• Title/Summary/Keyword: Spatial and Temporal Parameters

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A Study of Temporal Characteristics From Multi-Dimensional Precipitation Model (다차원 강우모형의 시간적인 특성 연구)

  • Kim, Sangdan;Yoo, Chulsang;Kim, Joong-Hoon;Yoon, Yong Nam
    • Journal of Korea Water Resources Association
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    • v.33 no.6
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    • pp.783-791
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    • 2000
  • A multidimensional representation for precipitation, given In the theory proposed by E. Waymire et al. (1984), is used for simulating rainfall in space and time. The model produces moving storms with realistic meso-scale meteorological features in time and space. The first- and second-order statistics derived from observed JX)int gauge data were used to estimate the model parameters based on the Nelder-Mead algorithm of optimization. Then twelve-year traces of rainfall intensities at fixed gage stations were generated at intervals of 1 hours. First- and second-order statistics are evaluated from the above series, which are used for estimating the parameters of one dimensional model of temporal rainfall at a point. As a result from the comparisons of one dimensional model parameters used observed and generated data from multidimensional model, we found that the multidimensional rainfall model generated visually realistic spatial patterns of rainfall as well as realistic temporal hyetographs of rainfall at a point. point.

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The Analysis of High Chlorophyll-a Concentration Patch in the North Marine Areas of East China Sea (동중국해 북부 해역의 엽록소 고농도 덩어리 분석)

  • Jeong, Jong-Chul
    • Journal of Environmental Impact Assessment
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    • v.23 no.3
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    • pp.220-226
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    • 2014
  • This study investigated temporal-spatial and variations in Geostationary Ocean Color Imager (GOCI) products of parameters total suspended solids (TSS) and chlorophyll-a in the North Marine Areas of East China Sea.GOCI data were collected daily from February 2012 to December 2012. The higher chlorophyll-a values were observed during the investigation period. The relatively large increase in TSS and chlorophyll-a at the sampling stations coupled with typhoon events during the summer rainy period. The abnormal chlorophyll-a concentration was mainly driven by meteorological factors such as typhoon and rainfall in the coastal areas of Jeju and the North Marine Areas of East China Sea. The abnormal high chlorophyll-a concentration at the majority of the coastal stations indicate eutrophication of coastal waters, especially Red tide. The events such as eutrophication and abnormal high chlorophyll-a concentration may potentially influence outbreak of Red Tide, detected with GOCI parameters.

FISS Observations of Shocks in the Solar Chromosphere

  • Chae, Jong-Chul;Park, Hyung-Min;Yang, Hee-Su;Park, Young-Deuk;Nah, Ja-Kyoung;Cho, Kyung-Suk;Jang, Bi-Ho;Ahn, Kwang-Su;Cao, Wenda;Goode, Philip R.
    • The Bulletin of The Korean Astronomical Society
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    • v.36 no.2
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    • pp.88.1-88.1
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    • 2011
  • Shocks are thought to be important in the dynamics and heating of the solar chromosphere. The observational determination of shock parameters, however, has been hardly done because of the difficulty of observation at a high spatial, temporal and spectral resolution, and the lack of an effective method of inferring physical parameters from spectral data. Our inversion of the spectral data of the $H{\alpha}$ and Ca II 854.2 nm lines simultaneously taken from an intranetwork area, produced temporal profiles of temperature as well as line-of-sight velocities, from which we infer that three-minute chromospheric oscillations prevailing in the upper chromosphere are in fact trains of strong shocks with a strength of about two and a propagation speed of 20 km s-1 that carry a mechanical energy flux of 500 W m-2 upward. Our result supports the notion that shocks dominate the heating of the upper chromosphere, and probably the corona as well, at least in intranetwork regions of the quiet sun.

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The Influence of Auditory-Feedback Device Using Wearable Air-Pressure Insole on Spatiotemporal Gait Symmetry in Chronic Hemplegia

  • Heo, Ji-Hun;Song, Changho;Jung, Sangwoo
    • Physical Therapy Rehabilitation Science
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    • v.10 no.3
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    • pp.311-319
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    • 2021
  • Objective: To investigate the effect of emphasized initial contact by using a wearable air-pressure insole to provide auditory-feedback with variations of maximum peak pressure (MPP) of the affected side on spatiotemporal gait parameters and gait symmetry of stroke patients Design: A cross-sectional study Methods: Eighteen stroke patients participated in this study. All subjects walked five trials using an air-pressure insole that provides auditory feedback with different thresholds set on the insole. First, subjects walked without any auditory feedback. Then, the MPP threshold on the affected side was set from 70% and increase threshold by 10% after each trial until 100%. They walked three times or more on the gait analyzer for each trial, and the average values were measured. Before starting the experiment, subjects measured body weight, initial gait abilities and affected side MPP without auditory feedback. Results: Temporal and spatial variables were significantly increased in trials with auditory feedback from air-pressure insole except for non-paralyzed single support time and spatial gait symmetry compared to trials without auditory feedback(p<0.05). Among the four different thresholds, the walking speed, unaffected side single support time, affected and unaffected side stride, and affected side step length were greatest at 80% threshold of maximum peak, while affected single support time, temporal gait symmetry, and unaffected step length were greatest at the maximum peak of 100% threshold. Conclusions: These results indicate that auditory feedback gait using air-pressure insoles can be an effective way to improve walking speed, single support time, step length, stride, and temporal gait symmetry in stroke patients.

Evaluation of Recurrent Neural Network Variants for Person Re-identification

  • Le, Cuong Vo;Tuan, Nghia Nguyen;Hong, Quan Nguyen;Lee, Hyuk-Jae
    • IEIE Transactions on Smart Processing and Computing
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    • v.6 no.3
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    • pp.193-199
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    • 2017
  • Instead of using only spatial features from a single frame for person re-identification, a combination of spatial and temporal factors boosts the performance of the system. A recurrent neural network (RNN) shows its effectiveness in generating highly discriminative sequence-level human representations. In this work, we implement RNN, three Long Short Term Memory (LSTM) network variants, and Gated Recurrent Unit (GRU) on Caffe deep learning framework, and we then conduct experiments to compare performance in terms of size and accuracy for person re-identification. We propose using GRU for the optimized choice as the experimental results show that the GRU achieves the highest accuracy despite having fewer parameters than the others.

The Effects of Insole Supporting Medial Longitudinal Arch while Walking in Spastic Cerebral Palsy with Pes Planus (안쪽 세로 발바닥 활을 지지한 인솔의 착용이 평발을 가진 경직성 뇌성마비 아동의 보행에 미치는 영향)

  • Kim, Sung Gyung;Ryu, Young Uk;Kim, Hyeong Dong
    • Journal of the Korean Society of Physical Medicine
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    • v.7 no.4
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    • pp.471-480
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    • 2012
  • PURPOSE: The object of the present study is to investigate the effects of the insole supporting medial longitudinal arch while walking in spastic cerebral palsy with pes planus. METHODS: Ten spastic bilateral cerebral palsy children with pes planus participated in this study. The insole were custom-made for the individual child. Muscle activity was measured by surface EMGs attached on tibialis anterior (TA), gastrocnemius (GA), vastus medialis oblique (VMO), biceps femoris long head (BF). temporal-spatial parameters such as velocity, step length, stride length, stance time, toe angle were collected while the subjects walked on the GAITRite system. RESULTS: The results of the present study were summarized as follows: 1. Muscle activities in mean EMGs while walking: Left VMO, Right TA, Left BF and GA revealed significant reductions after applying insole. 2. Muscle activities in peak EMGs while walking: Left TA and BF demonstrated reductions significantly after applying insole. 3. There were improvements in temporal-spatial gait parameters with insole: velocity, both step length, Right stride length and Right toe angle were increased(p<.05). CONCLUSION: Therefore the current study demonstrated that insole supporting the medial longitudinal arch would be effective on gait of the spastic cerebral palsy with pes planus.

Distribution Patterns of the Dominant Macrobenthos and the Benthic Environments on Subtidal Soft-bottom in Chonsu Bay, Korea (천수만 조하대 연성저질에 서식하는 저서동물 우점종의 분포 양상과 저서 환경)

  • Park Heung-Sik;Kang Rae-Seon;Lee Jae-Hac
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.39 no.spc1
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    • pp.214-222
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    • 2006
  • Dominant species of macrobenthos were analyzed based on differentiation of three distinct methods: the density based method, the biomass based method and LeBris method, by considering the frequency of occurrence using quantitative data collected over 5 years (1993-1998) at 21 stations in Chonsu Bay. Sedimentary environments as well as species composition and diversity showed the spatial and temporal distribution patterns. The ranks of dominant species as determined by the density based method were more similar to the results by the LeBris method than to those from the biomass based method. Considering the temporal variation, LeBris method were more efficient than any other methods for the determination of dominant species in Chonsu Bay. Lumbrineris longifolia, Theora fragilis, and Moerella jedoensis were recognized by all three methods. A one-way analysis of variance indicated spatial distributions patterns among most of the dominant species. These species showed positive correlations to sedimentary parameters such as mean grain size. However, T. fragilis and Paraprinospio pinnata showed the temporal patterns in their distribution, and were also correlated to the benthic environment, organic content and dissolved oxygen. Some dominant species, e.g., T. fragilis, S. scutata, G. gurjanovae proved to be useful benthic indicators based on the environmental variations determinated by long-term benthic ecological monitoring in Chonsu Bay.

GIS Application Model for Spatial Simulation of Surface Runoff from a Small Watershed(I) (소유역 지표유출의 공간적 해석을 위한 지리정보시스템의 응용모형(I) -격자 물수지 모형의 개발 및 적용-)

  • 김대식;정하우
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.37 no.3_4
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    • pp.23-33
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    • 1995
  • Geographic data which are difficult to handle by the characteristics of spatial variation and variety turned into a possibility to analyze with tlie computer-aided digital map and the use of Geographic Information System(GIS). The purpose of this study is to develop and apply a GIS application model (GISCELWAB) for the spatial simulation of surface runoff from a small watershed. This paper discribes the modeling procedure and the applicability of the cell water balance model (CELWAB) which calculates the water balance of a cell and simulates surface runoff of watershed simultaneously by the interaction of cells. The cell water balance model was developed to simulate the temporal and spatial storage depth and surface runoff of a watershed. The CELWAB model was constituted by Inflow-Outflow Calculator (JOC) which was developed to connect cell-to-cell transport mechanism automatically in this study. The CELWAB model requests detail data for each component of a cell hydrologic process. In this study, therefore, BANWOL watershed which have available field data was selected, and sensitivity for several model parameters was analyzed. The simulated results of surface runoff agreed well with the observed data for the rising phase of hydrograph except the recession phase. Each mean of relative errors for peak discharge and peak time was 0.21% and2.1 1% respectively. In sensitivity analysis of CELWAB , antecedent soil moisture condition(AMC) affected most largely the model.

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A Perspective on Radar Remote Sensing of Soil Moisture

  • Park, Sang-Eun
    • Korean Journal of Remote Sensing
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    • v.27 no.6
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    • pp.761-771
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    • 2011
  • The sensitivity of microwave scattering to the dielectric properties and the geometric structure of soil surfaces makes radar remote sensing a challenge for a wide range of environmental issues directly related to the condition of natural surfaces. Especially, the potential for retrieving soil moisture with a high spatial and/or temporal resolution represents a significant contribution to hydrological and ecological modeling. This paper aims to review the current state of the art in SAR technology and methodological issues towards the discovery of a new potential accurate monitoring of soil moisture changes. In this paper, important parameters or constraints significantly affect the sensitivity of the measurements to soil moisture, such as roughness statistics, spatial resolution, and local topography, are discussed to improve the applicability of SAR remote sensing techniques. This study particularly intends to discuss important notes for developing smart and reliable methods capable of retrieving geophysical information.

UNIFORMLY CONVERGENT NUMERICAL SCHEME FOR A SINGULARLY PERTURBED DIFFERENTIAL-DIFFERENCE EQUATIONS ARISING IN COMPUTATIONAL NEUROSCIENCE

  • DABA, IMIRU TAKELE;DURESSA, GEMECHIS FILE
    • Journal of applied mathematics & informatics
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    • v.39 no.5_6
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    • pp.655-676
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    • 2021
  • A parameter uniform numerical scheme is proposed for solving singularly perturbed parabolic partial differential-difference convection-diffusion equations with a small delay and advance parameters in reaction terms and spatial variable. Taylor's series expansion is applied to approximate problems with the delay and advance terms. The resulting singularly perturbed parabolic convection-diffusion equation is solved by utilizing the implicit Euler method for the temporal discretization and finite difference method for the spatial discretization on a uniform mesh. The proposed numerical scheme is shown to be an ε-uniformly convergent accurate of the first order in time and second-order in space directions. The efficiency of the scheme is proved by some numerical experiments and by comparing the results with other results. It has been found that the proposed numerical scheme gives a more accurate approximate solution than some available numerical methods in the literature.