Service-Oriented Green ICT framework

There are several ways to compose services at the design time. Model-driven Architecture (MDA) is a software architecture framework proposed by the Object Management Group (OMG). MDA consists of a set of standards that assist the system in creation, implementation, evolution and deployment. The key technologies of MDA are Unified Modelling Language (UML), Meta-Object Facility (MOF), XML Meta-Data Interchange (XMI) and Common Warehouse Metamodel (CWM).

MDA emphasized the importance of modeling for the software architecture design.

MDA suggests a three-layered approach. The Computation Independent Model (CIM) describes a system from the computation-independent point of view to address structural aspects of the system. The Platform Independent Model (PIM) defines a system in terms of a technology-neutral virtual machine or a computational abstraction. The Platform Specific Model (PSM) consists of a platform model that captures the technical platform concepts and a model geared towards the implementation technique. The lifecycle of MDA development is shown as Figure 7.

Figure 7 Lifecycle of MDA Development

There are four kinds of models in MDA. During initial phase, the business analyst analyzes the user requirement in CIM. Next, the PIM based on the outcomes derived from the previous phase to define the functionalities, the structure, and the behavior of a system. The PSM focuses more on implementation and execution platform which could be a specific programming language or database.

Context-awareness is an essential aspect for service utilization, especially when frequent interactions take place between users and environments. In this paper, a solution for developing context-aware web services applications is proposed. The methodology includes a model driven approach to separate the web application functionality development from the context adaptation at the development phases (analysis, design, and implementation). In essence, context adaptation takes place on top of the web application business functionality to facilitate system evolution.

SOA framework provides an easy and uniform way for service composition in a controlled environment, and leverages Web service standards with efficient communication mechanisms. Various definitions of SOA have been given by different groups, vendors, and business analysts. W3C defined SOA as: "A set of components which can be invoked, and whose interface descriptions can be published and discovered." CBDI

defined SOA as: "The policies, practices, frameworks that enable application functionality to be provided and consumed as sets of services published at a granularity relevant to the service

consumer that can be invoked, published and discovered, which are abstracted away from the

implementation using a single, standards based form of interface." Gartner defined SOA as:

"Service-oriented architecture is a client/server software design approach in which an application consists of software services and software service consumers (also known as clients or service

requesters). SOA differs from the more general client/server model in its definitive emphasis on

loose coupling between software components, and in its use of separately standing interfaces."

IBM defined SOA as: "A Service-Oriented Architecture is an enterprise-scale IT architecture for linking resources on demand. These resources are represented as business-aligned services which

can participate and be composed in a value-net, enterprise, or line of business to fulfill business

needs. The primary structuring element for SOA applications is a service as opposed to

subsystems, systems, or components."

The service-oriented applications are different from traditional software architecture, as the traditional software is relative static at runtime compared with service-oriented ones. Therefore, a new service-oriented application can be composed at runtime using existing services. In the Green ICT, it not only provides a framework for the software design and deployment, but also offers an analytic way to indentify services. In the SOA approach, a lot of physical and logical entities can be considered as services, for example, infrastructure as a service, platform as a service, software as a service (SaaS), device as a service, data as a service and etc. In order to coordinate these services, a well governance of SOA architecture is needed. IBM proposed a SOA Framework that reviewed from the two type views of service consumer and service provider. The SOA Framework can see Figure 8and Figure 9.

Figure 8 SOA Framework track¹

Figure 9 SOA template Framework ²

These services based on the framework can be organized into grids. Grids are the platform to enable collaboration and aggregation of heterogeneous resources such as high-speed supercomputer, cluster, store repositories, database, and application

1 Armonk, NY, December 16, 2003. Available at:

http://www.ibm.com/developerworks/webservices/library/ws-soa-enterprise2/ (Last accessed on 15.09.2010). Also available at: . http://www.allhands.org.uk/submissions/papers/81.pdf

2 Mamdouh Ibrahim, Gil Long, Service-Oriented Architecture and Enterprise Architecture, Part 1: A framework for understanding how SOA and Enterprise Architecture work together,

http://www.ibm.com/developerworks/webservices/library/ws-soa-enterprise1/

systems owned by multiple organizations or individuals which are connected by networks. Grid system architecture based on Web service concepts and technologies, which include large-scale data management, information transfer, and distributed computing, gains its momentum and becomes a popular trend.

Thus, the OpenGridForum defined necessary standards for grid architecture and explored their practicality to gird based applications and infrastructures in distributed computing. The Open Grid Service Architecture (OSGA) represented an evolutionary grid system architecture based on web service concepts and technologies. The Open Grid Service Infrastructure (OGSI) provided a distributed system framework which can offer the standard factory and registration interface for creating and discovering grid services.

Chaprt 3. A FUZZY TOPSIS METHOD FOR WEB SERVICE