ASPEN: A Stream Processing Environment

In this paper, we describe ASPEN, a concurrent stream processing environment. ASPEN is novel in that it provides a programming model in which programmers use simple annotations to exploit varying degrees and types of concurrency. The degree of concurrency to be exploited is not fixed by the program specification or by the underlying system. Increasing or decreasing the degree of concurrency to be exploited during execution does not require rewriting the entire program, but rather, simply re-annotating it.