Systems and infrastructures are currently being developed to support Web services. The main idea is to encapsulate an organization’s functionality within an appropriate interface and advertise it as Web services. While in some cases Web services may be utilized in an isolated form, it is normal to expect Web services to be integrated as part of workflow processes. The composition of workflow processes that model e-service applications differs from the design of traditional workflows, in terms of the number of tasks (Web services) available to the composition process, in their heterogeneity, and in their autonomy. Therefore, two problems need to be solved: how to efficiently discover Web services – based on functional and operational requirements – and how to facilitate the interoperability of heterogeneous Web services. In this paper, we present a solution within the context of the emerging Semantic Web, that includes use of ontologies to overcome some of the problems. We start by illustrating the steps involved in the composition of a workflow. Two of these steps are the discovery of Web services and their posterior integration into a workflow. To assist designers with those two steps, we have devised an algorithm to simultaneously discover Web services and resolve heterogeneity among their interfaces and the workflow host. Finally, we describe a prototype that has been implemented to illustrate how discovery and interoperability functions are achieved.

Workflow management systems (WfMSs) have been used to support various types of business processes for more than a decade now. In workflows for e-commerce and Web-services applications, suppliers and customers define a binding agreement or contract between the two parties, specifying Quality of Service (QoS) items such as products or services to be delivered, deadlines, quality of products, and cost of services. The management of QoS metrics directly impacts the success of organizations participating in e-commerce. Therefore, when services or products are created or managed using workflows, the underlying workflow system must accept the specifications and be able to estimate, monitor, and control the QoS rendered to customers. In this paper, we present a predictive QoS model that makes it possible to compute the quality of service for workflows automatically based on atomic task QoS attributes. To this end, we present a model that specifies QoS and describe an algorithm and a simulation system in order to compute, analyze and monitor workflow QoS metrics. 1

Workflow management systems (WfMSs) have been used to support various types of business processes for more than a decade now. In ecommerce processes, suppliers and customers define a binding agreement or contract between the two parties, specifying quality of service (QoS) items such as products or services to be delivered, deadlines, quality of products, and cost of service. Management of such QoS directly impacts success of organizations participating in e-commerce. Organizations operating in modem markets require an excellent degree of quality of service management. Products and services must be available to customers with well-defined specifications. A good management of quality leads to the creation of quality products and services, which in mm fulfills customer expectations and achieves customer satisfaction. Therefore, when services or products are created or managed using workflow processes, the underlying WfMS must accept the specification, be able to predict, monitor, and control the QoS rendered to customers. To achieve these objectives the first step is to develop an adequate QoS model for workflow processes and develop methods to compute QoS.

We propose a Service-oriented Middleware (SoM) that provides an upper level of middleware over rapidly emerging Web Services-based middleware to make it easier to develop complex multi-organizational business applications. Our approach primarily builds upon our experience in building distributed workflow management for multi-organizational processes. Effective and efficient Quality of Service (QoS) management is a critical component of SoM allowing it to guarantee the satisfaction and fulfillment of user and application requirements. This paper reviews a QoS model that also supports ability to automatically compute QoS based on QoS specification of component web Services.

Workflow management systems (WfMSs) have been used to support various types of business processes. As organizations adopt new working models, such as e-commerce, new challenges arise for workflow systems. One such challenge is that of quality of service (QoS) management. QoS management includes mechanisms that specify, compute, monitor, and control the quality of service of the products or services to be delivered. A good management of QoS directly impacts the success of organizations participating in e-commerce activities by better fulfilling customer expectations and achieving customer satisfaction. In this paper we present an implementation of a comprehensive QoS model for workflows we have specified earlier. While the implementation is being carried out for the METEOR workflow management system, the ideas presented here can also be applied to other workflow systems. In this work we describe the components that have been changed, or added, and discuss how they interact to enable the specification, computation, and monitoring of QoS.