Vertically-stacked LEDs with invariance of color Chromaticity

후이,K.S. Hui 한국물리학회 2011 Current Applied Physics Vol.11 No.3

This study investigated the variance of color chromaticity of a vertically-stacked LEDs device with respect to the viewing angles. The LED chips with truncated inverted pyramid geometry were fabricated by laser micromachining. The sidewalls of the truncated inverted pyramid LED chips were coated with a thin layer of highly reflective silver film. The red, green and blue truncated inverted pyramid LED chips were vertically-stacked to form the white LEDs with color tunable function. A well mix of colors from the polychromatic LED chips was achieved in the layout of the vertically-stacked LEDs without utilizing additional optics. Compared to the commercial RGB LEDs, the stacked LEDs device showed insignificant angular dependence of color chromaticity. A luminous efficacy of 33 lm/W was achieved without any optimization of the fabrication process.

Industrial Cluster-Based Policies in Korea: Implications for Vietnam

후이,김준엽 국제지역학회 2015 국제지역연구 Vol.19 No.2

This paper analyzes the cluster-based policies to improve firms’ innovation capacity by promoting business-academia networks, shifting industrial complexes to clusters in South Korea. By analyzing these policies, the paper presents that government’s role is supportive in forming clusters in Korea. Also, the paper examines the initial outcomes of cluster development under government policies. By using Shift-share and Location Quotient analyses, Changwon Mechanical Engineering Cluster is quantitatively analyzed as an example of contribution of cluster to industrial concentration and competitiveness in regional economy under government policies. Also these analyses are applied to Dongnai province of Vietnam to understand the current stage of complex development and make comparison between Korea and Vietnam. Finally, policy implications to promote industrial clusters are drawn for Vietnam from Korea’s experience.

잉크호텔

토비아스 코흐(Tobias Koch),에워트 후이버스(사진),미첼 반 부르베르헌(사진) 현대건축사 2016 마루 Vol.- No.168

잉크호텔

토비아스 코흐(Tobias Koch),에워트 후이버스(사진),미첼 반 부르베르헌(사진) 현대건축사 2016 (월간)Maru Vol.168 No.-

아민이 기능화된 ZIF-8를 이용한 이산화탄소 선택적 흡착 연구

후이 도 쑤언,이유리,백경열,안희성,이종석 한국막학회 2018 한국막학회 총회 및 학술발표회 Vol.2018 No.11

본 연구에서는 후처리 기능화를 통해 아민이 함유된 ZIF-8-A를 제조하고, 이를 이산화탄소 흡착제로 적용하였다. 첨가한 3-amino-1,2,4-triazole의 함량에 따라 15, 37, 61, 그리고 74 %의 아민기를 포함한 ZIF-8-A를 제조하였으며, 다양한 분석을 통해 이들의 물성특성을 조사하였다. 그 결과, 아민 함량에 따라 ZIF-8-A의 게이트 크기 조절되고 가스 투과도 및 선택도에 영향을 미치는 것을 확인하였다. ZIF-8-A61%는 기존 ZIF-8 대비 CO2/N2 및 CO2/CH4에 대한 선택도가 3.4 및 4.7배 증가하였으며, 이는 구조내 가스 투과를 위한 게이트 사이즈의 조절 및 아민과 이산화탄소의 상호작용에 기인한 것으로 판단하였다.

스케일 불변 특징들의 분포를 이용한 장소의 모델링 및 인식

후이(Yi Hu),신범주(Bum Joo Shin),이창우(Chang Woo Lee) 한국컴퓨터정보학회 2008 韓國컴퓨터情報學會論文誌 Vol.13 No.4

본 논문에서 스케일 불변 특징 분포를 이용한 장소 모델링과 실제 입력되는 특징을 추출하여 데이터베이스에 저장된 장소모델을 비교하여 장소를 인식하는 방법을 제안한다. 제안된 방법에서 모든 장소는 각각 다른 장소와 확실히 구별되는 고유한 특징들의 분포로 표현 가능하다고 가정한다. 제안된 방법은 각 장소마다 전역정보를 사용하며, 하나의 장소는 하나의 장소모델로 표현된다. 따라서 장소의 인식을 위해 비교 대상이 되는 장소의 수가 증가하여도, 장소인식을 위한 시간의 복잡도가 기하급수적으로 증가하지 않는다는 장점을 가진다. 제안된 방법의 성능을 검증하기 위한 실험으로 인식에 사용된 특징의 수와 입력영상의 수를 변화시키며 실험을 수행하였고, 실험을 통해 기존의 방법보다 공간적, 시간적인 면에서 제안된 방법이 효율적임을 입증하였다. 제안된 방법은 로봇의 자율항해, 시각장애인의 도움이 시스템, 웨어러블 컴퓨팅 분야 등, 다양한 분야에 활용도가 있으리라 기대한다. In this paper, we propose a place modeling based on the distribution of scale-invariant features, and a place recognition method that recognizes places by comparing the place model in a database with the extracted features from input data. The proposed method is based on the assumption that every place can be represented by unique feature distributions that are distinguishable from others. The proposed method uses global information of each place where one place is represented by one distribution model. Therefore, the main contribution of the proposed method is that the time cost corresponding to the increase of the number of places grows linearly without increasing exponentially. For the performance evaluation of the proposed method, the different number of frames and the different number of features are used, respectively. Empirical results illustrate that our approach achieves better performance in space and time cost comparing to other approaches. We expect that the proposed method is applicable to many ubiquitous systems such as robot navigation, vision system for blind people, wearable computing, and so on.

가스하이드레이트 탄성파 자료의 복소분석

도안 후이 히엔(Hien, D.H.),장성형(Jang, Seong-Hyung),김영완(Kim, Young-Wan),서상용(Suh, Sang-Yong) 한국신재생에너지학회 2008 한국신재생에너지학회 학술대회논문집 Vol.2008 No.10

Gas hydrate has been paid attention to study for because: 1) it can be considered as a new energy resources; 2) one of reasons causing the instability of sea floor slope and 3) a factor to the climate change. Bottom simulating reflector (BSR) defined as seismic boundary between the gas hydrate and free gas zone has been considered as the most common evidence in the seismic reflection data for the gas hydrate exploration. BSR has several characteristics such as parallel to the sea bottom, high amplitude, reducing interval velocity between above and below BSR and reversing phase to the sea bottom. Moreover, instantaneous attribute properties such as amplitude envelop, instantaneous frequency, phase and first derivative of amplitude of seismic data from the complex analysis could be used to analyze properties of BSR those would be added to the certain properties of BSR in order to effectively find out the existence of BSR of the gas hydrate stability zone. The output of conventional seismic data processing for gas hydrate data set in Ulleung basin in the East sea of Korea will be used for complex analyses to indicate better BSR in the seismic reflection data. This result of this analysis implies that the BSR of the analyzed seismic profile is clearly located at the two ways time (TWT) of around 3.1 seconds.

탄성파 반사 신호 향상

도안 후이 히엔(Hien, D.H.),장성형(Jang, Seong-Hyung),김영완(Kim, Young-Wan),서상용(Suh, Sang-Yong) 한국신재생에너지학회 2008 한국신재생에너지학회 학술대회논문집 Vol.2008 No.05

Deconvolution is one of the most used techniques for processing seismic reflection data. It is applied to improve temporal resolution by wavelet shaping and removal of short period reverberations. Several deconvolution algorithms such as predicted, spike, minimum entropy deconvolution and so on has been proposed to obtain such above purposes. Among of them, iota_1 norm proposed by Taylor et al., (1979) and used to compared to minimum entropy deconvolution by Sacchi et al., (1994) has given some advantages on time computing and high efficiency. Theoritically, the deconvolution can be considered as inversion technique to invert the single seismic trace to the reflectivity, but it has not been successfully adopted due to noisy signals of the real data set and unknown source wavelet. After stacking, the seismic traces are moved to zero offset, thus each seismic traces now can be a single trace that is created by convolving the seismic source wavelet and reflectivity. In this paper, the fundamental of iota_1 norm deconvolution method will be introduced. The method will be tested by synthetic data and applied to improve the stacked section of gas hydrate.

왕은 없다

응우옌 후이 티엡 인천작가회의(작가들) 2017 작가들 Vol.- No.60

가스 하이드레이트 자료에 대한 중합전 키르히호프 심도 구조보정

도안 후이 히엔(Hien, Doan Huy),장성형(Jang, Seong-Hyung),김영완(Kim, Young-Wan),서상용(Suh, Sang-Yong) 한국신재생에너지학회 2007 한국신재생에너지학회 학술대회논문집 Vol.2007 No.06

Korean Institute of Geosciences and Mineral Resources (KIGAM) has studied on gas hydrate in the Ulleung Basin, East sea of Korea since 1997. Most of all, a evidence for existence of gas hydrate, possible new energy resources, in seismic reflection data is bottom simulating reflection (BSR) which parallel to the sea bottom. Here we conducted the conventional data processing for gas hydrate data and Kirchhoff prestack depth migration. Kirchhoff migration is widely used for pre- and post-stack migration might be helpful to better image as well as to get the geological information. The processed stack image by GEOBIT showed some geological structures such as faults and shallow gas hydrate seeping area indicated by strong BSR. The BSR in the stack image showed at TWT 3.07s between shot gather No 3940 to No 4120. The estimated gas seeping area occurred at the shot point No 4187 to No 4203 and it seems to have some minor faults at shot point No 3735, 3791, 3947 and 4120. According to the result of depth migration, the BSR showed as 2.3km below the sea bottom.