• Korean Journal of Materials Research
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• v.28 no.1
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• pp.38-42
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• 2018

Continuous efforts are being made to improve the efficiency of Si solar cells, which is the prevailing technology at this time. As opposed to the standard front-lit solar cell design, the back-lit design suffers no shading loss because all the metal electrodes are placed on one side close to the pn junction, which is referred to as the front side, and the incoming light enters the denuded back side. In this study, a systematic comparison between the two designs was conducted by means of computer simulation. Medici, a two-dimensional semiconductor device simulation tool, was utilized for this purpose. The $0.6{\mu}m$ wavelength, the peak value for the AM-1.5 illumination, was chosen for the incident photons, and the minority-carrier recombination lifetime (${\tau}$), a key indicator of the Si substrate quality, was the main variable in the simulation on a p-type $150{\mu}m$ thick Si substrate. Qualitatively, minority-carrier recombination affected the short circuit current (Isc) but not the opencircuit voltage (Voc). The latter was most affected by series resistance associated with the electrode locations. Quantitatively, when ${\tau}{\leq}500{\mu}s$, the simulation yielded the solar cell power outputs of $20.7mW{\cdot}cm^{-2}$ and $18.6mW{\cdot}cm^{-2}$, respectively, for the front-lit and back-lit cells, a reasonable 10 % difference. However, when ${\tau}$ < $500{\mu}s$, the difference was 20 % or more, making the back-lit design less than competitive. We concluded that the back-lit design, despite its inherent benefits, is not suitable for a broad range of Si solar cells but may only be applicable in the high-end cells where float-zone (FZ) or magnetic Czochralski (MCZ) Si crystals of the highest quality are used as the substrate.

• Current Photovoltaic Research
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• v.2 no.2
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• pp.59-62
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• 2014

Minority carrier diffusion length is one of the most important parameters of solar cells, especially for short circuit current density (Jsc). In this report, we proposed the calculating method of the minority carrier diffusion length ($L_n$) in CIGS solar cells through biased quantum efficiency (QE). To verify this method's reliability, we chose two CIGS samples which have different grain size and calculated $L_n$ for each sample. First of all, we calculated out that $L_n$ was 56nm and 97nm for small and large grain sized-cell through this method, respectively. Second, we found out the large grain sized-cell has about 7 times lower defect density than the small grain sized-cell using drive level capacitance profiling (DLCP) method. Consequently, we confirmed that $L_n$ was mainly affected by the micro-structure and defect density of CIGS layer, and could explain the cause of Jsc difference between two samples having same band gap.

• Journal of the Korea Fashion and Costume Design Association
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• v.7 no.3
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• pp.167-179
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• 2005

Skirts hold an important position in dress culture among various dress forms, being worn by more than half of mu. In this study, Chima is defined as garment for lower part of the body without crotch sewing, contrasting with trousers. The authors classify and compare the formation of the skirts of minority races in Yunnan area, based on Korean Chima, understanding the forms of skirts and examining the composition, color, pattern and material. For the study, the authors investigated 57 pieces of skirts among 341 pieces of minority races dresses from Yunn Nationality Museum collection exhibited at Korea Folk Village in May 2003, and referred to customs materials and photos in various literatures. Skirts in Yunnan area are divided into 6 areas, that is, seamless one-piece skirt area, wrapskirt area and mixed type skirt area. Skirt formation factors from the effect of environment such as climate, lifestyle and means of production were studied, and characteristics, differences and similarities were reviewed. Figure of skirts are studied by compostion, color, material, and technique. By composition, they can be classified based on the similarity to Hanbok (traditional Korean dress). By color, worshipped color and preferred color vary by races and by area. Materials vary in kinds and thickness by area with various climate. By technique, national characteristic patterns are inherited through national traditional dyeing and embroidery. It is not easy to conclude based on single item of skirt, but we suggest that national dresses have been settled through the mutual supplements between the effect of social and cultural exchange such as historical inheritance, geological environment, religion and production activity and the various forms of skirts from changes in shape, color, material and wearing form of dresses.

• Journal of Internet Computing and Services
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• v.18 no.6
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• pp.113-125
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• 2017

This study focused on the difference between the volume of rumors and types of rumors via social media based on case studies and network analysis. Rumors are classified into core statement, peripheral statement, core gossip, and peripheral gossip based on their factuality and influence. The diffusion of opinions via social media is classified into dispersive mob, solid mob, dispersive minority, and solid minority based on the volume of node and its interactivity. The results of this study show that, core gossip is actively dispersed. Users are more interested in the influence of rumor than in rumors that appear the be factual. This study highlighted what the role of government when rumor is diffusing and in the aspect of message what the characteristic of rumor.

• Journal of dental hygiene science
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• v.18 no.3
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• pp.155-163
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• 2018

This study's aim was to investigate their opinions to improve the educational system for dental hygienists on the basis of their duties as dental hygienists. The qualitative study was conducted among 19 dental hygienists at Daejeon, Korea from July to August 2016. Two researchers followed each subject for working hours in a day and recorded all the tasks and time to take for each task. After one day, the researchers met each subject and conducted face-to-face interviews to investigate the opinions about the dental hygiene curriculum and national board examination. The main duties recognized by more than half of the subjects were oral disease prevention including scaling and dental treatment assistance. The subjects' minority opinion about the main duties included radiography, impression taking, dental implant surgery assistance, orthodontic treatment, patient counseling, dental management and staff management, and oral health education. The most important tasks perceived by the subjects were prosthetic and implant impressions, scaling and implant surgery assistance. The subjects' minority opinion about the most important duties included patient counseling and making temporary crowns. The most difficult tasks answered by the subjects were prosthetic and implant impressions and dental implant surgery assistance. The subjects' minority opinion about it included patient counseling, scaling, and making temporary crowns. They mentioned that their curriculum in college was different from the actual work and the national board examination was not reflective of their real duties. We found out Korean dental hygienists had a lot of roles as dental assistants, dental business managers, and so on. We suggest that the law, curriculum and national board examination for dental hygienists should be revised to be able to reflect the reality of the clinical field.

• Transactions on Electrical and Electronic Materials
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• v.4 no.6
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• pp.17-20
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• 2003

This paper describes the effect of halogenic gettering during oxide passivation of commercial solar cell with the $N^{+}$-P-$N^{+}$ structure. In order to study the effect of halogenic gettering on $N^{+}$-P-$N^{+}$ structure mono-crystalline silicon solar cell, we performed conventional POCl$_3$ diffusion for emitter formation and oxide passivation in the presence of HCl vapors. The $N^{+}$-P-$N^{+}$ structure based silicon solar cells were found to have higher short circuit current and minority carrier lifetime. Their performance was also found to be superior than the conventional $N^{+}$-P-$N^{+}$ structure based mono-crystalline silicon solar cell. The cell parameters of the $n^{+}$-p-$p^{+}$ and $n^{+}$-p-$n^{+}$ structure based cells, passivated by HCl assisted oxidation were measured. The improvement in $I_{sc}$ was attributed to the effect of the increased diffusion length of minority carriers, which came from the halogenic gettering effect during the growth of passivating oxide. The presence of chlorine caused gettering of the cells by removing the heavy metals, if any. The other advantage of the presence of chlorine was the removal of the diffusion induced (in oxygen environment) stacking faults and line defects from the surfaces of the silicon wafers. All these effects caused the improvement of the minority carrier lifetime, which in-turn helped to improve the quality of the solar cells.

• The Journal of the Korea Contents Association
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• v.9 no.6
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• pp.444-455
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• 2009

The selective central curriculum, which has been applied to the grades eleven and twelve in the 7th curriculum, has not operated well due to lack of teacher supply. This study analyzes the needs for the contents which are necessary to operate the minority optional curriculum through cyber education. Based on the developed contents, pilot program was performed. As a result of the program, the learning progress ratio of students was high but their satisfaction was very low. It is suggested that the quantity of the content should be reduced and the degree of difficulty lowered in order to address the problems. Another suggestion is to provide students with on-line teachers such as learning planners, tutors, and consultations to systematically manage students' learning. In addition, various elective-courses should be developed to allow students to take the courses of their choice, which in turn requires the establishment of the national operation system for the minority optional curriculum.

• Journal of Digital Convergence
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• v.17 no.9
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• pp.71-78
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• 2019

This study aims to identify good borrowers within the context of P2P lending. P2P lending is a growing platform that allows individuals to lend and borrow money from each other. Inherent in any loans is credit risk of borrowers and needs to be considered before any lending. Specifically in the context of P2P lending, traditional models fall short and thus this study aimed to rectify this as well as explore the problem of class imbalances seen within credit risk data sets. This study implemented an over-sampling technique known as Synthetic Minority Over-sampling Technique (SMOTE). To test our approach, we implemented five benchmarking classifiers such as support vector machines, logistic regression, k-nearest neighbor, random forest, and deep neural network. The data sample used was retrieved from the publicly available LendingClub dataset. The proposed SMOTE revealed significantly improved results in comparison with the benchmarking classifiers. These results should help actors engaged within P2P lending to make better informed decisions when selecting potential borrowers eliminating the higher risks present in P2P lending.

• The Korean Journal of Archival Studies
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• no.49
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• pp.121-173
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• 2016

An election is a major event in a country that elects the people's representatives. Currently, Korea's electoral system has a structure that limits the exclusion of the minority's opinion. Also, it has strengthened the monopoly of major political parties. Despite the harsh conditions, Green Party Korea has proposed an alternative to prevent even the minority from being excluded by practicing direct democracy and expanding proportional representation through the institutionalization of the democratic process within the party. Election campaigns should thus reflect this orientation of Green Party Korea. The local elections and the national elections reflect Korea's political and social status and show the course over two minority parties beyond such limits. Moreover, they provide evidence of the activities of Green Party Korea. The paper analyzes how the election archives of the party hold the values of democracy, how minor parties jump to another because of the unfavorable election system, and how the archives of Green Party Korea reflect its values on the political history of Korea.

• The Research Journal of the Costume Culture
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• v.29 no.4
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• pp.585-602
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• 2021

The purpose of this study is twofold: First, to develop new sustainable design methods (aligned with ethnic elements and traditional culture) combined with three-dimensional digital clothing technology throughout the design process, which can be presented as guideline materials for various fashion designs to be developed in contemporary sensibilities. Second, it is the intention to produce creative fashion designs by incorporating the characteristics and methods of Miao's Huangping batik dyeing technique and to present various possibilities in the fashion design field. The overall design characteristics sought by Miao minority are in line with the complex terrain and the ecological and climatic conditions. Miaoist batik dyeing (registered as part of Chinese national intangible cultural heritage) features unique production methods and patterns. The study results are as follows. First, this attempt has enabled understanding of the national costume culture as Chinese Miao's traditional cultural heritage to be promoted, while the direction of contemporary design development using traditional elements has been presented. Second, the study demonstrated new and innovative expressions and styles relying on three-dimensional digital contouring technology and identified the possibility of developing various designs. Third, it was confirmed that the dyed batik pattern design created by the three-dimensional digital contouring technology could be recombined or expanded as digital printing to express the traditional ethnic designs in a practical manner utilizing digital printing techniques based on traditional characteristics.