• 한국터널지하공간학회 논문집
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• 제4권3호
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• pp.217-227
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• 2002

${\bigcirc}{\bigcirc}$ 터널 구간의 지하수유동분석을 위해 지구통계학적 기법을 적용하였다. 이 지역의 표고와 관정 및 터널시추공에서의 지하수위의 선형회귀분석결과 상관성이 매우 큰 것으로 나타났다. 보통크리깅 및 공크리깅을 이용하여 작성된 지하수위 등고선도는 표고등고선도를 기준으로 비교해보면 공크리깅에 의한 것이 정밀성이 더 큰 것으로 나타났다. 보통크리깅과 공크리깅에 의해 작성된 지하수위 등고선도에서는 지하수 유동상태를 검토해 보면, 북서쪽의 산악지형에서 계곡쪽으로, 봉우리 일대에서 외곽쪽으로 각각 유동하는 것으로 나타났다. 본 연구를 통해 터널굴착 예정지역의 정확한 분석이나 관측자료의 평가없이 사용하던 지하수위 분포를 정량적으로 설계에 반영할 수 있었으며, 공간상에 분포하는 자료측정의 제한성과 경제적인 이유로 충분한 자료를 확보할 수 없는 현실에 비추어 볼 때 지구통계학은 미지의 구간에 대해 보다 정량적인 자료를 제공할 수 있음을 보여주었다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2005년도 추계학술대회 논문집
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• pp.289-295
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• 2005

LMTT(Linear Motor-based Transfer Technology)는 항만 자동화를 위한 수평 이송 시스템이며, 셔틀카(shuttle car)와 격자구조의 레일에 부착된 스테이터 모듈(stator module)로 구성된 PMLSM(Permanent Magnetic Linear Synchronous Motor)에 의해 구동된다. 본 논문에서는 LMTT시스템에서 컨테이너 운반을 담당하는 셔틀카(shuttle car)를 구성하는 부품인 이동체(mover)의 경량화를 위하여 직교배열표 및 크리깅 방법을 이용하여 최적설계를 수행한다. 설계변수로는 가로빔, 세로빔, 휠빔의 두께를 제한조건 함수로는 안전율이 고려된 응력을 넘지 않도록 설정하였다. 목적함수로는 중량을 설정하였다. 본 연구에서 제시된 방법으로 구한 최적해는 크리깅 내삽법(Kriging interpolation)으로 알려진 DACE(Design and Analysis of Computer Experiments) 모델을 엑셀(Excel)로 수식화하고 구했으며, GENESIS를 이용하여 민감도기반 최적설계로 구해진 최적해와 비교 및 검토하였다.

• 한국환경과학회지
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• 제28권4호
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• pp.423-433
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• 2019

This study was carried out to identify the problems of the underground watersheds on Jeju Island, and to establish the hydraulic groundwater basin to be used as basis for the analysis of the groundwater model. In order to evaluate the adequacy of the groundwater basin on Jeju Island, a correlation analysis between elevation and groundwater level was conducted using data from 125 observation wells. The analysis, conducted with an elevation step of 100 m, exhibited values of R2 in the range 0.1653-0.8011. No clear correlation was observed between elevation and groundwater level. In particular, the eastern and western areas showed an inverse proportionality between elevation and groundwater level. The Kriging technique was used to analyze the underground water level data and to define the equipotential lines for all areas of Jeju Island. Eight groundwater watersheds were delineated by considering the direction of groundwater flow, the positions of the observation wells, and the long and short axes of the watersheds.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.864-869
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• 2004

It is net easy to predict the shrinkage rate of a plastic injection mold in its design process. The shrinkage rate should be considered as one of the important performances to produce the reliable products. The shrinkage rate can be determined by suing the CAE tools in the design produces. However, since the analysis can take minutes to hours, the high computational costs of performing the analysis limit their use in design optimization. In this study, the surrogate models based on the DACE is used in lien of the original models, facilitating design optimization.

• 한국항공운항학회지
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• 제18권4호
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• pp.67-72
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• 2010

In this study, performance analysis and design optimization is carried out for a multi-rate spring brake system, which is used in a cable ride to stop the arriving passengers in safe and comfortable manner. Mathematical model for the spring is developed toward the objective of minimizing the impact at the arrival while satisfying the constraint of limited distance at the stop. Matlab code is utilized to examine parameters affecting the performance of the brake system. The results are validated by a commercial software RecurDyn. Kriging meta model is used to reduce the computational cost of the analysis. Optimization is conducted by RecurDyn, from which the design parameters are determined that minimizes the impact at the stop.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제37회 추계학술대회논문집
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• pp.523-526
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• 2011

본 연구는 재료물성치의 불확실성을 고려한 구조신뢰성 해석 기법에 대한 내용이다. 설계변수의 확률분포 및 상태한계방정식을 구하고 이에 대한 확률밀도함수와 누적분포함수 계산 시 근사화 기법인 크리깅을 적용하여 구조신뢰성에 대한 계산 및 해석시간을 단축하고자 하였다. 이에 대한 예제로 알루미늄을 소재로 하는 로켓모터케이스의 재료물성치의 분포를 고려한 구조신뢰성 해석을 수행하고 그 결과를 몬테카를로 시뮬레이션과 비교함으로써 제안된 기법에 대한 정확성과 효율성을 판단하고자 한다.

• 한국항해항만학회지
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• 제34권7호
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• pp.553-558
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• 2010

This study presents the optimization design process of a segment ball valve that involves the reduction of the flow resistance coefficient and the satisfaction of the strength requirement. Numerical analysis of fluid flow and structural analysis have been performed to predict the flow resistance coefficient and the maximum stress of a segment ball valve. In this study, a segment ball valve incorporating the advantages of a ball valve and a butterfly valve has been devised. In general, ball valves are installed in a pipe system where tight shut off is required. Butterfly valves having smaller end-to-end dimension than ball valve can be installed in narrow spaces in a pipe system. The metamodels for the shape design of a segment ball valve are built by the response surface method and the Kriging interpolation model.

• Journal of Electrical Engineering and Technology
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• 제10권2호
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• pp.641-646
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• 2015

In this paper, a zinc electrowinning cell is fully optimized to achieve a uniform current distribution at electrode surfaces. To effectively deal with an electromagnetically coupled problem with multi-dimensional design variables, a sampling-based sensitivity approach is combined with a highly tuned multiphysics simulation model. The model involves the interrelation between electrochemical reactions and electromagnetic phenomena so as to predict accurate current distributions in the electrowinning cell. In the sampling-based sensitivity approach, Kriging-based surrogate models are generated in a local window, and accordingly their sensitivity values are extracted. Such unique design strategy facilitates optimizing very complicated multiphysics and multi-dimensional design problems. Finally, ten design variables deciding the electrolytic cell structure are optimized, and then the uniformity of current distribution in the optimized cell is examined through the comparison with existing cell designs.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.225-228
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• 2007

This paper presents a geostatistical methodology to model local uncertainty in spatial estimation of sediment grain size with high-resolution remote sensing imagery. Within a multi-Gaussian framework, the IKONOS imagery is used as local means both to estimate the grain size values and to model local uncertainty at unsample locations. A conditional cumulative distribution function (ccdf) at any locations is defined by mean and variance values which can be estimated by multi-Gaussian kriging with local means. Two ccdf statistics including condition variance and interquartile range are used here as measures of local uncertainty and are compared through a cross validation analysis. In addition to local uncertainty measures, the probabilities of not exceeding or exceeding any grain size value at any locations are retrieved and mapped from the local ccdf models. A case study of Baramarae beach, Korea is carried out to illustrate the potential of geostatistical uncertainty modeling.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.909-910
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• 2007

The volatile organic compounds exposure is governed by the source distance and dispersion of the pollutant into air and groundwater. The purpose of this study was to validate suggested models for the prediction of concentration distributions. The study design was organized into different methods to simulate industry site. The distribution models generally showed a fair agreement with measured data. For graphical representation of concentration of volatile hydrocarbon, it has to obtain a continuous representation of the contamination of the site. Therefore, the used interpolative methods examined for this project are the IDW(inverse Distance Weighting) and kriging method. In the results, in summary, all two different methods can be used to quantify exposures at a particular source area, and thus provide, a solid foundation for making risk-based decisions. All the calculations can be performed using Excel's built-in functions, and the capabilities of geospatial analysis allow the results to be displayed visually. However, anyone who uses these methods should understand all of the assumptions and limitation.