• Journal of the Korean Institute of Landscape Architecture
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• v.24 no.1
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• pp.55-64
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• 1996

The size of leisure space has been determined on the basis of the annual and peak day's number of visitor, turnover rate, and size per visitor. But the past models have no theoretical base and practical errors on the many cases. So, this study was carried out to build and test a new theoretical model for selecting a optimal size of theme park. The basic concept of the model building is the break-even point analysis of cost-volume-profit relation. That is, Gain-Loss of theme park is determined by marginal profit and fixed cost by size. YongIn Farmland was selected as a model test case.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.334-336
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• 2000

In Korea, the CCGTs have been installed to about 25% of the total generating capacity. Generally CCGTs determine the System Marginal Prices(SMP) in Cost Based Generation Pool. So the scheduling of CCGTs is very important in daily generation scheduling. This paper describes the scheduling of CCGTs which considers the operating characteristics of them. We use lagrangian relaxation method which decomposes the unit committment problem into the subproblems of the individual unit. In the CCGT subproblem, we define the cost function of CCGT in two way. In Case study, the daily generation scheduling is performed using the data of Korean thermal system.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.10-12
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• 2000

The electric utility industry around the world is undergoing a revolutionary transition from vertically integrated monopoly structure to a competitive industry. Electric market price changes hourly because suppliers and customers participate in a open market competitively. In this paper a web program developed wi function of OPF calculation. This program is re by a perl language. Also We calculated the marginal cost and the congestion charge shadow price resulted from the OPF.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.580-583
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• 2008

As the construction of renewable energy generators is on the rise and gets bigger in size, researchers pay more and more attention to the impact of such facilities on the power market as well as on the stability of power grid system. In Korea, while studies on the latter, including calculating the marginal capacity of renewable energy generators, is being made, those on the former has not yet been performed. As such, this paper analyses the impact of a big renewable energy generators on the price and transaction cost of domestic power market and proposes ideas to minimize such influence by applying the technology of forecasting renewable energy.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1566-1574
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• 2004

This study tried to find out alternatives adjusting basic fare using customer survey. But it merely verified that train fare decision is made by government's role and market status. Also, it has a limitation deciding resonable fare of KTX that average cost and marginal cost calculation is impossible because Korean National Railroad does not follow 'Activity Based Costing'. It is rational fare decision that performing survey to railroad experts and general customers, and compare two results. Summarizing results of this study, 1. The hypothesis 'Experts' perceived fare level of KTX is higher than that of general customer. 'is carried. It suggests that following experts' opinion with general customer's is very rational method to decide fare level. 2. The hypothesis 'Experts expect lower level of fare discount rate than general customer.' is carried. 3. It is hard to decide priority among many kinds of discount for difference of two group's preference. However, following recent research project is maximized by discounting fare 30$\%$ on 40$\%$ of total passenger and expand number of discount kinds step by step are desirable.

• Journal of the military operations research society of Korea
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• v.16 no.2
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• pp.83-95
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• 1990

This paper addresses the problem of determining the optimal number of spares for a system consisting of multi-item parts. In commercial sector, the cost minimization is mainly considered as an objective functions in most inventory models. However, in the military inventory systems, it is more stressed on maximizing the system availability than minimizing the system cost because the field commander always wants the system to be in perfect working condition to prepare against an emergence case. In this point of view, this paper develops an inventory model which decides the optimal number of spares by minimizing units short and simultaneously achieving a certain level of system availability. Solution algorithms are derived using the generalized Lagrange multiplier approach and marginal analysis approach. Sample data and output results are provided and sensitivity analysis is performed as the level of system availability changes in order to decide the optimal number of spares and availability in terms of economic sense.

• Journal of Korean Institute of Industrial Engineers
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• v.18 no.1
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• pp.47-62
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• 1992

This paper describes a procedure for optimizing the route selection and production conditions in alternate process plans under a cellular manufacturing environment. The type of production is mainly production-to-order which deals with unexpected products as the changes factor. The flexible cellular manufacturing can be viewed as a complete unification of both flexible manufacturing process and flexible production management. The integrated problem for designing flexible cellular manufacturing associated with determining the optimal values of the machining speeds, overtime, and intercell flow is formulated as Nonlinear Mixed Integer Programming(NMIP) in order to minimize total production change cost. This is achieved by introducing the marginal cost analysis into the NMIP, which will compute the optimal machining speed, overtime, intercell flow, and routing. The application of this procedure offers greater flexibility to take advantage of the cellular manufacturing due to the optimum use of resources. A solution procedure for this problem was developed and a numerical example is included.

• Korean Journal of Agricultural Science
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• v.31 no.1
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• pp.53-75
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• 2004

This study is aimed at identifying the national economic value of the irrigation facilities by reviewing the existing papers on economic values of the irrigation facilities and presenting current status of dual O & M problems of the irrigation facilities. This study suggested the unified O & M system rather than continuing the existing dual O & M system of irrigation facilities based on the surveyed results of the activities of irrigation fraternities in Chungnam Province. The findings and proposals for the successful unified and mono O & M system of the irrigation facilities are as follows: (1) Total number of irrigation facilities in the nation accounts for 67,582, while the total length of irrigation and drainage canals amounted to about 174,259km. On account of the total length of structural canals was estimated at 31%, much losses of water and much O & M costs have been inevitable for the full irrigation rice culture. In spite of the past heavy investment for irrigation facilities, the ratio of rain-fed and partially irrigated paddy fields accounts for 23% in 2003. Both Korea Agricultural and Rural Infrastructure Corporation (KARICO) and the city and Gun Governments have managed the irrigation facilities separately by irrigation fraternities. The KARICO have commanded 59% of irrigation paddy area with 18% of the total irrigation facilities, while the city and Gun governments covered 41% of irrigation paddy area with 82% of the existing number of irrigation facilities representing small and medium scale. (2) The 1999 demand prices of irrigation water per ton expressed in 2000 constant market price was estimated at 388 won, the supply price was amounted to 184 won per ton. Considering the supply and demand curve of the irrigation water, the existing irrigation facilities could not satisfy the demand of irrigation water. (3) In 1999, total present added value of the irrigation facilities during the economic life accounted for 48 trillion won, while total supply cost was 44.7 trillion won. The marginal benefit and cost ratio of irrigation water was 1.08. (4) The total O & M cost per year amounting to 681.1 billion won have been required to maintain and repair the existing irrigation facilities in Korea. For the successful unified O & M of irrigation facilities covering whole irrigated paddy field in Korea, 950 billion won of O & M costs are required to keep up the marginal benefit of irrigation water as 2,800 billion won per year. The total O & M cost as 950 billion won should be allocated 40%, 380 billion won for O & M costs of irrigation facilities and 60%, 570 billion won for improvement of irrigation facilities. (5) The study investigated and reviewed the present O & M status of the irrigation facilities by small and medium irrigation fraternities. Most of the farmers belong to the irrigation fraternities preferred not only unified O & M but also KARICO take-over of the whole O & M activities of the irrigation facilities. The prevailing O & M cost per 10a expended by the Corporation was amounted to 104,890 won, while that of city and Gun governments was only amounted to 4,600 won per 10a. regarding the small amount of O & M cost expended by city and Gun governments, it is evident that the existing irrigation system have been managed ineffectively and deteriorated the facilities comparing that of KARICO. In conclusion, the Government could not satisfied the demand of irrigation water by suppling water with existing irrigation facilities. Therefore new additional investment and financial support for irrigation water development should be made to convert rain-fed and partially irrigated paddy fields into fully irrigated ones. The operation and maintenance cost should be supported to keep the marginal values of rice production of existing irrigation facilities in the national economy and to modernize the obsolete irrigation facilities. By unifying the existing dual O & M systems, all the farmers belong to the irrigated paddy fields have to be equally benefited and could be increased their farm income and be stabilized their rural lives.

• 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).