Composition, Performance Analysis and Simulation of Web Services

The new paradigm for distributed computing over the Internet is that of Web services. They are Web accessible software components which can be combined and linked together to create new functionality in the form of Web processes. This also creates the need to compose services into processes that are efficient in terms of their performance. In this work, we describe our Service Composition and Execution Tool (SCET) and also describe the various methodologies that could be adopted for evaluating the performance of a Web process. SCET allows for composing services statically using its designer and storing them as Web Service Flow Language (WSFL) based specifications. Executing a process enables one to realize its functionality and also analyze its performance. For executing a process, SCET automatically generates execution code for a composed process. This work also lists techniques such as process execution time analysis and process execution monitoring that can be used to evaluate the performance of individual Web services involved in a process. As processes involving real world services are difficult to be analyzed for their performance, we have used simulation as an alternate technique for analyzing the efficiency of a process. SCET is integrated with the JSIM simulator, enabling users to simulate a process and get statistical performance results that approximate the actual process execution.