web service must be HL7 compliant to make any sense of the content of the output parameter(s) returned by the service

Furthermore, the information contained in an HL7 message may be coming from different systems either proprietary or complying to different standards

Hence, in Web services terminology, HL7 events correspond to Composite services, whereas more elementary services are needed


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Since HL7 has already been through an effort of categorizing the events in healthcare domain considering service functionality, it can be used as a basis for a service functionality ontology


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An Example Service FunctionalityOntology HealthCareServices

PatientAdministration PatientCare PatientReferral Scheduling ObservationReporting

PatientInfoRequest CancelPatientReferralPatientReferralRequest

InsuranceInformation ClinicalInformation DemographicData

GetClinicalInformation

serviceQuality location Properties of theGeneric ServiceClass


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Service Messages

A Web service in the healthcare domain usually accesses or updates a part of an electronic healthcare record, that is, parts of the EHR constitute the service parameters

An electronic healthcare record may get very complex with data coming from diverse systems such as lab tests, diagnosis, prescription of drugs which may be in different formats

Electronic healthcare record (EHR) based standards like HL7 CDA, GOM and CEN's ENV 13606 aim to facilitate the interoperability between Medical Information Systems

These standards provide conceptual building blocks or meaningful components

We propose to use these standards as a basis for Service Message Ontology


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GEHR

EHR and Transaction level Navigation level Content (e.g. observation, subjective,

instruction) level Data types (e.g. quantity, multimedia) level Clinical models are expressed outside the

GOM in the form of archetypes


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CEN TC 251 ENV 13606

Folder: High-level subdivisions of the entire EHR for a patient

Composition: A set of record entries relating to one time and place of care delivery; grouped contributions to an aspect of health care activity; composed reports and overviews of clinical progress

Headed Section: Sub-divisions used to group entries with a common theme or derived through a common healthcare process.

Cluster: Low-level aggregations of elementary entries (Record Items) to represent a compound clinical concept


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An example Service Message Ontology

Concept

Property


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UDDI tModels

Relating the services with the semantic defined through an ontology - UDDI

CategoryBag reference

Medical Services

PatientReferralObservation

Reporting

PatientCare

PatientReferralReqGetClinicalInfo

HacettepeHospital

ObservationReportingServices

PatientReferralServices

getClinicalInfo

..

..

..

UDDI Business Entities and Related


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ebXML Classification Hierarchy

Associating semantics to ebXML HealthCareServices

PatientCareObservationReporting

PatientAdministration

PatientInfoRequestPatientReferralRequest

subclassOf subclassOf

subclassOfsubclassOf

serviceQualityStandardsConformed

ebXMLClassificationNodes

ebXML

associationsebXMLslots


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The healthcare informatics industry has already started using Web services An Example: Integrating the Healthcare

Enterprise (IHE)

IHE defines a Web service based implementation framework


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Overview of IHE IT Infrastructure Overview of IHE IT Infrastructure Integration ProfilesIntegration Profiles

IHE IT Infrastructure Technical CommitteeCharles Parisot, GE Medical Systems Information Technologies


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IHE IT Infrastructure5 Integration Profiles

Enterprise User Authentication

Provide users a single nameand

centralized authentication process

across all systems

Enterprise User Authentication

Provide users a single nameand

centralized authentication process

across all systems

Retrieve Information for Display

Access a patient’s clinical information and documents in a

format ready to be presentedto the requesting user


Access a patient’s clinical information and documents in a

format ready to be presentedto the requesting user

Patient Identifier Cross-referencing

for MPI

Map patient identifiers across independent

identification domains

Patient Identifier Cross-referencing

for MPI

Map patient identifiers across independent

identification domains

Synchronize multiple applications on a desktop to the same patient

Patient Synchronized Applications

Synchronize multiple applications on a desktop to the same patient

Patient Synchronized Applications

Consistent Time

Coordinate time across networked

systems

Consistent Time

Coordinate time across networked

systems


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Key Technical Properties: Standards Used:

Web Services (WSDL for HTTP Get). General purpose IT Presentation Formats: XHTML, PDF,

JPEG plus CDA L1. Client may be off-the-shelf browser or display app.

Two services : Retrieve of Specific Information:

Patient centric: patient ID Type of Request Date, Time, nMostRecent

Retrieve a Document Object Unique Instance Identifier (OID) Type of Request Content Type Expected

An Example: Retrieve Information for Display


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Transaction Diagram


Display InformationSource

Retrieve Specific Info for Display [11]

Summary of All ReportsSummary of Laboratory ReportsSummary of Radiology ReportsSummary of Cardiology ReportsSummary of Surgery ReportsSummary of Intensive Care ReportsSummary of Emergency ReportsSummary of Discharge ReportsList of AllergiesList of Medications

Retrieve Document for Display [12]

Persistent Document

Types ofRequests


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For Further Information… IST-1-002103-STP Artemis Project: A

Semantic Web Service-based P2P Infrastructure for the Interoperability of Medical Information Systems

http://www.srdc.metu.edu.tr/artemis/


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Web Services and the Travel Industry


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Overall Information Flow in Tourism Domain

GDS TravelAgency

Avis, Hertz, …

Hilton, BW, Utell, E-Rez, …

Pegasus, Worldres. Amadeus,

Galileo, Sabre, Worldspan …

Olympic, Air France …

Airline Companies

SwitchingCompanies

HotelChains

Rent-a-CarChains

HotelsHilton Ankara, Sofitel Paris ...

Rent-a-CarAgencies

Cryptic

E-Comm.SiteXML

About 100,000Hotels

HundredsOf

ChainsTwo companies

About 1000 companies

Tens ofThousandsOf agencies

4 major GDSs+ 10 small

HundredsOfChains


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Global Distribution Systems (GDS)

Provides connection to the airline, hotel and rent-a-car reservation systems from a single point

Leading GDSs: Amadeus, Sabre, Galileo, Worldspan

Travel Agency – GDS Connectivity Usually in the form of dedicated client terminals that accept

GDS specific cryptic commands, connected to the GDS on a private network

Special APIs provided for Client Application Developers


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Disadvantages of GDSs (I)

But GDSs suffer from:

Mostly they rely on their own private networks They have difficult to use cryptic languages Mainly for human use A request to the system usually involves more than one

interaction with the person on the terminal GDSs have limited speed and search capabilities It is difficult to interoperate them with other systems and

data sources


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Challenges of Travel Industry (II) GDSs are legacy systems and suffer from:

Classical problems with centralized architectures Among the millions of travel agents, only about 10 to 20%

of all travel agents are in connection with the GDS companies

Weak support for SMEs (major hotel chains and etc..) Do not support every type of services

in travel industry (no support for tours)


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A Web service based architecture can bring several advantages to the industry

Opening up the resources over the Internet Interoperability Ability to access legacy systems Better support for SMEs Ease in service discovery Machine processing Better accessibility


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Web Services in Travel Industry A few early adopters in the travel industry have started developing

Web Services

Sabre and Datalex are among

the first companies to develop OTA based Web services

Sabre Web Services provide all the functionality needed to sell travel

Galileo also provides a Web service based solution and claims to have cut down the development time by 80%


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New Business Opportunities through Web Services in the Travel Domain (I) GDS companies support only major travel products;

Airline ticketing, Hotel reservation and Car rental

Through Web services other types of specialized services can be made available

Especially different types of tour and transportation based travel products can be advertised and accessed


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New Business Opportunities through Web Services in the Travel Domain (II) Among the millions of travel agents, only about 10 to

20% of all travel agents are in connection with the GDS companies

Most travel agencies and travel organization companies choose to manage travel services by themselves, due to reasons which may be Technical, or Economical

These companies generally suffer from the lack of advertising their services as well as publishing them electronically


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New Business Opportunities through Web Services in the Travel Domain (III) Web services technology will provide a solution for

all companies, especially for small-to-medium enterprises in the travel industry

The travel agencies and service providers will collaborate with each other on a new level

The companies will be able to provide every type of travel service; the service alternatives will be found on the fly


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Service Semantics in Travel Domain Generic service semantics can be defined through

DAML-S (later OWL-S) upper ontology

However some other properties of the services depend on the application domain

To facilitate the discovery of the Web services, there is a need for an ontology to describe service functionality in the domain


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Ontology Efforts in the Travel Domain

There are some efforts in this direction

There have been some efforts in defining the message ontologies in the travel domain such as the Harmonise project http://www.harmonise.org/

The Harmonise project have defined the Interoperability Minimum Harmonization Ontology (IMHO)


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Open Travel Alliance (OTA)

OTA exposes considerable amount of domain knowledge which can offer significant value in describing the semantics of travel Web services: Generic messages Air messages Car message Hotel messages Golf Tee Times Insurance messages Package Tours/Holiday Bookings Travel Itinerary messages Rail information messages Loyalty messages Profile messages


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Service Functionality Ontology TravelWebServices

HotelServicesVehicleServices RailServices AirServices InsuranceServices

CheckingAvailabilityServices

RequestAirAvail ResponseAirAvail

AirBookingServices

AirScheduleServices

AirDetailsServices

.........

.......... ......... ..........

First Level


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The advantages of Service Functionality Ontology All sorts of Web services can be

classified by using the nodes of such an ontology to make their meaning clear

Web service instance discovery is facilitated: All the services classified through a node in the ontology can be retrieved from service registries


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Message Ontologies

There is a need for message ontologies

It is also necessary to define the semantics of the messages exchanged so that the party receiving the message can interpret it

When ontologies are used to describe the messages, since the messages can refer to ontology concepts, it becomes possible to map one message instance into another through ontology mapping although they may be defined through different ontologies


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For Further Information…

IST-1-002104-STP Satine Project: Semantic-based Interoperability Infrastructure for Integrating Web Service Platforms to Peer-to-Peer Networks

http://www.srdc.metu.edu.tr/satine/


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Conclusions…

Semantic information about Web services can be made use of both through querying the service registries and through reasoners running over ontologies

Needless to say reasoning produces new information and hence is more powerful

But given that we do not have industrial strenth reasoners yet; through querying the we can get very useful semantics on Web services


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Conclusions…

The semantic efforts on the Web services area need to focus on application domains

Semantics is domain specific knowledge

Also different domains have evolved differently; and they have different needs

Web service technology can improve the interoperability and can introduce new business models in these domains


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Thank you for your attention!

asuman dogacride 2004, boston, march 28, 20041/92 exploiting semantics of web services in ebusiness...

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