George R. Ribeiro-Justo

An architectural application framework for evolving distributed systems

Abstract In this paper, we present an object-oriented application framework to support the development of evolving distributed systems. The framework combines concepts of the object-oriented paradigm with those of architectural design. The result is a framework which supports extensible and reusable configurations of distributed components. The framework addresses the problem of evolution by allowing the addition, replacement and extension of components of a configuration. Evolution is also possible at run time, where a configuration can change dynamically depending on a particular event. The paper outlines the fundamental aspects of our framework and presents a case study, which illustrates its application.

A graphical toolset for simulation modelling of parallel systems

In this paper, a simulation model for incorporation within a performance-oriented parallel software development environment is presented. This development environment is composed of a graphical design tool, a simulation facility, and a visualisation tool. Simulation allows parallel program performance to be predicted and design alternatives to be compared. The target parallel system models a virtual machine composed of a cluster of workstations interconnected by a local area network. The simulation model architecture is modular and extensible which allows re-configuration of the platform. The model description and the validation experiments which have been conducted to assess the correctness and the accuracy of the model are also presented.

Intelligent Reconfiguration of Dynamic Distributed Components

Naming service and the reconfiguration management systems usually work in a client-server manner where both the selection of components and the reconfiguration are a result of a request. Developing intelligent systems that are capable of monitoring and learning about themselves, and thereby rapidly react to changes in their environment, has become essential to most systems. This paper proposes an extension to FRODICA (Framework for Distributed Configurable Applications), a framework that supports the development of non-functional oriented reconfiguration of distributed systems, using the Complex Organic Distributed Architecture (CODA). CODA applies cybernetic concepts such as self-organisation, self-regulation and viability to derive an intelligent architecture, which can react to failures in achieving its objectives and proactively search for successful patterns of behaviour. The result is a configuration management system, which can use the knowledge of itself to proactively and dynamically drive both the search and the reconfiguration of its components.

Non-functional integration and coordination of distributed component services

The integration of distributed services has been identified as one of the most important challenges of E-business technology. A great deal of progress has been made in the development of methods and techniques for the integration of distributed components but most of the solutions tends to focus on the problem of syntactical and semantical compatibility of the functional services provided or required by the components. Although the non-functional properties of the services are equally important, because of the difficulties in representing and controlling them, they are usually neglected. This paper investigates the problem of non-functional integration and coordination of distributed components and describes a framework that presents a solution to the problem. The framework is based on the idea of defining the non-functional properties of the services at the early stages of the design and incorporating such properties within the architecture of the application so it can ease their management and control at run time.

Modelling Organic Adaptable Service-Oriented Enterprise Architectures

Developing systems that are capable of monitoring and learning about themselves, and thereby rapidly react to changes in their environment, has become essential to any enterprise. The search for solutions to this complex and challenging problem has stimulated both researchers and practitioners. This paper attempts to connect the views of the researchers and practitioners by relating the state-of-the-art approach proposed by the Complex Organic Distributed Architecture (CODA), with Cap Gemini Ernst & Young’s vision of adaptive architecture. CODA applies cybernetic concepts such as self-organisation, self-regulation and viability to derive an intelligent architecture, which can react to failures in achieving its objectives and proactively search for successful patterns of behaviour. The paper presents a model for developing adaptive enterprise systems using CODA, which at the same time satisfies Cap Gemini Ernst & Young’s characteristics for adaptability. The paper also briefly describes how the model can be implemented using current enterprise infrastructures.

An object-oriented organic architecture for next generation intelligent reconfigurable mobile networks

Next generation mobile networks have great potential in providing personalised and efficient quality of service by using re-configurable platforms. The foundation is the concept of software radio where both the mobile terminal and the serving network can be re-configurable. This approach becomes more effective when combined with historic-based prediction strategies that enable the system to learn about application behaviour and predict its resource consumption. We extend that concept by proposing the use of an object-oriented intelligent decision making architecture, which supports general and large-scale applications. The proposed architecture applies the principles of business intelligence and data warehousing, together with the concept of organic viable systems. The architecture is applied to the CAST (configurable radio with advanced software technology) platform.

Accurate performance prediction using visual prototypes

Behavioural and performance analysis is a fundamental problem in the development of parallel (and distributed) programs. To address this problem, models and supporting environments are required to enable designers to build and analyse their programs. The model we put forward in this paper combines graphical and textual representations of the program structure and uses discrete-event simulation for performance and behaviour predictions. A graphical environment supports our model, providing, amongst other features, a graphical editor, a simulation engine and a performance and behaviour visualisation tool. A number of case studies using this environment are also provided for illustration and validation of our model. Prediction errors observed in comparisons of real execution and simulation of case studies have accuracy to within 10%.