The composition of services is used to implement complex functionality. The quality of service (QoS) is a demanding issue for the management of service compositions. A QoS-aware service selection recommends the services to be composed to account for the quality of a service composition and its execution cost incurred by requests. It is shown that in the presence of sophisticated service charging a cost minimization objective imposes the need for a request- and service composition-comprehensive service selection.This type of selection is called a tactical service selection. Existing tactical service selection models assume a deterministic execution environment. The need to adjust a service composition during the execution of a request to react on uncertain QoS attributes and service failures is neglected. Service reconfiguration approaches are proposed to deal with service failures, uncertain QoS attributes, and their impact on QoS restrictions. The challenge addressed in this paper is to propose a hierarchical service selection that integrates a tactical service selection with a service reconfiguration to satisfy the cost minimization objective and to maintain a successful execution of requests. It is shown that the tactical service selection can be efficiently combined with an existing service reconfiguration method to achieve both runtime-related goals and tactical objectives.

The design of an enterprise architecture (EA) management function for an enterprise is no easy task. Various frameworks exist as well as EA management tools, which promise to deliver guidance for performing EA management. Nevertheless, the approaches presented by them stay either on a level too abstract to provide realization support or are far too generic, neglecting enterprise-specific EA related concerns. In this article, we discuss the architecture framework of The Open Group (TOGAF) and detail on its promising but nevertheless highly generic architecture development method (ADM). This article shows how the generic development steps can be complemented by a pattern based approach to EA management providing guidance for addressing specific EA related concerns with step-by-step methodologies as well as with corresponding viewpoints and information models.