• Journal of Animal Science and Technology
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• v.65 no.3
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• pp.588-595
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• 2023

The aim of this study was to investigate the effects of heat stress on milk traits in South Korea using comprehensive data (dairy production and climate). The dataset for this study comprised 1,498,232 test-day records for milk yield, fat- and protein-corrected milk, fat yield, protein yield, milk urea nitrogen (MUN), and somatic cell score (SCS) from 215,276 Holstein cows (primiparous: n = 122,087; multiparous: n = 93,189) in 2,419 South Korean dairy herds. Data were collected from July 2017 to April 2020 through the Dairy Cattle Improvement Program, and merged with meteorological data from 600 automatic weather stations through the Korea Meteorological Administration. The segmented regression model was used to estimate the effects of the temperature-humidity index (THI) on milk traits and elucidate the break point (BP) of the THI. To acquire the least-squares mean of milk traits, the generalized linear model was applied using fixed effects (region, calving year, calving month, parity, days in milk, and THI). For all parameters, the BP of THI was observed; in particular, milk production parameters dramatically decreased after a specific BP of THI (p < 0.05). In contrast, MUN and SCS drastically increased when THI exceeded BP in all cows (p < 0.05) and primiparous cows (p < 0.05), respectively. Dairy cows in South Korea exhibited negative effects on milk traits (decrease in milk performance, increase in MUN, and SCS) when the THI exceeded 70; therefore, detailed feeding management is required to prevent heat stress in dairy cows.

• Convergence Security Journal
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• v.8 no.3
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• pp.83-92
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• 2008

In respect complication of group and period, the sales of retail trade is composed of various factors. This paper studies focus on estimating the determinants of the sales of retail trade. The volume of analysis consist of 7 groups. Analyzing period be formed over a 36 point(2005. 1$\sim$2007. 12). In this paper dependent variable setting up sales of retail trade, explanatory(independent) variables composed of composite stock price index, the number of the consumer's online buying behavior company, the coincident composite index, the index of trading price of APT, employment rate, an average of the rate of operation(the manufacturing industry), the consumer price index. The result of estimating the determinants of sales of retail trade provides empirical evidences of significance positive relationships between the coincident composite index, the index of trading price of APT, employment rate, an average of the rate of operation(the manufacturing industry). However this study provides empirical evidences of significance negative relationships between the consumer price index. The explanatory variables, that is, composite stock price and the number of the consumer's online buying behavior company, are non-significance variables. Implication of these findings are discussed for content research and practices.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.272-277
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• 2010

In respect complication of group, rate of arrearage in domestic bank is composed of various factors. This paper studies focus on estimating the determinants of the rate of arrearage in domestic bank using panel data model. The volume of analysis consist of 3 groups(loaned patterns of enterprise, housekeeping, credit card). Analyzing period be formed over a 54 point(2005. 1~ 2009. 06). In this paper dependent variable setting up rate of arrearage in domestic bank, explanatory(independent) variables composed of the consumer price index, composite stock price index, rate of exchange, the coincident composite index, national housing bonds and employment rate. The result of estimating the rate of arrearage in domestic bank provides empirical evidences of significance positive relationships between the consumer price index However this study provides empirical evidences of significance negative relationships between the coincident composite index and the composite stock price index. The explanatory variables, that is, rate of exchange, national housing bonds and the employment rate are non-significance variables of negative factor. Implication of these findings are discussed for content research and practices.

• Korean Journal of Optics and Photonics
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• v.8 no.3
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• pp.245-249
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• 1997

An electro-optic polymer digital optical switch with a coupling region modified for optimum coupling is designed and demonstrated. Its branch waveguide is fabricated by reactive ion etching. Then, the modified coupling region is adiabatically introduced along the propagation direction from the branching point of the two waveguides, and it is implemented by photobleaching after the device fabrication. The structure of the modified coupling region and its refractive index profiles are designed to optimize and mode coupling in the Y-branch waveguide. Therefore, the switching performance of the device was shown to be enhanced with a fixed device length. The measured drive voltage is reduced by more than 30 percents, and the crosstalk is also improved by about 4~6 dB.

• Journal of the Korea Concrete Institute
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• v.28 no.1
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• pp.13-21
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• 2016

A hybrid precast concrete beam system with a simple rigid connection was proposed to compensate the limitations and shortcomings of the conventional bolt connection associated with the H-beams embedded into concrete beams. Three beam specimens with fixed both ends were tested under one-point top cyclic loading to explore the effectiveness of the developed hybrid beam system in transferring externally applied flexure to a column. The main parameter considered was the length ($L_s$) of H-beam, which was selected to be $0.25L_I$, $0.5L_I$, and $1.0L_I$, where $L_I$ is the distance from the support to the point of inflection. All beam specimens showed a better displacement ductility ratio than the reinforced concrete beams with the same longitudinal reinforcement index, indicating that the cyclic load-deflection curve and ductility were insignificantly affected by $L_s$. The continuous strain distribution along the beam length and the prediction of the ultimate load based on the collapse mechanism ascertained the structural adequacy of the developed rigid connection.

• Toxicological Research
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• v.27 no.4
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• pp.247-251
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• 2011

To clarify whether inhibitory effect of estrogen on liver tumor is associated with cell proliferation, we investigated its role in diethylnitrosamine (DEN)-induced rat preneoplastic lesions, with time sequenced manners. F344 male rats (n = 90) were divided into three groups at 5 weeks of age. The mini-osmotic pumps providing a continuous infusion of DEN was implanted into the abdominal cavity of each animal in group 1, 2 and 3 at 6 weeks of age. To see the effect of estrogen, pellet containing 1 or 10 ${\mu}g$ of estradiol-3-benzoate (EB) was implanted subcutaneously in the animals of groups 2 or 3, respectively, one week prior to DEN treatment. Ten animals of each group were euthanized at 10, 14 and 18 weeks after DEN treatment. Liver tissues at each time point were fixed in 10% phosphate-buffered formalin and were processed and embedded in paraffin and 5 ${\mu}g$ sections mounted on a silanized slide. Glutathione S-transferase placental form (GST-P) positive foci and 5-bromo-2-deoxyuridine (BrdU) labeling cells were detected at each time point. Area of GST-P positive foci in DEN+EB 1 or 10 ${\mu}g$ group was significantly decreased compared to DEN alone at 14 weeks (p < 0.01 or p < 0.05, respectively) an at 18 weeks (p < 0.05 or p < 0.01, respectively). BrdU index in DEN+EB 1 or 10 ${\mu}g$ groups was significantly decreased compared to DEN alone at 14 weeks and at 18 weeks (p < 0.01). Taken together, we conclude that EB treatment decrease the DEN-induced liver preneoplastic lesions and this may be associated with decrease of cellular proliferation.

• The korean journal of orthodontics
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• v.35 no.5 s.112
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• pp.381-387
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• 2005

The aim of this study was to compare the clinical performance of 4 types of orthodontic wires, indicated for initial tooth alignment: stainless steel, multistranded steel, superelastic and thermoactivated nickel-titanium. A prospective randomized clinical trial was conducted on a sample of 45 patients, at the Dental School of the State University of Rio do Janeiro, Brazil. Fixed appliances were fitted and study casts were obtained from each patient. Randomly, the wires were allocated as follows: 26 dental arches for superelastic NiTi wires, 22 for stainless steel, 22 for multistranded and 20 for thermoactivated archwires. After 8 weeks, the archwires were removed and impressions for study casts were taken again. Using a 3D digitization technique of defined anatomical points on the study cast crowns, a Dental Irregularity Index (DII) was created for each study cast. The difference between DII before and after the archwire insertion expressed the aligning effect of the wires. ANOVA tests were employed to evaluate the anatomical point approximation (positive DII) and separation (negative DII), for each area of the dental arches: upper and lower whole arch and anterior arch. Results showed no significant difference between the different archwires.

• Journal of the Korea Society of Computer and Information
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• v.13 no.4
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• pp.231-240
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• 2008

In respect complication, group and period, the foreign direct investment of korea is composed of various factors. This paper studies focus on estimating the determinants of foreign direct investment of korea. The region of analysis consist of 7 groups, that is, Asia, Europe, Central and South America, Oceania, Africa, Middle East. Analyzing period be formed over a 67 point(2002. 6${\sim}$2007. 12). In this paper dependent variable setting up an amount of foreign direct investment, explanatory(independent) variables composed of gross domestic product, a balance of current accounts, the foreign exchange rate, employment to population ratio, an average of the rate of operation(the manufacturing industry), consumer price index, the amount of export, wages(a service industry). For an actual proof analysis, LIMDEP 8.0 software, analysis model is random effect in TWECR The result of estimating the determinants of foreign direct investment of korea provides empirical evidences of significance positive relationships between employment to population ratio and wages(a service industry). However this study provides empirical evidences of significance negative relationships between the foreign exchange rate, censurer price index and the amount of export. The explanatory variables, that is, an average of the rate of operation(the manufacturing industry), gross domestic product and a balance of current accounts, are non-significance variables.

• Journal of Korean Neurosurgical Society
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• v.60 no.5
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• pp.604-609
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• 2017

Objective : An adjustable Ghajar guide is presented to improve the accuracy of the original Ghajar guide technique. The accuracy of the adjustable Ghajar guide technique is also investigated. Methods : The coronal adjustment angle from the orthogonal catheter trajectory at Kocher's point is determined based on coronal head images using an electronic picture archiving and communication system. For the adjustable Ghajar guide, a protractor is mounted on a C-shaped basal plate that is placed in contact with the margin of a burrhole, keeping the central $0^{\circ}$ line of the protractor orthogonal to the calvarial surface. A catheter guide, which is moved along the protractor and fixed at the pre-determined adjustment angle, is then used to guide the ventricular catheter into the frontal horn adjacent to the foramen of Monro. The adjustable Ghajar guide technique was applied to 20 patients, while a freehand technique based on the surface anatomy of the head was applied to another 47 patients. The accuracy of the ventricular catheter placement was then evaluated using postoperative computed tomography scans. Results : For the adjustable Ghajar guide technique (AGT) patients, the bicaudate index ranged from 0.23 to 0.33 ($mean{\pm}standard$ deviation [SD] : $0.27{\pm}0.03$) and the adjustment angle ranged from $0^{\circ}$ to $10^{\circ}$ ($mean{\pm}SD:5.2^{\circ}{\pm}3.2^{\circ}$). All the AGT patients experienced successful cerebrospinal fluid diversion with only one pass of the catheter. Optimal placement of the ventricular catheter in the ipsilateral frontal horn approximating the foramen of Monro (grade 1) was achieved in 19 patients (95.0%), while a suboptimal trajectory into a lateral corner of the frontal horn passing along a lateral wall of the frontal horn (grade 3) occurred in 1 patient (5.0%). Thus, the AGT patients experienced a significantly higher incidence of optimal catheter placement than the freehand catheterized patients (95.0% vs. 68.3%, p=0.024). Moreover, none of the AGT patients experienced any tract hemorrhages along the catheter or procedure-related complications. Conclusion : The proposed adjustable Ghajar guide technique, using angular adjustment in the coronal plane from the orthogonal trajectory at Kocher's point, facilitates accurate freehand placement of a ventricular catheter for hydrocephalic patients.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.6
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• pp.633-641
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• 2015

Several complex processes that are employed in industries, such as shipping, power plants, and the petrochemical industry, involve time-varying behavior as well as strong nonlinear behavior during operation. The fixed-parameter proportional-integral-derivative (PID) controllers have difficulty in dealing with control problems that occur in such processes. In this paper, we propose a method of designing a nonlinear PID controller for industrial processes that exhibit a large number of nonlinearities and time-varying behavior. The gains of the nonlinear PID controller are characterized by a simple nonlinear function of the error and/or error rate depending on the process set-point and output. We tune the user-defined parameters using a genetic algorithm by minimizing the integral of time absolute error (ITAE) index. We verify the effectiveness of the proposed method by performing a comparison of the proposed method and two other nonlinear and adaptive methods that are employed for reference tracking, disturbance-rejection performances, and robustness to parameter changes on a continuously stirred tank reactor.