• Bulletin of the Korean Chemical Society
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• v.13 no.3
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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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• v.44 no.3
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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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• v.16 no.1
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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.

• Korean Journal of Environmental Biology
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• v.39 no.4
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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.

• Bulletin of the Korean Mathematical Society
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• v.60 no.3
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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.

• Korean Journal of Optics and Photonics
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• v.16 no.1
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• pp.34-42
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• 2005

This paper presents the optimum initial design containing the first and third order properties of the three-group zoom system using lens modules, and the real lens design of the system. The optimum initial design with focal length range of 4.3 mm to 8.6 mm is derived by assigning appropriate first and third order quantities to each module along with the specific constraints required for the system. An initial real lens selected for each group has been designed to match its focal length and the first orders into those of the each lens modules, and then combined to establish an actual zoom system by adjusting the air space between the groups at all zoom positions. The combination of the separately designed groups results in a system which satisfies the first order properties of the zoom system composed of the original lens modules. As a result, by residual aberration correction, we could obtain a zoom system useful in compact digital zoom cameras and mobile phone cameras employing the rear focus method.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.5
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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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.67-74
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• 2020

One of the missions of active-duty units in charge of managing reserve forces is providing combat supplies to reserve forces to exercise their combat capabilities quickly when declaring a mobilization order. Rear area active-duty units must support large local reserve forces. On the other hand, military units have difficulties due to a lack of forces and the storage of large quantities of firearms and ammunition. For this reason, local reserve forces should move to an integrated storing place and receive their firearms and ammunition. The existing distribution plan (existing plan) is a first-in-first-out plan that can produce inconsistent distribution orders. The inconsistent distribution orders can increase the complete distribution time, which will affect the combat power of local reserve forces. Therefore, firearms and ammunition should be distributed quickly. Accordingly, this paper proposes the priority selection of firearms and ammunition for local reserve forces with a minimum complete distribution time using Dynamic Programming. To verify the proposed model, the existing plan was compared with the proposed model using real data, and the result showed that the proposed model outperformed the existing plan.

• Korean Journal of Construction Engineering and Management
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• v.19 no.3
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• pp.89-96
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• 2018

This study derived big issues in overseas construction through big data analysis. To derive big issues in overseas construction, candidate groups of big issues were identified through big data analysis targeting 53,759 issues including 39,436 issues from major portal sites, 10,387 issues from daily newspapers, and 336 issues in construction magazines from Oct. 1, 2016 to Sep. 30, 2017. The main results are as follows: First, the main issues of overseas construction for the past one year showed that markets were concentrated in Middle East Asia and most of them were low-price order plant projects, which revealed the limitations. Although orders of overseas construction were slightly upward in the first half of 2017 compared to previous year, overseas construction orders are still unstable due to uncertainties in the international affairs and drops in oil prices. Second, the interest topics based on the 8th core keywords of overseas construction among the overseas construction issues for the past one year showed that region (29.9%), corporation environment (22.0%), profitability (17.0%), organizations (15.1%), projects (5.2%), market environment (3.6%), policy and system (3.6%), and education (3.5%) in the order of interest. Third, 10 core issues that have expandability and persistence of discourse were extracted out of 30 issue candidates with regard to eight keywords. Based on the extracted issues, detailed analysis on each of the core issues in overseas construction and correlation analysis between 10 core issues were conducted.

• Journal of Arbitration Studies
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• v.28 no.4
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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.