• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.6
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• pp.29-37
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• 2012

As the demand for the fresh non-thermal food is increased, it is required to develop the fast and perfect sterilization method. The conventional sterilization method using ultraviolet lamp has some disadvantages such as imperfect sterilization and longer process time. In this research, IPL(Intense Pulsed Light) sterilization system is introduced to overcome the drawbacks of the conventional system, and suitable power supply architecture for the system is discussed. Since the IPL sterilization system uses Zenon lamps which requires the 600~2,100[V] for the lightning and 16~30[kV] for the trigger, the converter for the system should be able to generate the high voltage and to discharge the large amount of energy instantaneously. In this research a new power system architecture which has a modified forward converter topology with two switches for generating high voltage and a capacitor bank to control the energy for the lightning by switching is introduced.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.10
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• pp.1823-1831
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• 2011

When the RPS(Renewable Portfolio Standards) becomes effective in 2012, the use of renewable energy will be dramatically increased. However, there are no production simulations and demand supply programs that reflect the characteristics of the renewable energy. This paper analyzes correlations of the domestic wind power and solar power generation pattern in different areas and those of these sources' output and load pattern. Based on the regional correlation analysis, an appropriate method that uses a average output of the renewable energy or another modeling that takes account of uncertainty could be selected. Because it's output is dependent on weather condition, we can not control the generation of renewable energy, that is the reason why the correlation between the load and output pattern of sources can be helpful to determine whether the renewable energy is modeled as a generator or load modifier. Through this analysis, a basis will be provided in order to properly model the renewable energy source.

• The Korean Journal of Health Service Management
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• v.11 no.4
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• pp.239-250
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• 2017

Objectives : The purpose of this study was to analyze the types of hospitals participating and the factors influencing comprehensive nursing service. Methods : Data were gathered from 231 hospitals offering the comprehensive nursing service in 2016. Collected data were analyzed using the multinomial logistic regression with the SPSS 24 version program. Results : First, factors influencing the types participating comprehensive nursing services were identified as hospital type, number of beds, medical doctor and, nurses per bed. Second, if all tertiary hospitals, general hospitals and hospitals participated in the service, approximately 122,022 ~ 166,274 nurses would be needed for the service. Conclusions : Hospitals providing the comprehensive nursing service will be expanded gradually. As such, thoughtful policy considerations are required to successfully establish services, such as improvement in hospitals, required nurse staffing level and demand and supply of nurses. Therefore, it is necessary to control the participation ratio of hospitals in consideration of the various circumstances.

• Journal of International Area Studies (JIAS)
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• v.15 no.1
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• pp.83-108
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• 2011

South America has vast energy resources with the renewable and non-renewable sources. However, many countries in the region are unable to guarantee adequate energy security both of energy supply and demand. Currently the possibility of energy security is high through regional energy integration based on the potential economic benefits. The difference of regulation system with the individual countries in the region impose strong barriers to integration process. Security of energy supply and its demand as well is fundamental issues in this region and regional energy cooperation is essential for getting rid of the insecurity of energy supplies. Despite of this problem, currently Latin American countries made a great effort to make multilateral energy security regime through projecting great energy infrastructure network(e.g. IIRSA) or mechanism especially in South America, which can give countries access to the region's reserve supplies by providing regulations and pricing mechanism with a shared energy market in this region. Brazil's active leading in the formulation of such movement toward energy security integration and participation of energy infrastructure network is good initiative to enforce this great energy security change. Politically and economically, Brazil's geographical position and the level of market size and oil and natural gas resources, in addition the leadership in renewable energy sources make it a sound candidate to take over the coordination of the secure integration of region's energy market. However, on the conditions of existing many obstacles such as, control of the output of the region's power plant, energy flows, the environmental matter within local community must be overcome to make more advance process and steps. Finally, to secure more institutional approach, this region must settle regional disputes resolution regime urgently.

• Journal of Labour Economics
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• v.33 no.3
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• pp.47-88
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• 2010

Focusing on the Korean experience, particularly a recent amendment which extends maternity leave and increases financial benefits during maternity and childcare leave, this paper evaluates how such an expansion of benefits affects the employment and the hourly wages of young wages of childbearing age. Empirical results from a difference--in-difference-in-differences model having older warren, older men, and young men simultaneously as the control group suggest that neither the employment nor the hourly wages of young women are affected. This implies that the law change does not cause shifts in the labor supply curve and the labor demand curve for young women.

• Korea Trade Review
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• v.44 no.3
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• pp.25-42
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• 2019

This research examined the mediation effect of Workforce Agility (WA) on the relationship between environmental uncertainty and operational performance. We manipulated the control variables that are known to be affected by employment flexibility. Employment flexibility is caused by idiosyncratic characteristics of Korean port system. The analysis was tested by Baron & Kenny's method. The result indicates that each path of the proposed model is significant. Furthermore, the mediation effect was checked with the Sobel Test. The research revealed that environment uncertainty poses an indirect effect on operational performance. Both supply/demand uncertainty and technological uncertainty affected operational performance through the mediation effect of WA. Most of the distribution centers located in Busan Newport Distripark are operated in a bimodal labor (human resource) system which includes both permanent employees (workers) and temporary employees (workers). This empirical research provides theoretical and managerial implications by suggesting ways to increase efficiency in distribution center operation through WA enhancement, and to improve the unloading labor system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.2
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• pp.321-324
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• 2022

The Korean halibut farming industry suffer from price instability and demand decrease due to various environmental and social issues. It is urgent to predict the appropriate amount of halibut production. However, it is not easy for employments working in the halibut farming industry to handle statistical tools in order to perform the prediction. In this paper, we implemented a Excel-based regression analysis tool that allows users to get a regression analysis result by just entering historical data in a sheet. Our tool will reduce workloads of employments working in the halibut farming industry by enabling them to perform a regression analysis with Excel on-the-fly. This study expect that by using the tool the halibut farming industry cope actively with the real-time change in the industry.

• Journal of the Korea Society of Computer and Information
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• v.28 no.7
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• pp.1-9
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• 2023

Currently, as the demand for stops in the urban increases resulting from an increase in the supply of express trains, the development of trains capable of operating both high-floor platforms in the urban and low-floor platforms in the suburbs is required. In this paper, we studied the design and fabrication of a controller for train doors that consists of low and high steps as a plug-in type door mechanism and thus can be used on low and high platforms. This DCU H/W was designed and implemented using 32 bit MCU to control 4 motors, 33 digital inputs and 16 digital outputs. In addition, based on the software life cycle of EN50128, 2 items of operation requirements and 12 items of control requirements were derived, and then they were designed and implemented as operation SW. The implemented SW was tested for each requirement. As a result, we performed tests on 13 items that could be tested in the mock-up out of 14 total requirement items and showed that the requirements were satisfied.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.9
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• pp.498-502
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• 1999

Harmonics and the reactive power related problems in the supply and demand side are increasing with the proliferation of nonlinear loads such as power converters in industrial applications. Filtering options such as passive, active and hybrid filters are countermeasures against these problems. In this study, a novel hybrid active filter topology with a new approach to enhance the system performance is presented. In this study, a novel hybrid active filter topology with a new approach to enhance the system performance is presented. The proposed topology comprised a parallel inverter and a hybrid active filter. It improves the system efficiency and reduces VA ratings, hence, overall filtering cost. The system operation, control and experimental verification on three phase rectifier and/or capacitor loads are presented.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.114-123
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• 2018

Recently, as one of the countermeasures to reduce carbon dioxide($CO_2$) for global warming problems, operation methods in micro-grid systems replacing diesel generator with renewable energy sources including wind power(WP) and photovoltaic(PV) system have been studied and presented in energetic manners. However, it is reported that some operation problems in micro-grid systems without diesel generator for carbon-free island are being occurred when large scaled WP systems are at start-up. To overcome these problems, this paper proposes an operation strategy in micro-grid systems by adapting control devices such as CVCF(constant voltage constant frequency) ESS(energy storage system) for constant frequency and voltage regulation, load control ESS for balancing demand and supply and SVC(static-var compensator) for reactive power compensation. From the simulation results based on the various operation scenarios, it is confirmed that the proposed operation strategy in micro-grid systems without diesel generators is a useful tool to perform a stable operation in micro-grid systems without diesel generator and also make a contribution to reduce carbon dioxide in micro-grid systems.