• Nuclear Engineering and Technology
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• 제48권5호
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• pp.1120-1125
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• 2016

The neutron decay constant, ${\alpha}$, and effective delayed neutron fraction, ${\beta}_{eff}$, are important parameters for the control of the dynamic behavior of nuclear reactors. For the heavy water zero power reactor (HWZPR), this document describes the measurements of the neutron decay constant by noise analysis methods, including variance to mean (VTM) ratio and endogenous pulse source (EPS) methods. The measured ${\alpha}$ is successively used to determine the experimental value of the effective delayed neutron fraction as well. According to the experimental results, ${\beta}_{eff}$ of the HWZPR reactor under study is equal to 7.84e-3. This value is finally used to validate the calculation of the effective delayed neutron fraction by the Monte Carlo methods that are discussed in the document. Using the Monte Carlo N-Particle (MCNP)-4C code, a ${\beta}_{eff}$ value of 7.58e-3 was obtained for the reactor under study. Thus, the relative difference between the ${\beta}_{eff}$ values determined experimentally and by Monte Carlo methods was estimated to be < 4%.

• Geomechanics and Engineering
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• 제31권5호
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• pp.453-460
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• 2022

It is essential for geotechnical engineers to conduct studies and make predictions about the stability of slopes, since collapse of a slope may result in catastrophic events. The Gaussian process regression (GPR) approach was carried out for the purpose of predicting the factor of safety (FOS) of the slopes in the study that was presented here. The model makes use of a total of 327 slope cases from Iran, each of which has a unique combination of geometric and shear strength parameters that were analyzed by PLAXIS software in order to determine their FOS. The K-fold (K = 5) technique of cross-validation (CV) was used in order to conduct an analysis of the accuracy of the models' predictions. In conclusion, the GPR model showed excellent ability in the prediction of FOS of slope stability, with an R² value of 0.8355, RMSE value of 0.1372, and MAPE value of 6.6389%, respectively. According to the results of the sensitivity analysis, the characteristics (friction angle) and (unit weight) are, in descending order, the most effective, the next most effective, and the least effective parameters for determining slope stability.

• 한국도서관정보학회지
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• 제42권2호
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• pp.323-341
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• 2011

본 연구에서는 국내 공공도서관의 이용가치에 영향을 미치는 요인을 분석하였다. 이용자의 진술을 통해 가치가 도출되는 CVM을 이용한 측정에서 응답자의 특성, 도서관의 특성과 같은 다양한 변인들이 미치는 영향들을 파악하고자 하였다. 이를 위해 국내외 공공도서관의 가치측정 연구에서 밝혀진 영향변인들을 분석하였고 여기서 나타난 영향요인들의 특성을 파악하였다. 도서관의 가치를 나타내는 지불의사액에 많은 영향을 미치는 요인은 이용자의 성별, 수입, 연령, 수입과 같은 인구통계학적 특성과 이용빈도, 방문소요시간과 같은 이용형태이다. 만족도와 인식 영역에서는 정보, 시설, 프로그램의 세가지 서비스 유형에 따라 사서의 만족도, 주민교류의 장, 경제적 도움 정도, 문화예술지원자에 대한 인식이 영향을 미치고 있었다. 이 연구는 국내 모든 유형의 공공도서관을 대상으로 측정한 가치에 미치는 영향력을 포괄적으로 분석함으로써 지역과 규모별로 이용자가 평가하는 가치의 속성에 대한 정보를 제공하였다. 이러한 정보는 향후 도서관의 가치를 높이기 위한 전략적인 정책수립에 도움이 될 것으로 기대된다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 추계 학술논문 발표대회
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• pp.129-132
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• 2012

Value Engineering(VE) process is going to make a series of improvements for the effective construction project management or optimal proposal to improve quality, performance improvement, cost reduction and customer satisfaction. For making the quality model based on better than the architecture that is required in the VE, such a project promoting creative plan, functionality and constructability reflecting the materials and improved construction methods and building life cycle for reviewing the smooth progress of the construction projects may be necessary for management techniques. This study is to establish a management plan in the educational facilities construction process through education institution's recent orders completed by VE case study.

• 한국수산과학회지
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• 제3권3호
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• pp.172-176
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• 1970

This research dealt with the nutrient value of the seaweed, Sargessum horneri (Turner) C. Ag. which showed the highest nutrient value in the previous exporiment (Park 1968). Its objective was to find the most effective mixing ratio of ordinary chicken feed used for pullet. In order to investigate the most effective mixing ratio, seven kinds of sample feed with vary-ing amounts of the seaweed as shown in table 2 were prepared and were fed to seven groups of chickens, each group consisting of twenty, four week old, pullets. In addition, the effect of sodium glutaminate mixed in the feed was also investigated, and the following result was obtained. The average increase in body weight of each group during the experiment period was determined. The group fed with the feed containing $10\%$ powdered Sargassum horneri (Turner) C. Ag. showed the highest body weight increase. In this experiment the body weight increase was accelerated by mixing $0.5\%$ sodium glutaminate In the above feed.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2001
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• pp.331-338
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• 2001

Seismic performances of the base isolated model of Five Story Stone Pagoda were studied through shaking table tests. Friction pendulum system (FPS), Pure-friction system with laminated rubber bearing (LRB) and Ball with rubber bearing were selected fur the comparison of performances. Performances of specially designed isolation systems were tested dynamically using shaking table. The test results of isolated model are compared with those of fixed base model. Compared with fixed base model, the isolated model showed that it could withstand much higer intensity of earthquake motion. The Effective Peak Ground Acceleration (EPGA) value of isolated model when the top component tipped over was above twice of that value in case of fixed base model. According to the additional test results, the lower value of coefficient of friction than that of common frictional base isolation systems is more effective to protect the piled multi-block system of Pagoda against moderate intesity of ground motion.

• 대한전자공학회논문지SD
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• 제41권11호
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• pp.15-20
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• 2004

본 논문에서는 초고주파나 밀리미터파 대역에서 코프래너 도파로 구조로부터 S-파라메타를 이용하여 유효유전상수를 도출하는 간단한 방법을 제시하였다. 이 방법은 특성임피던스 Z/sub o/와 전송선 길이 ℓ로 주어진 전송선이 주파수가 변화함에 따라 나타나는 S/sub 11/ 값으로부터 βℓ =nπ 에서 극한적으로 바뀌는 것을 이용하여 유효유전상수 ε/sub eff/를 도출하는 기법이다. ε/sub r/=3.38의 Rogers 4003/sup TM/ 기판 위에서 실험적으로 얻어진 유효유전상수 값은 2.042로 나타났으며, 기존의 공식으로부터 얻어진 ε/sub eff/ 값은 -3.4%에서 8% 범위의 오차를 보여 주었다. 코프래너 도파로 구조의 유효유전상수 값이 간단한 측정 방법으로 뿐만 아니라 제작된 회로 구조 위에서 직접 측정될 수 있어, 복잡한 회로 구조를 지닌 다른 유전체 재질의 기판 위에서도 측정이 보다 정확하고 간단하게 이루어 질 수 있음을 보여 주었다.

• Journal of Biosystems Engineering
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• 제42권4호
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• pp.258-264
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• 2017

Purpose: This study determines the spray characteristics and effective spray width of a tractor-mounted commercial boom sprayer through experiments. Methods: Performance tests were conducted to investigate the spray characteristics of the nozzles on a commercial boom sprayer. The flow rate and spray width of a single nozzle were measured at three levels of spray pressure (0.5, 0.7, and 1.0 MPa) and spray height (15, 30, and 45 cm), respectively. The average value of three repetition tests was used as the representative value. A coefficient of variation (CV) was used as an index of spray uniformity, and the width that guarantees CV values of approximately 15% was determined as the effective spray width. The spray characteristics of the overall boom sprayer were derived analytically by superimposing the spray characteristics of a single nozzle. Results: The test results for a single nozzle showed that the spray width tended to increase as the spray height and spray pressure increased. The effective spray width for a single nozzle was the largest at a spray pressure of 1.0 MPa and spray height of 45 cm, which resulted in a coverage of 84 cm of width. The effective spray width for the entire boom sprayer was also the largest at the spray pressure of 1.0 MPa and spray height of 45 cm, with a magnitude of 424.5 cm. The chemical spraying work in an actual field was simulated by applying a spray width of 400 cm. As a result of the operation for three swaths, the CV value was less than 10% for 1,200 cm of the overall spray width, which meant that uniform application was achieved. Conclusions: It was reasonable to set the effective spray width of the boom sprayer used in this study to 400 cm.

• 한국방사선학회논문지
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• 제13권4호
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• pp.517-522
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• 2019

이 연구의 목적은 AAPM CT 성능 팬텀 안에 있는 CT 수 교정 삽입부의 CT 슬라이스 영상들을 사용하여 CT X-선 빔들의 유효에너지를 결정하는데 있다. AAPM CT 성능 팬텀의 CT 수 교정 삽입부는 80, 100, 120 kVp X-선 빔에 대하여 CT 스캐너로 5번 스캔되었다. 각 핀의 CT 수는 각각의 CT 슬라이스 영상에 대하여 측정되었다. 상관계수들은 각 핀에서 측정된 CT 수의 평균값과 미국표준기술연구소의 자료로부터 계산된 다른 광자에너지 하에 선감약계수를 선형정합하여 얻었다. 얻어진 상관계수의 최대값에 대응하는 광자에너지는 유효에너지로 결정하였다. 결과로서, 유효에너지는 80, 100, 120 kVp X-선 빔들에 대하여 각각 56, 62, 66~67 keV이다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.259-262
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• 2008

This paper introduces a simplified method to consider forming effects in a car crash analysis. Representative value was used to consider forming effects simply. Four representative values, which are the mean value of thicknesses and effective plastic strains at nodes, the median of thicknesses and effective plastic strains at nodes, were evaluated. A crash analysis of a front side member shows that analysis results from the suggested methods are similar to those from the conventional method to consider forming effects. Use of the mean effective plastic strain shows the best results. A car crash analysis for a ULSAB/AVC model under the condition of US SINCAP were carried out to demonstrate the validity of the suggested method. Analysis results show that the error of suggested method is less than 1.5%.