Incorporating cores into system-level specification

We describe an approach for incorporating cores into a system-level specification. The goal is to allow a designer to specify both custom behavior and pre-designed cores at the earliest design stages, and to refine both into implementations in a unified manner. The approach is based on experience with an actual application of a GPS-based navigation system. We use an object oriented language for specification, representing each core as an object. We define three specification levels, and we evaluate the appropriateness of existing inter-object communication methods for cores. The approach forms the specification basis for the Dalton project.