Change patterns: Co-evolving requirements and architecture

Emerging classes of systems are more and more subject to changes in their requirements and environment assumptions. Such changes have a far-reaching impact across several artifacts. This paper argues that patterns of co-evolution (or change patterns) can be observed between ``privileged'' pairs of artifacts, like the requirements specification and the architectural design. The paper introduces change patterns as a precise framework to systematically capture and handle change. The approach is based on model-driven engineering concepts and is accompanied by a tool-supported process. Changing trust assumptions are presented as an example of security-related evolution, and are used to illustrate the approach.nrpages: 24status: publishe