Digital object multimodel simulation formalism and architecture

The object-oriented approach known as heterogeneous behavior multimodeling has been developed, used, and reported elsewhere, to facilitate creation, modification, sharing, and reuse of object-oriented models and the simulations created from those models. The digital object extends multimodeling so that digital objects can be shared and combined in ways that ordinary multimodels cannot. We describe an abstract base multimodel and several derived instantiated multimodel types. We also describe a transformation which takes a digital object to a simulation program. We give formal definitions of multimodeling, digital object, and the transformation, then from these definitions prove correctness of execution sequencing of simulations created by applying the transformation to digital objects. Closure under coupling of digital objects follows as a corollary, subject to an assumption regarding experimental frame. We then construct an abstract base architecture for manufacture, flow, and persistence of digital objects. From the base architecture we derive and instantiate a suite of architectures, each targeted at a distinct set of requirements: one to operate locally, another with internet protocols, a third with web protocols, and a fourth to allow digital objects to interoperate with other kinds of simulations.