Architectural primitives for distribution and mobility

In this paper, we address the integration of a distribution dimension in an architectural approach to system development and evolution based on the separation between coordination and computation. This third dimension allows us to separate key concerns raised by mobility, thus contributing to our ability to handle the complexity that is inherent to systems required to operate in 'Internet time and space'

A model for capturing the software architecture design process of mobile systems

Numerous efforts have addressed the problem of defining the fundamental architectural building blocks and methods for modelling software architectures in dynamic mobile environments. However, there is a lack of tools for documentingthe evolution of the products generated during the design of software architectures for mobile systems. Based on a generic versioning administration scheme, a model to capture and manage the products of a software architecture design process is proposed placing the focus on mobility concerns. This model follows an operational approach, where design decisions are represented as architectural operations that are captured when they are applied during a design project. The capture of this information enables the tracing of such a design process and its resulting products.Sociedad Argentina de Informática e Investigación Operativ

AMBIENT-PRISMA: Distribution and Mobility in Aspect-Oriented Software Architectures

This thesis presents a framework called Ambient-PRISMA for describing and developing distributed and mobile software systems in an abstract way. Ambient-PRISMA enriches an aspect-oriented software architecture approach called PRISMA with concepts of Ambient Calculus (AC). Ambient Calculus (AC) is a formalism that provides primitives to describe distribution and mobility characteristics in an abstract way. It introduces a concept called ambient which is a bounded place where computation happens. This enrichment is performed by extending the PRISMA metamodel, and Aspect-Oriented Architecture Description Language (AOADL). A case study of an electronic Auction System with mobile agents is used throughout the thesis in order to illustrate the work.Ali Irshaid, N. (2007). AMBIENT-PRISMA: Distribution and Mobility in Aspect-Oriented Software Architectures. http://hdl.handle.net/10251/12900Archivo delegad

Towards certifiable reconfigurable real-time mission critical software systems

This thesis makes a contribution towards the certification of reconfigurable real-time mission critical software systems. In highly reconfigurable software systems it is possible for a situation to arise where the system expends most or all of its resources on reconfiguring, and thus cannot provide sufficient resources to conduct intended computing functions. This anomaly has been termed "configuration thrashing" by the author due to its loose analogy to memory thrashing. If configuration thrashing is not eliminated, or at least minimised, then it is possible for circumstance to occur where reconfigurable systems cannot be certified due to potential failure to meet deadlines caused by configuration thrashing. The elimination of reconfiguration thrashing is a step towards certifiable dynamic reconfigurable systems capable of enforcing deadlines. The elimination of reconfiguration thrashing is necessary, though not sufficient, for this goal. In order to restrict configuration thrashing it is necessary to understand the possibilities available within reconfigurable software. A VDM-SL model is presented to explore the options available for reconfigurable architectures, and has allowed many operators to be formally specified providing a much greater understanding of the tasks involved in reconfiguration. The thesis demonstrates how model checkers can be used to check software processes for configuration thrashing using predefined CSP models, thus allowing system programmers to engineer configuration thrashing out of systems. However, model checkers are susceptible to state space explosion, particularly if models are large and / or complex, which may make the use of the model checkers impractical or even impossible for some systems. The thesis therefore also explores potential run-time solutions to configuration thrashing. These solutions allow developers to include additional logic / processes within their systems in order to eliminate configuration thrashing (without the use of model checkers). Several options are explored in-depth, from providing mechanisms for developers to choose when reconfiguration can / cannot occur, to a rule based solution. The exploration of the rule based solution explores issues such as rule expression, rule predictability, as well as potential core rules. The two approaches taken within this thesis to eliminate, or at least restrict sufficiently, configuration thrashing form a basis which would allow for the certification of reconfigurable real-time mission critical software systems.EThOS - Electronic Theses Online ServiceBAE SystemsGBUnited Kingdo

Investigating communicating sequential processes for Java to support ubiquitous computing

Ubiquitous Computing promises to enrich our everyday lives by enabling the environment to be enhanced via computational elements. These elements are designed to augment and support our lives, thus allowing us to perform our tasks and goals. The main facet of Ubiquitous Computing is that computational devices are embedded in the environment, and interact with users and themselves to provide novel and unique applications. Ubiquitous Computing requires an underlying architecture that helps to promote and control the dynamic properties and structures that the applications require. In this thesis, the Networking package of Communicating Sequential Processes for Java (JCSP) is examined to analyse its suitability as the underlying architecture for Ubiquitous Computing. The reason to use JCSP Networking as a case study is that one of the proposed models for Ubiquitous Computing, the ?-Calculus, has the potential to have its abstractions implemented within JCSP Networking. This thesis examines some of the underlying properties of JCSP Networking and examines them within the context of Ubiquitous Computing. There is also an examination into the possibility of implementing the mobility constructs of the ?-Calculus and similar mobility models within JCSP Networking. It has been found that some of the inherent properties of Java and JCSP Networking do cause limitations, and hence a generalisation of the architecture has been made that should provide greater suitability of the ideas behind JCSP Networking to support Ubiquitous Computing. The generalisation has resulted in the creation of a verified communication protocol that can be applied to any Communicating Process Architecture