• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.5
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• pp.854-859
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• 2007

A wind farm consists of many wind generator(WG)s therefore, it is generally a complex power system. A wind farm as a distributed generation(DG) affects utility power system. If a conventional protection schemes are applied, it is difficult to detect faults correctly and the schemes can't provide proper coordination in some cases. This paper presents a protection algorithm for a wind farm which consists of a looped collection circuit. Because the proposed algorithm can distinguish between an internal fault and an external fault in a wind farm, The proposed algorithm can disconnect the faulted section in a wind farm. This algorithm is based on an overcurrent protection technique with the change of the ratio of the output current of a generator to the current of the looped line connected to each generator to collect the each generator's power. In addition, operating time of the algorithm is shortened by using the voltage drop at a generator collection point. The performance of the proposed algorithm was verified under various fault conditions using PSCAD/EMTDC simulations.

• Journal of Korean Society of Rural Planning
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• v.27 no.3
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• pp.93-102
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• 2021

This study was attempted to provide a scientific basis for the problem of location selection by spatial scale for efficient promotion of projects related to green care farm complex. Location potential assessment system in local government scale consists of two major components from demand-side and supply-side consideration. The demand-side aspect considered the characteristics of potential users, while supply-side aspect used total 18 indices over 8 divisions under 3 fields. For the location potential assessment in district scale, total 8 indices under 3 major divisions were considered based on biological, physical, social, and economic environment. The application results of the location potential evaluation system in local government scale(excluding metropolitan cities) showed high location potential in southern Gyeonggi Province and near Busan Metropolitan City. As a result of applying the district-scale location potential evaluation system to Geumsan-gun, Geumsan-eup, Chubu-myeon, and Jewon-myeon have high potential. Further studies to improve the applicability of the developed indices are recommended by enhancing assessment indices, complementing base data, and reinforcing with spatial analysis.

• Journal of Environmental Science International
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• v.19 no.9
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• pp.1169-1175
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• 2010

A case study for the design of a wind farm in complex terrain was carried out using the wind farm site analysis software OpenWind, which has an open-source platform and is free to use. The Youngdeok Wind Farm, constructed on mountainous terrain in Korea, was chosen as a model site; the design process reproduced using OpenWind. A comparison of the positions of the wind turbine derived from the OpenWind optimization process and the current positions were in good agreement. The annual energy production predicted by OpenWind compared with the prediction by the micrositing software, WindSim, were also validated to within 1%. Therefore, it was confirmed that OpenWind can be used for a practical wind farm design project. It is also anticipating that this paper will provide a prototype process for the design of a wind farm site and offer a database for the post-evaluation of a constructed wind farm in Korea.

• Journal of Korean Association for Spatial Structures
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• v.13 no.2
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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.

• Journal of the Korean Solar Energy Society
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• v.34 no.2
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• pp.82-90
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• 2014

The MERRA reanalysis data provided online by NASA was applied to predict the annual energy productions of two largest wind farms in Korea. The two wind farms, Gangwon wind farm and Yeongyang wind farm, are located on complex terrain. For the prediction, a commercial CFD program, WindSim, was used. The annual energy productions of the two wind farms were obtained for three separate years of MERRA data from June 2007 to May 2012, and the results were compared with the measured values listed in the CDM reports of the two wind farms. As the result, the prediction errors of six comparisons were within 9 percent when the availabilities of the wind farms were assumed to be 100 percent. Although further investigations are necessary, the MERRA reanalysis data seem useful tentatively to predict adjacent wind resources when measurement data are not available.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.3
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• pp.495-503
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• 1992

The internal and external outputs of the agricultural sub-systems of mixed livestock-crop farms in Pabna Bangladesh were analysed, to clarify the multiple functions of cattle in farm systems. Production systems with grazing areas were relatively more productive than those with no grazing. There was a tremendous variation in farm income, largely because of land area. An increase of one ha in land area was estimated to boost farm income by about 50%. Number of cattle, cattle off-take percentage and milk off-take per average cow related positively to farm income. As land area decreased the relative importance of cattle production increased. Crops were dominant in producing food for home consumption. Cattle contributed only 5-6 per cent to home consumption. Cattle supplied a significant cash income: 45 per cent in the villages with grazing areas and 57 per cent in the other villages. In future, the cash output from cattle will decline and emphasis will shift to the role of cattle in supporting crop production. Any research or development strategy for livestock needs to focus first on the importance of the complex relation between livestock and crops.

• Korean Journal of Organic Agriculture
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• v.16 no.4
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• pp.391-408
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• 2008

The overall focus of this study was to identify marketing and promotion strategies that can maintain and enhance environmentally friendly farm and organic production and processing activities. This is particularly important as the volume of environmentally friendly farm and organic produce that is generally available is increasing, and significant players, such as Organic Marketing Initiatives(OMI) and conventional marketing co-operatives, are becoming involved in the market. The rapid increase in production of environmentally friendly farm products and organic food is creating new and more complex challenges for marketing, from vegetable box schemes large co-operatives supplying the precise quality and volume required by supermarkets. A possible strategy for many farmers is to co-operate in regionally or nationally operating marketing initiatives. The main objective of any public relations(PR) activity should to enhance publicity and to improve an OMIs image. No promotion, no perception of OMI performance.

• Journal of Wind Energy
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• v.9 no.4
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• pp.32-39
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• 2018

In this study, the annual power production of a wind farm according to obstacles and wind data was predicted for the Garyeok-do wind farm in the Saemangeum area. The Saemangeum Garyeok-do wind farm was built in December 2014 by the Korea Rural Community Corporation. Currently, two 1.5 MW wind turbines manufactured by Hyundai Heavy Industries are installed and operated. Automatic weather station data from 2015 to 2017 was used as wind data to predict the annual power production of the wind farm for three consecutive years. For prediction, a commercial computational fluid dynamics tool known to be suitable for wind energy prediction in complex terrain was used. Predictions were made for three cases with or without considering obstacles and wind direction errors. The study found that by considering both obstacles and wind direction errors, prediction errors could be substantially reduced. The prediction errors were within 2.5 % or less for all three years.

• Communications for Statistical Applications and Methods
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• v.6 no.1
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• pp.131-142
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• 1999

Estimators for domains and approximate estimators of their variance are derived using post-stratified complex sample. Furthermore we propose an adjusted variance estimator of a domain mean in case of considering the post-stratified complex sample as simple random sample. A simulation study based on the data of Farm Household Economy Survey is presented to compare variance estimators numerically. From the study we showed that our adjusted variance estimator compensate for the under-estimation problem considerably.

• Journal of Sericultural and Entomological Science
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• v.55 no.1
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• pp.6-10
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• 2019

Current status and prospect of sericultural industry in Gyeonsangbukdo were examined through history and business of institute, sericultural status of Gyeongsangbukdo, purchasing results, and prospects of Gyeongsangbukdo. Silkworm & Insect Business Center was established in 1911 as Sericultural training institute. Original silkworm 400 case, and Nuedongchunghacho inoculant 100 box will be spreaded. Sericultural farmer is 339 and 41.5 percent on the whole country in 2016. Ten thousand kilogram of cocoon was purchased by institute in 2016. Farm income was increased to 13.7 million won and purchased cocoon 9,875 kg in 2017. To activate sericulture Gyeongsangbukdo will support Hanbok Institute in 2019 and make sericultural complex.