• International Journal of Aeronautical and Space Sciences
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• 제9권2호
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• pp.79-86
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• 2008

High performance direct-iterative hybrid linear solver for large scale finite element problem is developed. Direct solution method is robust but difficult to parallelize, whereas iterative solution method is opposite for direct method. Therefore, combining two solution methods is desired to get both high performance parallel efficiency and numerical robustness for large scale structural analysis problems. Hybrid method mentioned in this paper is based on FETI-DP (Finite Element Tearing and Interconnecting-Dual Primal method) which has good parallel scalability and efficiency. It is suitable for fourth and second order finite element elliptic problems including structural analysis problems. We are using the hybrid concept of theses two solution method categories, combining the multifrontal solver into FETI-DP based iterative solver. Hybrid solver is implemented for our general structural analysis code, IPSAP.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2002년도 춘계공동학술대회
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• pp.949-952
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• 2002

A regression model is used in predicting the response variable given predictor variables However, in case of large number of predictor variables, a regression model has some problems such as multicollinearity, interpretation of the functional relationship between the response and predictors and prediction accuracy. A clustering method and stepwise regression could be used to reduce the amount of data by grouping predictors having similar properties and by selecting the subset of predictors. respectively. This paper proposes a prediction method combining clustering method and stepwise regression. The proposed method fits a global model and local models and predicts responses given new observations by using both models. The paper also compares the performance of proposed method with stepwise regression via a real data of ample obtained in a steel process.

• 국제강구조저널
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• 제18권4호
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• pp.1410-1419
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• 2018

Recently, a repair method by bonding patch plates is being applied to corroded steel structures. However, one of the issues of patch plate bonding repair is the brittle debonding of the patch plates. Generally, when the delamination of the patch plates occurs, the composite effect acting between the steel members and patch plates abruptly decreases. Therefore, to prevent the brittle debonding of the patch plates, a repair method combining an adhesive and stud bolts is proposed. Till date, tensile and compressive tests have been performed for the proposed method. In this study, plate bending tests were conducted to verify the effectiveness of this method under bending conditions. Furthermore, two types of epoxy resin-based adhesives were prepared to evaluate the effectiveness of the proposed method with different adhesive properties. The test results show that the proposed method is able to prevent the brittle debonding of the patch plates in the case of both epoxy resins.

• 대한교통학회:학술대회논문집
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• 대한교통학회 1999년도 제36회 학술발표회논문집
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• pp.405-410
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• 1999

• 응용통계연구
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• 제21권1호
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• pp.35-51
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• 2008

제 3상 임상시험에서 치료효과가 여러 반응변수(endpoints)로 측정될 때, 이들 반응 변수가 대둥하게 중요하여 주요 반응변수(primary endpoint)를 선택할 수 없는 상황이 발생할 수 있다. O'Brion (1984)은 이들 반응변수 모두를 종합하여 치료효과에 대한 단축검정(one-tailed testing) 통계량으로서 반응변수가 연속형(continuous) 자료로 측정되었을 때 Ordinary Least Square(OLS)와 Generalized Least Square(GLS) 검정 통계량을 제시하였다. Pocock 등 (1987)은 여러 형태, 즉 연속형, 이산형(binary), 생존(survival) 자료의 반응변수를 함께 분석할 수 있음을 언급하고 있으나 실제로 이와 같이 여러 형태의 반응변수 병합에 대한 문제점을 설명하거나 구체적으로 모의 실험으로서 이러한 경우의 OLS와 GLS통계량의 효율성을 알아보지는 않았다. 본 논문에서는 특히 여러 형태의 반응변수를 종합하여 치료효과에 대한 결론을 내리는데 P값의 병합 통계량을 제안하며, 이때 각 반응변수의 치료효과에 대한 검정 결과인 P값은 서로 상관성이 존재하는 P값이다. OLS 및 GLS 검정 통계량보다 장점을 지닌 P값의 병합방법 중, 방법 F와 G는 제 1종 오류가 유의수준보다 커서 검정의 결론이 잘못 내려질 수 있는 경우가 있고 방법 B는 제 1종의 오류가 잘 통계되고 또한 효율성이 높은 것으로 나타났다.

• 한국콘텐츠학회논문지
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• 제22권6호
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• pp.413-427
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• 2022

본 연구의 목적은 플립드 러닝과 프로젝트 기반 학습을 결합한 메타버스 게임화 교수법으로 대학생들의 과제가치와 학업적 자기효능감을 향상시키고 이를 검증하는 것이다. 본 연구의 대상은 청주의 K대학교에서 상담 심리학을 전공하는 16명의 대학생들이다. 대학생들은 각각 실험집단과 비교집단에 배정되었다. 실험집단에는 플립드 러닝과 프로젝트 기반 학습을 결합한 메타버스 게임화 교수법이 적용되었고 비교집단에는 단순 강의식 교수법이 적용되었다. 본 연구에서의 종속변인은 과제가치와 학업적 자기효능감이었다. 그리고 각 변인들을 사전, 사후에 측정하였다. 연구 결과 사후 검사에서 실험집단의 과제가치와 학업적 자기효능감은 비교집단에 비해 통계적으로 유의미하게 높았다. 본 연구의 결과는 플립드 러닝과 프로젝트 기반 학습을 결합한 메타버스 게임화 교수법이 대학생들의 과제가치 및 학업적 자기효능감의 향상에 효과적임을 시사한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.593-596
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• 1999

In this paper, we propose an image retrieval system using the MBCM(Modified Borda Count method) in CME(Combining Multiple Experts). It combines color-, shape- and texture-based retrieval sub-systems. CME method can complementarily combine results of each retrieval system, which uses different features. There are some problems when the Borda count method in pattern recognition is applied to image retrieval. Thus, we propose a modified Borda count method to solve these problems. In the experiment, our method reduces false positive errors and produces better results than that of each retrieval module that uses only one feature.

• 로봇학회논문지
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• 제8권2호
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• pp.104-115
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• 2013

For natural human-robot interaction, we need to know location and shape of facial feature in real environment. In order to track facial feature robustly, we can use the method combining particle filter and active appearance model. However, processing speed of this method is too slow. In this paper, we propose two ideas to improve efficiency of this method. The first idea is changing the number of particles situationally. And the second idea is switching the prediction model situationally. Experimental results is presented to show that the proposed method is about three times faster than the method combining particle filter and active appearance model, whereas the performance of the proposed method is maintained.

• 대한임베디드공학회논문지
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• 제14권6호
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• pp.321-327
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• 2019

Spectral Beam Combining (SBC) is used for a high-power fiber laser in order to overcome the power limitation of single fiber laser. In SBC, several laser bwams with different wavelengths are combined to obtain a single-aperture beam by diffraction grating. The combining efficiency is dependent on a linewidth, beam quality and specific wavelength of each beam among others. In this paper, we consider the method of a wavelength monitoring and a feedback control of laser diodes used as seeds of laser beams to obtain optimum combining conditions. In order to measure the wavelengths of multi-beam, we use the high resolution camera and diffraction grating with 1,800l/mm. The experiment results show the possibility of feedback control of a current and temperature of multi-seed laser diodes to obtain optimum wavelengths for SBC.

• International Journal of Industrial Entomology and Biomaterials
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• 제13권2호
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• pp.63-72
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• 2006

Parthenogenesis, the development of unfertilized ovum opens new perspectives in silkworm breeding in the development of homozygous breeds. In order to improve induction of artificial parthenogenesis in the excised unfertilized eggs of different breeds of the silkworm, Bombyx mori L., a new method was devised and the results were compared with the routine method. General and specific combining abilities and hybrid vigour of newly developed bivoltine breeds were analyzed utilizing bivoltine breeds viz., $CSR_2,\;CSR_4,\;CSR_{17}\;and\;NB_4D_2$ Estimation of GCA revealed superiority of the breeds, $DNB_1$ for eight characters followed by $DNB_4$ for five characters. Among the testers, $CSR_2$ was found good general combiner for seven characters followed by $CSR_{17}$ for four characters. A great deal of variations was observed among the hybrids studied. Five hybrids namely, $DNB_1{\times}CSR_2,\;DNB_4{\times}CSR_4,\;DNB_4{\times}NB_4D_2,\;DNB_6{\times}CSR_2\;and\;DNB_7{\times}CSR_2$ showed significant SCA effects for 5-6 characters. The hybrid, $DNB_4{\times}CSR_4$ showed its superiority by expressing significant hybrid vigour over BPV for 7 characters. Majority of the hybrids exhibited significant hybrid vigour for survival rate, yield/10,000 larvae by weight, cocoon weight, cocoon shell weight, filament length and denier.