Component based software engineering promotes the use of software component as a cor- ner stone for new software. Taken from other manufacturing fields, the vision of selecting the components needed and building them as Lego to create a new software seems to of- fer enormous advantages for software development. Worldwide, industry and scholars are trying to remove the obstacles obstructing this course of action. This report names some of the problems that software integrators and developers face. It concentrates on low-level communication and other aspects of integration problems. it is based upon practical and theoretical research. the conclusion of the report is that while each problem can be solved in and of itself, these solutions often lead to the creation of new problems, and therefore leave ample room for further research.

Progress

A software component model is the cornerstone of any Component-based Software Development (CBSD) methodology. Such a model defines the modelling elements for constructing software systems. In software system modelling, it is necessary to capture the three elements of a system's behaviour: (i) control (ii) computation and (iii) data. Within a system, computations are performed according to the flow of control or the flow of data, depending on whether computations are control-driven or data-driven. Computations are function evaluations, assignments, etc., which transform data when invoked by control or data flow. Therefore a component model should be able to model control flow, data flow as well as computations. Current component models all model computations, but beside computations tend to model either control flow only or data flow only, but not both. In this thesis, we present a new component model which can model both control flow and data flow. It contains modelling elements that capture control flow and data flow explicitly. Furthermore, the modelling of control flow is separate from that of data flow; this enables the modelling of both control-driven and data-driven computations. The feasibility of the model is shown by means of an implementation of the model, in the form of a prototype tool. The usefulness of the model is then demonstrated for a specific domain, the embedded systems domain, as well as a generic domain. For the embedded systems domain, unlike current models, our model can be used to construct systems that are both control-driven and data-driven. In a generic domain, our model can be used to construct domain models, by constructing control flows and data flows which together define a domain model.

In current component models, interaction aspects of system behaviour are mostly specified by components, rather than by composition mechanisms, due to the fact that most composition mechanisms cannot express complex interactions. Consequently current component models do not enjoy the benefits that arise from separating the specification of computation from the specification of interaction in software architecture. This thesis investigates the possibility of representing recurring patterns of interaction as composition mechanisms (and other associated component model entities), as distinct from components that define computation; these composition mechanisms would appear as first-class entities in architectures, and can be stored in and reused from repositories. To this end, we have defined a novel, control-driven and data-driven component model that strictly separates computation from interaction. To represent interaction patterns in this model, we have defined composite connectors that can encapsulate control flow and data flow and can be reused via repositories in different contexts. We have also developed a prototype implementation of the component model, and carried out a case study from the reactive control systems domain in order to evaluate the feasibility of our approach. Comparison with related work shows that our composite connectors improve the state of the art in component-based interaction modelling (i) by specifying control flow and data flow explicitly and separately in software architecture; and (ii) by increasing the reuse potential of interaction patterns compared to patterns that are represented by components only.

No description available.

Thesis advisor: Pamela J. Grace / Nurses working in newborn intensive care units (NICU) report experiencing ethical dilemmas related to treatment decisions for infants in their care. The opportunity for nurses to contribute to the formulation of treatment plans for these infants is increasing, but often nurses are required to implement treatment plans with which they may not agree. This causes conflict for the nurse and has been shown to have implications for the nurse and, ultimately, nursing and healthcare practice. Not taking action to resolve the perceived dilemma is especially problematic on several counts (Raines, 1996). Nurse Activism, the outcome variable, is defined as the range of likely actions nurses may take to resolve ethical dilemmas in practice (Penticuff & Walden, 1987). This cross-sectional study investigated the range of likely actions that nurses would take in response to a hypothetical ethical dilemma. The web-based survey was completed by 224 NICU nurses from seven Massachusetts hospitals. Subjects responded to the Nurses Ethical Involvement Survey (Penticuff & Walden, 1987) and demographic questions. Hierarchical multiple regression analysis found that NICU nurses with greater concern for the ethical aspects of clinical practice (p = .001) and an increased perception of their ability to influence ethical decision-making (p = .018) were more likely to exhibit nurse activism to resolve an ethical dilemma and these findings explained just 8.5 percent of the variance. Future research is necessary to determine other factors contributing to, and inhibiting the actions of, nurses to resolve ethical dilemmas encountered in the NICU. / Thesis (PhD) — Boston College, 2010. / Submitted to: Boston College. Connell School of Nursing. / Discipline: Nursing.

L'adaptation en-ligne du logiciel de tolérance aux fautes permet de renforce la sûreté de fonctionnement du système et prenant en compte son environnement. L’adaptation nécessite de nouvelles techniques de conception. Ces travaux visent à comprendre et maîtriser l'impact des modifications du logiciel de tolérance aux fautes en opération sur les fonctionnalités du système, pour en maîtriser les effets de bords. L’approche proposée introduit une architecture réflexive à composants et une modélisation du logiciel. Un modèle structurel du logiciel permet de calculer et appliquer les modifications du contenu du logiciel. Un modèle comportemental décrit les observations attendues en fonctionnement. Il permet de déterminer les états permettant d’appliquer les modifications, d’amener et de maintenir le système dans ces états. Ces travaux montrent que, grâce aux capacités de manipulation et de contrôle en ligne du logiciel, la modification des mécanismes de tolérance aux fautes peut être réalisée en ligne de manière maîtrisée. / On-line fault tolerance adaptation aims at enforcing system dependability by taking into account operational conditions and environment. Adapting the system requires new design techniques. This work aims at understanding and mastering the impact of such software modification in operation, especially regarding side effects on functionalities and dependability properties. Our approach relies on a reflective architecture based on components and models of the software that reflects on the one hand the content of the software in terms of state and algorithms (architectural model) and on the other hand the expected correct behaviour (behavioural model). The first one is used to determine the modifications and apply them at runtime, and the second one is used to drive the system in a state in which modifications can be done consistently, and maintain the system in such a state. We show that; thanks to manipulation capabilities and execution control, we can master the modification of fault tolerance software and ensure correctness properties.

Recent studies indicate that employees distinguish between commitments to interpersonal foci within the organization, such as supervisors and coworkers. Often, these commitments account for variance in outcomes incremental to organizational commitment (e.g., Becker, 1992). Unfortunately, research has tended to focus on affective forms of commitment to foci, while ignoring normative and continuance commitment. To address this gap, the current study proposed and tested models of commitment to foci which incorporate normative and continuance commitment in addition to affective commitment. Results showed some parallels with findings concerning organizational commitment. Much like organizational commitment, support from a focus relates to affective commitment to that focus, while expectations from a focus predict normative commitment to the focus. Additionally, both affective and normative commitment to supervisors and coworkers predicted favorable outcomes, but continuance commitment did not. In line with researchers recommendations (e.g., Johnson, Groff & Taing, in press), interactions among different bases and foci of commitment were also examined. Exploratory analyses suggested a three-way interaction between affective organizational, supervisor, and coworker commitment for predicting in-role performance.

Component-based applications require runtime support to be able to guarantee non-functional properties. This report proposes an architecture for a real-time-capable, component-based runtime environment, which allows to separate non-functional and functional concerns in component-based software development. The architecture is presented with particular focus on three key issues: the conceptual architecture, an approach including implementation issues for splitting the runtime environment into a real-time-capable and a real-time-incapable part, and details of contract negotiation. The latter includes selecting component implementations for instantiantion based on their non-functional properties.

La conception d'applications scientifiques à base de couplage de code est une tâche complexe car elle demande de concilier une facilité de programmation et une obtention de haute performance. En outre, les ressources matérielles (supercalculateurs, grappes de calcul, grilles) permettant leur exécution forment un ensemble hétérogène en constante évolution. Les modèles à base de composants logiciels forment une piste prometteuse pour gérer ces deux sources de complexité car ils permettent d’exprimer les interactions entre les différents constituants d’une application tout en offrant des possibilités d'abstraction des ressources. Néanmoins, les modèles existants ne permettent pas d'exprimer de manière satisfaisante les applications constituées de motifs répliqués dynamiques et hiérarchiques. Ainsi, cette thèse vise à améliorer l'existant – et en particulier la plate-forme générique de simulation numérique SALOME – pour une classe d'applications très répandue : les applications à base de décomposition de domaine et la variante utilisant le raffinement de maillage adaptatif. Tout d'abord, nous avons proposé d’étendre le modèle de composition spatial et temporel de SALOME en ajoutant la possibilité de définir dynamiquement la cardinalité des composants. Cela demande en particulier de gérer les communications de groupes ainsi induites. La proposition a été implémentée dans SALOME et validée via une application de décomposition de domaine à base de couplage de plusieurs instances de Code_Aster. Ensuite, nous avons étudié la pertinence d'utiliser un modèle de composant supportant des connecteurs natifs (MPI, mémoire partagée, appel de méthode) pour permettre une composition plus fine des interactions entre composants. Les résultats d'expériences montrent que des performances équivalentes aux versions natives sont obtenues tout en permettant de manipuler facilement l'architecture de l'application. Enfin, nous avons étudié les extensions nécessaires aux modèles à composants (abstraction,hiérarchie, dynamicité) pour la conception d’applications de raffinement de maillage adaptatif. Les modèles de composants spatio-temporels les plus avancés permettent ainsi d'exprimer ce type d'application mais les performances sont limitées par leur mise en œuvre centralisée ainsi que par le manque de moyens efficaces pour modifier à la volée des assemblages de composants. / Designing scientific applications based on code coupling is a complex task. It requires both an easy programming process and high-performance. In addition, execution resources (supercomputers, computer clusters, grids)  are heterogeneous and constantly evolving. Software components models offer a promising perspective to manage this double complexity because they can express interactions between the different parts of an application while providing abstraction of resources. However, existing models cannot accurately express the applications made of dynamic and hierarchical patterns. The aim of this thesis is to improve the existing models, and in particular the generic platform for numerical simulation SALOME, for a class of widespread applications : applications based on domain decomposition, and its dynamic variant using adaptive mesh refinement. Firstly, we proposed to extend the spatial and temporal composition model provided by SALOME, by adding the ability to dynamically set component cardinality. This requires in particular to manage group communications induced. The proposal has been implemented into SALOME and validated via a domain decomposition application based on coupling several instances of Code_Aster.Then, we have studied the relevance of using a component model supporting native connectors (MPI, shared memory, method invocation), in order to allow finer composition interactions between components.The experiment results show that performances obtained are equivalent to those of the native versions, while allowing to easily manipulate the application architecture. Finally, we studied the necessary component models extensions (abstraction, hierarchy, dynamicity) for designing adaptative mesh refinement applications. The most advanced spatio-temporal component models can express this type of application but performances are limited by their centralized implementation and by the lack of efficient ways of modifying component assembling at execution time.