Submitted by Geyciane Santos (geyciane_thamires@hotmail.com) on 2015-06-18T13:09:51Z No. of bitstreams: 1 Dissertação - Daniel Frazão Luiz.pdf: 4676951 bytes, checksum: fcf45baa0188561b5fb832534e0a0736 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-06-18T20:31:05Z (GMT) No. of bitstreams: 1 Dissertação - Daniel Frazão Luiz.pdf: 4676951 bytes, checksum: fcf45baa0188561b5fb832534e0a0736 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-06-18T20:32:03Z (GMT) No. of bitstreams: 1 Dissertação - Daniel Frazão Luiz.pdf: 4676951 bytes, checksum: fcf45baa0188561b5fb832534e0a0736 (MD5) / Made available in DSpace on 2015-06-18T20:32:03Z (GMT). No. of bitstreams: 1 Dissertação - Daniel Frazão Luiz.pdf: 4676951 bytes, checksum: fcf45baa0188561b5fb832534e0a0736 (MD5) Previous issue date: 2014-02-25 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Many applications in Wireless Sensor Networks (WSNs) consider remote and large scale monitoring. For those scenarios, the whole network is hardly fully connected all the time. A possible vision is the union of WSNs and Disruptive Tolerant Network(DTNs) concepts, where mobile nodes make collect data in sparse networks and deliver them to a base station. This work presents a buffer management strategy, which is a basic principle in DTN networks. The proposed solution considers the global coverage to choose which messages are dropped, therefore, minimizing the impact on monitoring application. Such solution is important for WSNs applications with limited resources. We show through simulation that the proposed Coverage-Based Drop-Policy in Wireless Sensor Network with Disruptive Connections (CBDP) improves the network coverage compared to traditional DTN drop policies like Drop Last (DL) and Drop First (DF). / Sensores Sem Fio (RSSFs) consideram o monitoramento de localidades afastadas, de difícil acesso e em larga escala. Para tais cenários, é difícil imaginar que todos os segmentos da rede estão interconectados ou têm conectividade direta com uma central de processamento. Uma visão possível é o uso conjunto dos conceitos de RSSFs e redes tolerantes a desconexões (DTNs - Disruptive-tolerant networks), em que nós móveis podem ser responsáveis por coletar dados de redes esparsas e entregá-los a um ponto central. Esta dissertação apresenta uma estratégia de gerenciamento de buffers, que é uma das funções fundamentais das DTNs. A solução proposta baseia-se no cálculo da cobertura para o descarte de pacotes de dados que menos contribuam para a cobertura global do sistema, favorecendo sua aplicação em redes de sensores com recursos limitados mas de alta escala. Através de simulações, mostramos que a Política de Descarte Baseada em Cobertura (CBDP) melhora a cobertura da rede em comparação às políticas de descarte normalmente encontradas nas DTNs, como Drop Last (DL) e Drop First (DF).

Os dispositivos móveis passaram por grandes transformações na última década e tornaram-se complexos computadores dotados de grande poder de processamento e memória, além de prover aos usuários diversos recursos como sensores e câmeras de alta resolução. O uso de dispositivos móveis para diversas tarefas aumentou consideravelmente, o que levantou uma grande preocupação com o o alto consumo de energia desses dispositivos. Portanto, estudos tem sido realizados no sentido de encontrar soluções para diminuir o custo de energia das aplicações que executam em dispositivos móveis. Uma das alternativas mais utilizadas é o \\textit{computation offloading}, cujo objetivo é transferir a execução de uma tarefa para uma plataforma externa com o intuito de aumentar desempenho e reduzir consumo de recursos, como a bateria, por exemplo. Decidir sobre usar ou não esta técnica implica entender a influência de fatores como a quantidade de dados processados, a quantidade de computação envolvida, e o perfil da rede. Muitos estudos tem sido realizados para estudar a influência de diversas opções de rede wireless, como 3G, 4G e Wifi, mas nenhum estudo investigou a influência das escolhas de comunicação no custo de energia. Portanto, o objetivo deste trabalho é apresentar uma investigação sobre a influência da quantidade de dados, da quantidade de computação e dos protocolos de comunicação ou estilo arquitetural no consumo de energia quando a técnica de \\textit{computation offloading} é utilizada. Neste estudo, foram comparados REST, SOAP, Socket e RPC na execução de algoritmos de ordenação de diferentes complexidades aplicados sobre vetores de diversos tamanhos e tipos de dados. Os resultados mostram que a execução local é mais econômica com algoritmos menos complexos, pequeno tamanho de entrada e tipo de dados menos complexos. Quando se trata de execução remota, o REST é a escolha mais econômica seguida por Socket. Em geral, REST é mais econômico com vetores do tipo Object, independentemente da complexidade do algoritmo e tamanho do vetor, enquanto Socket é mais econômico com entradas maiores e com vetores de tipos primitivos, como Int e Float / Mobile devices have significantly changed in the last decade and they become complex computer machines equipped with large processing power and memory. Moreover, they provide users with several resources such as sensors and high resolution cameras. The usage of mobile devices has significantly increased in the past years, which raised an important concern regarding the high energy consumption. Therefore, several investigations have been conducted aiming at finding solutions to reduce the energy cost of mobile applications. One of the most used strategy is called computation offloading, whose main goal is to transfer the execution of a task to an external platform aiming at increasing performance and reducing resource consumption, including the battery. Deciding towards offloading certain tasks requires to understand the influence of the amount of data, amount of computation, and the network profile. Several studies have investigated the influence of different wireless flavours, such as 3G, 4G and wifi, but no study has investigated the influence of the communication choices on the energy cost. Therefore, the purpose of this research project is to present an investigation on the influence of the amount of data, amount of computation and the communication protocols and architectural style on the energy consumption in the context of the computation offloading technique. In this study, we compare REST, SOAP, Socket and RPC when executing algorithms of different complexities and different input sizes and types. Results show that local execution is more economic with less complex algorithms and small input data. When it comes to remote execution, REST is the most economic choice followed by Socket. In general, REST is the most economic choice when applied on Object type arrays, regardless the complexity and size, while Socket is the most economic choice with large arrays and primitive types such as integers and floats

Mobile health (mHealth) can be defined as the practice of medicine and public health supported by mobile computing technologies, such as mobile phones, PDAs, tablets, sensors and other wireless devices. Particularly in the case of mobile phones, there has been a significant increase in the number of lines, equipment, and network infrastructure in Low- and Middle-Income Countries (LMIC), allowing the adoption of mHealth systems efficiently. There are now several cases of systems for data collection focused on primary care, health surveillance and epidemiological research, which were adopted in these countries. Such systems provide health care managers information with higher quality and in a shorter time, which in turn improves their ability to plan actions and respond to emergencies. However, security is not included among the main requirements of such systems. Aiming to address this issue, we developed a survey about mHealth applications and research initiatives in Brazil, which shows that a reasonable number of papers only briefly (13%) or simply do not mention (40%) their security requirements. This survey also provides a discussion about the current state-of-art of Brazilian mHealth researches, including the main types of applications, target users, devices employed and the research barriers identified. After that, we present the SecourHealth, a security framework for mHealth data collection applications. SecourHealth was designed to cope with six main security requirements: support user registration and authentication mechanisms; treat network disconnections and delays; provide a secure data storage - even in case of possible theft or loss of equipment; allow secure data exchange between the device and server; enabling device sharing between users (i.e., health workers); and allow trade-offs between security, performance and usability. This thesis also describes in detail the framework modeling and development steps showing how it was integrated into an application for the Android platform. Finally, we benchmarked the cryptographic algorithms implemented, when compared to the overhead of using HTTPS protocol. / Saúde Móvel (mHealth) pode ser definida como a prática médica e a saúde pública suportadas por tecnologias de computação móvel, como: telefones celulares, PDAs, tablets, sensores e outros dispositivos sem fio. Particularmente no caso dos celulares, há um aumento expressivo no número de linhas, aparelhos, e na infraestrutura de rede em países de média e baixa renda (Low- Middle- Income Countries, LMIC), permitindo a adoção de sistemas mHealth de maneira eficiente. Existem, hoje, vários casos de sistemas de coleta de dados voltadas à atenção primária, vigilância (em saúde) e pesquisas epidemiológicas adotados nesses países. Tais sistemas fornecem aos gestores de saúde uma informação de melhor qualidade em menor tempo, que por sua vez melhoram a capacidade de planejamento e resposta a emergências. Contudo, nota-se um relaxamento no cumprimento de requisitos de segurança nestes sistemas. Com base nisso, foi feito um levantamento de aplicações e iniciativas de pesquisa em mHealth no Brasil, no qual se constatou que um número razoável de trabalhos mencionam fracamente (13%) ou não menciona (40%) os requisitos de segurança. Este levantamento também discute sobre o estado atual das pesquisas de mHealth no Brasil, os principais tipos de aplicações, os grupos de usuários, os dispositivos utilizados e as barreiras de pesquisa identificadas. Em seguida, este trabalho apresenta o SecourHealth, um framework de segurança voltado ao desenvolvimento de aplicações de mhealth para coleta de dados. O SecourHealth foi projetado com base em seis requisitos principais de segurança: suportar o registro e a autenticação do usuário; tratar a desconexão e os atrasos na rede; prover o armazenamento seguro de dados prevendo possibilidades de furto ou perda dos aparelhos; fazer transmissão segura de dados entre o aparelho e o servidor; permitir o compartilhamento de dispositivos entre os usuários (e.g., agentes de saúde); e considerar opções de compromisso entre segurança, desempenho e usabilidade. O trabalho também descreve com detalhes as etapas de modelagem e desenvolvimento do framework - que foi integrado a uma aplicação para a plataforma Android. Finalmente, é feita uma análise do desempenho dos algoritmos criptográficos implementados, considerando o overhead pelo simples uso do protocolo HTTPS.

Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-08-14T18:44:38Z No. of bitstreams: 1 AntonioPalmeiraFilho.pdf: 3164841 bytes, checksum: 23d94c0539749a601438bcd53f1d7384 (MD5) / Made available in DSpace on 2017-08-14T18:44:38Z (GMT). No. of bitstreams: 1 AntonioPalmeiraFilho.pdf: 3164841 bytes, checksum: 23d94c0539749a601438bcd53f1d7384 (MD5) Previous issue date: 2007-11-09 / Mobile devices have evolved from simple personal digital assistants or cell phones to cutting-edge personal digital assistants, aliasing or combining on-the- y video/audio acquisition and data processing. But giving the best usage to all this new technology in our day-by-day tasks still is challenging. The large variety of devices, the increasing need for ubiquitous mobile services and the network heterogeneity are just some problems developers may nd when deploying for the mobile world. With the popularization of the wireless network technologies, we can nd devices capable of establishing network connections using di erent technologies. Infrastructured networks support good bandwidth with low latency, but they demand an infrastructure of access points that are not available at any place. On the other hand, ad-hoc networks don't need an infrastructure and the communication is done in a peer-to-peer maner. The ad-hoc networks play an important rule in the environments made by mobile devices since they ensure high availability. Spontaneous networks are ad-hoc networks formed occasionally by users that wish to engage in some collaborative task, like a le sharing. In this work we describe a framework to help developers to easily create applications capable of managing and sharing digital content within groups of people in a spontaneous short-range ad-hoc network. We describe the framework architecture, its services and their relationship, as well as some usage scenarios, applications and related works. / Dispositivos móveis evoluíram de simples agendas, calendários ou telefones celulares para modernos assistentes pessoais, capazes de armazenar e processar áudio e vídeo em tempo real. Contudo, dar a melhor utilidade a esta tecnologia em nossas tarefas do dia-a-dia ainda é um desafio. A grande variedade de dispositivos, a crescente necessidade de serviços móveis pervasivos e a heterogeneidade das tecnologias de rede são apenas alguns exemplos dos problemas possivelmente encontrados pelos desenvolvedores ao produzir software para o mundo móvel. Com a popularização das tecnologias de rede, é cada vez mais comum encontrarmos dispositivos móveis capazes de estabelecer conexões através de diferentes tecnologias. Redes infra-estruturadas disponibilizam boas larguras de banda e baixa latência, porém necessitam de uma infra-estrutura de pontos de acesso nem sempre disponível. Por outro lado, as redes ad-hoc não necessitam de infra-estrutura e a comunicação entre seus nós é feita ponto a ponto, razão pela qual desempenham um importante papel nos ambientes formados por dispositivos móveis. Redes espontâneas são redes ad-hoc formadas ao acaso por usuários que desejam participar de alguma tarefa colaborativa, como o compartilhamento de arquivos. Neste trabalho apresentamos um framework cujo objetivo é ajudar os desenvolvedores a criar facilmente aplicações capazes de gerenciar e compartilhar conteúdo digital com grupos de usuários em redes ad-hoc espontâneas de curto alcance. São descritos a arquitetura do framework proposto, seus serviços e relacionamentos, assim como alguns cenários de uso, aplicações e trabalhos relacionados.

Thesis (DTech (Information Technology))--Cape Peninsula University of Technology, 2018. / The central thesis of this study is that a multi-factorial strategy model can be evolved to enable development agency to be an augmenter in the commercialisation of the mobile applications development SME sector through business model innovation in response to disruptive innovation. The concept of augmentation in the context of this study acknowledges that disruptive innovation is ubiquitous and that development agencies can help these SMEs to succeed through business model innovation. This can be achieved through the implementation of a multi-factorial strategy model. A multi-factorial strategy model in this context is regarded as a method or plan having stemmed or stemming from a number of different causes or influences detailing the logic and the key considerations on the path to defining an organisation’s strategy. The development agency can utilise it to determine the state of the business and what the appropriate response should be, by way of business model innovation in response to disruptive innovation. This study rests on three tenets, namely, the uncovering of the dimensions of business model innovation; the nature of disruption; and finally, the potential role of the development agency in supporting SMEs in the technology sector. The mobile application (app) economy has presented business potential for SMEs and this sector of the economy can be facilitated by development agencies. Governments make use of development agencies to assist, develop and support growth within a region through the provision of resources and assistance, usually from state organisations. The enterprise development strategy should ensure the viability of the business idea, which should lead to the creation of new business value. The fieldwork for this critical realist study consisted of five phases. Phase 1 involved interviews with academics from the four higher education institutions in the Western Cape; Phase 2 involved an interview with mobile application development SMEs; Phase 3 comprised a focused interview consisting of members from industry and the development agency; Phase 4 involved interviews with entrepreneurs within the innovation and technology sector; and Phase 5 involved interviews with development agencies supporting the development of SMEs. Despite their potential, mobile app development businesses in the Western Cape face difficulties in commercialising their applications. The study suggested that research is warranted around the establishment of a multi-factorial strategy model which could provide a strategy for enhanced commercialisation of mobile app development. This model would have to address a number of concerns, depending on the propensity of the business towards mobile app development. Research into what adjustments to the current business models of these businesses are required to enter into mobile app development was also recommended. The findings and interpretations of this critical realist study revealed a structured real world of the landscape of mobile application development in the Western Cape, South Africa, by identifying its key constructs. It then revealed that knowledge is socially produced by identifying the salient imperatives that inform the role of the development agent with respect to business model innovation and disruptive innovation. By means of critical discourse analysis of the views expressed by the respondents, it revealed the emancipation agenda of mobile application development in the Western Cape, South Africa. In doing so it also ultimately uncovered the generative mechanisms in understanding, amongst others, what the critical performance underpinnings are. It is recommended that the SME sector implement business model innovation to respond to disruptive innovation, defined as “emerging technology whose arrival in the marketplace signifies the eventual displacement of the dominant technology in that sector” (Ganguly, Nilchiani & Farr, 2010, p. 35). The proliferation of disruptive innovation has led to technological innovation and such innovation will impact on SMEs in South Africa. The concept of business model innovation suggests that SMEs should move to a progressive interdependent modality where they participate through their shared strengths. The collaboration with other mobile app development SMEs would allow for their independent weaknesses to be moderated. Through business model innovation, mobile app development SMEs should be able to respond to the disruptive innovation and ensure success and sustainability. The antidote to disruption should be progressive management by way of business model innovation. In this sense then, the antidote to disruptive innovation is a management response that should be understood across the sector in which the study is undertaken.

Thesis (DPhil (Informatics))--Cape Peninsula University of Technology, 2018. / As in many parts of the world, the need for healthcare services is increasing rapidly in South Africa. Owing to many official languages in the country, health service delivery is continuously challenged by spoken language and semantics. The challenges result to poor health services in many areas of the country. Thus, this study was undertaken with the aim: to develop a framework which can be used to guide the selection and implementation of mobile systems in the translation of language semantics for improved healthcare service delivery in South Africa. For this purpose, the study was based on one significant research question: How can the challenge(s) of semantics and language translation in South African healthcare delivery be addressed using mobile systems? In achieving the aim of the study, a qualitative study was conducted using the semi-strtructured interviews to collect the data. The analysis of the data was carried out using the hermeneutic approach within the interpretative paradigm, which was guided by two theories, actor network theory (ANT) and diffusion of innovation (DOI). The ANT was used to focus on the interaction and relationship between human and non-human actors within a heterogeneous networks, in the activities of healthcare. The DOI was employed to examine how mobiles systems can be diffused, in addressing the challenges and barriers which the health facilities encounter from language perspective. The case study approach was followed, based on three cases, two healthcare organisations, and a community in the northern part of South Africa were used in the study. Based on the analysis of the data, the influencing factors were found, and interpreted. The interpretation helps gain deeper understanding of the challenges, from which a framework (see Figure 6.5 in Chapter 6) was developed. From an understanding of the factors that influence language semantics, and its translaton by using mobile systems, challenges in the South African healthcare can be reduced, and quality improved. The way in which the theories were used brought a fresh perspective to the study. In practice, the framework can be used by both healthcare practitioners and ICT specialists to guide the selection, use and support of mobile systems for the translation of language semantics in South Africa. The complementary use of ANT and DOI in the study contributes methodologically.

<p>Machine learning is a rapidly developing field in computer research. Deep neural network architectures such as Resnet have allowed computers to process unstructured data such as images and videos with an extremely high degree of accuracy while at the same time managing to deliver those results with a reasonably low amount of latency. However, while deep neural networks are capable of achieving very impressive results, they are still very memory and computationally intensive, limiting their use to clusters with significant amounts of resources. This paper examines the possibility of running deep neural networks on mobile hardware, platforms with much more limited memory and computational bandwidth. We first examine the limitations of a mobile platform and what steps have to be taken to overcome those limitations in order to allow a deep neural network to operate on a mobile device with a reasonable level of performance. We then proceed into an examination of ApproxNet, a neural network designed to be run on mobile devices. ApproxNet provides a demonstration of how mobile hardware limits the performance of deep neural networks while also showing that these issues can be to an extent overcome, allowing a neural network to maintain usable levels of latency and accuracy.</p>

[pt] A computação ubíqua aliada ao avanço tecnológico de sensores definiu um novo cenário no qual a integração de diversos recursos computacionais pode contribuir para que um conjunto de serviços e funcionalidades esteja disponível ao usuário sempre que necessário. Um subconjunto desta área é de sistemas sensíveis às atividades realizadas por seus usuários, isto é, sistemas que utilizam informações sobre o que o usuário está fazendo. Nesses sistemas, mecanismos de inferência são essenciais para reconhecer ações do usuário e permitir que o comportamento do sistema se adapte a estas ações. Entretanto, como esses ambientes são caracterizados por uma elevada troca de informações, o desenvolvimento deste tipo de sistema não é uma tarefa trivial e possui como desafios: privacidade, desempenho, complexidade e ambigüidade das informações coletadas. O objetivo deste trabalho é propor uma arquitetura para sistemas de inferências de atividades do usuário. Para atingir esse objetivo, definimos um conjunto de componentes que representam funções especificas do processo de inferência. Com o objetivo de analisar a viabilidade da arquitetura proposta, desenvolvemos, avaliamos e relatamos um protótipo de sistema baseado na arquitetura. / [en] The ubiquitous computing combined with the advance of sensor technology creates a scenario in which the integration of several computing resources is used to keep a set of services and features available to the user whenever necessary. A particular trend in this area is the activity based systems, i.e., systems that are aware of the activity played by the user. In these systems, inference engine is essential to recognize user’s actions and allow the systems to adapt its behavior according to user’s actions. Though, the development of this type of systems is not a trivial task as the high rate of information exchanged brings challenges related to privacy, performance and information management. In this work we propose an architecture for activity inference systems. To achieve this goal, we define a set of components that perform important roles in the inference process. Finally, to show the feasibility of this approach, we designed, implemented and evaluated a system based on the proposed architecture.

Hearing loss can significantly hinder an individual's ability to engage socially and, when left untreated, can lead to anxiety, depression, and even dementia. The most common type of hearing loss is sensor-neural hearing loss that is treated using hearing aids (HAs). However, a significant fraction of individuals that may benefit from using HA do not use them and, the satisfaction of those that do, is only around 60%. Today, we have only a limited understanding regarding the factors that contribute to the low adoption and satisfaction rates. This is a limitation of existing laboratory-based assessment methods that cannot accurately predict the performance of HAs in the real-world as they do not fully reproduce the complexities of real-world environments. There four core contributions of my PhD thesis: i) the development new computer-based methods for assessing HAs in the real-world. Our approach is based on the insight that HA performance is intrinsically dependent on the context in which a HA is used. A context includes characteristics of the listening activity, social context, and acoustic environment. To evaluate this hypothesis, we have developed AudioSense, a system that uses mobile phones to jointly characterize the context of users and the performance of HAs. ii) We provide the first instance of characterization of the auditory lifestyle of hearing aid users, and the relationships that exist between the context and hearing aid outcomes. iii) We utilize the subjective data collected using AudioSense to build novel models that can predict the success of hearing aid prescriptions for new and experienced users. We also quantitatively prove the importance of collecting contextual information for evaluating hearing aids. iv) We use the objective audio data collected with AudioSense to predict contextual information like acoustic activity and noise level. This provides us a way to intelligently infer contextual information automatically and reduce the burden on the study participants.

Les réseaux ad hoc sont des réseaux distribués, auto-organisés ne nécessitant pas d'infrastructure. Les entités formant un tel réseau doivent collaborer afin d'assurer le bon fonctionnement des services réseaux, tel que le routage. Dans un tel environnement, de nombreux algorithmes développés pour le monde filaire ne peuvent être adaptés de façon naïve sans entraîner une congestion importante du réseau qui va réduire son efficacité. Notre travail de thèse se penche sur l'étude de la gestion de services. En effet, sans application, le développement d'une architecture comme les réseaux ad hoc est inutile. La gestion de services consiste à fournir tout les moyens possibles pour faciliter et rendre fiable l'utilisation d'applications distribuées. Nos travaux contribuent à l'étude de deux points précis de la gestion de services. Premièrement, nous fournissons un algorithme permettant de répartir efficacement une information dans le réseau en sélectionnant certains objets du réseau pour être des réplicats de l'information. Cet algorithme peut alors être utilisé pour publier les informations relatives à un service afin de permettre sa recherche. Deuxièmement, nous avons étudié la prédiction de déconnexion entrainée par la mobilité des noeuds. Nous proposons trois solutions basées sur la recherche d'ensemble de chemins disjoints, la recherche de liens critiques et la recherche de noeuds critiques. Les recherches que nous proposons sont entièrement réalisées à partir d'informations locales. Les résultats obtenus fournissent une base au développement d'un gestionnaire de services distribués. De plus, certains de nos algorithmes (comme la recherche d'ensembles de chemins disjoints) peuvent être réutilisés dans d'autres applications, comme le routage QoS multi-chemins.