• 전기학회논문지
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• 제59권6호
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• pp.1053-1058
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• 2010

A large modern wind farm should satisfy the requirements for a grid and accomplish the optimization of the wind farm system. The wind farm intertie protection system should consider a Fault Ride-Through (FRT) requirement for more reliable protection. The wind farm should keep connected to the grid in the case of a grid fault whilst it should be isolated for an intertie fault. This paper proposes a distance relaying algorithm suitable for wind farm intertie protection considering the FRT requirement. The proposed algorithm estimates the impedance based on a differential equation method because the frequency of the voltage and current deviates the nominal frequency. The algorithm extends the reach of Zone 1 up to 100 % of the length of the intertie to implement the FRT requirement. To discriminate an intertie fault from a grid fault, the algorithm uses a voltage blocking scheme because the magnitude of the voltage at the relaying point for an intertie fault becomes less than that for a grid fault. The performance of the algorithm is verified using a PSCAD/EMTDC simulator under various fault conditions. The algorithm can discriminate successfully the intertie fault from grid fault and thus helps to implement the FRT requirement of a wind farm.

• 기술혁신학회지
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• 제14권4호
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• pp.983-999
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• 2011

본 논문에서는 기술융합화에 따른 경기도 농업분야의 블루오션 전략으로 경기도 식물공장(vertical farm) 추진의 전략방향을 고찰하고, 이를 위한 과학기술 유관기관간 협력방안을 모색하여 본다. 기술 융복합 성격이 매우 강한 사업의 추진은 사업추진 초기부터 협력을 위한 전략 프레임을 설정하고 이에 따라 협력체계를 구축하는 것이 성공의 열쇠가 될 수 있다. 본 논문에서는 경기도 식물공장의 추진의 미래상을 시나리오플래닝을 통하여 고찰하여 보고, 이의 달성을 위한 향후 식물공장 추진 방향을 고찰한다. 농업기술 융복합 혁신의 산물인 식물공장 추진의 전략방향을 시나리오플래닝을 통하여 다차원적으로 고찰한 본 논문은 융복합 기술관련 연구 조직에게 큰 함의를 제공할 수 있을 것으로 기대한다.

• KIEE International Transactions on Power Engineering
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• 제3A권4호
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• pp.198-205
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• 2003

This paper proposes the adaptive relaying of protective devices applied in the neighboring distribution feeders for reliable and efficient operations of a wind farm interconnected with distribution networks by dedicated lines. A wind farm connected to an electric power network is one of the greatest alternative energy sources. However, the wind turbine generators are influenced by abnormal grid conditions such as disturbances occurring in the neighboring distribution feeders as well as the dedicated power. Particularly, in cases of a fault happening in the neighboring distribution feeders, a wind farm might be accelerated until protective devices clear the fault. Therefore, the delayed operation time of protective devices for satisfying the coordination might overly expose the interconnected wind turbine generators to the fault and cause damage to them. This paper describes the proper delayed operation time of protective relay satisfying the coordination of the distribution networks as well as reducing damage on the interconnected wind farm. The simulation results for the Hoenggye substation model composed of five feeders and one dedicated line using PSCAD/EMTDC showed that the proper delayed time of protective devices reflecting the fault condition and the power output of the wind farm could improve the operational reliability, efficiency, and stability of the wind farm.

• 한국지역사회생활과학회지
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• 제14권2호
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• pp.15-27
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• 2003

This study investigates the reports about financial management and financial information needs in farm household, to development financial education program for farm household. The results were as follows: 1) Financial management was carried of husband (49%), husband and wife (31.0%) and wife (15.2%) 2) Farm households demand of financial information was selling for farm products(66.5%), farm management(65.1), keeping budget(52.6%) and consumer information(42.6%). 3) The variables (sex, age, Education, farming type) have statistically significant on test of financial knowledge. 4) On the basis of results, for the stabilization of rural economy it is necessary to maximize and stabilize the rural house hold income however, it is also necessary to educate the rural people by providing the ways and means to efficiently manage the income. Thus various financial management programs and educational resources should be developed and provided to the agriculture household finance managers and the instructors in Agricultural Technology Development Center. Specially, according to the financial knowledge test as the demand of financial information in the group of respondents who answered ‘don’t know’ is higher than the demand in the group of right or wrong answers it is quite urgent to develop and provide the financial education programs and financial resources for these people.

• Asian-Australasian Journal of Animal Sciences
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• 제10권6호
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• pp.621-628
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• 1997

This study aimed to quantify the impact of crossbreeding at farm level, in mixed farm systems in Gujarat. Households with crossbred cattle did not differ from households without crossbreds in terms of farm resources, crop gross margins and off-farm income. The use of crossbred animals did increase livestock gross margins by 64% and household income by 22%. The three agro-ecological zones included in this study differed considerably according to farm system and household income. However, in all three zones, households with crossbreds had higher livestock gross margins than households without crossbreds. There was no real difference in work load and labour division between households with and without crossbreds. There was also no difference in the use of bullocks for draught purposes between the two types of households. In particular buffaloes are being replaced by crossbred cattle. There was a large variation in farm income, largely because of land area. The milk offake per average cow and the number of buffaloes also related positively to farm income in both types of households. Crossbreeding has proved technically and financially viable in different Gujarat mixed farming systems. It can be concluded that crossbreeding is an important development option for landless farmers.

• 한국공간구조학회논문집
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• 제13권2호
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• pp.93-99
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• 2013

Korea has been striving for the development of the nation in various aspects. It will also have to make an effort for its continued development in the future. The problems of low-income groups that occur in those processes cannot be simply ignored now. It is needed to provide an equal opportunity to low-income groups so that they can be part of the society. The cycle of economic problem should be disconnected through this process. Farm-Housing is one of the solutions to this problem. Its purposes are not only to provide residence in the complex, but to gain income through various activities, such as production, distribution and consumption, and solve part of the economic problems of the people living in the Farm-Housing. To sell the products of Farm-Housing, the neighboring cities need to be designated as a hinterland. For this reason, Farm-Housing needs to be located in the suburban area of large cities. However, the current laws and policies make it difficult to construct Farm-Housing in suburban areas. Presenting plans to solve such problem is the purpose of this paper.

• 한국태양에너지학회 논문집
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• 제35권3호
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• pp.17-25
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• 2015

The main objective of this study is to predict the wind power generation at the wind farm using various wake models. Modeling of wind farm is a prerequisite for prediction of annual energy production at the wind farm. In this study, we modeled 20 MW class Seongsan wind farm which has 10 wind turbines located at the eastern part of Jeju Island. WindSim based on the computational fluid dynamics was adopted for the estimation of power generation. The power curve and thrust coefficient with meteorology file were prepared for wind farm modelling. The meteorology file was produced based on the measured data of the Korea Wind Atlas provided by Korea Institute of Energy Research. Three types of wake models such as Jensen, Larsen, and Ishihara et al. wake models were applied to investigate the wake effects. From the result, Jensen and Ishihara wake models show nearly the same value of power generation whereas the Larsen wake model shows the largest value. New positions of wind turbines are proposed to reduce the wake loss, and to increase the annual energy production of the wind farm.

• 한국지역사회생활과학회지
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• 제22권1호
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• pp.5-20
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• 2011

It is very important that the development of rural tourism resources and contents for agritourism increases rural household income and vitalizes local economy. In this sense, accelerating the rural traditional food materials into resources plays significant roles for the local economy. The farm-restaurant project, as a part of a development of rural traditional foods can not only help popularize the rural food-culture, but it also promote the consumption of local products by urban customers. It is difficult to manage both types of restaurants which are the dining type and the experience-centered farm restaurants as a farmer. In particular, the managers of the farm restaurants have some operational problems in developing a new menu and an experiential-program using their local farm products. The purpose of this study was to present steps that can be used for the existing menu-improvement and developing new menu processes of the farm restaurants that have been in operation for more than two years. By the purpose of menu developing for a restaurant, this research is designed for the case study. For collecting date for the study, we gained knowledge about the issues concerning menus from in depth interviews with the managers in two subject farm restaurants. The results suggested that a new menu, such as table d'h$\^{o}$te, $\`{a}$ la carte meals, specialties, kids meal, various dressing, are based on solving issues such as a limitation of food materials and the necessity of a kids meal in dining type of farm restaurants. Also, the suggested new menu, such as seasonal specialties and side dishes, are based on solving issues such as urgent development of various experiential programs and necessity of seasonal specialties in experiential type of farm restaurants.

• 농촌지도와개발
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• 제15권4호
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• pp.659-681
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• 2008

The purpose of this study is to empirically analyze factors that influence farm managers' intentions to use an agricultural farm management information systems. It focused on "LFcenter System," a leading information system operated by the Rural Development Administration for farm management. Participants of this study are classified into two groups: a group of leading farm managers and a group fo regular farm managers. A total of 192 survey samples on users' intentions are collected; 85 samples from leading farm managers and 107 from regular farm managers. The theoretical background of this study is developed based on Theory of Reasoned Action(TRA), Technology Acceptance Model(TAM), Diffusion of Innovation(DOI), Social Cognitive Theory(SCT), and Theory of Planned Behavior(TPB). Partial Least Squares(PLS) method is used to test a proposed Structural Equation Model(SEM), including nine hypotheses. The differences between two groups are investigated using Smith-Satterthwait test. The findings from this study are: First of all, in terms of average comparison of most variables used in this study, a group of leading farm managers shows higher value that the other group in most cases. Second, hypothesis tests how that "subjective norms", "goal to study", "perceived usefulness", "perceived enjoyment", and "intention to use" significantly influence the intention to use an agricultural management information system in the group of leading farm managers. However, "subjective norms", "goal to study", "perceived ease of use", "perceived usefulness", "perceived enjoyment", and "intention to use" turned out to significantly influence the intention to use an agricultural management information system in the group of regular farms managers. Based on the results of Smith-Satterthwait test, compared with a group of leading farms managers, the impact of "goal to study" on "intention to use" is significantly stronger. On the other hand, in the group of leading farms managers, "perceived usefulness" and "perceived enjoyment" turned out to be main drivers of "intention to use."

• 농업과학연구
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• 제19권2호
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• pp.238-268
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• 1992

Since rural people migrated to urban area as a result of rapid industrialization in Korea, a significant proportion on agricultural labor farces has consistently reduced and therefore incurred labor shortage in rural area which might aggravate the farm household's economy. This sutdy suggests a long run plan of supplying agricultural machines for forage cultivation based on the survery of 102 livestock farm housecholds conducted in 1987, aimed at curtailing the labor costs which would contribute to improving the livestock farming management. The results of this study are as follows: 1. Among the 102 livestock farm household surveyed, 50 farm housecholds were found to cultivate 398a of grassland on average while other 52 farm households produced the forage on the 169a of land under cultivation averagely. 2. Over 50 percent of farm houseolds were reported to have their own agricultural machine for harvesting and cutting, however rates of mechanization in other operations such as mowing and sowing were less than 20 percent. 3. There were more than 50 percent of livestock farm households who have shown their intention to buy and operate their own farming machines when proprer opportunities are given. 4. In order to estimate the long-run demand for agricultural machines for livestock farm household considering current mechanization procedure, data for the machine's optimal capacty, growth of arable acreage for feed stuffs was collected and analyzed. 5. Based on the estimated demand, long range supply plan of livestock farming machines for the period of 1990-2010 was suggested. 6. Finally, measures for technological developement and finanacial support were suggested to implement so as to encourage the farmers' adoption of agricultural machines, and to achieve the goal of mechanization planning for the livestock farm household.