This work addresses two problems of distributed software development projects: Inconsistencies between related artifacts such as documents and models and inefficient collaboration of distributed project participants. In particular informal communication is reduced and project knowledge gets lost. We claim that a consistent representation, supporting a unified data model for all documents and models including collaboration artifacts, helps to overcome these problems. As all artifacts are represented in one unified model, it is possible to implicitly capture dependency traces, which support consistency of related artifacts. Informal collaboration artifacts, such as comments, and formal discussions for representing rationale, are externalized and also part of the unified data model. We describe an extendable meta-model as a single consistent representation. Based on the meta-model we introduce the RUSE model, which integrates system, collaboration and organizational models. The models are realized in a tool called Sysiphus, which was used in academic and industrial software development projects. Selected projects are used to evaluate the proposed concepts.
