PRIVED: a Privacy Model for Heterogeneous Mobile Networks

We propose a network-oriented privacy model (PRIVED) composed by a well defined information model, using events, information sets and relationships to define the conceptual privacy relationships that can occur in the network. We propose formal rules and a network instantiation, using linkability and correlation as the main tools for network applicability. We also use the model to determine the best approaches towards privacy protection in the network, resulting in a vertical/horizontal network privacy dichotomy

FastM: Design and Evaluation of a Fast Mobility Mechanism for Wireless Mesh Networks

Although there is a large volume of work in the literature in terms of mobility approaches for Wireless Mesh Networks, usually these approaches introduce high latency in the handover process and do not support realtime services and applications. Moreover, mobility is decoupled from routing, which leads to inefficiency to both mobility and routing approaches with respect to mobility. In this paper we present a new extension to proactive routing protocols using a fast mobility extension, FastM, with the purpose of increasing handover performance in Wireless Mesh Networks. With this new extension, a new concept is created to integrate information between neighbor wireless mesh routers, managing locations of clients associated to wireless mesh routers in a certain neighborhood, and avoiding packet loss during handover. The proposed mobility approach is able to optimize the handover process without imposing any modifications to the current IEE 802.11 MAC protocol and use unmodified clients. Results show the improved efficiency of the proposed scheme: metrics such as disconnection time, throughput, packet loss and control overhead are largely improved when compared to previous approaches. Moreover, these conclusions apply to mobility scenarios, although mobility decreases the performance of the handover approach, as expected

Fatores e estratégias promotores do interesse pela leitura na Educação Pré-Escolar e no 1.º Ciclo do Ensino Básico

Mestrado, Educação Pré-Escolar e Ensino do 1.º Ciclo de Ensino Básico, 17 de Abril de 2017, Universidade dos Açores.No presente Relatório de Estágio procurámos analisar criticamente as práticas pedagógicas desenvolvidas na Educação Pré-Escolar e no 1.º Ciclo do Ensino Básico, em particular no que respeita à compreensão dos fatores que aproximam as crianças da leitura, tendo em vista a seleção das melhores estratégias de ensino para promover esse interesse e o desenvolvimento das competências de leitura das crianças. Neste sentido, desenvolvemos um trabalho de natureza predominantemente qualitativa, numa perspetiva de investigação-ação, pelo que os dados e as conclusões obtidas não podem ser alvo de generalização para outros grupos de indivíduos. Assim, na Educação Pré-Escolar verificou-se uma complementaridade entre os fatores e as estratégias, visto que através destas conseguimos descobrir os fatores de (des)interesse pela leitura do nosso grupo de crianças e, consequentemente, selecionar novas estratégias adequadas a esses interesses. De uma forma geral, apercebemo-nos no início do estágio que este grupo não utilizava a biblioteca no Tempo de Atividades Autónomas. Contudo, através das estratégias aplicadas as crianças começaram a aproximar-se da leitura, chegando a afirmar que aprenderam a ler. Quanto ao 1.º Ciclo do Ensino Básico, aplicou-se o questionário de Wigfield e Guthrie (1997) com o intuito de perceber quais os fatores que aproximam os alunos da leitura e em função dos mesmos selecionar as estratégias de ensino. Apesar de os alunos da turma, no geral, gostarem de ler, através da segunda aplicação do questionário, no final do estágio, verificámos as nossas estratégias terão influenciado positivamente esse interesse, fazendo subir os resultados mais baixos. Relativamente a ambos os contextos de Estágio procurou-se também desenvolver a compreensão leitora, de acordo com os vários níveis proposto por Viana et al. (2010), segundo estratégias de pré-leitura, leitura e pós-leitura. Foi notório que prevaleceram as questões de compreensão literal, à semelhança dos estudos de Ramos (2012) e Pereira (2015). O percurso de intervenção e investigação que culmina neste trabalho foi de crucial importância para a minha formação, na medida que me permitiu refletir sobre as minhas ações e, assim, evoluir como profissional.ABSTRACT: The present final Report sought to critically analyse the pedagogical practices developed in pre-school education and in elementary school, in particular regarding the comprehension of the factors that bring the children closer to reading, in view of the selection of the best educational strategies to promote this specific interest and to develop the reading competences of the children. In this sense, we developed a study having a predominantly qualitative nature, in an investigation-action perspective, whereby the data and conclusions achieved cannot be extrapolated to other groups of individuals. Hence, in the pre-school education it was verified a complementarity between the factors and the strategies, since through these we were able to identify the factors of (un)interest for reading of our focus children group and, consequently, we were able to select new strategies suitable for those interests. In general, we realized at the beginning to the study, that this focus group did not use the library in the “Autonomous Activities Period”. Nevertheless, through the strategies implemented the children started to approach reading, even claiming that they learned how to read. Regarding the Elementary school, we applied the Wigfield and Guthrie questionnaire (1997) with the aim of understanding which factors bring the students closer to reading and, regarding those, select the teaching strategies. Although the class students, in general, liked reading, through the second application of the questionnaire, at the end of the study, we verified that our strategies may have positively influenced this interest, by raising the lowest results. Considering both contexts of this final report, we sought also to develop de reading comprehension, in accordance to the several levels proposed by Viana et al. (2010), regarding pre-reading, reading and post-reading strategies. It was evident that prevailed the questions of literal comprehension, similarly to the study of Ramos (2012) and Pereira (2015). The journey of intervention and investigation that culminates in this final work was of crucial importance for my competences, in the sense that it allowed me to consider and think about my actions, and, therefore, evolve as a professional

A Cross-System Approach for Multimedia Services with IP Multicast in 4G Networks

The increased demand for multimedia services by mobile end users in recent years have driven both Broadcast and Wireless Network operators to develop new systems and architectures for the deployment of such services. The proposed solutions are nonetheless limited either in terms of QoS or Capabilities to deliver new interactive services. This paper highlights strengths and drawbacks of the existing technologies in terms of QoS, Security and Mobility. In order to fill the gap between current solutions we propose a new architecture that builds itself on the synergies created by a heterogeneous network made of existing delivering technologies, such as 3GPP/MBMS and DVB, where services can be delivered to end-users in the most appropriate way for end-users and operators alike. A prototype implementation is further described.EU project - IST-2002- 506997 Daidalos I

Determining the orientation parameters using the mems accelerometer and magnetometer

Для определения положения объекта на поверхности Земли наибольшее распространение получили географические координаты, с помощью которых можно наблюдать ориентацию и навигацию объекта. Информация об ориентации объекта в пространстве является основополагающей для задач навигации этого объекта на Земле [2]. В географической системе координат задача ориентации понимается как определение углового положения относительно горизонтальной плоскости и направления на север. Одним из самых известных устройств, используемых для определения углового положения объекта относительно направления на магнитный север, является магнитный компас. В этой работе будет рассмотрен современный электронный компас, основанный на тр?хосных МЭМС акселерометре и магнетометре.This article describes the temperature control system for a downhole tool. The peculiarity of this system isthat it is using a heater and an active cooler which are controlled by pulse width modulation. The basis of such asystem is taken from the thermostatic scheme of the inclinometer IGN 100-100 / 60-A. However, this scheme hasserious drawback - conducted interference. These disturbances affect the operation of a downhole power supply,and therefore the entire electronic inclinometer instrumentation. This article briefly describes the principle of thetemperature control system. Furthermore, reasons for this interference are discussed in detail, calculated the valueof failures in the selection of power, the graphs clearly show the changes in the signal. The problematic elements ofthe scheme, affecting the appearance of interference, are identified. The possible solutions to eliminate thisinterference are analyzed, stating the shortcomings of each of the solutions

Development of a Hybrid Simulation and Emulation Testbed For VANETs

In the area of Intelligent Transportation System traffic efficiency and safety for users have become very popular topics and have triggered extensive research in Vehicular Ad-Hoc Networks (VANETs). Traditional methods for reaserch and development like field testing and simulation have been used. But field testing is usually very expensive and simulation lacks accuracy in wireless environments. This article aims to introduce a hybrid solution that combines the simulation and emulation methods. The proposed solution is implemented in a testbed for VANETs. The resulting testbed would allow multiple real routing instances to run simultaneously on a simulated environment. And to provide performance measures such as resource consumption and scalability