  Complex system design often proceeds in an iterative fashion, starting from a
high-level model and adding detail as the design matures. This process can be
assisted by metamodeling techniques that automate some model manipulations and
check for or eliminate modeling mistakes. Our work focuses on metamodeling
reliability models: we describe generalization and refinement operations for
these models. Generalization relaxes constraints that may be infeasible or
costly to evaluate; refinement adds further detail to produce a model that more
closely describes the desired system. We define these operations in terms of
operations on system constraints. To illustrate the proposed method, we relate
these constraints to a common Markov chain-based reliability modeling
formalism.
