You are required to read and agree to the below before accessing a full-text version of an article in the IDE article repository.

The full-text document you are about to access is subject to national and international copyright laws. In most cases (but not necessarily all) the consequence is that personal use is allowed given that the copyright owner is duly acknowledged and respected. All other use (typically) require an explicit permission (often in writing) by the copyright owner.

For the reports in this repository we specifically note that

  • the use of articles under IEEE copyright is governed by the IEEE copyright policy (available at
  • the use of articles under ACM copyright is governed by the ACM copyright policy (available at
  • technical reports and other articles issued by M‰lardalen University is free for personal use. For other use, the explicit consent of the authors is required
  • in other cases, please contact the copyright owner for detailed information

By accepting I agree to acknowledge and respect the rights of the copyright owner of the document I am about to access.

If you are in doubt, feel free to contact

Software Architecture Evolution and Software Evolvability


Publication Type:

Licentiate Thesis


Mälardalen University


Software is characterized by inevitable changes and increasing complexity, which in turn may lead to huge costs unless rigorously taking into account change accommodations. This is in particular true for long-lived systems. For such systems, there is a need to address evolvability explicitly during the entire lifecycle, carry out software evolution efficiently and reliably, and prolong the productive lifetime of the software systems. In this thesis, we study evolution of software architecture and investigate ways to support this evolution. The central theme of the thesis is how to analyze software evolvability, i.e. a system’s ability to easily accommodate changes. We focus on several particular aspects: (i) what software characteristics are necessary to constitute an evolvable software system; (ii) how to assess evolvability in a systematic manner; (iii) what impacts need to be considered given a certain change stimulus that results in potential requirements the software architecture needs to adapt to, e.g. ever-changing business requirements and advances of technology. To improve the capability in being able to on forehand understand and analyze systematically the impact of a change stimulus, we introduce a software evolvability model, in which subcharacteristics of software evolvability and corresponding measuring attributes are identified. In addition, a further study of one particular measuring attribute, i.e. modularity, is performed through a dependency analysis case study. We introduce a method for analyzing software evolvability at the architecture level. This is to ensure that the implications of the potential improvement strategies and evolution path of the software architecture are analyzed with respect to the evolvability subcharacteristics. This method is proposed and piloted in an industrial setting. The fact that change stimuli come from both technical and business perspectives spawns two aspects that we also look into in this research, i.e. to respectively investigate the impacts of technology-type and business-type of change stimuli.


author = {Hongyu Pei-Breivold},
title = {Software Architecture Evolution and Software Evolvability},
month = {January},
year = {2009},
publisher = {M{\"a}lardalen University},
url = {}