For more and more systems, software has moved from a peripheral to a central role, replacing mechanical parts and hardware and giving the product a competitive edge. Consequences of this trend are an increase in: the size of software systems, the variability in software artifacts, and the importance of software in achieving the system-level properties. Software architecture provides the necessary abstractions for managing the resulting complexity. We here introduce the Third Working IEEFlIFIP Conference on Software Architecture, WICSA3. That it is already the third such conference is in itself a clear indication that software architecture continues to be an important topic in industrial software development and in software engineering research. However, becoming an established field does not mean that software architecture provides less opportunity for innovation and new directions. On the contrary, one can identify a number of interesting trends within software architecture research. The first trend is that the role of the software architecture in all phases of software development is more explicitly recognized. Whereas initially software architecture was primarily associated with the architecture design phase, we now see that the software architecture is treated explicitly during development, product derivation in software product lines, at run-time, and during system evolution. Software architecture as an artifact has been decoupled from a particular lifecycle phase.

The 2009 Symposium on Component-Based Software Engineering (CBSE 2009) was the 12thin a series ofsuccessful eventsthat havegrowninto the main forum for industrial and academic experts to discuss component technology. Component-based software engineering (CBSE) has emerged as the under- ing technology for the assembly of ?exible software systems. In essence, CBSE is about composing computational building blocks to construct larger building blocks that ful?ll client needs. Most software engineers are involved in some form of component-based development. Nonetheless, the implications of CBSE adoption are wide-reaching and its challenges grow in tandem with its uptake, continuing to inspire our scienti?c speculation. Component-based development necessarily involves elements of software - chitecture, modular software design, software veri?cation, testing, con?guration and deployment. This year's submissions represent a cross-section of CBSE - search that touches upon all these aspects. The theoretical foundations of c- ponent speci?cation, composition, analysis, and veri?cation continue to pose research challenges. What exactly constitutes an adequate semantics for c- munication and composition so that bigger things can be built from smaller things? How can formal approaches facilitate predictable assembly through b- ter analysis? We have grouped the proceedings into two sub-themes that deal with these issues: component models and communication and composition. At the same time, the world is changing.

Much of a software architect's life is spent designing software systems to meet a set of quality requirements. General software quality attributes include scalability, security, performance or reliability. Quality attribute requirements are part of an application's non-functional requirements, which capture the many facets of how the functional - quirements of an application are achieved. Understanding, modeling and continually evaluating quality attributes throughout a project lifecycle are all complex engineering tasks whichcontinuetochallengethe softwareengineeringscienti ccommunity. While we search for improved approaches, methods, formalisms and tools that are usable in practice and can scale to large systems, the complexity of the applications that the so- ware industry is challenged to build is ever increasing. Thus, as a research community, there is little opportunity for us to rest on our laurels, as our innovations that address new aspects of system complexity must be deployed and validated. To this end the 5th International Conference on the Quality of Software Archit- tures (QoSA) 2009 focused on architectures for adaptive software systems. Modern software systems must often recon guretheir structure and behavior to respond to c- tinuous changes in requirements and in their execution environment. In these settings, quality models are helpful at an architectural level to guide systematic model-driven software development strategies by evaluating the impact of competing architectural choices.

This book constitutes the thoroughly refereed post-proceedings of the Second International Conference on the Quality of Software Architectures, QoSA 2006, held in Vasteras, Sweden in June 2006, co-located with the 9th International Symposium on Component-Based Software Engineering, CBSE 2006.

The 12 revised full papers presented together with the abstracts of 2 keynote talks and 3 tutorials were carefully reviewed and selected from 30 submissions. The papers are organized in topical sections on architecture evaluation: selecting alternatives, managing and applying architectural knowledge, architectural evaluation: performance prediction, processes for supporting architecture quality, models for architecture evaluation, and architectural evaluation.

For more and more systems, software has moved from a peripheral to a central role, replacing mechanical parts and hardware and giving the product a competitive edge. Consequences of this trend are an increase in: the size of software systems, the variability in software artifacts, and the importance of software in achieving the system-level properties. Software architecture provides the necessary abstractions for managing the resulting complexity. We here introduce the Third Working IEEFlIFIP Conference on Software Architecture, WICSA3. That it is already the third such conference is in itself a clear indication that software architecture continues to be an important topic in industrial software development and in software engineering research. However, becoming an established field does not mean that software architecture provides less opportunity for innovation and new directions. On the contrary, one can identify a number of interesting trends within software architecture research. The first trend is that the role of the software architecture in all phases of software development is more explicitly recognized. Whereas initially software architecture was primarily associated with the architecture design phase, we now see that the software architecture is treated explicitly during development, product derivation in software product lines, at run-time, and during system evolution. Software architecture as an artifact has been decoupled from a particular lifecycle phase.