• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.453-459
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• 2021

The system marginal price of electricity is the amount paid to all the generating units, which is an important decision-making factor for the construction and maintenance of an electrical power unit. In this paper, we suggest a long-term forecasting model for calculating the system marginal price based on prices of natural gas and oil. As most variables used in the analysis are nonstationary time series, the long run relationship among the variables should be examined by cointegration tests. The forecasting model is similar to an error correction model which consists of a long run cointegrating equation and another equation for short run dynamics. To mitigate the robustness issue arising from the relatively small data sample, this study employs various testing and estimating methods. Compared to previous studies, this paper considers multiple fuel prices in the forecasting model of system marginal price, and provides greater emphasis on the robustness of analysis. As none of the cointegrating relations associated with system marginal price, natural gas price and oil price are excluded, three error correction models are estimated. Considering the root mean squared error and mean absolute error, the model based on the cointegrating relation between system marginal price and natural gas price performs best in the out-of-sample forecast.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.1
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• pp.153-160
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• 2022

This study presents the bogie arrangement of the load-out system for on-ground shipbuilding. The load-out system is one of the most important systems to perform the bogie arrangement of the on-ground shipbuilding technique without dry dock facilities, and this system is composed of four pieces of equipment: bogies, driving bogie with motors, trestles, and power packs. Also, the bogie arrangement analysis (BAA) is employed to simply calculate the reaction forces at the trestle for structural safety. In this context, the purpose of this study is to propose an optimal design method to perform the bogie arrangement satisfying structural safety requirements with minimal cost. It is expected that the proposed methodology will contribute to the effective practice as well as to the improvement of competitive capability for shipbuilding companies at the on-ground shipbuilding stage. Furthermore, we describe some problems and their solutions of the deformation that may occur in the bottom of the hull during the load-out process. As a result, it is shown that we applied it to the 114K crude oil tanker (Minimum bogie 54EA) and the 174K CBM LNG carrier (Minimum bogie 88EA), it can minimize the number of bogie and critical risks (Safety rate 1.61) during the load-out of on-ground shipbuilding. Through this study, the reader will be able to learn successful load-out operation and economic shipbuilding in the future.

• Journal of Animal Science and Technology
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• v.48 no.1
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• pp.9-14
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• 2006

Milk yield and its quality traits determine the dairy enterprise profitability and sustainability. Milk quality traits including somatic cell counts (SCC) is an upcoming economic challenge for dairy farming community in Korea. This study estimated the effect of parity, stage of lactation (early, mid and late lactation) on SCC, stress (blood cortisol) and immunity (blood IgG, lymphocyte and neutrophil) traits, their heritabilities and genetic correlations between them. SCS and blood neutrophil count were significantly affected by both parity and stage of lactation, however; IgG was affected by only stage of lactation, and blood cortisol and lymphocyte were not affected by both factors. The SCS has shown increasing trend with the parity, however; the difference between first and second parity, second and third parity were not significant. The SCS in early (≤90 days) and late lactation (181≤days) were higher than that of mid lactation (91～180 days). Cortisol concentration in blood was lowest in fourth parity, however; the differences among the first three parties were not significant. The IgG was higher in fourth parity compare with first parity however; all other comparisons were noted non-significant. The IgG concentration was significantly higher in early lactation than those of mid and late lactation. The blood lymphocytes were decreased with increasing parity however the differences beyond second parity were not significant. The neutrophils were increased with the increasing lactation stage however; the difference between early and mid lactation was not significant. Although heritability of SCS was still lower, but it was meaningful value (0.09) and may be considered to improve milk quality. The genetic correlations between SCS and cortisol (-0.96), and lymphocyte (-0.76) were highly negative. Heritability of cortisol was low, however genetic correlations between cortisol and lymphocyte (0.79) was highly positive. IgG with medium heritability was correlated negatively with lymphocyte (-0.88) and neutrophil (-0.98). Lymphocyte was lowly heritable and highly correlated with neutrophil concentration (0.87).This study suggested that cortisol, IgG, lymphocyte and neutrophil being positively genetically correlation with somatic cell score could be used as alternative traits to enhance milk quality in Holstein cattle. Further studies are warranted to estimate genetic relationships between immunological and production traits to increase the genetic merit of Holstein cows for milk yield, to improve animal health and economic viability under intensive management system.

• Journal of Dairy Science and Biotechnology
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• v.34 no.4
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• pp.255-262
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• 2016

This study was conducted to investigate the difficulties of dairy farms in practicing 6th industrialization and methods for overcoming these difficulties. A qustionnaire survey was carried out to examine the present states of farms, recognition of the farmstead milk-processing market situation, possibility of farmstead milk processing for reducing the raw milk surplus, assessment of government policies, and difficulties dairy farmers confront in realizing the 6th industrialization. Farm sizes, types, and human resources organizations varied between farms. Most farmers were producing yogurt and/or fresh (string or barbecue) cheeses, which were marketed through 'Visit and Purchase' channel. Farmers who answered the questionnaire were relatively positive about the current situation of farmstead milk processing, expecting to be involved in the disposal of excess raw milk. Nevertheless, they responded negatively about current relevant policies, citing the main difficulties caused by 'excessive regulation'. Other barriers to successful '6th industrialization' are difficulties in marketing and lack of funds. Approximately 19% of dairy farms practicing the '6th industrialization' use automatic milking system (AMS) and 38.46% of dairy farmers whose milking depends on conventional milking system intend to introduce AMS in the future. Positive expectations of AMS adoption were mostly related to 'lack of time and labor', 'exhibiting for tourism', and 'succession of dairying'.

• Analytical Science and Technology
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• v.11 no.1
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• pp.62-72
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• 1998

This study was performed to characterize the trace organic pollutants in the industrial wastewater and to establish the database of the trace organic pollutants. The four manufacturing industries, which are refined petroleum, industrial chemicals, rubber & plastics and fabricated metals, were surveyed. The wastewater and discharging water of these 30 factories are analyzed to characterize the trace organic pollutants. In industrial chemicals, the kinds of products and organic pollutants are very various. Therefore to select the characteristic organic pollutants in this categories are also very difficult. In industrial chemicals, the gas chromatograpic peak patterns of wastewater are represented the various type according to their products, therefore the typical patterns of the characteristic organic pollutants could not be obtained because the kinds of manufactured goods and organic pollutants are very various. In refined petroleum, the effluent is discharged in the distillatory process of atmosphere pressure and contained the saturated hydrocarbons, phenol compounds, benzene compounds and naphtalene compounds. The saturated hydrocarbons peaks from $C_{15}$ to $C_{35}$ are represented the typical oil patterns by the uniform intervals therefore the peak can be easily distinguished. In rubber & plastics, the wastewater is discharged in the washing process which contains the additives. The problem of wastewater is not serious because the manufacturing process is not produced the effluent or the produced cooling water is recycled in that process.

• Journal of Life Science
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• v.33 no.7
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• pp.565-573
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• 2023

In light of the complex interactions between the host animal and its resident gut microbiomes, studies of these microbial communities as a means to improve cattle production are important. This study was conducted to analyze the intestinal microorganisms of Holstein (HT) and Jersey (JS), raised in Korea and to clarify the differences in microbial structures according to cattle species through next-generation sequencing. The alpha-diversity analysis revealed that most species richness and diversity indices were significantly higher in JS than in HT whereas phylogenetic diversity, which is the sum of taxonomic distances, is not significant. Microbial composition analysis showed that the intestinal microbial community structure of the two groups differed. In the both groups, a significant correlation was observed among the distribution of several microbes at the family level. In particular, a highly significant correlation (p<0.0001) among a variety of microbial distributions was found in JS. Beta-diversity analyis was to performed to statistically verify whether a difference exists in the intestinal microbial community structure of the two groups. Principal coordinate analysis and unweighted pair group method with arithmetic mean (UPGMA) clustering analysis showed separation between the HT and JS clusters. Meanwhile, permutational multivariate analysis of variance (PERMANOVA) revealed that their microbial structures are significantly different (p<0.0001). LEfSe biomarker analysis was performed to discover the differenc microbial features between the two groups. We found that several microbes, such as Firmicutes, Bacilli, Moraxellaceae and Pseudomonadales account for most of the difference in intestinal microbial community structure between the two groups.

• Journal of Intelligence and Information Systems
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• v.24 no.2
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• pp.195-220
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• 2018

In this study, we conducted an empirical analysis of the factors that affect the change of Bitcoin Closing Price. Previous studies have focused on the security of the block chain system, the economic ripple effects caused by the cryptocurrency, legal implications and the acceptance to consumer about cryptocurrency. In various area, cryptocurrency was studied and many researcher and people including government, regardless of country, try to utilize cryptocurrency and applicate to its technology. Despite of rapid and dramatic change of cryptocurrencies' price and growth of its effects, empirical study of the factors affecting the price change of cryptocurrency was lack. There were only a few limited studies, business reports and short working paper. Therefore, it is necessary to determine what factors effect on the change of closing Bitcoin price. For analysis, hypotheses were constructed from three dimensions of consumer, industry, and macroeconomics for analysis, and time series data were collected for variables of each dimension. Consumer variables consist of search traffic of Bitcoin, search traffic of bitcoin ban, search traffic of ransomware and search traffic of war. Industry variables were composed GPU vendors' stock price and memory vendors' stock price. Macro-economy variables were contemplated such as U.S. dollar index futures, FOMC policy interest rates, WTI crude oil price. Using above variables, we did times series regression analysis to find relationship between those variables and change of Bitcoin Closing Price. Before the regression analysis to confirm the relationship between change of Bitcoin Closing Price and the other variables, we performed the Unit-root test to verifying the stationary of time series data to avoid spurious regression. Then, using a stationary data, we did the regression analysis. As a result of the analysis, we found that the change of Bitcoin Closing Price has negative effects with search traffic of 'Bitcoin Ban' and US dollar index futures, while change of GPU vendors' stock price and change of WTI crude oil price showed positive effects. In case of 'Bitcoin Ban', it is directly determining the maintenance or abolition of Bitcoin trade, that's why consumer reacted sensitively and effected on change of Bitcoin Closing Price. GPU is raw material of Bitcoin mining. Generally, increasing of companies' stock price means the growth of the sales of those companies' products and services. GPU's demands increases are indirectly reflected to the GPU vendors' stock price. Making an interpretation, a rise in prices of GPU has put a crimp on the mining of Bitcoin. Consequently, GPU vendors' stock price effects on change of Bitcoin Closing Price. And we confirmed U.S. dollar index futures moved in the opposite direction with change of Bitcoin Closing Price. It moved like Gold. Gold was considered as a safe asset to consumers and it means consumer think that Bitcoin is a safe asset. On the other hand, WTI oil price went Bitcoin Closing Price's way. It implies that Bitcoin are regarded to investment asset like raw materials market's product. The variables that were not significant in the analysis were search traffic of bitcoin, search traffic of ransomware, search traffic of war, memory vendor's stock price, FOMC policy interest rates. In search traffic of bitcoin, we judged that interest in Bitcoin did not lead to purchase of Bitcoin. It means search traffic of Bitcoin didn't reflect all of Bitcoin's demand. So, it implies there are some factors that regulate and mediate the Bitcoin purchase. In search traffic of ransomware, it is hard to say concern of ransomware determined the whole Bitcoin demand. Because only a few people damaged by ransomware and the percentage of hackers requiring Bitcoins was low. Also, its information security problem is events not continuous issues. Search traffic of war was not significant. Like stock market, generally it has negative in relation to war, but exceptional case like Gulf war, it moves stakeholders' profits and environment. We think that this is the same case. In memory vendor stock price, this is because memory vendors' flagship products were not VRAM which is essential for Bitcoin supply. In FOMC policy interest rates, when the interest rate is low, the surplus capital is invested in securities such as stocks. But Bitcoin' price fluctuation was large so it is not recognized as an attractive commodity to the consumers. In addition, unlike the stock market, Bitcoin doesn't have any safety policy such as Circuit breakers and Sidecar. Through this study, we verified what factors effect on change of Bitcoin Closing Price, and interpreted why such change happened. In addition, establishing the characteristics of Bitcoin as a safe asset and investment asset, we provide a guide how consumer, financial institution and government organization approach to the cryptocurrency. Moreover, corroborating the factors affecting change of Bitcoin Closing Price, researcher will get some clue and qualification which factors have to be considered in hereafter cryptocurrency study.

• Journal of Embryo Transfer
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• v.19 no.2
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• pp.127-132
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• 2004

Ninety-two heads of sire, ranging from 4 to 8 years old, and semen production records of 8,628 from those sire and the performance and carcass traits from 814 heads of those offspring were used to investigate the relationships of scrotal circumference(SC) of Hanwoo sire to semen characteristics and performance, carcass traits of those offspring. Average SC of sire were 38.7 cm. The semen volume, sperm concentration and total sperm number at first and second ejaculation were 5.63 mL and 5.32 mL, $17.9{\times}108/mL$ and 15.0${\times}10^8$/mL, and 100.3${\times}10^8$/ ejaculation and 79.4${\times}10^8$/ejaculation, respectively. SC is positively correlated with semen volume(1st : ${\gamma}$=0.27, P<0.05 ; 2nd : ${\gamma}$=0.19, P<0.10), sperm concentration(1st : ${\gamma}$=0.21, P<0.05) and total sperm number(1st $:{\gamma}=0.38$, 2nd : ${\gamma}$=0.28, P<0.01). The live weights of those offspring were 49.2, 281.1, 436.3 and 534.4 kg at 6, 12, 18, 22 months old, respectively, and average daily gain(ADG) were 0.81 kg/day. And, carcass weight, longissimus dorsi area, backfat thickness and marbling score were 313.8 kg, 77.9 cm, 0.62 cm and 2.47, respectively. There were tended to be positive relationships between SC of sire and live weight of 6 months old(${\gamma}$=0.08, P<0.10), 12(${\gamma}$=0.18, P=0.10), 18(${\gamma}$=0.21, P<0.10), 22(${\gamma}$=0.20, P<0.10), ADG(${\gamma}$=0.25, P<0.05), carcass weight(${\gamma}$=0.18, P<0.10) and longissimus dorsi area(${\gamma}$=0.18, P<0.10) of those offspring. However, SC and backfat thickness, marbling score have no significant relationship. This results indicate that SC of sire was related to semen production and the gain weight of those offspring, positively. However, further investigation are needed to confirm the results.

• Journal of Animal Science and Technology
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• v.52 no.1
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• pp.9-16
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• 2010

A previous study has shown that the g.17924G>A polymorphism of fatty acid synthase (FASN) is associated with unsaturated fatty acid composition in the Hanwoo beef, hence this study was conducted to evaluate the effect of single nucleotide polymorphisms (SNPs) within FASN gene on the selection phenotypes of Hanwoo breeding stock. A total of 925 progeny test steers were used to genotype g.11280G>A, g.13125T>C, and g.17924G>A polymorphisms and significant associations were found among g.11280G>A, g.17924G>A, and carcass traits, such as carcass weight, backfat thickness, and beef quantity index. No significant association was found between g.13125T>C and carcass traits. Although the degree of linkage disequilibrium (LD) was not strong among g.11280G>A, g.13125T>C, and g.17924G>A in the LD analysis, four major haplotype classes were formed with the genotypic information within the FASN gene; the frequencies of the halpotypeswere -GCG-[0.378], -ATG-[0.301], -GTA-[0.191], and -ACG-[0.063], respectively. Phenotypic association was performed among these haploptypes, and the haplotype 2 (-ATG-)was significantly associated with higher carcass weight when compared to the other haplotypes, i.e. haplotype 1 (-GCG-) and haplotype 3 (-GTA-). A copy number of the FASN haplotype 3 (-GTA-) had also a significant association with carcass weight of subjects. In conclusion, it was observed that two polymorphisms (g.11280G>A and g.17924G>A) and their haplotypes within the FASN gene are consistently associated with carcass traits. Therefore, it is desirable to use the FASN polymorphisms for pre-selection program as genetic marker with improved carcass yield and beef quality of the Hanwoo sire at the Hanwoo Improvement Center as well as for commercial Hanwoo producers, the FASN genotypic information can be used for a part of selecting Hanwoo dam for superior calf production.

• Food Science of Animal Resources
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• v.29 no.4
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• pp.437-444
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• 2009

${\gamma}-Aminobutyric$ acid (GABA) producing lactic acid bacteria, Lactobacillus acidophilus RMK567 was cultivated in 50 L of sterilized MRS broth using a fermenter at $40^{\circ}C$ for 24 h. The cell number was increased to $10.04{\pm}0.13$ Log CFU/mL with a growth rate constant (k) of 0.454 generation/h and a generation time (g) of 2.303 h after a lapse of a lag phase (L) of 5.16 h. A total of 487 g of cell paste with 40.5% moisture was harvested with viable cell number of 12.48 Log CFU/g cell paste. The cell pastes after preparation with glycerol, glucose, and polydextrose as cryo-protectants were lyophilized under a vacuum of 84 m torr. A total of 408 g of freeze dried (FD) cell powders were mixed with a commercial strain of Streptococcus thermophilus to prepare of three types FD starter cultures with the viable cell numbers of 12.42 (FDA-GY), 12.60 (FDBGG) and 12.91 (FDC-GP) Log CFU/g. During preservation the FD cultures at -$18^{\circ}C$, the cell viability of the FD starter cultures were rapidly dropped to below 3.24% of the day of storage. No significant difference was found in the cell viabilities among three types of FD starters cultures, but significant difference (p<0.01) was found in storage periods. Yoghurts fermented through FD starter culture of L. acidophilus RMK567 were determined to contain $155.16{\pm}8.53$ ppm, $243.82{\pm}4.27$ ppm, and $198.64{\pm}23.46$ ppm of GABA, respectively. This study shows that GABA production activity of L. acidophilus RMK567 is not affected during the freeze drying process and would be available for commercial production of yoghurt containing high GABA content.