Exploiting Semantics of Web Services in eBusiness Applications

1
Exploiting Semantics of Web Services in
eBusinessApplications

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

2
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

3
Why do we need the semantics of Web services?
4
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

5
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
6
Ontology
7
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

8
Why use an ontology?

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

9
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

10
Ontology Languages and OWL
DAMLDarpa Agent Markup Language
OIL Ontology Inference Layer (European
Commission Project)
DAMLOIL
RDF (Resource Description Framework)
OWL Web Ontology Language (Being Standardized
by W3C)
11
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
12
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
13
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
14
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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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

17
Semantic Support of Web Services in UDDI
Registries
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UDDI Registry APIs

• 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

19
Defining Service Semantics in UDDI Registries

• By using standard taxonomies
• And by putting the corresponding tModel keys in
  the category bags of services

20
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/)
22
North American Industry Classification System
(NAICS)
23
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?

25
Taxonomies Define Only Class/Subclass
Relationship An Example Taxonomy UNSPSC

• UDDI uses
• taxonomies to describe
• the semantic of Web
• services by relating them
• to tModels

• Through taxonomies
• It is not possible to define properties of
  services
• It is not possible to relate service classes
  with one another

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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
Association
RegistryEntry
RegistryPackage
ExtrinsicObject
Service
ClassificationScheme
29
Exploiting semantics
TravelService
Entertainment Service
Accommodation Service
Transportation Service
?
AirTransportation

• 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
BuyATicket
originatingFrom
destinationTo
paymentMethod
?
MyService
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Relating a Web service Advertised with Service
Ontology in ebXML
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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
33
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

34
Some Observations

• The fact is that we do not have industrial
  strength reasoners yet!
• Semantic can also be taken advantage of through
  querying

35
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)

36
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

37
A query template to obtain the properties of a
generic class
DatatypeProperty
ObjectProperty
1
ebXML Query Get Datatype Properties
ebXML Query Get Object Properties
1
2
2
38
An Example Query Retrieving all the Associations
of Type DatatypeProperty for ReserveAClassFligh
tService

• ltAdhocQueryRequest xmlns
• "urnoasisnamestcebxml-regrepqueryxsd2.0"
  xmlnsxsi
• "http//www.w3.org/2001/XMLSchema-instance"
  xsischemaLocation
• "urnoasisnamestcebxml-regrepqueryxsd2.0
  query.xsd"gt
• ltResponseOption returnType "LeafClass"
  returnComposedObjects "true" /gt
• ltFilterQuerygt ltClassificationNodeQuerygt
  ltSourceAssociationBranchgt
  ltAssociationFiltergt ltClausegt
• ltSimpleClause leftArgument
  "associationType"gt
• ltStringClause
  stringPredicate "Equal"gt
  DatatypePropertylt/StringClausegt
• lt/SimpleClausegt
  lt/Clausegt
• lt/AssociationFiltergt
  
• ltClassificationNodeQuerygt
  ltNameBranchgt
• ltLocalizedStringFiltergt ltClausegt
  ltSimpleClause leftArgument "value"gt
• ltStringClause
  stringPredicate "Contains"gt
  ReserveAFlightServicelt/S
  tringClausegt
• lt/SimpleClausegt
  lt/Clausegt lt/LocalizedStringFiltergt lt/NameBranchgt
• lt/ClassificationNodeQuerygt
  lt/SourceAssociationBranchgt lt/ClassificationNodeQue
  rygt lt/FilterQuerygt lt/AdhocQueryRequestgt

39
A query template to find all the advertised
instances of a Web service class
ebXML Query Get Extension of a ClassificationNode
1
2
40
An Example Query Retrieving all the Services
Classified with ReserveAFlightService
ClassificationNode

• ltAdhocQueryRequest
• xmlns "urnoasisnamestcebxml-regrepqueryx
  sd2.0"
• xmlnsxsi "http//www.w3.org/2001/XMLSchema-in
  stance"
• xsischemaLocation "urnoasisnamestcebxml-r
  egrepqueryxsd 2.0 query.xsd"gt
• ltResponseOption returnType "LeafClass"
  returnComposedObjects "true" /gt
• ltFilterQuerygt ltServiceQuerygt
  ltClassifiedByBranchgt
• ltClassificationNodeQuerygt
• ltNameBranchgt
• ltLocalizedStringFiltergt
• ltClausegt
• ltSimpleClause leftArgument
  "value"gt
• ltStringClause stringPredicate
  "Equal"gt ReserveAFlightService
  lt/StringClausegt
• lt/SimpleClausegt lt/Clausegt
  lt/LocalizedStringFiltergt lt/NameBranchgt
• lt/ClassificationNodeQuerygt
  lt/ClassifiedByBranchgt lt/ServiceQuerygt
  lt/FilterQuerygt
• lt/AdhocQueryRequestgt

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ebXML Registry
TravelService
WSDL of MyService1
OWL-S of MyService1
Entertainment Service
Accommodation Service
Transportation Service
AirTransportation
Extrinsic Object
ReserveAFlight
BuyATicket
Extrinsic Object
SpecificationLink
MyService1
A Content Retrieval Query template
ebXML Query Get SpecificationLink Content of a
Service
1
2
ebXML Query Result
WSDL of MyService1
OWL-S of MyService1
42
Retrieving the WSDL Files

• ltGetContentRequest
• xmlns"urnoasisnamestcebxml-regrepque
  ryxsd2.1"
• xmlnsrim"urnoasisnamestcebxml-regrep
  rimxsd2.1"
• xmlnsxsi"http//www.w3.org/2001/XMLSchem
  a-instance"
• xsischemaLocation"urnoasisnamestcebx
  ml-regreprimxsd2.1
• ../schema/rim.xsd urnoasisnamestcebxml
  -regrepqueryxsd2.1
• ../schema/query.xsd"gt
• ltrimObjectRefListgt
• lt--! The unique id of the WSDL
  file in the registry --gt
• ltrimObjectRef
• id"urnuuid7e4397db-916a-4
  90f-bdc7-c9da"/gt
• lt/rimObjectRefListgt
• lt/GetContentRequestgt

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OWL-S
44
OWL-S Defines an Upper Ontology for Web Services
in OWL
describedByHow it works
45
Web services and the Healthcare Domain
46
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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(No Transcript)
48
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

49
Patient Records Problems

• Content too little, too much, or wrong
• Format poor organization of information
• Access, availability, security
• Linkages and integration

50
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

51
EHR Architectures
The nice thing about standards is that there are
so many to choose from. Andrew Tanenbaum,
Introduction to Computer Networks

• 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)

52
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

53
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

54
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

55
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

56
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

57
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 HL7s message based events directly into
  Web services may result in several inefficiencies

58
HL7 and Web Services

• 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

59
HL7 and Web Services

• 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

60
An Example Service FunctionalityOntology
HealthCareServices
PatientAdministration
PatientCare
PatientReferral
Scheduling
ObservationReporting
PatientInfoRequest
CancelPatientReferral
PatientReferralRequest
InsuranceInformation
ClinicalInformation
DemographicData
GetClinicalInformation
serviceQuality
location
61
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

62
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

63
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

64
An example Service Message Ontology
65
Relating the services with the semantic defined
through an ontology - UDDI
Medical Services
PatientCare
PatientReferral
Observation Reporting
GetClinicalInfo
PatientReferralReq
66
Associating semantics to ebXML
HealthCareServices
PatientCare
PatientAdministration
ObservationReporting
PatientInfoRequest
PatientReferralRequest
Standards Conformed
serviceQuality
ebXML ClassificationNodes
ebXMLslots
67
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

68
Overview of IHE IT Infrastructure Integration
Profiles
IHE IT Infrastructure Technical Committee Charles
Parisot, GE Medical Systems Information
Technologies
69
IHE IT Infrastructure5 Integration Profiles
70
An Example Retrieve Information for Display

• 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

71
Retrieve Information for Display

• Transaction Diagram

Display

Information Source

Types ofRequests
72
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/

73
Web Services and the Travel Industry
74
Overall Information Flow in Tourism
Domain
About 1000 companies
4 major GDSs 10 small
Airline Companies
About 100,000 Hotels
Hundreds Of Chains
Olympic, Air France
E-Comm. Site
Two companies
XML
Hotel Chains
Switching Companies
Travel Agency
GDS
Hilton, BW, Utell, E-Rez,
Hotels
Cryptic
Pegasus, Worldres.
Amadeus, Galileo, Sabre, Worldspan
Hilton Ankara, Sofitel Paris ...
Tens of Thousands Of agencies
Rent-a-Car Chains
Hundreds Of Chains
Avis, Hertz,
Rent-a-Car Agencies
75
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

76
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

77
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)

78
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

79
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

80
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

81
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

82
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

83
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

84
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)

85
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

86
Service Functionality Ontology
First Level
TravelWebServices
.........
VehicleServices
RailServices
AirServices
InsuranceServices
HotelServices
AirDetailsServices
..........
.........
..........
AirBookingServices
AirScheduleServices
CheckingAvailabilityServices
RequestAirAvail
ResponseAirAvail
87
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

88
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!