• Title/Summary/Keyword: Velocity Change

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Research on the Variation of Deposition & Accumulation on the Shorelines using Ortho Areial Photos (수치항공사진을 이용한 해안선 침퇴적변화에 관한 연구)

  • Choi, Chul-Uong;Lee, Chang-Hun;Oh, Che-Young;Son, Jung-Woo
    • Journal of Korean Society for Geospatial Information Science
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    • v.17 no.3
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    • pp.23-31
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    • 2009
  • The border of the shorelines in a nation is an important factor in determining the border of a national territory, but Korea's shorelines are rapidly changing due to the recent rise in sea level from global warming and growth-centered economic policy over the decades of years. This research was done centering on the areas having well-preserved shorelines as they naturally are and other areas having damaged shorelines in their vicinities due to artificial structures at the two beaches located at the neighboring areas and having mutually homogeneous ocean conditions with each other. First, this research derived the shorelines using the aerial photographies taken from 1947 until 2007 and revised the tidal levels sounding data obtained from a hydrographical survey automation system consisting of Echosounder[Echotrac 3100] and Differential Global Positioning System[Beacon]by using topographical data and ships on land obtained by applying post-processing Kinematic GPS measuring method. In addition, this research evaluated the changes and dimensional variations for the last 60 years by dividing these determined shorelines into 5 sections. As a result, the Haewundae Beach showed a total of 29% decrease rate in dimension as of the year 2007 in comparison with the year 1947 due to a rapid dimensional decline centering on its west areas, while the dimension of the Gwanganri Beach showed an increase in its dimension amounting to a total of 69% due to the decrease in flow velocity by artificial structures built on both ends of the beach-forming accumulation; thus, it was found that there existed a big difference in deposition & accumulation tendency depending on neighboring environment in spite of the homogeneous ocean conditions.

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The Change of ${\alpha}$-motor neuron excitability in Spastic Stroke Patients by Pre-tibia Muscle Isometric Contraction (전경골근 등척성 수축에 의한 경직성 뇌졸중 환자의 비복근 ${\alpha}$-운동 신경원 흥분 변화)

  • Kim, Jong-Soon;Lee, Hyun-Ok;Ahn, So-Youn
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.11 no.1
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    • pp.11-28
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    • 2005
  • Spasticity has been defined as "a motor disorder characterized by a velocity-dependent increased in tonic stretch reflexes with exaggerated tendon jerks, resulting from hyperexcitability of the stretch reflex, as one components of the upper motorneuron syndrome". Spasticity is one of the common symptoms of stroke patients and frequently interferes with the motor functions such as gait, posture and activities of daily living. Therefore, its management is becoming a major issue in physical therapy. The purpose of this study was to determined the effects of reciprocal inhibition by isometric contraction of pre-tibia muscle on spasticity in hemiplegic patients through Hoffmann reflex. The subjects were consisted 45 patients who had hemiplegia due to stroke. All subjects randomly assigned to 3 group: manual reciprocal inhibition program group(manual group), neuromuscular electrical stimulation group(NMES group) and control group. The manual group received voluntary isometric contraction of pre-tibia muscle. The NMES group received neuromuscular electrical stimulation on tibialis anterior. The control group was not received any therapeutic intervention. Before and after experiments, Hoffmann reflex, M-wave and Modified Ashworth scale was measure in all patients. The data of 30 patients who complete experimental course were statistically analysed. Modified Ashworth scale were significantly decreased after experiment in manual group(p<.01). The Hmax/Mmax ratios were significantly decreased after experiment in manual group(p<.o1). There were no statistical difference between pre-test and post-test with modified Ashworth scale in NMES group(p>.01). There were no statistical difference between pre-test and post-test with Hmax/Mmax ratios in NMES group(p>.01). There were no statistical difference between pre-test and post-test with modified Ashworth scale in control group(p>.01). There were no statistical difference between pre-test and post-test with Hmax/Mmax ratios in control group(p>.01). The present results revealed that reciprocal inhibition which produced by voluntary isometric contraction of pre-tibia muscle can be reduce spasticity of gastrocnemius. Therefore, reciprocal inhibition is useful to improve functional activities in hemiplegic patient. Further study should be done to analyse the effects of intervention duration of reciprocal inhibition, appropriate muscle contraction, optimal time to apply the reciprocal inhibition in more long period.

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Differential Horizontal Stress Ratio for Danyang Limestone with Vertical Transversely Isotropy (횡적등방성 특성을 갖는 단양 석회암의 수평응력차비 고찰)

  • Jang, Seonghyung;Hwang, Seho;Shin, Jehyun;Kim, Tae Youn
    • Geophysics and Geophysical Exploration
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    • v.20 no.4
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    • pp.207-215
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    • 2017
  • To develope shale play which is one of unconventional energy resources, horizontal drilling and hydraulic fracturing are necessary and those are applied to the place where the differential horizontal stress ratio (DHSR) is low. The differential horizontal stress ratio is generally calculated by the minimum and maximum horizontal stress, but it is also calculated from dynamic elastic constants and anisotropic parameters. In this study we analyzed anisotropic properties through the core samples from Danyang limestone and calculated DHSR. The three types of core samples shaped in three directions (vertical, parallel and 45 degree to bedding) were used for laboratory test. We measured P-, S-wave velocities, and density and then calculated dynamic elastic constants, compliance and DHSR. According to the results of the core sample analysis the calculated DHSR is 0.185. Thomsen parameters of the Danyang limestone used in this study are characterized by the P- and S-wave velocities varying along the bedding symmetry axis. It is observed that the DHSR value is more affected by the change in compliance value than the Poisson's ratio. It is necessary to measure SH-wave velocity for more correct petrophysical properties.

Analysis on Characteristics of Orographic Effect about the Rainfall Using Radar Data: A Case Study on Chungju Dam Basin (레이더 자료를 이용한 호우의 산지효과 특성 분석: 충주댐 유역을 대상으로)

  • Ku, Jung Mo;Ro, Yonghun;Kim, Kyoungjun;Yoo, Chulsang
    • Journal of Korea Water Resources Association
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    • v.48 no.5
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    • pp.393-407
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    • 2015
  • This study analyzed the characteristics of orographic effect using radar data for the Chungju dam basin. First, independent rainfall events were selected by applying the IETD (Interevent Time Definition) and rainfall threshold. Among those independent rainfall events, rather strong events were selected to decide the occurrence condition of orographic effect. Also, the average reflectivity was calculated for the entire period and for the period of storm center, and the change in reflectivity was analyzed by comparing the average reflectivity to that in the mountain area. Important rainfall factors were selected and applied to the logistic regression model to decide the occurrence condition of orographic effect. Summarizing the results is as follows. First, evaluation of the radar data along the passing line of a storm showed the increase of radar reflectivity in the mountain area. Second, the result of logistic regression analysis showed that the orographic effect in the Chungju Dam Basin mostly occurred when the rainfall intensity was higher than 4 mm/hr, the storm velocity was lower than 4 km/hr, and the approach angle was $90^{\circ}{\pm}5^{\circ}$.

Seismic First Arrival Time Computation in 3D Inhomogeneous Tilted Transversely Isotropic Media (3차원 불균질 횡등방성 매질에 대한 탄성파 초동 주시 모델링)

  • Jeong, Chang-Ho;Suh, Jung-Hee
    • Geophysics and Geophysical Exploration
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    • v.9 no.3
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    • pp.241-249
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    • 2006
  • Due to the long tectonic history and the very complex geologic formations in Korea, the anisotropic characteristics of subsurface material may often change very greatly and locally. The algorithms commonly used, however, may not give sufficiently precise computational results of traveltime data particularly for the complex and strong anisotropic model, since they are based on the two-dimensional (2D) earth and/or weak anisotropy assumptions. This study is intended to develope a three-dimensional (3D) modeling algorithm to precisely calculate the first arrival time in the complex anisotropic media. Considering the complex geology of Korea, we assume 3D TTI (tilted transversely isotropy) medium having the arbitrary symmetry axis. The algorithm includes the 2D non-linear interpolation scheme to calculate the traveltimes inside the grid and the 3D traveltime mapping to fill the 3D model with first arrival times. The weak anisotropy assumption, moreover, can be overcome through devising a numerical approach of the steepest descent method in the calculation of minimum traveltime, instead of using approximate solution. The performance of the algorithm developed in this study is demonstrated by the comparison of the analytic and numerical solutions for the homogeneous anisotropic earth as well as through the numerical experiment for the two layer model whose anisotropic properties are greatly different each other. We expect that the developed modeling algorithm can be used in the development of processing and inversion schemes of seismic data acquired in strongly anisotropic environment, such as migration, velocity analysis, cross-well tomography and so on.

Study on masticatory pattern of adult having anterior cross bite (전치부 반대교합 성인의 저작양상에 관한 연구)

  • Sohn, Byung-Wha;Yu, Hyung-Seog;Park, Jong-Jin
    • The korean journal of orthodontics
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    • v.27 no.1
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    • pp.35-44
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    • 1997
  • mastication is basically regulated by central pattern regulalor(CPG) of brain system, target organ output from CPG is modulated by oral sensory feedback, anterior cross bite pattern infuluence the feedback mechanism and change muscle activity and jaw movement. The purpose of this study was to investigate differnce anterior cross bite group from normal group, the selected sample groups were 30 normal patient, 30 anterior cross bite patient. EMG and EGN of Biopak system were used for this study The following results were obtained 1 In resting slate of mandible, anterior cross-bite showed the higher muscle activities in all the muscle.(exception:left digastric muscle) than normal group. 2. In clenching state, No significant difference in muscle activities of normal group and anterior cross bite group was noticed 3. In swallowing state Normal group showed the higher muscle activities in left and right masseter muscle, right posterior temporal muscle. 4. In maximum opening and closing velocity, normal group showed the higher value than anterior cross-bite. 5. In the mean value of the maximum opening,the maximum anterior posterior movemenl from centric-occlusion, the lateral deviation from centric occclusion, normal group showed the higher value than anterior cross-bite group.

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Seismic reflection survey in a tidal flat: A case study for the Mineopo area (갯벌 지역에서의 탄성파 탐사: 민어포 조간대 지역의 사례)

  • Jou Hyeong-Tae;Kim Han-Joon;Lee Gwang-Hoon;Choi Dong-Lim;Kim Min-Ji;Cho Hyun-Moo
    • 한국지구물리탐사학회:학술대회논문집
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    • 2002.09a
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    • pp.67-84
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    • 2002
  • A shallow high-resolution seismic reflection survey was carried out at the Mineopo tidal flat on the western coast of Korea. The purpose of the survey was to investigate shallow sedimentary structure of the tidal (fat associated with the recent sea level change. A total of 795 shots were generated at 1 m interval from a 5-kg hammer source and recorded on 48 channels of 100 Hz geophones along two mutually perpendicular profiles. The water-saturated ground condition resulted in suppressed ground rolls by significantly decreasing rigidity. In addition, seismic velocities over 1500 m/s provided easy segregation of reflected arrivals from lower velocity noise. As a consequence, seismic sections were created that are high in resolution and signal to noise ratio as well. The stack sections show that the tidal flat consists of 5 sedimentary sequences above acoustic basement. Although deposition is largely characterized by the transgressive sedimentary facies resulting from sea level rise, erosional surfaces are well-resolved within the sequences.

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The Scientific Analysis of Aged' Shoe for Health Promotion (노인 건강증진용 신발의 운동과학적 효과분석)

  • Jin, Young-Wan;Kwak, Yi-Sub
    • Journal of Life Science
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    • v.21 no.9
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    • pp.1336-1345
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    • 2011
  • The purpose of this study was to analyze and compare the effects of exercise science of shoes for Aged' health promotion. Kinematic and kinetic data were collected using cinematography and the Zebris system (Zebris Emed Sensor Platform, GR-DVL9800) to analyze pressure of foot and ground reaction force. Subjects recruited were 20 healthy elderly men. They walked at 1.36m/sec velocity wearing type A (domestic), type B (foreign) and walking shoes (A company). One-way ANOVA was used to analyze statistics. The results were as following: no significant differences were observed in gait variables among the three groups (p<0.05). There was a significant difference in max pronation angle of heels examined among the three groups (p<0.05). There were no significant differences in kinetic variables (ground reaction force and max pressure) among the three groups (p<0.05). A physiology study was performed to analyze the effects of walking with shoes with silver added to them on percent body fat, resting metabolic rate and energy expenditure. Sixty adults males were recruited from the public health center. They were divided into four groups. C: control group (n=20), EY: elderly Y group (n=20), and EO: elderly O group (n=20). The results of this study were as follows: percent body fat was decreased following each exercise period, however, not all the groups showed a significant difference. The change of resting metabolic rate was significantly increased in HI (high intensity) and LI (low intensity) periods in the C and EY groups. However, there was no significant difference in the EO group. The mean energy expenditure during and after exercise were significantly lowered in all periods compared to the control group.

Void Ratio Evaluation of Unsaturated Soils by Compressional and Shear Waves (압축파와 전단파를 이용한 불포화토의 간극비 산정)

  • Byun, Yong-Hoon;Cho, Se-Hyun;Yoon, Hyung-Koo;Choo, Yun-Wook;Kim, Dong-Su;Lee, Jong-Sub
    • Journal of the Korean Geotechnical Society
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    • v.28 no.12
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    • pp.41-51
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    • 2012
  • Soils are commonly unsaturated in the near surface. The stiffness of soils is affected by the amount of air and water. The objective of this study is to evaluate the porosity of the unsaturated soils by using the elastic waves including compressional and shear waves. The elastic waves are measured at different degrees of saturation by controlling the matric suction. Thus, the unsaturated soils are characterized at different levels of the matric suction. Shear and compressional waves are measured by using the bender elements and the piezo disk elements, respectively. Both transducers are installed on the walls of the rectangular cell. The unsaturated soils are prepared by using uniform size sands and silts. Test results show that both compressional and shear wave velocities change according to the matric suction. The elastic modulus, the shear modulus, and the Poisson's ratio are estimated based on the measured elastic wave velocities. In addition, the void ratio of the unsaturated soils estimated using elastic wave velocities matches well with the volume based void ratio. This study demonstrates that the elastic waves can be effectively used for the characterization of unsaturated soils.

Numerical experiments for the changes of currents by reclamation of land in Kwangyang Bay (매립으로 인한 광양만의 유동변화 수치실험)

  • 추효상
    • Journal of Environmental Science International
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    • v.11 no.7
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    • pp.637-650
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    • 2002
  • This study presents an investigation of the changes of the currents in Kwangyang Bay due to the construction of harbor, reclamation and coastal developments. Currents were simulated by the numerical experiments with a diagnostic multi-level model and using the seasonal oceanographic data of temperature, salinity and ocean current. The values of kinetic and potential energies for the currents were calculated in cases of three topographical changes; before coastal developments, the existing state and after completion of the development project in Kwangyang Bay. The changes of currents due to the coastal developments are as follow; Kinetic energies of tide induced residual currents and wind driven currents decreased by 35~40 percent and 5 percent respectively, however those of density currents increased by 10 percent since the decrease of the coastal areas. Kinetic energy of residual currents including tide induced residual currents, density currents and wind driven currents reduced by 10 percent compared with before the coastal developments. Decrease of current velocity was greatest in summer. Therefore, in summer it was assumed that the Kwangyang Bay is more easily polluted by stratification and decrease of residual current than before the coastal developments carried out.