525 research outputs found

    Aspects of Assembly and Cascaded Aspects of Assembly: Logical and Temporal Properties

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    Highly dynamic computing environments, like ubiquitous and pervasive computing environments, require frequent adaptation of applications. This has to be done in a timely fashion, and the adaptation process must be as fast as possible and mastered. Moreover the adaptation process has to ensure a consistent result when finished whereas adaptations to be implemented cannot be anticipated at design time. In this paper we present our mechanism for self-adaptation based on the aspect oriented programming paradigm called Aspect of Assembly (AAs). Using AAs: (1) the adaptations process is fast and its duration is mastered; (2) adaptations' entities are independent of each other thanks to the weaver logical merging mechanism; and (3) the high variability of the software infrastructure can be managed using a mono or multi-cycle weaving approach.Comment: 14 pages, published in International Journal of Computer Science, Volume 8, issue 4, Jul 2011, ISSN 1694-081

    A Framework for Evaluating Model-Driven Self-adaptive Software Systems

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    In the last few years, Model Driven Development (MDD), Component-based Software Development (CBSD), and context-oriented software have become interesting alternatives for the design and construction of self-adaptive software systems. In general, the ultimate goal of these technologies is to be able to reduce development costs and effort, while improving the modularity, flexibility, adaptability, and reliability of software systems. An analysis of these technologies shows them all to include the principle of the separation of concerns, and their further integration is a key factor to obtaining high-quality and self-adaptable software systems. Each technology identifies different concerns and deals with them separately in order to specify the design of the self-adaptive applications, and, at the same time, support software with adaptability and context-awareness. This research studies the development methodologies that employ the principles of model-driven development in building self-adaptive software systems. To this aim, this article proposes an evaluation framework for analysing and evaluating the features of model-driven approaches and their ability to support software with self-adaptability and dependability in highly dynamic contextual environment. Such evaluation framework can facilitate the software developers on selecting a development methodology that suits their software requirements and reduces the development effort of building self-adaptive software systems. This study highlights the major drawbacks of the propped model-driven approaches in the related works, and emphasise on considering the volatile aspects of self-adaptive software in the analysis, design and implementation phases of the development methodologies. In addition, we argue that the development methodologies should leave the selection of modelling languages and modelling tools to the software developers.Comment: model-driven architecture, COP, AOP, component composition, self-adaptive application, context oriented software developmen

    AO-OpenCom: an AO-Middleware architecture supporting flexible dynamic reconfiguration

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    Middleware has emerged as a key technology in the construction of distributed systems. As a consequence, middleware is increasingly required to be highly modular and configurable, to support separation of concerns between services, and, crucially, to support dynamic reconfiguration: i.e. to be capable of being changed while running. Aspect-oriented middleware is a promising technology for the realisation of distributed reconfiguration in distributed systems. In this paper we propose an aspect-oriented middleware platform called AO-OpenCom that builds AO-based reconfiguration on top of a dynamic component approach to middleware system composition. The goal is to support extremely flexible dynamic reconfiguration that can be applied at all levels of the system and uniformly across the distributed environment. We evaluate our platform by the capability in meeting flexible reconfiguration and the impact of these overheads

    A consistency framework for dynamic reconfiguration in AO-middleware architectures

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    Aspect-oriented (AO) middleware is a promising technology for the realisation of dynamic reconfiguration in distributed systems. Similar to other dynamic reconfiguration approaches, AO-middleware based reconfiguration requires that the consistency of the system is maintained across reconfigurations. AO middleware based reconfiguration is an ongoing research topic and several consistency approaches have been proposed. However, most of these approaches tend to be targeted at specific narrow contexts, whereas for heterogeneous distributed systems it is crucial to cover a wide range of operating conditions. In this paper we address this problem by exploring a flexible, framework-based consistency management approach that cover a wide range of operating conditions ensuring distributed dynamic reconfiguration in a consistent manner for AO-middleware architectures

    Context Oriented Software Middleware

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    Our middleware approach, Context-Oriented Software Middleware (COSM), supports context-dependent software with self-adaptability and dependability in a mobile computing environment. The COSM-middleware is a generic and platform-independent adaptation engine, which performs a runtime composition of the software's context-dependent behaviours based on the execution contexts. Our middleware distinguishes between the context-dependent and context-independent functionality of software systems. This enables the COSM-middleware to adapt the application behaviour by composing a set of context-oriented components, that implement the context-dependent functionality of the software. Accordingly, the software dependability is achieved by considering the functionality of the COSM-middleware and the adaptation impact/costs. The COSM-middleware uses a dynamic policy-based engine to evaluate the adaptation outputs and verify the fitness of the adaptation output with the application's objectives, goals and the architecture quality attributes. These capabilities are demonstrated through an empirical evaluation of a case study implementation

    WComp, a Middleware for Ubiquitous Computing

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