• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.1
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• pp.1-8
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• 2019

An experimental study is performed to observe the characteristics of the thrust vectoring control (TVC) of the supersonic jet using proportional control valves. It is observed that three different TVC characteristics exist as the nozzle pressure ratio varies. Strong hysteresis phenomena are also observed during the valve control for a certain range of the nozzle pressure ratio. It is also noticed that the secondary chamber pressure is one of the influencing parameters for the TVC. Therefore, a control algorithm utilizing the secondary chamber pressure coefficient as a predictor is applied to achieve the stable TVC avoiding the hysteresis. Consequently, the stable TVC with the maximum deflection angle of about 20-degree has been realized using the proportional control valves.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.3
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• pp.51-55
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• 2023

Measurement of the ferroelectric polarization hysteresis curve is an important means of overall evaluation and interpretation of the ferroelectric structure and dielectric properties. If a resistive component is included in the ferroelectric sample, an error is included in the measured value of the spontaneous polarization. When configuring the electrical circuit to measure the polarization, by properly utilizing the external resistance corresponding to the resistive component included in the sample, the error due to the resistive loss of the sample was excluded and the size of the ferroelectric polarization induced inside could be accurately measured. It is expected that the displacement and dielectric characteristics of ions inside the ferroelectric can be more accurately evaluated through the evaluation of such an accurate polarization hysteresis curve.

• Journal of the Korea Computer Industry Society
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• v.5 no.9
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• pp.1031-1042
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• 2004

A renewable energy resource data has the characteristic that its measurement value changes every moment. So the amount of primitive data which is produced by the change of time arevast. Therefore researches are needed for the construction of history database which can save and manage vast amount of history information of renewable energy resource data systematically, the estimation system of renewable energy resources. In this paper, to solve these problems, the estimation method of renewable energy resources is suggested. The method makes it possible to estimate momently changing data of the past systematically.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.696-699
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• 2003

In this study, we suggested the model to precisely evaluate the ferroelectric hysteresis loop, using the modified Sawyer-Tower circuit and the ferroelectric capacitor with a MDFM(Metal-Dielectric-ferroelectric-Metal) structure. The mathematical expression of dipole polarization is applied to the numerical integration algorithm, and the fatigue property can be considered including the dielectric layer between ferroelectrics and bottom electrode. The validity of our model is proved comparing the estimated value of our model and the measured results of PLT(10) thin film.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.05a
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• pp.367-370
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• 2019

본 논문은 구매이력 데이터에서 상품간의 분류 체계를 고려하여 시퀀스 간의 유사도를 계산하는 새로운 방법을 제안한다. 시퀀스란 두 항목간의 순서가 존재하는 데이터를 의미한다. 항목 간의 선후관계가 중요한 시퀀스 데이터에서는 두 시퀀스 간의 유사도를 정확히 정의하는 것이 중요하다. 본 논문에서는 대표적인 시퀀스 유사도 측정 알고리즘인 편집 거리 알고리즘을 활용하여 구매이력 데이터에서 시퀀스 간의 유사도를 정의한다. 상품은 상품의 특성에 따라 항목 분류 체계에서 여러 범주로 분류된다. 이 경우 기존의 편집 거리 알고리즘에서 문자의 일치유무에 따라 단순히 0 또는 1을 부여하는 것은 부정확하다. 따라서 본 논문은 편집 거리 알고리즘의 수정 연산 중 대체 연산 비용 계산 시 항목 분류 트리를 사용하여 연산 비용이 0 에서 1 사이의 값을 가지도록 세분화하였다. 실험 결과 제안 방법은 대체 연산 비용 계산 시 두 문자가 다르면 단순히 1 을 부여하는 기존의 편집 거리 알고리즘에 비해 시퀀스 간의 유사도를 더 정확하게 계산함을 확인하였다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.3 s.55
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• pp.217-224
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• 2009

Many engineering researches are performed to ensuring structural safety from earthquake. In this study, the damping capacity of LRB(lead rubber bearing) with high lead-plug area ratio was examined by hysteresis loop from experiments. The displacement controlled tests were performed for 12 specimens designed in 2 types by lead-plug area ratio as main parameter. Each coupled specimens were tested by 3 times sinusoidal loads with different loading velocities. From the experimental results, LRB with high lead-plug area ratio has sufficient damping ratio for reducing horizontal seismic load to structures.

• Proceedings of the Materials Research Society of Korea Conference
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• 1999.11a
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• pp.27-27
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• 1999

• 지반과기술
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• v.3 no.1
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• pp.43-51
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• 2006

• Water for future
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• v.52 no.5
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• pp.36-41
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• 2019

• Journal of Navigation and Port Research
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• v.37 no.2
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• pp.143-148
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• 2013

The aim of this study is to investigate the characteristics on the profile of local ice load acting on side shell of port side in bow part due to broken ice during icebreaking of ships in ice covered waters. The first Korean icebreaking research vessel 'ARAON' had a sea ice field trial in the Arctic Sea during early August, 2010, and the signals due to local ice impact measured from several strain gauges installed at bow part were gathered. It is known that these data with structural response characteristics due to local ice impact have some different characteristics with a typical hydraulic impact pressure - time history. In this study, the time history on the measured signals was analyzed and the characteristic values were presented using non-dimensional parameters.