• Animal Bioscience
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• v.36 no.5
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• pp.761-767
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• 2023

Objective: The objective of this study was to determine whether dietary supplementation with a functional fatty acid blend (FA) that contains 31.4% butyric acid and 4.99% medium-chain FA improve growth performance, antioxidant capacity, immunity status, and anti-inflammatory ability in weaned piglets. Methods: One hundred and forty-four healthy piglets (Duroc×Landrace×Yorkshire) with an average body weight (BW) of 7.98±3.43 kg were randomly divided into three groups with six replicate pens and eight piglets per pen: Normal control (NC): a corn-soybean basal diet; FA1: a basal diet supplemented with 1,000 mg/kg of a functional FA; FA2: a basal diet supplemented with 2,000 mg/kg of a functional FA. The experiment lasted for 28 d. On d 14 and 28, one piglet in each pen from NC and FA2 groups was randomly selected for antioxidative index and immunoglobulins. On d 28, one piglet in each pen from NC and FA2 groups was randomly selected for intestinal morphology and inflammatory factor. Results: We observed that FA supplementation linearly increased (p<0.05) average daily gain and the final BW. There was higher (p<0.05) catalase on d 14, and immunoglobulin (Ig) A and IgM on d 28 in piglets supplemented with FA2 than in the NC group. Moreover, dietary FA2 reduced (p<0.05) crypt depth of ileum in piglets. The concentrations of tumor necrosis factor-α, interleukin (IL)-1β, IL-8, and IL-10 in jejunum were lower (p<0.05) in the FA2 group compared with the NC group. Conclusion: Therefore, the overall results suggests that the FA may help to improve gut health, antioxidant status, and immune parameters resulting in the improvement of growth performance.

• Journal of Power Electronics
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• v.14 no.1
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• pp.61-73
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• 2014

Multiphase machines are characterized by high power density, enhanced fault-tolerant capacity, and low torque pulsation. For a voltage source inverter supplied multiphase machine, the probability of load imbalances becomes greater and unwanted low-order stator voltage harmonics occur. This paper deals with the PWM control of multiphase inverters under unbalanced load conditions and it proposes a novel near-five-vector SVPWM algorithm based on the five-phase six-leg inverter. The proposed algorithm can output symmetrical phase voltages under unbalanced load conditions, which is not possible for the conventional SVPWM algorithms based on the five-phase five-leg inverters. The cause of extra harmonics in the phase voltages is analyzed, and an xy coordinate system orthogonal to the ${\alpha}{\beta}z$ coordinate system is introduced to eliminate low-order harmonics in the output phase voltages. Moreover, the digital implementation of the near-five-vector SVPWM algorithm is discussed, and the optimal approach with reduced complexity and low execution time is elaborated. A comparison of the proposed algorithm and other existing PWM algorithms is provided, and the pros and cons of the proposed algorithm are concluded. Simulation and experimental results are also given. It is shown that the proposed algorithm works well under unbalanced load conditions. However, its maximum modulation index is reduced by 5.15% in the linear modulation region, and its algorithm complexity and memory requirement increase. The basic principle in this paper can be easily extended to other inverters with different phase numbers.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.4
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• pp.221-229
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• 2017

In the international businesses human resource elements acquired in different countries might have different values in varied industries due to the different quality of education and experiences in the original countries. Using selection models to evaluate expected values in earnings equation of human resource elements such as education and experiences etc. acquired in sending countries, system equations are expanded to examine also the values of science and engineering degrees in technology jobs with selectivity bias correction. This paper used the US census survey data of 2015 on earnings, academic degrees, occupations etc. The US has long maintained the policy of accepting more STEM workers than any other countries and helped maintaining own technological leadership. Assuming per capita GDP gap between the sending country and the US downgrades immigrant human resource quality, it rarely affects occupational selection but depresses earnings on average by two or more years' worth of education. Immigrant quality index in the sense of GDP gap appears to be a valid tool to assess the expected earnings of the worker with. Engineering degrees increase significantly the probability of selecting not only engineering jobs but also general management jobs, as well as increasing the expected earning additionally over nine years'worth of education. Getting a technology job is additionally worth about four years of education. Economics and business degrees are worth additionally almost six years of education but humanities degrees depress expected earnings. Since years after immigration does not very fast enhance earnings capacity, education level and English language ability might be more useful criteria to expect better future earnings by.

• Food Science of Animal Resources
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• v.43 no.2
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• pp.245-268
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• 2023

The effects of phosphate alternatives on meat quality in marinated chicken were investigated with the application of chilling and freezing. Breast muscles were injected with solution of the green weight containing 1.5% NaCl and 2% sodium tripolyphosphate (STPP) or phosphate alternatives. Treatment variables consisted of no phosphate [control (-)], 0.3% sodium tripolyphosphate [control (+)], 0.3% prune juice (PJ), 0.3% oyster shell, 0.3% nano-oyster shell, and 0.3% yeast and lemon extract (YLE) powder. One-third of the meat samples were stored at 4℃ for 1 d, and the rest of the meats were kept at -18℃ for 7 d. In chilled meat, a lower drip loss was noted for control (+) and YLE, whereas higher cooking yield in YLE compared to all tested groups. Compared with control (+), the other treatments except PJ showed higher pH, water holding capacity, moisture content, lower thawing and cooking loss, and shear force. Natural phosphate alternatives except for PJ, improved the CIE L^* compared to control (-), and upregulated total protein solubility. However, phosphate alternatives showed similar or higher oxidative stability and impedance measurement compared to control (+), and an extensive effect on myofibrillar fragmentation index. A limited effect was observed for C^*, h°, and free amino acids in treated meat. Eventually, the texture profile attributes in cooked of phosphate alternatives improved except for PJ. The results indicate the high potential use of natural additives could be promising and effective methods for replacing synthetic phosphate in chilled and frozen chicken with quality enhancement.

• Korean Journal of Food Science and Technology
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• v.26 no.4
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• pp.348-354
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• 1994

Chitin and chitosan samples prepared from crab's shells under different conditions were compared for their physicochemical properties; and functionality in gastrointestinal tract by in vitro test. Their bulk density was in the range of $127{\sim}208\;mg/ml$, and their viscosity was $80{\sim}581\;cP$ in 0.1 chitin and $80{\sim}3,670\;cP$ in 0.5% chitosan solution, showing a wide variation. The degree of deacetylation in chitosan samples as determined by IR spectral analysis was relatively high, showing $81{\sim}93%$. At the same alkali concentration and reaction temperature, a longer reaction period gave an increased degree of deacetylation and lower viscosity. The water holding capacity of chitic substance became greater at higher soaking temperature; chitosan D at $37^{\circ}C$ showed the greatest value. Chitic substance with lower bulk density showed the higher water holding capacity. The retardation effect toward glucose absorption was higher in critic substances of lower density and higher water holding capacity; chitosan D showed the highest value of 38%. The retardation index toward bile acid absorption after 1 hour dialysis was $15{\sim}34%$ in chitic substances, 39% in pectin and 9% in cellulose. The retarding effect showed the highest value of 34% in chitosan D at 3% concentration.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.2
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• pp.59-71
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• 2022

This study considered regional differences in the university-industry collaboration of Korean universities and performed cluster analysis to identify the spatial range with high university-industry collaboration connectivity. By university establishment type, it was found that the university-industry collaboration capacity of the major national university was superior overall, especially in the technology transfer & commercialization sector and the infrastructure sector, compared to private universities and general national universities. The spatial pattern of university-industry collaboration capacity showed relatively clear differences by city and province. In terms of university-industry collaboration capacity by sector, it was confirmed that the regional gap was not large in the talent training sector and the infrastructure sector, but the regional gap was relatively large in the technology transfer & commercialization sector and the start-up sector. As a result of the cluster analysis to identify a spatial range with high connectivity in terms of similarity and spatial proximity of university-industry collaboration patterns, it is divided into 15 clusters. It is found that most of major national universities are included in one of 15 clusters where all sectors of university-industry collaboration are strong. Therefore, as a policy measure to achieve regional innovative growth through enhancing the effectiveness of university-industry collaboration, we propose the establishment of a hub & spoke network-type collaboration system in which a major national university acts as a hub and nearby local universities play a spoke role.

• Safety and Health at Work
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• v.10 no.4
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• pp.527-530
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• 2019

The increasing prevalence of inactivity and obesity, along with aging, has implications on work capacity of labor force. This study reports the relationships between activity level and BMI by age with objectively measured physical workload. Data were examined from a sample of 19 481 Finnish employees using an estimate of minute-to-minute oxygen consumption based on R-R interval recordings. The mean estimated %VO₂max during the working day was 12.1 (±3.6) and 15.1 (±4.5)% for men and women, respectively. Based on a linear model, the mean %VO₂max increased by 1.5%-unit per 10-year increase in age, by 2.1%-unit per 5 kg/㎡ increase in BMI, and decreased by 1.6%-unit if improving physical activity class by two (p < 0.001 for all). Overweight and obesity, together with inactivity, notably increases workload throughout the career, even though at young adulthood, the daily workload is almost the same for each person regardless of the BMI, activity level, or gender. This study highlights the importance of regular physical activity and normal weight in protecting the worker from excessive physical (cardiovascular) workload during the whole working career.

• Journal of the Korea Concrete Institute
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• v.28 no.2
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• pp.177-185
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• 2016

This paper concerns the flexural behavior of steel fiber-reinforced ultra-high-performance concrete (UHPC) beams with compressive strength of 150 MPa. It presents experimental research results of hybrid steel fiber-reinforced UHPC beams with steel fiber content of 1.5% by volume and steel reinforcement ratio of less than 0.02. This study aims at investigating of compressive and tensile behavior of UHPC to perform a reasonable prediction for flexural capacity of UHPC beams. Tensile behavior modeling was performed using load-crack mouth opening displacement relationship obtained from bending test. The experimental results show that steel fiber-reinforced UHPC is in favor of cracking resistance and ductility of beams. The ductility indices range from 1.6 to 3.0, which means high ductility of hybrid steel fiber-reinforced UHPC. Test results and numerical analysis results for the moment-curvature relationship are compared. Though the numerical analysis results for the bending capacity of the UHPC beam without rebar is larger than test result, the overall comparative results show that the bending capacity of steel fiber-reinforced UHPC beams with compressive strength of 150 MPa can be predicted by using the established method in this paper.

• Journal of the Korean Geotechnical Society
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• v.37 no.9
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• pp.25-36
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• 2021

Recently, the intelligent compaction technology for quality control of earthworks has brought attention as a quality control standard for earthworks. In this study, intelligent compaction technology and earthwork quality control methods were investigated and earthwork quality control procedures using intelligent compaction technology were considered based on field tests. Through the field compaction test of the silty sand (SM) fill material, it was confirmed that CMV and bearing capcaity index from plate load tests increased as the number of compactions increased. Based on the field test data, the average CMV and quality control target CMV were derived. The target CMV (34.2) was calculated through the correlation with the bearing capacity index of the plate load test, and the target CMV (36.6) was calculated through the analysis of the CMV increase rate. In this paper, the on-site compaction quality management procedure and methodology using intelligent compaction technology were discussed, and an intelligent compaction quality management method was proposed to promote the applicability of the technology.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.427-434
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• 2010

Load Resistance Factor Design method is used increasingly in geotechnical design world widely and resistance factors for drilled shafts are suggested by AASHTO. However, these resistance factors are determined for intact rock conditions, by comparison most of bedrocks in Korea are weathered condition, so that applying the AASHTO resistance factors is not reasonable. Thus, this study suggests the proper resistance factors for design of drilled shaft in Korea. The 22 cases of pile load test data from 8 sites were chosen and reliability-based approach is used to analyze the data. Reliability analysis was performed by First Order Second Moment Method (FOSM) applying 4 bearing capacity equations. As a result, when the Factor of Safety(FOS) were selected as 3.0, the target reliability index($\beta_c$) were evaluated about 2.01~2.30. Resistance factors and load factors are determined from optimization based on above results. The resistance factors ranged between 0.48 and 0.56 and load factor for dead load and live load are evaluated approximately 1.25 and 1.75 respectively. However, when the target reliability are considered as 3.0, the resistance factors are evaluated as approximately 50% of results when the target reliability index were 2.0.