• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.III
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• pp.613-622
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• 2000

Watering operation for oyster mushroom growing houses is regarded as drudgery and time consuming farm operation for growers. Most of mushroom growing beds in oyster mushroom growing houses are designed as two-row with four floor beds, therefore the watering and ventilation between the bed floors are much difficult for farmers because of its structural design. The study aimed to reduce the watering operation and improve the mushroom growing environment through the humidification and air supply on mushroom growing beds. Results showed that appropriate size of nozzle is between 0.8~0.5ml/s for the humidification and higher than the 2.0ml/s for the watering. The optimum water supply pressure was regarded as between 1.0~2.0MPa and the uniform distribution of droplet on the bed showed on air flow speed of 14m/s. The prototype was equipped with twin nozzle with. the humidification nozzle of 0.85ml/s and watering nozzle of 5.0ml/s, and the air blast fan with the air speed of 10m/sec in each air spout. In the field test in a practical scale mushroom growing house, it was well operated dependant on the set desire by a electric control unit. The machine can be practically used as air blast watering and air blast humidification for oyster mushroom growing farms without manual.

• 한국잠사곤충학회지
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• 제44권2호
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• pp.51-55
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• 2002

한반도에 자생하는 돌뽕나무(Morus tiliaefolia)와 몽고뽕나무(Morus mongolica)의 자연분포지는 다음과 같다. 1. 돌뽕나무는 강원도 화천읍(북위 38$^{\circ}$8')을 북한으로 하여 산간 내륙과 해안 도서지방에 많이 분포하며 동해 난류의 영향으로 함경북도 명천군 칠보산에도 분포한다. 2. 몽고뽕나무는 황해도 재령군 장수면(북위 38$^{\circ}$15')이북의 백두대간 서쪽에 분포하며 이례적으로 강원도 삼척지방(북위 37$^{\circ}$24')에도 자생한다.

• 한국지리정보학회지
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• 제19권1호
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• pp.94-105
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• 2016

본 연구에서는 30년간의 전자기후자료와 현지조사자료를 활용하여 로지스틱 회귀모형을 이용한 상록활엽수림의 생육분포 확률을 평가하였다. 로지스틱 회귀모형에 의한 생육분포 확률은 33~84% 범위를 보이고 있는데 특히, 고도가 높아질수록 생육분포 확률은 낮아지는 패턴을 보이고 있다. 아울러 온 난대림육성권역에서 생육분포 확률이 63~83%로 가장 높은 것으로 추정되었다.

• 한국환경농학회지
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• 제35권4호
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• pp.302-305
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• 2016

BACKGROUND: The northeast district of China, especially Liaoning province, Jilin province, and Heilongjiang province, is one of the largest agricultural production regions in China. These regions play a significant role in ensuring food security. Accumulated temperature such as growing degree days (GDD) is an important environmental factor for plant growth and yield. Therefore, in this study, temporal and spatial distribution of GDD for maize was examined as a basis to estimate the growth and yield of maize in these regions. METHODS AND RESULTS: Meteorological date produced by NASA (MERRA-2) was used to estimate GDD of maize at this study sites. The GDD was calculated from sowing (May 1) to harvesting (Sep. 30). The average GDD of this region between 2010 and 2015 was $1323.0^{\circ}C$ day (595.3-1838.9). The spatial distribution of GDD showed a similar pattern during the different years surveyed. Double cropping for maize could be in only Liaoning province, northwestern Jilin province, and western and eastern Heilongjiang province where the GDD was over $1600^{\circ}C$day. However, The GDD in eastern Heilongjiang province was varied by year. CONCLUSION: The GDD of maize in northeast district of China was varied spatially, but similar among recent six years at the same region. This result can be used to predict growth stage and yield of maize at these regions.

• Asian-Australasian Journal of Animal Sciences
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• 제32권5호
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• pp.742-747
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• 2019

Objective: A concentration of airborne bacteria generated from swine houses is recognized to be relatively higher than other work places and it is essential to optimally manage it to prevent farmers' respiratory diseases. This study was conducted to assess the distribution characteristics of airborne bacteria in swine houses located at South Korea. Methods: A total 27 pig buildings of the enclosed type operated with mechanical ventilation system by a side wall fan and deep-pit manure system with slats were surveyed. Air samples were collected at 1.0 m above the middle floor in pig housing room. A six-stage viable particulate cascade impactor was used to identify the distribution of the sizes of particles in diameter. Results: Seasonal mean levels of airborne bacteria in the housing rooms of gestation/farrowing pigs, nursery pigs and growing/fattening pigs were 3,428(${\pm}1,244$) colony forming unit $(cfu)/m^3$, $8,325({\pm}3,209)cfu/m$, and $13,254({\pm}6,108)cfu/m^3$ for spring; $9,824({\pm}2,157)cfu/m^3$, $18,254({\pm}5,166)cfu/m^3$, and $24,088({\pm}9,274)cfu/m^3$ for summer; $1,707({\pm}957)cfu/m^3$, $4,258({\pm}1,438)cfu/m^3$, and $8,254({\pm}2,416)cfu/m^3$ for autumn; and $2,322({\pm}1,352)cfu/m^3$, $6,124({\pm}1,527)cfu/m^3$ and $12,470({\pm}4,869)cfu/m^3$ for winter, respectively. Conclusion: Concentrations of airborne bacteria according to pig housing type were highest in growing/fattening housing room followed by nursery housing room and gestation/farrowing housing room. In terms of seasonal aspect, the pig building showed the highest levels of airborne bacteria in summer followed by spring, winter and autumn. The respirable airborne bacteria which are ranged between 0.6 and $4.7{\mu}m$ accounted for approximately 60% compared to total airborne bacteria regardless of pig housing type.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.525-526
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• 2007

Recently, there has been growing interest in utilizing distributed generation (DG). However, an insertion of DG to existing distribution system can cause several problems such as voltage variations, harmonics, protective coordination, increasing fault current etc,. The typical protection system of the existing distribution system is designed for radial network. But penetration of DG to distribution system changes existing unidirectional power flow to bidirectional power flow. Therefore, investigation to cover whole field of distribution system must be accomplished such as changing of protection devices rating by increasing fault current, reevaluation of protective coordination. This paper presents that PSCAD/EMTDC simulations was accomplished to analyze effect of DG on the distribution protective coordination. In addition, directional recloser-sectionalizer coordination are evaluates distribution system with DG by using PSCAD/EMTDC simulation.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
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• pp.107-114
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• 1999

The large-scale distribution of crops Is usually determined by climate. We present the results of a climate-crop prediction based on spatial bio-physical process model approach, implemented in a GIS (Geographic Information System) environment using several regional and global agriculture-environmental databases. The model utilizes daily climate data like temperature, rainfall, solar radiation being generated stocastically by in-built model weather generator to determine the daily biomass and finally the crop yield. Crops are characterized by their specific growing period requirements, photosynthesis, respiration properties and harvesting index properties. Temperature and radiation during the growing period controls the development of each crop. The model simulates geographic/spatial distribution of climate by which a crop-growing belt can also be determined. The model takes both irrigated and non-irrigated area crop productivity into account and the potential increase in productivity by the technical means like mechanization is not considered. All the management input given at the base year 1995 was kept same for the next twenty-year changes until 2015. The simulated distributions of crops under current climatic conditions coincide largely with the current agricultural or specific crop growing regions. Simulation with assumed weather generated derived climate change scenario illustrate changes in the agricultural potential. There are large regional differences in the response across the country. The north-south and east-west regions responded differently with projected climate changes with increased and decreased productivity depending upon the crops and scenarios separately. When water was limiting or facilitating as non-irrigated and irrigated area crop-production effects of temperature rise and higher $CO_2$ levels were different depending on the crops and accordingly their production. Rise in temperature led to yield reduction in case of maize and rice whereas a gain was observed for wheat crop, doubled $CO_2$ concentration enhanced yield for all crops and their several combinations behaved differently with increase or decrease in yields. Finally, with this spatial modeling approach we succeeded in quantifying the crop productivity which may bring regional disparities under the different climatic scenarios where one region may become better off and the other may go worse off.

• 한국축산시설환경학회지
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• 제14권1호
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• pp.39-46
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• 2008

본 실험은 무창육성 비육돈사에 있어서 여름과 겨울철 환기를 할 때 공기 유입구에서의 공기속도가 환경에 미치는 영향을 조사하고자 CFD를 이용한 모델을 설정하였고, 현장실험을 통한 결과와 CFD 모델의 공기유속 결과를 서로 비교하였다. 공기속도에 있어서 수학적인 모델은 현장실험 결과와 매우 유사하게 나타났다. 환기시스템에서의 공기흐름은 양쪽 측벽 슬롯 판넬을 통하여 공급하였으며 겨울철은 $2{\sim}2.5m/s$ 였고, 여름철은 0.8 m/s 전후였다. 이상의 연구 결과 여름철과 겨울철 모두 해석 Model과 실험 무창육성 비육돈사내 측정 결과 평균 유속은 근소한 차이로 나타나 공기유동 해석 연구에 있어서 CFD 시뮬레이션의 적용으로 합리적인 결과를 도출할 수 있음을 확인하였다.

• 한국초지조사료학회지
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• 제30권4호
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• pp.301-308
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• 2010

본 연구는 Sheep fescue와 외국산야생화를 혼파하여 조성한 야생화초지의 생육특성, 계절분포 및 식생비율을 구명하고자 충남대학교내 초지시험포장에서 2007년 10월부터 2009년 12월까지 수행하였다. 공시초종은 기본초종인 잔디형 목초로 Sheep fescue (Azure)와 외국산 야생화 22종을 공시하였다. 개화시의 야생화의 평균초장은 1년차(2008) 29.7 cm, 2년차(2009) 34.1 cm 이었다. 꽃 색은 8가지로 다양하였으나 8월, 9월 및 10월에는 2가지색으로 단순화되었다. 개화는 4∼6월에 편중되었고, 8월부터는 야생화의 개화 및 영속성유지에 상당한 어려움이 있었다. 특히, 2년차(2009)에는 월동 후 일년생 야생화초종이 감소되어 꽃 색, 계절분포 및 영속성유지는 문제시되었다. 야생화초지의 연평균 식생비율은 야생화, Sheep fescue 및 잡초가 각각 1년차(2008)에는 21%, 64% 및 15%이었고, 2년차(2009)에는 각각 19%, 65% 및 16%를 유지하였다. 이상의 결과로 보아 외국산 야생화초지의 조성은 야생화의 계절분포 및 영속성 유지에 어려움이 있어 다년생 및 여름철 개화 초종 도입 등 더 다양한 야생화 초종의 선발과 혼파조합방안이 검토되어야 하겠다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.180-182
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• 1992

In spite of recent stagnation, the rate of electric consumption has highly grown in accordance with a high cultural livings, Also, a usage of electric energy is growing with development of multi-information society. To make the matter worse, hard work of highest order is required because distribution system are widely spread and complex. And consummers demand for the electricity of good quality and it is obstracle to be not able to train related technitian for maintenance without an interruption of electric power. It is sure the counterplan of uninterruption of electric power is very necessary. In this paper, considering the working circumstances, we presented the necessity of work method, the effects and the future prospect for uninterruption power supply.