• 한국농공학회지
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• 제33권2호
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• pp.120-129
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• 1991

This study refers to temporal variation of physical properties of tilled soil under natural rainfalls. Field measurements of porosity, average hydraulic conductivity and average capillary pressure head on a tilled soil were conducted by soil sampler and air-entry permeameter respectively at regular intervals after tillage. Temporal variation of these physical properties were analysed by cumulative rainfall energy since tillage. Field experiment was conducted on a sandy loam soil at Suwon durging April~July in 1989. The followings are a summary of this study results ; 1. Average porosity just after tillage was 0.548cm$^3$/cm$^3$. As cumulative rainfall energy were increased in 0.1070, 0.1755, 0.3849 J/cm$^2$, average porosity were decreased in 0.506, 0.4]95, 0.468m$^3$/cm$^3$ respectively. 2. Average hydraulic conductivity just after tillage was 45.42cm/hr. As cumulative rainfall energy were increased in 0.1755, 0.2466, 0.2978, 0.3849J/cm$^2$ average hydraulic conductivity were decreased in 15.34, 13.47, 9.58, 8.65cm/hr respectively. 3. As average porosity were decreased in 0.548, 0.506, 0.495, 0.468cm$^3$/cm$^3$ average capillary pressure head were increased in 6.1, 6.7, 6.9, 7.4cm respectively. 4. It was found that temporal variation of porosity, average hydraulic conductivity on a tilled soil might be expressed as a function of cumulative rainfall energy and average capillary pressure head might be expressed as a function of porosity. 5. The results of this study may be helpful to predict infiltration into a tilled soil more accurately by considering Temporal variation of physical properties of soil.

• Journal of the Korean Wood Science and Technology
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• 제47권3호
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• pp.290-298
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• 2019

The sound absorption coefficient and transmission loss of several types of rice hull mats with varying apparent densities and thicknesses are estimated in this paper using the transfer function and matrix methods, respectively, to evaluate the possibility of using rice hull as an acoustic construction material. The mean sound absorption rates of 10-cm-thick rice hull mats with target densities of $0.10g/cm^3$, $0.12g/cm^3$, and $0.14g/cm^3$ were 0.91, 0.92, and 0.95, respectively, while those of the 1-cm-thick plywood attached to the back of the rice hulls were 0.90, 0.92, and 0.92, respectively. The means of the sound transmission loss of the 10 cm-thick rice hull mats with the target densities of $0.10g/cm^3$, $0.12g/cm^3$, and $0.14g/cm^3$ were 7.66 dB, 10.49 dB, and 14.14 dB, respectively, while those of the 1 cm-thick plywood attached to the back of the rice hulls were 33.34 dB, 36.72 dB, and 38.95 dB, respectively. In conclusion, a rice hull mat could be used as acoustic construction materials because of its high sound absorption coefficient and sound transmission loss.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 추계학술대회 논문집
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• pp.340-341
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• 2010

Noise reduction is an important factor to design low noise sensor array. In this paper three layers of the de-coupler in the conformal sensor array were used to investigate noise reduction. Conformal sensor array is positioned in the layers and the distance from the layer is 0.25cm~1.5cm. Transfer function in the frequency density function is investigated according to the three different positions. When increasing the embedded distance the flow noise decreased in the region of the kx>10.

• Archives of Reconstructive Microsurgery
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• 제14권1호
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• pp.14-17
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• 2005

Purpose: Authors have performed free tissue transplantation in the upper and lower extremities with sensory flaps and evaluated the sensory function recovery. Materials and methods: Between 1992 through 2004, sensory free flap articles published in the journal of the Korean microsurgical society, were reviewed and recovery of sensory function was assessed by static two-point discrimination test. Results: Static two point discrimination test showed average 6.7 mm in the thumb, average 12 mm in the hand and 7 cm of the dorsalis pedis flap, 20.5 mm of the lateral arm flap and over 8 cm of the forearm flap in the foot. Conclusion: Sensory flaps provide the protective and useful coverage in the upper and lower extremities and have benefit for activities for daily life in free tissue transferred patients.

• 한국건설관리학회논문집
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• 제14권1호
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• pp.133-143
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• 2013

BIM과 건설사업관리(Construction Management; 이하 CM)는 건설정보를 통합 관리하고 신뢰성 있는 의사결정을 지원하는 수단이라는 점에서 그 성격이 유사하기 때문에 BIM은 CM에 효율적으로 활용할 수 있으나, CM 분야에서 BIM 도입은 미흡한 실정이다. 이 연구의 목적은 시공단계의 CM 업무에 BIM을 효과적으로 활용할 수 있도록 업무절차 모델 및 가이드를 제시하는 것이다. 문헌조사를 통해 BIM 기능을 BIM 전환설계, 모델 검토, 데이터 추출, 자동 견적, 4D 시뮬레이션, 도면 생성, 엔지니어링 분야 연계분석 등으로 정의하고, CM 업무와 프로세스를 분석하여 BIM의 적용이 가능한 CM 업무를 도출하였다. BIM 기능과 CM 업무 간 연관성 분석을 통해 기존의 업무절차를 BIM 기능과 연계하여 재구성하고, 사업 참여자별 역할을 재정립하여 BIM기반 CM 업무절차 모델을 개발하였다. 개발된 모델의 효용성을 향상시키고자 면담조사와 사례조사를 통해 사업 참여자들의 BIM 업무를 기술한 가이드를 작성하였다. 또한 BIM기반 CM 업무절차 모델의 활용성을 검증하기 위한 선행연구의 BIM 프로세스와 비교 분석하고 전문가를 대상으로 설문조사를 수행하였다. 이 연구는 CM 분야에서 BIM의 활용성을 높이는데 기여할 수 있다. 향후에는 사례적용을 통해 실무적 관점에서 모델을 평가할 필요가 있으며, BIM 도입으로 인한 CM 업무의 확대를 고려하여 지속적으로 BIM기반 CM 업무절차 모델을 업데이트할 필요가 있다.

• 센서학회지
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• 제3권3호
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• pp.3-8
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• 1994

정온발열 특성을 갖는 PTC 써어미스터를 사용하여 유속센서를 제조하였다. $(Ba_{0.7}Sr_{0.3})TiO_{3}$ 분말을 사용하여 PTC 써어미스터를 제조한 후, 유속에 따른 저항률의 변화를 조사하였다. 유속이 0 cm/s에서 5 cm/s로 변할 경우 저항률은 4.45 $k{\Omega}{\cdot}cm$에서 3.95 $k{\Omega}{\cdot}cm$로 변하였다. 유속이 1 cm/s와 5 cm/s일 경우 PTC 써어미스터의 감도는 -204 (${\Omega}{\cdot}cm$)/(cm/s)와 -24 (${\Omega}{\cdot}cm$)/(cm/s)로 나타났다.

• The Journal of Korean Physical Therapy
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• 제26권3호
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• pp.169-174
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• 2014

Purpose: This study demonstrated a postural alignment exercise as conservative management strategy for a woman with excessive thoracic kyphosis presenting decreased chest function, and reports its results. Methods: A 21-year-old woman with thoracic kyphosis presenting limited chest function. The exercise program underwent for 30 min in the intervention phase, which consisted of exercises to improve the strength of back extensor and to stretch anterior chest region. Outcome measures comprised the severity of thoracic kyphosis and chest function (vital capacity [VC], forced expiratory volume in a second [FEV1], and chest expansion length). Results: The thoracic kyphotic angle decreased by 23.6% ($9.38^{\circ}$) and 25.4% ($10.58^{\circ}$) in the intervention and follow-up phases respectively. Also, chest function was improved in the intervention (VC: 3.7% [$0.10{\ell}$], FEV1: 17.1% [$0.39{\ell}$], and chest expansion length: 17.1% [0.96 cm]), and the improvement was maintained during the follow-up phase (VC: 4.8% [$0.13{\ell}$], FEV1: 17.1% [$0.39{\ell}$], and chest expansion length: 64.3% [1.81 cm]). Conclusion: These findings suggest that the postural alignment exercise was favorable for improving chest function of a woman with thoracic kyphosis.

• International Journal of Contents
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• 제13권4호
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• pp.23-28
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• 2017

Of the total economic loss caused by disasters, 40% are due to floods and floods have a severe impact on human health and life. So, it is important to monitor the water level of a river and to issue a flood warning during unfavorable circumstances. In this paper, we propose a modified error function to improve a hydrological modeling using a multi-layer perceptron (MLP) neural network. When MLP's are trained to minimize the conventional mean-squared error function, the prediction performance is poor because MLP's are highly tunned to training data. Our goal is achieved by preventing overspecialization to training data, which is the main reason for performance degradation for rare or test data. Based on the modified error function, an MLP is trained to predict the water level with rainfall data at upper reaches. Through simulations to predict the water level of Nakdong River near a UNESCO World Heritage Site "Hahoe Village," we verified that the prediction performance of MLP with the modified error function is superior to that with the conventional mean-squared error function, especially maximum error of 40.85cm vs. 55.51cm.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.289-294
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• 2007

국내 CM방식은 1996년 12월 건설산업기본법에 의해 제도화된 후 10년이 지난 현재, 건설 경기가 침체되었음에도 불구하고 공공 공사에 CM 방식의 도입으로 본격화되었으며 CM 제도의 운영 방향이 발표된 2001년 대비 2005년 말 CM발주는 계약건수 6.7배, 계약금액 9.2배가 증가하여 CM시장은 급격히 확대 발전하고 있다. 그러나 CM사업데 대한 신뢰부족 및 CM방식의 필요성을 인식하지 못하고 있으며, CM의 성공적인 정착에 중요한 역할을 하는 발주자에 대한 연구가 충분히 이루어지지 못한 것으로 판단된다. 이러한 점을 감안하여 CM 도입과 활용에 있어서 중요한 역할을 하는 발주자의 업무 수준 조사 및 분석을 통해 발주자가 필요로 하는 업무 분야에 CM방식을 제안함으로써 건설사업관리를 활성화시키고자 하였다. 발주자의 역량 수준 조사를 위하여 기존 문헌을 고찰한 결과 발주자 업무 기능을 10가지로 분류하였고 이를 토대로 설문조사를 실시하였다.

• Current Optics and Photonics
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• 제6권3호
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• pp.244-251
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• 2022

We introduce a spectral reconstruction method to enhance the spectral resolution in a static modulated Fourier-transform spectrometer. The optical-path difference and the interferogram in the focal plane, as well as the relationship of the interferogram and the spectrum, are discussed. Additionally, for better spectral reconstruction, applications of phase-error correction and apodization are considered. As a result, the transfer function of the spectrometer is calculated, and then the spectrum is reconstructed based on the relationship between the transfer function and the interferogram. The spectrometer comprises a modified Sagnac interferometer. The spectral reconstruction is conducted with a source with central wave number of 6,451 cm^-1 and spectral width of 337 cm^-1. In a conventional Fourier-transform method the best spectral resolution is 27 cm^-1, but by means of the spectral reconstruction method the spectral resolution improved to 8.7 cm^-1, without changing the interferometric structure. Compared to a conventional Fourier-transform method, the spectral width in the reconstructed spectrum is narrower by 20 cm^-1, and closer to the reference spectrum. The proposed method allows high performance for static modulated Fourier-transform spectrometers.