• 제목/요약/키워드: Cho Ji-hoon

검색결과 707건 처리시간 0.031초

Highly Crystalline 2,6,9,10-Tetrakis((4-hexylphenyl)ethynyl)anthracene for Efficient Solution-Processed Field-effect Transistors

  • Hur, Jung-A;Shin, Ji-Cheol;Lee, Tae-Wan;Kim, Kyung-Hwan;Cho, Min-Ju;Choi, Dong-Hoon
    • Bulletin of the Korean Chemical Society
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    • 제33권5호
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    • pp.1653-1658
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    • 2012
  • A new anthracene-containing conjugated molecule was synthesized through the Sonogashira coupling and reduction reactions. 1-Ethynyl-4-hexylbenzene was coupled to 2,6-bis((4-hexylphenyl) ethynyl)anthracene-9,10-dione through a reduction reaction to generate 2,6,9,10-tetrakis((4-hexylphenyl)ethynyl) anthracene. The semiconducting properties were evaluated in an organic thin film transistor (OTFT) and a single-crystal field-effect transistor (SC-FET). The OTFT showed a mobility of around 0.13 $cm^2\;V^{-1}\;s^{-1}$ ($I_{ON}/I_{OFF}$ > $10^6$), whereas the SC-FET showed a mobility of 1.00-1.35 $cm^2\;V^{-1}\;s^{-1}$, which is much higher than that of the OTFT. Owing to the high photoluminescence quantum yield of 2,6,9,10-tetrakis((4-hexylphenyl)ethynyl) anthracene, we could observe a significant increase in drain current under irradiation with visible light (${\lambda}$ = 538 nm, 12.5 ${\mu}W/cm^2$).

유전자 발현 데이터를 이용한 암의 유형 분류 기법 (Cancer-Subtype Classification Based on Gene Expression Data)

  • 조지훈;이동권;이민영;이인범
    • 제어로봇시스템학회논문지
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    • 제10권12호
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    • pp.1172-1180
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    • 2004
  • Recently, the gene expression data, product of high-throughput technology, appeared in earnest and the studies related with it (so-called bioinformatics) occupied an important position in the field of biological and medical research. The microarray is a revolutionary technology which enables us to monitor several thousands of genes simultaneously and thus to gain an insight into the phenomena in the human body (e.g. the mechanism of cancer progression) at the molecular level. To obtain useful information from such gene expression measurements, it is essential to analyze the data with appropriate techniques. However the high-dimensionality of the data can bring about some problems such as curse of dimensionality and singularity problem of matrix computation, and hence makes it difficult to apply conventional data analysis methods. Therefore, the development of method which can effectively treat the data becomes a challenging issue in the field of computational biology. This research focuses on the gene selection and classification for cancer subtype discrimination based on gene expression (microarray) data.

HyTime 문서의 객체지향 모델링 (An Object-Oriented Modeling of HyTime Documents)

  • 강지훈;조영환;박천수
    • 정보교육학회논문지
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    • 제4권2호
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    • pp.223-231
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    • 2001
  • 하이퍼미디어 문서들은 문서의 구조 정보를 포함하고 있다. 이러한 구조 정보를 이용하여 하이퍼미디어 문서를 저장, 검색하기 위한 모델에 관한 연구가 있어 왔다. 그러나 실제 문서의 상연을 지원하기 위한 모델의 제시가 미비한 실정이다. 본 논문에서는 HyTime 하이퍼미디어 문서를 문서의 구조정보를 이용하여 객체지향 모델링을 하여 상연을 효율적으로 수행할 수 있는 방안을 제안한다. 이를 위하여 HyTime의 응용으로 사용자의 요구에 맞게 뉴스를 제공하는 주문형 뉴스 서비스를 지원하는 시스템을 고려한다. 본 논문에서 제안한 모델링은 주문형 뉴스 서비스뿐만 아니라, 멀티미디어를 지원하는 주문형 웹 기반 교육, 디지털 도서관 등의 하이퍼미디어 응용 분야에서 활용될 수 있을 것이다.

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Optical diffraction gratings embedded in BK-7 glasses by tightly focused femtosecond laser

  • Yoon, Ji Wook;Choi, Won Suk;Kim, Hoon Young;Cho, Sung-Hak
    • 한국레이저가공학회지
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    • 제17권2호
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    • pp.19-25
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    • 2014
  • Optical embedded diffraction gratings with the bulk modification in BK-7 glass plates excited by tightly focused high-intensity femtosecond (130fs) Ti: sapphire laser (peak wavelength = 790nm) were demonstrated. The structural modifications with diameters ranging from 400nm to $4{\mu}m$ were photo-induced after plasma formation occurred upon irradiation with peak intensities of more than $1{\times}1013W/cm^2$. The graded refractive index profile was fabricated to be a symmetric around from the center of the point at which low-density plasma occurred. The maximum refractive index change was estimated to be $1.5{\times}10^{-2}$. The two optical embedded gratings in BK-7 glass plate were demonstrated with refractive index modification induced by the scanning of low-density plasma formation.

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Accelerating Self-Similarity-Based Image Super-Resolution Using OpenCL

  • Jun, Jae-Hee;Choi, Ji-Hoon;Lee, Dae-Yeol;Jeong, Seyoon;Cho, Suk-Hee;Kim, Hui-Yong;Kim, Jong-Ok
    • IEIE Transactions on Smart Processing and Computing
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    • 제4권1호
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    • pp.10-15
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    • 2015
  • This paper proposes the parallel implementation of a self-similarity based image SR (super-resolution) algorithm using OpenCL. The SR algorithm requires tremendous computations to search for a similar patch. This becomes a bottleneck for the real-time conversion from a FHD image to UHD. Therefore, it is imperative to accelerate the processing speed of SR algorithms. For parallelization, the SR process is divided into several kernels, and memory optimization is performed. In addition, two GPUs are used for further acceleration. The experimental results shows that a GPGPU implementation can speed up over 140 times compared to a single-core CPU. Furthermore, it was confirmed experimentally that utilizing two GPUs can speed up the execution time proportionally, up to 277 times.

Malignant Mesothelioma Presenting as Large Neck Mass

  • Lee, Bae Young;Kim, Hyeon Sook;Song, Kyung Sup;Cho, Song Mee;Lee, Kang Hoon;Choi, Jung Eun;Lee, Sang Haak;Moon, Hwa Sik;Kang, Ji Young;Kang, Hyun Hee;Min, Ki Ouk
    • Tuberculosis and Respiratory Diseases
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    • 제67권4호
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    • pp.369-373
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    • 2009
  • Malignant mesothelioma is the most common primary malignant tumor involving pleura, but its diagnosis is difficult to determine by pathology in addition to the fact that it is rare. We present an unusual case of malignant mesothelioma, which initially presented as large neck mass contrary to the more common presentation of a rind like growth along the pleura demonstrated on imaging and by pathologic findings.

서브마이크론 입자 측정용 저압 임팩터의 설계 및 성능평가 (Design and Performance Evaluation of a Low Pressure Impactor for Sampling Submicron Aerosols)

  • 지준호;조명훈;배귀남;황정호
    • 대한기계학회논문집B
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    • 제28권3호
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    • pp.349-358
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    • 2004
  • A low pressure impactor is an impaction device to separate airborne particles into aerodynamic size classes at low pressure condition. We designed a two-stage low-pressure impactor to classify submicron sized environmental aerosols. Performance evaluation was carried out for stages 1 and 2 by using an electrical method. Monodisperse liquid dioctyl sebacate (DOS) particles were generated using evaporation-condensation process followed by electrostatic classification using a DMA (differential mobility analyzer). The test particles were in the range of 0.08∼0.8$\mu\textrm{m}$. For the evaluation of the impactor we used two electrometers; one was connected to the impaction plate of the impactor and the other was to the Faraday cage used as a backup filter. The effect of polydispersity of test aerosols on the performance was investigated. The results showed that the experimental 50-% cutoff diameters at each impactor's operation pressure were 0.53 and 0.187$\mu\textrm{m}$ for stages 1 and stage 2, respectively. The effects of operation pressure on the cutoff diameter and the steepness of collection efficiency curves were also investigated.

Study on the characteristics of white organic light-emitting diodes using a new material

  • Shim, Hye-Yeon;Jeong, Ji-Hoon;Kwon, Hyuk-Joo;Cho, Young-Jun;Kim, Bong-Ok;Kim, Sung-Min;Kim, Chi-Sik;Yoon, Seung-Soo;Kim, Young-Kwan
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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    • pp.688-691
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    • 2004
  • In this study, we synthesized a new red emitting material of a Red225 doped into $Alq_3$ (tris(8-quinolinolato)aluminum (III)) and fabricated white organic light-emitting diodes (OLEDs) with a simple device structure. With a blue emitting material of DPVBi (4,4'-bis(2,2'-diphenylvinyl)1,1'-biphenyl) that can transfer effectively both a hole and an electron, OLEDs with a narrow emission layer could be possible without a hole-blocking layer. Consequently, the driving voltage and stability of devices have been improved. The devices show the Commission Internationale d'Eclairage (CIE) chromaticity coordinates of (0.36, 0.35) at luminance of 2000 cd/$m^2$. The luminous efficiency is about 3.5 cd/A, luminance is about 12000 cd/$m^2$ and current density is about 350 mA/$cm^2$ at 12 V, respectively.

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Identification and Detection of Streptococcus anginosus Using Species-Specific 16S rDNA Primers

  • Cho, Ji-Sun;Yoo, So-Young;Kim, Hwa-Sook;Hwang, Ho-Keel;Min, Jeong-Beom;Kim, Byung-Hoon;Baek, Dong-Heon;Shin, Hwan-Seon;Kook, Joong-Ki
    • International Journal of Oral Biology
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    • 제31권1호
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    • pp.11-14
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    • 2006
  • This study was undertaken to develop PCR primers for the identification and detection of Streptococcus anginosus using species-specific forward and reverse primers. These primers targeted the variable regions of the 16S ribosomal RNA coding gene(rDNA). The primer specificity was tested against 12 S. anginosus strains and 6 different species(10 strains) of oral bacteria. The primer sensitivity was determined by testing serial dilutions of the purified genomic DNA of S. anginosus ATCC $33397^T$. The data showed that species-specific amplicons were obtained from all the S. anginosus strains tested, but not in the six other species. The PCR could detect as little as 0.4pg of the chromosomal DNA from S. anginosus. This suggests that the PCR primers are highly sensitive and applicable to the detection and identification of S. anginosus.

병원의 정보시스템 도입 특성과 조직성과간의 관계에 있어 정보화 수준의 매개 효과 (The mediating effect of informatization level between characteristics of introducing information system and organizational performance in hospital settings)

  • 지재훈;조영하
    • 한국병원경영학회지
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    • 제17권3호
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    • pp.1-22
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    • 2012
  • The purpose of this study is to analyze the mediating effect of informatization level between characteristics of introducing information system and organizational performance in hospital settings, and to provide suggestions to improve the performance level of strategic information system of hospitals. In order to achieve study purpose, a causal path model was developed and empirically tested. Data were collected from 746 managers of 92 hospitals keeping information system in Busan, Ulsan and Kyungnam Province using self-administered structured questionnaire. Major results of this study were as follows; The results of the path analysis showed that organizational characteristics variables except informatization strength within health industry had significant effects on informatization level, and had indirect effects on organizational performance mediated by informatization level. On the other hand, informatization level, especially revelation capability among informatization level variables, was found to have significant direct effect on organizational performance. These results of empirical test imply that informatization level variables are both important affecting factors on organizational performance and mediating factors between organizational characteristics and organizational performance. Therefore, in order to increase organizational performance, measures improving informatization level should be developed and carried out continuously. And, especially, focusing on building and strengthening revelation capability is crucial to those efforts.

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