• Animal Bioscience
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• v.36 no.6
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• pp.869-878
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• 2023

Objective: Hyperketonemia remains a major metabolic issue of serious milk production and a major health concern in early lactation cows. Oral supplementation of glucose precursors (GP) can be used to prevent hyperketonemia in dairy cows. The objective of this study was to compare the beneficial effects of orally supplementing a mixture of GP on metabolic health indicators and milk production status of primiparous (PP) and multiparous (MP) dairy cows. Methods: Twenty-eight Holstein cows were blocked by expected date of parturition, previous lactation yield, and parity. The cows were randomly allocated to one of the four treatment groups (n = 7 cows/group) based on their parity and GP supplementation: i) PP cows fed basal diet only (PP-CON), ii) PP cows with oral supplementation of GP (PP-GP), iii) MP cows fed basal diet only (MP-CON), and iv) MP cows with oral supplementation of GP (MP-GP). Glucose precursor (glycoline liquid) was orally drenched (300 mL/d) in GP cows from 7 days prepartum through 7 days postpartum. Other than GP supplementation, all cows were fed similar pre- and postpartum basal diets. Results: In both pre- and postpartum periods, serum glucose concentration was increased, whereas β-hydroxybutyrate and free fatty acids were decreased in GP cows compared with the CON cows. Milk yield and milk components were statistically not different between GP and CON cows over the first 9 week of lactation. The yield of actual milk, energy-corrected milk, 63-days cumulative milk, colostrum yield, and calf birth weight remained higher in MP cows compared with PP cows. Conclusion: Oral drenching of GP around calving can be recommended to successfully improve the metabolic health and reduce the negative effects of hyperketonemia not only in MP but also in PP dairy cows.

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.312-318
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• 2023

In recent years, fine and yellow dust pollution has become serious in Korea and has negatively affected crop production. Particulate matter (PM) adheres to greenhouse coverings, and it reduces the amount of solar radiation transmitted into a greenhouse. A reduction in light transmittance can have a direct effect on crop photosynthesis and an indirect effect on air temperature in a greenhouse, which can lead to differences in crop yield. The objectives of this study were to investigate the changes in light transmittance of different cover materials by PM and to determine the changes in cucumber growth in a greenhouse due to reduced light transmittance. We measured the changes in light transmittance of polyethylene (PE) and polyolefin (PO) films in the PM generation chambers. Also, cucumber plants were cultivated in a greenhouse with four different light reduction treatments (0, 10, 20, and 30% reduction of light transmittance). The initial light transmittance of PO film was higher than that of PE film and the decrease in light transmittance of PO film due to PM was less than that of PE film. The vegetative growth of cucumber was promoted under the reduced light transmittance treatments; however, the yield of cucumber was highest in the control (0% reduction of light transmittance). From the results, we confirmed that PO film was less PM adhesion and that cucumber yield during the spring season can be reduced by the reduction in light transmittance due to PM.

• Journal of Biosystems Engineering
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• v.32 no.5
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• pp.332-338
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• 2007

Yield mapping is necessary for precision farming. An on-site rice weighing system for a head-feed combine was developed to measure the total weight of rice grain harvested while the combine was operated. A load cell system was used to monitor rice weights accumulated into the combine grain tank using a load cell. This method gave cumulative grain weight readings as a function of time. The system consisted of a load cell, two supporting brackets, and a computer-based data acquisition system. The weights measured with the system from two fields were compared with those obtained with a commercially available electronic balance. The response of the load cell to varying grain weights was linearly modeled, showing a coefficient of determination of 0.998 and a standard error of ${\pm}4.09kg$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.1
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• pp.60-66
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• 2005

Pod shape of twenty soybean (Glycine max L. Merrill) genotypes was evaluated quantitatively by image analysis using elliptic Fourier descriptors and their principal components. The closed contour of each pod projection was extracted, and 80 elliptic Fourier coefficients were calculated for each contour. The Fourier coefficients were standardized so that they were invariant of size, rotation, shift, and chain code starting point. Then, the principal components on the standardized Fourier coefficients were evaluated. The cumulative contribution at the fifth principal component was higher than $95\%$, indicating that the first, second, third, fourth, and fifth principal components represented the aspect ratio of the pod, the location of the pod centroid, the sharpness of the two pod tips and the roundness of the base in the pod contour, respectively. Analysis of variance revealed significant genotypic differences in these principal components and seed number per pod. As the principal components for pod shape varied continuously, pod shape might be controlled by polygenes. It was concluded that principal component scores based on elliptic Fourier descriptors yield seemed to be useful in quantitative parameters not only for evaluating soybean pod shape in a soybean breeding program but also for describing pod shape for evaluating soybean germplasm.

• Korean Management Science Review
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• v.31 no.3
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• pp.1-12
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• 2014

This study suggests the two types DEA models such as DEA CCR model and Super Efficiency model to evaluate the value of a company and to apply them for the investments. 14 kinds of real data of companies such as EV/EBITDA, EPS growth rate, PCR, PER, dividend yield, PBR, stock price/net current asset, debt ratio, current ratio, ROE, operating margin, inventory turnover, accounts receivable turnover, and sales growth ratio were used as input variables of DEA models. 12 year data from December 30, 2000 up to December 30, 2012 were collected, and the data with negative, missing and 0 values were removed reflecting the characteristics of the DEA. In order to verify the effectiveness of the models, we compared the historical variability and rate of return of both models those of the market. Study results are as follows. First, two DEA models are more stable than market in terms of rate of return because the historical variability of both models are less than that of market. Second, Super Efficiency model is more stable than CCR model. Lastly, the cumulative rate of return of Super Efficiency model (434%) is greater than that of the CCR model (420%) and that of the market (269%).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.796-803
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• 1998

Intrinsic and proximity gettering are popular processes to get higher cumulative production yield and usually adopt multi-step annealing and high energy ion implantation, respectively. In order to test the combined processed of these, high energy \ulcornerAs\ulcorner ion implantation and 2-step annealing process were adopted. After the ion implantation followed by 2-step annealing, the wafers were cleaved and etched with Wright etchant. The morphology of cross section on samples was inspected by FESEM. The concentration profile of As was measured by SRP. The location and type of secondary defects inspected by HRTEM were dependent on the 1st annealing temperatures. That is, a line of dislocation located at $1.5mutextrm{m}$ apart from the surface at $600^{\circ}C$ lst annealing was changed to some dislocation lines or loops nearby the surface at 100$0^{\circ}C$. The density of dislocation line was reduced but the size of the defects was enlarged as the temperature increased.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.3
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• pp.227-234
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• 2016

The influence of mixing on biogas production and organic material removal performance of solid state anaerobic digestion of dairy manure and sawdust bedding mixtures was evaluated using 22 L volume lab-scale digesters. After 45 days of anaerobic digestion at $37^{\circ}C$, cumulative methane yield of unmixed test unit ($73.1N{\cdot}mL/g-VS$) was almost 1.3 times of that of mixed one ($56.3N{\cdot}mL/g-VS$). The biodegradable volatile solids removal rate of unmixed test unit was 67%, which was almost 28% greater than mixed one. Our results reveal that unmixed condition is better than mixed one in terms of biogas production and organic material reduction.

• Korean Journal of Legislative Studies
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• v.23 no.1
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• pp.81-111
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• 2017

This article analyzes three major issues related to regional voting in South Korea. First, is regional voting a regional problem or an ideological problem? Second, is regional voting caused by regional identity or regional interest? Third, has regionalism waxed or waned? Analyses of the cumulative data set since the 15th presidential election yield the following results. First, Yongnam people are more conservative than Honam people. Second, regional voting consists of ideological and regional components. Third, there exist both a hometown effect and an abode effect in regional voting, but the latter is significantly greater than the former. Forth, regionalism had weakened between the 15th National Assembly election and the 16th Presidential election, but has not varied much since then.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.6
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• pp.9-18
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• 2019

This study derives load characteristics and analyzes the safety of plowshares operating in dry fields. We mounted a three-blade, reversible plow on a 23.7 kW tractor and measured the plow's tractive force as well as the torque from the engine output shaft on the rear axle under various working speeds (L4, M1, M2, M3). We chose a Korean test site of Seomyeon, Chuncheon with sandy soil texture, as determined using the USDA method. We constructed the load spectrum for torque and tractive force using measured data and derived the fatigue life of the plowshare from a stress-cycle (S-N) curve of the plow material. Our results show that the M3 gear maximizes the driving shaft torque loads and, applying the tractive force load spectrum, creates a cumulative damage sum of $4.14{\times}10^{-5}$. Considering sampling time, we estimate a fatigue life of 805 hours while using the M3 gear. When using the other working speeds, however, all of the stress levels fell within the endurance limits and, therefore, our model predicts infinite plowshare lifetimes. For this analysis, we used a yield strength of 1,079 MPa for the plowshare and static safety factors, analyzed using the maximum stress, between 6.83 and 8.63 under each working speed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.1
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• pp.73-80
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• 2022

Sensors are applied to small aviation platforms for various purposes. Radio frequency (RF) antennas, which are representative sensors, are available in many forms but require the application of slot array RF antennas to ensure high performance and designation. Slot RF array antennas are applied to dip brazing techniques, but the yield and production time are determined by the proficiency of production personnel in a labor-intensive form. Unmanned aerial vehicles or drones, which are representative small aviation platforms, are continuously exposed to various random vibrations because propellers and multiple power sources are used in them. In this study, the fatigue life of slot array RF antennas applied with additive manufacturing was evaluated through the cumulative damage method (Miner's rule) in a vibration environment with a small aviation platform. For the evaluation, an S N curve obtained from a fatigue strength test was used.