3,544 research outputs found

    X3D Earth Terrain-Tile Production Chain for Georeferenced Simulation

    Get PDF
    Web3D '09: Proceedings of the 14th International Conference on 3D Web Technology, June 2009, Pages 159–166.The article of record as published may be found at https://doi.org/10.1145/1559764.1559789Broad needs for digital models of real environments such as 3D terrain or cyber cities are increasing. Many applications related to modeling and simulation require virtual environments constructed from real-world geospatial information in order to guarantee relevance and accuracy in the simulation. The most fundamental data for building virtual environments, terrain elevation and orthogonal imagery, is typically acquired using optical sensors mounted on satellites or airplanes. Providing interoperable and reusable digital models in 3D is important for promoting practical applications of high-resolution airborne imagery. This paper presents research results regarding virtual-environment representations of geospatial information, especially for 3D shape and appearance of virtual terrain. It describes a framework for constructing real-time 3D models of large terrain based on highresolution satellite imagery. This approach is also suitable for underwater bathymetry. The Extensible 3D Graphics (X3D) Geospatial Component standard is applied to produce X3D Earth models with global scope. Efficient rendering, network retrieval and data caching/removal must all be optimized simultaneously, across servers, networks and clients, in order to accomplish these goals properly. Details of this standard-based approach for providing an infrastructure for real-time 3D simulation merging high-resolution geometry and imagery are also presented. This work facilitates open interchange and interoperability across diverse simulation systems and is independently usable by governments, industry, scientists and the general public

    Teacher Emotion and Learning as Praxis: Professional Development that Matters

    Get PDF
    This ethnographic study analyses the diverse emotions emerging within one teacher professional development workshop that engaged teachers as creative writers. Participating teachers revealed a vibrant range of positive and negative emotions as they worked within institutional discourses that conflicted with their intrinsic beliefs about effective teaching. They revealed their emotional investment in their roles and their desires for meaningful practice in spite of pressures to abide by managerial practices. Researchers documented high levels of vulnerability, engagement and hope as participants engaged in writing as ‘praxis’ to experience their beliefs about effective pedagogy firsthand. These findings suggest that since teaching and learning is inherently an emotional experience, professional development needs to acknowledge a teacher’s complex emotional identity and to cultivate positive emotional growth. This study is relevant to teacher educators, preservice and practising teachers as it explores meaningful learning opportunities as a basis for effective teaching practice

    Brain amyloid in preclinical Alzheimer\u27s disease is associated with increased driving risk

    Get PDF
    INTRODUCTION: Postmortem studies suggest that fibrillar brain amyloid places people at higher risk for hazardous driving in the preclinical stage of Alzheimer's disease (AD). METHODS: We administered driving questionnaires to 104 older drivers (19 AD, 24 mild cognitive impairment, and 61 cognitive normal) who had a recent (18)F-florbetapir positron emission tomography scan. We examined associations of amyloid standardized uptake value ratios with driving behaviors: traffic violations or accidents in the past 3 years. RESULTS: The frequency of violations or accidents was curvilinear with respect to standardized uptake value ratios, peaking around a value of 1.1 (model r(2) = 0.10, P = .002); moreover, this relationship was evident for the cognitively normal participants. DISCUSSION: We found that driving risk is strongly related to accumulating amyloid on positron emission tomography, and that this trend is evident in the preclinical stage of AD. Brain amyloid burden may in part explain the increased crash risk reported in older adults

    Modeling Pedestrian and Bicyclist Crash Exposure with Location-Based Service Data

    Get PDF
    The rising popularity of non-motorized transportation has brought about safety risks. The inclusion of accurate traffic volume information is one of the key elements to produce robust outcomes when researching safety. The project investigates and enhances transportation safety for pedestrians and bicyclists, emphasizing the integration of Location-Based Services (LBS) data, particularly StreetLight data, to analyze traffic volume and associated risks. The calibration process demonstrates the significance of traffic volume as a key variable influencing prediction accuracy across pedestrian, bicyclist, and vehicle models. The crash analysis reveals a strong correlation between crash counts and traffic activity, with noteworthy findings emerging at the facility scale. The safety ranking analysis identifies higher and lower risk areas in the city. The spatial and temporal analysis at the street segment level highlights changes in traffic volumes before and during the COVID-19 period, along with distinct geographic patterns of activities at downtown and recreational locations. The project contributes to the knowledge and methodology surrounding transportation safety for non-motorized road users. By leveraging LBS data, the research provides comprehensive analyses of traffic patterns and safety considerations, aiming to create a safer environment for pedestrians and bicyclists

    Picture Quality and Sound Quality of OLED TVs

    Get PDF
    Unlike the past when cathode-ray tube (CRT) dominated display industry, many different types of flat panel displays (FPDs) are now leading the industry. Of these, organic light-emitting diode (OLED) display has recently become a next-generation display since this display is recognised as having advantages over other competing technologies in picture quality and form factor. With major attributes of picture quality considered, a series of evaluations based on objective measures was performed with an OLED TV compared to an LCD TV. OLED TV outperformed LCD TV 100 times in black, 20 times in colour contrast, 30% in dynamic range coverage, 50 times in local contrast and 20 times in viewing angle. In addition, sound quality of the OLED TV was assessed using both objective and subjective evaluation methods compared to conventional TV speakers since OLED panel speaker technology was recently commercialised. The OLED panel speaker showed better performance both in objective and subjective methods

    Disruption of cholinergic neurotransmission, within a cognitive challenge paradigm, is indicative of Aβ-related cognitive impairment in preclinical Alzheimer’s disease after a 27-month delay interval

    Get PDF
    Background Abnormal beta-amyloid (Aβ) is associated with deleterious changes in central cholinergic tone in the very early stages of Alzheimer’s disease (AD), which may be unmasked by a cholinergic antagonist (J Prev Alzheimers Dis 1:1–4, 2017). Previously, we established the scopolamine challenge test (SCT) as a “cognitive stress test” screening measure to identify individuals at risk for AD (Alzheimer’s & Dementia 10(2):262–7, 2014) (Neurobiol. Aging 36(10):2709-15, 2015). Here we aim to demonstrate the potential of the SCT as an indicator of cognitive change and neocortical amyloid aggregation after a 27-month follow-up interval. Methods Older adults (N = 63, aged 55–75 years) with self-reported memory difficulties and first-degree family history of AD completed the SCT and PET amyloid imaging at baseline and were then seen for cognitive testing at 9, 18, and 27 months post-baseline. Repeat PET amyloid imaging was completed at the time of the 27-month exam. Results Significant differences in both cognitive performance and in Aβ neocortical burden were observed between participants who either failed vs. passed the SCT at baseline, after a 27-month follow-up period. Conclusions Cognitive response to the SCT (Alzheimer’s & Dementia 10(2):262–7, 2014) at baseline is related to cognitive change and PET amyloid imaging results, over the course of 27 months, in preclinical AD. The SCT may be a clinically useful screening tool to identify individuals who are more likely to both have positive evidence of amyloidosis on PET imaging and to show measurable cognitive decline over several years

    Atypical Supernumerary Phantom Limb and Phantom Limb Pain in Two Patients with Pontine Hemorrhage

    Get PDF
    Phantom limbs are usually observed after amputation of extremities. In patients after a stroke, a similar but rarely occurring phenomenon consisting of the patient experiencing the presence of an additional limb has been described. This phenomenon, generally called supernumerary phantom limb (SPL), may be caused by lesions in the right or left cerebral hemisphere, but has been predominantly reported in patients who have had a right hemispheric stroke. We report two cases of atypical SPL and phantom limb pain (PLP) after pontine hemorrhage. The patients were treated conservatively and their symptoms lasted more than 1 month. This is the first report of SPLs after left pontine hemorrhage, and phantom perception and pain lasted longer than those in previously observed cases. Our results indicate that SPL may be more common than reported; therefore, thorough examinations are essential for the care of stroke patients

    Short Term Effects of Repetitive Transcranial Magnetic Stimulation in Patients with Catastrophic Intractable Tinnitus: Preliminary Report

    Get PDF
    ObjectivesThe short-term effects of low-frequency repetitive transcranial magnetic stimulation (rTMS) in the patients with catastrophic and intractable tinnitus were investigated.MethodsFifteen participants were recruited among patients with catastrophic intractable tinnitus to receive 1 Hz rTMS treatment. Tinnitus severity was assessed before rTMS and directly after sham or real rTMS using the tinnitus handicap inventory (THI) and visual analog scale (VAS).ResultsThere was no statistical difference in the THI score before and after sham stimulation. However, after 5 replications of real rTMS there was statistically significant reduction in THI score. Eight patients showed a decrease of more than 10 in THI score. Patients who showed a vast change in THI score after rTMS also showed a large decrease in their VAS score (r=0.879, P<0.001). Duration of tinnitus and change of THI score showed statistically significant moderate negative correlation (r=-0.637, P=0.011). But in case of VAS, there was no significant difference between VAS and duration of tinnitus.ConclusionAmong total 15 patients with catastrophic intractable chronic tinnitus, eight patients showed some improvement in symptoms after 1 Hz rTMS. rTMS can be considered management modality for intractable tinnitus even with distress as severe as catastrophic stage
    corecore