• Bulletin of the Korean Chemical Society
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• 제13권3호
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• pp.285-289
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• 1992

Enantiomeric separation of underivatized amino acids using N-alkyl-L-proline (octyl, dodecyl or hexadecyl) coated HPLC has been accomplished. The anchoring N-alkyl groups of L-proline provides a permanent adsorption of there solving chiral agent on the hydrophobic interface layer of a reversed phase. The factors controlling retention and enantioselectivity such as the Cu(II) concentration, pH of the eluent, the type and concentration of organic modifier in the hydroorganic eluent, and extent of coating were examined. The elution orders between D- and L-amino acids were consistent, L-forms eluting first, except histidine and asparagine. The extremely high enantioselectivity $(\alpha$ upto 13 for proline) is observed. The retention mechanism for the chiral separation can be illustrated by a complexation and hydrophobic interaction.

• ETRI Journal
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• 제44권3호
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• pp.504-511
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• 2022

Monte Carlo simulations show that, as temperature increases, the average kinetic energy of channel electrons in a GaN transistor first decreases and then increases. According to the calculations, the relative energy change reaches 40%. This change leads to a reduced barrier height due to quantum coupling among the three-dimensional motions of channel electrons. Thus, an analysis and physical model of the gate leakage current that includes drift velocity is proposed. Numerical calculations show that the negative and positive temperature dependence of gate leakage currents decreases across the barrier as the field increases. They also demonstrate that source-drain voltage can have an effect of 1 to 2 orders of magnitude on the gate leakage current. The proposed model agrees well with the experimental results.

• Journal of the Korean Statistical Society
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• 제16권1호
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• pp.1-9
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• 1987

Recently a new form of the extended Yule-Walker equations for a mixed autoregressive moving-average process of orders p and q has been proposed. It can be used to obtain p+q+1 parameter values from the first p+q+1 autocovariance terms. The autoregressive part of the equations is linear and can be easily solved. In contrast the moving-average part is composed of nonlinear simultaneous equations. Thus some iterative algorithms are necessary to solve them. The iterative algorithm presented by Choi(1986) is very simple but its convergence has not been proved yet. In this paper a Newton-Raphson solution for the moving-average parameters is presented and its convergence is shown. Also numerical example illustrate the performance of the algorithm.

• 환경생물
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• 제39권4호
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• pp.573-580
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• 2021

Unarmored and thin-walled dinoflagellates were collected from brackish and coastal waters of Korea from August 2019 to August 2021. A total of 10 species belonging to orders Sussiales and Gymnodiniales were isolated and established as clonal cultures. Of them, five species (Biecheleria brevisulcata, Lepidodinium chlorophorum, Karlodinium decipiens, Kirithra asteri, and Wangodinium sinense) are newly recorded in Korea and examined using a light microscope (LM) and a scanning electron microscope (SEM). Their molecular phylogeny was inferred from LSU rDNA sequences. Here, we present taxonomic information, morphological features, and molecular phylogenetic positions of these unrecorded dinoflagellate species.

• 대한수학회보
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• 제60권3호
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• pp.829-844
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• 2023

In this paper, we present a new construction for self-dual codes that uses the concept of double bordered construction, group rings, and reverse circulant matrices. Using groups of orders 2, 3, 4, and 5, and by applying the construction over the binary field and the ring F₂ + uF₂, we obtain extremal binary self-dual codes of various lengths: 12, 16, 20, 24, 32, 40, and 48. In particular, we show the significance of this new construction by constructing the unique Extended Binary Golay Code [24, 12, 8] and the unique Extended Quadratic Residue [48, 24, 12] Type II linear block code. Moreover, we strengthen the existing relationship between units and non-units with the self-dual codes presented in [10] by limiting the conditions given in the corollary. Additionally, we establish a relationship between idempotent and self-dual codes, which is done for the first time in the literature.

• 한국광학회지
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• 제16권1호
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• pp.34-42
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• 2005

본 논문은 3군 구성의 줌 광학계에 대해 렌즈모듈의 개념을 이용하여 1차량 및 3차 수차를 고려한 최적의 초기설계와 이로부터 실제 줌 광학계를 설계하는 방법을 제안 하였다. 각각의 렌즈모듈에 적절히 1차량과 3차 수차량을 설정함으로써 줌비 2배(f = 4.3∼8.6 mm)를 갖고, 시스템에서 요구하는 구속조건을 만족시키는 초기설계 줌 광학계를 얻었다. 각 군의 역할에 따라 적절히 선정된 각각의 렌즈군의 초점거리 및 1차량이 렌즈모듈의 값과 같도록 독립적으로 설계한 후, 군사이의 공기간격을 조정하므로써 줌궤적을 일치시켰다. 이러한 과정을 통해 설계된 줌 광학계는 렌즈모듈로 구성된 원래의 초기 설계된 줌 광학계와 동일한 1차 특성을 갖는다. 결과적으로 잔여수차 보정을 통해 후군초점조절방식을 이용하는 컴팩트 디지털 카메라 및 모바일 폰용 줌 렌즈로서 유용한 줌 광학계를 얻을 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제29권5호
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• pp.607-614
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• 2016

The objectives of the study were to estimate genetic parameters for milk production traits of Holstein cattle using random regression models (RRMs), and to compare the goodness of fit of various RRMs with homogeneous and heterogeneous residual variances. A total of 126,980 test-day milk production records of the first parity Holstein cows between 2007 and 2014 from the Dairy Cattle Improvement Center of National Agricultural Cooperative Federation in South Korea were used. These records included milk yield (MILK), fat yield (FAT), protein yield (PROT), and solids-not-fat yield (SNF). The statistical models included random effects of genetic and permanent environments using Legendre polynomials (LP) of the third to fifth order (L3-L5), fixed effects of herd-test day, year-season at calving, and a fixed regression for the test-day record (third to fifth order). The residual variances in the models were either homogeneous (HOM) or heterogeneous (15 classes, HET15; 60 classes, HET60). A total of nine models (3 orders of $polynomials{\times}3$ types of residual variance) including L3-HOM, L3-HET15, L3-HET60, L4-HOM, L4-HET15, L4-HET60, L5-HOM, L5-HET15, and L5-HET60 were compared using Akaike information criteria (AIC) and/or Schwarz Bayesian information criteria (BIC) statistics to identify the model(s) of best fit for their respective traits. The lowest BIC value was observed for the models L5-HET15 (MILK; PROT; SNF) and L4-HET15 (FAT), which fit the best. In general, the BIC values of HET15 models for a particular polynomial order was lower than that of the HET60 model in most cases. This implies that the orders of LP and types of residual variances affect the goodness of models. Also, the heterogeneity of residual variances should be considered for the test-day analysis. The heritability estimates of from the best fitted models ranged from 0.08 to 0.15 for MILK, 0.06 to 0.14 for FAT, 0.08 to 0.12 for PROT, and 0.07 to 0.13 for SNF according to days in milk of first lactation. Genetic variances for studied traits tended to decrease during the earlier stages of lactation, which were followed by increases in the middle and decreases further at the end of lactation. With regards to the fitness of the models and the differential genetic parameters across the lactation stages, we could estimate genetic parameters more accurately from RRMs than from lactation models. Therefore, we suggest using RRMs in place of lactation models to make national dairy cattle genetic evaluations for milk production traits in Korea.

• 한국산학기술학회논문지
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• 제21권8호
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• pp.67-74
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• 2020

예비군을 관리하는 현역부대의 임무 중 하나는 동원령 선포 시 예비군이 전투력을 발휘할 수 있도록 신속하게 전투물자를 지급하는 것이다. 후방지역의 현역부대는 대규모의 지역예비군을 지원하지만 운용 할 수 있는 병력이 부족하고, 많은 수량의 총기와 탄약을 부대 내부에서 통합 보관하고 있기 때문에 어려움을 가지고 있다. 이러한 이유로 지역예비군은 총기와 탄약을 통합 보관된 장소인 현역부대의 무기고와 탄약고로 이동해서 분배 받는다. 현재 군에서 사용하는 분배계획(기존 계획)은 선입선출 방식으로 분배순서가 일정하지 않다. 분배순서의 변화는 분배 완료 시간을 증가시킬 수 있고, 증가된 시간은 지역예비군의 전투력 발휘를 지연시키므로 분배 시간을 최소화 하는 것이 중요하다. 따라서 본 연구에서는 지역예비군의 총기, 탄약 분배모형을 동적계획법에 기반하여 제시하였다. 제시한 모형의 검증을 위해 후방지역 대대급 현역부대에서 수집한 실제 데이터로 현재 군에서 사용하는 분배계획과 비교하였다. 그 결과 본 연구에서 제시한 모형이 기존 계획보다 분배 완료 시간을 줄이는 우수한 성능을 보였다는 것을 알 수 있었다.

• 한국건설관리학회논문집
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• 제19권3호
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• pp.89-96
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• 2018

본 연구는 빅 데이터 분석을 통한 해외건설 빅 이슈를 도출하였다. 해외건설 Big 이슈 도출을 위하여 2016년 10월 1일부터 2017년 9월 30일 동안 주요 포털사이트 39,436건, 종합일간지 10,387건, 건설전문지 3,36건을 포함해 총 53,759건 대상으로 분석하였고, 그 주요 결과는 다음과 같다. 첫째, 지난 1년간 해외건설 주요 이슈를 살펴보면, 여전히 중동 지역에 편중되고 저가 수주 위주의 플랜트 사업이 한계점이 두드러지게 나타났다. 전년 대비 2017년 상반기, 해외건설 수주가 다소 상승하는 추세를 보이기도 했으나 대외 정세의 불확실성과 국제유가의 하락 등으로 여전히 수주 불안정성을 보인다. 둘째, 최근 1년 해외건설 관련 이슈 중 해외건설 8대 핵심 키워드 기준으로 관심사를 분석한 결과, 지역(29.9%), 기업환경(22.0%), 수익성(17.0%), 단체(15.1%), 사업(5.2%), 시장환경(3.6%), 정책 및 제도(3.6%), 교육(3.5%) 순으로 나타났다. 셋째, 8개 키워드에 대한 총 30개의 이슈 후보 중 담론의 확산성과 지속성이 있는 10대 핵심 이슈를 추출하였다. 이를 토대로 해외건설 핵심 이슈별 상세분석 및 시사점을 도출하였다. 빅 데이터 분석을 통한 해외건설 빅 이슈를 도출한 결과 4차 산업혁명 시대의 도래에 대응하고 국내 건설업계의 위기 상황을 극복할 새로운 산업 패러다임의 대전환점을 맞이해야 하며 건설산업에 고부가가치 기술을 육성하여 수익 창출을 견인해 글로벌 건설경쟁력을 키워야 한다는 시사점이 도출되었다.

• 한국중재학회지:중재연구
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• 제28권4호
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• pp.131-152
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• 2018

On October 31, 2013, the Singapore Court of Appeals handed down a landmark decision in the case of PT First Media TBK v Astro Nusantara International and Others [2013] SGCA 57. The case arose out of an arbitration in Singapore involving the Malaysian conglomerate Astro and the Indonesian conglomerate Lippo, which culminated in a USD 250 million award in favor of Astro. The final award was given to three Astro subsidiaries who were not parties to the arbitration agreement, but who were joined in the arbitration pursuant to an application by Astro. Lippo then applied to the Singapore High Court to set aside the enforcement orders. The Court of Appeals, however, reversed the High Court's decision, and found that Astro was only entitled to enforce the awards. Also, the Court of Appeals undertook a detailed analysis of the use of active and passive remedies to defeat an arbitral award at the seat and the place of enforcement, respectively. It also touches on the innovation of forced joinders of third parties in arbitrations, which have garnered significant interest in the arbitration community. This decision is therefore expected to have a significant impact on the practice of international arbitration, including in relation to how awards can be enforced or defeated, as the case may be.