• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.100-105
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• 2003

With the recent development of machining technology, high speed machining process is widely used for-the mold and difficult-to -cut-materials machining since it allows achieving high productivity and surface quality. However, during the high speed machining process, high cutting speed and feed rate can cause abrupt tool life decrease due to rapid rising of the cutting tool temperature. Such situation may cause increase of machining cost. Thus, in this study, developed optimization algorithm is applied to determine optimal machining variables for multiple high speed machining. The R-T characteristic curve for machining economics problems with a linear-lorarithmic tool life model is determined by applying sensitivity analysis. finally, a series of high speed machining experiments are performed to determine the desired optimal machining variables, and the results are analyzed.

• Asian-Australasian Journal of Animal Sciences
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• 제16권11호
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• pp.1572-1576
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• 2003

A growth trial of 180 days was conducted on 18 crossbred calves (6-9 months, $73.48{\pm}6.52kg)$ by randomly allotting to two complete diets and a conventional diet (6 in each group). The complete diets were formulated containing 40 per cent cotton straw, one processed in mash form and other subjected to expander-extruder pelletization (EEP). These two complete diets were compared with conventional system of feeding under which concentrate mixture and cotton straw were fed separately in a 60:40 ratio. The calves on EEP complete diet consumed more (p<0.01) DM in comparison to other two groups. The DMI per 100 kg body weight was similar among all the diets. The ADG was significantly (p<0.01) higher in calves fed EEP complete diets (815.4 g) followed by mash (627.0 g) in comparison to conventional diet (464.9 g). The DM intake per kg metabolic body weight was higher (p<0.01) on complete diet than conventional diet. The intakes of DCP (p<0.05), TDN (p<0.01), and ME (p<0.01) per kg metabolic body weight were significantly higher on EEP complete diet in comparison to mash and conventional diet. The water intake per kg DM intake was comparable among all the diets. The efficiency of DM utilisation was higher p (<0.05) on EEP complete diet (5.84) in comparison to conventional diet (7.41), whereas on mash diet it was intermediate (6.68). The efficiency of DCP utilization was similar in mash and EEP complete diet fed groups, which was higher (p<0.05) than that of the conventional diet. Expander-extrusion though increased the cost of production it reduced the cost of feed per unit live weight gain by 12.28% in comparison to its mash form and by 16.76% when concentrate and cotton straw were fed separately. The results indicated that blending of cotton straw along with concentrates in a complete diet increased the palatability of the straw in comparison to conventional system and expander extruder processing of cotton straw based complete diet gave better growth performance and may form an economic ration for growing crossbred calves.

• Asian-Australasian Journal of Animal Sciences
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• 제21권9호
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• pp.1318-1323
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• 2008

Corn distiller's dried grains with solubles (DDGS) is a completely new feed ingredient in the Korean feed market. There is an ever increasing need for the Korean feed industry to import and make the best of it as a high protein and high energy feed ingredient. A layer feeding trial was conducted for 10 weeks to investigate the effects of addition of light-colored DDGS to layer diets on laying performance, egg qualities and yolk fatty acid composition. Also, the economics of using DDGS in the Korean situation was analyzed. Nine hundred Hy-line Brown layers, 24 weeks of age, were employed in a feeding trial consisting of four dietary treatments (0, 10, 15, and 20% DDGS), and five replicates per treatment. All experimental diets were prepared as iso-protein (17%) and iso-calorie (TMEn 2,780 kcal/kg). The use of DDGS up to 20% in layer diets did not exert any influence on feed intake, laying rate, total egg mass, mean egg weight and feed conversion ratio (p>0.05). The color and breaking strength of eggshell, as well as the albumin height and Haugh unit were not affected by the addition of DDGS up to 20% in the diet. The yolk color was significantly increased by DDGS supplementation (p<0.05). As the DDGS level increased, the oleic acid content decreased, and the linoleic acid increased (p<0.05) in egg yolk. The degree of saturation of yolk fatty acids was not affected by DDGS supplementation. The inclusion of light-colored DDGS up to 20% in layer diets resulted in a decrease of feed cost per kg without any undesirable effect on laying performance. In conclusion, the light-colored DDGS (L* 56.65) could be used up to 20% in layer diets without any harmful effect on laying performance, and possibly provide economic benefits to the Korean poultry industry.

• 자원ㆍ환경경제연구
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• 제19권4호
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• pp.805-828
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• 2010

미국과 일부 EU 국가처럼 국내에서도 신재생에너지 보급 확산을 위해 시장기능을 강화하는 제도로서 신재생에너지 의무할당제(RPS)를 2012년 이후 도입할 예정이다. RPS의 도입을 통해 에너지 사업자에게 일정비율의 신재생에너지 공급을 의무화함으로써 신재생에너지 보급 확대에 기여한다는 것이다. 본 논문은 신재생에너지 의무할당제도의 도입에 따른 경제적 파급효과를 일반연산균형모형(CGE)을 이용한 정량적 분석을 통해 살펴보았다. 불완전 경쟁시장 가정 하에 내생적 성장모형(endogenous growth theory)에 기초한 CGE 모형을 이용하여 분석한 결과를 요약하면 다음과 같다. RPS 제도는 물량을 규제하기 때문에 목표량을 오차 없이 달성할 수 있다는 장점을 지니고 있다. 신재생에너지의 목표량이 정확히 달성됨에 따라 보다 큰 기술 확산 효과를 기대할 수 있다. 그러나 의무적으로 신재생에너지를 공급함에 따라 투자비용이 상승하여 중단기적으로 GDP가 감소할 가능성이 존재한다. 결국 장기적인 관점에서 신재생에너지의 보급을 확대하고 경제성장을 견인하는 신성장 동력으로 활용하고자 한다면 RPS 제도를 도입하는 것이 바람직하다.

• Journal of Animal Science and Technology
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• 제60권5호
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• pp.12.1-12.5
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• 2018

Background: The use of agroindustrial by-products in ruminant nutrition to be an interesting alternative in order to reduce production costs and environmental impacts arising from the inadequate destination of residues. The initial step of beer production yields a large volume of wet brewer's grains all year around, which is available at a low cost and has a high nutritional quality, and hence a big potential for animal production. Methods: Twenty-four Suffolk non-castrated male lambs, from simple parturition were kept in individual spots and allocated to four treatments constituted by four levels of substitution of sorghum silage by WBG (i.e.0; 33.5; 66.5 and 100% of substitution). It was used roughage: concentrate rate of 50:50, based on dry matter. Results: The ether extract intake increased while the acid detergent fiber intake decreased linearly ($P{\leq}0.05$). Substituion of sorghum silage by WBG did not change lambs' feed DMI, daily weight gain and feed conversion. Conclusion: The substitution of sorghum silage by WBG as roughage showed to be a viable alternative from the productive and economic point of view for finishing of feedlot lambs.

• Asian-Australasian Journal of Animal Sciences
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• 제13권10호
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• pp.1461-1466
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• 2000

The use of the dairy male calf for beef production has been found to be economically unprofitable during the past due to high cost of feeds and relatively low beef price. However, due to current shortage of domestic beef supply and rising beef price, this research aimed to assess feeding methods and costs and returns in raising dairy male calves for beef production under changing economic conditions. Two diets were compared: calves on an optimal feeding level were given milk replacer for 44 d and a concentrate (with ad lib. hay) to 150 kg bodyweight that contained 16% crude protein; those given a sub-optimal diet, more appropriate for smallholder farms, received milk replacer for 30 d and 14% CP concentrate. Twelve pairs of dairy male calves (average age 32 days) of Holstein-Friesian high grades were used, each pair having similar influencing factors such as weight, age, and genotype. Each animal was kept in a separate feeding stall until reaching the final weight of 150 kg. The results from this experiment showed that the differences of traits concerning growth performance and feed efficiency of the animals raised under the two feeding regimes were statistically nonsignificant. The optimal group was just slightly better, but the cost of production of the sub-optimal group was 24 percent lower (4,667 vs. 6,144 baht per animal) and the cost difference was highly significant. The results from this investigation showed that beef production from dairy male calves can be economically viable when sub-optimal feeding method is used and market beef price is at current level.

• Asian-Australasian Journal of Animal Sciences
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• 제26권9호
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• pp.1295-1303
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• 2013

The aim of this study was to determine the effect of different physical forms and urea treatment of rice straw on feed intake, rumen fermentation, and milk production. Four, multiparous Holstein crossbred dairy cows in mid-lactation with initial body weight (BW) of $409{\pm}20kg$ were randomly assigned according to a $4{\times}4$ Latin square design to receive four dietary treatments. The dietary treatments were as follows: untreated, long form rice straw (LRS), urea-treated (5%), long form rice straw (5% ULRS), urea-treated (2.5%), long form rice straw (2.5% ULRS) and urea-treated (2.5%), chopped (4 cm) rice straw (2.5% UCRS). Cows were fed with concentrate diets at a ratio of concentrate to milk yield of 1:2 and rice straw was fed ad libitum. The findings revealed significant improvements in total DM intake and digestibility by using long and short forms of urea-treated rice straw (p<0.05). Ruminal pH was not altered among all treatments (p>0.05), whereas ruminal $NH_3$-N, BUN and MUN were found to be increased (p<0.01) by urea-treated rice straw as compared with untreated rice straw. Volatile fatty acids (VFAs) concentrations especially those of acetic acid were decreased (p<0.05) and those of propionic acid were increased (p<0.05), thus acetic acid:propionic acid was subsequently lowered (p<0.05) in cows fed with long or short forms of urea-treated rice straw. The 2.5% ULRS and 2.5% UCRS had greater microbial protein synthesis and was greatest when cows were fed with 5% ULRS. The urea-treated rice straw fed groups had increased milk yield (p<0.05), while lower feed cost and greater economic return was in the 2.5% ULRS and 2.5% UCRS (p<0.01). From these results, it could be concluded that 2.5% ULRS could replace 5% ULRS used as a roughage source to maintain feed intake, rumen fermentation, efficiency of microbial protein synthesis, milk production and economical return in mid-lactating dairy cows.

• 한국작물학회:학술대회논문집
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• 한국작물학회 1999년도 추계 학술대회지
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• pp.102-144
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• 1999

The major problems of food crop cultivation in Korea are low yield of most crops except rice. inefficient cultivation techniques for aged farmers. and low international competibility. Therefore, development of cultivation techniques of food crops should aim the yield. quality improvement, labor reduction and production cost. The primary issue for increasing the yield of soybean, barely and wheat is to reduce the yield gap between the farmer's yield and recommended ones of experiment station. More advanced cultivation techniques needs to be developed. and/or the conventional breeding methods to be reconsidered. The newly developed labor-saving mechanized technique needs to reduce labor hours , and the cost of agricultural implements and machineries. In other words the labor-saving mechanized technique should be developed based on the improvement of total farming system as well as systemic fundamental innovation of cultural methods. The efficiency of solar energy use in food production of Korea in 1997 is as low as $0.52{\%}$ so there is much room to increase yield. It is recommendable that the concept of food Production should be changed to energy Producing efficiency Per unit area basis from volume and weight of food materials. Moreover, introduction of resonable cropping system is needed to increase yield of main crops, farmer's income, solar energy use efficiency, and decrease of land service expenditure. Current cropping system emphasized on economic crops. especially in vegetables , is not desirable for resonable use of arable land. stability of agricultural management and staple food crop self-sufficiency ratio. It is desirable to increase food crops . that are energy of carbohydrate and protein rich and land dependent crops. in cropping system. And the agronomist should develop the cultural methods to replace food crops for food self-sufficiency and stable farming management instead of economic crops in current cropping system. Low-input and environmentally-sound crop cultivation techniques, especially nitrogen-reducing culture technique which is directly related to food crop quality, also needs to be developed urgently. The extended cultivation of corn in upland and barely and wheat in lowland as a feed stuffs is recommended to prevent further decrease of food self-sufficiency ratio, which is mainly caused by the high reliance on imported feed grain. It is also considered that the calculation and presentation methods of standard agricultural income needs to be improved. The current calculation method uses unit land area of 10a regardless of crop kinds , characteristics of agricultural management and cultivation scale. So, it is apt to lead misunderstanding of farm income value. Therefore. it should show an income of average farmers for certain number of years. Research and developing system for food producing is not desirable because they are conducted currently individual crop and mono-culture basis. But actual agricultural income is usually earned by cropping system including upland and lowland. For example. the barley and wheat is usually cultivated in double cropping system. The cooperation among research institutes such as university agribusiness. government and farmers is indispensible. The public information and education on importance and consumption habit of food crops is necessary in Korean society to increase food self-sufficiency through nationwide cooperation.

• 한국가금학회지
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• 제21권1호
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• pp.21-34
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• 1994

우리의 채란 양계산업은 호당 사육 규모의 확대와 기술개선이 있었음에도 사육 기반은 낙후되었고 자동화 시설이 크게 도입되지 않았으며 영농 기록도 하지 않았다. 이는 아직도 기술 향상과 구조개선에 의해 생산비 절감이 가능함을 보인 것이다. 이 연구에서의 경쟁력 향상을 위해 채란양계 경영 내부에서 무엇이 문제인가를 판단하고 개선방향을 분석하는데 필요한 전산모형을 개발함으로써 그동안 실행되지 못했던 경영진단을 실시할 수 있고, 새로운 경영전략의 도입에 대한 경제적 합리성의 판단을 쉽게 할 수 있게 하였다. 또한 우리 농가의 실정에 적합하도록 입출력 모형을 세웠고, 컴퓨터에 대한 지식이 없는 농가도 쉽게 이용할 수 있도록 한글화시켰으며, 모형을 단순화 하였으면서도 농민이나 연구자들이 필요로 하는 내용은 포함토록 하였다. 우리나라의 개인용 컴퓨터의 보급이 크게 신장되었으나, 아직도 채란계 농가까지 널리 보급되지 않은 상태에서 채란계 농가가 쉽게 이용할 수 있는 이러한 프로그램들이 많이 개발되어야 채란계 농가에 컴퓨터의 보급이 촉진되고, 정보화 시대에 대응할 수 있기 때문에 이 모형은 상당한 유용성을 가진다고 볼 수 있다. 앞으로는 일반관리(사양관리, 방역관리, 사료, 작업관리) 등과 결합된 종합 경영관리 모형이 개발되어 농민이 컴퓨터에 쉽게 접근할 수 있도록 해야 한다.

• 한국BIM학회 논문집
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• 제5권4호
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• pp.53-62
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• 2015

Korea has been at the forefront of green growth initiatives. In 2008, the government declared the new vision toward 'low-carbon society and green growth'. The government subsidies and Feed-in Tariff (FIT) increased domestic usage of solar power by supplying photovoltaic housing and photovoltaic generation systems. Since 2000, solar power industry has been the world's fastest growing source with the annual growth rate of 52.5%. Especially, BIPV(Building Integrated Photovoltaic) systems are capturing a growing portion of the renewable energy market due to several reasons. BIPV consists of photovoltaic cells and modules integrated into the building envelope such as a roof or facades. By avoiding the cost of conventional materials, the incremental cost of photovoltaics is reduced and its life-cycle cost is improved. When it comes to atypical building, numerous problems occur because PV modules are flat, stationary, and have its orientation determined by building surface. However, previous studies mainly focused on improving installations of solar PV technologies on ground and rooftop photovoltaic array and developing prediction model to estimate the amount of produced electricity. Consequently, this paper discusses the problem during a planning and design stage of BIPV systems and suggests the method to select optimal design of the systems by applying the national strategy and economic policies. Furthermore, the paper aims to develop BIM tool based on the engineering knowledge from experts in order for non-specialists to design photovoltaic generation systems easily.