|Researchers:||John S. Davis II|
|Advisor:||Edward A. Lee|
The standard denotational semantic approach as developed by Scott and Strachey focuses not on a metric space of signals but a complete partial order (CPO) of signals. Accordingly, the notion of monotonicity and continuity are used to guarantee well-definedness. This denotational approach has been applied to the Kahn dataflow model of computation in particular. Dataflow is a popular modeling paradigm for signal processors and other systems that are amenable to a functional style. A disadvantage of dataflow modeling is that there is no explicit notion of time, a characteristic that is critical for certain applications.
I am considering a hybrid model of computation that blends dataflow with discrete event modeling. I am studying this both within a theoretical framework and as a software implementation. Theoretically I am working towards the relaxation of some of the DE causality constraints given that the modules are monotonic/continuous. The key mathematical tool I am using towards this goal is Matthews' notion of a partial metric space. From an implementation standpoint, I am implementing an "ordered dataflow" domain within the Ptolemy II software environment. Ptolemy II, the Java-based reincarnation of C++ Ptolemy, is a system level modeling tool. A key advantage of an ordered dataflow system as compared to standard discrete event systems is the possibility for concurrent, multi-threaded processing (in the sense of Misra).
Last updated 03/22/99