• Journal of Biosystems Engineering
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• v.40 no.3
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• pp.186-192
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• 2015

Background: Various solar energy collecting systems have been developed and analyzed for agricultural applications. They include solar thermal and electric devices such as solar crop dryers, solar water pumps, solar greenhouse heating, ventilation for livestock, solar aeration pumps, solar electricity, and many more. Purpose: This review provides the current status of research and development in the field as well as the solar energy systems that are currently in use in the agriculture sector across the globe. Review: Solar energy is the largest and cheapest energy resource on earth; one hour of solar radiation exceeds the complete global energy consumption in one year. The potential annual total solar radiation in South Korea is $3.58-5.4 kWh/m^2/day$. The available solar energy is sufficient for agricultural applications across the entire country. Conclusion: The scope of solar energy utilization in agricultural machinery engineering in South Korea and in other countries is promising.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.214-219
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• 2008

In this study, medium capacity EHP and GHP for air-conditioning a building with a floor area of $1,200\;m^2$ are compared economically. To consider all the factors of initial and operation costs effectively, an annual equal payment method is proposed. For the initial cost, equipment, construction, installation, electric facility, financial subsidy and tax cut are considered. Basic electricity, energy(electricity and gas), space charge, labor, insurance and repair are considered for the operation cost. Under the assumptions made in this study, overall cost of EHP is less than that of GHP. However, different outcome may result if different assumptions are made. This study is useful for performing an economic evaluation of various air-conditioning systems.

• Management & Information Systems Review
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• v.20
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• pp.61-83
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• 2007

This study estimates gender wage gap by the Korean industries. The empirical findings are as follows: 1. The sex segregation by industries has not improved. 2. The average wage in $\ulcorner$electricity, transportation, warehousing, financial institutions$\lrcorner$ is relatively higher than others. On the contrary, the average wage in $\ulcorner$mining and manufacturing$\lrcorner$ and $\ulcorner$wholesale and retail, food, loading$\lrcorner$ is relatively lower than others. 3. The gender wage gap in $\ulcorner$electricity, transportation, warehousing, financial institutions$\lrcorner$ is relatively lower than others. On the contrary, the gender wage gap in $\ulcorner$mining and manufacturing$\lrcorner$ is relatively higher than others. The gender wage gap has declined annually. The gender wage gap in industries with lower wage level is higher. The decline of gender wage gap cannot be interpreted as a relaxation of sexual discrimination.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.11
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• pp.948-953
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• 2002

The electric power load during the peak time in summer is strongly affected by cooling load, which decreases the preparation ratio of electricity and brings about the failure in the supply of electricity in the electric power system. The ice-storage system and heat pump system are possible solutions to settle this problem. In this study. the method of estimating temperature and humidity to forecast the cooling load of ice-storage system is suggested, then the method of forecasting the cooling load using fuzzy logic is suggested by simulating that the cooling load is calculated using actual temperature and humidity. The forecast of the temperature, humidity and cooling load are simulated, and it is shown that the forecasted data approach to the actual data. Operating the ice-storage system by the forecast of cooling load with night electric power will improve the ice-storage system efficiency and reduce the peak electric power load during the summer season as a result.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.12
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• pp.549-555
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• 2001

Due to the development of information technology, the operating power systems under the deregulated environment has the advantages of a introduction of the market function, a competition in sales and purchases of Power, as well as the difficulty of maintaining reliability on the same or high level with it in a monopolistic market. This paper presents a basic scheme of the congestion management in the Korea electricity market under the deregulated environment. We investigated some cases of the congestion management in the world and the effects of the congestion management in the power systems. A basic idea of the congestion management in the Korea is presented based on the analysis of transmission congestion management in the competitive electricity market.

• Journal of Aerospace System Engineering
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• v.15 no.4
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• pp.47-56
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• 2021

In the management of aged aircraft, used avionics equipment is replaced with new ones to improve the performance and extend the life cycle of the aircraft. In this case, considering airworthiness, it is necessary to check whether the aircraft has sufficient electricity in the electric generator or the electrical distribution system, in accordance with the maximum electricity consumption of the new avionics equipment. Accordingly, this paper reviews a few airworthiness standards and guidelines associated with the electrical load analysis when an avionics equipment is upgraded in an aged aircraft, and proposes an optimization method for the electrical load analysis. In addition, it verifies the validity of the proposed method via the QFD theory, and is currently available for upgrading the performance of aged aircraft.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.1
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• pp.111-119
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• 2022

This paper is about power transfer between heterogeneous systems in zero-energy buildings. Currently, electricity used in buildings, from renewable energy generation power in buildings, consists of alternating current networks. In order to use electricity, alternating current must be converted to direct current, which typically results in a loss of 10%. In order to solve this problem, research is needed to reduce power loss as much as possible by implementing both a DC network and an AC network in a zero-energy building. Therefore, in this paper, an inter-link converter capable of bidirectional power transfer between DC and AC networks applied to zero-energy buildings is developed. The structure of the inter-link converter to be developed was proposed and its feasibility was verified through simulations and experiments.

• KIEAE Journal
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• v.15 no.2
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• pp.95-101
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• 2015

Purpose: A photovoltaic/thermal system is a solar collector combining photovoltaic module with a solar thermal collector, which produces electricity and heat at the same time. PVT system removes heat from PV module through air or liquid that would help to raise the efficiency of the PV systems performance. Many innovative systems and products have been put forward and their quality evaluated by academics and professionals. However, even though various of PVT system were developed and several systems were applied to practical use, there have been few researches for the performance analysis using the dynamic simulation. Method: In this study, the review of recent research and development trend for PVT systems were conducted. Furthermore, in order to develop the optimum design method, the performance analysis for PVT system was conducted by a dynamic simulation. Result: In the results, it was found that the performance of PVT system significantly depends on the ambient temperature and solar radiation. Moreover, in the weather condition of Seoul, average efficiency of electricity and heat in heating season were 13.79 and 41.85%, and they in cooling season were 14.39% and 26.18%, respectively.

• KIEAE Journal
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• v.13 no.6
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• pp.39-44
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• 2013

As the use of electric vehicles perspectively increases, infrastructures for charging car batteries need to be properly planned for satisfying new requirements. This study aimed at theoretically investigating the relative laws, size of existing parking lots, and diverse car sizes for suggesting parking places for electric vehicles. In addition, potential problems for changing existing parking lots to new parking lots for electric vehicles were thoroughly considered. Based on the problem recognition, the feasibility, in particular, of the change of existing parking place to new place equipped with electricity charging systems was investigated. The comprehensive reviews and surveys revealed that additional systems for charging electricity need to be developed to be suspended on the ceiling for existing parking lots in order to prevent changing current layout of the space. This system will alleviate the perspective problems when the charging systems are located on the floor such as contamination, electric shock, and damage by cars. Further study will be followed for testing performance of the suggested systems in the actual parking lots.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.5
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• pp.351-360
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• 2016

Rapid population growth with high living standards and high electronics use for personal comfort has raised the electricity demand exponentially. To fulfill this elevated demand, conventional energy sources are shifting towards low production cost and long term usable alternative energy sources. Hybrid renewable energy systems (HRES) are becoming popular as stand-alone power systems for providing electricity in remote areas due to advancement in renewable energy technologies and subsequent rise in prices of petroleum products. Wind and solar power are considered feasible replacement to fossil fuels as the prediction of the fuel shortage in the near future, forced all operators involved in energy production to explore this new and clean source of power. Presented paper proposes fuzzy logic based Energy Management System (EMS) for Wind Turbine (WT), Photo Voltaic (PV) and Diesel Generator (DG) hybrid micro-grid configuration. Battery backup system is introduced for worst environmental conditions or high load demands. Dump load along with dump load controller is implemented for over voltage and over speed protection. Fuzzy logic based supervisory control system performs the power flow control between different scenarios such as battery charging, battery backup, dump load activation and DG backup in most intellectual way.