Even though there has been some research on system evolution, there is no well defined vocabulary to indicate deviation of a system from desired goals. Further, there are no objective measures to indicate whether changes incorporated into a system as part of its evolution violates the integrity of the architectural design. Also, little research has been done to categorize the aspects of a software system that is subject to deviation as the system evolves. In this paper we develop a model for tracking software evolution and propose measures that will objectively indicate the extent of deviation or divergence in a software system. We also categorize the different aspects of software, changes to which can significantly impact usability as well as conceptual coherence.

Software Product Lines (SPL), Component Based Software Engineering (CBSE) and Commercial Off The Shelf (COTS) components provide a rich supporting base for creating software architectures. Further, they promise significant improvements in the quality of software configurations that can be composed from pre-built components. Software architectural styles provide a way for achieving a desired coherence for such component-based architectures. This is because the different architectural styles enforce different quality attributes for a system. If the architectural style of an emergent system could be predicted in advance, a System Integrator could make necessary changes to ensure that the quality attributes dictated by the system requirements were satisfied before the actual system was deployed and tested. In this paper we propose a model for predicting architectural styles based on use cases that need to be met by a system configuration. Moreover, our technique can be used to determine stylistic conformance and hence indicate the presence or absence of architectural drift

This paper discusses a representation for the specification of technology components exploiting the separation of domain requirements (i.e. functional, data and timing requirements) from installation requirements (i.e. implementation specific infrastructure requirements). A process is outlined for building a technology component archive and a set of coefficients is introduced to assist designers in identifying "best-fit" candidates.