Sodki Chaari

Enhancing web service selection by QoS-based ontology and WS-policy

The Service Oriented Architecture enables the development of flexible large scale-applications in open environments by dynamically combining Web services. Nevertheless, current techniques fail to address the problem of selecting adequate services to meet service consumer needs. Service selection must take into account non-functional parameters especially the Quality of Service (QoS). In this work we propose a Web service selection approach based on QoS attributes. We extend the WS-Policy to represent QoS policies. We apply ontological concepts to WS-policy in order to enable semantic matching. Publishing QoS policies is also examined in this work. We propose to extend the UDDI register to handle QoS-based policies.

CWSC4EC: how to employ context, web service, and community in enterprise collaboration

Web services are becoming an essential support for inter-enterprise collaborative business process. Nevertheless, in spite of the crucial progress in Web service technologies there is some shortage especially in the discovery and selection phase. In fact, Web services are selected based on functional criteria. But, in the case of business process collaboration there is a need to consider more pragmatic criteria such as context parameters. In this work we present a framework for collaboration process creation. It enables Web services selection based on contextual description. For this end, we present a novel categorization for the context suitable to the inter-enterprise collaboration. The context categorization is represented using a flexible and dynamic ontology-based model. In order to enhance Web service selection and to improve the manageability of a high number of Web services, we use the community concept in order to gather specific domain Web services. The presented framework uses abstract templates called Goal templates to insure an abstract description of required web services. Goal templates gather both functional and contextual parameters used to select suitable services.

An authorization and access control model for workflow

A workflow is a coordinated arrangement of related tasks in an automated process, the systematic execution of which, ultimately achieves some goal. Workflow management systems (WFMSs) are becoming very popular and are being used to support many of the day to day workflows in large organizations. Workflow management systems are used for critical and strategic applications. Since, security is an essential and fundamental part of workflows, the workflow management system has to manage and execute the workflows in a secure way. Security, in a workflow context, involves the implementation of access control security mechanisms to ensure that tasks are performed by authorized subjects only. In this paper we propose a workflow authorization model capable of specifying authorization in such a way that subjects gain access to required objects only during the execution of the task. We build our model over the well known RBAC framework, and that in addition extends RBAC by including new rules in order to be adaptable with workflow context.

Towards Service Oriented Enterprise

To fit economical constraints, enterprises are more and more involved in collaborative strategies and require agile organization. To support such agile organizations, an efficient and agile IT system should be set. This can be partially achieved thanks to Service Oriented Architectures (SOA) that are able to implement opened and agile information system. The collaborative model we built on this approach is based first on the services exposed by each potential partner and then on a convenient assembly process used to build a cooperation process, designed as a services composition. This architecture impacts the enterprise own organization, leading to a service oriented enterprise (SOE). After describing the context we present the SOE framework and its components. Then the assembly process is described.