• Proceedings of the KIPE Conference
• /
• 2014.07a
• /
• pp.116-117
• /
• 2014

본 논문에서는 3상 IPM을 사용하여 2상 유도전동기를 위한 2레그형 인버터를 설계하였다. 3상 IPM은 6개의 스위칭 소자를 내장하고 있어서 이중 4개는 2레그형 인버터로 사용하고, 나머지 2개는 역률제어 회로에 이용할 수 있다. 이렇게 하면 하드웨어의 추가를 최소화하면서 역률제어 기능을 갖는 2레그형 인버터를 구현할 수 있다. 2레그형 인버터에서는 반드시 직류링크에 2개의 커패시터를 직렬로 연결하는데, 입력 전원의 반주기 마다 각각의 커패시터에 충방전 동작이 수행된다. 이러한 동작으로 인해 2개의 커패시터에 전압 불균형이 발생할 수 있고 커패시터 용량이 서로 다를 경우에는 이 전압 리플이 더욱 커지게 되며, 이것은 전동기에 불평형 전류를 공급하게 되어 전동기의 토크리플을 발생시킨다. 본 논문에서는 직류링크의 전압 불균형 문제가 전동기에 미치는 영향을 분석하고, 이러한 전압 불균형을 보상하여 전동기의 토크리플을 제거하고 동작특성을 개선하는 방법을 제안하며, 컴퓨터 시뮬레이션을 통하여 이를 검증한다.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.13 no.2
• /
• pp.31-40
• /
• 2003

The current security issue for the Internet is focused on the security for user data. On the other hand, the research on the security for routing protocols is not so active, considering the importance of its role for the harmonious and accurate operation of the Internet. In this paper, we investigate the security problems of the link-state routing protocol which has been employed in the Internet, and suggest a new authentication mechanism for routing messages which complements and extends the previous ones. For this purpose, a concept of dual hash chains is newly introduced, which is provably secure, and we explain how to provide both the integrity and source authentication service for routing messages based on the session hash chains.

• Proceedings of the Korea Contents Association Conference
• /
• 2003.05a
• /
• pp.416-420
• /
• 2003

In this paper, we implemented a dual-resolution image database system for the fast naked-eye retrieval using interpolation. This system can solve two conventional problems : a blocking noise at zoom-out image in single high resolution method and a big storage to store in simple dual-resolution image database system. The proposed method makes a subsampled image by subsampling a original image, and then a interpolated image of it using interpolation. After that, a hybrid dual-resolution image database is composed based on the differential image between the interpolated image and the original image. Experimental results of simulating through 60 sample images shows that the proposed method is 0.011 second faster than simple high-resolution method in the retrieval time - one is 0.003 second, the other is 0.014 second, respectively. Also, that improves 14.7% more than simple dual-resolution method in the stored size - one is 19,821 byte, the other is 16,910 byte, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.11
• /
• pp.2621-2626
• /
• 2013

This paper has presented the potential distribution for asymmetric double gate(DG) MOSFET, and sloved Poisson equation to obtain the analytical solution of potential distribution. The symmetric DGMOSFET where both the front and the back gates are tied together is three terminal device and has the same current controllability for front and back gates. Meanwhile the asymmetric DGMOSFET is four terminal device and can separately determine current controllability for front and back gates. To approximate with experimental values, we have used the Gaussian function as doping distribution in Poisson equation. The potential distribution has been observed for gate bias voltage and gate oxide thickness and channel doping concentration of the asymmetric DGMOSFET. As a results, we know potential distribution is greatly changed for gate bias voltage and gate oxide thickness, especially for gate to increase gate oxide thickness. Also the potential distribution for source is changed greater than one of drain with increasing of channel doping concentration.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.35 no.4
• /
• pp.417-424
• /
• 2011

A fuel assembly consists of five major components, i.e., a top end piece (TEP), a bottom end piece (BEP), spacer grids (SGs), guide tubes (GTs) and an instrumentation tube (IT); in addition, it also includes fuel rods (FRs). The TEP/BEP should satisfy stress intensity limits according to the conditions A and B of ASME, Section III, Division 1-Subsection NB. In a dual-cooled fuel assembly, the array and position of fuel rods are different from those in a conventional PWR fuel assembly; these changes are necessary for achieving power uprating. The flow plates of the TEP and BEP have to be modified accordingly. The pattern and shape of the flow holes were newly designed. To verify the strength compatibility, the Tresca stress limit according to the ASME code was investigated in the case of an axial load of 22.241 kN. In this paper, the stress linearization procedure for strength evaluation of a newly designed TEP is presented.

• KIPS Transactions on Software and Data Engineering
• /
• v.9 no.2
• /
• pp.53-60
• /
• 2020

Sentiment analysis is the automated process of understanding attitudes and opinions about a given topic from written or spoken text. One of the sentiment analysis approaches is a dictionary-based approach, in which a sentiment dictionary plays an much important role. In this paper, we propose a method to automatically generate Korean sentiment lexicon from the well-known English sentiment lexicon called VADER (Valence Aware Dictionary and sEntiment Reasoner). The proposed method consists of three steps. The first step is to build a Korean-English bilingual lexicon using a Korean-English parallel corpus. The bilingual lexicon is a set of pairs between VADER sentiment words and Korean morphemes as candidates of Korean sentiment words. The second step is to construct a bilingual words graph using the bilingual lexicon. The third step is to run the label propagation algorithm throughout the bilingual graph. Finally a new Korean sentiment lexicon is generated by repeatedly applying the propagation algorithm until the values of all vertices converge. Empirically, the dictionary-based sentiment classifier using the Korean sentiment lexicon outperforms machine learning-based approaches on the KMU sentiment corpus and the Naver sentiment corpus. In the future, we will apply the proposed approach to generate multilingual sentiment lexica.

• Applied Microscopy
• /
• v.1 no.1
• /
• pp.35-42
• /
• 1969

가토간장에서 채취(採取)한 간(肝)디스토마 성충(成蟲)의 정소(精巢)와 수정낭(受精囊)을 1.25% glutaraldehyde와 1% 사산화(四酸化) 오스뮴산(酸)으로 냉실(冷室)에서 이중고정(二重固定)하였다. 고정(固定)된 시료(試料)는 양식(樣式)에 따라 탈수(脫水)한 후(後) Epon-812로 포매(包埋)하여 MT-2형(型) Porter Blum microtome으로서 초박절편(超薄切片)을 만들어 수사화연(水酸化鉛)과 초산(醋酸)우라닐로서 이중염색(二重染色)한후 Hitachi HS-7형(型)과 HU-11E형(型)의 전자현미경(電子顯微鏡)으로 관찰(觀察)하였다. 관찰결과 간(肝)디스토마의 정세포(精細胞)는 타원형으로 난형(卵形)의 인(仁)을 포함(包含)한 큰 핵(核)을 갖고 있으며 핵(核)을 둘러싼 비교적소량(比較的小量)의 세포질(細胞質)에는 낭형(囊形)의 조면소포체(粗面小胞體)가 희소(稀少)하게 있으며 유리(遊離)리보좀 및 즐(櫛)을 가진 미토콘드리아, 중심체(中心體), 층판상(層板狀)의 골지체가 있다. 정자(精子)는 긴 원주형(圓柱形)의 핵(核)과 선단(先端)에 첨체(尖體)를 포함(包含)한 두부(頭部)와 중종편(中終片), 미부(尾部)의 말단부(末端部)로 갈수록 점차 가늘어져서 결국(結局) 편모(鞭毛)로 끝난다. 두부(頭部)의 선단부(先端部) 가까이 핵환(核環)이 있으므로 이를 기시점(起始點)으로 직경(直徑) $250{\AA}$ 정도의 $8{\sim}10$개(個)의 미세소관(微細小管)이 축사(軸絲)의 배면(背面) 원형질막(原形質膜) 직내면(直內面)의 외형질(外形質)에 평행(平行)하게 중종편(中終片)까지 신장(伸長)되어 있다. 미토콘드리아는 융합(融合)되어 두부(頭部)의 후반부(後半部) 핵(核)의 복측(腹側)에 평행(平行)하게 축사(軸絲)를 감싸는 원추형(圓錐形)으로 종단면(縱斷面)에서 반점상(班點狀)의 횡문(橫紋)이 관찰(觀察)되었다. 중심체(中心體)에서 기원(起原)된 축사(軸絲)는 중심부(中心部)에 중심섬유(中心纖維)와 중심초 및 이중(二重)의 미세소관(微細小管)이 9개(個) 둘러싸고 있는 구조(構造)를 하고 있다.

• Clean Technology
• /
• v.14 no.4
• /
• pp.256-264
• /
• 2008

In this study, using PBAST (poly(butylene adipate-co-succinate-co-terephthalate)) which was eco-friendly biodegradable aliphatic polyester, PBAST/PVA (poly(vinyl alcohol)) double-layered hollow microspheres were prepared with the water/oil/water multiple emulsion ($W_1/O/W_2$) method. The double-layered hollow microspheres were manufactured with the yield of 30.92% when the concentration of polymer PBAST in organic phase was 5 wt%, the concentration of PVA in inner aqueous phase was 5 wt%, the volume ratio of $W_1/O$ emulsion to outer aqueous phase was 1:4.5, and when co-surfactants that had large gap in HLB (hydrophile-lipophile balance) value were used. The bulk density of prepared hollow microsphere was 0.180 g/ml and particle size was $1.5{\sim}3\;{\mu}m$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.10a
• /
• pp.691-694
• /
• 2013

This paper has presented the potential distribution for asymmetric double gate(DG) MOSFET, and sloved Poisson equation to obtain the analytical solution of potential distribution. The symmetric DGMOSFET where both the front and the back gates are tied together is three terminal device and has the same current controllability for front and back gates. Meanwhile the asymmetric DGMOSFET is four terminal device and can separately determine current controllability for front and back gates. To approximate with experimental values, we have used the Gaussian function as charge distribution in Poisson equation. The potential distribution has been observed for gate bias voltage and gate oxide thickness and channel doping concentration of the asymmetric DGMOSFET. As a results, we know potential distribution is greatly changed for gate bias voltage and gate oxide thickness, especially for gate to increase gate oxide thickness. Also the potential distribution for source is changed greater than one of drain with increasing of channel doping concentration.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.19 no.2
• /
• pp.401-406
• /
• 2015

The change of subthreshold swing for channel length of asymmetric double gate(DG) MOSFET has been analyzed. The subthreshold swing is the important factor to determine digital chracteristics of transistor and is degraded with reduction of channel. The subthreshold swing for channel length of the DGMOSFET developed to solve this problem is investigated for channel thickness, oxide thickness, top and bottom gate voltage and doping concentration. Especially the subthreshold swing for asymmetric DGMOSFET to be able to be fabricated with different top and bottom gate structure is investigated in detail for bottom gate voltage and bottom oxide thickness. To obtain the analytical subthreshold swing, the analytical potential distribution is derived from Possion's equation, and Gaussian distribution function is used as doping profile. As a result, subthreshold swing is sensitively changed according to top and bottom gate voltage, channel doping concentration and channel dimension.