• Korea Trade Review
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• v.45 no.3
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• pp.1-19
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• 2020

Recently, traditional trade in the global trade market has stagnated in the aftermath of the US-China trade war and the coronavirus (COVID-19) pandemic. However, the global e-commerce market is growing rapidly, presenting a new opportunity for exports. To examine the effect of an online matching and logistics system on reverse overseas direct purchase and the mediating effect of reliability, this study conducted a questionnaire survey on 320 employees in a Korean trade company from March 10 to April 30, 2018. The study model's goodness of fit was tested, and an analysis was performed using the AMOS statistical package. The online matching and logistics system were found to have a positive effect on reverse overseas direct purchase. Furthermore, results revealed that while a country's reliability mediated online matching and reverse overseas direct purchase, it did not mediate the logistics system. These results mean that online matching is affected by a country's reliability in overseas consumers' buying decision process. This study provides implications for the future directions of export companies and national policies to promote reverse overseas direct purchase. Future research including more countries and companies would be able to make further contributions toward the development of the Korean cross-border e-commerce industry.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.3
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• pp.224-234
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• 2016

This study developed the conductivity pattern of solid surface using laser direct pattern and compound polymer material technology. For development direct patterning system of solid surface, we used the laser power stabilizer, the dynamic focusing, 3D scanner S/W and the auto aligning techniques. Also For conductivity pattern, we are developed compound polymer material with additive by electro-less plating. These technologies are already used commercially. However operation and control integrated system for direct patterning of solid surface are not yet developed. The objective of this paper is to introduce the laser direct structuring for simple process improvement instead complex PCB process, and develop the operating stability and integration system. Also we implemented new application of laser direct structuring through sample manufacture.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.6
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• pp.403-407
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• 2018

This study proposes a predictive direct power control method in a modular multilevel converter (MMC) high-voltage direct-current (HVDC) system. The conventional proportional integral (PI)-based control method uses a cascaded connection and requires an optimal gain selection procedure and additional decoupling scheme. However, the proposed control method has a simple structure for active/reactive power control due to the direct power control scheme and exhibits a fast dynamic response by predicting the future status of system variables and considering time delay. The effectiveness of the proposed method is verified by simulation results.

• The Journal of the Korea Contents Association
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• v.5 no.1
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• pp.217-227
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• 2005

In this paper, we present the result of an efficient implementation of DirectX-based multichannel visual monitoring system and the performance analysis of it. Our proposed system mainly consists of three subsystems: display, storage, and retrieval/playback. The display subsystem is designed to utilize efficiently H/W acceleration, overlay and flip of DirectX for faster real-time display, display synchronization among channels, and improvement of tearing artifact. For the performance improvement of storage speed, the storage subsystem is designed and implemented in DirectShow Filter-based multithreading architecture so that it can store multichannel video streams efficiently in each channel with minimizing data bottleneck among channels. In the retrieval and playback subsystem, efficient index file architecture and video data storage architecture, efficient playback architecture which can make playback be processed parallel among channels are designed and implemented for faster retrieval and playback,. Through experiments, our proposed system is shown to be maximally 2 times as fast in storaging speed and maximally 3.5 times as fast in retrieval and playback speed as the previous system.

• Journal of Integrative Natural Science
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• v.9 no.1
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• pp.67-71
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• 2016

The university president direct election system in Korea had begun in 1987 as a movement of college democratization in the 1980s after 6.29 Declaration. Since then, many national/private universities had adopted the election system. However, it has posed many problems and it caused a sharp division of opinions between those who approve and disapprove the direct election system. Since 2005, the government has made official of the reformation and/or abolition of the university president direct election system, and has kept pushing for universities to give up the direct election system. Now, only 3 or 4 universities hold on to the system, and many universities have changed into the indirect election system. In the indirect election, a key is the composition of president nomination committee, which confirms the university members's variety. Many universities adopting the indirect election system have used simple random sampling, like drawing lots, to compose the president nomination committee. However, drawing lots has a problem that it has large possibility of composing a biased committee. This research suggests systematic sampling as an alternative to drawing lots. A numerical analysis was conducted using a data of a university in which the indirect election was implemented recently. The drawing lots gave the biased nomination committee. On the other hand, the systematic sample improves the problem and confirms more the variety of all members.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.2198-2204
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• 2003

In order to make a match of the insufficient direct solar radiation, in this study, the target output is lowered to 9 kW smaller than 25 kW in former studies. It is also necessary to match the collector/receiver with engine/generator systems to accomplish the power level of a system. The simulation analyses of a dish solar power system with stirling engine are totally carried out to predict the system performance with the designed values. In addition, an influence of direct solar radiation on system performance and operation control is discussed in simulation. It is found that the diameter of concentrator could be made small to 8 m regardless of slope errors with 2.5 and 5.0 mrad radiation, and the operation range of mean pressure control. is wide even if the direct solar radiation is a quit low.

• The Journal of Information Systems
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• v.12 no.1
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• pp.47-66
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• 2003

This study was examined the relationship between the exogenous and endogenous variables in our model to measure ERP system performance using path analysis. The exogenous variables are system quality, user participation, user training, top management support and self-efficacy, and the endogenous variables are system usage, user satisfaction, and work efficiency. The results of the study are shown as follows. First, all the exogenous variables in our model have a direct effect on user satisfaction, and system quality, training, and self-efficacy have a direct effect on system usage. Second, system usage has a direct effect on user satisfaction and user satisfaction has a direct effect on work efficiency. The findings show that the exogenous variables in the model are important to increase ERP implementation success.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.281-284
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• 2004

This paper presents the design and implementation of a QoS based enhanced collaboration system in MDO. This is an efficient distributed communication tool between designers. It supports text communication, audio/video communication, file transfer and XML data sending/receiving. Specially, this system supports a dynamic QoS self-adaptation by using the improved direct adjustment algorithm (DAA+). The original direct adjustment algorithm adjusts the transmission rate according to the congestion level of the network, based on the end to end real time transport protocol (RTP), and controls the transmission rate by using the information of loss ratio in real time transport control protocol (RTCP). But the direct adjustment algorithm does not consider when the RTCP packets are lost. We suggest an improved direct adjustment algorithm to solve this problem. We apply our improved direct adjustment algorithm to our of QoS (Quality of Service) [1] based collaboration system and show the improved performance of transmission rate and loss ratio.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.12
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• pp.2926-2934
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• 2000

This study presents a direct adaptive controller which is derived by using Lyapunovs direct methods for trajectory tracking control of a pneumatic cylinder. The structure of the controller is very simple and computationally efficient because it does not use either the dynamic model or the parameter values of the pneumatic system. The bounded stability of the system is shown in the presence of the bounded unmodeled dynamics. The bounded size of tracking errors can be made arbitrarily small without giving andy influences on either input or output variables. The trajectory tracking performance and the stability of the control system is verified experimentally. The results of the experiments show that the proposed controller tracks the given trajectories, sine function and cycloidal function trajectories, more accurately than PD controller does, and it stabilizes the system and adaptive variables.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.4
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• pp.474-483
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• 1996

In this paper, as a part of the method improving stability, the load-flow calculation in D.C. power system and the models for stability analysis are studied with A.C-D.C. interconnected power systems transmission performed. Moreover, the theory is established in relation to each control method of D.C. power systems. Then the stability of A.C-D.C.interconnected power systems is compared and considered by the way of dividing the operating control method of the rectifier inverter converter into ACR-AVR, APR-A.gamma.R, A.alpha.R-ACR. The dynamics characteristic of terminal voltage, frequency, active-reactive power and rotor angle of the generator with disturbances and load fluctuations is considered. In addition, the characteristic of direct voltage, direct current, power and control systems. From this the comparative analysis of the direct current control method, the possibility of the stability analysis of A.C.-D.C. interconnected power system is considered. (author). refs., figs., tabs.