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