Effects of channel thickness variation on bias stress instability of InGaZnO thin-film transistors

Cho, E.N.,Kang, J.H.,Yun, I. Pergamon Press 2011 Microelectronics reliability Vol.51 No.9

Here, we report on the effects of channel (or active) layer thickness on the bias stress instability of InGaZnO (IGZO) thin-film transistors (TFTs). The investigation on variations of TFT characteristics under the electrical bias stress is very crucial for commercial applications. In this work, the initial electrical characteristics of the tested TFTs with different channel layer thicknesses (40, 50, and 60nm) are performed. Various gate bias (V<SUB>GS</SUB>) stresses (10, 20, and 30V) are then applied to the tested TFTs. For all V<SUB>GS</SUB> stresses with different channel layer thickness, the experimentally measured threshold voltage shift (ΔV<SUB>th</SUB>) as a function of stress time is precisely modeled with stretched-exponential function. It is indicated that the ΔV<SUB>th</SUB> is generated by carrier trapping but not defect creation. It is also observed that the ΔV<SUB>th</SUB> shows incremental behavior as the channel layer thickness increases. Thus, it is verified that the increase of total trap states (N<SUB>T</SUB>) and free carriers resulted in the increase of ΔV<SUB>th</SUB> as the channel layer thickness increases.

The microRNA miR-124 inhibits vascular smooth muscle cell proliferation by targeting S100 calcium-binding protein A4 (S100A4)

Choe, N.,Kwon, D. H.,Shin, S.,Kim, Y. S.,Kim, Y. K.,Kim, J.,Ahn, Y.,Eom, G. H.,Kook, H. Elsevier Science B.V., Amsterdam. 2017 FEBS letters Vol.591 No.7

<P>S100 calcium-binding protein A4 (S100A4) induces proliferation and migration of vascular smooth muscle cells (VSMCs). We aimed to find the microRNA regulating S100A4 expression. S100A4 transcripts are abruptly increased in the acute phase of carotid arterial injury 1 day later (at day 1) but gradually decreases at days 7 and 14. Bioinformatics analysis reveals that miR-124 targets S100A4. VSMC survival is attenuated by miR-124 mimic but increased by miR-124 inhibitor. miR-124 decreases immediately after carotid arterial injury but dramatically increases at days 7 and 14. miR-124 inhibitor-induced cell proliferation is blocked by S100A4 siRNA, whereas miR-124-induced cell death is recovered by S100A4. Our findings suggest that miR-124 is a novel regulator of VSMC proliferation and may play a role in the development of neointimal proliferation.</P>

Contact resistance dependent scaling-down behavior of amorphous InGaZnO thin-film transistors

Cho, E.N.,Kang, J.H.,Yun, I. Elsevier 2011 Current Applied Physics Vol.11 No.4

Here, we report scaling effects on the electrical properties of amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs). The a-IGZO TFTs had same channel width/length ratio (W/L = 20), but different channel lengths (L = 20, 10, 5, and 2.5 μm). To examine the scaling-down behaviors, short-channel effects and contact resistance of the TFTs were investigated. As the channel length decreased, apparent shift of threshold voltage (V<SUB>th</SUB>) and degradation of subthreshold swing (S<SUB>SUB</SUB>) were shown. In addition, it is also found that the field-effect mobility (μ<SUB>FE</SUB>) was degraded as the channel length was decreased which was originated from contact resistance. Due to this contact resistance effect, drain current (I<SUB>DS</SUB>) was decreased for short-channel devices.

Use of Crown Feature Analysis to Separate the Two Pine Species in QuickBird imagery

Choen Kim 大韓遠隔探査學會 2008 大韓遠隔探査學會誌 Vol.24 No.3

Tree species-specific estimates with spacebome high-resolution imagery improve estimation of forest biomass which is needed to predict the long term planning for the sustainable forest management(SFM). This paper is a contribution to develop crown distinguishing coniferous species, Pinus densiflora and Pinus koraiensis, from QuickBird imagery. The proposed feature analysis derived from shape parameters and first and second-order statistical texture features of the same test area were compared for the two species separation and delineation. As expected, initial studies have shown that both formfactor and compactness shape parameters provided the successful differentiating method between the pine species within the compartment for single crown identification from spacebome high resolution imagery. Another result revealed that the selected texture parameters-the mean, variance, angular second moment(ASM)-in the infrared band image could produce good subset combination of texture features for representing detailed tree crown outline.

An Approach to the Spectral Signature Analysis and Supervised Classification for Forest Damages -An Assessment of Low Altitude Airborne MSS Data

Choen Kim 大韓遠隔探査學會 1991 大韓遠隔探査學會誌 Vol.7 No.2

This paper discusses the capabilities of airborne remotely sensed data to detect and classify forest damages. In this work the AMS (Aircraft Multiband Scanner) was used to obtain digital imagery at 300m altitude for forest damage inventory in the Black Forest of Germany. MSS (Multispectral Scanner) digital numbers were converted to spectral emittance and radiance values in 8 spectral bands from the visible to the thermal infrared and submitted to a maximum-likelihood classification for: (1) tree species; and, (2) damage classes. As expected, the results of MSS data with high spatial resolution 0.75m×0.75m enabled the detection and identification of single trees with different damages and were nearly equivalent to the truth information of ground checked data.

조선시대 ㅁ자형 전통가옥의 사랑채와 안채간 동선체계에 관한 연구

천열홍(Choen, Yeol-Hong),김경원(Kim, Kyong-Won),신웅주(Shin, Woong-Ju) 대한건축학회 2013 대한건축학회 학술발표대회 논문집 Vol.33 No.1

고급 사냥감 밀도에 의한 수렵관리 : 김천

Kim, Choen 國民大學校 山林科學硏究所 1994 山林科學 Vol.6 No.-

Wildlife management plays as important roles in multipurpose forest management as sustained yield method emphasizes ecosystem, which is not closed but has both biotic and abiotic components interacting with surrounding systems. Recently hunting is very useful for maintaining biological control rather than as means of sport and recreation. This literature study shows the necessity of hunting stock of nobler beast of venery and higher game birds, hunting care and protection of game, and collecting population data which include the number of individuals.

A Study on Spectral Mixture Analysis of North East China Land-Cover Based on Landsat ETM+Images

Kim, Choen 國民大學校 山林科學硏究所 2005 山林科學 Vol.17 No.-

매년 봄 가을 마다 우리나라에 피해주는 황사는 중국 북동지역의 사막화와 관련이 있다. 본 연구는 Landsat 화상(MSS, TM, ETM+)의 분광혼합분석 기법을 이용하여 토지피복의 사막화 현상을 규명하고자 한다. 기존의 분류방법 대신 분광혼합분석은 나지 및 녹색식생 그리고 수체로 구성된 혼합정도에 따라 각 화소를 세분화한 후 세 계급별, 즉 나지 및 녹색식생 그리고 수체에 대한 분할화상을 생성한다. 분할화상을 통한 결과는 첫째, 나지가 유의하게 증가하는 반면 녹색식생과 수체는 감소하였다. 둘째, 1988년대와 1990년간의 비교보다 1990년대와 2000년대간의 비교에서 사막화가 빠르게 진행되었다. 무엇보다 관개농업이 중국 북동지역의 사막화를 진행시켰다고 볼 수 있다. At every spring, Korean penisular is polluted by the sandy dust blown from China and it reaches a serious level with the annual increase of the blown sand. This study is focused on the change detection of the desertification area in China from 1980s to 2000s, by using multitemporal satellite images(Landsat MSS, TM, and ETM+) based on Spectral Mixture Analysis(SMA) to identify and classify the study area. Endmembers were selected bare soil, green vegetation(GV), and water body by using Minimum Noise Fraction(MNF). Endmembers were also used to generate fraction images from 1980s to 1990s and 1990s to 2000s respectively. From the analysis of multitemporal change detection for three periods, it is apparent that the area of bare soil increased significantly, with simultaneous decrease of GV, and water body. Desertification process from 1990s to 2000s is faster than the period from 1980s to 1990s. The multitemporal fraction images can be effectively used for change detection. Though there is no field survey dataset, SMA gives a reliable result in the change detection of desertification in north-eastern China.

Fuyo-1 OPS 자료를 이용한 낙동강 하류지역의 환경계측 시고

김천 ( Choen Kim ) 大韓遠隔探査學會 1996 大韓遠隔探査學會誌 Vol.12 No.2

본 연구는 낙동강 하류지역의 지속가능한 개발과 환경보전을 위하여 위성탑재 Fuyo-1 OPS VNIR 주사자료에 의한 겨울철 환경계측을 시범·고찰하였다. 따라서 그림자 효과가 강하게 발생하는 산림에 대해 방향성 분광반사특성과 식생지수를 중점분석하고 분광각대응분류를 통하여 겨울철 토지피복도를 산출하였다. 그리고 해·담수 분포도와 낙동강 하류의 수질오염도를 작성하기 위하여 가림기법, 최대우도추정분류기, 그리고 유색밀도편분기법을 응용하였다. 본 연구에서 획득된 결과를 요약하면 첫째로 양지사면의 분광반사치와 식생지수값 모두 음지사면보다 높다. 둘째로 위장반사현상이 일어나는 지역을 주제별 분류를 할 경우 분광각대응 분류 산법이 유용하다. 셋째로 겨울철 낮은 태양고도에도 해·담수분포도를 산출하는데 최대우도추정분류산법이 적합하다. 넷째로 근적외선밴드를 사용하여 가림·유색밀도편분기법에 의해 산출된 수질오염도는 낙동강의 수질상태를 분석할 수 있다. 마지막으로 유색코드 정규식생지수화상은 사면방위에 따른 임관밀도를 파악하는데 이용된다. The objectives of this investigation are: 1. To analyze spectral signature and the associated vegetation index for geometric illumination conditions influenced by low solar elevation and high slope orientations in mountainous forest. 2. To assess the accuracy of the spectral angle mapper classification for the a winter land cover in comparison with the maximum likelihood classification. 3. To produce the image of water quality and water properties that could be used to estimate the water pollution sources and the tide-included by turbid water in estuarine and coastal areas. These objectives are to characterize environmental and ecological monitoring applications of the Nak-Dong River Basin by using Fuyo-1 OPS VNIR data acquired on December 26, 1992. The Results of this paper are as follows: 1. The spectral digital numbers and vegetation indexes (NDVI and TVI) of mountainous forest are higher on the slope facing the sun than on the slope hidden the sun under low sun elevation condition. 2. The spectral angle mapper algorithm produces a more accurate land cover classification of areas with steep slope, various aspects and low solar elevation than the maximum likelihood classifier. 3. The maximum likelihood classification images can be used for identifying the location and movement of both freshwater and salt water, regardless of geometric illumination conditions. 4. The color-coded density sliced image of selected water bodies by using the near-infrared band 3 can provide distribution of the water quality of the Lower Nak-Dong River. 5. The color-coded normalized difference vegetation index image of the selected mountain forest is suitable to classify winter vegetation cover types, i.e., forest canopy densities for slope orientations.

백제 도장(道藏)이 일본 불교에 미친 영향에 대한 기초적 고찰

김천학 ( Choen-hak Kim ) 한국불교사연구소 2016 한국불교사연구 Vol.9 No.-

『성실론소』16권을 저술한 백제 승려 도장(道藏)이 저술은 남아 있지 않고, 일문을 통해서만 알 수 있는데, 다행히 2009년에 1차로 일문을 모아소개가 되었는데, 그 후 후쿠시 지닌 교수에 의해 특히 천태종 문헌에 인용된 일문이 다수 소개되어 진전된 연구가 가능해졌다. 본 고는 그와 같은 기초연구를 통해 『도장소』 일문의 내용을 검토하는 목적으로 서술되었다. 성실종을 일본에 널리 전파한 것은 도장의 공이다. 『성실론』은 삼론종에서 겸학하는 학문이며, 삼론종 승려들이 주로 활용하였다고 기술되어 있다 그런데 이번 후쿠시 교수의 발견으로 천태종에서도 더 많이 연구된 것을 알 수 있었다. 천태종 쇼신(證眞)은 천태삼대부의 『사기』에서 『성실론소』를 30회 정도인용하며 활용한다. 『도장소』가 부정적으로 인용되기도 하지만, 많은 부분 『성실론』의 이해를 위해 『도장소』를 장문에 걸쳐 다용하고 있음도 알수 있었다. 한편, 삼론종 조카이(藏海)의 인용을 통해 도장이 수나라 『명언소』 (明彦疏)를 활용했을 가능성을 제시했으며, 쇼신의 『도장소』 인용으로부터는 도장이 활용한 문헌에 관한 중요한 정보를 알 수 있었다. 즉, 장엄사 승민(莊嚴寺僧旻), 팽성사 숭법사(彭城寺嵩法師), 소장엄사(小莊嚴寺) 혜영(慧榮), 흥업사(興業寺) 승려, 『대승의장』의 인용명을 통해 활용하고 있으며, 그외 남북조시대에 『대지도론소』를 저술한 혜영(慧影), 삼론종 길장, 천태종지의와의 관련도 상정되었다. 이러한 문헌들은 도장이 백제에서 가지고와서 소지하고 있었다고 추정된다. 그러나 본 고에서는 필자의 『성실론』 자체에 대한 지식 부족으로 『도장소』의 내용을 충분히 다루지 못하였다. 향후 도장의 『성실론소』가 인용된 각 문장에 대해서 사상적으로 심도 있게 분석할 필요가 있으며, 논의(교리문답) 등을 통해 더 많은 일문을 찾을 수 있다고 기대한다 Seongsilnon-so(成實論疏) 16volumes - it also named as Dojang-so(道藏疏) - which Ven. Do-jang(道藏) wrote are not remained today. Therefore, just through several quoted sentences in other writer’s works are showed his thought. About these findings, it had been first introduced in 2009, and a lot of loss sentences which had been quoted in works of Tendai sect(天台宗) were introduced by Professor Fukushi-jinin afterwards. A personage who makes Seongsilnon(成實論) spread widely in Nara period were the very Ven. Do-jang. Especially, Shoshin(證眞), the monk of Tendai sect, brought Seongsilnon-so to his writing - Sagi(私記) on Chentaesamdaebu(天台三大部) - approximately 30 times. Much parts of Seongsilnon-so had been quoted in the writing of Shoshin here and there to understand Seongsilnon well. Throughout Shoshin’ quotation, it is able to obtain informations about the documents which Do-jang referred to. At first, he utilized the works of Ven. Sengmin on Zhangyansi (莊嚴寺僧旻), Ven. Songfashi on Pengchegsi (彭城寺嵩法師), Ven. Huirong on XiaoZhangyansi (小莊嚴寺慧榮), the monk of Xingyesi(興業寺), and the text of Dachengyizhang(大乘義章). And it might sugested that he take the writings of Ven. Huiying(慧影), Ven. Mingyan(明彦), Ven. Jizang(吉藏), Ven. Zhiyi(智의) into his account. Also, it is estimated that these quoted documents were bought from Baekje. To my regret, lack of my knowledge on Seongsilnon, it was not sufficiently considered. therefore, I hope that it will be deeply treated more in future.