• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.374-379
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• 2001

The satellite electronic equipment is exposed to high level random vibration environment during the launch of spacecraft. The random vibration can cause damage of electronic equipment. Thus very careful consideration on the launch environment, especially for high level random vibration, is required in the design stage of transponder equipments of communication satellite. For the structural integrity of the communication satellite transponder equipment under qualification level random vibration, Finite Element analysis was carried out using the commercial code, MSC/Nastran and ANSYS and stress levels are presented. In order to validate the femodel, modal test was also performed and compared with numerical results.

• Journal of Electrical Engineering and Technology
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• v.5 no.4
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• pp.561-570
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• 2010

This paper presents an advanced dynamic simulation model of a proton exchange membrane fuel cell for the optimal design of a fuel cell power conditioning system (FC-PCS). For the development of fuel cell models, the dynamic characteristics of the fuel cell are considered, including its static characteristics. Then, software fuel cell simulation is realized using Matlab-Simulink. Specifically, the design consideration of PCS (i.e., power semiconductor switch, capacitor, and inductor) is discussed by comparatively analyzing the developed simulator and ideal DC source. In addition, a cosimulation between the fuel cell model and PCS realized using the PSIM software is performed with the help of the SimCoupler module. Detailed analysis and informative simulation results are provided for the optimal design of fuel cell PCS.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.7
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• pp.3080-3099
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• 2016

In this paper, we propose an algorithm for energy efficient cooperative communication in wireless sensor network (WSN). The algorithm computes the appropriate transmission distance corresponding to optimal broadcast bit error probability, while taking the circuit energy consumption and the number of cooperating nodes into consideration. The algorithm guarantees minimum energy consumption by choosing higher value of bit error probability for cooperative phase and lower value of bit error probability for broadcast phase while maintaining the required end-to-end reliability. The simulation results show that the proposed algorithm provides significant energy saving gain when compared with traditional fixed distance schemes and is suitable for applications demanding energy efficiency with high quality of reception.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.5
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• pp.1733-1751
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• 2015

The IEEE 802.15.4 standard not only provides a maximum of seven guaranteed time slots (GTSs) for allocation within a superframe to support time-critical traffic, but also achieves ultralow complexity, cost, and power in low-rate and short-distance wireless personal area networks (WPANs). Real-time wireless body area sensor networks (WBASNs), as a special purpose WPAN, can perfectly use the IEEE 802. 15. 4 standard for its wireless connection. In this paper, we propose an adaptive GTS allocation scheme for real-time WBASN data transmissions with different priorities in consideration of low latency, fairness, and bandwidth utilization. The proposed GTS allocation scheme combines a weight-based priority assignment algorithm with an innovative starvation avoidance scheme. Simulation results show that the proposed method significantly outperforms the existing GTS implementation for the traditional IEEE 802.15.4 in terms of average delay, contention free period bandwidth utilization, and fairness.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.5
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• pp.2218-2244
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• 2016

In this paper, we propose a hybrid routing scheme that utilizes location information to support reliable data transmission in mobile ad hoc networks. The proposed scheme determines and maintains routing path by considering the directionality and connectivity of nodes using grid zones and information on neighbor nodes. In addition, it generates alternative paths with consideration for node distance and reliability. To show the superiority of the proposed routing scheme, a performance evaluation was conducted using simulations. The performance evaluation results show that the proposed scheme offers faster and more reliable data transmission than the existing routing schemes, and the number of messages decreases by approximately 31% compared to the existing schemes on average.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.7
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• pp.1512-1515
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• 2004

Information transfer technology using Internet is basic means today. Therefore, we have to consider the information through internet. The main key is Information security against attacker. We have proposed the method employing security mechanism under ubiquitous environment. To realize the Information security for optical communication, we need requirement for a variety of consideration and propose the method..

• International Journal of Contents
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• v.12 no.2
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• pp.37-41
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• 2016

In this paper, we propose a friend recommendation scheme that takes into consideration the attribute information of a POI and a user's movement patterns. The proposed scheme broadly consists of a part that filters out other users who have different preferences by calculating preferences using the attribute information of users and a part that finds a moving trajectory close to that of a user with a pattern-matching scheme. To verify the superiority of the proposed scheme, we compare it with existing schemes through various performance evaluations.

• Educational Technology International
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• v.10 no.2
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• pp.107-125
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• 2009

This study seeks to prove three points through the research. The first point is to examine the changes of international attitudes with actual experiences using synchronous international distance learning. The second point is to examine the effectiveness of a synchronous international distance system. And the final point is to compare international attitudes among middle school and undergraduate school students in Korea and Japan. The study used the DVTS for audio and video communication tools and automatic translating chat as a text communication tool. This combination of communication tools was very effective for students from both countries to communicate for international collaborative learning activities. The study found several interesting patterns of attitude change from the results of the study. For whole category analysis, there are positive changes in four categories of international attitudes: consciousness to foreign countries, consideration for other's viewpoints, motivation for international education, and recognition for the counterpart country. However, there was no change in the nationality category.

• The Journal of the Korea Contents Association
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• v.18 no.8
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• pp.255-261
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• 2018

The purpose of this research is to discover the value of experiencing the humanistic spirit of sharing, consideration, sympathy, and communication through the mentoring program between different generations through the . The provides collective mentoring to menti to involuntarily participating mentees, prioritizing traits such as truthfulness, flexibility, and consideration for others. The sharing within the is the sharing of human traits, and displays the characteristics of volunteering. For better mutual connection and interdependence between the mentor and mentee, concentration, sympathy, understanding, and assurance is also needed. Also, sympathy is key trait that both mentors and mentees should possess, along with communication, the lacking of which causes the contradictions within our society and amplification of generational conflicts. Thus, the show the potential to become a unique mentoring program that uses culture and art to experience the humanistic spirit. Also, this program is valuable in that it provides the opportunity for the matured generation to contribute to the local community.

• Korean journal of food and cookery science
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• v.30 no.4
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• pp.412-418
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• 2014

This study considered the selection attributes of bakery consumers and schematized characteristic attributes of being selected by customers by image through a correspondence analysis in terms of own preferring bakery. Self-administrated questionnaires were completed by consumers (452 samples), and the data were analysed by frequency, chi-square, one-way ANOVA, reliability analysis and correspondence analysis. According to the survey results regarding the mean value on bakery selection attributes, it was shown to be in the order of taste ($4.73{\pm}0.70$), sanitation ($4.70{\pm}0.68$), service ($4.21{\pm}0.84$), price ($4.03{\pm}0.92$), consideration ($4.01{\pm}0.96$), communication ($4.01{\pm}0.96$), health ($3.99{\pm}0.98$), and location ($3.83{\pm}0.99$). In the analysis of difference with regard to the selection attributes according to the preferred bakery, both consideration ($4.05{\pm}0.90$) and communication ($3.98{\pm}0.93$) showed a high value in individual bakery, thereby presenting a significant difference (p<0.05). As a result of having carried out correspondence analysis in order to prepare an image map according to the preferred bakery, the selection attributes of employees' service and communication showed the closest image map to individual bakery. Location and sanitation were very close to franchise bakery. Further, other bakery shops were schematized in a relatively close distance to price.