90 research outputs found

    Defining Areas of Interest Using Voronoi and Modified Voronoi Tesselations to Analyze Eye-Tracking Data

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    Eye tracking is a technology used to track where someone is looking. Eye-tracking technology is often used to study what people focus on when looking at a photo of another person. The eye-tracking technology records points on a photo that a person is looking at. When the photo being looked at shows a person, the points can be categorized by body part such as head, right hand, left hand, and torso. This thesis presents the use of partially circular areas to define the body parts of the person in the photo and therefore categorize the points collected by the eye-tracker. The participants for this study consisted of 20 people who practiced yoga and 20 people who did not practice yoga. These participants were asked to look at 22 pictures of a person standing in different postures. In this thesis, we analyze differences in how those who practice yoga look at the pictures compared to those who do not practice yoga using the partially circular areas to define where the points belong

    The effects of augmented virtuality on presence, workload, and input performance

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    Head-Mounted Displays (HMDs) offer, more than any easily accessible technology that has come before, the sensation of presence – that feeling that you are “really there” in a virtual world. However, HMDs cut the wearer off from the real world, making even trivial interactions, such as having a drink or typing, difficult and frustrating. In the home context where these devices are most likely to be used, such interactions are commonplace, and in order to execute them, users have to remove the HMD (“peep”), breaking their sense of presence. How, then, can real-world interactions during HMD usage be facilitated such that presence is damaged as little as possible? Previous work indicates that Augmented Virtuality (AV), a technique that allows the wearer of an HMD to see through it when they need to, is a promising answer to this question. However, direct comparisons between AV and VR that thoroughly account for presence and workload are lacking. To corroborate previous findings, and to address some of the gaps in the current literature, we conducted a quantitative user experiment to compare our own implementation of AV to VR in terms of presence, workload, and typing performance. The experiment followed a betweengroups design with participants selected via pseudo-random convenience sampling of university students. To simulate the context of home usage – an extended immersive session that must occasionally be interrupted – we designed a mixed reality game that periodically required the player to interact with real-world objects before they could proceed. Participants in the experimental group played the game using our AV system to assist them in completing the required real-world tasks. Participants in the control group used pure VR to play the game and had to peep. This allowed us to directly compare AV to VR in terms of the levels of presence and workload experienced. These data were gathered using post-hoc self-report questionnaires. To measure and compare typing performance under various conditions, we created desktop, VR, and AV versions of a typing test that participants had to complete. We found that typing performance in AV was significantly better than in VR, but did not reach the levels achieved in baseline desktop conditions. While there was not a significant difference in the overall level of workload associated with using AV compared to VR, participants in the AV condition were able to interact successfully with the real world without having to remove the HMD, and reported being significantly less frustrated than those in the VR condition. Finally, AV users reported significantly higher levels of presence than those who used VR

    Smart Technologies for Precision Assembly

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    This open access book constitutes the refereed post-conference proceedings of the 9th IFIP WG 5.5 International Precision Assembly Seminar, IPAS 2020, held virtually in December 2020. The 16 revised full papers and 10 revised short papers presented together with 1 keynote paper were carefully reviewed and selected from numerous submissions. The papers address topics such as assembly design and planning; assembly operations; assembly cells and systems; human centred assembly; and assistance methods in assembly

    Smooth Pursuit and Antisaccade Eye Movements as Endophenotypes in Schizophrenia Spectrum Research

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    Smooth pursuit eye movement (SPEM) and antisaccade deficits have been proposed as schizophrenia spectrum endophenotypes. An endophenotype is a behavioural or biological deficit thought to represent, more closely than the disease phenotype, the effects of an underlying disease gene. Oculomotor endophenotypes possess phenotypic homogeneity, well-understood neural correlates and objective assessment and may thus be used as phenotypes in linkage studies. This thesis investigated a number of issues concerning the reliability and validity of the SPEM and antisaccade tasks as schizophrenia spectrum endophenotypes (and two tasks thought to be unimpaired in the schizophrenia spectrum, visual fixation and prosaccades). The schizophrenia spectrum encompasses not only people with schizophrenia but any population with an increased frequency of schizophrenia-related phenotypes or genotypes, such as schizotypal individuals or first-degree relatives of schizophrenia patients. A valid endophenotype should thus be detected in these populations. Study I investigated reliability, namely internal consistency and temporal stability, of eye movements in healthy individuals. Study II utilised first-episode psychosis patients and healthy controls, aiming to detect behavioural oculomotor deficits in the absence of secondary confounds that may be encountered in chronic schizophrenia. Study III assessed performance in siblings discordant for schizophrenia. Study IV explored the relationship between psychometric schizotypy and oculomotor performance. Study V examined possible state effects of procyclidine, an anticholinergic compound often administered to schizophrenia patients, on performance in a patient group. The results generally confirmed the validity of the SPEM and antisaccade deficits as schizophrenia spectrum endophenotypes: Oculomotor performance was mostly stable both within and between assessments. SPEM and antisaccade impairments were observed in first­episode psychosis patients and schizophrenia patients and their healthy siblings. Antisaccade, but not SPEM, impairments were associated with high levels of schizotypy. State effects of procyclidine on SPEM and antisaccade performance were observed, suggesting the need to consider the influence of pharmacological treatment in future patient studies. These findings suggest that SPEM and antisaccade deficits may be studied profitably as endophenotypes in schizophrenia spectrum research

    Legibility of machine readable codes used for gas turbine part tracking

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    Gas turbines are comprised of many parts, which are often expensive and required to survive a harsh environment for significant periods (with or without reconditioning). To differentiate between parts, and facilitate keeping accurate historical records, they are often given a unique identification number. However, manually recording and tracking these is difficult. This has led to increased adoption of machine readable codes to help reduce or eliminate many of the issues currently faced (mostly human error). The harsh environment of a gas turbine means that typical methods of applying machine readable codes, such as printed adhesive labels, are simply not durable enough. Direct part marking (DPM) is necessary to ensure the desired longevity of the code over the part's useful life. The research presented in this thesis was approached in two main phases. Firstly, the author sought to investigate the technical solutions available for the elements required of a part tracking system (encoding, marking and scanning). This included identifying the characteristics of each and their compatibility with one other (across elements). In conjunction with Alstom, criteria were identified that were used as a basis for comparison so that the preferred technical solutions could be determined. The outcome of this process was enhanced by the author developing a number of industrial contacts experienced in implementing part tracking systems. The second phase related to the legibility of the codes. The harsh environment of a gas turbine results in surface degradation that may in turn reduce the legibility of any machine readable codes present. To better understand why read failures occur, the author _rst looked to the scanning process. Data Matrix symbols (marked via dot peen) require the scanner to capture an image for processing. Image capture is typically achieved using a charge-coupled device (CCD), each pixel of which induces a charge proportional to the incident illumination. This illumination is received via reflection from the surface of the part and hence the Data Matrix marked on it. Several surface features were identified that govern the way in which the part surface will reflect light back to the scanner: surface roughness, dot geometry and surface colour. These parameters are important because they link the degradation mechanisms occurring { broadly categorised as deposition, erosion or corrosion { with the scanning process. Whilst the degradation mechanisms are distinctly different in their behaviour, their effect on surface reflectivity is common in that they can all be characterised via the surface parameters identified. This was deduced theoretically and so the author completed tests (utilising shot blasting to change the surface roughness and oxidation to change its colour, independently) to show that these surface parameters do indeed change with the introduction of surface degradation and that there is a commensurate change in symbol legibility. Based on the learning derived with respect to Data Matrix legibility, the author has proposed a framework for developing a tool referred to as a Risk Matrix System. This tool is intended to enhance the application of part tracking to gas turbine engines by enabling symbol durability to be assessed based on the expected operating conditions. The research presented is the first step in fully understanding the issues that affect the legibility of symbols applied to gas turbine parts. The author's main contribution to learning has been the identification of knowledge from various other sources applicable to this situation and to present it in a coherent and complete manner. From this foundation, others will be able to pursue relevant issues further; the author has made a number of recommendations to this effect

    Proceedings of the Seventeenth Annual Conference on Manual Control

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    Manual control is considered, with concentration on perceptive/cognitive man-machine interaction and interface

    Interaction and the Art of User-Centered Digital Musical Instrument Design

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    This thesis documents the formulation of a research-based practice in multimedia art, technology and digital musical instrument design. The primary goal of my research was to investigate the principles and methodologies involved in the structural design of new interactive digital musical instruments aimed at performance by members of the general public, and to identify ways that the design process could be optimized to increase user adoption of these new instruments. The research was performed over three years and moved between studies at the University of Maine, internships in New York, and specialized research at the Input Devices and Music Interaction Laboratory at McGill University. My work is presented in two sections. The first covers early studies in user interaction and exploratory works in web and visual design, sound art, installation, and music performance. While not specifically tied to the research topic of user adoption of digital musical instruments, this work serves as the conceptual and technical background for the dedicated work to follow. The second section is dedicated to focused research on digital musical instrument design through two major projects carried out as a Graduate Research Trainee at McGill University. The first was the design and prototype of the Noisebox, a new digital musical instrument. The purpose of this project was to learn the various stages of instrument design through practical application. A working prototype has been presented and tested, and a second version is currently being built. The second project was a user study that surveyed musicians about digital musical instrument use. It asked questions about background, instrument choice, music styles played, and experiences with and attitudes towards new digital musical instruments. Based on the results of the two research projects, a model of digital musical instrument design is proposed that adopts a user-centered focus, soliciting user input and feedback throughout the design process from conception to final testing. This approach aims to narrow the gap between conceptual design of new instruments and technologies and the actual musicians who would use them

    Software Acquisition Improvement in the Aeronautical Systems Center

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    In the past 20 years, over 150 recommendations have been made to improve software systems development by organizations such as the Defense Science Board, National Research Council and the U.S. General Accountability Office. It has been discovered that many of these recommendation have remained unimplemented. This research had the purpose of confirming the application of these previous recommendations to improve software acquisition in the Aeronautical Systems Center. This was accomplished through interviews with 20 software practitioners in the acquisition community and the review of relevant literature. Through the analysis of the interviews and literature, this research was able to confirm that many of the recommendations have been applied in programs throughout ASC
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