11 research outputs found

    Evaluation of mobile frameworks-conceptual and technological aspects

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    Design and Implementation of S-MARKS: A Secure Middleware for Pervasive Computing Applications

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    As portable devices have become a part of our everyday life, more people are unknowingly participating in a pervasive computing environment. People engage with not a single device for a specific purpose but many devices interacting with each other in the course of ordinary activity. With such prevalence of pervasive technology, the interaction between portable devices needs to be continuous and imperceptible to device users. Pervasive computing requires a small, scalable and robust network which relies heavily on the middleware to resolve communication and security issues. In this paper, we present the design and implementation of S-MARKS which incorporates device validation, resource discovery and a privacy module

    Modelo de métrica multidimensional para a melhoria do roteamento em redes AD HOC móveis

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    Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2013.Este trabalho visa a propor uma métrica multidimensional que tem como propósito causar um melhor desempenho no roteamento de redes ad hoc móveis, na presença de nós egoístas e nós em modo sleep, e com mobilidade. A melhora de desempenho diz respeito, principalmente, ao incremento da taxa de entrega de pacotes com sucesso. Para alcançar um melhor desempenho, foram observados e analisados os resultados prévios alcançados por outras métricas, o que resultou na descoberta de padrões e comportamentos, de modo a embasar à elaboração de uma nova métrica capaz de suprir as lacunas e imprecisões daquelas métricas existentes anteriormente. A validação do trabalho foi feita por método de simulação, tendo o protocolo DSR sido modificado para implantar a métrica proposta e operar considerando tal métrica. Como resultado das simulações, constatou-se que métrica proposta por este trabalho teve, em alguns pontos, uma taxa de entrega de pacotes com sucesso 30% superior àquela encontrada para a métrica original do próprio protocolo DSR (DynamicSourceRouting) e cerca de 15% superior àquela encontrada para uma métrica proposta em trabalho precedente (Serique; Sousa, 2011).This work aims to propose a multidimensional metric that aims to improve routing performance in mobile ad hoc networks in the presence of selfish nodes, nodes in sleep mode. In order to reach a better performance in the delivery rate of packets successfully, we observed the results achieved by other metrics in simulations, which resulted in the discovery of patterns and behaviors that led to the development of a metric that supplied the gaps and inaccuracies of those metrics. This work´s validation was performed using a simulation method, with the DSR (Dynamic Source Routing) protocol which was modified so as to implement and to operate with our proposed metric. The simulations results show that the metric proposed in this work presents, at some points, a successfully delivery rate of packets 30% higher than the original metric of the DSR protocol and about 15% higher than that of the metric proposed in a previous work by (Serique; Sousa, 2011)

    Evolutionary Service Composition and Personalization Ecosystem for Elderly Care

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    Current demographic trends suggest that people are living longer, while the ageing process entails many necessities, calling for care services tailored to the individual senior’s needs and life style. Personalized provision of care services usually involves a number of stakeholders, including relatives, friends, caregivers, professional assistance organizations, enterprises, and other support entities. Traditional Information and Communication Technology based care and assistance services for the elderly have been mainly focused on the development of isolated and generic services, considering a single service provider, and excessively featuring a techno-centric approach. In contrast, advances on collaborative networks for elderly care suggest the integration of services from multiple providers, encouraging collaboration as a way to provide better personalized services. This approach requires a support system to manage the personalization process and allow ranking the {service, provider} pairs. An additional issue is the problem of service evolution, as individual’s care needs are not static over time. Consequently, the care services need to evolve accordingly to keep the elderly’s requirements satisfied. In accordance with these requirements, an Elderly Care Ecosystem (ECE) framework, a Service Composition and Personalization Environment (SCoPE), and a Service Evolution Environment (SEvol) are proposed. The ECE framework provides the context for the personalization and evolution methods. The SCoPE method is based on the match between the customer´s profile and the available {service, provider} pairs to identify suitable services and corresponding providers to attend the needs. SEvol is a method to build an adaptive and evolutionary system based on the MAPE-K methodology supporting the solution evolution to cope with the elderly's new life stages. To demonstrate the feasibility, utility and applicability of SCoPE and SEvol, a number of methods and algorithms are presented, and illustrative scenarios are introduced in which {service, provider} pairs are ranked based on a multidimensional assessment method. Composition strategies are based on customer’s profile and requirements, and the evolutionary solution is determined considering customer’s inputs and evolution plans. For the ECE evaluation process the following steps are adopted: (i) feature selection and software prototype development; (ii) detailing the ECE framework validation based on applicability and utility parameters; (iii) development of a case study illustrating a typical scenario involving an elderly and her care needs; and (iv) performing a survey based on a modified version of the technology acceptance model (TAM), considering three contexts: Technological, Organizational and Collaborative environment

    Adaptations dynamiques au contexte en informatique ambiante : propriétés logiques et temporelles

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    In ubiquitous computing, applications are built as a collaboration of computerized and communicating objects called devices. Because these devices can be mobile or subject to failures, this infrastructure evolves dynamically and unpredictably. Thus, to fit seamlessly into their environment and to provide the functionalities expected by users which are often more sustainable than the environment, applications must dynamically adapt to these changes. Each of these variable phenomena pursues its own dynamic. The challenge offered to adaptation mechanisms is to be able to consider them, with suitable dynamics.For this purpose, we propose an architectural model and an adaptation mechanism. The architectural model is based on four levels organized hierarchically according to their complexity and to the dynamics they can offer. We combine to this architectural model an adaptation mechanism. Based on the separation of concerns principle, our mechanism allows us to consider the variability of the system. Due to the unpredictability of the environment, the sets of adaptations that will be deployed by the upper levels of the architecture may not have been anticipated at design time. Also, thanks to some logical and temporal properties, these adaptations can be composed in non-anticipated way and with appropriate response time. The proposed mechanism, called cascaded aspects, is implemented using Aspects of Assembly and the WComp execution platform.En informatique ambiante, les applications sont construites en faisant interagir entre eux des objets informatisés et communicants appelés dispositifs. Parce que ces dispositifs peuvent être mobiles ou subir des pannes, cette infrastructure évolue dynamiquement et de manière imprévisible. Aussi, pour s’insérer de manière transparente dans leur environnement et fournir les fonctionnalités attendues par les utilisateurs, bien souvent plus pérennes que l’environnement sur lequel elles reposent, les applications doivent s’adapter dynamiquement à ces évolutions. Ces phénomènes variables poursuivant leur propre dynamique, le défi proposé aux mécanismes d’adaptation est d’être capable de les prendre encompte, avec une dynamique adaptée à chacun d’entre eux.Dans cette optique, nous proposons un modèle architectural ainsi qu’un mécanisme d’adaptation. Le modèle architectural repose sur quatre niveaux organisés hiérarchiquement en fonction de leur complexité et de la dynamique qu’ils peuvent offrir. Nous lui associons un mécanisme d’adaptation qui, à partir du principe de séparation des préoccupations permet d’exprimer la variabilité du système. En raison de l’imprévisibilité de l’environnement, les ensembles d’adaptations qui seront déployées par les niveaux supérieurs de l’architecture ne peuvent pas nécessairement être anticipés à la conception. Aussi, grâce à un ensemble de propriétés logiques et temporelles, ces adaptations peuvent être composées de manière non-anticipée dans des temps de réponse adaptés. Le mécanisme d’adaptation proposé, appelé cascade d’aspects, est expérimenté en se basant sur les Aspects d’Assemblages et la plateforme d’exécution WComp

    Fundamental understanding and future guidance for handheld computers in the rail industry

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    Advances in mobile computing technology and software applications have led to an expansion in potential uses for handheld computers for various tasks. One strong application area is in maintenance and inspection. Network Rail has been progressively developing and applying handheld computers to field-based maintenance and inspection operations, with the aims of improving work productivity and quality, and personal and system safety. However, it is clear that these aims so far have been achieved with varying degrees of success. Handheld computer devices have the potential to enhance the procedure of performing the tasks in many different ways. However, the current handheld computers introduced to maintenance and inspection tasks in Network Rail have principally been designed as data entry tools and in most cases the primary objective is to reduce the amount of paper work and the associated costs and errors. This highlights the need for fundamental research into the ways in which handheld computer technologies should be specified, designed and implemented for effective use in a complex distributed environment such as the rail industry. The main purpose of this research was to study the applications of handheld computers in the rail industry and to generate a set of design principles for development of future systems within Network Rail. The findings of this research have contributed to the identification of human factors principles that need to be considered for design and implementation of successful handheld computer applications. A framework was also developed to summarise and organise information and functional requirements of maintenance workers. Investigating maintenance workers’ requirements through interviews and observations emphasised the importance of rail specific spatial information and the benefits of providing this knowledge to maintenance workers through a mobile computing device which is portable and easy to use. However, displaying rail specific spatial information on the small screen of a handheld computer introduces various HCI issues and challenges. These were addressed in part through a programme of experiments, and therefore the final section of this research focused on examining fundamental aspects of presenting rail specific spatial information on handheld computer screens. The main findings from different stages of this research have been collated into a set of recommendations for design and development of usable and useful applications for handheld computer devices in the rail industry
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