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Describing Coordination Services with REA
Hans Weigand, Birger Andersson,
Paul Johannesson, Maria Bergholtz,
Jeewanie Jayasinghe Arachchig
Tilburg University
Stockholm University
Assumptions
• Users often need to combine several services to fulfil their goals
• Coordination services are services, possibly implemented as web services, that support the coordination of (real-world) services
• To support users of a future Internet of Services, the effect of the coordination services must be described in such a way that users are not only able to discover services but also to detect and prevent possible conflicts in their composition
Application
users (or service composers addressing a particular user segment) compose mashups and interact with the widgets in them to access web services
users (or service composers addressing a particular user segment) compose mashups and interact with the widgets in them to access web services
The web service typically supports the coordination with a service provider who provides a real-world service as part of a service bundle
The web service typically supports the coordination with a service provider who provides a real-world service as part of a service bundle
The service affects a resource that concerns the user (the resource could be the user himself, for instance in the case of a hotel reservation)
The service affects a resource that concerns the user (the resource could be the user himself, for instance in the case of a hotel reservation)
Research Goal
• A generic language to describe services, the resources they use, as well as planned and actual events. Web services can use this language to represent the pre-conditions and effects of the real services they connect to as well as their own semantics.
• Such a language is to be based on the REA ontology.
Basic REA Ontology
Commitment Pattern (Decrement)
Reserve - Committing to Exchange a Resource
Service Exchange
Service ExchangeThe service is
exchanged between agents in return for
money
The service is exchanged between agents in return for
money
Service Exchange
At the same time, the service is a resource produced in a conversion process at the
provider
At the same time, the service is a resource produced in a conversion process at the
provider
Service Exchange
The service is consumed in a conversion process by the
customer
The service is consumed in a conversion process by the
customer
Service Exchange
The service is used in a conversion process by the
customer
The service is used in a conversion process by the
customer
Coordination Objects
Reservation Purchase order Appointment
Reservations reduce uncertaintyPurchase orders define what to exchangeAppointments are parts of order fulfilments
Coordination Objects
Coordination Objects
A purchase order is a commitment to deliver
products
A purchase order is a commitment to deliver
products
Coordination Objects
A reservation is a conditional commitment to establish a
purchase order
A reservation is a conditional commitment to establish a
purchase order
From Web Services to Business Services