μ-DSU:A Micro-Language Based Approach to Dynamic Software Updating

Today software systems play a critical role in society’s infrastructures and many are required to provide uninterrupted services in their constantly changing environments. As the problem domain and the operational context of such software changes, the software itself must be updated accordingly. In this paper we propose to support dynamic software updating through language semantic adaptation; this is done through use of micro-languages that confine the effect of the introduced change to specific application features. Micro-languages provide a logical layer over a programming language and associate an application feature with the portion of the programming language used to implement it. Thus, they permit to update the application feature by updating the underlying programming constructs without affecting the behaviour of the other application features. Such a linguistic approach provides the benefit of easy addition/removal of application features (with a special focus on non-functional features) to/from a running application by separating the implementation of the new feature from the original application, allowing for the application to remain unaware of any extensions. The feasibility of this approach is demonstrated with two studies; its benefits and drawbacks are also analysed

Un interpréteur extensible pour le prototypage des langages d'aspects

The value of using different (possibly domain-specific) aspect languages to deal with a variety of crosscutting concerns in the development of complex software systems is well recognized. One should be able to use several of these languages together in a single program. However, on the one hand, developing a new Domain-Specific Aspect Language (DSAL) in order to capture all common programming patterns of the domain takes a lot of time, and on the other hand, the designer of a new language should manage the interactions with the other languages when they are used together. In this thesis, we introduce support for rapid prototyping and composing aspect languages based on interpreters. We start from a base interpreter of a subset of Java and we analyze and present a solution for its modular extension to support AOP based on a common semantics aspect base defined once and for all. The extension, called the aspect interpreter, implements a common aspect mechanism and leaves holes to be defined when developing concrete languages. The power of this approach is that the aspect languages are directly implemented from their operational semantics. This is illustrated by implementing a lightweight version of AspectJ. To apply the same approach and the same architecture to full Java without changing its interpreter (JVM), we reuse AspectJ to perform a first step of static weaving, which we complement by a second step of dynamic weaving, implemented through a thin interpretation layer. This can be seen as an interesting example of reconciling interpreters and compilers. We validate our approach by describing prototypes for AspectJ, EAOP, COOL and a couple of other DSALs and demonstrating the openness of our AspectJ implementation with two extensions, one dealing with dynamic scheduling of aspects and another with alternative pointcut semantics. Different aspect languages implemented with our framework can be easily composed. Moreover, we provide support for customizing this composition.L'intérêt de l'utilisation de différents langages d'aspects pour faire face à une variété de préoccupations transverses dans le développement de systèmes logiciels complexes est reconnu. Il faudrait être capable d'utiliser plusieurs de ces langages dans un seul logiciel donné. Cependant, d'une part la phase de développement d'un nouveau langage dédié capturant tous les patrons de programmation du domaine prend beaucoup de temps et, d'autre part, le concepteur doit gérer les interactions avec les autres langages quand ils sont utilisés simultanément. Dans cette thèse, nous introduisons un support pour le prototypage rapide et la composition des langages d'aspects, basé sur des interpréteurs. Nous partons d'un interpréteur d'un sous-ensemble de Java en étudiant et en définissant son extension modulaire afin de supporter la programmation par aspects en se basant sur une sémantique d'aspects partagée. Dans l'interpréteur d'aspects, nous avons implémenté des mécanismes communs aux langages d'aspects en laissant des trous à définir pour implémenter des langages d'aspects concrets. La puissance de cette approche est de permettre d'implémenter directement les langages à partir de leur sémantique. L'approche est validée par l'implémentation d'une version légère d'AspectJ. Pour appliquer la même approche et la même architecture à Java sans modifier son interpréteur (JVM), nous réutilisons AspectJ pour effectuer une première étape de tissage statique, qui est complétée par une deuxième étape de tissage dynamique, implémentée par une mince couche d'interprétation. C'est un exemple montrant l'intérêt qu'il peut y avoir à concilier interprétation et compilation. Des prototypes pour AspectJ, EAOP, COOL et des langages dédiés simples, valident notre approche. Nous montrons le caractère ouvert de notre implémentation d'AspectJ en décrivant deux extensions: la première permet l'ordonnancement dynamique des aspects, la deuxième propose des sémantiques alternatives pour les points de coupe. Les langages d'aspects implémentés avec notre approche peuvent être facilement composés. En outre, cette composition peut être personnalisée

Carbon Capture and Storage the Clean Development Mechanism : Underlying Regulatory and Risk Management Issues

Owing to the immediate nature of global warming, some countries like those in the EU indicate that up to 30% of their mitigation strategy for 2050 should be CCS technology based. The need to diversify and use different approaches within climate change mitigation mix cannot be overstated; hence technologies that contribute to the overall mitigation strategy must be in tandem as each has a role to play. Contingent on this therefore, is the need to consider different but equally important factors along with the technologies being used, their strategic locations and other resources needed to bring about the climate change mitigation. To this end, it is expedient that the search for the appropriate jurisdictions with adequate regulatory and correct geological profiles should not be undermined by restricting advanced technological climate change mitigation strategies to developed or economically/technologically advanced countries. The spread to include nations hitherto not economically or technologically advanced but have the potential and capacity either in terms of geology, or proximity to carbon emission sources or other viable resources should be encouraged due to the urgency needed to abate climate change effects nationally and globally. Suffice to say, such jurisdictions need to develop the right regulatory and policy frameworks in order to be fit for purpose. The uniqueness of this thesis underscores these observations by research into different risk indicators and strategies such as risk assessment and management, exploring the potential CCS-CDM linkage using regulatory/legal and risk indicators, identifying and analysing the regulatory, legal elements and the geological profiling vis-à-vis analogous operations in the implementation of CCS under CDM Kyoto Protocol in a Non Annex 1 country using Nigeria as a case study country; and finally point to tentative means of linking CCS and CDM