Continuous ASM, and a Pacemaker Sensing Fragment

The ASM framework is extended to include continuously varying quantities as well as conventional discretely changing ones. This opens the door to the more faithful modeling of many scenarios where digital systems have to interact with the continuously varying physical world. Transitions in the extended framework are thus either moded (for discontinuous changing quantities), or pliant (for smoothly changing quantities). Refinement and retrenchment are defined in the extended context. The framework is used to develop a fragment of a simple system for the sensing problem for cardiac pacemakers, in the context of the pacemaker verification challenge.