• Proceedings of the Korean Society of Computer Information Conference
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• 2015.07a
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• pp.87-88
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• 2015

최근 IT기술의 발전과 더불어 보안의 중요성이 부각되면서 Pin Number, Password, Pattern Recognition 등 인증 방식에 대한 연구가 진행되고 있지만 위와 같은 One-factor 인증 시스템에는 "Shoulder Attack"과 같은 사용자 레벨에서의 보안공격에 취약하다. 위와 같은 문제점을 해결하기 위하여 'Google E-mail' 등 일부 강화된 보안이 필요한 시스템에서는 추가 모듈을 이용한 Two-factor 인증 시스템을 적용하여 보안을 제공하고 있지만 사용상의 번거로움과 복잡성으로 인해 고도의 보안 기술의 적용을 받지 못하는 등 많은 제약사항이 남아있다. 본 논문에서는 위 와 같은 One-factor 시스템의 취약점을 파악하여 그에 따라 보안 인증 절차를 향상시키기 위해 암호화와 인증 방법으로 지문인식을 사용하여 Multi-level 인증 시스템을 제안한다. 본 시스템은 Send 디비이스를 구현한 아두이노를 통해 M2M 서비스를 수행하며, 암호와 지문 정보를 아두이노 디바이스에 저장하여 두 가지의 신뢰적인 정보를 바탕으로 인증하는 시스템이다. 아두이노를 이용하여 디바이스 분리를 통한 사용자 레벨에서의 보안을 강하고 지문인식을 통해 불편함과 복잡성을 간소화하였다.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.88-89
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• 2017

This paper investigates the design of multi-winding coupled inductor for minimum inductor current ripple in rapid traction battery charger systems. Based on the general circuit model of multi-winding coupled inductor together with the operating principles of dc-dc converter, the relationship between the ripple size of inductor current and the coupling factor is derived under the different duty ratio. The optimal coupling factor which corresponds to a minimum inductor ripple current becomes -(1/n-1), i.e. a complete inverse coupling without leakage inductance, as the steady-state duty ratio operating point approaches 1/n, 2/n, … or (n1)/n. In an opposite manner, the optimal coupling factor value of zero, i.e. zero mutual inductance, is required when the steady-state duty ratio operating point approaches either zero or one.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.3
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• pp.471-478
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• 2002

In real structures, multi-spot welded joints are more frequently used than a single-spot welded joint. Most researches, however, have been focused to a single-spot welded joint until now. In this paper, the fatigue behavior of multi-spot welded joints are investigated using the finite element solutions of the multi-spot welded specimens. The local strain approach is used rather than the stress intensity factor approach to estimate the fatigue life since the former is quite simple and straightforward. It is found that the fatigue behavior of multi-spot welded joints is different from that of single-spot welded joints. The local strain approach is still applicable to multi-spot welded joints.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.2
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• pp.16-23
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• 2006

Recently the design of multi-stage gear drive is being highly concerned. Until now, since the researches of gear drive are focused on the design for satisfying safety factor, the reliability evaluation of multi-stage gear drive is not included. In this paper, the life and reliability models of multi-stage gear drive are proposed using methods of probability and statistics. The life and reliability of the multi-stage gear drive have been evaluated, which is based on the life and reliability of each stage gear drive. The pinion and gear lives of each stage are calculated using the Lundberg-Palmgren theory and the Weibull failure distribution. These lives are combined using methods of probability and statistics to produce a life and reliability model of multi-stage gear drive.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2669-2671
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• 2001

In this paper, we propose design a Multi-Fuzzy Inference model structure. In order to determine structure of the proposed Multi-Fuzzy Inference model, HCM clustering method is used. The parameters of membership function of the Multi-Fuzzy are identified by genetic algorithms. A aggregate performance index with a weighting factor is used to achieve a sound balance between approximation and generalization abilities of the model. We use simplified inference and linear inference as inference method of the proposed Multi-Fuzzy model and the standard least square method for estimating consequence parameters of the Multi-Fuzzy. Finally, we use some of numerical data to evaluate the proposed Multi-Fuzzy model and discuss about the usefulness.

• Management & Information Systems Review
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• v.25
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• pp.371-386
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• 2008

In this study, the hypothesized model of internet user satisfaction in e-commerce environment is developed and the relationships among constructs in the model are examined. A Confirmatory factor analysis is employed to analyze the relationships between the multiple dependent variables and independent variables.

• Progress in Medical Physics
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• v.19 no.4
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• pp.256-262
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• 2008

To evaluate the metabolic changes in normal adult brains due to alterations SENSE and NEX (number of excitation) by multi voxel MR Spectroscopy at 3.0 Tesla. The study group was composed of normal volunteers (5 men and 8 women) with a mean ($\pm$ standard deviation) age of 41 (${\pm}11.65$). Their ages ranged from 28 to 61 years. MR Spectroscopy was performed with a 3.0T Achieva Release Version 2.0 (Philips Medical System-Netherlands). The 8 channel head coil was employed for MRS acquisition. The 13 volunteers underwent multi voxel spectroscopy (MVS) and single voxel spectroscopy (SVS) on the thalamus area with normally gray matter. Spectral parameters were as follows: 15 mm of thickness; 230 mm of FOV (field of view); 2000 msecs of repetition time (TR); 288 msecs of echo time (TE); $110{\times}110$ mm of VOI (view of interest); $15{\times}15{\times}15$ mm of voxel size. Multi voxel spectral parameters were made using specially in alteration of SENSE factor (1~3) and 1~2 of NEX. All MRS data were processed by the jMRUI 3.0 Version. There was no significant difference in NAA/Cr and Cho/Cr ratio between MVS and SVS likewise the previous results by Ross and coworkers in 1994. In addition, despite the alterations of SENSE factor and NEX in MVS, the metabolite ratios were not changed (F-value : 1.37, D.F : 3, P-value : 0.262). However, line-width of NAA peak in MVS was 3 times bigger than that in SVS. In the present study, we demonstrated that the alterations of SENSE factor and NEX were not critically affective to the result of metabolic ratios in the normal brain tissue.

• Current Photovoltaic Research
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• v.7 no.3
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• pp.65-70
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• 2019

As a demand of higher power photovoltaic modules, shingled, multi-busbar, half-cell, and bifacial techniques are developed. Multi-busbar module has advantage for large amount of light havesting. And, half-cell is high power module for reducing resistive losses and higher shade tolerance. Recently, researches on multi-busbar is focused on reliability according to adhesion and intermetallic compound between Sn-Pb solder and Ag electrode. And half-cell module is researched to comparing with full-sized cell module for structure difference. In this study, we investigated the factors affecting to efficiency and adhesion of multi-wires half-cell module according to wire thickness, solder thickness, and flux. The results of solar simulator and peel test was that peel strength and efficiency of soldered cell is not related. But samples with flux including high solid material showed high efficiency. The results of FE-SEM and EDX line scan on cross-section between wire and Ag electrode for different flux showed thickness of solder joint between wire and Ag electrode is increasing through solid material increasing. Flux including high solid material would affect to solder behavior on Ag electrode. Higher solid material occurred lower growth of IMC layer because solder permeate to sider of wire ribbon than Ag electrode. And it increased fill factor for high efficiency. In soldering process, amount of solid material in flux and solder thickness are the factor related with characteristic of soldered photovoltaic cell.

• Journal of Fashion Business
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• v.25 no.2
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• pp.18-33
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• 2021

This study sought to understand the clothing consumption values of male consumers and analyze the attributes of online fashion multi-brand stores. The study examined the effect of clothing consumption values of male consumers on the perceived attributes of online fashion multi-brand stores and use intention. The study also aimed to investigate whether online information search moderated the relationship between the perceived attributes of online fashion multi-brand stores and use intention. An online survey of male consumers in their 20s and 30s was conducted, and a total of 338 responses were analyzed. The SPSS 24.0 program was used to perform frequency analysis, factor analysis, reliability analysis, regression analysis, and stepwise-regression analysis. The results are as follows. First, fashionableness out of the four attributes of online fashion multi-brand stores (fashionableness, entertainment, variety, and scarcity) influenced the practical and conspicuous values of clothing consumption values. Entertainment had a significant effect on all clothing consumption values. Variety had a significant impact on practical and conspicuous values and the scarcity factor influenced epistemic and conspicuous values. Second, while entertainment, variety, and scarcity influenced sharing intention, fashion, entertainment, and variety influenced purchase intention. Third, online information search moderated the relationship between the perceived attributes of online fashion multi-brand stores and sharing intention but not purchase intention.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.18 no.3
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• pp.55-69
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• 2010

The role of airports in the metropolitan area in Korea is very important which is located on the center of Northeast Asia considered as the highest potential growth continent in the world air transport market. This study includes comparison on service quality between Gimpo Airport and Incheon Airport which are indicated as multi-airport system in the metropolitan area appraised by passengers from Korea, Japan and China, and analysis on primary factors of airport service which affect the customer satisfaction and loyalty. The service quality appraised in the order of Chinese, Korean, and Japanese and the analysis result indicated that the service quality factors which influence on customer satisfaction and loyalty were all different among passengers from three countries. Information service was the priority factor for customer satisfaction to Chinese and Korean, but Japanese considered that personal service was the most important factor. This research paper tried to provide many current issues and guides to operational strategy including plan for the specialized routes of multi-airport system in domestic metropolitan area.