Thesis (M.S.)--Florida State University, 2006. / Advisor: Carl A. Moore, Florida State University, College of Engineering, Dept. of Mechanical Engineering. Title and description from dissertation home page (viewed June 8, 2006). Document formatted into pages; contains x, 107 pages. Includes bibliographical references.

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Multi-function interfaces have become increasingly pervasive and are frequently used in contexts which pose multiple demands on a single sensory modality. Assuming some degree of modularity in attentional processing and that using a different sensory channel for communication can reduce interference with critical visual tasks, one possibility is to divert some information through the touch sense. The goal of this Thesis is to advance our knowledge of relevant human capabilities and embed this knowledge into haptic communication design tools and procedures, in the interest of creating haptically supported interfaces that decrease rather than add to their users’ sensory and cognitive load. In short, we wanted to create tools and methods that would allow the creation of haptic signals (accomplished via display of either forces or vibrations) extending beyond the one bit of communication offered by current pagers and cellular phone buzzers. In our quest to create information-rich haptic signals we need to learn how to create signals that are differentiable. We also need to study ways to assign meanings to these signals and make sure that they can be perceived clearly when presented one after another even in environments where their recipient might be involved with other tasks. These needs frame the specific research goals of this thesis. Most of the results described here were obtained through the study of tactile (in the skin) rather than proprioceptive (force feedback) stimuli. We begin by presenting several methods to create, validate and contrast tactile stimulus dissimilarity data and investigate the design of a waveform intended to be a tactile perceptual intermediate between a square waveform and a triangle waveform. Next, we explore methods to create and test tactile signal-meaning associations and document a surprising ability of participants to exhibit high recall of quickly learned associations at two weeks in a first examination of longitudinal recall of tactile stimuli. We then present methods to measure tactile stimulus masking and identify crucial perceptual thresholds relating to stimulus temporal spacing in an exploration into the masking effects of common-onset vibrotactile stimuli. Finally, we present methods to test haptic and multimodal perception in simulated scenarios including a method to simulate and control cognitive workload; and provide evidence that the commonly-used device of multimodal signal reinforcement can adversely impact performance in an ongoing primary task. The research presented in this Thesis has implications for the design of signals to be used in displays that are emerging in embedded computing environments such as cars, games, cellular phones, and medical devices. / Science, Faculty of / Computer Science, Department of / Graduate

Perception relies on the integration of numerous noisy inputs (cues). Cue combination has been relatively understudied in somatosensation, compared to vision and audition. Here, we investigated whether haptic cutaneous and hand configuration cues are combined optimally to discriminate between coin-sized discs of different sizes. When the hand is open such that the thumb and index fingers span the diameter of a disc to contact its perimeter, cutaneous cues occur from the indentation of the skin caused by the curvature of the disc (smaller discs cause greater indentation). Simultaneously, the hand configuration cue (relating to the perceived distance between fingers), provides an additional cue to size. These cues may vary in their reliability. In three experiments involving 34 participants, we measured these cues and considered three hypotheses for how humans may use them: humans rely solely on the least noisy cue (Winner-Take-All Model), humans combine cues based on a simple average (Average-Measurement Model), or humans combine cues via an optimal weighted average (Optimally-Weighted Model). Each experiment tested participants using a two-interval forced-choice (2IFC) paradigm with 3D printed disc stimuli. On each trial, under occluded vision, participants felt two discs sequentially and responded which felt larger. Participants were tested with each finger’s cutaneous cue alone, the hand configuration cue alone, and all cues together. In two experiments, the presented discs were both circular. In a third experiment, unknown to participants, some of the presented discs were oval-like cue conflict stimuli. Participant performance was compared to predictions of the cue combination models. We conclude that humans may combine haptic cutaneous and hand configuration cues optimally to judge the size of held objects. / Thesis / Doctor of Philosophy (PhD) / The sense of touch is understudied compared to the senses of sight and hearing. But simply reaching for a coin without looking involves complex calculations and decision-making. We studied how the brain may approach tasks like this. We were interested in how well the brain deals with multiple sources of information that do not always agree with each other. We investigated these questions in computer simulations and in experiments with undergraduate participants. Using carefully designed 3D-printed discs, we tested dozens of participants across 3 different experiments. Our results show that humans may use information in the best possible way and applications relevant to VR and robot-assisted surgery.

Existing pedestrian navigation systems are mainly visual-based, sometimes with an addition of audio guidance. However, previous research has reported that visual-based navigation systems require a high level of cognitive efforts, contributing to errors and delays. Furthermore, in many situations a person’s visual and auditory channels may be compromised due to environmental factors or may be occupied by other important tasks. Some research has suggested that the tactile sense can effectively be used for interfaces to support navigation tasks. However, many fundamental design and usability issues with pedestrian tactile navigation displays are yet to be investigated. This dissertation investigates human-computer interaction aspects associated with the design of tactile pedestrian navigation systems. More specifically, it addresses the following questions: What may be appropriate forms of wearable devices? What types of spatial information should such systems provide to pedestrians? How do people use spatial information for different navigation purposes? How can we effectively represent such information via tactile stimuli? And how do tactile navigation systems perform? A series of empirical studies was carried out to (1) investigate the effects of tactile signal properties and manipulation on the human perception of spatial data, (2) find out the effective form of wearable displays for navigation tasks, and (3) explore a number of potential tactile representation techniques for spatial data, specifically representing directions and landmarks. Questionnaires and interviews were used to gather information on the use of landmarks amongst people navigating urban environments for different purposes. Analysis of the results of these studies provided implications for the design of tactile pedestrian navigation systems, which we incorporated in a prototype. Finally, field trials were carried out to evaluate the design and address usability issues and performance-related benefits and challenges. The thesis develops an understanding of how to represent spatial information via the tactile channel and provides suggestions for the design and implementation of tactile pedestrian navigation systems. In addition, the thesis classifies the use of various types of landmarks for different navigation purposes. These contributions are developed throughout the thesis building upon an integrated series of empirical studies.

Le système vibrissal des rongeurs est un modèle très utilisé pour l'étude des processus comportementaux et neurobiologiques qui sous-tendent la perception tactile, en particulier pendant l'exploration de la forme d'un objet, sa localisation, ou la rugosité de sa surface. Le but de cette thèse a été d'explorer les stratégies sensori-motrices impliquées dans une tâche de discrimination tactile, ainsi que l'activité neuronale qui sous-tend ce processus.De façon similaire aux doigts humains scannant un objet, les rongeurs peuvent balayer activement des surfaces avec les vibrisses de leur museau (mouvement appelé «whisking»). En laboratoire, les rats discriminent des niveaux de rugosité en faisant du whisking. D'après leurs conditions de vie naturelles, nous avons fait l'hypothèse que ces animaux peuvent discriminer des motifs spatiaux sans whisking. Pour le démontrer, nous avons développé une nouvelle tâche de discrimination dans laquelle les rats contactent des stimuli en courant à haute vitesse dans un couloir, de sorte à ce qu'il n'y a pas assez de temps pour un cycle de whisking. Les rats ont appris à discriminer des barres verticales régulièrement espacées d'une surface sans barres. Les vibrisses et le cortex somatosensoriel primaire sont impliqués dans la discrimination. Les animaux ont été également capables de discriminer les barres régulières de barres irrégulières. Nous avons montré que les rats ne font pas de whisking sur les stimuli, et qu'ils orientent leurs vibrisses du côté du stimulus récompensé environ 60ms après premier contact (Kerekes et al., 2017). Ces résultats montrent que les rats peuvent discriminer des stimuli sans faire de whisking.Dans une deuxième partie, nous avons analysé les mouvements vibrissaux et réponses neuronales thalamo-corticales évoquées chez le rat anesthésié par le passage des stimuli utilisés pendant la tâche. Les résultats préliminaires révèlent des mouvements vibrissaux à haute accélération, encodés différemment par le cortex selon le type de stimulus (barres régulières ou irrégulières). Quatre rats ont été enregistrés pour cette étude: deux d'entre eux ont été entraînés à la tâche de discrimination, et les deux autres ont été entraînés à une tâche non-tactile sur le même labyrinthe. Grâce à ces expériences, nous allons rechercher les effets potentiels de l'apprentissage sur le traitement neuronal des informations tactiles. Le développement combiné de la tâche comportementale et des enregistrements neuronaux sur rat anesthésié et éveillé vont nous permettre d'explorer de nouvelles questions sur la discrimination tactile, tel que le codage de la régularité de motifs spatiaux, et la modulation de ce codage par l'apprentissage. / The rodent whisker system is a widely used model to study behavioral and neurobiological processes underlying tactile perception, in particular during the exploration of an object shape, localization or surface roughness. The general goal of this Ph.D. work was to explore the sensori-motor strategies involved in a tactile discrimination task, as well as the neuronal activity underlying such ability. Similarly to human fingertips scanning an object, rodents are able to sweep their whiskers against surfaces in a rhythmic fashion (a process called whisking) to analyze spatial details. In most laboratory tasks, rats discriminate spatial patterns by whisking on them successively. Based on the life of these animals in the wild, we hypothesized that rodents could discriminate spatial patterns without whisking. To demonstrate this, we developed a novel task inciting the rats to touch the stimuli by running past them at such high speed that the time needed to complete a whisking cycle is not available. Rats learned to discriminate a surface with a series of vertical bars regularly spaced from a smooth surface. Both whiskers and neural activity in the primary somatosensory cortex were involved during the discrimination process. Rats could also discriminate an irregular series from the regular one. We showed that rats do not whisk on the stimuli, and that they orient their whisker arrays towards the rewarded stimulus as soon as 60ms after the first possible contact (Kerekes et al., 2017). These results demonstrate that rats can discriminate stimuli without actively whisking. A second project of this Ph.D. work focused on the analysis of whisker deflections and thalamo-cortical neuronal responses evoked in the anesthetized rat by the stimuli passing on the whiskers mimicking the tactile condition during the task. Preliminary results show the presence of high-acceleration events occurring during whisker stimulation. These events evoked significant cortical responses, that differed according to the stimulus type (irregular or regular series). Four rats have been recorded for this study, two of them were trained on the discrimination task, and the two others were trained on a non-tactile task on the same maze. With this data, we plan to search for potential effects of learning on neuronal treatment of tactile inputs. Both the development of the novel discrimination task and of neuronal recordings in anesthetized and awake rats will allow to tackle new questions on tactile discrimination processes, such as how spatial regularity or irregularity are encoded and how this encoding can be modulated by learning.

Using a wearable tactile display three experiments were conducted in which tactile messages were created emulating five standard US Army and Marine arm and hand signals for the military commands, namely: "Attention", "Halt", "Rally", "Move Out", and "Nuclear Biological or Chemical event (NBC)". Response times and accuracy rates were collected for novices responding to visual and tactile representations of these messages, which were displayed either alone or together in congruent or incongruent combinations. Results indicated synergistic effects for concurrent, congruent message presentations showing superior response times when compared to individual presentations in either modality alone. This effect was mediated by participant strategy. Accuracy similarly improved when both the tactile and visual presentation were concurrently displayed as opposed to separately. In a low workload condition, participants could largely attend to a particular modality, with little interference from competing signals. If participants were not given instructions as to which modality to attend to, participants chose that modality which was received first. Lastly, initial learning and subsequent training of intuitive tactile signals occurred rapidly with large gains in performance in short training periods. These results confirm the promise for tactile messages to augment visual messaging in challenging and stressful environments particularly when visual messaging is maybe preferred but is not always feasible or possible.

Our Third Ear aims to create a multi-sensory experience by fusing sight, touch, and sound. By creating a means of physically feeling music, listeners can connect with songs, bands, and individual musicians on a profoundly personal level. The potential for unintended applications like learning to play an instrument, broadening the understanding of music for people with hearing impairments, or providing a means of therapy are also exciting prospects. The purpose of this paper is to illustrate the process involved in creating a multi-sensory experience of music from concept to prototype. The culmination of interdisciplinary research and a broad range of creative technologies resulting in a working system. The multi-sensory experience consists of primarily tactile, but also visual responses triggered by music and executed in conjunction with aural music. Tactile investigation involved varied tactile sensations such as vibration, temperature, pressure, proprioception, and touch. Further research questioned the practicality, feasibility, and psychological impacts of using such sensations as well as where on the body such sensations would optimally be received. Visual research involved the visual representation of notes, chords, and sounds, as well as, how music could directly affect visuals in a real time environment. Additional research explored active interaction and passive interaction of visual cues using human computer interfaces. / Master of Fine Arts

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Thesis (M.S.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / 2031-01-01