Personalized Digital Body: Enhancing Body Ownership and Spatial Presence in Virtual Reality

person\u27s sense of acceptance of a virtual body as his or her own is generally called virtual body ownership (VBOI). Having such a mental model of one\u27s own body transferred to a virtual human surrogate is known to play a critical role in one\u27s sense of presence in a virtual environment. Our focus in this dissertation is on top-down processing based on visual perception in both the visuomotor and the visuotactile domains, using visually personalized body cues. The visual cues we study here range from ones that we refer to as direct and others that we classify as indirect. Direct cues are associated with body parts that play a central role in the task we are performing. Such parts typically dominate a person\u27s foveal view and will include one or both of their hands. Indirect body cues come from body parts that are normally seen in our peripheral view, e.g., legs and torso, and that are often observed through some mediation and are not directly associated with the current task. This dissertation studies how and to what degree direct and indirect cues affect a person\u27s sense of VBOI for which they are receiving direct and, sometimes, inaccurate cues, and to investigate the relationship between enhanced virtual body ownership and task performance. Our experiments support the importance of a personalized representation, even for indirect cues. Additionally, we studied gradual versus instantaneous transition between one\u27s own body and a virtual surrogate body, and between one\u27s real-world environment and a virtual environment. We demonstrate that gradual transition has a significant influence on virtual body ownership and presence. In a follow-on study, we increase fidelity by using a personalized hand. Here, we demonstrate that a personalized hand significantly improves dominant visual illusions, resulting in more accurate perception of virtual object sizes

Carrier Transport of Graphene Quantum Device and its Application for Ferroelectric Memory

Department of PhysicsCarrier transport in lateral tunnel junction was studied to apply it for ferroelectric memory devices in theoretical calculations and experimental methods. The edge metal-insulator-metal (EMIM) lateral tunnel junction on ferroelectric layer structure was proven to be a large resistive switching memory device theoretical calculation. The lateral tunnel junction in 2-dimensional material was fabricated with graphene and selectively functionalized graphene. The quantum mechanical tunneling of both 3D and 2D lateral tunnel junction was investigated to apply ferroelectric memory device. Not only the resistive switching memory device, the ferroelectric memory device by using graphene field effect transistor with novel read-out mechanism was studied. Recently, new memory devices substituting currently used DRAM and flash memory are more actively studied because the memory cell size reaches the physical limits less than 10 nanometer scale. Extreme ultraviolet (EUV) photolithography has been adapted to one of the way for overcoming the scaling issue of memory device. Otherwise, the 3D XPoint nonvolatile memory device has been made by Intel Corp. with higher speed than current NAND flash memory. Based on the electrostatic potential change by ferroelectric layer, we studied the new memory device without selection devices by read-out using two crossing lines. Theoretical calculation of tunnel current density at EMIM structure on ferroelectric layer shows the ~1013 switching ratio between polarization up and down state. The read-out mechanism is applying the half of turn on voltage on word and bit line which is connected to the drain and source electrode in lateral tunnel junction. The writing memory cell can be performed with applying voltages on word, bit, and writing line connected to the bottom of ferroelectric layer. This structure is the basic idea for nonvolatile memory device without selection devices. Based on this research, the lateral tunnel junction in two dimensional materials was studied for memory application. We fabricated graphene/fluorinated-graphene/graphene tunnel junction by using selective insulation of graphene layer after E-beam lithography process. Small gap formed in lateral direction between two graphene electrodes works as a tunnel barrier. The theoretical calculation of thermionic emission current and tunneling current were compared with the current-voltage measurement of fabricated tunnel junction. We confirmed that the graphene lateral tunnel junction can be a good candidate for ferroelectric memory devices. Moreover, we studied that read-out of transconductance of graphene field effect transistor on ferroelectric material can be a new way for defining the memory cell state. Using this method, the series resistance of word and bit line cells connected to read-out cell has no effect during read-out. In case of graphene, the transconductance can be switched from negative to positive depending on the polarization direction of ferroelectric layer due to the energy band structure of graphene. We can also apply this read-out mechanism to 3D tunnel junction even though it has no dramatic effect than the graphene field effect transistor. However, considering the commercialization of this kind of memory device, the 3D tunnel junction can be more adaptable than the graphene transistor.clos

Unveiling the Direct Correlation between the CVD-Grown Graphene and the Growth Template

Chemical vapor deposition (CVD) is known to produce continuous, large-area graphene sheet with decent physical properties. In the CVD process, catalytic metal substrates are typically used as the growth template, and copper has been adopted as the representative material platform due to its low carbon solubility and resulting monolayer graphene growth capability. For the widespread industrial applications of graphene, achieving the high-quality is essential. Several factors affect the qualities of CVD-grown graphene, such as pressure, temperature, carbon precursors, or growth template. In this work, we provide detailed analysis on the direct relation between the metallic growth substrate (copper) and overall properties of the resulting CVD-grown graphene. The surface morphology of copper substrate was modulated via simple chemical treatments, and its effect on physical, optical, and electrical properties of graphene was analyzed. Based on these results, we propose a simple synthesis route to produce high-quality, continuous, monolayer graphene sheet, which can facilitate the commercialization of CVD graphene into realit

Schottky Barrier Modulation of Metal/4H-SiC Junction with Thin Interface Spacer Driven by Surface Polarization Charge on 4H-SiC Substrate

The Au/Ni/Al2O3/4H-SiC junction with the Al2O3 film as a thin spacer layer was found to show the electrical characteristics of a typical rectifying Schottky contact, which is considered to be due to the leakiness of the spacer layer. The Schottky barrier of the junction was measured to be higher than an Au/Ni/4H-SiC junction with no spacer layer. It is believed that the negative surface bound charge originating from the spontaneous polarization of 4H-SiC causes the Schottky barrier increase. The use of a thin spacer layer can be an efficient experimental method to modulate Schottky barriers of metal/4H-SiC junctions.open

Enhancing attention in autism spectrum disorder: comparative analysis of virtual reality-based training programs using physiological data

BackgroundThe ability to maintain attention is crucial for achieving success in various aspects of life, including academic pursuits, career advancement, and social interactions. Attention deficit disorder (ADD) is a common symptom associated with autism spectrum disorder (ASD), which can pose challenges for individuals affected by it, impacting their social interactions and learning abilities. To address this issue, virtual reality (VR) has emerged as a promising tool for attention training with the ability to create personalized virtual worlds, providing a conducive platform for attention-focused interventions. Furthermore, leveraging physiological data can be instrumental in the development and enhancement of attention-training techniques for individuals.MethodsIn our preliminary study, a functional prototype for attention therapy systems was developed. In the current phase, the objective is to create a framework called VR-PDA (Virtual Reality Physiological Data Analysis) that utilizes physiological data for tracking and improving attention in individuals. Four distinct training strategies such as noise, score, object opacity, and red vignette are implemented in this framework. The primary goal is to leverage virtual reality technology and physiological data analysis to enhance attentional capabilities.ResultsOur data analysis results revealed that reinforcement training strategies are crucial for improving attention in individuals with ASD, while they are not significant for non-autistic individuals. Among all the different strategies employed, the noise strategy demonstrates superior efficacy in training attention among individuals with ASD. On the other hand, for Non-ASD individuals, no specific training proves to be effective in enhancing attention. The total gazing time feature exhibited benefits for participants with and without ASD.DiscussionThe results consistently demonstrated favorable outcomes for both groups, indicating an enhanced level of attentiveness. These findings provide valuable insights into the effectiveness of different strategies for attention training and emphasize the potential of virtual reality (VR) and physiological data in attention training programs for individuals with ASD. The results of this study open up new avenues for further research and inspire future developments

Capacitive Heart-Rate Sensing on Touch Screen Panel with Laterally Interspaced Electrodes

It is demonstrated that the heart-rate can be sensed capacitively on a touch screen panel (TSP) together with touch signals. The existing heart-rate sensing systems measure blood pulses by tracing the amount of light reflected from blood vessels during a number of cardiac cycles. This type of sensing system requires a considerable amount of power and space to be implemented in multi-functional mobile devices such as smart phones. It is found that the variation of the effective dielectric constant of finger stemming from the difference of systolic and diastolic blood flows can be measured with laterally interspaced top electrodes of TSP. The spacing between a pair of non-adjacent top electrodes turns out to be wide enough to distinguish heart-rate signals from noises. With the aid of fast Fourier transform, the heart-rate can be extracted reliably, which matches with the one obtained by actually counting heart beats on the wrist

Ultrastructure of a Mobile Threadlike Tissue Floating in a Lymph Vessel

Observations of the primo vascular system (PVS) floating in lymph ducts were reported by various groups. There have been, however, no studies on the ultrastructure of the entire cross section of a primo vessel (PV) inside a lymph vessel with a transmission electron microscope (TEM). In the current study we took the TEM images of a cross section of the PV inside a lymph vessel. We used the Alcian blue staining method for the finding of the target PV in a lymphatic vessel by injecting the dye into the inguinal lymph nodes. The stained PV was harvested together with the lymph vessel and some parts of the specimens were used for studying with optical microscopes. Some other parts were treated according to a standard protocol for TEM. As the results the TEM study revealed the loosely distributed collagen fibers with plenty of empty spaces and the lumens with the endothelial nuclei. It turned out to be very similar to the ultrastructure of the PVs observed on the surfaces of internal organs. It also showed how compactly the PV is surrounded with lymphocytes. In conclusion, the detailed morphological features like the distribution of fibers in the PV were revealed and shown to be similar to another kind of the PV on the surfaces of internal organs