• Journal of applied mathematics & informatics
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• v.26 no.1_2
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• pp.337-347
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• 2008

Based on social welfare maximum theory, the optimal scale of power plants entering generation power market being is researched. A static non-cooperative game model for short-term optimization of power plants with different cost is presented. And the equilibrium solutions and the total social welfare are obtained. According to principle of maximum social welfare selection, the optimization model is solved, optimal number of power plants entering the market is determined. The optimization results can not only increase the customer surplus and improve power production efficiency, but also sustain normal profits of power plants and scale economy of power production, and the waste of resource can also be avoided. At last, case results show that the proposed model is efficient.

• Transactions of Materials Processing
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• v.21 no.8
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• pp.467-472
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• 2012

Shaving shear-welding is a solid-state welding process, which utilizes plastic deformation of surplus material. The solid-state nature of this process contributes to high integrity and strength of the weld. The objective of this study was to investigate the effects of process variables on the material flow patterns and identify the process condition for obtaining the best weld. FEM simulations were carried out along with experimental characterizations. The results showed the importance of the cutter angles and the overlap lengths, and helped attain the optimum shaving shear-welding die and the best process condition.

• Korean Journal of Microbiology
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• v.28 no.3
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• pp.249-257
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• 1990

In the course of operating the accommodative and detoxifying mechanism against cadmium, its physio-biochemical changes were observed in Klebsiella aerogenes ATCC 10031. Changes of enzyme activity concerned phosphate metabolism, changes of phospholipid composition and in view of energy metabolism the changes of the nucleotide pool were examined. Activities of both alkaline and acid phosphatase were derepressed 4-10 folds under cadmium added cultures. Moreover, production of phospholipid such as lysophosphatidyl choline (LPC), phosphatidyl serine (PS) and phosphatidyl ethanolamone (PE) was increased and uridylate nucleotide pool was increased under Cd-surplus culture. These results i.e. overproduction of phosphatase catalyzing phosphate residue, increase of the production of PE and PS which have a close affinity with cadmium, and indrease of uridylate nucleotide pool used as a carrier of polysaccharide synthesis like bacterial capsule exhibited cellular responses for active defence against Cd-pressure. It was postulated that these phenomena should play another assistant roles in Cd-detoxifing mechanism.

• Ocean and Polar Research
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• v.39 no.4
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• pp.301-318
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• 2017

The production of Korean offshore fisheries has been gradually decreasing due to the severe depletion of offshore fisheries resources caused by excessive fishing efforts. The production of the offshore fisheries in 2016 was the lowest since 1975. So the federal and local governments in Korea adopted and implemented various fisheries management plans and policies in order to restore fisheries resources. However, these plans and polices have not been successful in re-establishing fisheries resources. Thus, in order to accurately diagnose the situation with regard to offshore fisheries, this study sought to estimate not only the return to scale by fishing gear of offshore fisheries, but marginal productivity of individual fishing gear based on production factors derived from offshore fisheries production functions. The study was organized in the following manner. First of all, this study estimates production functions of offshore fisheries. The Cobb-Douglas and the translog production functions are adopted as offshore fisheries production functions. Specifically, the functions are estimated by crew, vessels, and offshore resource as production factors. The offshore resource is estimated by the Clarke Yoshimoto Pooley model based on the surplus production model. Secondly, the fisheries production functions are extended to the fixed-effect model and the random-effect model with panel data. Thirdly, this study analyzes the return to scale of offshore fisheries and the marginal productivity of the production factors from the estimated offshore fisheries production function. In conclusion, this study suggests plans and countermeasures for productivity improvement by group (labor intensive or technology intensive) based on the characteristics of individual offshore fishing gear.

• Journal of Dairy Science and Biotechnology
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• v.32 no.2
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• pp.71-76
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• 2014

The Netherlands produce more than 11 million tonnes of milk per year, and approximately 60% of the milk is exported. Dutch milk production is five times higher than that of Korea, even though Korea comprises a land area three times greater than the Netherlands. Upscaling and intensification have characterized the Dutch way of dairy farming since 1960, and adverse effects of the intensification of dairy farming became evident from the late 1970s and early 1980s onwards. The transition toward a more sustainable farming system is a central element of the Dutch agenda for the reconstruction of the livestock production sector. The environmental problems in Dutch dairy farming in the 1980s have led to the establishment of the experimental dairy farm "De Marke" which aims at improving the utilization of fertilizers and feeds, through minimizing nutrient requirements, maximizing the use of nutrients in organic manure and homegrown feeds, and through the targeted use of fertilizers and feeds. 85 cows at "De Marke" produce 720 tonnes of milk per year, using 55 ha of pasture in a sustainable manner. That means, 150,000 ha of pasture are required to produce 2 million tonnes of milk, which the current milk production of Korea. It is urgent to provide sufficient pasture for sustainable milk production in Korea, and primarily the transition to pasture of surplus rice paddies, resulting from of a decrease in rice consumption, should be considered.

• The Journal of Fisheries Business Administration
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• v.44 no.2
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• pp.101-109
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• 2013

This study is aimed to analyze investment effects of fisheries R&D projects of the National Fisheries Research and Development Institute(NFRDI). In the analysis, Granger causal relations between R&D investment and fisheries production are tested. In addition, time-lag effects of fisheries R&D investment are estimated with an impulse response analysis and investment effects of R&D projects are estimated by changes of social surplus. Results indicate that there exists an Granger-causality between R&D investment and fisheries production and fisheries production responds to the fisheries R&D shock about three years after the initial shock. The magnitudes of the impacts increase until a peak is reached 5~7 years and the impacts decline to zero after 25 years. As investment effects, it is shown that the internal rate of returns of fisheries R&D investment is 55.2%.

• Journal of IKEEE
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• v.23 no.2
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• pp.380-387
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• 2019

In recent years, solar energy PV/T research has been actively pursued by complementing solar heat acquisition and solar energy acquisition, and PV/T energy efficiency is generally excellent. In this study, the annual energy demand is calculated based on one building, and the energy production when PV / T installed on the roof and the energy production when PV are installed are compared and analyzed by simulation case. In conclusion, Busan which is the southern province in Korea, has the largest amount of energy generation, and introducing the concept of sharing surplus energy, excluding energy demand from generation. As a result, it can be supplied up to 3.3 households.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.4
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• pp.483-486
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• 2000

The influence of feed allowance on intake and nutrient utilization by Barbari goats given green maize (Zea mays) and potential feeding value of left-overs were studied. The goats were offered food at 3 levels to give left-overs of about 20% (T-1), 35% (T-2) and 50% (T-3) DM of offered amount. A marked effect of refusal rate on intake and digestibility of nutrients was found. The DMI, g/kg $W^{0.75}$ increased from 39.86 in T-1 to 50.91 and 66.55 g in groups T-2 and T-3, respectively. Allowing selective consumption at higher levels (T-2 and T-3), the intake of TDN and DCP from green maize was found not only to meet the maintenance requirement but provided surplus energy and protein for substantial production. The variability in diet selectivity between goats under different treatments was pronounced. As the level of food excess increased to T-3, the left overs had a higher IVDMD and crude protein and decreased cell wall constituents (p<0.05). Considering the substantial increase in intake and digestibility from feeding green maize at high allowances to goats, further studies are needed to develop practical feeding strategies.

• Korean Journal of Agricultural Science
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• v.23 no.1
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• pp.150-158
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• 1996

The potato has been used as a part of key staple foods in Korea. Recently, the demand for the potato tends to increase due to its nutritional Quality, and the Quantity of imports has rapidly been increasing. Contamination of seed potato by pathogens especially could cause a severe reduction of total production. In order to solve the problem, Korea Research Insistute of Bioscience and Biotechnology(KBIBB) developed the new commodity called a "potato microtuber". Before its production and distribution, researches on new commodity should be undertaken in many aspects, especially in terms of economic aspects. The main objectives of this study are to measure the economic value of the potato microtubers and to forecast its spreading effects and to examine the Contingent Valuation Method(CVM) could be accepted in the economic analysis for a new agricultural product, here in potato microtubers. Through the regression results, the consumer behavior analysis had performed for potential users of potato microtubers, and through the demand function derived by the consequence of functional relationship, consumer's surplus was estimated.

• Korean Journal of Poultry Science
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• v.41 no.4
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• pp.313-322
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• 2014

Evaluation of energy in the diet is very important in animal nutrition because food intake is strongly influenced by the energy content of the diet. This means that the intake of other nutrients, such as amino acids, is affected by their ratio to energy content. Poultry can control their energy intake over a range of energy: protein ratios. Energy: protein ratio also affects the growth and body composition. Therefore we need to know what extent the relationship between energy and dietary protein influences the bird's performance. To predict the energy value of the diet or its chemical constituents, researchers have been working on modelling using the equations of the major biochemical pathways in terms of ATP generation and utilization. The activity of feeding and the metabolism caused by digestion and assimilation of food increase the animal's heat production and it can be measured by calorimetry technique. Theoretically, surplus amino acids which are not needed for protein synthesis stimulate an additional increase in metabolic rate and lead to increased energetic costs of catabolism and excretion. However, it has sometimes been shown that there was no measurable diet-induced thermoregulatory effect when an imbalanced amino acid mixture was fed. All these aspects are discussed in this review.