Towards a design-by-contract based approach for realizable connector-centric software architectures

Despite being a widely-used language for specifying software systems, UML remains less than ideal for software architectures. Architecture description languages (ADLs) were developed to provide more comprehensive support. However, so far the application of ADLs in practice has been impeded by at least one of the following problems: (i) advanced formal notations, (ii) lack of support for complex connectors, and (iii) potentially unrealizable designs. In this paper we propose a new ADL that is based on Design-by-Contract (DbC) for specifying software architectures. While DbC promotes a formal and precise way of specifying system behaviours, it is more familiar to practising developers, thus allowing for a more comfortable way of specifying architectures than using process algebras. Furthermore, by granting connectors a first-class status, our ADL allows designers to specify not only simple interaction mechanisms as connectors but also complex interaction protocols. Finally, in order to ensure that architectural designs are always realizable we eliminate potentially unrealizable constructs in connector specifications (the connector “glue”)

Logico-numerical Control for Software Components Reconfiguration

International audienceWe target the problem of the safe control of reconfigurations in component-based software systems, where strategies of adaptation to variations in both their environment and internal resource demands need to be enforced. In this context, the computing system involves software components that are subject to control decisions. We approach this problem under the angle of Discrete Event Systems (DES), involving properties on events observed during the execution (e.g., requests of computing tasks, work overload), and a state space representing different configurations such as activity or assemblies of components. We consider in particular the potential of applying novel logico-numerical control techniques to extend the expressivity of control models and objectives, thereby extending the application of DES in component-based software systems. We elaborate methodological guidelines for the application of logico-numerical control based on a case- study, and validate the result experimentally

An Analysis of a Missing Design Concept for Sustainable Buildings: Addressing the Safety and Health of the Construction Worker

Construction work is inherently dangerous. The 2010 U.S. Bureau of Labor Statistics show the construction industry had the most fatal injuries of all industry sectors, 17%. U.S. regulations place the responsibility for construction safety on the construction contractor. However, owners and designers have the potential to affect the safety of the construction workforce. Owners have gotten more involved in promoting the safety and health of construction workers in recent years; however, studies show that the safety and health of the construction workforce is not typically considered by designers. The Naval Facilities Engineering Command (NAVFAC) - the U.S. Navy\u27s systems command for facility engineering - has initiated several practices to improve construction safety on its projects and has pursued a zero-injury objective for many years, but the efforts focus on the construction contractor. This study\u27s objective was to provide a analysis to present to NAVFAC to consider implementing a program to make construction safety a factor in design decisions. This analysis provides justification, influence factors, and application methods by answering the following questions regarding NAVFAC using the design phase to reduce, or eliminate, construction safety hazards : (1) why, (2) what influences exist, and (3) how will NAVFAC implement? A systematic literature reviewwas used to perform this study. Three reasons were identified to justify NAVFAC to use the design phase to advance this concept: (1) the viability of another approach, (2) design decisions affect construction safety, and (3) a moral obligation exists. The influences identified for designers to consider construction safety were: (1) designers are resistant, (2) owners influence safety, and (3) project delivery methods. Three stages to apply the concept of using the design phase to consider construction safety were discussed: (1) cultural shift, (2) design suggestions and standards, and (3) systematic methods. This study contributes to knowledge by providing a panoramic analysis of the concept to consider the safety of the construction worker. Provided this panoramic analysis, the intended audience of this study, NAVFAC, can decide to further develop an implementation plan to have their designers consider the safety and health of the construction workers