• Title/Summary/Keyword: minority minority

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Estimation of mechanical damage by minority carrier recombination lifetime and near surface micro defect in silicon wafer (실리콘 웨이퍼에서 소수 반송자 재결합 수명과 표면 부위 미세 결함에 의한 기계적 손상 평가)

  • 최치영;조상희
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.2
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    • pp.157-161
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    • 1999
  • We investigated the effect of mechanical back side damage in Czochralski silicon wafer. The intensity of mechanical damage was evaluated by minority carrier recombination lifetime by laser excitation/microwave reflection photoconductance decay ($\mu$-PCD) technique, wet oxidation/preferential etching methods, near surface micro defect (NSMD) analysis, and X-ray section topography. The data indicate that the higher the mechanical damage intensity, the lower the minority carrier lifetime, and NSMD density increased proportionally, also correlated to the oxidation induced stacking fault (OISF) density. Thus, NSMD technique can be used separately from conventional etching method in OISF measurement.

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Development of fashion design applied to costume of the Chinese Minority Xinjiang Uygur (중국 신장 위구르족 복식의 특성을 활용한 패션 디자인)

  • Wang, Lifeng;Lee, Younhee
    • The Research Journal of the Costume Culture
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    • v.28 no.4
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    • pp.492-507
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    • 2020
  • This study aims to develop fashion designs that combine atlas fabric with the characteristics of Uygur costume to modernize the costume of the Xinjiang Uygur. Research contents and methods are as follows. First, based on previous studies, research analysis was conducted on the cultural background, clothing characteristics, and material of Uygur clothing. Second, based on such research contents, designs combining the characteristics of Uygur costume and atlas fabric were presented. Third, to analyze the utilization of atlas fabric and examine fabric characteristics, material was gathered from collections on domestic and foreign web sites. Through field explorations of local museums in the Xinjiang area, minority group culture was observed in more detail. Based on collection of traditional clothing and analysis of its characteristics, fashion designs that apply contemporary trends were developed. General silhouettes without any restrictions to the waist and decorations made using embroidery were often used. Atlas silk, developed in China using Ikat weaving methods, is an important traditional clothing fabric of the minority group Xinjiang. Based on such data collection analysis, the produced works highlighted traditional ethnic characteristics by extracting classical patterns of atlas fabric, modifying or partially expanding them, combining them with hand knitting, and adding contemporary sensations, thus providing confirmations of the possibility of popularizing classic patterns in more practical manners.

Plasma nitridation of atomic layer deposition-Al2O3 by NH3 in PECVD

  • Cha, Ham cho rom;Cho, Young Joon;Chang, Hyo Sik
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.304.1-304.1
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    • 2016
  • We have investigated the effect of plasma nitridation of atomic layer deposited-Al2O3 films of monocrystalline Si wafers and the thermal properties of nitridated Al2O3 films. Nitridation was performed on Al2O3 to form aluminum oxynitride (AlON) using NH3 plasma treatment in a plasma-enhanced chemical vapor deposition and it was conducted at temperature of $400^{\circ}C$ with various plasma power condition. After nitridation, we performed firing and forming gas annealing (FGA). For each step, we have observed the minority carrier lifetime and the implied Voc by using quasi-Steady-State photoconductance (QSSPC). We confirmed a tendency to increase the minority carrier lifetime and the implied Voc after the nitridation. On the other hand, the minority carrier lifetime and the implied Voc was decreased after Firing and forming gas annealing (FGA). To get more information, we studied properties of the plasma treated Al2O3 films by using Secondary Ion Mass Spectroscopy (SIMS) and X-ray Photoelectron Spectroscopy (XPS).

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Evaluation of mechanical backside damage by minority carrier recombination lifetime and photo-acoustic displacement method in silicon wafer (실리콘 웨이퍼에서 광열 변위법과 소수 반송자 재결합 수명 측정에 의한 기계적 후면 손상 평가)

  • 최치영;조상희
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.8 no.1
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    • pp.117-123
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    • 1998
  • We investigated the effect of mechanical backside damage in Czochralski grown silicon wafer. The intensity of mechanical damage was evaluated by minority carrier recombination lifetime by laser excitation/microwave reflection photoconductivity decay method, photo-acoustic displacement method, X-ray section topography, and wet oxidation/preferential etching methods. The data indicate that the higher the mechanical damage intensity, the lower the minority carrier lifetime, and the photo-acoustic displacement values increased proportionally, and it was at Grade 1: Grade 2:Grade 3 = 1:19.6:41 that the normalized relative quantization ratio of excess photo-acoustic displacement in damaged wafer was calculated, which are normalized to the excess PAD from sample Grade 1.

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Utilization of the surface damage as gettering sink in the silicon wafers useful for the solar cell fabrication (태양전지용 규소 기판에 존재하는 기계적 손상의 gettering 공정에의 활용)

  • Kim, Dae-Il;Kim, Young-Kwan
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.16 no.2
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    • pp.66-70
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    • 2006
  • Various kind of structural defects are observed to be present on the oxidized surface of the silicon crystal which was previously damaged mechanically. The formation of such defects was found to depend on the amount of damage induced and the temperature of thermal oxidation. It was confirmed by the measurement of minority carrier life time that gettering capability decreases as the size of the defects increase. The strained layer which is formed due to smaller amount of damage or lower oxidation temperature believed to has higher capability of gettering over defects like dislocation loops or stacking faults.

유전자 알고리즘을 활용한 데이터 불균형 해소 기법의 조합적 활용

  • Jang, Yeong-Sik;Kim, Jong-U;Heo, Jun
    • Proceedings of the Korea Inteligent Information System Society Conference
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    • 2007.05a
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    • pp.309-320
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    • 2007
  • The data imbalance problem which can be uncounted in data mining classification problems typically means that there are more or less instances in a class than those in other classes. It causes low prediction accuracy of the minority class because classifiers tend to assign instances to major classes and ignore the minor class to reduce overall misclassification rate. In order to solve the data imbalance problem, there has been proposed a number of techniques based on resampling with replacement, adjusting decision thresholds, and adjusting the cost of the different classes. In this paper, we study the feasibility of the combination usage of the techniques previously proposed to deal with the data imbalance problem, and suggest a combination method using genetic algorithm to find the optimal combination ratio of the techniques. To improve the prediction accuracy of a minority class, we determine the combination ratio based on the F-value of the minority class as the fitness function of genetic algorithm. To compare the performance with those of single techniques and the matrix-style combination of random percentage, we performed experiments using four public datasets which has been generally used to compare the performance of methods for the data imbalance problem. From the results of experiments, we can find the usefulness of the proposed method.

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Interface Passivation Properties of Crystalline Silicon Wafer Using Hydrogenated Amorphous Silicon Thin Film by Hot-Wire CVD (열선 CVD법으로 증착된 비정질 실리콘 박막과 결정질 실리콘 기판 계면의 passivation 특성 분석)

  • Kim, Chan-Seok;Jeong, Dae-Young;Song, Jun-Yong;Park, Sang-Hyun;Cho, Jun-Sik;Yoon, Kyoung-Hoon;Song, Jin-Soo;Kim, Dong-Hwan;Yi, Jun-Sin;Lee, Jeong-Chul
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.172-175
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    • 2009
  • n-type crystalline silicon wafers were passivated with intrinsic a-Si:H thin films on both sides using HWCVD. Minority carrier lifetime measurement was used to verify interface passivation properties between a-Si:H thin film and crystalline Si wafer. Thin film interface characteristics were investigated depending on $H_2/SiH_4$ ratio and hot wire deposition temperature. Vacuum annealing were processed after deposition a-Si:H thin films on both sides to investigate thermal effects from post process steps. We noticed the effect of interface passivation properties according to $H_2/SiH_4$ ratio and hot wire deposition temperature, and we had maximum point of minority carrier lifetime at H2/SiH4 10 ratio and $1600^{\circ}C$ wire temperature.

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A Fair and Efficient Congestion Avoidance Scheme Based on the Minority Game

  • Kutsuna, Hiroshi;Fujita, Satoshi
    • Journal of Information Processing Systems
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    • v.7 no.3
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    • pp.531-542
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    • 2011
  • In this paper, we propose a new congestion control scheme for high-speed networks. The basic idea of our proposed scheme is to adopt a game theory called, "Minority Game" (MG), to realize a selective reduction of the transmission speed of senders. More concretely, upon detecting any congestion, the scheme starts a game among all senders who are participating in the communication. The losers of the game reduce the transmission speed by a multiplicative factor. MG is a game that has recently attracted considerable attention, and it is known to have a remarkable property so that the number of winners converges to a half the number of players in spite of the selfish behavior of the players to increase its own profit. By using this property of MG, we can realize a fair reduction of the transmission speed, which is more efficient than the previous schemes in which all senders uniformly reduce their transmission speed. The effect of the proposed scheme is evaluated by simulation. The result of simulations indicates that the proposed scheme certainly realizes a selective reduction of the transmission speed. It is sufficiently fair compared to other simple randomized schemes and is sufficiently efficient compared to other conventional schemes.

A Comparative Study on Pigtails for the Mongolian and the Koryo Dynasty (몽골과 고려의 변발 연구)

  • Kim Ki-Sun
    • Journal of the Korea Fashion and Costume Design Association
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    • v.7 no.1
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    • pp.113-124
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    • 2005
  • Information sources about Mongolian pigtail of 13-14C are relatively rich. But it was difficult to estimate the shape of the pigtail in detail with the descriptions in historical writing or travel books only, and paintings were neither enough to observe the beautiful shape of the pigtail closely on the whole because the portrayed characters were always wearing their hats. However, the authors could trace the detailed shape of the pigtail of 13-14C through close investigation into Mongolian stone statue of the period. In conclusion, the authors performed a comparative study by historically comparing the historical writings, archeological materials, ethnological materials and figurative arts featuring medieval Mongolian pigtail. And the authors paid careful attention to the meaning of those materials to the hairdo history. Historically nothern minority races have become assimilated with surrounding races in language, culture and customs through long economical and cultural exchange, and today their national traits gradually fade away by globalization. But each minority race still stands independently and maintain its own traditional culture. only recently began the study by Korean researchers on Mongolian pigtail, and there is still much to be discussed in ethnological issues such as racial pedigree.

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Performance Improvement of DCF through Transmission Control (전송제어를 통한 DCF의 성능 향상)

  • Park, Jaesung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.12
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    • pp.1811-1813
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    • 2016
  • DCF (Distributed Coordination Function) resolves the channel contention problem in a distributed manner by forcing nodes to randomly choose a waiting time in a contention window. However, since the size of a contention is limited, the collision probability increases with the number of sending nodes. To resolve the problem, in this paper, we propose a transmission control method based on the minority game (MG). Each node can determine autonomously whether to send or not without message exchanges with other nodes to maximize its profit. Through simulation studies, we verify that the proposed method can improves the performance of DCF in terms of collision probability in a congestion situation.