• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.3
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• pp.124-132
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• 2010

In spite of the global importance of primary production of phytoplankton, some primary production data in Korean coastal waters still need to be better processed. The daily rates of water column primary production is generally estimated by integrating the primary production per unit volume over time and depth, but efforts for time integration algorithm have been conducted insufficiently. In this study a mathematical equation evaluating daily primary production integrated over time of a day is proposed and the effectiveness of the model is tested on Saemangeum Lake. The daily primary productions computed with the proposed equation were nearly the same with the results numerically integrated by substituting solar irradiance data. It was suggested that better estimation of primary production would be obtained by using monthly or weekly means of solar irradiance rather than more variable daily data. Because of the vertically heterogenous distribution of phytoplankton, it's hard to integrate the equation over depth to give the daily rates of primary production per unit area of water surface. However, the problem would be solved if, after the vertical distribution of phytoplankton was classified into several patterns and reduced to mathematical formula, every composite function of time integrated equation and chlorophyll distribution equation was integrated successfully.

• Journal of the Korean Ceramic Society
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• v.44 no.11
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• pp.607-612
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• 2007

Zn-AC and Zn-H-AC series prepared from non- and surface-modified activated carbon were investigated in terms of their hydrogen production capacity. An increase in the concentration of the zinc salts used with these series was shown to lead to a decrease in the values of the surface textural properties. The existence of zinc complexes on the surface was confirmed from an analysis of XRD data. The SEM micrographs of the two different sample types showed that the transformation of the carbon surface with an acid pre-treatment significantly change the metal contents on the surfaces of the carbon matrix. The EDX spectra indicated that all of the samples were richer in the amount of oxygen and zinc compared to any other elements. The results obtained using the Boehm's titration method showed that the positive introduction of the acidic groups on the carbon surfaces with the acid treatment is correlated with an increase in the amounts of zinc complexes with variation of the acidic groups. In terms of the hydrogen production performance, the volume fractions of the Zn-H-AC series were found to produce higher amounts than the Zn-AC series as a function of the metal contents considering the effects of the acid treatment.

• Structural Engineering and Mechanics
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• v.89 no.3
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• pp.265-281
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• 2024

The sound radiation responses of multi-layer composite plates subjected to harmonic mechanical excitation in hygrothermal environment is numerically investigated. A homogenized micromechanical finite element (FE) based on the higher-order mid-plane kinematics replicating quadratic function as well as the through the thickness stretching effect together with the indirect boundary element (IBE) scheme has been first time employed. The isoparametric Lagrangian element (ten degrees of freedom per node) is used for discretization to attain the hygro-thermo-elastic natural frequencies and the modes of the plate via Hamilton's principle. The effective material properties under combined hygrothermal loading are considered via a micromechanical model. An IBE method is then implemented to attain structure-surrounding coupling and the Helmholtz wave equation is solved to compute the sound radiation responses. The effectiveness of the model is tested by converging it with the similar analytical/numerical results as well as the experimentally acquired data. The present scheme is further hold out for solving diverse numerical illustrations. The results revealed the relevance of the current higher-order FE-IBE micromechanical model in realistic estimation of hygro-thermo-acoustic responses. The geometrical parameters, volume fraction of fiber, layup, and support conditions alongside the hygrothermal load is found to have significant influence on the vibroacoustic characteristics.

• Journal of Multimedia Information System
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• v.7 no.2
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• pp.141-146
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• 2020

Cine-Hangeul is a program that can predict the running time of a movie based on the screenplay before production. This paper seeks to verify the prediction reporting function of Cine-Hangeul, which is the standard Korean screenplay format. Moreover, this paper presents a method to increase the accuracy of the Cine-Hangeul reporting function. The objective of this paper is to offer a correction method based on scientific evidence because the current Cine-Hangeul reporting function has many errors. The verification process for five scenarios and movies confirmed that the default setting value of Cine- Hangeul's screening time prediction reporting was many errors. Cine-Hangeul analyzes the amount of textual information to predict the time of the scene and the time of the dialogue and helps predict the total time of the movie. Therefore, if a certain amount of text information is not available, the accuracy is unreliable. The current Cine-Hangeul prediction report confirms that the efficiency is high when the scenario volume is about 90 to 100 pages. As a result, prediction of screening time by Cine-Hangeul, a Korean scenario standard format program, confirmed the verification that it could secure the same level of reliability as the actual screening time by correcting the reporting settings. This verification also affirms that when applying about 50 percent of the basic set of screening time reporting, it is almost identical to the screening time.

• Journal of Korean Society of Forest Science
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• v.89 no.3
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• pp.335-341
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• 2000

In this study, the multiobjective linear programming (MOLP) formulation was built to solve for the optimal forest management planning considering carbon sequestration and timber production simultaneously. The formulation was applied to a case study problem to investigate the trends of the optimal forest harvest schedules as the function of preference of forest management for carbon sequestration and timber production. The study site was Mt. Kari area in Hongchun. The formulation includes several site-specific constraints for non-declining yields, upper and lower bounds of cut volume and area for timber, ending inventory conditions, etc.. According to the changes of weight combinations for timber production and carbon sequestration, the joint production possibilities curve was proposed as the option for management choice.

• International Journal of Precision Engineering and Manufacturing
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• v.1 no.1
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• pp.62-70
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• 2000

The design of gear train is a kind of mixed problems which have to determine various types of design variables; i,e., continuous, discrete, and integer variables. Therefore, the most common practice of optimum design using the derivative of objective function has difficulty in solving those kinds of problems and the optimum solution also depends on initial guess because there are many sophisticated constrains. In this study, the Genetic Algorithm is introduced for the optimum design of gear trains to solve such problems and we propose a genetic algorithm based gear design system. This system is applied for the geometrical volume(size) minimization problem of the two-stage gear train and the simple planetary gear train to show that genetic algorithm is better than the conventional algorithm solving the problems that have continuous, discrete, and integer variables. In this system, each design factor such as strength, durability, interference, contact ratio, etc. is considered on the basis of AGMA standards to satisfy the required design specification and the performance with minimizing the geometrical volume(size) of gear trains

• Korea Trade Review
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• v.44 no.1
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• pp.75-86
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• 2019

This study performs a factor analysis that affects the bunker oil price using the Co-integration model and Vector Error Correction Model (VECM). For this purpose, we use data from Clarkson and the analysis results show 17.6% decrease in bunker oil price when the amount of crude oil production increases at 1.0%, 10.3% increase in bunker oil price when the seaborne trade volume increases at 1.0%, 1.0% decrease in bunker oil price when total volume of vessels increases at 1.0%, and 0.003% increase in bunker oil price when 1.0% increase in world GDP, respectively. This study is meaningful in that this study estimates the speed of convergence to long-term equilibrium and identifies the price adjust mechanism which naturally exists in bunker oil market. And it is expected that the future study can provide statistically more meaningful econometric results if it can obtain data during more long-periods and use more various kinds of explanatory variables.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.4
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• pp.505-513
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• 2018

Objective: This experiment investigated the effects of aflatoxin B1 (AFB1) alone or mixed with ochratoxin A (OTA) and/or zearalenone (ZEA) on the metabolism, immune function, and antioxidant status of dairy goats. Methods: Fifty lactating Laoshan dairy goats were randomly assigned to one of five treatment groups (n = 10) for 14 days. Goats were fed no additive (control) or administered with $50{\mu}g\;AFB1/kg$ dry matter (DM) (AFB1), $50{\mu}g\;AFB1/kg$ $DM+100{\mu}g\;OTA/kg$ DM (AFB1+OTA), $50{\mu}g\;AFB1/kg$ $DM+500{\mu}g\;ZEA/kg$ DM (AFB1+ZEA), or $50{\mu}g\;AFB1/kg$ $DM+100{\mu}g\;OTA/kg$ $DM+500{\mu}g\;ZEA/kg$ DM (AFB1+OTA+ZEA). Results: Dry matter intake and milk production were lower in goats fed AFB1+OTA+ZEA than in controls. Supplementation with AFB1, OTA, and ZEA significantly decreased red blood cell count, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, and mean platelet volume, and significantly increased white blood cell count, when compared with the control group. Compared with control, the combination of AFB1, OTA, and ZEA significantly increased alanine aminotransferase (ALT) and alkaline phosphatase (ALP) activities, total bilirubin (TBIL), interleukin-6, and malondialdehyde (MDA), but significantly reduced immunoglobulin A concentration, the activities of superoxide dismutase (SOD) and glutathione peroxides (GSH-Px), and total antioxidant capacity (T-AOC) in serum. Administration of AFB1 combined with OTA led to higher ALP, ALT, TBIL, and MDA, as well as lower milk production, SOD and GSH-Px activities, and T-AOC, than administration of AFB1 combined with ZEA. Conclusion: The mixture of AFB1, OTA, and ZEA exerted the greatest adverse effects on dairy goats, meanwhile the deleterious damage of the other mycotoxin combinations were in varying degrees. The findings of this study could provide guidance for the prevention and treatment of the consequences of contamination of animal feeds with combinations of mycotoxin.

• Animal Bioscience
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• v.35 no.11
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• pp.1666-1674
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• 2022

Objective: Letrozole, a potent aromatase inhibitor, is known to have the potential to modify male reproductive function by altering sex hormone levels. This study aimed to evaluate the semen and testicular characteristics and hormonal profile of aged Mrakhoz bucks (Capra hircus) treated with letrozole. Methods: Twelve Markhoz male goats, aged between 4.5 to 5.5 years with an average body weight (BW) of 61.05±4.97 kg were used for the study. Animals were randomly divided into two equal groups and subcutaneously received either 0.25 mg/kg BW of letrozole or a control every week for 2 months. The semen collections were performed every 10 days, and blood samples and testicular biometric records were collected at 20 days intervals. Results: Letrozole causes increased testosterone and follicle-stimulating hormone levels, testosterone to estradiol ratio, semen index and reaction time during the period from 20th to 60th days (p<0.05). Furthermore, letrozole-treated bucks had higher semen volume, sperm concentration, and total sperm per ejaculate from 30th to 60th days (p<0.05). However, no differences occurred between the groups in scrotal circumference, relative testicular volume, semen pH, abnormality, acrosome integrity, and membrane integrity of sperm during the study (p>0.05). The serum luteinizing hormone levels, sperm viability, motility, and progressive motility increased, and estradiol levels decreased after 40th to 60th days of letrozole treatment (p<0.05). Conclusion: Letrozole application to aged Markhoz bucks provokes reproductive hormonal axis which, in turn, induces enhancement of semen production and quality.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.4
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• pp.386-394
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• 2012

Recent trends in the flexible manufacturing systems are morphing cell control for the shop-wide production operation system and providing the integrated operation and execution system together with vendor-specific FMC/FMS platform. In these requirements, the shop-floor level operation system plays a role of coordinating the control activity of each cell, and has to provide flexibility for the complexity of mixed operations of various cells. This paper suggests a system architecture for the mixed environments of multi-cells and job shop, its corresponding enabling technologies based on comparative studies with other related studies and commercialized systems. This approach includes a process definition model considering the integration with upper BOM-BOP and external service modules, and reconfigurable device-level interface which provides dynamic interconnections with machine tools and cell controllers. The function modules and their implementation results are also described to provide the feasibility of the proposed approaches as the flexible shop-floor operation system for the multi-cell environments.