• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.658-660
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• 1999

본 논문에서는 축구로봇 시스템에서 상위 레벨 제어기에 해당하는 행동선택기를 다층신경회로망을 이용하여 설계한다. 축구로봇 시스템에서 로봇의 속도가 빠른 상태에서 제어가 가능하도록 로봇의 행동레벨을 설정하고 주어진 동적 상황에 대해 여러 가지 상황변수를 정의하여, 각 상황에 가장 효율적이며 최적의 행동을 선택하도록 한다. 각 로봇이 목표점으로 이동할 때 어떠한 행동을 선택하여 어떻게 움직이느냐에 따라 로봇은 같은 위치에서 목표점을 이동하더라도 이동경로가 달라진다. 따라서, 로봇축구 경기 상황을 나타내는 상황 변수들을 입력으로 하는 다층신경회로망을 사용하여 출력으로 행동을 판단하여 실행하는 알고리즘을 제안하고 그를 위한 하드웨어와 시뮬레이터 도구를 제작한다. 역전파 알고리즘을 통해 신경망을 학습하고 학습된 데이터를 실험에 적용한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.1001-1006
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• 2004

본 연구에서는 요소를 사용하지 않고 절점들만을 이용하여 해석이 가능한 수치기법인 무요소절점법(element-free Galerkin method)의 개념을 선형파의 회절 및 방사문제에 적용하는 방법에 대해 연구하였다. 파동장에 놓인 부유식 구조물에 의한 연직 2차원 경계치 문제를 해석 대상으로 하였고, 파랑과 구조물의 상호작용을 해석함에 있어 구조물에 작용하는 동유체력과 이로 인한 구조물의 동적응답을 계산하기 위해서 무요소절점법을 이용하였다. 무요소절점법의 수식화과정을 체계적으로 정리하였으며, 무요소절점법의 타당성 및 적용성을 입증하기 위해서 직사자형 부유체에 내한 수치해석을 실시하여 타 논문의 결과와 비교하였다. 또한 해의 정확도에 직접적으로 영향을 미치는 절점간격과 파수와의 관계에 대한 기준 설정을 위한 수치실험도 수행하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.242-245
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• 2012

본 보고서는 지상파방송 디지털 전환 과정에서 아직 전송방식조차 선정하지 못하고 있는 라디오의 디지털화 추진과 관련하여 AM 라디오의 DRM 전송방식에 의한 실험방송 조기 추진의 필요성과 의미를 설명하고, FM의 디지털화 역시 DRM+ 전송방식 중심으로 TV채널 5번과 6번 LOW-VHF 밴드 주파수 대역에서의 OUT-OF-BAND 방법으로 검토해 봄으로써 기존 FM송신기 및 안테나와 콤바인이 쉽고 우수한 신호 전달력을 가진 LOW-VHF대역 주파수를 효과적으로 활용할 수 있으며 각 사업자별로 출력지정과 권역설정이 자유로워 디지털시대에 맞는 새로운 서비스 환경 구축과 AM/FM대역 동일방식 디지털 라디오 보급을 할 수 있는 특징으로 인해 라디오의 디지털화 추진에 유리한 방안임을 확인해 보고자 한다.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.05a
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• pp.278-285
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• 2002

본 논문에서는 인지적 긍정/부정 선택 과제의 수행 시 뇌파를 이용하여 피험자의 반응시간 RT를 감지하는 방법에 관하여 기술한다. 실험 Task에서 피험자는 시각적 자극에 대한 반응, 문제의 해석, 손 움직임의 조절, 손동작 등과 같은 작업을 수행한다. 이와 같은 상황에서의 피험자의 정신상태의 변화를 모델링하고, 선택시간 ST를 감지하여 피험자의 반응시간 RT를 예측한다. ST를 감지하기 위하여 측정한 뇌파로부터 $\alpha$, $\beta$, ${\gamma}$파를 분리하고, 4쌍의 전극들로부터 3가지의 특징들을 추출한다. 추출한 특징들을 분석하여 각 피험자별로 나타나는 상세 규칙과 공통적인 특성인 일반 규칙들을 설정하고 이들을 적용한다. 4명의 피험자를 대상으로 평균 81%의 ST 감지 성공률을 보이고, ST 감지 이후 약 0.73초에서 RT가 나타나는 것을 보인다. 본 논문에서 제안한 방법을 기존의 인지적인 정신상태 판별을 위한 방법들이나 왼손/오른손 동작구분 방법들과 결합하여 사용할 경우 BCI를 위한 기반 기술로 활용될 것으로 기대한다.

• Geophysics and Geophysical Exploration
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• v.14 no.2
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• pp.146-151
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• 2011

A method to evaluate and to reduce the source- and receiver- consistent noise in a cross-well travel time data was proposed. These systematic noises, which can cause some serious effects on the result of a travel time tomography, can be considered as the source and receiver statics. The method evaluates the statics through a curve-fitting of the first arrival travel times in the common source and common receiver gathers. Feasibility study was conducted on a synthetic data which simulates the cross-well travel time tomography to detect a small scale tunnel in a uniform background medium. First arrival travel times at a given source and receiver points are computed by a raytracing method, and the source consistent- and receiver consistent noises are added to the record. In case of the added noise with rms amounting to 25% of the maximum expected anomalous travel time delays, it is confirmed that the method successfully extracted the noise at the 7th step of iteration.

• The Journal of the Acoustical Society of Korea
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• v.16 no.5
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• pp.76-82
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• 1997

The paper describes simulations and experimental results using a measuring system which utilizes the acoustic holographic method in order to exactly estimate an absolute position of a sound source. The measuring surface is installed to satisfy with a far field to the sound source and is composed of linear arrayed seven microphones. A measurement is simultaneously recorded by a reference microphone setting up a neighbour sound source and the linear arrayed seven microphones which are moved to the same interval. An absolute position of sound source is estimated by the cross-spectrum method to the received sounds between a reference and the measuring microphones. Phase differences of each microphone and time delays during scanning are compensated to the reference microphone and the measuring time of the first column. An optimal interval for each microphone in the measuring surface is decided by a numerical simulation. A source signal makes use of a sinusoid, and S/N ratio is 30dB in the experiment. The optimal microphone's interval in the simulation and the experiment is decided in order to satisfy with the Nyquist space sampling condition related to the wave length of 2kHz sinusoid. Mainlobe width of a estimated 3D hologram in the case of 2kHz source signal is decreased to 87% and 30% in comparison to 500Hz and 1kHz, and then a valid of simulation results is confirmed. Therefore, we verified a utilization of the study for a sound source estimation using 3ㅇ acoustic holographic method.

• The Journal of Engineering Geology
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• v.14 no.4 s.41
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• pp.401-416
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• 2004

We have collected shale specimens from the Pungam Basin in Kangwon province and investigated change of physical properties by freezing and thawing in water as well as in acidic fluid. The temperature range was $-20{\pm}2^{\circ}C\~15{\pm}2^{\circ}C$. Specimens were frozen for 12 hours and thawed in water for 8 hours. Then, they were saturated in the vacuum chamber for 4 hours to make specimens fully saturated. This procedure was 1 cycle. We have measured absorption, ultrasonic velocity, shore hardness, slake durability and uniaxial compressive strength at every 5th cycles. The physical properties increased or decreased as freezing and thawing cycles increased. Uniaxial compressive strength decreased by 0.40MPa per cycle in water and by 0.48MPa in acidic fluid. Elastic constant also decreased by 0.21GPa per cycle in water and by 0.30GPa in acidic fluid. Absorption increased by $0.29\%$ and $0.37\%$ per cycle in water and acidic fluid, respectively. These results indicate that decrease in uniaxial compressive strength, elastic constant and absorption by freezing and thawing in acidic fluid is more rapid than in water. Ultrasonic velocities, shore hardness and slake durability show no differences in water and acidic fluid. When we compared our results with the temperatures in the Hongchon during the winter season, $6\~12$ cycles may be equivalent to 1 year.

• Korean journal of food and cookery science
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• v.13 no.4
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• pp.472-477
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• 1997

Iron was bound to neutral detergent fiber (NDF) obtained from 15 kinds of vegetables commonly consumed in Korea. Iron binding capacity of NDF ranged from 37.83% to 85.51%, and it increased as the pH increased and reached to the maximum at pH 7 in all vegetables. The amount of Fe bound to NDF increased as the Fe concentration increased.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.17 no.2
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• pp.95-106
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• 2006

Iron was bound by neutral detergent fiber(NDF) obtained from 15 kinds of vegetables being consumed commonly in Korea. Binding capacity of Fe of NDF ranged from 37.83% to 85.51%. Fe binding capacity of NDF increased as pH increased and reached to a maximum at pH 7 in all vegetables. The amount of Fe bound to NDF increased as Fe concentration increased.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.2
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• pp.133-144
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• 2006

In order to catch out such Bond Strength, the preceding researchers had ever examined the Bond Strength of FRP Plate through their experimentations by setting up of various fluent. However, since the experiment for research on such Bond Strength takes much of expenditure for equipment structure and time-consuming, also difficult to carry out, it is conducting limitedly. This Study purposes to develop the most suitable Artificial Neural Network Model by application of various Neural Network Model and Algorithm to the adhering experiment data of the preceding researchers. Output Layer of Artificial Neural Network Model, and Input Layer of Bond Strength were performed the learning by selection as the variable of the thickness, width, adhered length, the modulus of elasticity, tensile strength, and the compressive strength of concrete, tensile strength, width, respectively. The developed Artificial Neural Network Model has applied Back-Propagation, and its error was learnt to be converged within the range of 0.001. Besides, the process for generalization has dissolved the problem of Over-Fitting in the way of more generalized method by introduction of Bayesian Technique. The verification on the developed Model was executed by comparison with the resulted value of Bond Strength made by the other preceding researchers which was never been utilized to the learning as yet.