Download Context-Based Mediation - Computer and Information Science - Lecture Slides and more Slides Applications of Computer Sciences in PDF only on Docsity! A Context-Based Mediation Approach to Compose Semantic Web Services Docsity.com Outline • Current Situation • Current Research • Limits of Current Approach • Proposed Solution • Implementation • Conclusions, Future Work Docsity.com Current Research • Other researchers have focused on two aspects • Create / extend semantic languages – OWL-S, WSMF, WSDL-S… • Automated semantic mediators • Neither approach considers context Docsity.com Limits of Current Approach
“DepartureAirportCode 1 ' | Flight Ticket \GarRantalficket) © YO7 77 |
DepartureDate >| Flight Reservation > Car Rental Ticket |
, Web Service DeparturedirportCode | Car Rental > 1 | righ Ticket
DestinationAirportCode DepartureDate 1] web Service Rental 1D number | !
StartDate/StartTime car rental Ticket
EndDate/EndTime |
Type of Car '
Class of Car
DepartureTime 1
DestinationAirportCod:
ReturnDate
ReturnTime
+
t
1
1
1
ReturnDate 1 '
1
1
| 1 Total Price
1
NumberOfPersons
1
1
I
CarID Number |
I
I
y Data Flow FlightCategory
Price
L-----}-____J
NumberOfPersons
Pre —}__y Addition
----------- ee Web Service
i
i
1
Hl
i
FlightNumber \
i
1
i
“1 Data | Web service
'
Fig. 1. Flight-booking and car rental Web servic
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Limits of Current Approach • Flight service – European • Car Rental service – Japanese • Key Data Conflicts – Currency ( Euro vs Yen ) – Scale Format ( 1 vs 1000 ) – Date-Time Format – Value-Added Taxes (VAT, TVA) Docsity.com Context-Based Model • Semantic Object with Contextual Information – Extends descriptive capabilities • Two Parts – Data ( value v of type t ) – Semantic ( concept c with context C ) • Two types: Static and Dynamic Docsity.com Context-Based Model
concept = domain_ns:price ,
value = 5,
type = xsd:double,
Context = [
(ctxt_ns:currency , xsd:string , ‘‘euro’?, [
(ctxt_ns:country , xsd:string , ‘‘France’’, null)
(ctxt_ns:date, ns:date, 15.05.2005, [
etxt_ns:dateformat , xsd:string , ‘‘dd.mm.yyyy’?, null |]
ctxt-ns:scalefactor , int. 1. null
etxt_ns:VATIncluded , xsd:bool, true. [
ctxt_ns:VATRate, float, 19,6, null |
] //end of context
Listing 3. Sample semantic object.
e
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Context-Based Model • Context explicitly defined in new context ontologies • Extension of domain ontologies – adds context to each concept Docsity.com Mediation Architecture • Need to handle conceptual differences dynamically • Utilizes dynamic code generator to create web services “on-the-fly” • Follows a three-step process Docsity.com Mediation Architecture • Contextualization – Analyzes process, identifies data flows • Automatic Mediator WS Generation – Custom web service to fit flow • Update Original Process – Insert custom services into process Docsity.com Mediation Architecture
Step 1
Detect data
heterogeneities
Step 2
Generate mediator
Web services
Step 3
Insert mediator
Web services into
the BPEL code
and execute
Receive
<Invoke>
<assign>
date, time Car Rental
<invoke> Web Service
On
Flight Reservation
flight ticket
Receve
Web Service ’
_
Addition
Web Service
Web Service <inveke>
Generator & Deployer
<invoke>
assign
<invoke>
Car Rental
On
Flight Reservation
'. flight ticket
date time “>.
3 ., Web Service
Addition
* semantic heteragenelty price Web Service
© medlator Web service <invake>
Fig. 5.
Web Service ‘
Data flow with potential oe
Generation of the mediator Web service.
car rental ticket
total price
car rental ticket
total price
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