• Tuberculosis and Respiratory Diseases
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• 제40권3호
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• pp.267-273
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• 1993

연구배경 : Airway resistance 측정시 panting 방법은 비정상적인 호흡패턴으로 환자에 따라서는 수행이 어렵고 quiet breathing 방법은 더욱 생리적인 호흡상태하에서 측정이 가능하다. 과거에는 주로 panting을 이용하였으나 최근에는 quiet breathing을 이용하는 추세로 본 연구에서는 panting 및 quiet breathing시에 airway resistance를 측정하여 이를 비교하였다. 방법 : 정상대조군 및 호흡기질환군을 대상으로 유량기량곡선을 측정하고, body plethysmograph를 이용하여 airway resistance를 quiet breathing과 panting시에 각각 측정하였다. 결과: 1) Quiet breathing과 panting시 측정한 airway resistance는 높은 상관관계를 보였다(Raw tot; 0.887, Raw 0.5; 0.921, p<0.05). 2) Panting시 quiet breathing에 비하여 Raw tot는 21.2%. Raw 0.5는 22.1%의 감소율을 보였으며, Inspiratory와 expiratory Resistance의 측정이 가능하였던 경우 Raw insp은 29.3%, Raw exp은 40.6%의 감소율을 보였다. 3) Panting시 airway resistance의 감소율은 호흡기질환군보다 대조군에서 더 컸다. 4) Panting시 specific airway conductance가 유의하게 증가되었으므로 airway resistance의 감소는 thoracic gas volume의 차이와는 관련이 없었다. 5) Panting시 quiet breathing에 비하여 airway resistance가 감소하지 않는 환자는 비교적 airway resistance가 커서 panting을 잘 수행하지 못하는 환자로 추정된다. 결론 : Airway resistance 측정시 환자의 수행능력에 따라 quiet breathing 혹은 panting 방법을 이용할 수 있으나 panting시 quiet breathing보다 결과가 약 20% 감소됨을 고려하여야 하며, 정상군 및 폐질환군에서 panting보다 quiet breathing이 airway resistance를 측정하는 더 좋은 방법으로 생각된다.

• 대한방사선기술학회지:방사선기술과학
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• 제39권1호
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• pp.51-57
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• 2016

뇌 자기공명영상(Magnetic Resornance Imaging; MRI)에서 검사 중 발생되는 소음을 줄이기 위한 기법으로 경사 파형을 변경한 Quiet $T_2$-weighted Turbo Spin-Echo(이하 Q-$T_2$)와 일반적으로 사용되는 $T_2$-weighted Turbo Spin-Echo(이하 $T_2$) 영상의 소음수준 및 영상의 질을 비교하여 그 유용성을 알아보고자 하였다. 3.0T MR 기기로 뇌 MR 검사를 받은 60명(남자 29명, 여자 31명, 평균 연령 60.1세)의 환자를 대상으로 하였다. Q-$T_2$와 $T_2$ 각각의 영상에서 소음 및 심박동수를 측정하였다. 정량적 분석은 Q-$T_2$와 $T_2$의 SNR, CNR, SIR 값을 측정한 뒤 독립표본 T검정을 이용하여 통계적 분석을 하였다. 정성적 분석은 Q-$T_2$와 $T_2$의 전체적인 영상의 질에 대하여 육안으로 평가하였다. 평가는 5점 척도로서 우수(excellent) 5점, 양호(good) 4점, 보통(fair) 3점, 불량(poor) 2점, 평가불가(unacceptable) 1점으로 평가하였다. Q-$T_2$와 $T_2$ 검사 중 평균소음과 peak소음은 Q-$T_2$가 기존 $T_2$에 비해 각각 $15dB_A$, $10dB_A$ 감소하였다. 또한 각각의 검사 중 120초 동안 심박동수의 평균값은 Q-$T_2$에서 더 낮은 값으로 나타났지만 통계적인 유의성은 없었다. 정량적 분석의 결과 CNR과 SIR은 유의한 차이가 없었으며, SNR은 Q-$T_2$가 더 낮은 평균값을 보임으로서 유의한 차이를 보였다(p<0.05). 정성적 분석은 59개의 Q-$T_2$와 $T_2$ 영상의 질이 동일하게 우수(excellent) 5점으로 평가되었으며, 1개의 영상에서 모션 아티팩트로 인해 양호(good) 4점으로 평가되었다. Q-$T_2$는 기존의 $T_2$와 같이 검사시간 및 진단의 정확도는 동일하지만 소음을 효과적으로 감소시킬 수 있으며, 이로인하여 환자 편의를 향상시킬 수 있을 것으로 사료된다.

• Journal of Astronomy and Space Sciences
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• 제39권4호
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• pp.159-167
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• 2022

Because of the small number of spacecraft available in the Earth's magnetosphere at any given time, it is not possible to obtain direct measurements of the fundamental quantities, such as the magnetic field and plasma density, with a spatial coverage necessary for studying, global magnetospheric phenomena. In such cases, empirical as well as physics-based models are proven to be extremely valuable. This requires not only having high fidelity and high accuracy models, but also knowing the weakness and strength of such models. In this study, we assess the accuracy of the widely used Tsyganenko magnetic field models, T96, T01, and T04, by comparing the calculated magnetic field with the ones measured in-situ by the GOES satellites during geomagnetically disturbed times. We first set the baseline accuracy of the models from a data-model comparison during the intervals of geomagnetically quiet times. During quiet times, we find that all three models exhibit a systematic error of about 10% in the magnetic field magnitude, while the error in the field vector direction is on average less than 1%. We then assess the model accuracy by a data-model comparison during twelve geomagnetic storm events. We find that the errors in both the magnitude and the direction are well maintained at the quiet-time level throughout the storm phase, except during the main phase of the storms in which the largest error can reach 15% on average, and exceed well over 70% in the worst case. Interestingly, the largest error occurs not at the Dst minimum but 2-3 hours before the minimum. Finally, the T96 model has consistently underperformed compared to the other models, likely due to the lack of computation for the effects of ring current. However, the T96 and T01 models are accurate enough for most of the time except for highly disturbed periods.

• Journal of Astronomy and Space Sciences
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• 제21권2호
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• pp.93-100
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• 2004

We have investigated characteristic solar wind dynamics associated with relativistic electron events at geosynchronous orbit. Most of the events for April, 1999 through December, 2002 are found to be accompanied by a prolonged solar quiet period which is characterized as low solar wind density, weak interplanetary magnetic field (IMF), and fast alfvenic fluctuations in IMF $B_z$. In a typical relativistic event, electron fluxes begin to increase by orders of magnitude when solar wind parameters drop to low values (e.g., $n_{sw}∼5 cm^{-3}$ and ｜$B_{IMF}$∼5 nT) after sharp peaks. Then the elevated electron fluxes stay at the high level during the solar quiet period. This observation may suggest the following scenario for the occurrence of a geosynchronous relativistic event: (ⅰ) Quiet solar winds can yield a stable and more dipole-like magnetospheric configurations in which the geosynchronous orbit locates well inside the trapping boundary of the energetic electrons. (ⅱ) If a large population of MeV electrons are generated (by whatever acceleration process(es)) in the inner magnetosphere, they can be trapped and effectively accumulated to a high intensity. (ⅲ) The high electron flux can persist for a number of days in the geosynchronous region as long as the solar wind dynamics stays quiet. Therefore the scenario indicates that the occurrence of a relativistic event would be a result of a delicate balance between the effects of electron acceleration and loss. In addition, the sensitive dependence of a relativistic event on the solar wind conditions makes the prediction of solar wind variability as important as understanding of electron acceleration processes in the forecast of a relativistic event.

• 한국운동역학회지
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• 제20권4호
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• pp.479-486
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• 2010

The purpose of this study was to determine the effects of high-heeled shoe on the quiet standing and gait balance. Twenty women (mean height: $161.6{\pm}3.3\;cm$, mean body mass: $53.8{\pm}6.3\;kg$, mean age: $23.8{\pm}2.7$ yrs..) who were without history or complain of lower limb pain took part in this study. They were asked to stand quietly on a force platform for 30 sec and walk on it at their preferred walking speed (mean speed $3.14{\pm}0.5\;km/hr$.) with wearing three different high-heeled shoe, 3, 7, 9 cm high for collecting data. Data were randomly recorded to collect two trials for quiet standing and five trials for walking The parameters to have been analyzed for comparison between three conditions of the height of high-heeled shoe were COP(Center of Pressure) range, COP velocity, sway area, and free moment on the static balance and COP range, COP velocity, and free moment on the dynamic balance. In this study, high-heel height affected on the COP range and velocity in the ante-posterior direction during walking, dynamic balance, but didn't affect on the quiet standing, static balance.

• 아동학회지
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• 제38권2호
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• pp.219-232
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• 2017

Objective: The purpose of this study was to investigate the relationships among mothers' play beliefs, children's gender and home play frequency, and their preferences for three types of play. Methods: Totally 256 mothers of 5-year-olds participated in the survey in metropolitan area. Data were analyzed with t-test, Pearson's correlations, and stepwise multi-regression using SPSS 22.0. Results: First, boys and girls showed little difference in their home play experiences. Boys preferred active and rough play, while girls preferred quiet play. Second, mothers' play beliefs and children's home play frequency had partial correlations with children's play preferences. Third, predictors of children's play preferences were influenced by the types of play. Children's gender and mothers' play beliefs affected children's preference for active play. Only gender explained children's preference for rough play. Finally, children's gender, home play frequency, and mothers' play beliefs influence children's preference for quiet play. Conclusion: In conclusion, gender is an important factor of children's play preferences, and mothers' play beliefs and children's home play frequency affect their preferences for a specific type of play.

• 대한의용생체공학회:의공학회지
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• 제28권5호
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• pp.628-635
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• 2007

We studied the effect of vibratory stimulations of different leg muscles, tibialis anterior(TA) and triceps surae(TS), and plantar zones in ten healthy subjects during 1) quiet standing, 2) forward lean of body, 3) backward lean of body, 4) right lean of body, and 5) left lean of body. The experiments were performed on the force platform. The effect of vibration were measured by monitoring the area of COP(Center of pressure) sway. The subjects wore a vibratory stimulation system on foot and ankles and were given the instruction not to resist against the applied perturbations. The results show that all vibratory stimulations to lower limb muscles and plantar zones reduced the COP sway area. This reduction of the COP sway area occurred also in partial vibratory stimulations during quiet standing. In forward lean of body, vibratory stimulations to TA reduced the COP sway area. During backward lean of body, vibratory stimulations to TS reduced the COP sway area. When the subject was tilted right, vibratory stimulations to left plantar zone reduced the COP sway area. During left lean of body, vibratory stimulations to right plantar zone reduced the COP sway area. Thus, the influence of vibratory stimulations to leg muscle and plantar zones differed significantly depending on the lean of body. We suggest that the vibration stimuli from leg muscles and plantar zones could be selectively used to help maintaining postural balance stable.

• Journal of Astronomy and Space Sciences
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• 제22권4호
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• pp.431-440
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• 2005

K 지수는 특정 지역에서의 지자기 변동을 나타내는 지수로서 3시간마다 결정된다. K 지수를 결정하는 알고리즘은 태양복사의 규칙적인 일변화(Sq)를 결정하는 방법에 따라 다양하다. 그 중에서 FMI 알고리즘은 K 지수를 구하고자 하는 날과 그 전 후의 1일 자료를 포함한 총 3일 동안의 지자기 수평성분(H, D) 측정 자료를 사용하여 태양복사의 규칙적인 일변화(Sq)를 구한다. 그러나 이 알고리즘은 K 지수를 구하고자 하는 날로부터 1일 후까지의 측정 자료가 필요하기 때문에 실시간으로 K 지수를 구하는 경우에는 어려움이 있다. 본 연구에서는 준실시간으로 K 지수를 구하기 위해 미국 우주환경예보센터(NOAA/SEC)에서 제공하는 과거의 전지구적 지자기 K지수(Planetary K index: Kp)를 검색하여 최근의 Kp지수가 모두 3 이하인 지자기 활동이 조용한 날을 찾고 그 날의 지자기측정 자료를 FMI 알고리즘의 3일치 입력 자료로 사용함으로써 준실시간 K 지수를 구하는 방법을 고안하였다. 이러한 방법을 검증하기 위해 우리는 2003년 1년 동안 한국지질자원연구원에서 운용하는 경주 지자기 관측소의 FLARE+ 시스템으로 측정된 자료를 사용하고 우리의 준실시간 결정 방법을 적용하여 K 지수를 구하고 이를 일반적인 FMI 알고리즘으로 구한 K지수와 서로 비교하였다. 그 결과, 우리의 방법으로 결정된 K 지수는 일반적인 방법으로 구한 K 지수와 잘 일치하였다. 또한 준실시간 결정 방법으로 구한 K 지수를 일본 Kakioka 관측소에서 결정한 K 지수와 비교한 결과 그 상관지수(R)가 0.81 정도로 높음을 확인하였다. 본 연구의 결과는 향후 한반도 지역에서의 K 지수 변동을 준실시간으로 모니터링 하는데 활용될 수 있을 것으로 기대된다.

• 한국소음진동공학회논문집
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• 제17권3호
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• pp.207-212
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• 2007

Community noise has been great concerned in public. The traffic noise in seoul, especially has been growing awareness for the quiet living environment. In this paper, the effect on the noise barrier in order to reduce highway noise near on the street has been examined. First barriers have been evaluated at 5 locations in the city. The evaluation is performed before and after construction, with the reference point which does not affected on road traffic volume. Then, noise reducers mounted on the harriers also have been examined. the result shows that it reduces noise level by $3{\sim}3.5dB(A)$ with a standard deviation of 2.8 dB(A).

• Child Health Nursing Research
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• 제5권3호
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• pp.281-291
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• 1999

The purpose of this study was to compare the sleep characteristics between the prone and the supine position in healthy newborns. The 48 newborns were observed in the prone position and the supine position respectively on the 2nd day after birth. The data were collected from January to May, 1999. The state of a newborn was classified and categorized to 6 states (deep sleep. light sleep, drowsy, quiet alert, active alert, crying) by Barnard. The movements of eyes, face and extremities, pulse and arterial oxygen were observed and recorded continuously from the start of sleep after feeding until the time of being woken for the next feeding by a trained nurse The data was analyzed by using paired t-test. The results of this study were as follows; 1. There was no significant difference in the length of sleeping time between the prone and the supine position. 2. There was no significant difference in the length and frequencies of each states(deep sleep, light sleep, drowsy, quiet alert, active alert, crying) between the prone and the supine position But the frequency of light sleep in the supine position was significantly higher than that of the prone position. 3 There was no significant difference In the numbers or eyes movements between the prone and the supine sleep position. But the amount of facial and extremity movement in the supine position was significantly higher than those in the prone position 4. There was no significant difference in the arterial oxygen content between the prone and the supine sleep position. 5. There was no significant difference in the heart rates between the prone and the supine sleep position. The above results indicated that the newborns in the prone Position moved less and slept deeper than those in the supine position. though there was no difference in the length of sleep or arterial oxygen content between the prone and the supine sleep Position. But. Nurses and mothers should consider the relationship between the sleep Position and SIDS suggested by previous researches. The infant's 'awakening' during sleep is a normal process and rather valuable because it can provide an opportunity to promote a stronger relationship between mother and baby. So, It is suggested that the supine sleep position is better than the prone sleep position for infants.