• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.359-364
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• 2002

Statistical energy method is widely used for the prediction of vibrational and acoustical behavior of complex structures, such as ship building and automobile in mid-, high frequency ranges. However. in order to convince this SEA result, it is important to verify estimated SEA parameters, e. g. modal density, energy in each subsystem, damping loss factor, coupling loss factor. with possible other method. For modal density parameter, the experimental estimations via Experimental Modal Analysis are checked with those from finite element method for both beam- plate and plate-plate cans. Loss factors are calculated by Lyon's simple method for the two subsystem. finally. modal experiments are carried out by varying the mass added on the junction of two subsystem for the purpose of investigating the influence on the coupling loss factor's behavior.

• 한국경영과학회지
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• 제35권2호
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• pp.71-88
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• 2010

A density-based outlier detection such as an LOF (Local Outlier Factor) tries to find an outlying observation by using density of its surrounding space. In spite of several advantages of a density-based outlier detection method, the computational complexity of outlier detection has been one of major barriers in its application. In this paper, we present an LOF algorithm that can reduce computation time of a density based outlier detection algorithm. A kd-tree indexing and approximated k-nearest neighbor search algorithm (ANN) are adopted in the proposed method. A set of experiments was conducted to examine performance of the proposed algorithm. The results show that the proposed method can effectively detect local outliers in reduced computation time.

• Journal of Electrical Engineering and information Science
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• 제2권4호
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• pp.72-78
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• 1997

A free space transmission method using standard gain horn antennas in the frequency range from 9.0 to 10.5GHz is applied to determine the dielectric properties of grain such as rough rice ,brown rice and barley. The dielectric constant and loss factor, which depend on the moisture content of the wetted grain are obtained from the measured attenuation and phase shift by vector network analyzer. The moisture content of grain varied from 11 to 25% based on this wetted condition. The measured values of dielectric constants as a function of moisture density are compared with values of those obtained using he predicted model for estimating dielectric constants of grain. The effect of density fluctuation, high is an important parameter governing the dielectric properties of grain, on the dielectric constant and loss factor is presented. A new density-independent model in terms of measured attenuation an moisture density is proposed of reducing the effects of density fluctuation on the moisture content measurement.

• 한국산림과학회지
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• 제100권4호
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• pp.535-539
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• 2011

본 연구는 리기다소나무림을 대상으로 임령을 20년생 이하와 21년생 이상으로 구분하여 줄기밀도와 바이오매스 확장계수의 안정성을 부트스트랩(Bootstrap) 기법으로 평가하고자 하였다. 줄기밀도($g/cm^3$)는 20년생 이하에서 0.460, 21년생 이상에서 0.456으로 나타났으며, 바이오매스 확장계수는 20년생 이하에서 2.013, 21년생 이상에서 1.171로 나타났다. 부트스트랩 추정치를 100번, 500번 반복 시행한 결과, 줄기밀도($g/cm^3$)는 20년생 이하에서 0.462~0.465로 나타났고 21년생 이상에서 0.456~0.457로 나타났다. 바이오매스 확장계수의 추정치는 20년생 이하에서 1.990~2.039로 나타났고 21년생 이상에서는 1.170~1.173으로 나타났다. 실측치와 부트스트랩 추정치의 평균값 차이(Difference)는 5% 내에서 일치하는 것으로 나타났으며, 줄기밀도는 20년생 이하에서 평균의 차이가 0.441~1.049%의 범위로 나타났고 21년생 이상에서는 0.123~0.206%로 나타났다. 바이오매스 확장계수는 20년생 이하에서 평균의 차이가 -1.102~1.340% 사이에서 나타났으며 21년생 이상에서 -0.024~0.215%로 나타났다. 줄기밀도와 바이오매스 확장계수를 시뮬레이션 기법으로 평가한 결과, 줄기밀도는 1.1%, 바이오매스 확장계수는 1.4% 이내로 나타났으며 20년생 이하가 21년생 이상보다 오차가 큰 것으로 나타났다.

• 한국의류산업학회지
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• 제20권4호
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• pp.457-463
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• 2018

This study examined the water absorption and drying properties of the thirteen types of the knitted fabrics for sports wear. These physical properties were analysed with relation to the constituent fiber cross-sectional shape and structure parameters of the knitted fabrics by regression analysis. Absorption and drying properties of the knitted fabric specimens were increased with increasing the porosity of the constituent yarns, which was attributed to the capillary channels in the yarns. The water absorption and drying properties were increased and decreased with increasing tightness factor and stitch density of the knitted fabric. The absorption property of the knitted fabric for perspiration absorption and fast dry sport-wear clothing was mostly influenced mostly by fiber cross-sectional shape and its characteristics, whereas, drying property was dependent on the structural parameters of the knitted fabric such as tightness factor and stitch density. Therefore, superior perspiration absorption and fast drying knitted fabric could be obtained in the fabric structure with optimum tightness factor and stitch density, and constituent yarn structure with non-circular fiber crosssection and high porosity. GATS method and MMT method are used to measure sweating fast drying properties and it is necessary to carry out studies using these measurement methods in order to compare with the results of this study.

• 한국구조물진단유지관리공학회 논문집
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• 제15권2호
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• pp.70-78
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• 2011

본 논문은 변형률 계측데이터를 사용하는 신뢰성 및 정확성을 증진된 BWIM(Bridge Weigh-In-Motion) 알고리즘을 개발하고, 이를 교량에 대한 다양한 실험을 통해 검증하고자 하는 것이다. 본 논문에서는 밀도추정함수와 평균보정계수를 이용한 BWIM 알고리즘을 제시한다. 밀도추정함수는 다축하중을 추정할 때 신뢰할 수 있게 적용할 수 있음을 입증하였으며, 평균보정계수는 이론 계산된 모멘트와 계측된 변형률에서 계산한 모멘트 사이의 전반적인 오차를 최소화하기 위해 적용된다. 개발된 알고리즘은 수치예제, 실내모형실험 그리고 다주형 합성교량에 대한 현장실험을 통해 성공적으로 검증하였다.

• 디지털융복합연구
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• 제11권12호
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• pp.551-556
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• 2013

전완부와 요추부의 골밀도 검사를 통해 얻은 골밀도 값, T-score 와 Z-score 수치간의 상관관계 및 보정함수를 구해 어느 한 부위의 결과로서 다른 부위의 결과를 유추하는데 목적이 있다. 환자 66명은 연령별로 11명씩 20대에서 70대까지 환자들로 구성하였고 측정된 전완부와 요추부의 골밀도와 T-score와 Z-score를 조사하여 세가지 사항들에 대해 각각 상관관계가 있는지 평가하고 그 상관관계를 구하여 보정계수를 찾는다. 골밀도의 상관계수는 R=0.769 이고 보정계수 식은 Y=1.541X + 0.133 이다. T-score의 상관계수는 R=0.768 이고 보정계수식은 Y=0.715X - 0.4 이다. Z-score의 상관계수는 R=0.635 보정계수식은 Y=0.751X - 0.162 이다. 상관관계와 보정계수식를 통해 어느 한 부위의 결과로서 다른 부위의 결과를 유추할 수 있는 임상적 유용성이 있을 것으로 사료된다.

• ETRI Journal
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• 제27권3호
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• pp.319-325
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• 2005

In this paper the effect of temperature on the electrical properties of organic semiconductor disperse orange dye 25 (OD) have been examined. Thin films of OD have been deposited on $In_{2}O_{3}$ substrates using a centrifugal machine. DC current-voltage (I-V) characteristics of the fabricated devices $(Al/OD/In_{2}O_{3)$ have been evaluated at varying temperatures ranging from 40 to $60^{\circ}C$. A rectification behavior in these devices has been observed such that the rectifying ratio increases as a function of temperature. I-V characteristics observed in $Al/OD/In_{2}O_{3)$ devices have been classified as low temperature $({\leq} 50^{\circ}C)$ and high temperature characteristics (approximately $60^{\circ}C$). Low temperature characteristics have been explained on the basis of the charge transport mechanism associated with free carriers available in OD, whereas high temperature characteristics have been explained on the basis of the trapped space-charge-limited current. Different electrical parameters such as traps factor, free carrier density, trapped carrier density, trap density of states, and effective mobility have been determined from the observed temperature dependent I-V characteristics. It has been shown that the traps factor, effective mobility, and free carrier density increase with increasing values of temperature, whilst no significant change has been observed in the trap density of states.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 춘계학술대회
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• pp.275-278
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• 2017

차량의 교류발전기는 성능 및 효율에 따라 자동차의 연비와 배기가스에 많은 영향을 준다. 효율을 개선시키고 연비를 향상시키려는 노력은 자동차업체및 업체를 중심으로 계속되고 있다. 본논문은 A교류 발전기의 설계절차를 정리하고 같은 크기의 교류발전기에서 출력을 최적화하는 인자를 발굴하여 실차의 조건에서 충방전 Simulation을 통해 Energy Balance를 검증하였다.

• Journal of Biosystems Engineering
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• 제24권2호
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• pp.123-134
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• 1999

The electrical properties such as dielectric constant, dielectric loss factor and AC conductivity of grain were presented to measure the moisture content of grain using RF impedance. At frequency ranging from 1 to 10MHz and room temperature, $20^{\circ}C$, vector network analyzer(HP4195) and coaxial type sample holder were used to analyze the electrical properties of paddy(11∼24%w.b.), brown rice(11∼18%w.b.), barley(11∼21%w.b.) and wheat(11∼23%w.b.) depending on the moisture content, frequency and bulk density. The dielectric constant and AC conductivity of grain samples increased with moisture content and bulk density. The dielectric constants decreased with frequency and could be expressed as function of the moisture density(decimal moisture $content{\times}bulk$ density).