• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.3
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• pp.275-280
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• 2016

In this study, a release test bed is designed to evaluate the dynamic behaviors of a coil spring. From the release tests, the dynamic behaviors of a coil spring are analyzed. A lumped parameter spring model was established for numerical simulation of a spring. The design variables of a coil spring are optimized by using the design of experiments approach. Two-level factorial designs are used for the design optimization, and the primary effects of the design variables are analyzed. Based on the results of the interaction analysis and design sensitivity analysis, the level of the design variables is rearranged. Finally, the mixed-level factorial design is used for the optimum design process. According to the optimum design of the opening spring, the dynamic performance of the spring-operated mechanism increases by 2.90.

• Journal of the Korean Institute of Landscape Architecture
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• v.20 no.2
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• pp.127-140
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• 1992

본 연구에서는 Schwartz의 Norm Activation 이론을 도입하여, 실 외휴양지에서 환경훼손행위 관리를 위한 Communicatin 정책의 이론적 배 경으로 도입되어 있는 Prosocial Behavior 이론의 적용성을 실험하였다. 본 연구는 실험실에서 자체개발한 설문지를 통하여 수행되었으며, 미국 Texas A&M 대학교의 남녀 대학생 340명이 참가하였다. 본 실험의 결과 실외휴 양 환경에 대한 훼손행위(Depreciative Behavior)의 인과응보적인 결과를 알려 주는 Information이 실외휴양지 관리에 바람직한 행동의사를 활성화 시키는데 효과적인 반면, 훼손행위에 대한 법적인 제재조치를 설명하는 위 협적 Information은 바람직한 행동의지를 활성화시키지는 못했다. 이용자의 개인적인 성향인자인 사회적 책임감(Social Responsibility)의 고저는 사회 에 바람직한 행동의지의 활성화와 직접적인 관계가 있었다. 그러나, 사회적 책임감의 고저가 환경훼손행위에 대한 인과응보적인 Information이나 제재 조치에 대한 위협적인 Information과의 교호작용은 없었다. 통계학적으로 유의성은 적으나 사회적 책임감이 높은 시험구의 경우 제재조치에 대한 위 협적인 Information에 대한 반작용이 컸으나, 사회적인 책임감이 높은 실험 구의 경우 제재조치에 대한 위협적인 Information이 효과적인 결과를 볼 때, 이용자의 바람직한 행동의지에 역으로 작용하는 Communication정책에 대한 체계적인 연구가 요구된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.529-533
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• 2012

본 연구에서는 실내실험을 통하여, 하안침식을 고려한 망상하천에서 저수로의 이동특성을 조사하며, 2중 퓨리에 해석에 의하여 사주의 거동특성을 분석하였다. 실내실험은 평균입경이 1.4 mm이고, 표준편차가 1.35인 균일사로 10 cm 의 두께로 전체가 균등하게 채워진, 길이가 12 m, 넓이 2 m 수로에서 수행하였다. 각 시간별 하도의 지형변화에 대하여 2 중 Fourier 해석에 의한 지배적인 성분, 즉 모드(mode)의 변화를 분석하였다. 여기서 1-1 mode는 교호사주(alternate bars)이고, 1-2 mode와 2-2 mode는 2차 횡방향 모드로서 중앙 사주(central bars)를 나타낸다. 1-3 mode와 2-3 mode는 한 단면에서 횡방향으로 3개의 사주가 형성된 것(triple row bars)를 나타낸다. 초기에는 1-1 mode인 교호사주가 지배적이지만, 시간이 증가함에 따라, 교호사주인 1-1 mode는 감소하고, 한 단면에서 3개의 사주가 형성되는 2-3 mode가 지배적인 것으로 나타났다. 이러한 원인은 시간이 지나면서 사주가 발달하고, 하안침식이 되면서, 하폭이 증가하여 상대적으로 수심이 감소하면서 복렬사주가 발달하기 때문이며, Colombini 등(1987)이 이론적으로 예측한 결과와 잘 일치한다. 한 단면에서 3개의 모드가 나타나는 것은 하상에서 변화를 일으키는데 중요한 역할을 한다. 직선하도에서 사주의 수가 증가하는 것은 교호사주의 강한 비선형으로 상호작용하기 때문이다.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.3
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• pp.233-240
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• 1999

Understanding of the relationships between seeding rate and planting date is important for production of spring oats during the fall season. Therefore, this experiment was conducted to investigate seeding rate and planting date effects on forage performance and quality of spring oats(Avena sativa L.) at Suweon in 1997. The experiment was arranged in a split plot design with three replications. The main plots consisted of different seeding rates such as 150, 200, and 250kg/ha. The subplots consisted of different planting dates of spring oats such as 15, 22, and 29 August and 5 September. Dry matter content of oats was significantly decreased(P<0.01) as the planting date was delayed except the planting date of 5 September(24.8%). Dry matter content of forage oats planted on 15, 22, and 29 August was 23.0, 21.5, and 20.5%, respectively. A seeding $rate\;{\times}\;planting$ date interaction for dry matter content was highly significant(P<0.01). Crude protein content of oats was significantly increased(P<0.01) from 15.6 to 27.9% as the planting was delayed, while a significant seeding $rate\;{\times}\;planting$ date interaction for crude protein content of oats was observed. Acid detergent fiber(ADF) and neutral detergent fiber(NDF) contents of oats increased with early planting(P<0.01), but there was no significant difference among the seeding rates. ln vitro dry matter digestibility(IVDMD) of oats was significantly increased(P<0.01) as the seeding rate was increased together with late planting. Average dry matter yield of oats decreased(P<0.01) from 2,647 to 615kg/ha as the planting was delayed, but there was no significant difference among the seeding rates. A seeding $rate\;{\times}\;planting$ date interaction was observed for average dry matter yield of oats that the seeding rate increase in this experiment showed better at early planting dates. Crude protein yield of oats increased from 171 to 410kg/ha as the planting was delayed, and a significant increases(P<0.01) for crude protein yield was found among the seeding rates. ln vitro digestible dry matter(IVDDM) yield of oats decreased(P<0.01) as the planting was delayed, but there was no significant difference among the seeding rates. A significant seeding $rate\;{\times}\;planting$ date interaction for lVDDM of oats was found. The results of this study indicate that both the seeding rate of 200kg/ha and early planting before 29 August would be recommendable for forage yield and quality of oats in Korea.

• Horticultural Science & Technology
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• v.28 no.3
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• pp.335-342
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• 2010

Sulforaphane (SFN) and total phenolics (TPC) contents and antioxidant activity (AA) were analyzed from 13 radish genotypes (Rhaphanus sativus L.), cultivated at 3 locations with different altitudes (Gangneung: asl 5 m, Jinbu: asl 550 m, and Daegwallyeong: asl 750 m). SFN varied greatly from 0.1 to $120.5{\mu}g{\cdot}g^{-1}$ in dry weight test and was significantly affected by location ($P{\leq}0.001$), genotype ($P{\leq}0.001$) and $location{\times}genotype$ interaction ($P{\leq}0.01$). Radishes, cultivated at Daegwallyeong site, showed higher SFN than those of other locations. Among different genotypes, the root of 'Black radish' and leaves of 'Purunmu' of Daegwallyeong had the highest SFN (107.8 and $120.5{\mu}g{\cdot}g^{-1}$, respectively). TPC in root was affected by genotype ($P{\leq}0.001$), and $location{\times}genotype$ interaction ($P{\leq}0.01$), but not by location. In leaves, TPC was affected by location ($P{\leq}0.01$), genotype ($P{\leq}0.001$), and $location{\times}genotype$ interaction ($P{\leq}0.001$). AA expressed as electron donating ability was significantly influenced by location, genotype and $location{\times}genotype$ interaction and correlated positively with TPC ($Pearson's$ $r$=0.897) in root. These results suggest that radish could be a good source of functional food and high altitude location such as Daegwallyeong has potential for the production of radish with high content of health promoting factors.

• Journal of Korean Society for Quality Management
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• v.45 no.1
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• pp.55-64
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• 2017

Purpose: A large number of attributes with mixed levels are often considered in the conjoint analysis. The respondents may have difficulty with scoring their preferences accurately because of many attribute items involved in each survey question. We research on the technique for reducing the number of attribute items. Methods: In order to reduce the number of attribute items in a survey question, we make a new attribute by merging two original attributes. A 'No question' option is also included as a new level in a merged attribute. Results: We propose BIB $6^4$ design in the case where we have four attributes with 2 levels and 3 levels, respectively and then analyze all the respondents survey data generated by the repeated simulation study in order to compare various model selection methods. Conclusion: How to reduce the number of attribute items is proposed and how to design and analyze the survey data are illustrated.

• Environmental and Resource Economics Review
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• v.27 no.3
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• pp.421-461
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• 2018

Windpower turbines have positive values for visitors with regard to tourism and learning. On the other hand, it is clear that windpower turbines have negative impact on the landscape, particularly when the level of landscape is high. The impact of windpower turbines on the visitor's value is composed of two elements: the viewingvalue which is independent of the level of landscape and the landscape value which varies with the level of landscape. The net visitor's value of windpower turbines is the sum of these two values with opposite signs. This study used a choice experimentation method to value the impact of windpower turbine construction in the mountainous area in Korea. This study estimated the viewing value, the landscape value and the visit value as the sum of the two values. The estimated results demonstrated a significantly positive viewing value, a significantly negative landscape value, and weakly negative net visit value in average.

• Journal of Korea Water Resources Association
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• v.47 no.1
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• pp.37-47
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• 2014

This study examines the processes and the behaviour characteristics of forcing bars in channels with periodic variable width in the alternate and braided regimes by using a two dimensional numerical model. The wavelength and the migration speed decrease as the amplitude of variable width increases. The forcing effects of the width variation on the alternate bars is stronger than those on the braided bars. The bar migration speed increases as the dimensionless amplitude in the braided regime is 0.25. However, the migration speed is abruptly decreased as the amplitude in it was larger than 0.25. The bar migration speed increases in the alternates bar regime as the dimensionless wavelength increases. However, the migration speed decreases around 1 of the wavelength. As the bar wavelength and the variable width wavelength coincide, the bars don't migrate downstream by the strong forcing effects on the bars due to the suppression by the width variation.

• Korean journal of applied entomology
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• v.48 no.2
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• pp.123-158
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• 2009

An attempt was made to stimulate future research by providing exemplary information, which would integrate published knowledge to solve specific pest problem caused by resistance. This review was directed to find a way for delaying resistance development with consideration of chemical(s) nature, of mixture, rotation, or mosaics, and of insecticide(s) compatible with the biological agents in integrated pest management (IPM). The application frequency, related to the resistance development, was influenced by insecticide activity from potentiation, residual period, and the vulnerability to resistance development of chemical, with secondary pest. Chemical affected feeding, locomotion, flight, mating, and predator avoidance. Insecticides with negative cross-resistance by the difference of target sites and mode of action would be adapted to mixture, rotation and mosaic. Mixtures for delaying resistance depend on each component killing very high percentage of the insects, considering allele dominance, cross-resistance, and immigration and fitness disadvantage. Potential disadvantages associated with mixtures include disruption of biological control, resistance in secondary pests, selecting very resistant population, and extending cross-resistance range. The rotation would use insecticides in high and low doses, or with different metabolic mechanisms. Mosaic apply insecticides to the different sectors of a grid for highly mobile insects, spray unrelated insecticides to sedentary aphids in different areas, or mix plots of insecticide-treated and untreated rows. On the evolution of pest resistance, selectivity and resistance of parasitoids and predator decreased the number of generations in which pesticide treatment is required and they could be complementary to refuges from pesticides To enhance the viability of parasitoids, the terms on the insecticides selectivity and factors affecting to the selectivity in field were examined. For establishment of resistant parasitoid, migration, survivorship, refuge, alternative pesticides were considered. To use parasitoids under the pressure of pesticides, resistant or tolerant parasitoids were tested, collected, and/or selected. A parasitoid parasitized more successfully in the susceptible host than the resistant. Factors affecting to selective toxicity of predator are mixing mineral oil, application method, insecticide contaminated prey, trait of individual insecticide, sub-lethal doses, and the developmental stage of predators. To improve the predator/prey ratio in field, application time, method, and formulation of pesticide, reducing dose rate, using mulches and weeds, multicropping and managing of surroundings are suggested. Plant resistance, predator activity, selective insect growth regulator, and alternative prey positively contributed to the increase of the ratio. Using selective insecticides or insecticide resistant predator controlled its phytophagous prey mites, kept them below an economic level, increased yield, and reduced the spray number and fruits damaged.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.117-117
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• 2003

다시마(Laminaria japonica) 생태육종 연구의 일환으로 완도산과 백령도산 품종의 재배시험을 전남 고흥군 명천어장과 계도어장에서 2001년부터 2002년까지 실시하였다. 시험기간 중 어장의 수온, 염분농도, 유속, 용존산소농도는 구간별로 유의차가 없었으며 수온은 1월부터 7월까지 점차 상승하였고, 염분농도는 5월까지 상승하다가 6월과 7월에 낮아졌다. 유속은 저층에서보다 표층에서 빨랐고, 용존산소농도는 1월부터 7월까지 점차적으로 낮아졌다. 어장의 영양염 변화는 구간별로 1월부터 7월까지 유의차가 없었으며 암모니아염이 5월에 다소 증가하였다. 일반적으로 전장과 엽폭은 4월까지 증가하다가 끝녹음으로 인하여 4월이후에는 다소 감소하였으나, 엽두께, 전중량, 비대도는 7월까지 계속적으로 증가하였다. 형질간의 상관관계는 모두 1%와 5% 수준에서 유의차가 있었다. 각형질에 있어서 품종과 환경간에 월별로 질적교호작용과 양적교호작용중 어느 한 쪽이 나타났다. 품종시험에 의한 유전력은 엽폭에서 가장 높았고, 엽두께에서 가장 낮았다. 표현형상관, 유전상관, 환경상관계수는 형질간에 대부분 높은 값을 보였으나 엽두께와 전중량간의 값이 일반적으로 낮았다. 부모와 자식간의 회귀에 의한 유전력은 계도어장의 엽두께에서 가장 높았으나 일반적으로 전중량에서 높았고, 육종가와 유전상관은 전중량에서 가장 높았다. 각 형질의 상대적 경제 가치를 고려한 선발 총점은 명천어장에서의 완도산 품종에서 가장 높았다.