Model-driven engineering (MDE) addresses platform complexity issues by abstracting platformindependent models for subsequent transformation to platform-specific models. This facilitates the design of a single system model and the subsequent generation of multiple model transformations targeted towards specific platforms. However, the increasing complexity of distributed real-time embedded (DRE) systems complicates the development of adequate system models by requiring multiple concerns, some of which may be crosscutting, to be modelled. Separation of concerns, a software engineering technique that decomposes systems into distinct features with minimal overlap, can be used to manage complexity. Aspect-oriented software development (AOSD) is an emerging technique to separate crosscutting concerns in software and has been demonstrated to improve modularity and thereby reduce the complexity of software. In this paper we show how Theme/UML, an aspect-oriented design approach, can be used...