Optimizing the Performance of Educational Web Services

We describe how web service architectures can provide better performance to applications by offering fine-grained services. We define web service granularity in terms of the amount of data that can be retrieved from a service in a single request on average. This is important because developers cannot predict if students will be using state of the art hardware. Thus, service-oriented architectures (SOA) with fine service granularity can minimize network communication and allow server machines to perform more work for applications. We present the Rashi Intelligent Tutoring System and describe how its architecture has been adapted into a web service with two competing application interfaces. We show how the interface that uses more fine-grained services leads to significant improvements in network message response time, message size, and response size, without a significant change in the number of requests.