• Korean Chemical Engineering Research
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• v.48 no.1
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• pp.39-44
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• 2010

Economic feasibility of power generation system using waste woody biomass in a circulating fluidized bed combustor has been investigated. Effects of important variables such as capital investment, cost of waste wood, certified emission reduction(CER), system marginal price(SMP) on the benefit of business have been analyzed. Internal rate of return(IRR) was predicted as 16.67%, which implicates the business is promising based on the assumptions such as SMP of 99 Won/kWh, capital cost of 10.65 billion won, and complimentary providing of waste wood. Major factors affecting the benefit of business were as follows; system marginal price, operational rate, capital investment, expenditure of waste wood, certified emission reduction. In addition, it must be necessary to consider CHP power plant providing steam as one of the means to diversify sales network, for the management of the business risk.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.3
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• pp.421-426
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• 1994

Twelve cross bred cows ($300{\pm}20kg$) were fed a basal ration consisting of 1 kg concentrate and untreated or urea treated rice with or without urea-molasses-wheat bran lick block supplementation. The lick blocks were prepared locally using cement as a binding agent. The experiment lasted for 48 days consisting of a preliminary period of 14 days and a measurement period of 34 days. Daily dry ma tter intake (DMI) of straw and lick block, and daily milk yield were recorded during the measurement period. Intake of lick block when fed with untreated straw (US) was significantly higher (p < 0.01) than with urea treated (TS) straw (397 vs 307g $100kg^{-1}$), but lick block supplementation did not significantly affect the in take of US (1.80 vs 1.83kg $100kg^{-1}day^{-1}$) or TS (2.27 vs 2.17kg $100kg^{-1}day^{-1}$). Both urea treatment and lick block supplementation significantly increased (p < 0.01) the milk yield of cows, and the increase due to urea treatment was higher than that due to lick block supplementation. Benefit/cost ratio obtained for feeding US or TS with 1 kg dairy concentrate was similar (5.4), but the marginal return favours TS (5.4:1.0). The benefit/cost ratio for US and TS supplemented with lick block was 3.4 and 3.7. respectively, but the marginal return with US was higher than with TS (1.6:1.0 and 0.9:1.0, respectively).

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.6
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• pp.87-96
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• 2014

Since markup is defined as price over marginal cost by Hall(1988), the New Keynesians have intensively applied its definition in elucidating the relationship between market structure and business cycle. In lots of literatures markups proved to be counter cyclical empirically and theoretically. At the same time many studies analysed the determinants for markup in relation with business cycles. This paper establishes the markup equation based on the constant returns to scale production function including intermediate goods with technology being assumed to be AR(1) process and estimates the industrial markups in the Korean 5 service industries over the period 1975:1-2010:4. The paper also analyzed the markup determinants using the autoregressive distributed lag scheme ADL(1,1) in which the dependent variable and the single explanatory variable are each lagged once.

• Environmental and Resource Economics Review
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• v.27 no.1
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• pp.161-194
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• 2018

This study examines performances of cooperatives relative to investor-owned firms in the US electric power industry. Using a panel data of firms from 2001 to 2014, the results show that cooperatives operate under conditions of more difficult capital constraints associated with the higher cost of debt and limited access to external equity capital. While investor-owned utilities, especially the large utilities that are less capital constrained, take benefits from substantial scale economies existing in the industry, the marginal cost of operation substantially increases with output for cooperatives. I do not find differences in profitability between the two ownership structures, measured by return on assets and return on equity. Plant capacity utilization, which is a measure of plant efficiency conditional on the operation, is also not statistically different between the two groups.

• Current Photovoltaic Research
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• v.9 no.2
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• pp.51-58
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• 2021

Solar water pumping system (SWPS) is reliable and beneficial for Indian farmers in irrigation and crop production without accessing utility. The capability of easy installation and deployment, makes it an attractive option in remote areas without grid access. The selection of portable solar based pumps is pertaining to its longer life and economic viability due to lower running cost. The work presented in this manuscript intends to demonstrate performance analysis of portable systems. Consequent investigation reveals PSWS as the emerging option for rural household and marginal farmers. This can be attributed to the fact that, a considerable portion (around 45.7%) of the country's land is farmland and irrigation options are yet to reach farmers who entirely rely on rain water at present for harvesting of the crops. According to census 2010-2011 tube wells are the main source for irrigation amongst all other sources followed by canals. Out of the total 64.57-million-hectare net irrigation area, 48.16% is accounted by small and marginal holdings, 43.77% by semi-medium and medium holdings, and 8.07% by large holdings. As per 2015-16 census data, nearly 100 million farming households would struggle to make ends meet. The work included in this manuscript, presents the performance of different commercial brands and different technologies of DC surface solar water micro pumping systems have been studied (specifically, the centrifugal and reciprocating type pumps have been considered for analysis). The performance of the pumping systems has been analyzed and data is evaluated in terms of quantity of water impelled for specific head. The reciprocating pump has been observed to deliver the best system efficiency.

• The Journal of Advanced Prosthodontics
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• v.7 no.3
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• pp.191-198
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• 2015

PURPOSE. The purpose of this study was to compare the coronal bone level and patient satisfaction in 1-implant and 2-implant assisted mandibular overdentures. MATERIALS AND METHODS. Twenty patients who had maladaptive mandibular dentures were treated in this study. Patients were randomly divided into two groups. The first group received 1 implant (Simple line II, Implantium, South Korea) in their mandibular midline and the second group received 2 implants in their B and D regions (according to Misch's category). If the primary stability of each implant was at least 60 ISQ, ball attachment was placed and denture relined with soft liner. After 6 weeks, retentive cap incorporated with hard acrylic resin. In the 6 and 12 months recalls, periapical digital radiograph were made and visual analogue scale questionnaires were used to record patient satisfaction. The Friedman test was done for comparing the presurgical and postsurgical parameters in each group and the U-Mann Whitney test (P<.05) was done for comparison of post-treatment results between the two groups. RESULTS. All implants achieved sufficient primary stability to be immediately loaded. Patient satisfaction was high, and there were no significant differences between two groups (P>.05). In addition, mean marginal bone loss was $0.6{\pm}0.67$ mm in the first group and $0.6{\pm}0.51$ mm in the second group, after 12 month. Mean marginal bone loss showed no significant differences between two groups. CONCLUSION. This preliminary one-year result indicated that mandibular overdentures anchored to a single implant can be a safe and cost-effective method as a starting step for implant-overdenture treatment.

• Journal of Korean Society of Forest Science
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• v.81 no.3
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• pp.280-286
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• 1992

When the social cost-benefit analysis is applied for analyzing the public forestry investment, the choice of discount rate to be used in analysis is critical. In this paper, the social discount rate discussed in the public economics was introduced and the social time preference rate as a measure of that was estimated for Korea. The component parameters of the model used are : the elasticity of social marginal utility of consumption and the growth rate of real consumption. The results for the social time preference rate and the elasticity of social marginal utility of consumption are 6.2% and -1.38, respectively, which are plausible and thus can be used as a useful basis in establishing rational resource allocation policies.

• Journal of Korean Society of Rural Planning
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• v.24 no.2
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• pp.109-114
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• 2018

In this study, we estimate the greenhouse farmers' willingness to pay of agricultural water supply through pipeline. First, in the questionnaire design, orthogonal design and block design were used to enhance the ease of survey. Second, the theoretical model was constructed through the setting of the probability utility function, and the parameters were estimated by using the conditional logit model. Third, all of the estimation coefficients were statistically significant at the 1% significance level. The results of analysis are summarized as follows. First, the probability of selection is increased when maintenance is carried out by Korea Rural Community Corporation or local government. Second, the probability of selection is increased when agricultural water supply through pipeline is higher than the current level. Third, if the Korea Rural Community Corporation carries out maintenance management, the marginal willingness to pay is 44 won per ton. And if the local government carries out maintenance management, the marginal willingness to pay is 25 won per ton. Fourth, according to the quality level of agricultural water supply, the marginal willingness to pay is 101 won, 114 won and 120 won per ton, respectively. This study can be used as a basic data on the cost setting for agricultural water supply through pipeline.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.5
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• pp.29-35
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• 2015

The optimal greenhouse scales for controlled tomato should be studied because the increase of oil price and labor costs following the shortage of workforce makes greenhouse cultivation hard to gain profits. The purpose of this study is to estimate optimal production scales by greenhouse types for controlled tomato. The translog cost function is estimated based on the production cost survey data. The results can be summarized as follows: First, the average production cost of controlled tomato per kg decreases as the production scale increases. Second, according to the tomatoes farm of standard farming income data of RDA, the minimum production scale is 23 ton. Third, the estimated output of single-span greenhouse considering production scale with minimum average cost is 345 ton and production cost per kg is 1,476 won. The corresponding figures of multi-span greenhouse are 415 ton and 936 won, respectively. The study results can be used as basic materials for efficient decision making of tomato farmhouses and novice farmers. Also, the study shows that multi-span greenhouse should be encouraged to be built, since it requires lower marginal cost than single greenhouse. The results of this paper will help increase the income of farmhouses and cut expenses for the coming years.

• Korean Journal of Agricultural Science
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• v.24 no.1
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• pp.63-74
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• 1997

This study is aimed at identifying the value of marginal products(VMP) of agricultural labor, capital and land. The resources are the major portion of input costs of agricultural projects. To appraise economic feasibility of agricultural projects, the real value of the resources would be estimated by VMP of the inputs rather than by distorted actual market prices such as rural wages, rent and interest. To convert the market wage rate into shadow wage rate, covertion factor of 0.90 would be appicable based on the study results. To evaluate the right of way and compensation, VMP of land is recommendable to apply in land pricing rather than actural land rent prevailing in rural area which has been underrated on account of labor shortage and difficulty of farming. Discount rate as a opportunity cost of capital should be applied 7-8% considering the VMP of capital and interest rate of foreign loan from IBRD and ADB. For the successful appraisal of the agricultural projects, the recommendation of this study would be applied in the future.