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Organizational and managerial theories of modularity applied to the design and production of complex artifacts are used to interpret the rise and success of Free/Open Source Software methodologies and practices in software engineering. Strengths and risks of the adoption of a modular approach in software project management are introduced and are related to the achievements of the GNU/Linux project as a whole, as well as to the outcomes of some of its sub--projects. It is suggested that mindful implementation of the principles of modularity may improve the rate of success of many Free/Open Source software projects. Specific case studies here depicted, as well as indirect observation of common programming practices employed by Free/Open Source developers and users, suggest a possible revision towards an improved theory of modularity that may be extended also to settings di#erent from software production.

The Design Structure Matrix (DSM) methodology and the Net Option Value (NOV) model have been used before to show how aspects can add value to a design. Following with an in-depth analysis of that study, this paper demonstrates how aspects can be beneficial as well as detrimental. The structural transformations involved in aspect modularizations are carefully analyzed in the context of DSMs. This analysis exposes the unique reversion effect on dependencies that aspect modules are known for. To capture that effect within the NOV model, we extend its original set of six modular operators with an additional reversion operator. Using a design case study, its NOV worksheet and NOV experiments’ curves are presented to show a simulation of the evolutionary patterns of modules, including aspect modules. These patterns show how subtle dependencies, or the lack of them, bring down, or up, the value of an existing design. Based on the observations made in this case study, preliminary design guidelines for aspects are formulated.

Abstract. Crosscutting is usually described in terms of scattering and tangling. However, the distinction between these concepts is vague, which could lead to ambiguous statements. Sometimes, precise definitions are required, e.g., for the formal identification of crosscutting concerns. We propose a conceptual framework for formalizing these concepts based on a crosscutting pattern that shows the mapping between elements at two levels, e.g., concerns and representations of concerns. The definitions of the concepts are formalized in terms of linear algebra, and visualized with matrices and matrix operations. In this way, crosscutting can be clearly distinguished from scattering and tangling. The usability of dependency matrices is illustrated in the analysis of crosscutting across several refinement levels, which can be formalized through the cascading of the crosscutting pattern. 1.

We present our experiences using Net Options Value (NOV) as a framework for evaluating options in software design. We start with a brief introduction of the NOV model, provide summaries of analyses- where and how NOV has been applied, and list some of the open issues based on the early works in this area. In particular we present our approach to understand an important parameter of the NOV called the ‘technical potential ’ of a module and outline our further research directions in using NOV. 1.

Features are increments in program functionality and are the building blocks of product lines. Typical implementation of features using Object Oriented techniques commonly crosscuts several classes and interfaces. There exist many techniques that implement crosscuts, of which Aspect Oriented ones distinguish themselves by their support of dynamic crosscuts expressed with advice. Despite being a core tenet of AOP, very little attention has been paid to measuring crosscuts and how they are implemented by different language constructs in particular advice. In this paper we present a semi-formal definition of a set of basic metrics to measure crosscutting in features that use aspects. Our metrics categorize features within a crosscutting spectrum that ranges from heterogeneous to homogeneous according to the relative number and types of crosscuts features implement. This categorization helps assessing the actual use of aspects for feature implementation and provides a quantitative framework to gauge at and analyze the impact of aspects for product line development. We apply our metrics to a nontrivial product line case study implemented using AspectJ and relate our results to the ongoing assessment of aspects vs. collaboration-based designs for feature implementation. 1