• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.201-204
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• 1999

Polarization mode dispersion (PMD) restrict the bend-width of single mode optical filer, and it is important parameter in the optical fiber having long-length. Although fiber has perfect circular symmetry, fiber bending, twisting and laws governing manufacture cause additional Polarization mode dispersion. The effect of polarization mode dispersion in general single mode fiber of long length is discussed in this paper. Measurement of PMD with random mode coupling were conducted in two kind of fibers using different laws governing manufacture and interferometric method.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.342-343
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• 2012

We studied the Drain-Induced-Barrier-Lowering (DIBL) effect by different drain engineering. One other drain engineering is symmetric source-drain n-channel MOSFETs (SSD NMOSs), the other drain engineering is asymmetric source-drain n-channel MOSFETs (ASD NMOSs). Devices were fabricated using state of art 40 nm dynamic-random-access-memory (DRAM) technology. These devices have different modes which are deep drain junction mode in SSD NMOSs and shallow drain junction mode in ASD NMOSs. The shallow drain junction mode means that drain is only Lightly-Doped-Drain (LDD). The deep drain junction mode means that drain have same process with source. The threshold voltage gap between low drain voltage ($V_D$=0.05V) and high drain voltage ($V_D$=3V) is 0.088V in shallow drain junction mode and 0.615V in deep drain junction mode at $0.16{\mu}m$ of gate length. The DIBL coefficients are 26.5 mV/V in shallow drain junction mode and 205.7 mV/V in deep drain junction mode. These experimental results present that DIBL effect is higher in deep drain junction mode than shallow drain junction mode. These results are caused that ASD NMOSs have low drain doping level and low lateral electric field.

• Steel and Composite Structures
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• 제2권5호
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• pp.331-354
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• 2002

Tethers of Tension Leg Platform (TLP) are a series structural system where fatigue is the principal mode of failure. The present study is devoted to the fatigue and fatigue fracture reliability study of these tethers. For this purpose, two limit state functions have been derived. These limit state functions are based on S-N curve and fracture mechanics approaches. A detailed methodology for the reliability analysis has then been presented. A sensitivity analysis has been carried out to study the influence of various random variables on tether reliability. The design point, important for probabilistic design, is located on the failure surface. Effect of wind, water depth, service life and number of welded joints are investigated. The effect of uncertainties in various random variables on tether fatigue reliability is highlighted.

• Journal of Power Electronics
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• 제15권5호
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• pp.1358-1366
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• 2015

This study focuses on an advanced second-order sliding mode control strategy for a variable speed wind turbine based on a permanent magnet synchronous generator to maximize wind power extraction while simultaneously reducing the mechanical stress effect. The control design based on a modified version of the super-twisting algorithm with variable gains can be applied to the cascaded system scheme comprising the current control loop and speed control loop. The proposed control inheriting the well-known robustness of the sliding technique successfully deals with the problems of essential nonlinearity of wind turbine systems, the effects of disturbance regarding variation on the parameters, and the random nature of wind speed. In addition, the advantages of the adaptive gains and the smoothness of the control action strongly reduce the chatter signals of wind turbine systems. Finally, with comparison with the traditional super-twisting algorithm, the performance of the system is verified through simulation results under wind speed turbulence and parameter variations.

• 한국결정학회지
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• 제13권2호
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• pp.69-72
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• 2002

본 연구에서는 적층판 자유단 근처에서의 층간응력 문제를 해석하였다. 탄소섬유 복합적층판 [+40/-40］s과 탄소 부직포가 삽입된 적층판 ［+40//-40］s 이 인장하중을 받고 있는 경우에 대하여 해석한다. 부호 “//”는 층간에 부직포가 위치함을 의미한다. 부직포를 삽입함으로서 모우드 Ⅱ의 층간파괴인성치는 크게 증가하지만 모우드 I의 값은 크게 변하지 않음이 보고되어 있다./sup 3)/ 복합재료 구조물에 있어서 모우드 Ⅲ 층간파괴인성치가 중요하지만 그 값을 실험적으로 평가하기는 어렵다. 따라서, 본 연구에서는 부직포 효과 특히, 적층판 자유단 근처에서의 모우드 Ⅲ층간파괴 특성을 이해하기 위하여 유한요소 해석을 통해 전단응력을 분석하고자 한다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.699-710
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• 2020

Pitting corrosion commonly shaped in hull structure due to marine corrosive environment seriously causes the deterioration of structural performance. This paper deals with the ultimate strength behaviors of stiffened ship panels damaged by the pits subjected to uniaxial compression. A series of no-linear finite element analyses are carried out for three stiffened panels using ABAQUS software. Influences of the investigated typical parameters of pit degree (DOP), depth, location and distribution on the ultimate strength strength are discussed in detail. It is found that the ultimate strength is significantly reduced with increasing the DOP and pit depth and severely affected by the distribution. In addition, the pits including their distributions on the web have a slight effect on the ultimate strength. Compared with regular distribution, random one on the panel result in a change of collapse mode. Finally, an empirical formula as a function of corrosion volume loss is proposed for predicting the ultimate strength of stiffened panel.

• 한국해안·해양공학회논문집
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• 제31권6호
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• pp.434-449
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• 2019

파형의 왜도, 저류 외에도 구속 모드의 외중력파, 경계층 streaming이 반영된 개선된 횡단표사 모듈이 제시되었으며, 개선된 모듈에서는 단위 관측기간 내에서 출현하기 마련인 개별 파랑도 고려된다. 이어 불규칙한 개별 파랑이 표사이송에 미치는 영향을 확인하기 위해 단조해안에서의 비선형 천수과정과 해변변형을 수치모의 하였다. 모의결과 최근 적용범위가 쇄파역으로 확대된 주파수 영역 Boussinesq Eq.은 쇄파역에서 흔히 관측되는 치근 모양의 파형, 구속 모드의 외중력파, 경계층 streaming의 모의가 가능한 것으로 판단된다. 또한 연 최대 고파랑이라는 해양환경을 등가 비선형 규칙파[Cnoidal wave]로 해석하는 경우 최대 횡단표사 이송률은 불규칙 파랑에서 관측되는 이송률의 세 배에 달할 정도로 지나치게 과다하게 모의되었으며, 이는 외빈과 원빈의 과다한 침식으로 이어졌다. 또한 연안 표사 이송과 관련된 free parameter K를 최적화하기 위해 맹방해빈의 2017.4.26부터 2018.4.20까지의 해안선 변화를 수치모의 하였으며, 최적화 과정에는 실측된 해안선 위치를 활용하였다. 모의 결과 맹방 표사계의 경우 최적화된 K는 0.17로 보이며, 이 경우 10월 말에 연이어 내습한 최대 고파랑에 의해 침식된 해안이 동절기와 춘절기의 너울에 의해 점진적으로 복원되는 대순환 과정을 거쳐 해안선이 맹방해안 남단과 북단에서는 18 m, 맹방 해안 중앙부에서는 2.4 m 내외로 전진하는 관측결과에 상당히 근접한 수치모의가 가능한 것을 확인하였다.

• 대한전자공학회논문지SD
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• 제37권8호
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• pp.48-56
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• 2000

회절격자의 인접한 반주기 길이 사이에 음의 상관관계가 있는 회절격자 반주기의 랜덤 변이가 QWS-DFB 레이저의 특성에 미치는 영향을 유효 굴절률 전달 매트릭스 방법을 이용하여 해석하였다. 상관계수가 0에서 -1로 가까이 감에 따라 랜덤 변이에 의한 회절격자 주기의 오차가 감소하면서 단일모드 안정성과 파장 정확도의 저하가 덜 심각해진다. 이는 랜덤 변이의 크기가 같다면 상관관계가 없는 전자빔 lithography 법으로 회절격자를 만들기보다는 optical lithography 법으로 만드는 것이 회절격자 주기 랜덤 변이의 영향을 줄이는 데에 유리함을 의미한다. 그리고 전자빔 lithography를 이용하여 DFB 레이저를 만들 때에 랜덤 변이의 영향을 줄이려면 분해능을 높이거나, 인접 반주기 길이의 랜덤 변이에 음의 상관관계를 주어야 한다.

• 반도체디스플레이기술학회지
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• 제21권3호
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• pp.39-44
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• 2022

The light extraction technology for improving the light efficiency of OLEDs is the core technology for extracting the light inside the OLEDs to the outside. This study demonstrates a simple method to generate random nanostructures (RNSs) containing high refractive index nanoparticles to improve light extraction and viewing angle characteristics. A simple dry low-temperature process makes the nanostructured scattering layer on the polymer resin widely used in the industry. The scattering layer has the shape of randomly distributed nanorods. To control optical properties, we focused on changing the shape and density of RNSs and adjusting the concentration of high refractive index nanoparticles. As a result, the film of the present invention exhibits a perpendicular transmittance of 85% at a wavelength of 550 nm. This film was used as a scattering layer to reduce substrate mode loss and improve EL efficiency in OLEDs.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2011년도 제43차 동계학술발표논문집 19권1호
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• pp.233-236
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• 2011

This paper proposes to use gesture recognition technology to develop 3D game for prevention of dementia. In the game, the user can choose camera mode or mouse mode to play game. In the game design, We focused on the characteristics of dementia, Developed four types of games, Including Memory training game, Math game, Logical training game and 3D visual sense training game. Each type of game is composed by a number of small games. Common feature of all the game is random, This ensures that when user play games, Basically the game will not have the same situation. For the older elderly, If can take 10 minutes a day to play the game and has always insisted on playing, For dementia preventive have a positive effect.