1,904 research outputs found

    An application of LANDSAT multispectral imagery for the classification of hydrobiological systems, Shark River Slough, Everglades National Park, Florida

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    Multivariant hydrologic parameters over the Shark River Slough were investigated. Ground truth was established utilizing U-2 infrared photography and comprehensive field data to define a control network which represented all hydrobiological systems in the slough. These data were then applied to LANDSAT imagery utilizing an interactive multispectral processor which generated hydrographic maps through classification of the slough and defined the multispectral surface radiance characteristics of the wetlands areas in the park. The spectral response of each hydrobiological zone was determined and plotted to formulate multispectral relationships between the emittent energy from the slough in order to determine the best possible multispectral wavelength combinations to enhance classification results. The extent of each hydrobiological zone in slough was determined and flow vectors for water movement throughout the slough established

    Immersive training for movement sequences: The use of 360° video technology to provide poomsae training in Taekwondo

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    Background: The use of video technology is an established method of training. As an extended video format, 360° videos expand the potential of conventional videos with immersive and interactive design possibilities and combine conventional video technology with immersive technologies in a resource-saving manner. In sports, 360° videos can be used as tactical training tools to support reflection and analysis and to illustrate movements. In particular, 360° videos can be used to create a recorded authentic learning environment to support observational, multi-perspective training. Approach: This paper presents the use of 360° video training for the observation and imitation of movement sequences in poomsae training in taekwondo (or kata training in karate), using the example of the Taegeuk II Jang poomsae. The successive four-step concept can not only be applied to poomsae training in Taekwondo, but can also be transferred to other predefined movement forms and choreographies. Purpose: By using playback media with different degrees of immersion, the movement sequence can be observed, imitated, and followed in successive steps to enable the feeling of participating in a digital training group. Conclusions: The possible applications of 360° video technology in sports are versatile and offer new, immersive possibilities for simple and accessible training design. Training processes that are predominantly done through observational and imitative learning can be accompanied or shifted to home training with the presented 360° video training concept. In particular, 360° videos are suitable for reflective and observational training due to the multiple perspectives provided by the 360° view, which remain to be evaluated

    Word Processors with Line-Wrap: Cascading, Self-Organized Criticality, Random Walks, Diffusion, Predictability

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    We examine the line-wrap feature of text processors and show that adding characters to previously formatted lines leads to the cascading of words to subsequent lines and forms a state of self-organized criticality. We show the connection to one-dimensional random walks and diffusion problems, and we examine the predictability of catastrophic cascades.Comment: 6 pages, LaTeX with RevTeX package, 4 postscript figures appende

    Avalanche statistics of sand heaps

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    Large scale computer simulations are presented to investigate the avalanche statistics of sand piles using molecular dynamics. We could show that different methods of measurement lead to contradicting conclusions, presumably due to avalanches not reaching the end of the experimental table.Comment: 6 pages, 4 figure

    Anomalous Transport in Conical Granular Piles

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    Experiments on 2+1-dimensional piles of elongated particles are performed. Comparison with previous experiments in 1+1 dimensions shows that the addition of one extra dimension to the dynamics changes completely the avalanche properties, appearing a characteristic avalanche size. Nevertheless, the time single grains need to cross the whole pile varies smoothly between several orders of magnitude, from a few seconds to more than 100 hours. This behavior is described by a power-law distribution, signaling the existence of scale invariance in the transport process.Comment: Accepted in PR

    Self-organized criticality in a rice-pile model

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    We present a new model for relaxations in piles of granular material. The relaxations are determined by a stochastic rule which models the effect of friction between the grains. We find power-law distributions for avalanche sizes and lifetimes characterized by the exponents τ=1.53±0.05\tau = 1.53 \pm 0.05 and y=1.84±0.05y = 1.84 \pm 0.05, respectively. For the discharge events, we find a characteristic size that scales with the system size as LμL^\mu, with μ=1.20±0.05\mu = 1.20 \pm 0.05. We also find that the frequency of the discharge events decrease with the system size as LμL^{-\mu'} with μ=1.20±0.05\mu' = 1.20 \pm 0.05.Comment: 4 pages, RevTex, multicol, epsf, rotate (sty files provided). To appear Phys. Rev. E Rapid Communication (Nov or Dec 96

    High-temperature extraction of lignocellulosic bio-crude by supercritical carbon dioxide

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    Supercritical carbon dioxide extraction was utilized for the fractionation of a pinewood derived hydrothermal liquefaction bio-crude. The experiments were performed at temperature 120 ºC and at pressure levels that correspond to CO2 density of 500, 615 and 730 kg/m3. Extraction yields of 34 to 49 % were achieved, which increased with increasing solvent density. Density was reduced for all extracts (2-10 %) while the H/C ratio increased when compared to the bio-crude. Low boiling point components such as ketones, 1-ring aromatic hydrocarbons and low molecular weight fatty acids were extracted preferentially (K-values up to 11). 1-ring phenols and benzenediols were enriched in the extracts as well (K-values 1-3). Heavy hydrocarbons and long chain fatty acids were extracted at the later stages of extraction when the lighter components were depleted.</p

    Universality classes for rice-pile models

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    We investigate sandpile models where the updating of unstable columns is done according to a stochastic rule. We examine the effect of introducing nonlocal relaxation mechanisms. We find that the models self-organize into critical states that belong to three different universality classes. The models with local relaxation rules belong to a known universality class that is characterized by an avalanche exponent τ1.55\tau \approx 1.55, whereas the models with nonlocal relaxation rules belong to new universality classes characterized by exponents τ1.35\tau \approx 1.35 and τ1.63\tau \approx 1.63. We discuss the values of the exponents in terms of scaling relations and a mapping of the sandpile models to interface models.Comment: 4 pages, including 3 figure
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