Currently, computer science is in the next period of abstraction.
A generation ago we learnt to abstract from hardware and currently we learn to abstract from software in terms of SERVICE oriented architectures (SOA).
It is the service that counts for a customer and not the specific software or hardware that is used to implement the service.
In a later stage, we may even talk in terms of problem-oriented architectures (or more positively expressed in terms of problem solving oriented architectures) because SOAs are biased towards the service provider and not towards the customer that has a problem that needs to be solved.
Service-oriented architectures will become quickly the leading software paradigm.
SOAs will not scale without signification mechanization of – service
discovery, service adaptation, negotiation, service composition, service
invocation, and service monitoring; and data and process mediation.
Therefore, machine processable semantics needs to be added to bring SOAs to their full potential.
Development of open standards (languages) and open source architectures and tools that add semantics to service descriptions
Three Layers of SESA
Turns a service-oriented architecture into a domain specific problem-solving environment
Common Services Layer
The execution environment and the supporting infrastructure that maps the problem descriptions generated at the Problem Solving Layer to the services that can solve the problems
Covers the deployment and provisioning of physical resource being responsible for the actual execution of the applications
D. Fensel, M. Kerrigan, and M. Zaremba (eds.). Implementing Semantic Web
Services - The SESA Framework, Springer, 2008. ISBN: 978-3-540-77019-0 (originally from slide slide Three Layers of SESA)
Problem solving layer
This layer turns a service-oriented architecture into a domain specific problem-solving environment.
It represents the transparent interface to the user(s), where all computing resources are turned into or expressed as services
Supports the full set of operations from an e-commerce framework: information negotiation, etc.
Provides clear separation between business/process logic on one hand and the common service layer
Common Services Layer
Provides an adaptive execution environment and the supporting infrastructure that maps the problem descriptions generated at the Problem Solving Layer to the services that can solve the problems.
Existing architectures and standards from Web service and Grid areas (e.g. OGSA, WSRF, WSDL) which operate only at a syntactic level are semantically enriched and integrated into this layer.
Semantically enrichment of SOAs that implement the Common Service Layer capabilities will help to automate: service discovery, service adaptation, negotiation, service composition, etc.
This layer could be implemented using the W technology
Responsible for actual execution of applications.
All tasks that involve resources such as resource discovery, selection and negotiation for advanced or on-the-fly reservation of resources are supported and implemented in this layer.
Covers the deployment and provisioning of physical resource (e.g. computers, data servers, and networks, usually connected into a Grid) and logical resources (e.g. application components or common services).
This layer may relay on two prominent and widely discussed areas that deal with distributed resources in the context of service oriented computing are Ubiquitous Computing and Grid Computing
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