• Communications for Statistical Applications and Methods
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• 제28권2호
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• pp.205-215
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• 2021

Sufficient dimension reduction is useful dimension reduction tool in regression, and sliced inverse regression (Li, 1991) is one of the most popular sufficient dimension reduction methodologies. In spite of its popularity, it is known to be sensitive to the number of slices. To overcome this shortcoming, the so-called fused sliced inverse regression is proposed by Cook and Zhang (2014). Unfortunately, the two existing methods do not have the direction application to large p-small n regression, in which the dimension reduction is desperately needed. In this paper, we newly propose seeded sliced inverse regression and seeded fused sliced inverse regression to overcome this deficit by adopting iterative projection approach (Cook et al., 2007). Numerical studies are presented to study their asymptotic estimation behaviors, and real data analysis confirms their practical usefulness in high-dimensional data analysis.

• Communications for Statistical Applications and Methods
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• 제25권5호
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• pp.513-521
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• 2018

The goal of sufficient dimension reduction (SDR) is to replace original p-dimensional predictors with a lower-dimensional linearly transformed predictor. The sliced inverse regression (SIR) (Li, Journal of the American Statistical Association, 86, 316-342, 1991) is one of the most popular SDR methods because of its applicability and simple implementation in practice. However, SIR may yield different dimension reduction results for different numbers of slices and despite its popularity, is a clear deficit for SIR. To overcome this, a fused sliced inverse regression was recently proposed. The study shows that the dimension-reduced predictors is robust to the numbers of the slices, but it does not investigate how robust its dimension determination is. This paper suggests a permutation dimension determination for the fused sliced inverse regression that is compared with SIR to investigate the robustness to the numbers of slices in the dimension determination. Numerical studies confirm this and a real data example is presented.

• Communications for Statistical Applications and Methods
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• 제28권3호
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• pp.267-279
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• 2021

A regression with multi-dimensional responses is quite common nowadays in the so-called big data era. In such regression, to relieve the curse of dimension due to high-dimension of responses, the dimension reduction of predictors is essential in analysis. Sufficient dimension reduction provides effective tools for the reduction, but there are few sufficient dimension reduction methodologies for multivariate regression. To fill this gap, we newly propose two fused slice-based inverse regression methods. The proposed approaches are robust to the numbers of clusters or slices and improve the estimation results over existing methods by fusing many kernel matrices. Numerical studies are presented and are compared with existing methods. Real data analysis confirms practical usefulness of the proposed methods.

• Communications for Statistical Applications and Methods
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• 제24권5호
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• pp.533-541
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• 2017

Sufficient dimension reduction (SDR) replaces original p-dimensional predictors to a lower-dimensional linearly transformed predictor. The sliced inverse regression (SIR) has the longest and most popular history of SDR methodologies. The critical weakness of SIR is its known sensitive to the numbers of slices. Recently, a fused sliced inverse regression is developed to overcome this deficit, which combines SIR kernel matrices constructed from various choices of the number of slices. In this paper, the fused sliced inverse regression and SIR are compared to show that the former has a practical advantage in survival regression over the latter. Numerical studies confirm this and real data example is presented.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.546-547
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• 2007

Magnesium is widely used as a lightweight alloy for car engine components and case of cellular phone. Extraction technologies of magnesium are divided to fused salt electrolysis process and thermal reduction process. In this study, electrolysis magnesium is prepared by fused salt electrolysis process with magnesium chloride. We compared two kinds of mixed salt at 7V. As a result, 47% of current efficiency was obtained by electrolyzing KCl/NaCl/$MgCl_2$ mixed salt bath at $760^{\circ}C$, and purity of the prepared magnesium was over 98%. With this study, we can scale up fused salt electrolysis device and accumulate basic data which will be needed for designing an electrolysis cell.

• 자원리싸이클링
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• 제26권3호
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• pp.69-78
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• 2017

최근 국내 자동차부품 및 전자기기 산업에서 마그네슘 금속의 수요가 증가하고 있다. 마그네슘 제련은 크게 용융염전해법과 열환원법 두 가지로 대별할 수 있는데, 본 고에서는 마그네슘 금속 제련에 관하여 원료 광석인 마그네사이트로부터 무수염화마그네슘 제조를 거쳐 용융염전해법에 의한 금속 마그네슘 제조까지 실험실 규모로 전해 마그네슘을 제조한 내용을 요약 보고하였다.

• 한국유기농업학회지
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• 제8권2호
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• pp.89-96
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• 2000

To reduce loss of nitrogen and generation of ammonia gas during composting, poultry manure and sawdust were mixed at the equivalent ratio and calcium chloride, fused superphosphate and vermiculite were added. Ammonia and sulfurous gas during composting, and NH4-N and NO3-N contents of composts were periodically measured. With the treatments of 0.5∼3% calcium chloride and 3% fused superphosphate, ammonia and sulfurous gas during composting significantly decreased, and especially generation of gases sharply reduced and a increase of calcium chlorde. Extractable NH4-N content in composts treasted with calcium chloride and fused superphosphate were high but extractable NO3-N markedly decreased. In conclusion, the results suggest that it is necessary the additon of 1∼3% calcium chloride or 3% fused superphosphate to reduce loss of nirogen and generation of offensive odor during composting of poultry manure mixed with sawdust.

• 응용통계연구
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• 제31권6호
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• pp.835-842
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• 2018

충분차원축소의 대표적 방법론 중 하나인 sliced average variance estimation (SAVE)은 슬라이스라고 불리우는 반응변수의 범주화의 총 수에 민감하다고 알려져 있다. 이러한 점을 극복하기 위한 방법으로 최근에 다양한 수의 슬라이스로부터 얻어진 SAVE의 정보를 결합하는 fused SAVE (FSAVE)가 개발되었다. 본 논문에서는 소위 large p-small n 자료라고 불리우는 자료의 수가 변수의 수보다 적은 자료에서 FASVE가 어떻게 실제적으로 사용될 수 있을지에 대해 실증적 분석을 하고자 한다. 이를 위해 근적외분광분석을 통해 얻어진 비스킷 자료를 이용할 것이고, 이러한 자료분석에서 FASVE에 의한 차원축소에 의해 분석된 결과가 기존의 방법론에 비해 우수함을 보고자 한다.

• 자원리싸이클링
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• 제16권2호
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• pp.3-11
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• 2007

최근 국내에서 자동차 부품산업 및 전자기기 산업에서 마그네슘 금속의 수요가 증가하고 있다. 본 고에서는 마그네슘 금속 제련에 관하여 원료 광석, 세계 생산량과 상용화 조업중인 기술들을 요약 정리하였으며, 국내 마그네슘 관련 시장현황과 기술동향들을 조사하였다. 마그네슘 제련은 크게 용융염 제련법과 열환원법 두가지로 대별할 수 있으며 이들 기술의 일반적인 현황을 살펴보았다. 또한, 국내에서 수행중인 마그네슘의 용융염 제련 연구에 대하여 간략히 기술하고, 용융염 제련시 발생되는 염소나 염화수소의 회수 및 처리 등 재활용 분야와 관련기술을 소개하고자 한다.

• 한국세라믹학회지
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• 제44권6호
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• pp.331-337
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• 2007

High temperature reaction behaviors of various oxide materials (such as bauxite, pyrophyllite, mullite and fused silica powders) used in the refractory materials for tap-hole plugging of blast furnace were investigated with varying temperature in the carbon surrounding. Kinetics of carbothermal reduction of $SiO_2$ for forming SiC with high corrosion resistance were strongly dependent on it's crystalline phase. SiC generation yield increased with increasing catalyst amount in oxide regardless of generated SiO gas amount at temperature of $<1500^{\circ}C$. However, in case of fused silica over $1500^{\circ}C$, SiC generation yield was dominantly influenced by SiO amount without catalyst effect. Bauxite showed the most effective carbothermal reduction reaction, since bauxite have a large amount of catalyst and well-dispersed $SiO_2$ phase in oxide matrix.