• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.23 no.3
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• pp.211-236
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• 2019

This paper is devoted to the study and investigation of the Runge-Kutta discontinuous Galerkin method for a system of differential equations consisting of two hyperbolic conservation laws. The numerical coupling flux which is used at a given interface (x = 0) is the upwind flux. Moreover, in the linear case, we derive optimal convergence rates in the $L_2$-norm, showing an error estimate of order ${\mathcal{O}}(h^{k+1})$ in domains where the exact solution is smooth; here h is the mesh width and k is the degree of the (orthogonal Legendre) polynomial functions spanning the finite element subspace. The underlying temporal discretization scheme in time is the third-order total variation diminishing Runge-Kutta scheme. We justify the advantages of the Runge-Kutta discontinuous Galerkin method in a series of numerical examples.

• Smart Structures and Systems
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• v.22 no.6
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• pp.699-709
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• 2018

With increasing traffic volumes and rising vehicle traffic, especially in cities, the number of pedestrian bridges has also increased significantly. Like all other structures, pedestrian bridges also suffer damage. In order to increase the safety of pedestrians, it is necessary to identify existing damage and to repair them to ensure the safety of the bridge structures. Owing to the shortcomings of local methods in identifying damage and in order to enhance the reliability of detection and identification of structural faults, signal methods have seen significant development in recent years. In this research, a new methodology, based on cone-shaped kernel distribution with a new damage index, has been used for damage detection in pedestrian truss bridges. To evaluate the proposed method, the numerical models of the Warren Type steel truss and the Arregar steel footbridge were used. Based on the results, the proposed method and damage index identified the damage and determined its location with a high degree of precision. Given the ease of use, the proposed method can be used to identify faults in pedestrian bridges.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.4
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• pp.81-85
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• 1980

Field experiment was conducted to determine the optimum harvesting time in winter rape (Brassica napus L.) by investigating the percent oil, 1, 000 seed weight, seed yield, dehiscent pod ratio and oil yield at 46, 50, 54, 58, 62, 66 and 70 days after flowering. Variation of all characters with days after flowering could be explained significantly by second degree polynomial equations. Percent oil and 1, 000 seed weight increased until 62 days after flowering and thereafter these traits decreased, while seed yield increased to 58 days after flowering and thereafter this trait decreased. This controversy was due to the drastic increase in dehiscent pods beyond 58 days after flowering which brought loss in seed yield. These results suggest that optimum harvesting time is 58 days after flowering and it should not be later than 60 days after flowering.

• The Journal of Korean Medicine
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• v.43 no.3
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• pp.204-210
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• 2022

Objectives: The purpose of this case study was to report the clinical improvement of Long COVID(cough, sore throat) treated with Korean herbal medicine(Hyunggaeyungyo-tang and Saengmaek-san). Methods: To assess the treatment outcomes, I used the Visual analogue scale(VAS) to evaluate sore throat degree, and Leicester Cough Questionnaire Korean version(LCQ-K). Results: After treatments, cough and sore throat were significantly improved with VAS and LCQ-K. Conclusion: The Korean herbal medicine was effective in the treatment of patient who suffers Long COVID. This study suggested the possibility of Korean herbal medicine treatment for Long COVID.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.11
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• pp.43-49
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• 2000

In this paper, we have modeled and fabricated $1{\times}5$ equal power splitter for 1.55${\mu}m$ wavelength using finite-difference beam propagation method and $Ag^+-Na^+$ ion-exchanged method in BK7 glass, respectively. The power splitting ratio could be controlled by changing the center waveguide gap and the inner Y-branch angle. As a result, the power splitting ratio shows 0.46dB when the waveguide width, the inner Y-branch angle and the center waveguide gap are 4.5${\mu}m$, 0.3 degree and 575${\mu}m$, respectively.

• Journal of the Korean Geographical Society
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• v.39 no.5 s.104
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• pp.755-767
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• 2004

Based on a case study of bank's Automatic Teller Machines (ATMs) in Korea, this paper attempts to reveal dynamic changes occurring across the financial landscape with special emphasis on distribution pattern and location factors. Since the distribution of ATMs showed a concentrated pattern similar to that of bank branches, location quotients were examined to consider the effect of branches on ATM distribution. Furthermore, this study identified four factors that play pivotal roles in the location of ATMs. Compared to branch, location of ATM was more closely related to the population and demand factor, while the importance of local economy base and local economic power factor was reduced to some degree. This difference is attributable to the peculiar characteristic of the services offered by ATM. Lastly, demand factor turned out to be most influential in determining the ratio of ATMs to branches in each district, since lower deployment and operation costs allow ATMs to be more flexibly placed where demand for cash services is high.

• Earthquakes and Structures
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• v.19 no.4
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• pp.243-259
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• 2020

This study aims to optimize, design, and predict the MTMDs performance in SDOF systems using spectral analysis, and then apply their results to MDOF structures. Given the importance of spectral analysis in the design of new engineering structures, achieving a method for designing TMDs based on this theory can be of great importance for structural designers. In this study, several convenient combinations of MTMDs in an SDOF system are first considered to minimize the maximum displacement. For calculating the frequency ratios of dampers, an innovative technique is adopted in which the values of different modal responses obtained from the spectral analysis are approached together. This procedure is done using a harmony search (HS) algorithm. Also, using the random vibration theory, the damping ratio of the dampers is obtained. Then, an equation is presented for predicting the performance of MTMDs. For evaluating this equation, three structures with different stories are designed. Some of the presented combinations of dampers are added to them. The time history analyses are employed to analyze the structures under 30 different accelerograms. The findings indicated that the proposed equation could efficiently predict the performance of the MTMDs. Furthermore, four different patterns of damper distribution along the height of the structures are defined. The effect of them on the maximum deformation of the structures in time history analyses is discussed, and an equation is presented to estimate this effect. The results indicated that the average and maximum error percentages of the proposed equations are about three and seven percent, respectively, compared to the time history analyses results, which are negligible values.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.3
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• pp.169-180
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• 2015

Recently, scheduling problems with position-dependent processing times have received considerable attention in the literature, where the processing times of jobs are dependent on the processing sequences. However, they did not consider cases in which each processed job has different learning or aging ratios. This means that the actual processing time for a job can be determined not only by the processing sequence, but also by the learning/aging ratio, which can reflect the degree of processing difficulties in subsequent jobs. Motivated by these remarks, in this paper, we consider a two-agent single-machine scheduling problem with linear job-dependent position-based learning effects, where two agents compete to use a common single machine and each job has a different learning ratio. Specifically, we take into account two different objective functions for two agents: one agent minimizes the total weighted completion time, and the other restricts the makespan to less than an upper bound. After formally defining the problem by developing a mixed integer non-linear programming formulation, we devise a branch-and-bound (B&B) algorithm to give optimal solutions by developing four dominance properties based on a pairwise interchange comparison and four properties regarding the feasibility of a considered sequence. We suggest a lower bound to speed up the search procedure in the B&B algorithm by fathoming any non-prominent nodes. As this problem is at least NP-hard, we suggest efficient genetic algorithms using different methods to generate the initial population and two crossover operations. Computational results show that the proposed algorithms are efficient to obtain near-optimal solutions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.7
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• pp.3072-3081
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• 2011

The purpose of this study was to investigate the association of blood pressures, hematological and blood biochemical properties according to the degree of obesity based on differential combinations of BMI in health checkup examinees. Study subjects were 3,731 adults of 20 years and over (2,312 males, 1,419 females), not recognized as taking medicines for or having cardiovascular diseases, who underwent health package check-up at the Korea Association of Health Promotion, Daejeon Branch from Jan. 2007 to Dec. 2009. As a results, the mean values of SBP, DBP, TG, TC, LDL-C, ALT, AST, GGT, ALP were significantly increased with higher level of BMI, but the HDL-C was significantly decreased with higher level of BMI. On correlation of BMI with various factors, the BMI was positively correlated with SBP, DBP, TG, TC, LDL-C and GGT, while the HDL-C was negatively correlated. Based on the result of ordinal logistic regression analysis, the risk ratio to the abnormal level of SBP, DBP, TG, ALT and GGT were significantly increased as BMI increased.

• Journal of Life Science
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• v.26 no.5
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• pp.519-530
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• 2016

Vegetative plants in Yakutia are naturally frozen when they are covered with snow in the fall, and they function as green cryo-fodder that is a source of biologically active substances and nutrients for herbivorous animals. We observed a considerable increase in the total fatty acid content in the leaves of Avena sativa, Elytrigia rеpens, Equisetum variegatum and Equisetum scirpoides during the fall period. However, the degree of unsaturation of fatty acids was not higher in the frozen plants covered with snow than in the summer plants, with the exception of E. scirpoides, a dwarf horsetail found in the Pole of Cold in the northern hemisphere. In the internal adipose tissue of the Yakut horse (young horse meat), 18 fatty acids were found, including 10 saturated ones. Monounsaturated oleic С18:1 (n-9) acid and polyunsaturated α-linolenic С18:3 (n-3) acid were equally prevalent among the unsaturated fatty acids, accounting for 70% of the total unsaturated fatty acids. This composition of polyenoic fatty acids in the internal adipose tissue indicates that the Yakut horse actively feeds on the fall vegetation and the wintergreen sedge-grass. We believe that the high plant-specific free fatty acid content in the tissue of Yakut horses may play an important role in the regulation of their resistance to long-term low-temperature stress.