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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

UbiPri : middleware para controle e gerenciamento de privacidade em ambientes ubíquos / UBiPri : middleware control and privacy management in ubiquitous environments

Leithardt, Valderi Reis Quietinho January 2015 (has links)
Atualmente em vários países já existem mais dispositivos e meios de comunicações que habitantes e a medida que a tecnologia avança a troca de informação tende a aumentar exponencialmente. Com isso, ganha destaque a área denominada computação ubíqua, que visa o desenvolvimento de aplicativos para automatizar processos, antes manuais, a fim de proporcionar conforto, rapidez e conexão aos usuários com seus dispositivos. Nos estudos realizados decorrer desta tese identificou–se a necessidade de desenvolver e controlar informações privadas fundamentadas no local, aqui denominado ambiente ubíquo. O problema de pesquisa identificado foi a grande heterogeneidade de dispositivos e comunicações nestes sistemas, tornando-os vulneráveis e expondo os dados de seus usuários. Assim, observou-se a necessidade de um modelo taxonômico de privacidade que engloba características necessárias para controlar e gerenciar a privacidade de dados em ambientes ubíquos. A partir dessa taxonomia desenvolveu–se um protótipo com base em um middleware estruturado em camadas necessárias para prover os controles e gerenciamentos necessários nestes ambientes. Os primeiros testes e resultados se mostraram promissores, tendo seus resultados publicados em conferências internacionais da área que nortearam os estudos para uma melhoria do tratamento e filtragem de dados. Também foi possível a ampliação dos controles e gerenciamento de parâmetros automáticos com aumento e redução de definição do tipo de perfil do usuário em adição são apresentados os resultados obtidos em diferentes cenários de uso e aplicação. Para tanto, o protótipo desenvolvido permite selecionar opções de variáveis atribuídas individualmente a cada ambiente de acordo com suas necessidades, com isso, a solução proposta visa ser empregada no gerenciamento de privacidade em ambientes ubíquos. Os resultados obtidos nos testes realizados comprovam a viabilidade e contribuição cientifica do modelo desenvolvido. O aplicativo UbiPri foi disponibilizado para utilização no google play store, podendo ser instalado e configurado na plataforma android. / Currently in many countries there are already more devices and communication means inhabitants and as technology advances the exchange of information tends to increase exponentially. As a result, stands out the area called ubiquitous computing, which aims to develop applications to automate processes before hand in order to provide comfort, speed and connecting users with their devices. In studies carried out throughout this thesis it identified the need to develop and control private information based on location, here called ubiquitous environment. The identified research problem was the great heterogeneity of devices and communications in these systems, making them vulnerable and exposing the data of its users. Thus, there was the need for a taxonomic model of privacy that encompasses features needed to control and manage data privacy in ubiquitous environments. From this taxonomy developed a prototype based on a middleware structured in layers to provide the necessary controls and managements required in these environments. The first tests and results were promising, with the results published in international conferences in the area that guided the studies for improved treatment and filtering of data. It was also possible the expansion of controls and management parameters with automatic increase and decrease setting in the user profile type in addition the results obtained are presented in different usage scenarios and application. Thus, the prototype allows you to select options variables individually assigned to each environment according to their needs, with it, the proposed solution is intended to be used in the privacy management in ubiquitous environments. The results obtained in the tests prove the feasibility and scientific contribution of the developed model. The UbiPri application was made available for use in the google play store and can be installed and configured on android platform.
92

On the Selection of Just-in-time Interventions

Jaimes, Luis Gabriel 20 March 2015 (has links)
A deeper understanding of human physiology, combined with improvements in sensing technologies, is fulfilling the vision of affective computing, where applications monitor and react to changes in affect. Further, the proliferation of commodity mobile devices is extending these applications into the natural environment, where they become a pervasive part of our daily lives. This work examines one such pervasive affective computing application with significant implications for long-term health and quality of life adaptive just-in-time interventions (AJITIs). We discuss fundamental components needed to design AJITIs based for one kind of affective data, namely stress. Chronic stress has significant long-term behavioral and physical health consequences, including an increased risk of cardiovascular disease, cancer, anxiety and depression. This dissertation presents the state-of-the-art of Just-in-time interventions for stress. It includes a new architecture. that is used to describe the most important issues in the design, implementation, and evaluation of AJITIs. Then, the most important mechanisms available in the literature are described, and classified. The dissertation also presents a simulation model to study and evaluate different strategies and algorithms for interventions selection. Then, a new hybrid mechanism based on value iteration and monte carlo simulation method is proposed. This semi-online algorithm dynamically builds a transition probability matrix (TPM) which is used to obtain a new policy for intervention selection. We present this algorithm in two different versions. The first version uses a pre-determined number of stress episodes as a training set to create a TPM, and then to generate the policy that will be used to select interventions in the future. In the second version, we use each new stress episode to update the TPM, and a pre-determined number of episodes to update our selection policy for interventions. We also present a completely online learning algorithm for intervention selection based on Q-learning with eligibility traces. We show that this algorithm could be used by an affective computing system to select and deliver in mobile environments. Finally, we conducts posthoc experiments and simulations to demonstrate feasibility of both real-time stress forecasting and stress intervention adaptation and optimization.
93

Architectures et mécanismes de sécurité pour l'auto-protection des systèmes pervasifs

He, Ruan 30 November 2010 (has links) (PDF)
Contributions principales Les éléments précédents identifient les principes de conception de base pour construire un canevas logiciel d'auto-protection. Différentes technologies peuvent être choisies pour réaliser ces principes. Les contributions principales de cette thèse décrivent des mécanismes développés et mis en œuvre pour réaliser notre canevas logiciel d'auto-protection. Il s'agit des éléments suivants : - Une architecture a trois couches pour l'auto-protection : un espace d'exécution fournit un environnement d'exécution pour des applications; un plan de contrôle supervise l'espace d'exécution ; et un plan autonome guide le plan de contrôle en prenant en compte l'etat du systeme, l'evolution des risques, la strategie de securite definie par l'administrateur, et les preferences de l'utilisateur. - Une approche du contrôle d'acces a base d'attributs: l'approche proposee (appelee G-ABAC) exprime les politiques d'autorisation en se basant sur des attributs. Cette approche apporte a la fois une neutralite vis-a-vis du modele de contrôle d'acces, et une flexibilite permettant des manipulations elementaires sur ces politiques. - Un canevas logiciel a base de politiques pour realiser la gestion autonome de la securite : l'approche a base de politiques a montre ses avantages pour l'administration des systemes complexes et dynamiques. Un canevas logiciel autonome de politiques de securite (ASPF) fournit une solution coherente et decentralisee pour administrer les politiques d'autorisation pour les systemes pervasifs a grande echelle. L'integration des patrons autonomes ameliore egalement la souplesse et la facilite d'adaptation au contexte. - Un noyau de securite embarque pour l'application des politiques de contrôle d'acces : les politiques d'autorisation denies precedemment sont appliquees par une architecture d'autorisation au niveau du systeme d'exploitation. Ce noyau appele VSK contrôle l'acces aux ressources d'une maniere dynamique an de reduire le surcoût des mecanismes d'autorisation. Ce mecanisme permet egalement de supporter dierents types de politiques d'autorisation. - Un langage dedie (Domain-Specic Language ou DSL) pour la specication de politiques d'adaptation : toutes les adaptations de notre canevas logiciel d'auto-protection de bout en bout sont contr^olees par des strategies de haut niveau appelees politiques d'adaptation. Un DSL tenant compte de nombreux facteurs pour les decisions d'adaptation. est deni pour specier ces politiques.
94

Découverte de services sensible à la qualité de service dans les environnements de l'informatique diffuse.

Liu, Jinshan 11 July 2006 (has links) (PDF)
With the advent of portable devices (e.g., smartphones) and the advances in wireless networking technologies (e.g., WLAN, GPRS, UMTS), the vision of ubiquitous computing is becoming a reality. It aims to facilitate user tasks through the seamless utilization of heterogeneous computing and communication capabilities (represented as services) available in the environment. Service discovery, which is necessary for achieving the above goal, must be aware of the service's non-functional properties due to the challenges posed by ubiquitous computing, such as device portability and mobility. This thesis proposes an overall solution that supports QoS-aware service discovery in ubiquitous computing environments. Our contribution lies in substantiating QoS awareness in the following three aspects. Firstly, during the process of discovering services, the expiring wireless links resulting from device mobility are identified and avoided since they cause service failures and thus hamper service reliability. Secondly, as mu tiple services can be discovered, a comprehensive utility function is proposed to evaluate services in terms of their various non-functional properties, meanwhile taking into account the service user's preferences among them, for the purpose of selecting the best one. Thirdly, to avoid untrustworthy services, a distributed reputation mechanism is proposed to facilitate the evaluation of the service host's trustworthiness. The above three proposed solutions are extensively evaluated respectively, based on analysis and simulation. They are further incorporated into a middleware that supports QoS aware Web service discovery in ubiquitous computing environments. A prototype implementing the middleware is deployed and evaluated. The results show that the overhead introduced by QoS awareness seems reasonable.
95

A pervasive information framework based on semantic routing and cooperative caching

Chen, Weisong, January 2004 (has links)
Thesis (M. Phil.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.
96

Semantic-Based Context-Aware Service Discovery in Pervasive-Computing Environments

El-Sayed, Abdur-Rahman January 2006 (has links)
Recent technological advancements are enabling the vision of pervasive or ubiquitous computing to become a reality. Service discovery is vital in such a computing paradigm, where a great number of devices and software components collaborate unobtrusively and provide numerous services. Current service-discovery protocols do not make use of contextual information in discovering services, and as a result, fail to provide the most appropriate and relevant services for users. In addition, current protocols rely on keyword-based search techniques and do not consider the semantic description of services. Thus, they suffer from poor precision and recall. To address the need for a discovery architecture that supports the envisioned scenarios of pervasive computing, we propose a context-aware service-discovery protocol that exploits meaningful contextual information, either static or dynamic, to provide users with the most suitable and relevant services. The architecture relies on a shared, ontology-based, semantic representation of services and context to enhance precision and recall, and to enable knowledge sharing, capability-based search, autonomous reasoning, and semantic matchmaking. Furthermore, the architecture facilitates a dynamic service-selection mechanism to filter and rank matching services, based on their dynamic contextual attributes, which further enhances the discovery process and saves users time and effort. Our empirical results indicate the effectiveness and feasibility of the proposed architecture.
97

Non-Intrusive Computing

Chen, Hao January 2008 (has links)
Pervasive computing is an important trend today. It concerns devices and services in a smart space that interact with users in a simple, natural, and harmonious way. Many problems in this domain have been studied from different perspectives in various projects. However, one important characteristic of pervasive computing, which is how to make it non-intrusive so that users can focus on their tasks, has received little formal attention. Nowadays, many computing entities including smart devices, and software components, are involved in our daily lives, and users need to deal with them as well as with other people. Besides, people are easy to reach with multiple devices. We believe there should be a systematic way to help users avoid intrusive ones. We propose a model for posing and answering two questions: will an interaction intrude on its receiver if delivered, and given that the interaction is deliverable, how can it be delivered effectively and not too overtly? With this model, the intrusion problem is analyzed and the essential factors are identified. A quantitative approach is used, so that factors have quantitative values for comparison and computation. We also apply context to refine them in order to achieve better results. We then illustrate how to materialize the model and build a system whose design is inspired by the Jabber framework that includes a collection of standards, technologies, and projects for instant messaging. The discussion is at a general level that does not depend on Jabber. However, by choosing Jabber in implementation, we reuse existing software and technologies, and benefit from Jabber/XMPP standardization, its low entry barrier for application developers, and its rich community support. The main contributions of our work are two-fold. First, we propose a model for intrusiveness in pervasive computing. Second, we address the problem at the system level by designing and realizing it. We also make use of standardized instant-messaging technologies, more precisely Jabber, in the system instantiation to reuse existing software, making the system more flexible and extensible.
98

Smart assistants for smart homes

Rasch, Katharina January 2013 (has links)
The smarter homes of tomorrow promise to increase comfort, aid elderly and disabled people, and help inhabitants save energy. Unfortunately, smart homes today are far from this vision – people who already live in such a home struggle with complicated user interfaces, inflexible home configurations, and difficult installation procedures. Under these circumstances, smart homes are not ready for mass adoption. This dissertation addresses these issues by proposing two smart assistants for smart homes. The first assistant is a recommender system that suggests useful services (i.e actions that the home can perform for the user). The recommended services are fitted to the user’s current situation, habits, and preferences. With these recommendations it is possible to build much simpler user interfaces that highlight the most interesting choices currently available. Configuration becomes much more flexible: since the recommender system automatically learns user habits, user routines no longer have to be manually described. Evaluations with two smart home datasets show that the correct service is included in the top five recommendations in 90% of all cases. The second assistant addresses the difficult installation procedures. The unique feature of this assistant is that it removes the need for manually describing device functionalities (such descriptions are needed by the recommender system). Instead, users can simply plug in a new device, begin using it, and let the installation assistant identify what the device is doing. The installation assistant has minimal requirements for manufacturers of smart home devices and was successfully integrated with an existing smart home. Evaluations performed with this smart home show that the assistant can quickly and reliably learn device functionalities. / <p>QC 20130924</p>
99

Semantic-Based Context-Aware Service Discovery in Pervasive-Computing Environments

El-Sayed, Abdur-Rahman January 2006 (has links)
Recent technological advancements are enabling the vision of pervasive or ubiquitous computing to become a reality. Service discovery is vital in such a computing paradigm, where a great number of devices and software components collaborate unobtrusively and provide numerous services. Current service-discovery protocols do not make use of contextual information in discovering services, and as a result, fail to provide the most appropriate and relevant services for users. In addition, current protocols rely on keyword-based search techniques and do not consider the semantic description of services. Thus, they suffer from poor precision and recall. To address the need for a discovery architecture that supports the envisioned scenarios of pervasive computing, we propose a context-aware service-discovery protocol that exploits meaningful contextual information, either static or dynamic, to provide users with the most suitable and relevant services. The architecture relies on a shared, ontology-based, semantic representation of services and context to enhance precision and recall, and to enable knowledge sharing, capability-based search, autonomous reasoning, and semantic matchmaking. Furthermore, the architecture facilitates a dynamic service-selection mechanism to filter and rank matching services, based on their dynamic contextual attributes, which further enhances the discovery process and saves users time and effort. Our empirical results indicate the effectiveness and feasibility of the proposed architecture.
100

Non-Intrusive Computing

Chen, Hao January 2008 (has links)
Pervasive computing is an important trend today. It concerns devices and services in a smart space that interact with users in a simple, natural, and harmonious way. Many problems in this domain have been studied from different perspectives in various projects. However, one important characteristic of pervasive computing, which is how to make it non-intrusive so that users can focus on their tasks, has received little formal attention. Nowadays, many computing entities including smart devices, and software components, are involved in our daily lives, and users need to deal with them as well as with other people. Besides, people are easy to reach with multiple devices. We believe there should be a systematic way to help users avoid intrusive ones. We propose a model for posing and answering two questions: will an interaction intrude on its receiver if delivered, and given that the interaction is deliverable, how can it be delivered effectively and not too overtly? With this model, the intrusion problem is analyzed and the essential factors are identified. A quantitative approach is used, so that factors have quantitative values for comparison and computation. We also apply context to refine them in order to achieve better results. We then illustrate how to materialize the model and build a system whose design is inspired by the Jabber framework that includes a collection of standards, technologies, and projects for instant messaging. The discussion is at a general level that does not depend on Jabber. However, by choosing Jabber in implementation, we reuse existing software and technologies, and benefit from Jabber/XMPP standardization, its low entry barrier for application developers, and its rich community support. The main contributions of our work are two-fold. First, we propose a model for intrusiveness in pervasive computing. Second, we address the problem at the system level by designing and realizing it. We also make use of standardized instant-messaging technologies, more precisely Jabber, in the system instantiation to reuse existing software, making the system more flexible and extensible.

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