Nous percevons mieux notre corps et notre environnement si l’on tient compte de plusieurs sources sensorielles en même temps. Mais tous les systèmes sensoriels déclinent progressivement au cours du vieillissement. Cette thèse a contribué à mieux comprendre comment les perceptions multisensorielles et les réseaux cérébraux qui les sous-tendent sont modifiés chez la personne âgée. Ce travail souligne l’existence d’une repondération des informations sensorielles et une facilitation générale des processus d’interaction entre les sens pour optimiser la perception des mouvements du corps ou la perception de textures dès 65 ans. Au niveau cérébral, l'effondrement des processus inhibiteurs avec l'âge entrainerait une moins bonne sélection des réseaux et expliquerait les troubles perceptifs. Néanmoins, les personnes âgées pourraient bénéficier d’un recrutement cérébral moins spécifique pour surmonter au moins partiellement ces déclins sensoriels. / We can better perceive our body and our environment if we take into account several sensory sources at the same time. However, all sensory systems gradually decline with aging. This thesis contributes to a better understanding of how multisensory perceptions and the underlying brain networks are modified in the elderly. This work highlights both a reweighting of sensory information and a general facilitation of interaction processes between the senses to optimize the perception of body movements or the perception of textures as soon of 65 years old. At the brain level, the break-down of inhibitory processes with age would lead to a poorer selection of networks and would explain perceptual disorders. Nevertheless, older people could benefit from less specific brain recruitment to at least partially compensate these sensory declines.

The explorative scanning movements of the hands have been compared to those of the eyes. The visual process is known to be composed of alternating phases of saccadic eye movements and fixation pauses. Descriptive results suggest that during the haptic exploration of objects short movement pauses occur as well.The goal of the present study was to detect these \"explorative stops\"(ES) during one-handed and two-handed haptic explorations of various objects and patterns, and to measure their duration. Additionally, the associations between the following variables were analyzed:(a) between mean exploration time and duration of ES, (b) between certain stimulus features and ES frequency, and (c) the duration of ES during the course of exploration.:Introduction; Materials and methods; Results; Discussion

<p>  </p> <p>In order to comprehend complex and abstract phenomena, students must partake in the process of learning by integrating complex and invisible components without ever physically encountering or manipulating such components. Prior knowledge and experiences will influence the way students assimilate and model new experiences and knowledge. If prior knowledge possesses a degree of non-normative conceptions, students' understanding of abstract phenomena may diverge dramatically from accepted scientific explanations. Embodied cognition proposes that learning about natural phenomena can develop from information gained via interactions between the body and the physical environment. Multimodal experiences can shape students' conceptual understanding of abstract phenomena.</p> <p>Incorporating technology tools to explore science concepts is a trend utilized to give high-quality education. The use of physical and virtual manipulation tools in science instruction has favored the improvement of modeling science phenomena in general. Visuohaptic simulations are also learning manipulatives that blend physical and virtual manipulation affordances as a unison experience. </p> <p>The current dissertation proposed the implementation of a learning experience where students engage in experimentation with a visuo-haptic simulation to explore and model reaction forces on truss structures. The study examined undergraduate students’ conceptual understanding, graphical representations, and the modeling refinement process of reaction forces on truss structures before, during, and after engaging with visuo-haptic simulation on truss structures using different modalities. A design-based research methodology was implemented to design, explore, and refine a learning experience with a visuo-haptic simulation of truss structures through two research phases. The learning experience occurred as a laboratory activity in a statics course at a Midwest university.</p> <p>The first phase of this dissertation investigated students' conceptual understanding and graphical representations of reactive forces on a complex truss structure by interacting with a visuo-haptic simulation of truss structures. Students participated in two treatment groups: visuo-haptic exposure and visual-only exposure. The results of the first phase suggested that students that engaged with the visuo-haptic simulation using different modalities improved their conceptual understanding of truss structures significantly. Moreover, students exposed to haptic feedback significantly improved their graphical representations on tasks where the haptic feedback was involved. </p> <p>The second phase of the current dissertation examined students’ developing models of reactive forces on a truss structure before, during, and after engaging with a visuo-haptic simulation of truss structures. Students participated in two sequential treatment groups: visual to visuo-haptic and haptic to visuo-haptic. The quantitative results suggest that both treatment groups performed significantly better in their model representations after being exposed to the learning experience but show no difference across treatment groups. The qualitative results suggest that the visual to visuo-haptic group interpreted their experiences much more coherently, leading to a more sophisticated version of their model of reaction forces on truss structures. </p>

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Active safety systems that warn automobile drivers of various types of impending collisions have been developed. How these systems alert drivers when integrated, however, is a crucial component to their effectiveness that hinges on the consideration of human factors. Drivers' ability to comprehend multiple alerts presented through a haptic driver seat was investigated in this dissertation. Twenty-four participants, balanced for age and gender, drove an instrumented vehicle on a test-track while haptic alerts (vibrations in the driver seat) were generated. Drivers' ability to transmit the information conveyed by the alerts was investigated through two experiments. The first experiment investigated the effects of increasing the number of potential alerts on drivers' response performance. The second experiment investigated whether presenting haptic alerts through unique versus common locations in the driver seat affects drivers' response performance. Younger drivers (between the ages of 18 and 25 years old) were found to efficiently process the increased information contained in the alerts, while older drivers were not as efficient. However, it is foreseeable that older driver performance decrements may be assuaged when a crash context is provided. A third experiment evaluated the haptic driver seat's ability to alert distracted drivers to an actual crash threat. Drivers that received a haptic seat alert returned their gaze to the forward roadway sooner, removed their foot from the throttle sooner, pressed the brake pedal sooner, and stopped farther away from an inflatable barricade than drivers that did not receive a haptic seat alert. No age or gender effects were found in this experiment. Furthermore, half of the drivers that received the haptic seat alert lifted up on the throttle before returning their eyes to the forward roadway. This suggests these drivers developed an automatic response to the haptic seat alerts through their experience with the previous two experiments. A three-alert haptic seat approach, the intermediate alternative tested, is recommended providing specific design requirements are met. / Ph. D.

Published Article / The link from medical scan images through data manipulation to additive manufacturing is well established. Various types of software are used to deliver the required .STL file(s). Often, the data manipulation will require the generation of new shapes around existing geometry, e.g. an implant that will replace missing bone tissue. This paper reports exploratory work undertaken to assess the feasibility of using haptic modelling and "virtual sculpting" software to generate novel designs of vertebrae implants for correction of spinal curvature. .STL data of several vertebrae, originating from CT scans, was imported into the Freeform system from SensAble technologies. It was used to create immutable "bucks" around which the user "sculpted" three-dimensional implant geometries. It must be noted that the designs have not been medically assessed and were for demonstration purposes only. However, the process route followed did prove to be feasible and offered some particular advantages, e.g. a precise fit between the implant and the vertebra and the possibility of enabling the direct intervention of medics in the implant design process.

A tier 1 automotive components supplier has developed a virtual user interface system for the purpose of replacing currently existing physical buttons mounted on automotive steering wheels. The system is capable of generating acoustic and vibratory feedback to the user for the purpose of mimicking the sound and feel of mechanical buttons. The work performed in this thesis served to investigate what the input waveform should be to the system in order to generate a desired audio output signal. Additionally, subjective testing in the form of a sound jury was conducted in order to identify which types of sounds should be associated with which command functions in order to indicate successful initiation of the intended function. A model for grouping command functions into banks, where each bank is assigned a single sound, was then developed for the purpose of reducing the total number of button sounds used in an automotive environment.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2009. / The input orientation of the excavators in use today usually comprises two joysticks that control the actuator links individually. In order to perform an excavation task, several different combinations of joystick inputs are required, placing high psychomotor demands on the operator. In training an operator this creates a steep learning curve, with a lengthy training time and a reasonable amount of experience being required to perform an excavation task skilfully. In this master’s thesis a haptic1 device was developed, resolving input ergonomics and creating a single input device capable of providing feedback to the operator. The design and construction of the haptic device, with the related control scheme, is presented and discussed. The control scheme combines position and rate control, and relates all the actuator joint positions to a single end-effector point. The control and ergonomic aspects of the haptic device were tested and compared to the traditional two joystick control setup by means of the implementation of a virtual excavator simulator. The simulation was developed in MATLAB, and virtual excavator displayed in an openGL window. The objective of this study was to evaluate the human factors related to the input orientation. Ten inexperienced test subjects were recruited to perform four sets of tests, where each test required a different level of operator skill. The results indicated that, on average, the test subjects had an increased level of performance after training on the haptic device. These results strongly support the hypothesis that haptic control simplifies the operational tasks required for operating an excavator. 1The word haptic means of, or relating to, the sense of touch, or tactile

This thesis presents a series of studies to explore and understand the design of eyes-free interfaces for mobile devices. The motivation is to devise a holistic design concept that is based on the WIMP paradigm and is adapted to the requirements of mobile user interaction. It is proposed that audio is a very efficient and effective modality for use in an eyes-free mobile interface. Methods to transfer the WIMP paradigm to eyes-free interfaces are proposed and evaluated. Guidelines for the implementation of the paradigm are given and – by means of an example – a holistic design concept is proposed. This thesis begins with an introduction to and critical reflection of re- currently important themes and research methods from the disciplines of psychoacoustics, psychology, and presence research. An overview of related work is given, paying particular attention to the use of interface metaphors in mobile eyes-free interfaces. The notion of distance is discussed as a method to prioritise, structure, and manage attention in eyes-free interfaces. Practical issues arising from sources becoming inaudible with increasing distance can be addressed by proposing a method modeled on echo location. This method was compared to verbally coded distance information and proved useful for identifying the closest of several objects, while verbally coded distance infor- mation was found to be more efficient for identifying the precise distance of an object. The knowledge gained from the study can contribute to improv- ing other applications, such as GPS based navigation. Furthermore, the issue of gaining an overview of accessible objects by means of sound was exam- ined. The results showed that a minimum of 200 ms between adjacent sound samples should be adhered to. Based on these findings, both earcons and synthesized speech are recommendable, although speech has the advantage of being more flexible and easier to learn. Monophonic reproduction yields comparable results to spatial reproduction. However, spatial reproduction has the additional benefit of indicating an item’s position. These results are transferable and generally relevant for the use of audio in HCI. Tactile interaction techniques were explored as a means to interact with an auditory interface and were found to be both effective and enjoyable. One of the more general observations was that 2D and 3D gestures were intuitively used by participants, who transferred their knowledge of established gestures to auditory interfaces. It was also found that participants often used 2D ges- tures to select an item and proceeded to manipulate it with a 3D gesture. The results suggest the use of a small gesture set with reversible gestures for do/undo-type actions, which was further explored in a follow up study. It could be shown that simple 3D gestures are a viable way of manipulating spatialized sound sources in a complex 3D auditory display. While the main contribution of this thesis lies in the area of HCI, pre- viously unresearched issues from adjacent disciplines that impact the user experience of auditory interfaces have been addressed. It was found that regular, predictable movement patterns in 3D audio spaces cause symptoms of simulator sickness. However, these were found to be minor and only oc- curred under extreme conditions. Additionally, the influence of the audio reproduction method on the perception of presence, social presence, and realism was examined. It was found that both stereophonic and binaural reproduction have advantages over monophonic sound reproduction: stereo- phonic sound increases the perception of social presence while binaural sound increases the feeling of being present in a virtual environment. The results are important contributions insofar as one of the main applications of mobile devices is voice based communication; it is reasonable to assume that there will be an increase in real-time voice based social and cooperative networking applications. This thesis concludes with a conceptual design of a system called “Foogue”, which uses the results of the previous experiments as the basis of an eyes-free interface that utilizes spatial audio and gesture input.

An increasing amount of information content used in schools, work and everyday living is being presented in graphical form, creating accessibility challenges for individuals who are blind or visually impaired, especially in dynamic environments, such as over the internet. Refreshable haptic displays that can interact with computers can be used to access such information tactually. Main focus of this study was the development of specialized computer applications allowing users to actively compensate for the inherent issues of haptics when exploring visual diagrams as compared to vision, which we hypothesized, would improve the usability of such devices. An intuitive zooming algorithm capable of automatically detecting significant different zoom levels, providing auditory feedback, preventing cropping of information and preventing zooming in on areas where no features were present was developed to compensate for the lower spatial resolution of haptics and was found to significantly improve the performance of the participants. Another application allowing the users to perform dynamic simplifications on the diagram to compensate for the serial based nature of processing 2D geometric information was tested and found to significantly improve the performance of the participants. For both applications participants liked the user interface and found it more usable, as expected. In addition, in this study we investigated methods that can be used to effectively present different visual features as well as overlaying features present in the visual diagrams. Three methods using several combinations of tactile and auditory modalities were tested. We found that the performance significantly improves when using the overlapping method using different modalities. For tactile only methods developed for deaf blind individuals, the toggle method was surprisingly preferred as compared to the overlapping method.