In order to provide better alignment between conceptual requirements and aspect-oriented implementations, specification methods should enable the encapsulation of
of systems. In this paper we argue that
, consisting of such behavioral abstractions, can provide better separation of concerns than conventional architectures, while supporting incremental development for more common units of modularity such as classes. We base our arguments on our experiences with the DisCo method, where behavioral abstractions are composed using the
principle, a technique closely associated with aspect orientation. Moreover, we demonstrate how the alignment between an abstract, horizontally architected specification (or model) and its aspect-oriented implementation can be achieved. Mappings are discussed that implement symmetric DisCo specifications both in Hyper/J, which enables symmetric separation of concerns, and in AspectJ that uses asymmetric structuring.