• 대한토목학회논문집
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• 제38권6호
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• pp.793-800
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• 2018

본 연구는 최근 빈번히 발생하는 홍수재해에 대비하고 안정적인 치수대책 수립을 위하여 공학적 판단에 근거한 하천의 적정 설계빈도 결정방안을 제시하였다. 지방하천의 설계빈도는 하천의 중요도 및 지역특성에 따라 최소 50년부터 최대 200년까지 설정되고 있으나, 적용범위가 넓어 하천의 지형적, 치수적 특성을 제대로 반영하지 못하는 실정이다. 본 연구에서는 지방하천의 적정 설계빈도를 결정하기 위하여 7개의 평가인자(시가화 침수면적, 유역면적, 형상계수, 하도경사, 수계 및 하천차수, 배수영향구간, 이상강우 발생빈도)에 대하여 베이즈 이론을 적용하여 가중치를 산정하였다. 또한, 기후변화를 고려한 홍수피해잠재능을 산정하였고, 시군구별 잠재능을 구분하여 적정 설계빈도를 결정하였다. 충청남도 382개 지방하천에 대하여 현행 설계빈도의 적정성을 평가하였다. 382개의 현행 하천설계빈도보다 상향되는 하천은 65개 하천으로 상대적으로 시가화 침수면적이 크게 산정되고 홍수피해잠재능이 큰 지역의 하천이며, 하향되는 하천은 169개로 분석되었다.

• 한국의류학회지
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• 제46권6호
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• pp.1058-1073
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• 2022

Big data analytics and social media have shifted the way fashion trends are dictated. Fashion as a medium for expressing gender has created new concepts of masculinity in popular culture, where men are increasingly depicted in a softer style. In this study, we analyzed 2,879 menswear collections over a 10-year period from Vogue US to uncover key menswear trends. Using Semantic Network Analysis (SNA) on Orange3, we were able to quantitatively analyze how contemporary menswear designers interpreted diversified trends of masculinity on the runway. Frequency and degree centrality were measured to weigh the significance of trend keywords. "Jacket (f = 3056; DC = 0.80), shirt (f = 1912; DC = 0.60) and pant (f = 1618; DC = 0.53)" were among the most prominent keywords. Our results showed that soft masculine keywords, e.g., "lace, floral, and pink" also appeared, but with the majority scoring DC = < 0.10. The findings provide an insight into key menswear trends through frequency, degree centrality measurements, time-series analysis, egocentric, and visual semantic networks. This also demonstrates the feasibility of using text analytics to visualize design trends, concepts, and patterns for application as an ideation tool for academic researchers, designers, and fashion retailers.

• 한국수자원학회논문집
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• 제31권4호
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• pp.469-481
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• 1998

한강 인도교 지점의 1918년부터 1992년 간의 총 68년의 연최대 홍수량 계열 자료를 수집하여 지점빈도해석을 실시하였다. 3변수 대수정규분포, 제1형 극치분포, 제3형 극치분포 및 Pearson type-III분포에 의한 확률 홍수량의 값이 대체로 부합하는 결과를 보여주었으며, 100년 및 200년 빈도 홍수량의 값은 각각 35,500 m3/sec 및 39,000 m3/sec로 계산되었다. 또한 유역내에 설치되어 있는 각종 댐의 홍수조절효과를 고려하여 댐이 존재하는 경우를 기준으로 홍수량 계열을 수정한 후 빈도해석을 실시한 결과 빈도 홍수량은 33,500 m3/sec 및 37,500 m3/sec 로 계산되었다. 200년 홍수량 37,500 m3/sec는 현 한강하류부 고시유량인 37,000 m3/sec와 비교하면 비슷한 값이며, 기후 변화에 따른 홍수량의 증가성향을 감안하면 현 고시유량의 고수가 바람직 할 것으로 보인다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2001
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• pp.11-18
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• 2001

A close examination of the step calibrations for STS-2 seismometers installed by KMA has been done to deduce the response parameters of those instrument including angular corner frequency, damping factor and coil constant factor. A non-linear least square inversion method has been apple iud to estimate these parameters. The estimated parameters coincide with the manufactory specification with less than 1% error. This method will be extended near- future to deduce the response parameters for SS-1 short period seismometer.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.633-636
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• 2007

The objective of this study is to measure backscattering coefficients of paddy rice using L, C, X-bands scatterometer system during a rice growth period. The measurement was conducted at an experimental field located in National Institute of Agricultural Science and Technology (NIAST), Suwon, Korea. The rice cultivar was a kind of Japonica type, called Chuchung. The scatterometer system consists of dual-polarimetric square horn antennas, HP8720D vector network analyzer (20MHz ${\sim}$ 20GHz), RF cables, and a personal computer that controls frequency, polarization and data storage. The scatterometer system is calibrated using a calibration kit (3.5mm, 85052D). The backscattering coefficients were calculated by applying radar equation for the measured at incidence angles between $20^{\circ}$ and $60^{\circ}$ for four polarization (HR, VV, HV, VH), respectively, and compared with rice growth data such as plant height, stem number, biomass, dry weight and LAI that were collected at time of each scatterometer measurement simultaneously.

• 전기학회논문지
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• 제58권7호
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• pp.1393-1397
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• 2009

A high-speed wavelength swept laser, which is based on oscillation characteristics of a fiber Fabry-Perot tunable filter, is described. The laser is constructed by using a semiconductor optical amplifier, a fiber Fabry-Perot tunable filter, and 3.348 km fiber ring cavity. The wavelength sweeps are repeatatively generated with the repetition period of 61 kHz which is the first parallel oscillation frequency of the Fabry-Perot tunable filter for the low power consumption. Mode-locking is implemented by 3.348 km fiber ring cavity for matching the fundamental of cavity roundtrip time to the sweep period. The wavelength tuning range of the laser is 87 nm(FWHM) and the average output power is 1.284 mW.

• International Journal of Naval Architecture and Ocean Engineering
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• 제2권1호
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• pp.34-38
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• 2010

Field investigations have been carried out in two 60-day stages on the surf beat low frequency waves in Anzali port, one of the main commercial ports in Iran, located in southwest coast of the Caspian Sea. The characteristics of significant water waves were measured at three metering stations in the sea, one at the entrance of the port and three in the basin. The measured data were inspected to investigate the surf beat negative effects on the tranquility of the port. Using field measurements and complementary numerical modeling, the response of the basin to the infra-gravity long waves was inspected for a range of wave frequencies. It was concluded that the water surface fluctuations in the port is strongly related to the incident wave period. The long waves with periods of about 45s were recognized as the worst cases for water surfaceperturbation in the port. For wave periods higher than the mentioned range, the order of fluctuation was generally low.

• Wind and Structures
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• 제12권5호
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• pp.401-412
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• 2009

A method is applied for the estimation of structural damage of tall slender structures using natural frequency and displacements measurements by GPS. The relationship between the variation in the global stiffness matrix (or in the stiffness of each finite element) and the change in the natural frequencies of the structure is given. In engineering practice the number of frequencies which can be derived by GPS measurement of long-period structures will be equal to one, two or three first natural frequencies. This allows us in initial studies to detect damage with frequency changes based on forward methods in which the measured frequencies are compared with the predicted analytical data. This idea, of health monitoring from possible changes to natural frequencies, or from a statement of excessive displacements is applied to the Stuttgart TV Tower.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.991-992
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• 2008

When we heard the sound of waves, we can feel stable and comfortable. I'm going to analysis the cause of comfortableness. The period is about three seconds when we breathed in relaxed state. The frequencies which in waves sound and meditation or heavy sleep are alike. Furthermore we can see that frequency is distributed in all over band width like white noise. In this paper, we confirm the fact that waves sound give comfortableness to us with Frequency Following Response.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1187-1189
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• 2004

This paper presents a boost circuit topology driving in high - frequency. It solves the problem which arised from hard-switching in high-frequency using a period of resonant circuit and operating under the principle of ZCS turn-on and ZCZVS turn-off commutation schemes. In the existing circuit, it has the high voltage stress in free-wheeling diode. But in the proposed circuit, it has voltage stress which is lower than voltage stress of existing circuit with modifing a location of free-wheeling diode. In this paper, it explained the circuit operation of each mode and the waveform of each mode. Also the experiment result compares the existing voltage stress of free-wheeling diode with the proposed voltage stress of that.