In this thesis work, a certificate based authentication model supported by mobile devices is provided for ubiquitous computing environments. The model primarily aims to create an infrastructure for controlling and regulating access requests through mobile devices to local resources and services. The model also allows users from different domains to use local resources and services within the scope of agreements between domains. In addition to conceptual description of the model, a real prototype implementation is developed and successful application of the model is demonstrated. Within the prototype implementation, a mobile application is developed for access requests and sensors are used as representative local resources. Sample cases applied on the prototype demonstrate applicability and feasibility of the model.

The increasing ubiquity of networked mobile devices such as cell phones and PDAs has created new opportunities for the transmission and display of multimedia content. However, any mobile device has inherent resource constraints: low network bandwidth, small screen sizes, limited input methods, and low commitment viewing. Mobile systems that provide information display and access thus need to mitigate these various constraints. Despite progress in information retrieval and content recommendation, there has been less focus on issues arising from a network-oriented and mobile perspective. This dissertation investigates a coordinated design approach to networked multimedia on mobile devices, and considers the abovementioned system perspectives. Within the context of accessing news video on mobile devices, the goal is to provide a cognitively palatable stream of videos and a seamless, low-latency user experience. Mixed-initiative---a method whereby intelligent services and users collaborate efficiently to achieve the user's goals, is the cornerstone of the system design and integrates user relevance feedback with a content recommendation engine and a content- and network-aware video buffer prefetching technique. These various components have otherwise been considered independently in other prior system designs. To overcome limited interactivity, a mixed-initiative user interface was used to present a sequence of news video clips to the user, along with operations to vote-up or vote-down a video to indicate its relevance. On-screen gesture equivalents of these operations were also implemented to reduce user interface elements occupying the screen. Semantic relevancy was then improved by extracting and indexing the content of each video clip as text features, and using a Na"ive Bayesian content recommendation strategy that harnessed the user relevance feedback to tailor the subsequent video recommendations. With the system's knowledge of relevant videos, a content-aware video buffer prefetching scheme was then integrated, using the abovementioned feedback to lower the user perceived latency on the client-end. As an information retrieval system consists of many interacting components, a client-server video streaming model is first developed for clarity and simplicity. Using a CNN news video clip database, experiments were then conducted using this model to simulate user scenarios. As the aim of improving semantic relevancy sometimes opposes user interface tools for interactivity and user perceived latency, a quantitative evaluation was done to observe the tradeoffs between bandwidth, semantic relevance, and user perceived latency. Performance tradeoffs involving semantic relevancy and user perceived latency were then predicted. In addition, complementary human user subjective tests are conducted with actual mobile phone hardware running on the Google Android platform. These experiments suggest that a mixed-initiative approach is helpful for recommending news video content on a mobile device for overcoming the mobile limitations of user interface tools for interactivity and client-end perceived latency. Users desired interactivity and responsiveness while viewing videos, and were willing to sacrifice some content relevancy in order gain lower perceived latency. Recommended future work includes expanding the content recommendation to incorporate viewing data from a large population, and the creation of a global hybrid content-based and collaborative filtering algorithm for better results. Also, based on existing user behaviour, users were reluctant to provide more input than necessary. Additional user experiments can be designed to quantify user attention and interest during video watching on a mobile device, and for better definition and incorporation of implicit user feedback.

Innovative mobile Endgeräte und Applikationen durchdringen nicht mehr nur das Berufs- und Privatleben, sondern finden auch zunehmend Einsatz in der Aus- und Fortbildung. Dies gilt sowohl in Hinblick auf das „Lifelong Learning“ als auch in der schulischen und universitären Ausbildung. Neue Regelungen zu Bachelor- und Masterprogrammen, Lehrformen wie Gruppenarbeiten und die zunehmende Mobilität der Studierenden verlangen nach neuen Lernmedien und Lehrkonzepten, die es ermöglichen, bisherige Lehrlaufzeiten im Studium sinnvoll zu nutzen. (...)

Augmented Reality (AR) is a fast-emerging technology and it has been applied in many fields e.g. education, health, entertainment, gaming and tracking systems in logistics. AR technology combines the virtual world with the reality by superimposing digital information onto the physical world. This study evaluates the usability of the AR in industrial environment focusing on effectiveness, efficiency, and user acceptance in comparison to other instructional medium e.g. paper-based instructions or manuals. An AR prototype was developed to be used in the usability evaluation. To evaluate the AR application in the field of industry an experiment was conducted. To get the user experience and acceptance questionnaires and interviews were used involving real assembly workers where they used the AR prototype. The results of the study show that when using AR as assistance in the assembly assurance process, the number of faults and task completion time were reduced significantly compared to the traditional methods. Also, the users had a positive attitude and a high level of satisfaction when using AR.

De nos jours, le maintien de l'asepsie dans la salle d'opération est vital pour la limitation de la transmission d'infections nosocomiales au patient lors de l'opération. Des mesures d'asepsie drastiques ont pour but de préserver la zone stérile de tout agent infectieux.Elles interdisent actuellement au chirurgien d'interagir avec les équipements non-stériles du bloc.Le chirurgien opérant souhaiterait cependant disposer d'un contrôle direct sur certains équipements spécifiques du bloc dans des situations données sans enfreindre ces mesures.Les travaux présentés dans cette thèse concernent le développement d'une Interface Homme-Machine permettant la commande gestuelle sans contact, et donc sans transmission d'agents infectieux, de tels équipements.Dans la continuité des travaux existants dans la littérature, une chaîne de traitement basée sur des techniques de vision informatique et un prototype de caméra portée par l'utilisateur ont ainsi été développés pour atteindre ces objectifs. Ce document présente les études comparatives menées sur des algorithmes issus de la littérature afin de sélectionner les plus aptes à être employés dans la chaîne logicielle. Un descripteur géométrique dédié aux mains est introduit, et des approches coopératives sont investiguées sur les étapes de localisation de la main et de classification de la posture prise.Les performances de la chaîne de traitement ainsi créée sont évaluées dans différentes situations à l'aide de bases d'images et de vidéos extensives acquises dans des conditions proches de celles du bloc opératoire, ainsi que sur des images synthétiques réalisées sur un modèle virtuel de main créé ad hoc.Un démonstrateur composé de la chaîne de traitement développée et d'un prototype de caméra frontale permet, associé à une simulation de bras-support d'éclairage opératoire, d'illustrer les possibilités ouvertes par le système développé au cours de cette thèse. / Asepsis preservation in operating rooms is nowadays compulsory for avoiding the spread of hospital-acquired diseases to patients during surgeries. Drastic asepsis measures aim at preserving the sterile area of the operating room from infective agents.These measures forbid surgeons from interacting with non-sterile devices. Surgeons wish nonetheless having direct control over some of these devices.The works presented in this thesis relate to the development of a Human-Computer Interface enabling remote, hence without transmission of infective agents, non-contact control over such devices.Following on from previous authors' works in the literature, an image processing chain based on computer vision techniques and a wearable camera prototype have been developed in order to achieve these goals.This document presents the comparative studies led with algorithms issued from the literature with the aim of selecting the most suitable for using in the processing chain. A dedicated geometry-based hand descriptor is introduced, and cooperative approaches are investigated in relation with the hand localization and posture classification steps.The performance achieved by the processing chain in various situations are quantified using extensive picture and video databases acquired in conditions close to those of the operating room. Synthetic pictures created using an ad hoc virtual model of the hand are used as well for this evaluation.A demonstrator composed of the developed processing chain, a wearable camera prototype and a surgical lighting arm simulator enables the illustration of the possiblities offered by the system developed during this thesis.

Com a contínua propagação dos dispositivos móveis, uma área editorial pode estar sujeita a ficar defasada e não seguir os avanços da tecnologia – os catálogos de museus, que foram sempre uma categoria distinta de publicação. Neste momento um crescente número de instituições procura tirar partido da revolução dos dispositivos móveis, já que os usuários estão cada vez mais em sintonia com o que a tecnologia pode oferecer. Já não é suficiente publicar imagens de um objeto, o que gera um desafio para a instituição – como preservar a sua identidade tirando partido desta nova tecnologia? Em um tempo em que está se tornando cada vez mais fácil a auto-publicação no mundo digital, como testemunhado pelo conteúdo das redes sociais, a ascensão dos e-books e a descentralização de conteúdo, quais elementos se aplicam especificamente aos aplicativos de museus neste espaço? Este trabalho apresenta uma seleção de sugestões apontadas aos aplicativos para que possam aproveitar as tecnologias emergentes e ir além das versões impressas, sem perder o contato com o artista, o espaço e a instituição. / As the spread of mobile devices continues, one area of publishing risks being left behind the technology. Museum catalogues have always been a distinct category of publishing, and were slow to be successfully and widely shifted to a digital format. Now, a growing number of institutions are looking to take advantage of the mobile revolution, the mobile user is also becoming more attuned to what their technology can offer. Simply rendering a publication or object in two-dimensional digital format is no longer sufficient throwing a challenge to the institution – how to preserve their identity and character. In a time when it is becoming easier and easier to self-publish into the digital realm; as witnessed by social content, the rise of the e-book and the decentralization of content, what elements concern specifically to museum catalogues in this space? This work presents a selection suggestions applicable specifically to museum catalogues so they can leverage the emerging technologies and go beyond the printed versions, without losing touch with the artist, the exhibition and the institution. Furthermore, there is an indication of the best multimedia elements that can be added to these catalogues in order to aggregate content and extend the visitor experience.

INTRODUCTION: While mobile device use by physicians increases, there is an increased risk that errors committed while using mobile devices can lead to harm. This mixed-method study evaluates the effects of screen size on clinical users’ perceptions of medical application usability and safety when interfacing to critical patient information. In this research, two mobile devices are examined: iPhone® and the iPad®. METHOD: Eleven physicians and one nurse practitioner participated in a chart-review simulation using an app that was an end-point to an electronic health record. Screen-recording, video-recording and a think-aloud protocol were used to gather data during the simulation. Additionally, participants completed Likert-based questionnaires and engaged in semi-structured interviews. RESULTS: A total of 105 usability, usefulness and safety problems were recorded and analysed. A strong preference was found for the larger screen when reviewing patient data due to the large quantity of data and the increased display size. The smaller device was preferred due to the devices portability when participants needed to remain informed when they were away from the point of care. CONCLUSION: There is an association between screen size and the perceived safety of the handheld device. The iPad was perceived to be safer to use in clinical practice. Participants preferred the iPad® because of the larger size, not because they thought it was safer or easier to use. The iPhone® was preferred for its portability and its usefulness was perceived to increase with greater distance from the point of care. / Graduate

abstract: With the rise of mobile technology, the personal lives and sensitive information of everyday citizens are carried about without a thought to the risks involved. Despite this high possibility of harm, many fail to use simple security to protect themselves because they feel the benefits of securing their devices do not outweigh the cost to usability. The main issue is that beyond initial authentication, sessions are maintained using optional timeout mechanisms where a session will end if a user is inactive for a period of time. This interruption-based form of continuous authentication requires constant user intervention leading to frustration, which discourages its use. No solution currently exists that provides an implementation beyond the insecure and low usability of simple timeout and re-authentication. This work identifies the flaws of current mobile authentication techniques and provides a new solution that is not limiting to the user, has a system for secure, active continuous authentication, and increases the usability and security over current methods. / Dissertation/Thesis / Masters Thesis Computer Science 2014

Com a contínua propagação dos dispositivos móveis, uma área editorial pode estar sujeita a ficar defasada e não seguir os avanços da tecnologia – os catálogos de museus, que foram sempre uma categoria distinta de publicação. Neste momento um crescente número de instituições procura tirar partido da revolução dos dispositivos móveis, já que os usuários estão cada vez mais em sintonia com o que a tecnologia pode oferecer. Já não é suficiente publicar imagens de um objeto, o que gera um desafio para a instituição – como preservar a sua identidade tirando partido desta nova tecnologia? Em um tempo em que está se tornando cada vez mais fácil a auto-publicação no mundo digital, como testemunhado pelo conteúdo das redes sociais, a ascensão dos e-books e a descentralização de conteúdo, quais elementos se aplicam especificamente aos aplicativos de museus neste espaço? Este trabalho apresenta uma seleção de sugestões apontadas aos aplicativos para que possam aproveitar as tecnologias emergentes e ir além das versões impressas, sem perder o contato com o artista, o espaço e a instituição. / As the spread of mobile devices continues, one area of publishing risks being left behind the technology. Museum catalogues have always been a distinct category of publishing, and were slow to be successfully and widely shifted to a digital format. Now, a growing number of institutions are looking to take advantage of the mobile revolution, the mobile user is also becoming more attuned to what their technology can offer. Simply rendering a publication or object in two-dimensional digital format is no longer sufficient throwing a challenge to the institution – how to preserve their identity and character. In a time when it is becoming easier and easier to self-publish into the digital realm; as witnessed by social content, the rise of the e-book and the decentralization of content, what elements concern specifically to museum catalogues in this space? This work presents a selection suggestions applicable specifically to museum catalogues so they can leverage the emerging technologies and go beyond the printed versions, without losing touch with the artist, the exhibition and the institution. Furthermore, there is an indication of the best multimedia elements that can be added to these catalogues in order to aggregate content and extend the visitor experience.

Com a contínua propagação dos dispositivos móveis, uma área editorial pode estar sujeita a ficar defasada e não seguir os avanços da tecnologia – os catálogos de museus, que foram sempre uma categoria distinta de publicação. Neste momento um crescente número de instituições procura tirar partido da revolução dos dispositivos móveis, já que os usuários estão cada vez mais em sintonia com o que a tecnologia pode oferecer. Já não é suficiente publicar imagens de um objeto, o que gera um desafio para a instituição – como preservar a sua identidade tirando partido desta nova tecnologia? Em um tempo em que está se tornando cada vez mais fácil a auto-publicação no mundo digital, como testemunhado pelo conteúdo das redes sociais, a ascensão dos e-books e a descentralização de conteúdo, quais elementos se aplicam especificamente aos aplicativos de museus neste espaço? Este trabalho apresenta uma seleção de sugestões apontadas aos aplicativos para que possam aproveitar as tecnologias emergentes e ir além das versões impressas, sem perder o contato com o artista, o espaço e a instituição. / As the spread of mobile devices continues, one area of publishing risks being left behind the technology. Museum catalogues have always been a distinct category of publishing, and were slow to be successfully and widely shifted to a digital format. Now, a growing number of institutions are looking to take advantage of the mobile revolution, the mobile user is also becoming more attuned to what their technology can offer. Simply rendering a publication or object in two-dimensional digital format is no longer sufficient throwing a challenge to the institution – how to preserve their identity and character. In a time when it is becoming easier and easier to self-publish into the digital realm; as witnessed by social content, the rise of the e-book and the decentralization of content, what elements concern specifically to museum catalogues in this space? This work presents a selection suggestions applicable specifically to museum catalogues so they can leverage the emerging technologies and go beyond the printed versions, without losing touch with the artist, the exhibition and the institution. Furthermore, there is an indication of the best multimedia elements that can be added to these catalogues in order to aggregate content and extend the visitor experience.