an der

Service-oriented architecture (SOA) is gaining more and more momentum in todays software engineering, for its ease of integrating heterogeneous sys-tems. Web services allow for building complex and dynamic systems where single components can be discovered at run-time by means of certain criteria like Quality of Service (QoS) information. QoS-aware service management and composition highly depends on this valuable data, but most of the cur-rently proposed solutions assume that this information is readily available. This master thesis addresses this fundamental issue by providing two meth-ods to monitor the performance of WCF Web services and composite Web services- also called workflows. One is based on Windows Performance Counters (WPC) provided by the Windows Communication Foundation (WCF). These counters provide a highly accurate way to measure QoS data. The retrieved information is aggregated and attached as valuable metadata to the revision datasets which are stored in the VRESCo registry. The sec-ond method monitors Windows Workflow Foundation (WWF) workflows