• Journal of Advanced Marine Engineering and Technology
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• v.24 no.6
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• pp.155-163
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• 2000

A technology of full time four wheel drive(4WD) vehicle has been improved greatly, and the market share of full time 4WD has been extended steadily in recent days. The transfer case is an essential element in the 4WD automobile. In this paper, the details of electronically controlled transfer case is described. In order to achieve easy shifting, the shifting, the developed system automate the conversion of "$4\times2\longleftrightarrow4\times4(H)\longleftrightarrow4\times4(L)$". Furthmore, this system employs an chain drive type instead of gear drive type for drive type and synchromesh type instead of constant-mesh type for gear mesh type. Therefore, the developed transfer case is accomplished light-weight, low noise, and compact.d compact.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.2
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• pp.80-86
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• 2003

In this paper, a new three-phase voltage-source inverter topology for high voltage and high Power applications is proposed to improve the quality of output voltage waveform. A chain converter which is used as an auxiliary circuit generates a ripple voltage and injects it to the conventional 12-step inverter. Thus, the injection of the ripple voltage results in 36-step operation with a link and 60-step operation with two links. The proposed inverter is compared to the conventional multilevel inverter in the viewpoint of ratings of phase- shifting transformers, switching devices and capacitors employed. The proposed scheme is simple to control capacitor voltages compared to the conventional schems and is cost effective for high voltage and high power application over several tens of MVA. The proposed approach is validated through simulation, and the experimental results are provided from a 2KVA laboratory prototype.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.6
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• pp.35-41
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• 2022

Heavy snow damage can be prevented in advance with an appropriate security system. To develop the security system, we developed a model that predicts snow depth after a few hours when the snow depth is observed, and utilized it to calculate a failure probability with various types of greenhouses and observed snow depth data. We compared the Markov chain model and Bayesian long short-term memory models with varying input data. Markov chain model showed the worst performance, and the models that used only past snow depth data outperformed the models that used other weather data with snow depth (temperature, humidity, wind speed). Also, the models that utilized 1-hour past data outperformed the models that utilized 3-hour data and 6-hour data. Finally, the Bayesian LSTM model that uses 1-hour snow depth data was selected to predict snow depth. We compared the selected model and the shifting method, which uses present data as future data without prediction, and the model outperformed the shifting method when predicting data after 11-24 hours.

• Journal of Distribution Science
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• v.22 no.3
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• pp.93-104
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• 2024

Purpose: Using green supply chain management (GSCM), the current study focuses on the fashion design industry as a central player in promoting an eco-conscious consumption culture by creating awareness of the need to produce and consume eco-friendly fashion products instead of only capitalizing on the shifting consumer tastes, preferences, and expectations. Research design, data and methodology: This study selected a PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist as a research methodology. The purpose is the detailed and disinterested evaluation of all the published information related to the topic of the research. Results: This study suggests brief solutions of the GSCM based on the five categories of sustainable fashion activities that contribute to the development of eco-friendly fashion designs and marketing strategies. This strategy employed by firms to promote sustainable production and consumption is a major factor in enhancing consumers' environmental awareness. Conclusions: The study delves into how brands in the fashion design industry provide a platform for collective action by investing in educational campaigns and transparent communication, collaborating with various stakeholders to maximize awareness of the need for eco-conscious consumption and the availability of green fashion products. Practitioners should consider developing a comprehensive framework to assess the feasibility of different awareness strategies and purchase stimulation approaches.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.4
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• pp.365-371
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• 1990

In this paper, the authors calculate GDOP(Geometric Dilution of Precision) with the mast and slave transmitting stations at the past and present and simulation positions in the 9970 chain and 5970 chain of the loran C system, and analyzed variations of the GDOP and effective ranges in accordance with the shifting of transmitting stations. The results obtained are as follows; 1) The line 3.0 of equi-GDOP map that the Z slave station of 9970 chain is Guam island is falled on with line 2.0 of it's map that it is Yap island approximately, and units of GDOP of calculating with Guam island are increased then them with Yap island on the south parts of mast station. 2) If the control right of Z slave station of 9970 chain could be not transfered to japan and be closed on account of the territorial problems, the units of GDOP to calculate without it's station at any positions are very increased and the accuracy is down on the south parts of mast station. The line 5.0 of it's map is falled on with line 2.0 in case of Yap island, its Z station, and line 3.0 in case of Guam island with Z slave station approximately. 3) The X slave station of 9970 chain and 5970 chain are required rearrangement for the purpose of accurating position fix and expending service area in view of propagation route of wave and arrangement of transmitting station.

• Journal of Advanced Navigation Technology
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• v.13 no.5
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• pp.691-698
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• 2009

Chen et al. proposed a RFID authentication protocol for anti-counterfeiting and privacy protection. A feasible security mechanism for anti-counterfeiting and privacy protection was proposed using XOR and random number shifting operations to enhance RFID tag's security providing a low cost. However, their authentication protocol has some drawbacks and security problems because they did not consider the surrounding environments. We conduct analysis on the protocol and identify problematic areas for improvement of the research. We also provide enhanced authentication and update scheme based on the comment for efficient supply chain management. The proposed protocol was analyzed and compared with typical XOR based RFID authentication protocols and it was confirmed that our protocol has high safety and low communication cost.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.6 s.348
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• pp.30-37
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• 2006

This paper presents a modified scan cell architecture to reduce the power dissipation during testing. It not only eliminates switching activities in the combinational logic during scan shifting but also reduces switching activities in the scan chain during the time. Furthermore, it limits the transitions on capture cycles. It can be made for test-per-scan BIST and employed in both single scan style and multiple scan style. Experimental results demonstrate that the proposed structure achieves the same fault coverage with lower power consumption compared to other existing BIST schemes.

• Journal of Navigation and Port Research
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• v.35 no.7
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• pp.581-588
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• 2011

Globalization of production, changing technology in ocean shipping sector, shifting bargaining power from port service provider to port users, changing distribution patterns of the containerization and new implementation for the environment and safety concerns introduced new ways of administration in port sector. In these days, port industries cannot survive alone. Port operation and management has to be proactive to cooperate and integrate with other port operators or other industries. In the 21st century, cooperation in maritime sector is more common than that in the past with several different reasons in a mixture of forms of cooperation. Cooperation among port authorities, port operators, shipping line, inland transport service providers and/or related organizations themselves becomes to exist to overcome the challenges and development of the global transport chain. This paper investigates the concept of port cooperation and the case analysis of the cooperation in the port industry.

• Journal of information and communication convergence engineering
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• v.18 no.4
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• pp.254-259
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• 2020

Phased-array antennas comprise a demanding antenna design methodology for commercial wireless communication systems or military radar systems. In addition to these two important applications, the phased-array antennas can be used in beamforming for wireless charging. In this study, a four-way analog beamforming front-end module (FEM) for a hybrid beamforming system is developed for 2.4 GHz operation. In a hybrid beamforming scheme, an analog beamforming FEM in which the phase and amplitude of RF signal can be adjusted between the RF chain and phased-array antenna is required. With the beamforming and beam steering capability of the phased-array antennas, wireless RF power can be transmitted with high directivity to a designated receiver for wireless charging. The four-way analog beamforming FEM has a 32 dB gain dynamic range and a phase shifting range greater than 360°. The maximum output RF power of the four-way analog beamforming FEM is 40 dBm (=10 W) when combined the four individual RF paths are combined.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.1
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• pp.181-186
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• 2022

The world's electric automobile sector has shifted beyond technological environmental changes to a stage that has an impact on the market environment. And automakers are shifting from the existing strategy of "technological advantage → brand enhancement → sales expansion of existing internal combustion engine vehicles" to the expansion of the electric automobile market itself, which is to enhance market competitiveness. In addition, competition in the electric automotive parts market is expected to intensify due to the expansion of the business areas of existing parts makers and the entry of new companies, and development cooperation is expected to actively proceed to improve the efficiency of major eco-friendly parts. Along with this prospect, electric vehicles are expected to change the overall structure of the automobile industry, the overall growth of the electric vehicle value chain such as batteries, power trains (motors, power management and control systems), electric vehicle production, and charging infrastructure Is expected. Therefore, in this thesis, in order to cultivate a variety of high-quality human resources that companies want to keep pace with the changing automobile industry, we study a professional manpower training program that leads the growth engine of the electric automobile industry.