• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1631-1635
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• 2011

To consider dynamic magnification effect at the static design stage, impact load factor is applied to design load. Current impact load factor adopted EUROCODE without verification while Japan suggested impact load factor including velocity of high-speed train throughout theoretical and experimental studies. On the purpose of evaluate current impact load factor, this study investigated the calculation of impact load factor from dynamic response of running train.

• Coupled systems mechanics
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• 제9권4호
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• pp.311-323
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• 2020

This paper deals with the effect of the mode shapes on the dynamic response of a multi-storey frame subjected to moving train loads which are modelled as loads of constant intervals with constant velocity using the finite element method. The multi-storey frame is modelled as a number of Bernoulli-Euler beam elements. First, the first few modes of the multi-storey frame are determined. Then, the effects of force span length to beam length ratio and velocity on dynamic magnification factor (DMF) are evaluated via 3D velocity-force span length to beam length ratio-DMF graphics and its 2D projections. By using 3D and 2D graphics, the directions of critical speeds that force the structure under resonance conditions are determined. Last, the mode shapes related to these directions are determined by the time history and frequency response graphs. This study has been limited by the vibration of the frame in the vertical direction.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2001년도 학술대회논문집
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• pp.59-64
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• 2001

Transient in an electrical system are generated by lightning and switching. This paper presents analysis of switching and lightning surge, and means of limiting the voltage magnification transient for high voltage power systems by using EDSA's EMTAP software package. One means of limiting the voltage magnification transient is to convert the end-user power factor correction banks to harmonic filters. An inductance in series with the power factor correction bank was used to decrease the transient voltage at the customer bus to acceptable levees. The interception of the impulse from the phase wire is fairly straight forward by properly installed surge arresters. The simulation shows that the addition of the surge arrester at the customer location can achieve a substantial reduction of the transient magnitude.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1636-1640
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• 2011

To consider dynamic magnification effect at the static design stage, impact factor is applied to design load. Current impact factor adopted EUROCODE without domestic verification through theoretical and experimental studies. This study evaluated impact factor of railway bridges from dynamic response under KTX running. Moving Average Method was applied to calculate impact factor. Investigation considering different type of bridges and tracks including velocity was conducted.

• 생태와환경
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• 제55권4호
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• pp.376-389
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• 2022

화학물질은 현대생활에서 없어서는 안될 매우 중요한 요소이며, 그 종류와 발생량이 꾸준히 증가하는 추세이다. 코로나19 발병 이후 소독제 사용증가로 인해 소독제 함유 화학물질의 사용 및 배출 또한 증가했지만, 환경모니터링이나 생물독성연구 외에 생태계 내 거동에 대한 연구는 부족한 실정이다. 본 연구는 2020, 2021년 금강, 한강, 영산강에서 어류를 대상으로 하는 생태계 먹이망을 조사하고, 어류의 근육에서 소독제 성분인 6종의 benzalkonium chloride (BACs)와 5종의 didecyldimethylammonium chlorides (DDACs)농도를 분석하여 생태계 내 거동을 살펴보았다. ∑BACs와 ∑DDACs는 한강에 서식하는 어류의 체내에서 가장 높은 농도로, 뒤이어 영산강, 금강하구언, 갑천 순서로 검출되었으며 강우 이후 물질의 농도와 검출 빈도가 감소하는 것으로 관찰되었다. BAC는 C12와 C14가, DDAC는 C10과 C14가 가장 빈번하게 검출되었다. BAC와 DDAC가 어류 조직에서 검출된 것으로 보아 물질이 생물과 먹이망 내 축적될 수 있음을 확인하였으나, 체내 축적률을 보여주는 biomagnification factor(BMF)가 1 미만의 값으로, 먹이망 내 전달을 보여주는 trophic magnification slope (TMS)이 -0.236에서 0.001의 값으로, trophic magnification factor(TMF)가 0.85에서 1.01의 값으로 도출되어 먹이망을 통해 물질이 확대되기보다는 희석된다는 것을 알 수 있었다.

• 한국정보통신학회논문지
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• 제13권11호
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• pp.2283-2288
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• 2009

인간의 시각정보처리는 망막에서 입력된 영상을 시각피질에 전달될 때 많은 특성을 가지고 있다. 그 중에서 확대성질과 방향성에 대한 민감도를 분석하여 영상인식에 미치는 영향을 분석하고자 한다. 확대성질은 중심와의 영역이 시각피질에서 확대영역으로 할당되는 사실을 확대배율이라고 부른다. 방향수직반응의 가중치와 수평 및 대각선반응의 가중치를 여러 가지로 변동하여 영상의 인식률을 비교함으로써 수직반응 정도에 매우 민감함을 보이며 차후 인간시각모델 구성에 적용하고자 한다.

• 새물리
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• 제68권12호
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• pp.1378-1383
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• 2018

Multi-wavelength holography has a better axial range than single-wavelength holography, thus allowing unambiguous phase imaging. Noise amplification is the limiting factor in multi-wavelength holography as noise is amplified by a factor equivalent to the magnification of the wavelengths. Here, we propose a new algorithm to remove noise amplification in multi-wavelength holography. The proposed method does not use phase unwrapping and removes $2{\pi}$ ambiguities. Experiments and numerical simulations indicated that the proposed method is fast, has low noise, and is useful for measuring samples with arbitrary step heights.

• 한국소음진동공학회논문집
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• 제20권1호
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• pp.22-28
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• 2010

Approximate analysis for a building installed with a friction damper is performed to get insight of its dynamic behavior. Energy balance equation is used to have a closed analytical form solution of dynamic magnification factor(DMF). It is found out that DMF is dependent on friction force ratio and resonance frequency. Approximation of DMF and equivalent damping ratio of a friction damper is proposed with such assumption that the building with a friction damper shows harmonic steady-state response and narrow banded response behavior near resonance frequency. Linear transfer function from input external force to output building displacement is suggested from the simplified DMF equation. Root mean square of a building displacement is derived under earthquake-like random excitation. Finally, design procedure of a friction damper is proposed by finding friction force corresponding to target control ratio. Numerical analysis is carried out to verify the proposed design procedure.

• 조명전기설비학회논문지
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• 제16권1호
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• pp.92-99
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• 2002

배전변전소에서 과도현상은 주로 스위칭으로 인해 발생한다. 본 논문에서는 스위칭 서지 현상을 분석하고, 과도현상을 저감시키는 방법을 상용화된 EDSA의 EMTAP 프로그램을 이용하였다. 과도현상으로 인한 전압의 크기를 제한하는 방법으로 부하측의 역률개선용 캐패시터 뱅크를 노조파 필터로 변환시켰다. 캐패시터 뱅크에 직렬로 연결된 인덕턴스는 부하측에 적절한 수준의 전압으로 낮출 수가 있었다. 또한 EDSA의 고조파 분석 프로그램으로 시뮬레이션한 결과는 고조파 저감 효과도 검증할 수 있었다.

• Journal of Advanced Marine Engineering and Technology
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• 제32권8호
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• pp.1149-1156
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• 2008

The principle of self clamping friction clutch is presented in this paper and the transmitted torque capacity is also calculated. In order to enlarge the friction force, a part of rotating force of driving side is converted to normal force of friction materials by clamping arm. The increased normal force of friction materials assures the large friction force and the transmitted torque capacity of clutch becomes large. The self clamping friction clutch is adopted in the tube type air pressure clutch and the condition of stability is investigated. It is proven that the inclined angle of clamping arm and the friction factor of friction materials are the essential elements in stability and torque capacity of self clamping friction clutch. The transmitted torque capacity of self clamping friction clutch is compared with air pressure clutch. The normal force of friction lining is magnified by 1/(1-k) and the transmitted torque capacity is also magnified with same proportion comparing with air pressure clutch. The larger the friction factor of friction lining, the larger the magnification factor. The longer the clamping arm, the smaller the magnification factor. It must be also noted that the value of k=${\mu}Y/X$ is the criterion of stability. If the value of k=${\mu}Y/X$ is greater than or equal to 1, the self clamping friction clutch is unstable and it can not be used as clutch.