• Journal of Power Electronics
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• v.15 no.1
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• pp.18-30
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• 2015

This paper focuses on a systematical and in-depth analysis of the reactive power and soft-switching regions of Dual Active Bridge (DAB) converters with dual-phase-shift (DPS) control to achieve high efficiency in a wide operating range. The key features of the DPS operating modes are characterized and verified by analytical calculation and experimental tests. The mathematical expressions of the reactive power are derived and the reductions of the reactive power are illustrated with respect to a wide range of output power and voltage conversion ratios. The ZVS soft-switching boundary of the DPS is presented and one more leg with ZVS capability is achieved compared with the CPS control. With the selection of the optimal operating mode, the optimal phase-shift pair is determined by performance indices, which include the minimum peak or rms inductor current. All of the theoretical analysis and optimizations are verified by experimental tests. The experimental results with the DPS demonstrate the efficiency improvement for different load conditions and voltage conversion ratios.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.6
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• pp.520-528
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• 2006

In this paper, we proposed the electric circuit using one common arm of H-Bridge Inverters to reduce the number of switching component in multi-level inverter combined with H-Bridge Inverters and Transformers. and furthermore we suggested the new multi-level PWM inverter using PWM level to reduce THD(Total Harmonic Distortion). and we used the phase-shift switching method that can be same rate of usage at each transformer. Also, we tested the proposed prototype 9-level inverter to clarify the proposed electric circuit and reasonableness of control signal for the proposed multi-level PWM inverter.

• Journal of Contemporary Eastern Asia
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• v.10 no.1
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• pp.55-71
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• 2011

China has been experiencing high economic growth along with massive change in its industrial structure. How will the industrial structure change affect the Chinese economy? Similar changes were observed by Japan, when the Japanese banking system fell into a structural failure in terms of the inability to respond to the paradigm shift from "catching up" to "frontier economy." This paper is undertaken to highlight the lessons that China can learn from Japan's prolonged financial slump. We point out that big cities in China have already shifted to frontier economy and major provinces are on the same trend. We argue that in spite of economic reform reshaping the Chinese banking system, the financing pattern of state owned commercial banks (SOCB) is not in line with the industrial change. The Chinese banking system should be overhauled or transformed to respond to the increasing uncertainty along with the paradigm shift. Otherwise, China may fall into the same dilemma that Japan had faced in its industrial structure change.

• Journal of Information Technology Services
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• v.20 no.5
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• pp.55-71
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• 2021

Technostress management is increasingly getting important as ICT advances and infiltrates every job and task. Especially with the advent of COVID-19, workers had to switch to teleworking utilizing ICT extensively. In this study, we developed a research model explaining antecedents and their impacts on technostress in telecommuting context, especially under the COVID-19 situation. The result revealed that techno-complexity, techno-invasion, and techno-overload are the dominant factors that affect the negative psychological responses in the COVID-19 situation. Among them, we found that techno-overload maintain the most significant influence. It is due to the lack of instant feedback on workload allocations in telework and the lack of adjustment period with the sudden shift to telecommuting. In the case of techno-complexity, employees seem to experience difficulty acquiring new technical skills. Finally, the techno-invasion came out significant, signifying the infiltration of working space by home-related activities. The emotion-focused coping strategy had a moderating effect. In contrast, the problem-focused coping strategy had no significant effect, indicating that an appropriate emotional coping strategy is more important for workers undergoing extreme changes in the work environment. Subsequently, practical and theoretical implications, limitations, and future research directions are discussed.

• The Journal of the Korea Contents Association
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• v.21 no.8
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• pp.184-200
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• 2021

This study proposes to secure the necessity and possibility of creating a footwear-only district utilizing the Kaesong Industrial Complex, a special economic zone in the North Korea. This is a policy proposal to explore strategic values for revitalizing the Korean footwear industry through a win-win cooperation model between the South and North Korea. With SWOT-AHP analysis method, we are planning to establish a strategy to utilize the footwear-only complex in Kaesong Industrial Complex for sustainability of the footwear industry. It presents a direction to overcome the industrial structural problems that the domestic footwear industry is facing with the aspect of the possibility of inter-Korea cooperation. As a result of the analysis, the 'SO strategy' is a proposal to establish inter-Korea cooperation K-shoe belt through footwear clusters in the two Koreas. The 'WO strategy' is an internationalization strategy of the Kaesong footwear-only complex. The 'ST strategy' is the use of flexible governance in the creation of a footwear-only complex for the relief of sanctions against North Korea. The 'WT strategy' is a paradigm shift in the perception of the peace economy in the footwear industry of inter-Korea for the re-opening of the Kaesong Industrial Complex.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2193-2195
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• 2001

This paper proposes test strategy detecting the faulted digital device or the faulted digital circuit on the digital circuit board using signature analysis technique based on the polynoimal division theory. SSA(serial Signature Analysis) identifies the faults by comparing the reminder from good device and reminder from the tested device, which reminder is obtained by enforcing the data stream outputed from output pins of tested device on LFSR(Linear Feedback Shift Resister) representing the characteristic equation.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2004.05a
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• pp.77-83
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• 2004

Apartment Building remodeling market is now growing centering around non housing building. Unlike non housing building remodeling business, understanding of remodeling demanders accustomed to profit of reconstruction, deficiency of experience performing remodeling project and construction, shortage of will performing remodeling policy and detailed action method are difficulties in performing apartment building remodeling business. Understanding change of remodeling demanders, strong economic incentive by government, construction management paradigm shift from new construction into building life cycle, application of construction method using existing building condition before remodeling and remodeling related industry infrastructure are required to improve this remodeling business circumstances.

• 한국경영정보학회:학술대회논문집
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• 2008.06a
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• pp.1023-1028
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• 2008

Recently the advent of web 2.0 era is an important trend in the business environmental change. Web 2.0 era means users' active participation, share, and openness, develop 'Internet penetration into everyday life,' and change many aspects of our society. web 2.0 has been making these following changes in the socioeconomic aspects: 1) acceleration of system shift to a small quantity of multi-species production system 2) growing influence of on-line channel/information to consumers 3) various minorities' power increase in the socioeconomic sector. Web 2.0 has been making these following changes in the firms' strategies for information management: 1) increase of external knowledge and information utilization 2) amplification and reproduction of information from customers 3) change of information distribution: pursuit of two-way communication with customers 4) integration of different information/services for business transformation. Firms must squarely look at socioeconomic changes owing to web 2.0, and utilize them for firms' effective information management.

• Proceedings of the Technology Innovation Conference
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• 1997.07a
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• pp.175-194
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• 1997

The competitive power of technologies is required for survival of enterprises in the social environments that change rapidly. So the strategy of technology development becomes more and more important. For the establishment of strategy, the situational analysis and the forecasting analysis are executed and they include the technology assessment and the technological forecasting. The technology assessment is systematical examination and analysis of the present status of technology. Among the various methods of technology assessment, Matrix Method is one of the usual methods. This research is intended to find out the problems and the difficulties in the current Matrix Method, and to improve the method, finally to help the R&D departments of enterprises applying the method. This suggested matrix(TSM Technology Shift Matrix) method is designed so that one can judge the current situation of technology and future expectation, by moving the matrix which is placed to the upside of the basic matrix.

• Journal of Power Electronics
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• v.14 no.6
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• pp.1224-1232
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• 2014

A full-bridge secondary dual-resonant DC-DC converter using the asymmetrical pulse-width modulated (APWM) strategy is proposed in this paper. The proposed converter achieves zero-voltage switching for the power switches and zero-current switching for the rectifier diodes in the whole load range without the help of any auxiliary circuit. Given the use of the APWM strategy, a circulating current that exists in a traditional phase-shift full-bridge converter is eliminated. The voltage stress of secondary rectifier diodes in the proposed converter is also clamped to the output voltage. Thus, the existing voltage oscillation of diodes in traditional PSFB converters is eliminated. This paper presents the circuit configuration of the proposed converter and analyzes its operating principle. Experimental results of a 1 kW 385 V/48 V prototype are presented to verify the analysis results of the proposed converter.