• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.8
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• pp.1347-1354
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• 2016

This paper presents optimal operational scheduling model and economic assessment of Li-ion battery energy storage systems installed in non-residential customers. The operation schedule of a BESS is determined to minimize electric bill, which is composed of demand and energy charges. Dynamic programming is introduced to solve the nonlinear optimization problem. Based on the optimal operation schedule result, the economics of a BESS are evaluated in the investor and the social perspective respectively. Calculated benefits in the investor or customer perspective are the savings of demand charge, energy charge, and related taxes. The social benefits include fuel cost savings of generating units, construction deferral effects of the generation capacity and T&D infra, and incremental CO2 emission cost impacts, etc. Case studies are applied to an large industrial customer that shows similarly repeated load patterns according to days of the week.

• Journal of the Korea Society of Computer and Information
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• v.24 no.3
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• pp.29-39
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• 2019

In this study, we introduce a model that satisfies energy efficiency and economical efficiency by introducing and demonstrating cogeneration generators in industrial complexes using various actual data collected at the site. The proposed model is composed of three scenarios, ie, full - time operation, scenario operated according to demand, and a fusion type. In this study, the power generation profit and surplus thermal energy are measured according to the operation of the generator, and the thermal energy is traded according to the demand of the customer to calculate the profit and loss including the heat and evaluate the economic efficiency. As a result of the study, it is relatively profitable to reduce the generation of the generator under the condition that the electricity rate is low and the gas rate is high, while the basic charge is not increased. On the contrary, if the electricity rate is high and the gas rate is low, The more you start up, the more profit you can see. These results show that even a cogeneration power plant with a low economic efficiency due to a low "spark spread" has sufficient economic value if it can sell more than a certain amount of heat energy from a nearby customer and adjust the applied power through peak management.

• Journal of the Korea Society of Computer and Information
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• v.21 no.6
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• pp.117-125
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• 2016

In this research, economic analysis of Integrated Information System for Nano-convergence Industy (hereafter 'NANOIN'), which was developed and has been in operation by Organization of Nano-convergence Industrial Cooperation, is conducted. For this purpose, the research has been carried out in the following order. First, NANOIN user's maximum willingness-to-pay is estimated using contingent valuation method, the number for NANOIN users is estimated using Bass Diffusion Model, and annual benefit from NANOIN is estimated. Next, annual cost from NANOIN is estimated using annual budget for NANOIN related planned activities. Finally, economic value of NANOIN is evaluated using economic analysis applied to the estimated annual NANOIN benefit and cost. From the economic analysis, it is found that NANOIN has some economic value. It is expected that the procedures suggested in this research can help to systematically evaluate economic value for public goods which have not only uncertain benefit from user's side but also uncertain demand just like NANOIN.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.2
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• pp.158-164
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• 2018

Wind power forecast is critical for efficient power system operation. However, wind power has high forecasting errors due to uncertainty caused by the climate change. These forecasting errors can have an adverse impact on the power system operation. In order to mitigate the issues caused by the wind power forecasting error, wind power curtailment and energy storage system (ESS) can be introduced in the power system. These methods can affect the economics of wind power resources. Therefore, it is necessary to evaluate the economics of the methods for mitigating the wind power forecasting error. This paper attempts to analyze the economics of wind power curtailment and ESS operation for mitigating wind power forecasting error. Numerical simulation results are presented to show the economic impact of wind power curtailment and ESS operation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.6
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• pp.864-871
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• 2015

Recently, one of the main research on the power distribution system is the microgrid. The microgrid is a combination of power sources and loads, which is controllable and has separable connection. The main objective of microgrid is the deployment of the renewable clean energy and the enhancement of load-side reliability. The modern power sources and loads have DC I/O interfaces, which is the major advantage of DC microgrid compared to the conventional AC grid. The components in the microgrid have diverse features, so there is need of proper coordination control. For achieving economic feature, the active power of renewable energy resources is regarded as major control parameter and the whole operation modes of DC microgrid are defined, and the proper operations of each component are described. From the inherent characteristics of DC, there are two control variables: voltage and active power. Through analysis of operation modes, it is possible to determine exact control objectives and optimized voltage & power control strategy in each mode. Because of consideration of whole operation modes, regardless of the number and capacity of components, this coordination control method can be used without modification. This paper defines operation mode of DC microgrid with several DC sources and suggests economic and efficient coordinated control methods. Simulation with PSCAD proves effectiveness.

• Journal of IKEEE
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• v.23 no.3
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• pp.1027-1032
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• 2019

In this paper, we had developed an algorithm that can cope with all the economic variables that may occur in the operation of PV-ESS system by developing the algorithm for the operation method of PV-ESS connected system. Based on this, the optimal operation schedule of PV-ESS was decided to minimize the electric charges of customers. Through this, we developed a three-dimensional dynamic planning method based on case generation to determine the optimal PV-ESS operation schedule stably even when exogenous variables change.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.5
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• pp.160-170
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• 2007

This study predicts Life Cycle Cost of RC Slab bridge case in maintenance and operation level and calculated economic efficiency by the avoidable costs of a bridge. This result of the study can be summarized as follow: (1) LCC analysis model on the bridge case is suggested. (2) Maintenance and operation level of a bridge have been divided, and LCC of the bridge case has been predicted at current maintenance and operation level and required maintenance and operation level. (3) Reduction costs is predicted by LCC of the bridge case, and its economic efficiency is calculated.

• Journal of the Economic Geographical Society of Korea
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• v.21 no.1
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• pp.34-52
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• 2018

The aim of this study is to identify economic geographical determinants that affect the sustainability of the social economy. The sustainability of the social economy means the sustainability of the pursuit of social value as well as the sustainability of business operation. This study is aiming to economic geographical determinants as factors affecting sustainability of the social economy and extracted measurement index through examination on the theory and case study. As a result, 10 items in two areas(the sustainability of the pursuit of social value, the sustainability of business operation) had been deducted as the measurement index of which sustainability of the social economy. In addition, 20 items in four areas(local networks, intermediary organizations, local community culture and public roles) had been deducted as economic geographical determinants. Multiple regression analysis through 193 firm surveys suggests that 'local networks', 'intermediary organizations', and 'public roles' have an positive impact on sustainability. This result implies a need for policies to create an economic geography ecosystem of social economy.

• Journal of the Korean Dietetic Association
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• v.6 no.1
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• pp.33-43
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• 2000

Environmental pressures from such sources an economic condition, the government and inter-institutional competition create managerial challenges. Economic pressures may be forcing dietetic dept, in hospital to utilize cost∙benefit analysis to assist them in their problem solving. Cost∙benefit analysis have been widely used in business, industry and many other fields with only limited application to foodservice. Due to the lack or this information the purposes of this study were to identify use of cost∙benefit analysis in hospital foodservice system to evaluate the economic efficiency of alternatives, and to make recommendation for operation system change. Using the cost∙benefit method, cash flows are separated into cost and benefits. For an alternative to be selected, indicators, such as NPV, benefit-cost ratio (B/C ratio) with 5% discount rate per annum. The sensitivity analysis was also conducted with difference rate 3%, 7% respectively and reduced employee payroll change. The result of this study can be summarized as follows : 1. The total cost of investment for operation system change was 390,570 thousand won and the total benefit through operation system change was 865,808 thousand won. 2. Net present value(NPV) for 5 years was 475,239 thousand won and benefit-cost ratio was 2.22. 3. In sensitivity analysis with different discount rate 3%, 7%, benefit-cost ratio was 2.25, 2.18 respectively, with total reduced employee payroll change, benefit-cost ratio was 2.86. In conclusion, total benefits were exceeded total costs. Therefore, the project of operation system change in hospital foodservice was found to be economically efficient.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.06a
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• pp.173-174
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• 2009

For container shipping company, fuel oil prise is a considerable expense. In the last 3 years, fuel oil prises have risen considerably. An increasing fuel oil prise in container shipping, in the short term, is only partially compensated through surcharges and will therefore affect earnings negatively. This paper deals with the impact of increasing fuel oil price and capital costs for vessels on the number of vessels on the Asia-Europe trade. As per result of 'H' carrier's operation in 2008, there were no cost difference between 8 and 9 vessels operation in case the fuel oil price is USD 169/tons while adopt USD 31,818 as fixed cost. We can expect that the fuel oil price will not be decreased under USD 200 $/Ton on the basis of current high oil price phenomenon. When the fuel oil price is over USD 200 $/ton, therefore, 9 vessels operation is more economic than 8 vessel operation even if the fixed cost is over USD 35,000.