Proper decisions play a crucial role in any Software architecture design process. An important decision of design stage is the selection of a suitable Software architecture style. Lack of investigation on the quantitative impact of architecture styles on Software quality attributes is the main problem in using such styles. Consequently, the use of architecture styles in designing is based on the intuition of Software developers. The aim of this research is to quantify the impacts of architecture styles on Software maintainability that is an expected quality of each Software. In this study, architecture styles are quantified based on coupling, complexity and cohesion metrics and ranked by analytic hierarchy process from a maintainability viewpoint. Metrics validation confirms fitness of the metrics. Regarding the great impact of this decision on maintainability of Software product, the presented parametric model provides a basis for sensible selection of architecture style.

Software architecture is known to be an e, ective tool with regards to improving Software quality attributes. Many quality attributes such as maintainability are architecture dependent, and as such, using an appropriate architecture is essential in providing a sound foundation for the development of highly maintainable Software systems. An e, ective way to produce a well-built architecture is to utilize standard architectural patterns. Although the use of a particular architectural pattern cannot have a preserving e, ect on Software maintainability, the mere conformance of a system to any architecture cannot guarantee the system's high maintainability. The use of an inappropriate architecture can seriously undermine Software maintainability at lower levels. In this article, the e, ect of standard architectural patterns on Software maintainability quality attributes is investigated. We develop a quality model for maintainability quality attributes, which is later used to compare various standard architectural patterns. We , nish by investigating two real-world experiences regarding the application of a particular pattern to two di, erent existing architectures, exploring the e, ect of the change in architecture on maintainability quality attributes.

In this paper, after a review on well-known scenario-based methods of SA evaluation, a different approach is introduced to find architectural defects. The proposed method at first, elicits the problems threatening the system's success. Then based on the analysis of the problems and probable defects which could cause the problems, tests are designed and applied to the system in order to find the real defects specially the architectural ones. Results show that the proposed method could be use to find those architectural defects which may be remained covered after applying the other methods. Therefore, it could be used as a mean to SA testing and also as a complementary mechanism along with well-known SA evaluation methods. The proposed method and its components are presented in a systematic form. An illustration of its application on the architecture of a real system is presented and the results are compared with the results of applying ATAM on the same architecture.