• The Journal of Asian Finance, Economics and Business
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• v.5 no.2
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• pp.5-14
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• 2018

This study is motivated based on concern from some renowned scholars and central bankers whom have raised the issue of the sustainability of the International Monetary System (IMS). Using the panel data set of four major international currencies, USD, JPY, EUR and GBP from 1973 to 2013 with Pooled Mean Group (PMG) estimator, to re-examine whether Triffin dilemma still exists through investigating the relationship between the reserve share, current account balance and real effective exchange rate. The evidence from the result indicates that Triffin dilemma exists only in the long run, and shows that in the long-run, current account balance is proportionate to the increased real effective exchange rate while varies inversely with the reserve shares. However, the estimation for the short-run is not significant to prove the existence of Triffin dilemma. In addition, we investigated the non-dollar panel sample and found that the international monetary system still suffers from Triffin dilemma even without the dollar. To overcome Triffin dilemma, immediate step such as having currency swap mechanism is recommended. In medium term, a multi-polar Monetary System is suggested, and in the longer time, a supranational currency will be used to replace all the currencies in the world.

• Journal of Environmental Health Sciences
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• v.40 no.2
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• pp.71-80
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• 2014

Objectives: The main purpose of this review is to introduce the current status of environmental health indicators of Korea and to share our experience of the developmental process of Korean version of environmental health indicators. Methods: This paper describes 1) the background of environmental health indicators; 2) the ways how we developed environmental health indicators of Korea; 3) the current status of selected indicators; and 4) suggestions for the further policy development. Results: The 6-year long project for the development of environmental health indicator systems in Korea could provide outputs on three major distinct aspects on the indicator issues. Firstly, we have developed the rational process/manual so that the government can select and advocate the potential indicators with a relatively objective manner. Secondly, we have suggested the potential candidate indicators which can be implemented immediately. We also pooled all indicators in order to evaluate the summary index which we expect to tell the status of environmental health. Third, we provided suggestions on the further utilization of this indicator system. Conclusion: The mission of environmental health policy is to resolve the public health problems occurring because of hazardous environment. In order to identify the environmental determinants of the community health problems and to evaluate the effectiveness of the policy implemented, these environmental indicators can be used. Therefore, the government should implement this ready-prepared system of environmental health indicators.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.652-654
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• 2015

Integrated switched reluctance motor drive as an electric vehicle battery charger is presented in this paper. The SRM, which is used as the traction power in the driving mode, is used in the charge circuit to improve the power factor of charging system. The charging circuit can share the power switches of the asymmetric converter and phase windings of SRM to charge the battery, and can reduce the size and cost of the system in the plug-in system. To keep the rotor at standstill, zero torque control method is proposed. Since the inductances of the SRM windings are not same at any stop position, the charger controller controls the reference current to satisfy the total charging current with PFC and zero torque condition. A novel cubic equation method is proposed as a current reference distributor of the charging controller. Simulations are performed by MATLAB software and results satisfy the Effectiveness of proposed battery charging system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.3
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• pp.74-80
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• 2004

If the withdrawal force of strand driven roll which is controlled with predetermined speed isn't distributed regularly in continuous casting process, mold level is changed cyclically and slab quality is not good. In this paper, both casting speed control and load sharing control algorithm of strand driven roll according to ratio which is set up by operator at same time is proposed. The proposed algorithm is to share the withdrawal force by following torque current of each driven roll as average torque current by changing speed reference of each driven roll motor. The load sharing control with anti-wind up for improvement transient state is adopted and the proposed algorithm is implemented in POSCO pilot caster.

• Journal of Power Electronics
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• v.11 no.4
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• pp.533-541
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• 2011

The redundant operation of a parallel AC to DC converter via a serial communication bus is presented. The proposed system consists of three isolated CUK power factor correction modules. The controller for each converter is a dsPIC30F6010 microcontroller while a RS485 communication bus and the clock signal are used for synchronizing the data communication. The control strategy of the redundant operation relies on the communication of information among each of the modules, which communicate via a RS485 serial bus. This information is received from the communication checks of the converter module connected to the system to share the load current. Performance evaluations were conducted through experimentation on a three-module parallel-connected prototype, with a 578W load and a -48V dc output voltage. The proposed system has achieved the following: the current sharing is quite good, both the transient response and the steady state. The converter modules can perform the current sharing immediately, when a fault is found in another converter module. In addition, the transient response occurs in the system, and the output voltages are at their minimum overshoot and undershoot. Finally, the proposed system has a relatively simple implementation for the redundant operation.

• Journal of Power Electronics
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• v.11 no.4
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• pp.499-506
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• 2011

This paper presents an interleaved active-clamping zero-voltage-switching (ZVS) forward-flyback converter without an output choke. The presented topology has two active-clamping circuits with two separated transformers. Because of the interleaved operation of the converter, the output current ripple will be reduced. The proposed converter can approximately share the total load current between the two secondaries. Therefore, the transformer copper loss and the rectifier diodes conduction loss can be decreased. The output capacitor is made of two series capacitors which reduces the peak reverse voltage of the rectifier diodes. The circuit has no output inductor and few semiconductor elements, such that the adopted circuit has a simpler structure, a lower cost and is suitable for high power density applications. A detailed analysis and the design of this new converter are described. A prototype converter has been implemented and experimental results have been recorded with an ac input voltage of 85-135Vrms, an output voltage of 12V and an output current of 16A.

• Current Photovoltaic Research
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• v.6 no.1
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• pp.1-11
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• 2018

Current major photovoltaic (PV) market share (> 60%) is being occupied by the multicrystalline (mc)-silicon solar cells despite of low efficiency compared to single crystalline silicon solar cells. The diamond wire sawing technology reduces the production cost of crystalline silicon solar cells, it increases the optical loss for the existing mc-silicon solar cells and hence its efficiency is low in the current mass production line. To overcome the optical loss in the mc-crystalline silicon, caused by the diamond wire sawing, next generation texturing process is being investigated by various research groups for the PV industry. In this review, the limitation of surface structure and optical loss due to the reflectivity of conventional mc-silicon solar cells are explained by the typical texturing mechanism. Various texturing technologies that could minimize the optical loss of mc-silicon solar cells are explained. Finally, next generation texturing technology to survive in the fierce cost competition of photovoltaic market is discussed.

• The Journal of Asian Finance, Economics and Business
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• v.5 no.1
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• pp.53-62
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• 2018

The study aims to conduct organizational diagnosis at Infosys and to suggest measures of improvement of the same wherever necessary. Data was collected with the help of a structured questionnaire. Respondents were selected with the help of random sampling technique. The sample size is 19. The employees are not much clear about their goals and the purpose of the organization. The employees are not satisfied with the current structure and the division of the work in the organization, and also with the current reward mechanism of the organization. However the employees are satisfied with their leaders and their leadership styles. The employees feel that they share a good relationship with their peers. The employees of Infosys have full confidence in the management and they believe that the management is helping them in their career growth. Some of the interventions suggested are as follows: Role Analysis Technique can be used so that the employees get clarity of their goals. As the score suggests that the employees are not happy with the current structure and distribution of the work, mentors can be assigned to the employees who can guide them and can also help the employees to understand the structure and processes better.

• Journal of Power Electronics
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• v.14 no.5
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• pp.882-889
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• 2014

This paper presents a zero voltage switching (ZVS) converter with three resonant tanks. The main advantages of the proposed converter are its ability to reduce the switching losses on the power semiconductors, decrease the current stress of the passive components at the primary side, and reduce the transformer secondary windings. Three resonant converters with the same power switches are adopted at the low voltage side to reduce the current rating on the transformer windings. Using a series-connection of the transformer secondary windings, the primary side currents of the three resonant circuits are balanced to share the load power. As a result, the size of both the transformer core and the bobbin are reduced. Based on the circuit characteristics of the resonant converter, the power switches are turned on at ZVS. The rectifier diodes can be turned off at zero current switching (ZCS) if the switching frequency is less than the series resonant frequency. Therefore, the reverse recovery losses on the rectifier diodes are overcome. Experiments with a 1.6kW prototype are presented to verify the effectiveness of the proposed converter.

• Journal of the Korean Institute of Educational Facilities
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• v.27 no.2
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• pp.57-68
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• 2020

This research aims analyze the current situation and problems of cultural heritage education, and propose the methodology of cultural heritage education and the model of the curriculum for each education subject. This study consists of three parts. First, the current status of education related to cultural heritage was examined separately by general public, university and graduate students, and practitioners. Second, we reviewed the National Competency Standard(NCS) and the UNESCO World Heritage Competency Framework(CF) as a way to solve the problem of cultural heritage education for each education subject. By examining the methodology and curriculum model of cultural heritage education, we tried to find the future direction of cultural heritage education. Third, the education model of the cultural heritage curriculum for each educational subject was proposed by reflecting the direction and the cyclical education model of sustainable cultural heritage education. In future studies, we intend to use the education model presented in this study to specifically propose basic guidelines for the cultural heritage convergence curriculum.