• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.857-860
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• 2009

This report examines the economic feasibility of a commercial 50,000 barrel per day direct/indirect coal liquefaction (DCL/ICL) facility to produce commercial-grade diesel and naphtha liquids from medium-sulfur bituminous coal. The scope of the study includes capital and operating cost estimates, sensitivity analysis and a comparative financial analysis. Based on plant capacity of 50,000BPD, employing Illinois #6 bituminous coal as feed coal the total capital cost appeared $3,994,858,000(DCL) and $4,942,976,000(ICL). Also, the internal rate of return of DCL/ICL appeared 13.27% and 12.68% on the base condition. In this case, coal price and sale price of products were the most influence factors. And ICL's payback period(6.8 years) was longer than DCL's (6.6 years). According to sensitivity analyses, the important factors on DCL/ICL processes were product sale price, feed coal price and the capital cost in order.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.149.2-149.2
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• 2011

This paper conducted an analysis of economic effects of offshore wind power in Korea with benefit/cost analysis. The existing feed-on tariff, which was too low to support wind power development, was recently replaced with a Renewable Portfolio Standard(RPS), effective from 2012. According to the new regulatory policy, The Korean government has announced a strategy to draw investments worth for offshore wind farms with a total capacity of 2.5 GW over the next eight years, which is expected the change of cost and benefit. After overview the offshore wind power development status, The effects on cost can be divided by economic, environmental and social factors. Each factor will be calculated and combined by both evaluating index and using Quantification methods. At the end, the implication for the evaluation of feasibility of offshore wind power of Korea will be done.

• 한국컴퓨터산업학회논문지
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• 제6권3호
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• pp.421-428
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• 2005

최근의 축산업은 대규모화와 자동화가 급진전 되면서 해당농장의 여건에 맞는 맞춤사료 개발시스템 구축이 절실하다. 오프라인상의 해당 각 농장들은 이에 대한 시스템 구축비용 등으로 인하여 많은 어려움을 겪고 있는 실정이다. 본 논문에서는 IT기술의 디지털 정보와 기술을 축산현장에 접목하는 시스템으로써 인터넷 서비스 환경에서 해당 양돈 농장에 맞춤화한 사료를 공급할 수 있는 시스템을 개발한다. 이 시스템은 경제적인 사료공급 뿐만 아니라 사료 생산비의 효율적인 운영 등 농${\cdot}$축산업의 업무 환경에 적합한 맞춤사료 DB구축을 가능케 하며 사육비 절감 등의 이점이 있다. 또한, 농장의 생산에 관련된 장치와 요소들을 디지털화하고 네트워크 환경을 구축하여 실시간대로 확인할 수 있는 21세기형 디지털 농${\cdot}$축산 솔루션으로써 기대 된다.

• 한국산학기술학회논문지
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• 제20권11호
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• pp.394-401
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• 2019

본 실험은 제한 급여에 따른 비육돈의 성장, 도체특성 및 경제성을 평가하기 위하여 수행하였다. 공시동물은 개시체중이 평균 81.52±1.11 kg인 3원 교잡종(Landrace×Yorkshire×Duroc)의 비육돈 24두를 사용하였으며, 2처리 12반복, 반복당 1두씩 완전임의 배치하여 27일간 진행하였다. 본 실험의 처리구는 무제한 급여(AF, ad libitum feeding)와 제한 급여(RF, restricted feeding)로 나누었으며, 제한 급여에서 증량이 필요한 경우 하루 전날 급여한 양의 10% 수준에서 증량하였다. 사양성적에서 RF의 일일사료섭취량이 AF에 비해 유의적으로 개선되었으나(p<0.001), 일당증체량과 사료효율은 처리구간의 유의적인 차이가 나타나지 않았다. 도체특성에서 도체중과 등지방두께는 AF와 RF간의 유의적인 차이가 나타나지 않았다. 도체등급에 따른 경제성 평가에서 두당 총 지육단가는 AF와 RF간의 유의적인 차이가 나타나지 않았다. 사료비에 따른 경제성 평가에서 RF의 총 사료섭취량과 총 사료섭취비가 유의적으로 낮게 나타났으나(p<0.001), 1 kg 증체 사료비는 AF와 RF간의 유의적인 차이가 없었다. 본 연구결과를 종합해보면 비육기 제한 급여는 무제한 급여에 비해 총 사료섭취량과 총 사료섭취비를 개선시켜 사료비를 저감시킬 수 있음을 시사한다.

• 한국공작기계학회논문집
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• 제10권6호
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• pp.126-134
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• 2001

Recently, high productivity and cost reduction becomes the most important target of industries due to the worldwide economic competition. One of these efforts is High Speed Machining(HSM), which reduces machining time with the increase of machining speed such as cutting speed and feedrate. It is very important, especially in case that the portion of machining time in production cost is high. This research suggests optimum cutting conditions to reduce cutting time with minimizing term error. For this study, a comprehensive model representing the texture of machining surface is developed, including rubbing phenomenon on the tip of ball end mill and expanded fibbing zone trajectory caused by tool deflection. Experiments show that the suggested set of feed and pick feed is optimum for maintaining the surface roughness identified by rubbing and low cutting speed in minimum.

• Asian-Australasian Journal of Animal Sciences
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• 제6권3호
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• pp.367-371
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• 1993

The feeding value of maize cob meal was investigated in a trial involving one hundred and forty Arbor Acre day-old chicks raised to eight weeks of age. The maize cob meal which contained 32.5% fibre, 2.5% protein and had a gross energy value of 2,550 kcal/kg, was incorporated into the experimental diets at either 0, 2.9, 5.8, 11.6 or 23.2% level. All diets were formulated to contain 3,200 kcal/kg of metabolizable energy and approximately 22% protein by varying the proportions of maize and whole cooked soyabean meal in the diets. The inclusion of maize cob meal up to 11.6% in the diet did not significantly (p>0.05) affect body weight gains, feed consumption and utilization, as well as carcass yield and dressing percentage. However, at the 23.2% level of maize cob meal inclusion, body weight gains, feed utilization and carcass yields were significantly (p<0.05) reduced. The use of maize cob meal reduced feed cost for raising birds and either maintained or improved gross profit returns with up to 11.6% level of inclusion in the diet. It was concluded that maize cob meal can be included up to 11.6% in the diet of broiler chickens provided dietary energy concentration is maintained at 3,200 kcal of metabolisable energy per kilogramme of feed by using high energy density feed ingredient such as boiled whole seed soyabean meal.

• 청정기술
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• 제28권2호
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• pp.182-192
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• 2022

This study provides an overview of the production costs of methane and hydrogen via water electrolysis-based hydrogen production followed by a methanation based methane production technology utilizing CO₂ from external sources. The study shows a comparative way for economic optimization of green methane generation using excess free electricity from renewable sources. The study initially developed the overall process on the Aspen Plus simulation tool. Aspen Plus estimated the capital expenditure for most of the equipment except for the methanation reactor and electrolyzer. The capital expenditure, the operating expenditure and the feed cost were used in a discounted cash flow based economic model for the methane production cost estimation. The study compared different reactor configurations as well. The same model was also used for a hydrogen production cost estimation. The optimized economic model estimated a methane production cost of $11.22/mcf when the plant is operating for 4000 hr/year and electricity is available for zero cost. Furthermore, a hydrogen production cost of $2.45/GJ was obtained. A sensitivity analysis was performed for the methane production cost as the electrolyzer cost varies across different electrolyzer types. A sensitivity study was also performed for the changing electricity cost, the number of operation hours per year and the plant capacity. The estimated levelized cost of methane (LCOM) in this study was less than or comparable with the existing studies available in the literature.

• Asian-Australasian Journal of Animal Sciences
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• 제21권1호
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• pp.66-74
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• 2008

Two experiments were conducted to assess the effect of replacing a conventional concentrate with mixed cassava (Manihot esculenta) foliage and legume (Phaseolus calcaratus) foliage. In Exp. 1, three rumen fistulated crossbred cows were used for in sacco rumen degradability studies. In vitro gas production was also studied. In Exp. 2, 11 crossbred F2 heifers (Red Sindhi$\times$Holstein Friesian), with initial live weight of $129{\pm}6kg$ and aged six months, were allocated in a Completely Randomized Design (CRD) to evaluate a mixture (ratio 3:1) of cassava and legume foliage (CA-LE feed) as a protein source compared to a traditional concentrate feed (Control) in diets based on fresh elephant grass (Pennisetum purpureum) and urea treated rice straw ad libitum. The Control feed was replaced by the CA-LE feed at levels of 0% (Control), 40% (CA-LE40), and 60% (CA-LE60) based on dry matter (DM). The in sacco degradation of CA-LE feed was higher than Control feed (p<0.05). After 48 h incubation the degradation of CA-LE feed and Control feed was 73% vs. 58% of DM and 83% vs. 65% of CP, respectively. The gas production of CA-LE feed was also significantly higher than of Control feed during the first 12 h of incubation. The results of the performance study (Exp. 2) showed that the level of CA-LE feed in the concentrate had no effect on total dry matter intake (p>0.05), but live weight gains (LWG) in CA-LE40 and CA-LE60 were significantly higher (551 and 609 g/d, respectively) than in the Control group (281 g/d). The intake of CP was higher (p<0.05) for the treatments CA-LE40 and CA-LE60 (556 and 590 g/d, respectively) compared to that of Control (458 g/d), while there was no significant difference in ME intake. The feed conversion ratio was 16.8, 9.0 and 7.9 kg DM/kg LWG in Control, CA-LE40 and CA-LE60, respectively. The feed cost of CA-LE40 and CA-LE60 corresponded to 43% and 35%, respectively, of the feed cost of Control feed. The best results were found when CA-LE feed replaced 60% of DM in Control feed and considerably decreased feed cost. It is concluded that feeding cassava foliage in combination with Phaseolus calcaratus legume as a protein supplement could be a potentially valuable strategy which leads to reduced feed costs and a more sustainable system in smallholder dairy production in Vietnam.

• Asian-Australasian Journal of Animal Sciences
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• 제30권5호
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• pp.672-682
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• 2017

Objective: This study was conducted to investigate the effects of probiotic, prebiotic and synbiotic with and without feed restriction on broilers performance, blood parameters, carcass characteristics, and feed cost of production from 1 to 56 days of age. Methods: Two hundred and forty unsexed one day-old chicks of Arbor Acres breed were used. Two trials, I and II, were conducted, with 120 birds in both. Each trial was divided into 4 equal groups. The birds in trial I were fed ad libitum throughout the experiment, while the chicks in trial II were fed ad libitum during the first week of age, then subjected to 5 hours/d of feed restriction from the beginning of the second week up to the end of the experiment. In both trials, the birds in group 1 were fed on a control diet while the other groups were given the same control diet supplemented either with a probiotic in group 2, prebiotic in group 3, or synbiotic in group 4. Results: It was found that chicks fed diets supplemented with probiotic, prebiotic and synbiotic (with and without feed restriction) exhibited higher body weight and feed efficiency than chicks fed the control diets. The feed additives in both trials did not affect hemoglobin, serum total protein, albumin, globulin, glucose, and total cholesterol, except the packed cell volume which was increased in the additive treatments with restriction at the end of the experiment. Moreover, the dietary treatments did not influence the carcass yield. However, the relative weights of liver, gizzard and proventriculus, small intestine and bursa of fabricius were found to be increased. The additives decreased the visible fat in the carcass, with more decreasing effect in the additive groups with restriction. The lowest feed cost per kg of weight gain was observed in the birds fed diets supplemented with synbiotic, probiotic and prebiotic. Feed restriction improved the feed conversion ratio, economic return, but decreased the feed intake, serum total cholesterol and visible fat in comparison with non-restricted groups. Conclusion: The biological feed additives could be routinely added to broiler diets, especially when a feed restriction program is followed. Finally, it can be recommended to restrict feed, and add probiotic or synbiotic to increase weight, improve feed conversion rate and reduce feed cost of production.

• 수산경영론집
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• 제45권1호
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• pp.95-107
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• 2014

This study is aimed to analyze the economic performance of black rockfish aquaculture by standardizing cost structures by region and farming size. The result of survey on farming and sale condition in each region, stocking density, survival rate, juvenile price, and unit production was the highest at Yeosu and Tongyeong, Heuksando showed the lowest. While rearing period was the longest at Tongyeong, the shortest region was Yeosu and Wando. In farming cost structure by region, amount of feeing was the highest at Tongyeong and Yeosu, and the lowest was Heuksando. Cost of medicine was high in Wando and Taean region, Yeosu and Hecksando was low. In case of farm size, feed cost ratio was high in the order of medium(0.75ha), small(0.25ha) and large(1.25ha) size. Standard production cost at every farm size of Heuksando showed the lowest among these regions. Taean and Yeosu was middle, and Tongyeong and Wando was the highest. According to the income, profit rate and investment return of farm size in all regions, as the bigger farm size, the higher income and profit rate was revealed. However, in case of Wando, Taean, and Heuksando which regions has high investment return, medium farm size was higher than large size. The result of economic analysis according to various factors, economic feasibility of black rockfish aquaculture in marine floating cage was showed significant changes by rearing and market condition.