• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.521-524
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• 2001

신호 대 잡음비가 매우 낮은 수중 음원을 탐지하기 위해서는 많은 센서를 갖는 견인 배열 시스템을 운용하여야 한다. 그러나 이러한 경우 수백 미터에 이르는 배열을 견인함이 끌고 다닐 때 파도와 같은 해수면의 움직임과 견인선의 기동 형태에 따라 원하는 배열 형태를 항상 유지할 수 없다. 그러므로 본 논문에서는 실제 수 중 환경에서 견인되는 배열의 왜곡된 형태를 시간적으로 뿐만 아니라 공간적으로 통합된 센서의 움직임 근거로 한 상관 형태를 잘 표현한 ""Paidoussis"" 방정식을적용하여 이 방정식의 간단화된 형태인 수차 모형(Water pulley)배열을 협대역 목표물 탐지에 이용하였다. [1][2][8] 수차 모형 구조의 배열을 이용하여 사상 기법을 적용하면 수차 모형의 왜곡 특성으로 인해 센서간 간격이 비균일성을 가지는 가상의 선형 배열이 형성되어 진다. 본 논문에서는 사상 기법에 의해 생성된 가상의 선형 배열을 토대로 합성 어패처 방식의 일종인 FFTSA(Fast Fourier Transform Synthetic Aperture) 기법을 이용하여 센서 배열의 입사각 추정 성능에 중대한 영향을 부여하는 코히어런스 주기에 따른 추정 성능의 변화 및 견인함의 이동 경로 변화에 따른 변동 경로 주기에 따른 성능 변화를 분석하였다.

• Journal of Astronomy and Space Sciences
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• v.5 no.1
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• pp.19-30
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• 1988

The existence of the j-type collision periodic orbit is examined on the condition of mass ratio 0.9878449 and Jacobian constant 2.9∼3.4. Using the Birckhoff's regularization method and the 5th order Runge-Kutta variable step-sized numerical roution introduced by Fehlberg (1968). we test their periodicities. As the results, 4 j-type collision orbits and 5 peculiar orbits are represented. There are good agreements in this collision orbits with the relationship between the period and the shape of orbit proposed by Pinotsis Zikides(1984).

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.2
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• pp.123-135
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• 2012

Purpose: It is essential to minimize the movement of tumor due to respiratory movement at the time of respiration controlled radiotherapy of non-small cell lung cancer patient. Accordingly, this Study aims to evaluate the usefulness of restricted respiratory period by comparing and analyzing the treatment plans that apply free and restricted respiration period respectively. Materials and Methods: After having conducted training on 9 non-small cell lung cancer patients (tumor n=10) from April to December 2011 by using 'signal monitored-breathing (guided- breathing)' method for the 'free respiratory period' measured on the basis of the regular respiratory period of the patents and 'restricted respiratory period' that was intentionally reduced, total of 10 CT images for each of the respiration phases were acquired by carrying out 4D CT for treatment planning purpose by using RPM and 4-dimensional computed tomography simulator. Visual gross tumor volume (GTV) and internal target volume (ITV) that each of the observer 1 and observer 2 has set were measured and compared on the CT image of each respiratory interval. Moreover, the amplitude of movement of tumor was measured by measuring the center of mass (COM) at the phase of 0% which is the end-inspiration (EI) and at the phase of 50% which is the end-exhalation (EE). In addition, both observers established treatment plan that applied the 2 respiratory periods, and mean dose to normal lung (MDTNL) was compared and analyzed through dose-volume histogram (DVH). Moreover, normal tissue complication probability (NTCP) of the normal lung volume was compared by using dose-volume histogram analysis program (DVH analyzer v.1) and statistical analysis was performed in order to carry out quantitative evaluation of the measured data. Results: As the result of the analysis of the treatment plan that applied the 'restricted respiratory period' of the observer 1 and observer 2, there was reduction rate of 38.75% in the 3-dimensional direction movement of the tumor in comparison to the 'free respiratory period' in the case of the observer 1, while there reduction rate was 41.10% in the case of the observer 2. The results of measurement and comparison of the volumes, GTV and ITV, there was reduction rate of $14.96{\pm}9.44%$ for observer 1 and $19.86{\pm}10.62%$ for observer 2 in the case of GTV, while there was reduction rate of $8.91{\pm}5.91%$ for observer 1 and $15.52{\pm}9.01%$ for observer 2 in the case of ITV. The results of analysis and comparison of MDTNL and NTCP illustrated the reduction rate of MDTNL $3.98{\pm}5.62%$ for observer 1 and $7.62{\pm}10.29%$ for observer 2 in the case of MDTNL, while there was reduction rate of $21.70{\pm}28.27%$ for observer 1 and $37.83{\pm}49.93%$ for observer 2 in the case of NTCP. In addition, the results of analysis of correlation between the resultant values of the 2 observers, while there was significant difference between the observers for the 'free respiratory period', there was no significantly different reduction rates between the observers for 'restricted respiratory period. Conclusion: It was possible to verify the usefulness and appropriateness of 'restricted respiratory period' at the time of respiration controlled radiotherapy on non-small cell lung cancer patient as the treatment plan that applied 'restricted respiratory period' illustrated relative reduction in the evaluation factors in comparison to the 'free respiratory period.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.208-213
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• 2009

본 논문에서는 Tree-ring width 지표자료, 태양흑점수, 남방진동지수(SOI) 및 지구온도 아노말리 자료와의 비교를 통하여 서울지점 측우기 강우량 자료의 정확도를 가늠해 보았다. 그리고 한반도 인근지역의 Tree-ring width 지표자료와의 비교를 통하여 과거 동북아시아 기후변화 상관성과 변화특성을 파악해 보았다. 분석 결과 측우기 강우량 자료는 다른 비교분석 대상 자료들과 경향성과 변화심도가 매우 잘 일치하고 있어 상당한 신뢰성을 가지고 있음이 확인되었다. 그리고 한반도 주변 6개 지점의 Tree-ring width 지표자료와의 비교분석결과, 장기적으로 동북아시아 기후는 시공간적으로 밀접한 상관을 가지고 변화하고 있으며 그 변화에는 장주기적인 재현성이 존재한다는 점을 알 수 있었다. 그러나 1960년 이후의 기후변화 특성은 통계적인 거동특성이나 변화폭이 과거의 재현사상의 한계를 넘지는 않으나 과거와는 다른 경향성과 불규칙성을 보여주고 있으며 재현주기도 짧아지고 있어 과거와는 다르게 나타나는 것으로 분석되었다. 과거자료에 근거한 본 연구의 결과는 동북아시아 기후변화 장기 예측에 있어 유용하게 이용될 수 있을 것으로 판단된다.

• Journal of Wetlands Research
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• v.21 no.4
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• pp.365-373
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• 2019

In this study, we investigated the effect of wave height in coastal areas using discrete wavelet transform in Taehwa river basin in Ulsan. Through the decomposition result of tide data using daubechies level 7 wavelet and Curve Fitting Function, we confirmed that detail components of d₃ and d₄ were semidiurnal and diurnal components and approximation component(a₆) was the long period of lunar fortnight constituent. The decomposed tide data in six level was divided into tide component with periodicity and wave component with non-periodicity using autocorrelation function and fourier transform. Finally, we confirmed that the tide component is consisted 66% and wave component is consisted 34%. So, we quantitatively assessed the effect of wave on coastal areas. The result could be used for coastal flood risk management considering the effect of wave.

• Korean Journal of Ecology and Environment
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• v.45 no.3
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• pp.340-346
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• 2012

The relationships between environmental factors and the dynamics of the microcrustacean community, including planktonic or epiphytic cladocerans and copepods, were studied at Upo Wetlands from 2001 to 2010. Among 10 identified cladoceran taxon, epiphytic cladocerans (Alona, Camptocercus, Simocephalus, Diaphanosoma, Sida) and planktonic cladocerans (Bosmina, Ceriodaphnia, Daphnia, Moina, Scapholeberis) showed distinctive patterns in appearance throughout the year. Overall, epiphytic cladocerans were more abundant during the aquatic plant development season (May to Nov.), planktonic cladocerans were similarly distributed throughout the seasons, but showed a lower density than epiphytic cladocerans. The seasonal changes in copepods abundance showed a similar seasonal pattern when compared to epiphytic cladocerans. Planktonic cladocerans showed no significant relationship to rainfall and physico-chemical factors, while epiphytic cladocerans exhibited a distinct relationship with rainfall and water temperature (n=120, p<0.01), and a negative relationship with pH and conductivity (n=120, p<0.05). Among the epiphytic cladocerans, the Alona and Diaphanosoma showed a distinctive correlation with environmental factors, and their density was affected by rainfall and water temperature (n=120, p<0.01). Copepods had a positive relationship with rainfall (n=120, p<0.01) and water temperature (n=120, p<0.05). In conclusion, changes in rainfall and water temperature can affect the seasonal changes of microcrustacean community and abundance in Upo Wetlands.

• Korean Journal of Remote Sensing
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• v.32 no.2
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• pp.195-200
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• 2016

Water vapor leading various scale of atmospheric circulation and accounting for about 60% of the naturally occurring warming effect is important climate variables. Using the Total Precipitable Water (TPW) from Moderate Resolution Imaging Spectroradiometer (MODIS) operating on both Terra and Aqua, we study long-term Variation of TPW and define relationship among TPW and climatic parameters such as temperature and precipitation to quantitatively demonstrate the impact on climate change over East Asia focusing on the Korea peninsula. In this study, we used linear regression analysis to detect the correlation of TPW and temperature/precipitation and harmonic analysis to analyze changeable aspects of periodic characteristics. A result of analysis using linear regression analysis between TPW and climate elements, TPW shows a high determination coefficient ($R^2$) with temperature and precipitation (determination coefficient between TPW and temperature: 0.94, determination coefficient between TPW anomaly and temperature anomaly: 0.8, determination coefficient between TPW and precipitation: 0.73, determination coefficient between TPW anomaly and precipitation anomaly: 0.69). A result of harmonic analysis of TPW and precipitation of two-year to five-year cycle, amplitude contribution ratio of 3.5-year cycle are much higher and two phases are similar in 3.5-year cycle.

• Tuberculosis and Respiratory Diseases
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• v.46 no.5
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• pp.628-635
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• 1999

Background : Maximal expiratory flow rate is determined by the size of airway, elastic recoil pressure and the collapsibility of airway in the lung. The obstruction of expiratory flow is one of the major functional impairments of emphysema, which represents COPD. Nevertheless, expiratory narrowing of upper airway may be recruited as a mechanism for minimizing airway collapse, and maintaining lung volume and hyperinflation by an endogenous positive end-expiratory pressure in patients with airflow obstruction. We investigated the physiologic role of trachea in respiration in emphysema. Method : We included 20 patients diagnosed as emphysema by radiologic and physiologic criteria from January to August in 1997 at Seoul Municipal Boramae Hospital. Chest roentgenogram, high resolution computed tomography(HRCT), and pulmonary function tests including arterial blood gas analysis and body plethysmography were taken from each patient. Cross-sectional area of trachea was measured according to the respiratory cycle on the level of aortic arch by HRCT and calibrated with body surface area. We compared this corrected area with such parameters of pulmonary function tests as $PaCO_2$, $PaO_2$, airway resistance, lung compliance and so on. Results : Expiratory cross-sectional area of trachea had significant correlation with $PaCO_2$ (r=-0.61, p<0.05), $PaO_2$ (r=0.6, p<0.05), and minute ventilation (r=0.73, p<0.05), but inspiratory cross-sectional area did not (r=-0.22, p>0.05 with $PaCO_2$, r=0.26, p>0.05 with $PaO_2$, and r=0.44, p>0.05 with minute ventilation). Minute ventilation had significant correlation with tidal volume (r=0.45, p<0.05), but it had no significant correlation with respiratory frequency (r=-0.31, p>0.05). Cross-sectional area of trachea had no significant correlation with other parameters of pulmonary function including $FEV_1$, FVC, $FEV_1$/FVC, peak expiratory flow, residual volume, diffusing capacity, airway resistance, and lung compliance, whether the area was expiratory or inspiratory. Conclusion : Cross-sectional area of trachea narrowed during expiration in emphysema, and its expiratory area had significant correlation with $PaCO_2$, $PaO_2$, and minute ventilation.

• The Journal of the Convergence on Culture Technology
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• v.6 no.2
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• pp.183-190
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• 2020

This study was designed to investigate the current state of lens wearing and care, and to investigate eye discomfort according to the care method. Data of 209 female college students wearing lenses for more than 1 year were analyzed using the SPSS / WIN 22.0 program. 40.2% of female students wear lenses every day and 97.1% wear all day. However, only 45.4% of students washed it daily, and only 17.7 % used protein remover during wash, which resulted in poor management. 98.1% of students complained of discomfort due to the lens, and the Ocular Surface Index (OSDI) scored 42.88 ± 15.25, which was classified as a severe dry eye and threatened eye health. Therefore, it is necessary to improve students' awareness of lens management, and periodical lens inspection and management education are needed.

• Proceedings of the KSRS Conference
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• 2009.03a
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• pp.121-125
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• 2009

농업과 환경분야에서 토양 상태를 신속하고 주기적으로 모니터링하는 것에 대한 관심이 높아지고 있다. 토양의 특성을 측정하는 기존의 화학분석 방식은 분석의 정밀도, 시료의 수, 분석항목 등에 따라 시간, 인력, 비용적 소모가 커진다. 최근에는 식품, 농업, 환경 분야에서 신속하고 비파괴적 분석 방법으로 가시 근적외선 분광학을 도입하고 있다. 가시 근적외선 영역(VNIR, 400-2400 nm)에는 다양한 물질의 고유한 흡수분광형태가 존재한다는 이론적 토대로부터 물질의 정성 정량적 분석이 가능하다고 알려져 있다. 본 연구에서는 VNIR 분광 스펙트럼으로부터 Al, organic carbon (OC), clay, silt, sand, CEC (Cation exchange capacity), CEC/clay 등의 토양 특성을 정량하고자 하였다. 농경지에서 채취한 94개 토양시료를 기존의 화학분석 방법으로 분석하고 실내에서 VNIR 스펙트럼을 측정하였다. 스펙트럼은 원시형태와, 1차, 2차 도함수로 변환된 형태 모두 partial least square regression (PLSR) 모델에 적용하였다. PLSR에 의한 토양특성 추정식은 RMSE, $R^2$, SDE, RPD 값을 이용하여 검증하였다. Al, OC, silt, sand 함량에 대해서는 통계적으로 유의한 수준의 추정값을 산출하였고, clay와 CEC/clay에 대해 추정한 값은 실측값과 약한 상관성을 나타내었다. 이러한 분광학적인 추정 기법은 영상을 이용한 정성 정량분석에 활용될 수 있을 것으로 사료된다.