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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.
131

Uso de informações de contexto em segurança computacional / Use of context information on computer security

Francisco Gomes Milagres 07 October 2004 (has links)
Diariamente, novos sistemas ubíquos são desenvolvidos e integrados ao nosso cotidiano, cuja presença às vezes não é percebida pelos seus usuários. O objetivo deste trabalho é investigar as questões de segurança e privacidade existentes nos paradigmas de computação ubíqua e ciente de contexto. Utilizando um protótipo de TV interativa - TV-I (Goularte, 2003) - que possui características de mobilidade e ciência de contexto, este trabalho define um conjunto de requisitos mínimos para a garantia de segurança e privacidade em sistemas ubíquos. É também objetivo deste trabalho utilizar informações contextuais para gerenciamento dinâmico de requisitos de segurança e privacidade por meio de políticas expressas em linguagem EPAL. Para validar os resultados desta pesquisa, foi implementado o Gerente de Segurança como um serviço do protótipo TV-I. A principal característica desse gerente é controlar o acesso a informações pessoais por meio de informações de contexto fornecidas pelo Gerente de Contexto, de autoria de Santos (2004) / Every day, new ubiquitous systems are being developed and integrated into our daily routines, whose presence is sometimes not even perceived by the casual user. The aim of this work is to investigate questions of security and privacy in ubiquitous and context aware computing. Using a prototype for interactive television - TV-I (Goularte, 2003) - that has characteristics of mobility and contextual-awareness, this work defines a set of basic requirements that are fundamental in order to guarantee security and privacy in ubiquitous systems. Furthermore, this work uses contextual information in order to dynamically manage security and privacy requirements according to security and privacy policies that are expressed in the EPAL language. In order to validate the experimental results, a Security Manager has been implemented as a service of the TV-I prototype. The principal characteristic of this manager is to enforce access control over the personal information using contextual information of the ubiquitous system, and which is supplied via the Context Manager, designed by Santos (2004).
132

A Distributed Context Simulation Component

Khan, Izhar Ahmed January 2011 (has links)
Mobile devices with access to large numbers of sensors with internet access move forwards the development of intelligent applications towards new shape of ubiquitous applications. In order to create such applications we need to be able to do simulations to test and deploy. Current simulators do not permit this since they are centralized and the information is not shared globally. Therefore we cannot use them to test application built on distributed sensor information. I selected Siafu as the simulator component. In the next step, the simulator was customized according to the requirements of the project. There are different possibilities to achieve this task, but a simple GUI is made to control the simulator.The end result is a complete architecture for simulating context aware scenarios. The implementation is tested by running the simulator and dumping the context data into the PGRID overlay. For future work, implementing proximity estimation between the agents will be a good idea and can be interesting as well.
133

Context-aware access control in ubiquitous computing (CRAAC)

Ahmed, Ali Ahmed Ali January 2010 (has links)
Ubiquitous computing (UbiComp) envisions a new computing environment, where computing devices and related technology are widespread (i.e. everywhere) and services are provided at anytime. The technology is embedded discreetly in the environment to raise users' awareness. UbiComp environments support the proliferation of heterogeneous devices such as embedded computing devices, personal digital assistants (PDAs), wearable computers, mobile phones, laptops, office desktops (PCs), and hardware sensors. These devices may be interconnected by common networks (e.g. wired, wireless), and may have different levels of capabilities (i.e. computational power, storage, power consumption, etc). They are seamlessly integrated and interoperated to provide smart services (i.e. adaptive services). A UbiComp environment provides smart services to users based on the users' and/or system's current contexts. It provides the services to users unobtrusively and in turn the user's interactions with the environment should be as non-intrusive and as transparent as possible. Access to such smart services and devices must be controlled by an effective access control system that adapts its decisions based on the changes in the surrounding contextual information. This thesis aims at designing an adaptive fine-grained access control solution that seamlessly fits into UbiComp environments. The solution should be flexible in supporting the use of different contextual information and efficient, in terms of access delays, in controlling access to resources with divergent levels of sensitivity. The main contribution of this thesis is the proposal of the Context-Risk-Aware Access Control (CRAAC) model. CRAAC achieves fine-grained access control based upon the risk level in the underlying access environment and/or the sensitivity level of the requested resource object. CRAAC makes new contributions to the access control field, those include 1) introducing the concept of level of assurance based access control, 2) providing a method to convert the contextual attributes values into the corresponding level of assurance, 3) Proposing two methods to aggregate the set of level of assurance into one requester level of assurance, 4) supporting four modes of working each suits a different application context and/or access control requirements, 5) a comprehensive access control architecture that supports the CRAAC four modes of working, and 6) an evaluation of the CRAAC performance at runtime.
134

"Construção de aplicações de captura e acesso baseada em recorrência de funcionalidades" / "Building capture and access applications based on recurrence of funcionalities"

Renan Gonçalves Cattelan 19 April 2004 (has links)
Aplicações de captura e acesso exploram o paradigma de computação ubíqua --- que consiste em popular o ambiente com aplicações e dispositivos computacionais a fim de auxiliar transparentemente as pessoas na realização de suas atividades --- para dar apoio à captura automática de informação em experiências ``ao vivo' e à correspondente geração de documentos passíveis de armazenamento, recuperação, visualização e extensão ao longo do tempo. Devido à sua natureza distribuída, à heterogeneidade dos dispositivos computacionais envolvidos e à diversidade nas funcionalidades providas, essas aplicações são difíceis de se construir e requerem infra-estruturas e serviços de software que auxiliem o desenvolvedor nessa tarefa. Este trabalho investiga a construção e o uso de aplicações de captura e acesso por meio do desenvolvimento da xINCA, uma infra-estrutura estendida baseada em componentes de software reutilizáveis que englobam as funcionalidades recorrentes nessa classe de aplicações. A xINCA é uma extensão da infra-estrutura INCA --- uma infra-estrutura de baixo nível que provê abstrações de comunicação para aplicações de captura e acesso. Complementares, as infra-estruturas INCA e xINCA provêem um modelo simplificado para o desenvolvimento de aplicações de captura e acesso, considerando aspectos de projeto, implementação e reuso. Associada ao modelo de armazenamento do serviço StRES, a xINCA tem ainda papel na estruturação da informação capturada com o uso de XML e tecnologias correlatas. / Capture and access applications explore the ubiquitous computing paradigm --- that basically consists on populating the environment with computational devices and applications to transparently assist people on their activities --- to support the automatic capture of information on live experiences and generate corresponding documents that can be further stored, retrieved, visualized and extended. Due to their distributed nature, heterogeneity of involved devices and variety of provided functionalities, capture and access applications are hard to build and require software infrastructures and services that help the developer out on his task. This work investigates the building and use of capture and access applications through the development of xINCA, a component-based software infrastructure comprising the most common func-tio-na-li-ties present in such a class of applications. xINCA is an extension of INCA --- a low-level infrastructure that provides communication abstractions for capture and access applications. Complementary, INCA and xINCA provide a simplified model for the development of capture and access applications, concerning design, implementation and reuse aspects. Allied with the StRES storage model, xINCA also plays an important role on the structuring of captured information by using XML and corresponding technologies.
135

Ansiktsigenkänning för närvarohantering i skolan : Möjligheter och utmaningar utifrån ett användarperspektiv / Face Recognition for Attendance Management in Schools : Opportunities and Challenges From a User Perspective

Holmqvist, Sebastian January 2019 (has links)
I takt med att samhället i stort digitaliseras i hisnande fart kommer även fler och fler lösningar på hur teknik kan hjälpa elever och lärare i den svenska skolan. Internet of Things är på uppgång och nya tekniker för ansiktsigenkänning och databehandling öppnar upp för olika automatiseringsmöjligheter. Syftet med denna rapport är att undersöka användarnas upplevelse av ansiktsigenkänning för närvarohantering i skolan. Lärarnas administrativa börda växer och mycket lektionstid går åt till just närvarotagning, därför hoppas man kunna effektivisera lektionerna och skolan i stort med hjälp av ny teknik. Denna kvalitativa undersökning som görs i samarbete med RISE Research Institutes of Sweden undersöker upplevelsen av ansiktsigenkänningsteknik för närvarotagning och hantering i skolan ur elevernas perspektiv. En klass i en gymnasieskola i Sverige provade under en vecka en prototyp för närvarotagning och fick sedan utvärdera denna i fokusgruppsintervjuer. Resultaten pekar på en positiv inställning till tekniken generellt och att den potentiellt kan ha positiv inverkan på studiemiljön och undervisning. Det visar sig att design och interaktion spelar en viktig roll kring synen på tekniken, och denna studie ämnar ge en helhetsbild av hur elever på ett tekniskt gymnasium upplever tekniken. Undersökningen visar på designutmaningar och öppnar upp för vidare studier i exakt hur ansiktsigenkänningsteknik kan och bör användas i skolmiljö ur ett användarperspektiv. Här ges en grundläggande bild av hur elever upplever ansiktsigenkänningsteknik i skolan och undersökningen bidrar till att stärka arbetet mot en digitaliserad skola. / As society as a whole is digitized in breathtaking speed, more and more solutions to how technology can help students and teachers in the Swedish school system emerge. The Internet of Things is on the rise and new techniques for facial recognition and data processing open up for various automation possibilities. The purpose of this report is to examine the users' experience of facial recognition for attendance management in school. The teachers' administrative burden is growing and a lot of time is devoted to attendance, so one hopes to make the classes, and the school as a whole, more efficient with the help of new technology. This qualitative study, conducted in collaboration with RISE Research Institutes of Sweden, examines the experience of facial recognition techniques for attendance and management in school from the pupils' perspective. One class in a high school in Sweden tested a prototype for attendance during one week and then evaluated it in focus group interviews. The results point to a positive attitude towards the technology in general and that it can potentially have a positive impact on the study environment and teaching. It turns out that design and interaction play an important role in the view of the technology, and this study aims to give an overall picture of how students in a Swedish high school experience the technology. The study shows design challenges and opens up for further studies in exactly how facial recognition technology can and should be used in a school environment from a user perspective. Here, a basic picture is given of how students experience facial recognition technology in school and the study helps to strengthen the work towards a digitized school.
136

A Framework of Freehand Gesture Interaction: Techniques, Guidelines, and Applications

Ni, Tao 17 November 2011 (has links)
Freehand gestures have long been considered to potentially deliver natural, intuitive, terse but powerful human-computer interaction techniques. Over years, researchers have been attempting to employ freehand gestures as an alternative input modality to the conventional devices (e.g. keyboard and mouse) in a wide array of application domains, and a huge number of gesture recognition systems and gesture-based interaction techniques have been created in lab. However, a fundamental question remains: is it possible to establish an interaction framework so that we may approach freehand gestural interaction from a systematic perspective, and design coherent and consistent freehand gesture-based human-computer interaction experience? Existing research tends to focus on the technologies that enable the gestural interaction, or on the novel design of gestural interaction techniques for specific tasks and applications. Such "point designs" are claimed to be insufficient, and an existing application-specific design lends very limited insights and guidance to design problems in another application. An interaction framework allows us to move from individual designs to a more holistic approach. The goal of this research is to construct a framework to support a systematic approach for designing freehand gesture-based interactions. Toward this goal our research began with a review and examination of the gesture interaction literature, followed by an analysis of the essential components of an interaction framework. We then proposed and justified the scope of research and the approach we took to construct the interaction framework. We have designed and evaluated (analytically and empirically) gestural interaction techniques for two broad categories of freehand gestures we specified — spatial gestures, and surface gestures. In the design activity, we have discovered and proposed the core design principles and guidelines, and validated them via user studies. Finally, we assessed the ability of the freehand gesture interaction framework we have constructed to help designers create new applications and designs, by putting together a few proof-of-concept examples of a coherent and consistent freehand gesture user interface. / Ph. D.
137

Rural Virginia Middle School Teachers' and Students' Perceptions on the Influence of One-to-one Computers in the Classroom

Schott, Thomas Jerome 03 December 2012 (has links)
Children of the 21st century are digital learners and have various technologies at their fingertips. As a result, classrooms have evolved and school systems are equipping students and teachers with the technological tools that are believed to meet the needs of 21st century learners. However, researchers say there is still a need to examine students\ and teachers' perceptions of, and attitudes about, technology and its use in the classroom (Maninger & Holden, 2009). There has also been a growing interest in knowing if the investment of the technology is having any positive effects in the classroom, what effect technology has on academic progress, and understanding what teachers and students think about the implementation and integration of technology in the classroom as an instructional tool. The purpose of this study was to examine the perceptions of middle school teachers and students, in a select rural Virginia middle school, on the effect that one-to-one computing had on the frequency and type of instruction that is taking place in the core areas of English, math, science, and social studies.  The study also looked at the teachers' and students' perceived effect on the educational performance of individual subgroups. A quantitative analysis was done using an electronic survey, which provided information on the perceived frequency and type of educational activities using one-to-one computers and the perceived effect one-to-one computing had on the educational performance of different subgroups. Questions on the survey were developed by correlating the theoretical ideas of Bloom's taxonomy / Bloom's web 2.0 technology pyramids and then categorizing the questions so the complexity of the questions could be looked at on the range of use chart. The research found, of the students surveyed, 90% of English students, 78% of math students, 75% of science students, and 77% of social studies students found the computers to have a positive effect on their academic performance. Therefore, one major finding of this study was that students' perceptions of the overall effect of one-to-one computers were positive. / Ed. D.
138

On PlaceMark: Collaborative Authoring, Place, and Identity

Schaefer, Matthew R. 21 July 2009 (has links)
Mobile, digital technologies are thought to augment and transcend the limits of our places, yet they raise the issue of what our places are. PlaceMark is a simple, distributed collaborative authoring environment constructed in conjunction with a site-specific writing activity. This system is examined as a cultural probe, investigating how new media students engage in collaborative writing and how they construct place. Findings include that students engage in the activity as if in parallel play (influencing one another implicitly rather than explicitly), that approaching the notion of place through writing may require development (working through issues brought to the place and the exercise), and that students' relationship to place, at least when asked to write about places that may be considered natural, is not characterized by certainty in behavioral framing. / Master of Science
139

Context aware applications in mobile distributed systems /

Simons, Christof. January 2008 (has links)
University, Diss.--Bamberg, 2007.
140

Digital Family Portraits: Support for Aging in Place

Rowan, James Thomas, Jr. 25 August 2005 (has links)
As people age there is an overwhelming desire to remain in the familiar surroundings of the family home, what is called Aging in Place. But inevitable changes that occur in their lives force the aging adults and their families to consider a move to some form of institutional living. Living at a distance from one another, the adult child attempts to maintain peace of mind concerning the well-being of their aging parents but finds it to be a difficult task. I propose to address this problem by first proposing that technology can help minimize the anxieties experienced by the adult child concerning their aging parents well being by appropriately presenting information on the aging parents daily life. This technological design concept does not require that the aging parent input, or for that matter, do anything other than live their lives as they normally live them. Further, this technology provides this information in a manner that is continuously available to the adult child for either opportunistic or planned perusal. As a single instance of the technological design concept proposed above, the Digital Family Portrait embeds well-being related information into an item commonly found in homes, the picture in a picture frame. The Digital Family Portrait was first tested in a wizard-of-oz field trial, then redesigned based on the outcome of this initial field trial coupled with the results of two lab-based studies and a further informal evaluation. The redesigned Digital Family Portrait was built and installed in the home of an adult child while the sensors to drive it were installed in an aging parents home. A field trial of this installation lasting for one year was conducted. The result of this field trial was to find that the Digital Family Portrait was an acceptable means of resolving certain peace of mind issues for the adult child while not raising privacy. It was found to be used in a socially acceptable manner by the adult child while the aging parent to reported feeling less lonely.

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