Since the introduction of graphical user interfaces (GUI), input control devices have become an integral part of desktop computing. When interfacing with GUIs, these input control devices have become the human's primary means of communicating with the computer. Although there have been a number of experiments conducted on pointing devices for desktop machine, there is little research on pointing devices for wearable computer technology. This is surprising because pointing devices are a major component of a wearable computer system, allowing the wearer to select and manipulate objects on the screen. The design of these pointing devices will have a major impact on the ease with which the operator can interact with information being displayed (Card, English, and Burr, 1978). As a result, this research is the first in a series to investigate design considerations for pointing devices and visual displays that will support wearable computer users. Twenty soldiers participated in an experiment using target acquisition software with five pointing devices and two visual displays. The findings of the research strongly support the use of a relative mode-pointing device with rotational characteristics (i.e. trackball or thumbwheel) over other designs. Furthermore, the results also suggest that there is little difference between pointing devices operated with the thumb and index finger for target acquisition tasks. This study has also showed that there were little differences in pointing and homing time for pointing devices across the two visual displays. Finally, the study demonstrated that the Fitts' law model could be applied to hand-operated pointing devices for wearable computers. This is important because it allows the future development of pointing devices to be compared with the devices tested in this research using the Fitts' Law Index of Performance calculations. / Master of Science

La loi de Fitts, qui relie le temps de mouvement MT dans une tache de pointage aux dimensions de la cible visée D et W est usuellement exprimée à partir d’une imitation de la formule de la capacité de Shannon MT = a + b log 2 (1 + D/W). Toutefois, l’analyse actuelle est insatisfaisante: elle provient d’une simple analogie entre la tache de pointage et la transmission d’un signal sur un canal bruité sans qu’il n’y ait de modèle explicite de communication.Je développe d’abord un modèle de transmission pour le pointage, où l’indice de difficulté ID = log 2 (1 + D/W) s’exprime aussi bien comme une entropie de source et une capacité de canal, permettant ainsi de réconcilier dans un premier temps l’approche de Fitts avec la théorie de l’information de Shannon. Ce modèle est ensuite exploité pour analyser des données de pointage récoltées lors d’expérimentations contrôlées mais aussi en conditions d’utilisations réelles.Je développe ensuite un second modèle, focalisé autour de la forte variabilité caractéristique du mouvement humain et qui prend en compte la forte diversité des mécanismes de contrôle du mouvement: avec ou sans voie de retour, par intermittence ou de manière continue. À partir d’une chronométrie de la variance positionnelle, évaluée à partir d’un ensemble de trajectoires, on remarque que le mouvement peut-être découpé en deux phases: une première où la variance augmente et une grande partie de la distance à couvrir est parcourue, est suivie d’une deuxième au cours de laquelle la variance diminue pour satisfaire les contraintes de précision requises par la tache.Dans la deuxième phase, le problème du pointage peut-être ramené à un problème de communication à la Shannon, où l’information est transmise d’une“source” (variance à la fin de la première phase) à une “destination” (extrémité du membre) à travers un canal Gaussien avec la présence d’une voie de retour.Je montre que la solution optimale à ce problème de transmission revient à considérer un schéma proposé par Elias. Je montre que la variance peut décroitre au mieux exponentiellement au cours de la deuxième phase, et que c’est ce résultat qui implique directement la loi de Fitts. / Fitts’ law, which relates movement time MTin a pointing task to the target’s dimensions D and Wis usually expressed by mimicking Shannon’s capacityformula MT = a + b log 2 (1 + D/W). Yet, the currentlyreceived analysis is incomplete and unsatisfactory: itstems from a vague analogy and there is no explicitcommunication model for pointing.I first develop a transmission model for pointing taskswhere the index of difficulty ID = log 2 (1 + D/W) isthe expression of both a source entropy and a chan-nel capacity, thereby reconciling Shannon’s informa-tion theory with Fitts’ law. This model is then levera-ged to analyze pointing data gathered from controlledexperiments but also from field studies.I then develop a second model which builds on thevariability of human movements and accounts for thetremendous diversity displayed by movement control:with of without feedback, intermittent or continuous.From a chronometry of the positional variance, eva-luated from a set of trajectories, it is observed thatmovement can be separated into two phases: a firstwhere the variance increases over time and wheremost of the distance to the target is covered, follo-wed by a second phase where the variance decreasesuntil it satisfies accuracy constraints. During this se-cond phase, the problem of aiming can be reduced toa Shannon-like communication problem where infor-mation is transmitted from a “source” (variance at theend of the first phase), to a “destination” (the limb ex-tremity) over a “channel” perturbed by Gaussian noisewith a feedback link. I show that the optimal solution tothis transmission problem amounts to a scheme firstsuggested by Elias. I show that the variance can de-crease at best exponentially during the second phase,and that this result induces Fitts’ law.

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La sélection de cibles en mouvement est une tâche courante et complexe dans l'interaction homme-machine (IHM) en général et en particulier dans le domaine de la réalité virtuelle (RV). La prédiction de l'action est une solution intégrale pour aborder les problèmes liés à l'interaction. Cependant, les techniques actuelles de prédiction sont basées sur le suivi continu des actions de l'utilisateur sans prendre en compte la possibilité que les actions d'atteinte d'une cible puissent avoir une composante importante préprogrammée—cette théorie est appelé la théorie du contrôle préprogrammé.En se basant sur la théorie du contrôle préprogrammé, cette thèse explore la possibilité de prédire les actions, avant leur exécution, de sélection d'objets en mouvement. Plus spécifiquement, trois niveaux de prédiction d'action sont étudiés : 1) la performance des actions, mesurée par le temps de mouvement (TM) nécessaire pour atteindre une cible, 2) la difficulté prospective (DP), qui représente la difficulté subjective de la tâche estimée avant son exécution, 3) l'intention de l'utilisateur, qui indique la cible visée par l'utilisateur.Dans le cadre de cette thèse, des modèles de prédiction d'intention sont développés à l'aide des arbres de décision ainsi que des fonctions de classement—ces modèles sont évalués dans deux expériences en RV. Des modèles 1-D et 2-D de DP pour des cibles en mouvement basés sur la loi de Fitts sont développés et évalués dans une expérience en ligne. Enfin, des modèles de TM avec les mêmes caractéristiques structurelles des modèles de DP sont évaluées dans une expérience 3-D en RV. / Selection of moving targets is a common, yet complex task in human–computer interaction (HCI), and more specifically in virtual reality (VR). Action prediction has proven to be the most comprehensive enhancement to address moving-target selection challenges. Current predictive techniques, however, heavily rely on continuous tracking of user actions, without considering the possibility that target-reaching actions may have a dominant pre-programmed component—this theory is known as the pre-programmed control theory.Thus, based on the pre-programmed control theory, this research explores the possibility of predicting moving-target selection prior to action execution. Specifically, three levels of action prediction are investigated: 1) action performance measured as the movement time (MT) required to reach a target, 2) prospective difficulty (PD), i.e., subjective assessments made prior to action execution; and 3) intention, i.e., the target that the user plans to reach.In this dissertation, intention prediction models are developed using decision trees and scoring functions—these models are evaluated in two VR studies. PD models for 1-D, and 2-D moving- target selection tasks are developed based on Fitts' Law, and evaluated in an online experiment. Finally, MT models with the same structural form of the aforementioned PD models are evaluated in a 3-D moving-target selection experiment deployed in VR.

Le génie logiciel a pour but de créer des outils logiciels qui permettent de résoudre des problèmes particuliers d’une façon facile et efficace. À cet égard, l’ingénierie dirigée par les modèles (IDM), facilite la création d’outils logiciels, en modélisant et transformant systématiquement des modèles. À cette fin, l’IDM s’appuie sur des workbenches de langage : des environnements de développement intégré (IDE) pour modéliser des langages, concevoir des modèles, les exécuter et les vérifier. Mais l’utilisation des outils est loin d’être efficace. Les activités de l’IDM typiques, telles que la création d’un langage de domaine dédié ou créer une transformation de modèles, sont des activités complexes qui exigent des opérations souvent répétitives. Par conséquent, le temps de développement augmentate inutilement. Le but de ce mémoire est de proposer une approche qui augmente la productivité des modélisateurs dans leurs activités quotidiennes en automatisant le plus possible les tâches à faire dans les outils IDM. Je propose une solution utilisant l’IDM où l’utilisateur définit un flux de travail qui peut être paramétré lors de l’exécution. Cette solution est implémentée dans un IDE pour la modélisation graphique. À l’aide de deux évaluations empiriques, je montre que la productivité des utilisateurs est augmentée et amééliorée. / Software engineering aims to create software tools that allow people to solve particular problems in an easy and efficient way. In this regard, Model-driven engineering (MDE) enables to generate software tools, by systematically modeling and transforming models. In order to do this, MDE relies on language workbenches: Integrated Development Environment (IDE) for engineering modeling languages, designing models executing them and verifying them. However, the usability of these tools is far from efficient. Common MDE activities, such as creating a domain-specific language or developing a model transformation, are nontrivial and often require repetitive tasks. This results in unnecessary risings of development time. The goal of this thesis is to increase the productivity of modelers in their daily activities by automating the tasks performed in current MDE tools. I propose an MDE-based solution where the user defines a reusable workflow that can be parameterized at run-time and executed. This solution is implemented in an IDE for graphical modeling. I also performed two empirical evaluations in which the users’ productivity is improved.

No description available.

As increasingly large displays are integrated into personal workspaces, mouse-based interaction becomes more problematic. Users must repeatedly "clutch" the mouse for long distance movements [61]. The visibility of the cursor is also problematic in large screens, since the percentage of the screen space that the cursor takes from the whole display gets smaller. We test multi-scale approaches to mouse interaction that utilize dynamic speed and size techniques to grow the cursor larger and faster for long movements. Using Fitts' Law methods, we experimentally compare different implementations to optimize the mouse design for large displays and to test how they scale to large displays. We also compare them to techniques that integrate absolute pointing with head tracking. Results indicate that with some implementation level modifications the mouse device can scale well up to even a 100 megapixel display with lower mean movement times as compared to integrating absolute pointing techniques to mouse input while maintaining fast performance of the typical mouse configuration on small screens for short distance movements. Designs that have multiple acceleration levels and 4x maximum acceleration reduced average number of clutching to less than one per task in a 100 megapixel display. Dynamic size cursors statistically improve pointing performance. Results also indicated that dynamic speed transitions should be as smooth as possible without steps of more than 2x increase in speed. / Master of Science

Neste estudo foi analisado o efeito de distância, velocidade, tamanhos do disco e do alvo, e massas do disco e da manopla, sobre o desempenho motor em movimentos requisitando rapidez e precisão. Para tanto, foram analisadas as características cinemáticas da tarefa de projetar um disco a um alvo com movimento de contato balístico, empunhando uma manopla. Os movimentos foram desempenhados sobre uma base plana e filmados com câmera optoeletrônica de alta freqüência. O estudo foi conduzido em seis experimentos com um grupo único de participantes. Os resultados indicaram que os modelos de controle motor que têm sido empregados para analisar a relação velocidade-precisão em tarefas mais simples não foram apropriados para explicar o comportamento da tarefa utilizada. O controle motor na tarefa demonstrou ser dinâmico e flexível, frente às diferentes restrições de movimento. As seguintes estratégias de controle foram sugeridas na explicação dos resultados: sincronização da maior velocidade e do instante de contato manopla-disco, manutenção na proporção entre as fases aceleração-desaceleração, maior inércia e menor impacto para aumentar a estabilidade de movimento, e o controle da velocidade e da precisão em dimensões independentes. A análise das ações articulares demonstrou as particularidades das estratégias utilizadas pelo sistema no movimento em função das variáveis manipuladas. Em conjunto, esta seqüência de experimentos permitiu uma compreensão mais ampla das estratégias de controle motor empregadas em movimentos com alta demanda de velocidade e de precisão / In this study it was analyzed the effect of distance, velocity, disc and target width, disc and manipulandum mass, over motor control of a rapid and accurate movement. For such, it was analyzed the kinematic characteristics of the task of launching a disc to a target using a ballistic movement, performed with a manipulandum. Movements were performed on a flat surface and filmed with a high frequency optoelectronic camera. The study was conducted through six experiments with a single group of participants. Analysis of results indicated that models of motor control that has been used to analyze speed-accuracy tradeoff in simpler tasks were not appropriate to explain the observed behavior in the task used. Motor control in the task showed to be dynamic and flexible, regarding the several constraints manipulated. The follow strategies of control were suggested to explain the results: synchronization of the peak velocity and the instant of disc-manipulandum contact, maintenance of the proportion between the acceleration-deceleration phases, greater inertia and minor impact to increase movement stability, and control of velocity and accuracy of independent dimensions. The prediction of Analysis of joint actions showed the particularities of the strategies used by the system on movement as a function of the manipulated variables. Together, this study sequence of experiments allowed for a deeper comprehension of the control strategies used in the control of rapid and accurate movements

Auditory graphs and active point estimation provide an inexpensive, accessible alternative for low vision and blind K-12 students using number lines and coordinate graphs. In the first phase of this research program, a series of four psychophysics studies demonstrated an interactive auditory number line that enables blind, low vision, and sighted people to find small targets with a laptop, headphones, and a mouse or a keyboard. The Fitts' Law studies showed that, given appropriate auditory feedback, blind people can use a mouse. In addition, auditory feedback can generate target response patterns similar to when people use visual feedback. Phase two introduced SQUARE, a novel method for building accessible alternatives to existing education technologies. The standards-driven and teacher-directed approach generated 17 graphing standards for sixth grade mathematics, all of which emphasized point estimation. It also showed that how only few basic behavioral components are necessary for these graphing problems. The third phase evaluated active point estimation tools in terms of training, classroom situations, and a testing situation. This work shows that students can learn to graph in K-12 environments, regardless of their visual impairment. It also provides several technologies used for graphing, and methods to further develop education accessibility research.

This thesis assesses the speed of adaptation and adoption of computing systems from an adult first-time user perspective in South Africa, with the aim of determining if it could ultimately lead to the reduction of the existing digital gap. As is evident from the social, educational, and economical gap for some observers, the reality of the existence of the digital gap in South Africa is undeniable. Constant non-targeted progress is made toward addressing imbalances, which seem to be more visible as the number of constant and permanent users is visibly increasing. These observed phenomena are mostly noticed amongst urban, educated, younger, middle-class citizens. The forgotten “missing middle” are left to fend for themselves. These are people who are still outside the digital drive the world is experiencing based on their schooling grade, geographical location, income level, and age. They were not in school when computer literacy was introduced, and they were too poor to teach themselves how to use a computer, too remote to observe the digital drive, and too old to learn from their peers. As citizens, their welfare matters, and when assessing the penetration of ICT in the country, their numbers also matter. One cannot ignore their presence and the difficulties and frustration that they experience when coming into contact with a computing system for the first time. The researcher is of the view that the presence of a computing system may not simply translate to the closure of the digital gap. In other words, people may gain access to a computer, but without computing usability skills or Internet connectivity it may not add value to their daily activities. Closing the digital gap in South Africa can be seen as political propaganda, but the reality is, how do we measure and assess it? It comes down to users, and in this particular case, attention is turned to the “missing middle”, here referred to as the adult first-time user. This is simply someone who is over the age of 18 years, lives in a rural community in South Africa, never completed school, and is using a computer for the first time. The researcher used a handheld tablet system as a tool to assess the participants’ adequacy in terms of the rate at which they complete tasks by developing mathematical equations which were placed together within an assessment metric that was later used to determine user proficiency, as well as their adaptation and user experience in order to determine if the participant can later adopt the device and take advantage of it. By so doing, the metric will comprise variables such as the user movement time, task completion success rate, task completion speed, user satisfaction, user reaction time, user completion rate per activity, time-based efficiency, and the assessment of the level of frustration any adult first-time user may experience while interacting with the system for the first time. The term “digital gap” may not be new to the ICT sphere, but no one has taken the step towards assessing it. The digital gap is no longer the absence of computing systems in many communities but rather the presence of inadequate user experience, which has not been properly measured and documented. The user experience metric (UXM) that was developed in this study provided the researcher with the opportunity to reassess the issue of systems adaptation, adoption, and usability by adult first-time users. This research is particularly driven by sound interaction design principles, user adaptation, and usability and user experience / Ph. D. (Information Systems) / School of Computing