Keynote -- Rethinking the Use of Models in Software Architecture -- Architectural Design Decisions and Influence on Quality -- Design Reasoning Improves Software Design Quality -- A Tool to Visualize Architectural Design Decisions -- Style-Based Model Transformation for Early Extrafunctional Analysis of Distributed Systems -- Architecture and Components / Reasoning about Components -- Carmen: Software Component Model Checker -- MOSES: MOdeling Software and platform architEcture in UML 2 for Simulation-based performance analysis -- Designing the Enterprise Architecture Function -- Quality Prediction of Service Compositions through Probabilistic Model Checking -- Models and Prediction -- Model-Driven Performance Analysis -- Architectural Specification and Static Analyses of Contractual Application Properties -- Integrating Quality-Attribute Reasoning Frameworks in the ArchE Design Assistant -- Architecture Evaluation Processes -- Middleware Architecture Evaluation for Dependable Self-managing Systems -- Comprehensive Architecture Evaluation and Management in Large Software-Systems -- Sharing the Architectural Knowledge of Quantitative Analysis.

This book constitutes the thoroughly refereed post-proceedings of the Fourth International Conference on the Quality of Software Architectures, QoSA 2008, held in Medford, MA, USA, in July 2007, in conjunction with the 10th International ACM SIGSOFT Symposium on Component-Based Software Engineering, CBSE 2007, and the ROSATEA 2007 event, investigating the Role of Software Architecture for Testing and Analysis, forming the federated events on Component-Based Software Engineering and Software Architecture, CompArch 2007. The 13 revised full papers presented together with 1 keynote lecture were carefully reviewed and selected from 42 submissions. The papers are organized in topical sections on architectural design and architectural decisions, tracing architectural decisions, architecture evaluation, architecture evolution, architecting process and architectural knowledge.