The latest technological advances, which introduced innovative and more affordable devices, have contributed to boost the practical application of research in the field of ubiquitous computing (ubicomp). For the development of applications in this area, we need an adequate software infrastructure. In order to do so, we have proposed Continuum, an infrastructure based on service-oriented architecture (SOA), making use of framework and middleware, and employing a redefinition of follow-me semantics. In this redefined vision, users can go anywhere carrying the data and application they want, which they can use in a seamlessly integrated fashion with the real world. In this article, we focus on the description of the service-based architecture proposed for Continuum. The proposal widens the Web services standards to support the mobility of services, allowing them to be deployed, copied, or moved. Besides, the abstraction provided enables the adaptation of legacy applications as Continuum pluggable services.

Abstract One of the challenges in Grid computing research is to provide a means to automatically submit, manage, and monitor applications whose main characteristic is to be composed of a large number of tasks. The large number of explicit tasks, generally placed on a centralized job queue, can cause several problems: (1) they can quickly exhaust the memory of the submission machine; (2) they can deteriorate the response time of the submission machine due to these demanding too many open ports to manage remote execution of each of the tasks; (3) they may cause network traffic congestion if all tasks try to transfer input and/or output files across the network at the same time; (4) they make it impossible for the user to follow execution progress without an automatic tool or interface; (5) they may depend on fault‐tolerance mechanisms implemented at application level to ensure that all tasks terminate successfully. In this work we present and validate a novel architectural model, GRAND (Grid Robust ApplicatioN Deployment), whose main objective is to deal with the submission of a large numbers of tasks. Copyright © 2006 John Wiley & Sons, Ltd.

Abstract The concept of pervasiveness provides the future of computing with an attractive perspective. However, software support for physical and logical mobility raises a set of new requirements and challenges for software production, creating demand for new types of applications, the so‐called pervasive applications, which express follow‐me semantics. The core of these challenges is a dynamic operating environment, which originates with the users' movement in different terminals and locations, and determines different execution contexts. For this envision to become a reality, developers must build applications that constantly adapt to a highly dynamic computing environment. Research works in pervasive computing have already addressed important issues, but they do not approach the problem of how to program general‐purpose pervasive systems. Pervasive applications are distributed, mobile, adaptive and consider context as a first‐order concept. To make the developers' task easier, we have introduced the software architecture called ISAM, which provides an integrated environment aimed at building pervasive applications composed of a development environment and an execution middleware. As part of our study within the ISAM project, we have been investigating how context‐awareness can be expressed at the programming language level with a basis on four main abstractions: context, adapters, adaptation commands, and adaptive behavior management policies. This paper introduces such abstractions, and presents some development and management tools anchored on an example application, which is under development. Copyright © 2006 John Wiley & Sons, Ltd.

The ISAM architecture presents a platform to the development and to the execution of pervasive applications. DIMI (Disseminador Multicast de Informacoes - information multicast disseminator) is an information dissemination service designed for the ISAM architecture. DIMI seeks mainly to obtain scalability, avoiding bottlenecks formation while accepting new consumers on a channel. Besides the search for scalability, this service outfits other necessary characteristics of the computational environment proposed by the ISAM architecture, as planned disconnection support and user mobility support.

ISAM is a proposal directed to resource management in heterogeneous networks, supporting physical and logical mobility, dynamic adaptation and the execution of distributed applications based on components. In order to achieve its goals, ISAM uses, as strategy, an integrated environment that: (a) provides a programming paradigm and its execution environment; (b) handles the adaptation process through a multilevel collaborative model, in which both the system and the application contribute. In this paper we discuss the main mechanisms used to implement the ISAM features, and we also present a parallel application that explores some of this features.