• 한국운동역학회지
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• 제22권3호
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• pp.325-332
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• 2012

This study aimed to analyze the effects of external load between male and female on angular velocity, moment, and absorbed energy of the lower-extremity joints during drop landing. The study subjects were 9 male($mass=70.82{\pm}4.64kg$, $height=1.71{\pm}0.04m$, $age=24.5{\pm}1.84years$), 9 female($mass=50.14{\pm}4.09kg$, $height=1.61{\pm}0.03m$, $age=23.6{\pm}2.62years$), without any serious musculoskeletal, coordination, balance, or joint/ligament problems for 1 year before the study. The angular velocity, flexion/extension and abduction/adduction moments, and absorbed energy of the lower-extremity joints were compared between the men and women during drop landing under 4 different conditions of external load(0%, 8%, 16%, and 24%) by using two-way repeated ANOVA(p < .05). The women landed with a greater peak angular velocity of the ankle joint, greater peak inversion moment, and lower peak hip-extension moment than the men did, under all 4 conditions. Additionally, the landing characteristics of the women were distinct from those of the men; the women showed a greater peak knee-adduction moment and greater absorbed energy of the knee joint. These differences indicate that anterior cruciate ligament(ACL) strain was greater in the women than in the men and therefore, women may be at a higher potential risk for noncontact injuries of the ACL with an increase in external load.

• Current Optics and Photonics
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• 제2권1호
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• pp.15-22
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• 2018

To measure atmospheric temperature, water vapor, and aerosol simultaneously, an efficient multi-function Raman lidar using an ultraviolet-wavelength laser has been developed. A high-performance spectroscopic box that utilizes multicavity interference filters, mounted sequentially at small angles of incidence, is used to separate the lidar return signals at different wavelengths, and to extract the signals with high efficiency. The external experiments are carried out for simultaneous detection of atmospheric temperature, water vapor, and aerosol extinction coefficient in Beijing, under clear and hazy weather conditions. The vertical profiles of temperature, water vapor, and aerosol extinction coefficient are analyzed. The results show that for an integration time of 5 min and laser energy of 200 mJ, the mean deviation between measurements obtained by lidar and radiosonde is small, and the overall trend is similar. The statistical temperature error for nighttime is below 1 K up to a height of 6.2 km under clear weather conditions, and up to a height of 2.5 km under slightly hazy weather conditions, with 5 min of observation time. An effective range for simultaneous detection of temperature and water vapor of up to 10 km is achieved. The temperature-inversion layer is found in the low troposphere. Continuous observations verify the reliability of Raman lidar to achieve real-time measurement of atmospheric parameters in the troposphere.

• Journal of Electrical Engineering and Technology
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• 제1권3호
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• pp.396-405
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• 2006

The visual analysis of buried channel (Be) devices such as buried channel MOSFETs and CCDs (Charge Coupled Devices) is investigated to give better understanding and insight for their electrical behaviours using a 3-dimensional (3-D) numerical simulation. This paper clearly demonstrates the capability of the numerical simulation of 'EVEREST' for characterising the analysis of a depletion mode MOSFET and BC CCD, which is a simulation software package of the semiconductor device. The inverse threshold and punch-through voltages obtained from the simulations showed an excellent agreement with those from the measurement involving errors of within approximately 1.8% and 6%, respectively, leading to the channel implanted doping profile of only approximately $4{\sim}5%$ error. For simulation of a buried channel CCD an advanced adaptive discretising technique was used to provide more accurate analysis for the potential barrier height between two channels and depletion depth of a deep depletion CCD, thereby reducing the CPU running time and computer storage requirements. The simulated result for the depletion depth also showed good agreement with the measurement. Thus, the results obtained from this simulation can be employed as the input data of a circuit simulator.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.65-68
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• 2007

FORMOSAT-3 was launched in April of 2006. It consists of six low earth orbit (LEO) satellites that will be eventually deployed to an orbit at 800 km height. Its scientific goal is to utilize the radio occultation (RO) signals to measure the bending angles when the GPS signals transect the atmosphere. The bending angle is then used to infer atmospheric parameters, including refractivity, temperature, pressure, and relative humidity fields of global distributions through inversion schemes and auxiliary information. The expected number of RO events is around 2500 per day, of which 200 events or so fall into the polar region. Consequently, the FORMOSAT-3 observations are expected to play a key role to improve our knowledge in the weather forecasting and space physics research in the polar region. In this paper, we use temperature profiles retrieved from FORMOSAT-3 RO observations to study the climatology of gravity wave activity in the polar region. FORMOSAT-3 can provide about 200 RO observations a day in the polar region, much more than previous GPS RO missions, and, hence, more detailed climatology of gravity wave activity can be obtained.

• 천문학회보
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• 제39권1호
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• pp.69.1-69.1
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• 2014

We perform an MHD simulation combined with observed vector field data to clarify an eruptive dynamics in the solar flare. We first extrapolate a 3D coronal magnetic field under a Nonlinear Force-Free Field (NLFFF) approximation based on the vector field, and then we perform an MHD simulation where the NLFFF prior to the flare is set as an initial condition. Vector field was obtained by the Soar Dynamics Observatory (SDO) at 00:00 UT on February 15, which is about 90 minutes before the X2.2-class flare. As a result, the MHD simulation successfully shows an eruption of strongly twisted lines whose values are over one-turn twist, which are produced through the tether-cut magnetic reconnection in strongly twisted lines of the NLFFF. Eventually, we found that they exceed a critical height at which the flux tube becomes unstable to the torus instability determining the condition that whether a flux tube might escape from the overlying field lines or not. In addition to these, we found that the distribution of the observed two-ribbon flares is similar to the spatial variance of the footpoints caused by the reconnection of the twisted lines being resided above the polarity inversion line. Furthermore, because the post flare loops obtained from MHD simulation well capture that in EUV image taken by SDO, these results support the reliability of our simulation.

• 한국운동역학회지
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• 제31권2호
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• pp.113-118
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• 2021

Objective: The purpose of this study was to investigate differences of landing strategy between people with or without chronic ankle instability (CAI) during double-leg drop landing. Method: 34 male adults participated in this study (CAI = 16, Normal = 18). Participants performed double-leg drop landing task on a 30 cm height and 20 cm horizontal distance away from the force plate. Lower Extremities Kinetic and Kinematic data were obtained using 8 motion capture cameras and 2 force plates and loading rate was calculated. Independent samples t-test were used to identify differences between groups. Results: Compared with normal group, CAI group exhibits significantly less hip internal rotation angle (CAI = 1.52±8.12, Normal = 10.63±8.44, p = 0.003), greater knee valgus angle (CAI = -6.78±5.03, Normal = -12.38 ±6.78, p = 0.011), greater ankle eversion moment (CAI = 0.0001±0.02, Normal = -0.03±0.05, p = 0.043), greater loading Rate (CAI = 32.65±15.52, Normal = 18.43±10.87, p = 0.003) on their affected limb during maximum vertical Ground Reaction Force moment. Conclusion: Our results demonstrated that CAI group exhibits compensatory movement to avoid ankle inversion during double-leg drop landing compared with normal group. Further study about how changed kinetic and kinematic affect shock absorption ability and injury risk in participants with CAI is needed.

• 한국운동역학회지
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• 제33권1호
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• pp.34-44
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• 2023

Objective: The purpose of this study was to examine the effects of increasing running speed on human stability by comparing the Lyapunov Exponent (LyE) and Coefficient of Variation (CV) methods, with the goal of identifying key variables and uncovering new insights. Method: Fourteen adult males (age: 24.7 ± 6.4 yrs, height: 176.9 ± 4.6 cm, weight: 74.7 ± 10.9 kg) participated in this study. Results: In the CV method, significant differences were observed in ankle (flexion-inversion/eversion; p < .05) and hip joint (internal-external rotation; p < .05) movements, while the center of mass (COM) variable in the coronal axis movements showed a significant difference at the p < .001 level. In the LyE method, statistical differences were observed at the p < .05 level in knee (flexion-extension), hip joint (internal-external rotation) movements, and COM across all three directions (sagittal, coronal, and transverse axis). Conclusion: Our results revealed that the stability of the human body is affected at faster running speeds. The movement of the COM and ankle joint were identified as the most critical factors influencing stability. This suggests that LyE, a nonlinear time series analysis, should be actively introduced to better understand human stabilization strategies.

• 한국지구과학회지
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• 제41권3호
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• pp.222-237
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• 2020

2018년 8월 6일 영동지역에서 강한 대류 세포에 의해 천둥과 번개를 동반한 집중호우(강릉: 93 mm hr^-1)가 발생했다. 집중호우 사례의 특성을 조사하기 위하여 COMS 위성의 구름 산출물 자료, 상하층 종관 일기도, ECMWF 재분석 자료, 라디오존데 자료를 이용하였다. 분석결과, 상층의 차고 건조한 공기가 동해상(영동지역)으로 유입되면서 상대적으로 중·하층에 따뜻하고 습한 공기와 만나 대기의 불안정을 만들고 대류운이 급격하게 발달하면서 단시간에 많은 강수가 내렸다. COMS 위성의 구름 운정 온도가 약 -65℃ 이상, 구름 광학 두께는 약 20-25 이상의 높은 값을 보일 때 강수량은 10 mm hr^-1 이상으로 나타났다. 따라서 강수량은 구름 내의 수분 양 그리고 구름의 키와 밀접한 관련성을 가지는 것을 확인할 수 있었다. 라디오존데 자료의 연직 분석에서는 상하층 간의 연직 바람 쉬어가 크게 나타났다. 약 700 hPa 고도에서는 역전층이 나타나면서 상층과 하층간의 상당온위의 차이를 유발하여 대기불안정을 더욱 강화시켰으며 구름층은 고도 약 13 km 이상으로 발달하는 것을 확인할 수 있었다. 이러한 결과는 ECMWF 재분석 자료의 연직 분석에서도 확인할 수 있었다.

• 한국토양비료학회지
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• 제17권2호
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• pp.108-113
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• 1984

수도(水稻)의 생육기간중(生育期間中) 군락내(群落內) 미세기상특성(微細氣象特性)의 변화(變化)를 보기 위하여 1982년도(年度)에는 서광벼를 $3.3m^2$당(當) 50, 80, 110주(株)로 재식밀도(栽植密度)를 달리하였고, 1983년도(年度)에는 서광벼와 추청벼를 $3.3m^2$당(當) 80주(株)로 재배(栽培)하였다. 본(本) 시험(試驗)에서는 군락내(群落內)의 기온(氣溫), 수온(水溫) 및 지온(地溫)의 수직분포(垂直分布)와 일사량(日射量) 및 엽면적지수(葉面積指數)와의 관계(關係)를 중심(中心)으로 검토분석(檢討分析)하였으며 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 생육초기(生育初期)의 수도(水稻)의 군락내기온(群落內氣溫)은 이앙후(移秧後) 30일(日)에는 밀식구(密植區)(110주(株)/$3.3cm^2$)가 소식구(疎植區)(50주(株)/$3.3m^2$)보다 $1{\sim}1.5^{\circ}C$정도 높았고, 이앙후(移秧後) 60일(日)에는 역전되는 경향을 보였으며 이앙후(移秧後) 90일(日)에는 밀식구군락(密植區群落) 기온(氣溫)이 소식구(疎植區)보다 $3{\sim}4^{\circ}C$ 높았다. 한편 생육초기(生育初期)에는 수면(水面)에 가까운 10cm층위(層位)의 기온(氣溫)이 30cm층위(層位)보다 높았으나 이앙후(移秧後) 60일이후(日以後)는 10cm층위(層位)가 30cm층위(層位)보다 낮아졌다. 2. 군락내(群落內) 최고온도(最高溫度) 출현시각(出現時刻)은 생육초기(生育初期)에는 대기기온(大氣氣溫)과 비슷한 시각(時刻)인 연후(年後) 2~3시경(時)이었으나 군락(群落)이 번무(繁茂)함에 따라 일사강도(日射强度)가 가장 높은 정오(正午)에 접근(接近)하였다. 3. 군락내(群落內) 수온(水溫)이 군락내기온(群落內氣溫)보나 높은 시기(時期)는 집면적지수(集面積指數)가 4.6(추청벼)내지 5.2(서광벼)이하(以下)이고, 투광율(透光率)이 40% 이상(以上)인 때이었다. 4. 군락내광감소계수(群落內光減小係數)는 군락상부(群落上部)가 0.3~0.5, 하부(部)가 0.1내외(內外)이었다. 5. 시각별(時刻別) Albedo는 아침과 저녁에는 0.4 이상(以上)이었으나, 정오(正午)에는 0.25내외(內外)이었으며 태양고도(太陽高度)가 낮을 때는 잎이 만곡형(彎曲型)인 추청벼구(區)에서, 높을 때는 직립형(直立型)인 서광벼구(區)에서 낮았다.

• 대한간호학회지
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• 제30권5호
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• pp.1318-1332
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• 2000

The purpose of this study was to determine the effect of walk training on leg strength, flexibility, postural stability, balance and gait in home bound elderly women. Eighteen elderly women of the experimental group aged between 70 and 90 years image who have normal vision, hearing and Romberg test. They participated in the 12 week walk training. The subjects of the experimental group practiced walk training 3 times a week for during 12 weeks. During the 40 minute workout, the subjects practiced 5 minutes of warming-up exercises, 30 minutes of conditioning exercises and 10 minutes of a cool-down exercise. The intensity for the conditioning phase was determined by subject' heart rates, which ranged from 60% to 70% of age-adjusted maximum heart rates. The body composition, leg strength, flexibility, postural stability, balance and gait were measured prior to and after the experimental treatment. The body fat, lean body mass, leg strength (ankle dorsiflexor, plantarflexor, inversor and eversir, knee flexor, extensior), flexibility (range of motion of ankle dorsiflexion, plantarflexion, inversion and eversion), and postural stability of the experimental group were significantly greater than those of the control group. Duration of standing on the right foot and that of standing on the left foot of the experimental group was greater than that of the control group. Total balance scores of the experimental group were significantly higher than those of the control group. Among 13 items for balance, the scores of experimental group in balance with eyes closes, turning balance, sternal nudge, neck turning, one leg standing balance and back extension were higher than those of the control group. Total scores of gait of the experimental group were significantly higher than those of the control group following the walking training. Scores of experimental group in step height, step length and walk stance while walking among 9 items for gait were significantly higher than those of the control group. The results suggest that walk training can improve physical fitness for prevention in home bound elderly women.