843 research outputs found
Keep Your Eyes above the Ball: Investigation of Virtual Reality (VR) Assistive Gaming for Age-Related Macular Degeneration (AMD) Visual Training
Humans are beyond all visual beings since most of the outside information is gathered through the visual system. When the aging process starts, visual functional damages become more and more common and the risk of developing visual impairment is higher. Age-related macular degeneration (AMD) is one of the main afflictions that leads to severe damage to the optical system due to the aging process. The ones affected lose the ability to use the central part of vision, essential for accurate visual information processing.
Even if less accurate, peripheral vision remains unaffected, hence medical experts have developed training procedures to train patients to use peripheral vision instead to navigate their environment and continue their daily lives. This type of training is called eccentric viewing. However, there are several shortcomings in current approaches, such as not being engaging or individualizable enough nor cost and time-effective.
The main scope of this dissertation was to find out if more engaging and individualizable methods can be used for peripheral training of AMD patients. The current work used virtual reality (VR) gaming to deliver AMD training; the first time such an approach was used for eccentric viewing training. In combination with eye-tracking, real-time individualized assistance was also achieved. Thanks to an integrated eye-tracker in the headset, concentric gaze-contingent stimuli were used to redirect the eyes toward an eccentric location. The concentric feature allowed participants to choose freely and individually their peripheral focus point.
One study investigated the feasibility a VR system for individualized visual training of ophthalmic patients, two studies investigated two types of peripheral stimuli (three spatial cues and two optical distortions) and the last study was a case study looking into the feasibility of such an approach for a patient with late AMD.
Changes in gaze directionality were observed in all the last three studies for one specific spatial cue, a concentric ring. In accordance with the literature, the gaze was directed spontaneously toward the most effective peripheral position. The last study additionally proved gaming feasible for future testing of the elderly AMD population. The current work opened the road to more individualized and engaging interventions for eccentric viewing training for late AMD
Efficient image-based rendering
Recent advancements in real-time ray tracing and deep learning have significantly enhanced the realism of computer-generated images. However, conventional 3D computer graphics (CG) can still be time-consuming and resource-intensive, particularly when creating photo-realistic simulations of complex or animated scenes. Image-based rendering (IBR) has emerged as an alternative approach that utilizes pre-captured images from the real world to generate realistic images in real-time, eliminating the need for extensive modeling. Although IBR has its advantages, it faces challenges in providing the same level of control over scene attributes as traditional CG pipelines and accurately reproducing complex scenes and objects with different materials, such as transparent objects. This thesis endeavors to address these issues by harnessing the power of deep learning and incorporating the fundamental principles of graphics and physical-based rendering. It offers an efficient solution that enables interactive manipulation of real-world dynamic scenes captured from sparse views, lighting positions, and times, as well as a physically-based approach that facilitates accurate reproduction of the view dependency effect resulting from the interaction between transparent objects and their surrounding environment. Additionally, this thesis develops a visibility metric that can identify artifacts in the reconstructed IBR images without observing the reference image, thereby contributing to the design of an effective IBR acquisition pipeline. Lastly, a perception-driven rendering technique is developed to provide high-fidelity visual content in virtual reality displays while retaining computational efficiency.Jüngste Fortschritte im Bereich Echtzeit-Raytracing und Deep Learning haben den Realismus computergenerierter Bilder erheblich verbessert. Konventionelle 3DComputergrafik (CG) kann jedoch nach wie vor zeit- und ressourcenintensiv sein, insbesondere bei der Erstellung fotorealistischer Simulationen von komplexen oder animierten Szenen. Das bildbasierte Rendering (IBR) hat sich als alternativer Ansatz herauskristallisiert, bei dem vorab aufgenommene Bilder aus der realen Welt verwendet werden, um realistische Bilder in Echtzeit zu erzeugen, so dass keine umfangreiche Modellierung erforderlich ist. Obwohl IBR seine Vorteile hat, ist es eine Herausforderung, das gleiche Maß an Kontrolle über Szenenattribute zu bieten wie traditionelle CG-Pipelines und komplexe Szenen und Objekte mit unterschiedlichen Materialien, wie z.B. transparente Objekte, akkurat wiederzugeben. In dieser Arbeit wird versucht, diese Probleme zu lösen, indem die Möglichkeiten des Deep Learning genutzt und die grundlegenden Prinzipien der Grafik und des physikalisch basierten Renderings einbezogen werden. Sie bietet eine effiziente Lösung, die eine interaktive Manipulation von dynamischen Szenen aus der realen Welt ermöglicht, die aus spärlichen Ansichten, Beleuchtungspositionen und Zeiten erfasst wurden, sowie einen physikalisch basierten Ansatz, der eine genaue Reproduktion des Effekts der Sichtabhängigkeit ermöglicht, der sich aus der Interaktion zwischen transparenten Objekten und ihrer Umgebung ergibt. Darüber hinaus wird in dieser Arbeit eine Sichtbarkeitsmetrik entwickelt, mit der Artefakte in den rekonstruierten IBR-Bildern identifiziert werden können, ohne das Referenzbild zu betrachten, und die somit zur Entwicklung einer effektiven IBR-Erfassungspipeline beiträgt. Schließlich wird ein wahrnehmungsgesteuertes Rendering-Verfahren entwickelt, um visuelle Inhalte in Virtual-Reality-Displays mit hoherWiedergabetreue zu liefern und gleichzeitig die Rechenleistung zu erhalten
Brain Computations and Connectivity [2nd edition]
This is an open access title available under the terms of a CC BY-NC-ND 4.0 International licence. It is free to read on the Oxford Academic platform and offered as a free PDF download from OUP and selected open access locations.
Brain Computations and Connectivity is about how the brain works. In order to understand this, it is essential to know what is computed by different brain systems; and how the computations are performed.
The aim of this book is to elucidate what is computed in different brain systems; and to describe current biologically plausible computational approaches and models of how each of these brain systems computes.
Understanding the brain in this way has enormous potential for understanding ourselves better in health and in disease. Potential applications of this understanding are to the treatment of the brain in disease; and to artificial intelligence which will benefit from knowledge of how the brain performs many of its extraordinarily impressive functions.
This book is pioneering in taking this approach to brain function: to consider what is computed by many of our brain systems; and how it is computed, and updates by much new evidence including the connectivity of the human brain the earlier book: Rolls (2021) Brain Computations: What and How, Oxford University Press.
Brain Computations and Connectivity will be of interest to all scientists interested in brain function and how the brain works, whether they are from neuroscience, or from medical sciences including neurology and psychiatry, or from the area of computational science including machine learning and artificial intelligence, or from areas such as theoretical physics
Measuring the Effects of Multi-Sensory Stimuli in the Mixed Reality Environment for Tourism Value Creation
This thesis explores the impact of technology-enhanced multisensory stimuli on visitors'
value judgments and behavioural intentions at tourist attractions. The study is based on
the Tourism Value Framework (Smith and Colgate, 2007), which examines the influence
of tourism environment and experience cues on tourist behaviour. To achieve the
objective, four key areas were critically reviewed: 1) value creation in attraction-based
tourism, 2) multisensory experience literature including experiencescape research, 3)
immersion, and 4) mixed-reality technology (Objective 1).
Primary data collection involved two research phases. The first phase included ten semistructured
focus group interviews with visitors at two multisensory mixed-reality tourism
locations in Finland (Objective 2). These interviews provided insights into visitors'
perspectives on value formation, immersive experiences, and mixed-reality technologies.
Thematic analysis of the data revealed five themes and seventeen subthemes, including
context-specific subthemes, which contributed to understanding the multisensory tourism
experience and technology-enhanced experience.
Based on ten hypotheses, a qualitative S-I-V-A value creation framework was developed
for technology-enhanced multisensory mixed reality tourism environments. The second
phase aimed to examine and validate the proposed model by collecting survey responses
from 317 visitors to a multisensory mixed reality tourist environment. Covariance-based
Structural Equation Modelling (CB-SEM) was used for data analysis (Objective 3). The
research's significant achievement is the creation of the S-I-V-A value creation framework
for technology-enhanced multisensory mixed reality tourist environments, derived from
the study's discoveries (Objective 4).
The thesis concludes by summarizing the theoretical contributions of this research and
offering recommendations to developers and designers in the tourism and mixed-reality
sectors. It acknowledges the study's limitations and suggests potential directions for
future research
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Neurobiological and behavioural studies of individual variation in cue-evoked motivation across rodents and humans
For a subset of individuals known as sign-trackers, discrete pavlovian cues associated with
rewarding stimuli can acquire incentive properties in their own right. When they do so, cues
have the ability to exert control over behaviour, which appears to contribute to specific sets
of symptoms within neuropsychiatric conditions such as substance use disorder or post-
traumatic stress disorder.
Characterising the neurobiological mechanisms mediating variation in cue responsivity is
essential to better understand differences in the susceptibility to such disorders. Converging
evidence points towards the involvement of dopaminergic neurotransmission in the nucleus
accumbens core in the development of sign-tracking; yet, whether this phenotype is
associated with specific accumbal postsynaptic properties is unknown. The first section of
this thesis investigated the morphology of dendritic spines, presynaptic and postsynaptic
markers of activity in the nucleus accumbens core of male and female rats following a
pavlovian conditioned approach procedure. Results suggest that individuals who attributed
the most incentive salience to a food cue displayed unique dendritic spine organisation; such
observations were modulated by the presence or absence of reward. The influence of the
oestrous cycle and the altering of sign-tracking by propranolol were also examined.
Developing transitional tools to detect sign-tracking in humans might provide a valuable
means to identify profiles conferring vulnerability to maladaptive behaviours. The second
section of this thesis describes responses of male and female participants in a computerised
image-based pavlovian procedure, a virtual room-based pavlovian environment, and a ‘real-
life’ pavlovian procedure in which participants physically interacted with the apparatus. The
second and third approaches enabled the development of distinct conditioned phenotypes.
Because rodent sign-trackers are more impulsive, the relationship between phenotypes and
impulsivity was also considered.
This thesis provides further insight into the neural underpinnings of motivated behaviours
and offers guidance for future translational investigation
Central and Eastern European Literary Theory and the West
The twentieth century saw intensive intellectual exchange between Eastern and Central Europe and the West. Yet political and linguistic obstacles meant that many important trends in East and Central European thought and knowledge hardly registered in Western Europe and the US. This book uncovers the hidden westward movements of Eastern European literary theory and its influence on Western scholarship
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