• 인터넷정보학회논문지
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• 제10권6호
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• pp.19-26
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• 2009

이 논문에서는 오차 확률 밀도와 델타 함수 사이의 유클리드 거리를 최소화하는 기준을 소개하고 이 기준에 근거한 새로운 CMA 형태의 블라인드 등화 알고리듬을 제안하고 있다. 제안한 기준에 나타나는 오차 항 대신에 constant modulus error를 대치하여 블라인드 알고리듬을 완성하였고 이 알고리듬은 블라인드 등화 환경에서 탁월한 수렴성능과 정상상태의 자승평균오차 성능 특성을 보였으며, 오차 신호 값이 0 값에 보다 집중된 밀도함수 형태를 나타냈다. 시뮬레이션 결과로부터, 이 제안된 방식은 멀티 포인트 통신에서 블라인드 등화를 위한 신뢰성 있는 알고리듬으로 사용될 수 있음을 보이고 있다.

• 한국농공학회지
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• 제45권7호
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• pp.57-69
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• 2003

To evaluate nutrient dynamics with different fertilization in paddy field and develop water quality model, mass balance analysis was performed during growing season of 2001-2002 in field experimental plots irrigated with groundwater. As a result of water balance analysis, most of outflow was surface drainage as about half of total outflow and about 500mm was lost by evapotranspiration. The water budget was well balanced. The runoff from paddy field was influenced by rainfall and forced drain. Especially runoff during early cultural periods more depends on the forced drain. As a result of mass balance analysis, most of nutrient was input by fertilization and lost by plant uptake. Significant amount of nitrogen were supplied by precipitation and input from upper paddy field, comprising 12%∼28% of total inflow. Nutrient loading by surface drainage was occurred showing about 15%∼29% for T-N and 6%∼13% for T-P. The response of rice yield with different fertilization was not significant in this study. Water quality model for paddy field developed using Dirac delta function and continuous source was calibrated and validated to surface water quality monitoring data. It demonstrates good agreement between observed and simulated. The nutrient concentration of surface water at paddy field was significantly influenced by fertilization. During early cultural periods when significant amount of fertilizer was applied, surface drainage from paddy field can cause serious water quality problem. Therefore, reducing surface drainage during fertilization period can reduce nutrient loading from paddy fields. Shallow irrigation, raising the weir height in diked rice fields, and minimizing forced surface drainage are suggested to reduce surface drainage outflow.

• Wind and Structures
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• 제23권6호
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• pp.615-639
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• 2016

Although the underlying mechanism of rain-wind induced vibrations (RWIVs) of stay cables has not been fully understood, some countermeasures have been successfully applied to mitigating this kind of vibration. Among these, installing dampers near the bridge deck was widely adopted, and several field observations have shown its effectiveness. In this study, the effectiveness of dampers to RWIVs of stay cables is numerically investigated comprehensively by means of finite difference method (FDM). Based on the free vibration analysis of a taut string, it is found that the 3-points triangle scheme, which can be easily implemented in FDM, can offer an excellent approximation of the concentrated damping coefficient (expressed as a Dirac delta function) at the location where the damper is installed. Then, free vibration analysis of a 3-D continuous stay cable attached with two dampers is carried out to study the relationship of modal damping ratio and damping coefficient of the dampers. The effects of orientation of the dampers and cable sag on the modal damping ratio are investigated in detail. Finally, the RWIV response of a 3-D continuous stay cable attached with two dampers is examined. The results indicate that 0.5% of damping ratio is sufficient to reduce the RWIV vibration of the Cable A20 on the No.2 Nanjing Bridge over Yangtze River.

• Earthquakes and Structures
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• 제9권6호
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• pp.1133-1152
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• 2015

A frequency-domain method is developed for evaluating the earthquake input energy to two building structures connected by viscous dampers. It is shown that the earthquake input energies to respective building structures and viscous connecting dampers can be defined as works done by the boundary forces between the subsystems on their corresponding displacements. It is demonstrated that the proposed energy transfer function is very useful for clear understanding of dependence of energy consumption ratios in respective buildings and connecting viscous dampers on their properties. It can be shown that the area of the energy transfer function for the total system is constant regardless of natural period and damping ratio because the constant Fourier amplitude of the input acceleration, relating directly the area of the energy transfer function to the input energy, indicates the Dirac delta function and only an initial velocity (kinetic energy) is given in this case. Owing to the constant area property of the energy transfer functions, the total input energy to the overall system including both buildings and connecting viscous dampers is approximately constant regardless of the quantity of connecting viscous dampers. This property leads to an advantageous feature that, if the energy consumption in the connecting viscous dampers increases, the input energies to the buildings can be reduced drastically. For the worst case analysis, critical excitation problems with respect to the impulse interval for double impulse (simplification of pulse-type impulsive ground motion) and multiple impulses (simplification of long-duration ground motion) are considered and their solutions are provided.

• 한국전자통신학회논문지
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• 제12권6호
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• pp.1027-1034
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• 2017

본 논문은 양자게이트의 모든 제어 동작점에서 양자들의 확률진폭, 확률, 평균 기댓값 및 정상상태 단위행렬의 행렬요소 등을 수학적 투사로 측정할 수 있는 새로운 함수 임베딩 방법을 제안하였다. 본 논문의 함수 임베딩 방법은 디랙 기호와 크로네커델타 기호를 사용해 각 제어 동작점에 대한 확률진폭의 직교 정규화조건을 2진 스칼라 연산자에 임베딩 한 것이다. 이와 같은 함수 임베딩 방법은 양자게이트 함수를 단일양자들의 텐서 곱으로 표현하는 유니터리 변환에서 유니터리 게이트의 산술 멱함수 제어에 매우 효과적 수단임을 밝혔다. Ternary 2-qutrit cNOT 게이트에 본 논문이 제안한 함수 임베딩 방법을 적용했을 때의 진화연산과 투사측정 결과를 제시하고, 기존의 방법들과 비교 검토하였다.

• 인터넷정보학회논문지
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• 제19권3호
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• pp.49-56
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• 2018

오차 신호에 대해 가우시안 커널이 가지는 과도신호 차단효과를 기반으로 설계된 오차분포와 델타함수 사이의 유클리드 거리(ED)가 충격성 잡음하에서 효과적인 성능준거로 사용되어왔다. ED의 최소화 과정에서 필요한 기울기는 두 가지 성분, 즉, 오차 쌍의 커널함수에 대한 성분$A_k$와 오차 샘플 자체의 커널함수에 대한 성분 $B_k$를 가진다. 이 논문에서는 성분 $A_k$가 오차 샘플들을 서로 결집시키는 역할과 관련되어 있으며, 성분 $B_k$는 오차샘플들의 결집위치가 영(0)이 되는 문제와 관련되어 있다고 분석되었다. 이 분석에 기반하여, 이 논문에서는 오차 샘플간 간격을 좁히는 역할을 강화하고자 $A_k$를 커널 통과된 오차쌍의 전력으로 정규화하고, 오차 샘플들을 0점에 당기는 역할을 강화하고자 $B_k$를 커널 통과된 오차샘플 자체의 전력으로 정규화하는 방안을 제안하였다. 충격성 잡음과 다중경로 페이딩 채널 환경하에서 시뮬레이션을 시행하여, 정상상태의 MSE 가지는 흔들림 정도와 최소 MSE 값을 비교 분석하였다. 그 결과, 제안된 방식이 가지는 효용성과 두 성분의 역할이 분석과 일치함이 규명되었다.