• Journal of Animal Science and Technology
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• v.52 no.1
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• pp.29-36
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• 2010

This experiment was conducted to evaluate the influence of phase feeding methods on growth performance, carcass characteristics, pork quality, and economical efficiency in growing-finishing pigs. A total of 120 crossbred pigs ([Yorkshire ${\times}$ Landrace] ${\times}$ Duroc), average initial body weight 25.23 ${\pm}$ 2.66 kg, were allotted to 5 treatments by body weight and sex in a randomized complete block (RCB) design. Each treatment had 6 replicates with 4 pigs per pen. The treatments were 1) A (fed late weaner feed during whole phase), 2) B (fed late weaner feed in growing phase and grower feed in finishing phase), 3) C (fed grower feed during whole phase), 4) D (fed grower feed in growing phase and early finisher feed in early and late finishing phase), 5) E (fed grower feed in growing phase, early finisher feed in early finishing phase and late finisher feed in late finishing phase). Commercial diets bought from private feed company were used for this experiment. During the early growing phase (6 wks), treatments A and B showed higher growth performance than that of other treatments (P<0.05). However, growth performance tended to be similar among treatments at 10 wks after feeding and there was no difference in time of market weight (13 wks). Moreover, blood urea nitrogen (BUN) concentration was lowered in treatment E than other treatments during whole experimental period (P<0.01). Carcass characteristics and pork quality were measured when body weight of pigs reached at 110.33 ${\pm}$ 2.1 kg. Days to market weight (110 kg), quality grade, pork color, and pork pH did not show any significant difference among treatments. These results suggested that phase feeding based upon growth stages of pigs showed no detrimental effects on growth performance and the pork quality. Moreover, feed cost was saved approximately 37% by phase feeding method without delaying of days to market weight compared to general conventional feeding method (B) of swine farm in Korea.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.7
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• pp.935-945
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• 2009

This study was performed to find the optimum ratio of ingredients in the Chinese quince jam. The experiment was designed according to the D-optimal design of mixture design, which included 14 experimental points with 4 replicates for three independent variables (Chinese quince paste $45{\sim}60%$, pectin $1.5{\sim}4.5%$, sugar $45.5{\sim}63.5%$). A mathematical analytical tool was employed for the optimization of typical ingredients. The canonical form and trace plot showed the influence of each ingredient in the mixture against final product. By use of F-test, sweetness, pH, L, b, ${\Delta}E$, and firmness were expressed by a linear model, while the spreadmeter value, a, and sensory characteristics (appearance, color, smell, taste, and overall acceptability) were by a quadratic model. The optimum formulations by numerical and graphical method were similar: Chinese quince paste 54.48%, pectin 2.45%, and sugar 53.07%. Optimum ingredient formulation is expected to improve use of Chinese quince and contribute to commercialization of high quality Chinese quince jam.

• Horticultural Science & Technology
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• v.29 no.5
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• pp.420-432
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• 2011

Population dynamics of greenhouse whitefly, Trialeurodes vaporariorum (Westwood), were modeled and simulated to compare the temperature effects of air and tomato leaf inside greenhouse using DYMEX model simulator (pre-programed module based simulation program developed by CSIRO, Australia). The DYMEX model simulator consisted of temperature dependent development and oviposition modules. The normalized cumulative frequency distributions of the developmental period for immature and oviposition frequency rate and survival rate for adult of greenhouse whitefly were fitted to two-parameter Weibull function. Leaf temperature on reversed side of cherry tomato leafs (Lycopersicon esculentum cv. Koko) was monitored according to three tomato plant positions (top, > 1.6 m above the ground level; middle, 0.9 - 1.2 m; bottom, 0.3 - 0.5 m) using an infrared temperature gun. Air temperature was monitored at same three positions using a Hobo self-contained temperature logger. The leaf temperatures from three plant positions were described as a function of the air temperatures with 3-parameter exponential and sigmoidal models. Data sets of observed air temperature and predicted leaf temperatures were prepared, and incorporated into the DYMEX simulator to compare the effects of air and leaf temperature on population dynamics of greenhouse whitefly. The number of greenhouse whitefly immatures was counted by visual inspection in three tomato plant positions to verify the performance of DYMEX simulation in cherry tomato greenhouse where air and leaf temperatures were monitored. The egg stage of greenhouse whitefly was not counted due to its small size. A significant positive correlation between the observed and the predicted numbers of immature and adults were found when the leaf temperatures were incorporated into DYMEX simulation, but no significant correlation was observed with the air temperatures. This study demonstrated that the population dynamics of greenhouse whitefly was affected greatly by the leaf temperatures, rather than air temperatures, and thus the leaf surface temperature should be considered for management of greenhouse whitefly in cherry tomato grown in greenhouses.

• Journal of Bio-Environment Control
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• v.25 no.2
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• pp.111-117
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• 2016

The objective of this study was to analyze the microclimate and the growth of tomato and lettuce in the greenhouses covered with spectrum conversion films using different phosphor particles sizes. Two spectrum conversion films using phosphor particles larger than $10{\mu}m$ (Micro-film) and smaller than 500 nm (Nano-film) in radius, and poly-ethylene (PE) film were used in double-layered greenhouses as outer coverings. PE films were used as inner coverings in all the greenhouses. Thickness of the films for inner and outer coverings was 0.06 mm. Tensile strength, elongation, and tearing resistance of the Micro- and Nano-films were not different from those of the PE film. Transmittances at a wavelength of 300-1100 nm were a little higher at the Micro-film and lower at the Nano-film than that of the PE film, respectively. Air temperatures at the Micro- and Nano-films were over $2^{\circ}C$ higher than at the PE film, but no significant difference was observed between the two light conversion films. The soil temperature at the Nano-film was $1.5^{\circ}C$ and $3^{\circ}C$ higher than at the Micro- and PE films, respectively. The yields of tomato at the Micro- and Nano-films were 12% and 14% higher than at the PE film, but no significant difference was observed between the two spectrum conversion films. The total soluble solid showed no significant differences among all the films. The yields of lettuces at the Micro- and Nano-films were 27% and 59% higher than at the PE film. Hunter's red (a) value of the lettuce leaf was the highest at the Nano-film. In this experiment, tomatoes requiring high irradiation were better at the Nano film, while lettuce requiring low irradiation better at the Micro film.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.530-534
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• 2006

조류발전은 조류 유속이 빠른 곳에 수차발전기를 설치하여 해수의 운동에너지로부터 전기를 생산하는 발전방식이다. 2001년부터 해양연구원에서는 울돌목의 우수한 조류발전 개발 여건을 바탕으로 조류에너지 실용화 기술을 개발하고 있다. 본 연구에서는 조류발전 시스템에 사용되는 헬리컬 수차의 효율을 현장실험을 바탕으로 판단하고자 하였다. 현장실험을 위하여 지름 2.2 m, 높이 2.5 m의 수차를 제작하고, 울돌목 협수로의 한 쪽 면에 쟈켓구조물을 설치하여 수차를 거치한다. 수차가 회전함에 따라 회전봉에 일정 마찰을 주어 토크와 RPM을 측정하고, 함께 측정된 유속자료를 이용하여 수차를 효율을 산정한다. 유속-수차효율, TSR(수차의 날개속도와 유속의 비)-수차효율의 상관관계로 실험결과를 고찰하였다. 1중 날개 수차인 경우에 유속 1.4에서 2.6 m/s 사이에서 최대효율이 30 - 35 % 정도였고, 2중 날개 수차에 대한 실험에서는 유속 1.4에서 2.6 m/s 사이에서 최대수차효율이 25 - 35 % 사이임을 알 수 있었다. TSR과 최대수차효율의 상관관계는 실험 case별로 조금씩 다르다. 전체적으로 1중 날개의 경우가 최대수차효율에서 2중 날개보다 TSR 값이 조금 큰 경향을 나타냄을 알 수 있다. 이것은 1중 날개가 2중 날개보다 가벼워 좀 더 큰 RPM을 발생시켜서 나타난 현상으로 생각된다. 현재의 실험결과들을 이용하여 TSR과 최대수차효율을 상관관계를 나타내는 모델식을 도출하였다. 현장시험결과를 종합하면, 현장조류발전 시설이 최소 600 kW의 전력이 생산되기 위해서는 지름 3 m, 높이 3.6 m 인 수차 3개가 하나의 축에 설치되어야하는 것으로 계산되었다. 정격유속이 4.8 m/s이고 수차의 지름이 3m 라면, 최적 전력발생시의 RPM은 1중 날개의 경우 79이고 2중 날개의 경우는 63정도임을 추정할 수 있었다.촬영하여 실시간으로 전송하기 때문에 홍수시 하천 상황에 대한 모니터링 목적으로 사용될 수 있다. 영상수위계는 우물통 등을 이용하는 기존 방법과 비교하여 구조물이 필요 없어 설치 비용이 저렴하고, 영상에 의한 하천 모니터링 기능을 자체적으로 가지고 있기 때문에 효율적이라고 할 수 있다.따른 4개의 평가기준과 26개의 평가속성으로 이루어진 2단계 기술가치평가 모형을 구축하였으며 2개의 개별기술에 대한 시범적용을 실행하였다.하는 것으로 추정되었다.면으로의 월류량을 산정하고 유입된 지표유량에 대해서 배수시스템에서의 흐름해석을 수행하였다. 그리고, 침수해석을 위해서는 2차원 침수해석을 위한 DEM기반 침수해석모형을 개발하였고, 건물의 영향을 고려할 수 있도록 구성하였다. 본 연구결과 지표류 유출 해석의 물리적 특성을 잘 반영하며, 도시지역의 복잡한 배수시스템 해석모형과 지표범람 모형을 통합한 모형 개발로 인해 더욱 정교한 도시지역에서의 홍수 범람 해석을 실시할 수 있을 것으로 판단된다. 본 모형의 개발로 침수상황의 시간별 진행과정을 분석함으로써 도시홍수에 대한 침수위험 지점 파악 및 주민대피지도 구축 등에 활용될 수 있을 것으로 판단된다. 있을 것으로 판단되었다.4일간의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는 경우 주식투자기간은 24개월이하의 중단기가 적합함을 발견하였다. 이상의 행태적 측면과 투자성과측면의 실증결과를 통하여 한국주식시장에 있어서 시장수익률을 평균적으로 초과할 수 있는 거래전략은 존재하므로 이러한 전략을 개발 및 활용할 수 있으며, 특히, 한국주식시장에 적합한 거래전략은 반전거래전

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.430-438
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• 2018

This study was conducted to develop and evaluate a web-based infection prevention education program for children, parents and teachers. Research for development of the web-based education program was completed in four phases (analysis, design, development, and evaluation) from 1 February 2015 to 5 October 2015, and the completed website was named CHILD4HEALTH (http://uwcms.pusan.ac.kr). Educational contents pertaining to infection prevention were composed of three sections, children, parents and teachers. Subjects were divided into nine categories, animation, children's dictionary, with mom, music, games, quizzes, educational contents for parents, educational contents for teachers, school newsletters, and handouts. Six characters were developed to increase interest and educational effect. Program evaluation items comprised the website, reliability, and satisfaction. Website evaluation by parents revealed that ease of use was $3.77{\pm}0.70$, entertainment value was $4.07{\pm}0.27$, childproof was $3.82{\pm}0.67$, education value was $4.02{\pm}0.75$, and design features were rated $3.65{\pm}0.53$. According to teachers, ease of use was $3.98{\pm}0.37$, entertainment value was $4.00{\pm}0.17$, childproof was $4.34{\pm}0.60$, education value was $4.00{\pm}0.20$, and design features were $3.81{\pm}0.56$. Parents scored reliability and satisfaction as $8.33{\pm}0.62$ and $7.80{\pm}0.77$, respectively, while they were scored as $8.50{\pm}0.73$ and $8.10{\pm}0.74$ by teachers. Based on the results of this study, the developed web-based education program will help prevent infectious disease and facilitate development of future education programs regarding such diseases.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.8 no.4
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• pp.145-159
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• 2013

The purpose of this study is to analyze the structural relationship as to how learning flow and self-directed learning are linked to learning motives and academic self-efficacy in the learning setting of high school students. To accomplish such purpose, based on theoretical backgrounds and preceding research findings evaluation models were put to verification for a valid research model for this study. The initial hypothetical model was that self-directed learning ability would have a direct influence on learning motive, academic efficacy and learning flow, while having an indirect influence on learning flow with learning motive and self-efficacy acting as a mediating variable. But the hypothetical model showed low significance level between self-directed learning and learning motive, and learning motive and learning flow. Therefore, links were adjusted to create the final model within the scope that the adequacy of the model might not be compromised. To verify the model, 900 high school students in Seoul were surveyed and the collected data were statistically analyzed using AMOS v21.0 and SPSS v21.0 But 815 surveys were excluded because they were not sufficiently answered. From the analysis, it was found that self-directed learning and academic efficacy have a direct influence on learning flow while self-directed learning and academic efficacy have an indirect leaning motive and learning flow. This finding means that, in the relationship of self-directed learning and learning flow, learning motive and learning efficacy are positive factors that help high school students experience learning flow. Thus, in order to enhance the experience of self-directed learning ability of high school students, various educational endeavors are needed to draw the experience of learning flow during the regular course of study. In addition, customized educational methods and environments are required to increase academic efficacy of the students.

• Progress in Medical Physics
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• v.23 no.3
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• pp.177-187
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• 2012

Magnetic resonance angiography (MRA) techniques are widely used in diagnosis of vascular disorders such as hemadostenosis and aneurism. Especially, phase contrast (PC) MRA technique, which is a typical non contrast-enhanced MRA technique, provides not only the anatomy of blood vessels but also flow velocity. In this study, we developed the 2- and 3-dimensional PC MRA pulse sequences for a low magnetic field MRI system. Vessel images were acquired using 2D and 3D PC MRA and the velocities of the blood flow were measured in the superior sagittal sinus, straight sinus and the confluence of the two. The 2D PC MRA provided the good quality of vascular images for large vessels but the poor quality for small ones. Although 3D PC MRA gave more improved visualization of small vessels than 2D PC MRA, the image quality was not enough to be used for diagnosis of the small vessels due to the low SNR and field homogeneity of the low field MRI system. The measured blood velocities were $25.46{\pm}0.73cm/sec$, $24.02{\pm}0.34cm/sec$ and $26.15{\pm}1.50cm/sec$ in the superior sagittal sinus, straight sinus and the confluence of the two, respectively, which showed good agreement with the previous experimental values. Thus, the developed PC MRA technique for low field MRI system is expected to provide the useful velocity information to diagnose the large brain vessels.

• Journal of Chest Surgery
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• v.29 no.4
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• pp.373-380
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• 1996

Prevention of thromboembolism is the most important task in the development of bioconpatible small caliber artificial vascular graft. In normal vessels, vascular endothelial cells maintain homeosatsis by secreting numerous factors. The aim of this study is to develope a method which Improves biocompatibility of small caliver polyurethane graft using endothelial cell culture technique, and ev luate the efTectiveness of extracelluar matrix for endothelization which was produced by cultured fibroblast. Methods ; Multiporous polyurethane tube of 3 mm diameter, 0.3 mm thickness was manufactured for vascular graft. Three mongrel dogs were intubated and internal jugular veins removed. Extracelluar matrix produced by cultured flbrobast which was obtained from dog's internal jugular vein were coated to the polyurethane graft. Then, endothelial cells extracted from Jugular vein were cultured and fixed on the extracelluar matrix layer of vascular graft. Endothelial cell coated vascular grafts were implanted to the carotid arteries of experimental dogs as interposed autograft. Implanted grafts were removed after 3 and 6 weeks. As a control, PTFE graft was interposed on carotid artery. These experiments demonstrated that extracelluar matrix produced by fibroblast can afford a base for endothelial cell linings of polyurethane graft. Although thrombosis were developed on autografted en othelial cell coated graft, 33% opening was noticed, and showed less adhesion to adjacent tissue layer. These findings suggest that fiboblast produced extracelluar matrix which can be used for edothelial cell lining vascular graft, and by improving the cultured endothelial cell function, there will be a new modality for reducing thrombosis on small vascular graft.

• Journal of The Korean Society of Grassland and Forage Science
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• v.26 no.2
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• pp.113-120
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• 2006

This study was conducted to select the optimum seed mixture for beef cattle (Hanwoo) grazing in middle mountain area at 450m from sea level during 2 years from October 1, 1999. Seed mixtures were composed of four different treatment according to main species such as orchardgrass (T1), perennial ryegrass (T2), timothy (T3) and Italian ryegrass (T4). Grass composition rate of different seed mixtures was decreased mostly at first year of grazing, like 44.9% of orchardgrass in T1 plot, 27.6% of perennial ryegrass in T2 plot, 40.9% of timothy in T3 plot and 40.7% of Italian ryegrass in T4 plot, respectively. Main species in seed mixture were decreased in grazing pasture, but kentucky bluegrass and tall fescue were increased in all plots. Italian ryegrass in T4 plot was well grown in early grown stage and inhibited the growth of other grass species, and 44.2% of Italian ryegrass was maintained in second year in the grazing plot. Average dry matter yields of first you showed 6,673 kg/ha and second year was 10,177 kg/ha. Average TDN yields of different seed mixtures were 6,399 kg/ha in T1, 7,769 kg/ha in T2, 4,383 kg/ha in T3 and 7,146 kg/ha in T4 plot. Average herbage dry matter intakes by different seed mixtures during 2 years were 5,937 kg/ha in T1, 6,375 kg/ha in T2, 4,925 kg/ha in T3 and 6,456 kg/ha in T4. This result indicated that perennial ryegrass would recommended in main species of Hanwoo grazing pasture.