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This paper discusses the quality of service (QoS)-aware composition of Web services. The work is based on the assumption that for each task in a workflow a set of alternative Web services with similar functionality is available and that these Web services have different QoS parameters and costs. This leads to the general optimization problem of how to(More)
The detective quantum efficiency (DQE) is widely accepted as the most relevant parameter to characterize the image quality of medical x-ray systems. In this article we describe a solid method to measure the DQE. The strength of the method lies in the fact that it is self-normalizing so measurements at very low spatial frequencies are not needed.(More)
Business users need to analyse changing sets of information to effectively support their working tasks. Due to the complexity of enterprise systems and available tools, especially technically unskilled users face considerable challenges when trying to flexibly retrieve needed data in an ad-hoc manner. As a consequence, available data is limited to(More)
The composition of Web Services to workflows is one of the major challenges in the area of service-oriented computing. To meet the business and user requirements, it is crucial to manage the quality of service (QoS) of Web Service workflows. In our approach, we calculate the execution plan of workflows on the QoS attributes ex ante based on predictions.(More)
Acknowledging the competition in today's global markets demands enterprises to be resilient in order to survive. Therefore product life cycles shorten and new customer segments have to be addressed permanently. Obviously, such environments require flexible information systems, which can be adapted quickly to the enterprises' changing needs, without spending(More)
Companies are operating in a dynamic environment, resulting in a continuous need of adapting used information systems to changing business processes and associated information needs. Viewed from a micro-perspective, business users are managing and executing business processes on a daily basis, but are not able to adapt used software to their individual(More)
Delivering the right information at the right time to the right persons is one of the most important requirements of today's business world. Business users have to deal with changing information needs, but suffer from their inability of adapting the used information systems to support their changing needs. Enterprise Resource Planning (ERP) systems, which(More)