ucture from an abstract connector model; Kapova [14] introduced variability in the model transformation process (rather than just in the model instances). The fourth line of research is based on Aspect Oriented Modeling (AOM). Alhaj et al. [15] proposed an approach to transform platform independent-model to platform-dependent model in the context of a model transformation chain that generates queueing-based performance models from UML design models of serviceoriented applications. The Reusable Aspect Model (RAM) proposed by Keinzle et al. [16] can be used to model middleware variability of functional requirements, whereas this research aims to model the variability of non-functional requirements for performance prediction. The present work is different in two important ways from its predecessors. First, it considers pure performance model completions, not completions as components as in the first and third research lines. A model completion is both more general and simpler than a compo...