• Title/Summary/Keyword: Cho, Hyun Myung

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A study on characteristic transmission-reflection by environmental change of solar cell (태양전지셀의 환경변화에 따른 투과-반사특성 연구)

  • Shin, Sang-Wuk;Lee, Se-Hyun;Cho, Mee-Ryoung;Hwang, Myung-Keun
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.06a
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    • pp.233-236
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    • 2006
  • In this paper, I try to measure characteristic transmission-reflection by environmental change or solar cell. I keep my eye on the characteristics variation of solar cell as environmental change. As a result, A variation caused by voltage by an effect on the efficiency of solar PV cell. Hence, it is an important variable when a designer plan to make a solar cell.

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Pre-layout Clock Analysis with Static Timing Analysis Algorithm to Optimize Clock Tree Synthesis (Static Timing Analysis (STA) 기법을 이용한 Clock Tree Synthesis (CTS) 최적화에 관한 연구)

  • Park, Joo-Hyun;Ryu, Seong-Min;Jang, Myung-Soo;Choi, Sea-Hawon;Choi, Kyu-Myung;Cho, Jun-Dong;Kong, Jeong-Taek
    • Proceedings of the KIEE Conference
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    • 2004.11c
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    • pp.391-393
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    • 2004
  • For performance and stability of a synchronized system, we need an efficient Clock Tree Synthesis(CTS) methodology to design clock distribution networks. In a system-on-a-chip(SOC) design environment, CTS effectively distributes clock signals from clock sources to synchronized points on layout design. In this paper, we suggest the pre-layout analysis of the clock network including gated clock, multiple clock, and test mode CTS optimization. This analysis can help to avoid design failure with potential CTS problems from logic designers and supply layout constraints so as to get an optimal clock distribution network. Our new design flow including pre-layout CTS analysis and structural violation checking also contributes to reduce design time significantly.

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Implementation of Multi-Channel Power Components Measuremen System (다채널 전력분석시스템의 구현)

  • Lee, Myung-Un;Yoo, Jae-Geun;Lee, Sang-Ick;Cho, Myung-Hyun;Choe, Gyu-Ha
    • The Transactions of the Korean Institute of Power Electronics
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    • v.11 no.3
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    • pp.233-238
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    • 2006
  • In order to solve power disturbances, power components measurement for both supply and demand side of power system must be implemented. This paper proposed a DSP (Digital Signal Processor)-based multi-channel (voltage 8-channel and current 10-channel) power components measurement system that simultaneously can measure and analyze power components for both supply md demand side. After voltage and current measurement accuracy revision using YOKOGAWA 2558, the developed system was tested in the field.

A Study on the Implementation of Inheritance Anomaly in Concurrent Programming (병행 프로그래밍에서 상속 이상의 구현에 관한 연구)

  • Cho, Myung-Hyun;Lee, Myung-Un
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.54 no.1
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    • pp.53-57
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    • 2005
  • When concurrency is integrated to programming language, problem more than inheritance remains yet. Because more than inheritance happens by collision or cross fire between synchronization and inheritance of same time object, when synchronization code is not detached properly from method code about same time object, it makes expanded of code to make derivation class change synchronization code of super class and method code. In this paper, minimize right of inheritance method, When subclass is introduced to new synchronization limitation condition, wish to solve problem more than inheritance of three types that happen in same time programming embodying C++ class that do so that can avoid alteration of method reed.

Determination of Niflumic Acid in Human Urine by Gas Chromatography/Negative Chemical lonization Mass Spectrometry

  • Myung, Seung-Woon;Kim, Myung-Soo;Cho, Hyun-Woo;Park, Jong-Sei
    • Archives of Pharmacal Research
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    • v.19 no.6
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    • pp.566-569
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    • 1996
  • A sensitivity method has been developed for the detection and determination of niflmic acid(NA) in human urine. Samples were extracted with diethylether. Flunixin (FN) was added to the sample prior to extraction as an internal standard. Niflumic acid was converted to its methyl derivative and analyzed by capillary gas chromatography/negative chemical isonization mass spectrometry. Using selected ion monitoring (SIM), the levels of NA down to 5 pg/ml could be detected in 5 ml spiked urine sample. Calibration curve was linear over the range of 0.5 ppm-50 ppm. The recovery of niflumic acid from urine at 40 pg/ml was to be $91.7{\pm}3.8(n=3)$ and the coefficient of variation was 4.1%.

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Efficient Modifications of Cubic Convolution Interpolation Based on Even-Odd Decomposition (짝수 홀수 분해법에 기초한 CCI의 효율적인 변형)

  • Cho, Hyun-Ji;Yoo, Hoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.5
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    • pp.690-695
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    • 2014
  • This paper presents a modified CCI image interpolation method based on the even-odd decomposition (EOD). The CCI method is a well-known technique to interpolate images. Although the method provides better image quality than the linear interpolation, its complexity still is a problem. To remedy the problem, this paper introduces analysis on the EOD decomposition of CCI and then proposes a reduced CCI interpolation in terms of complexity, providing better image quality in terms of PSNR. To evaluate the proposed method, we conduct experiments and complexity comparison. The results indicate that our method do not only outperforms the existing methods by up to 43% in terms of MSE but also requires low-complexity with 37% less computing time than the CCI method.

Clinical Applications of 3T MR Spectroscopy

  • Choe, Bo-Young;Baik, Hyun-Man;Chu, Myung-Ja;Jeun, Sin-Soo;Kang, Sei-Kwon;Chung, Sung-Taek;Park, Chi-Bong;Oh, Chang-Hyun;Lee, Hyoung-Koo
    • Proceedings of the Korean Society of Medical Physics Conference
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    • 2002.09a
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    • pp.345-351
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    • 2002
  • The purpose of this study was to assess clinical proton MR spectroscopy (MRS) as a noninvasive method for evaluating brain tumor malignancy at 3T high field system. Using 3T MRI/MRS system, localized water-suppressed single-voxe1 technique in patients with brain tumors was employed to evaluate spectra with peaks of N-acetyl aspartate (NAA), choline-containing compounds (Cho), creatine/phosphocreatine (Cr) and lactate. On the basis of Cr, these peak areas were quantificated as a relative ratio. The variation of metabolites measurements of the designated region in 10 normal volunteers was less than 10%. Normal ranges of NAA/Cr and Cho/Cr ratios were 1.67${\pm}$018 and 1.16${\pm}$0.15, respectively. NAA/Cr ratio of all tumor tissues was significantly lower than that of the normal tissues (p=0.005), but Cho/Cr ratio of all tumor tissue was significantly higher (p=0.001). Cho/Cr ratio of high-grade gliomas was significantly higher than that of low-grade gliomas (P=0.001). Except 4 menigiomas, lactate signal was observed in all tumor cases. The present study demonstrated that the neuronal degradation or loss was observed in all tumor tissues. Higher grade of brain tumors was correlated with higher Cho/Cr ratio, indicating a significant dependence of Cho levels on malignancy of gliomas. Our results suggest that clinical proton MR spectroscopy could be useful to predict tumor malignancy.

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Preparation and Permeation Characteristics of PDMS-b-PMMA Copolymer Membrane (PDMS-b-PMMA 공중합체 막의 제조 및 투과특성)

  • Kang, Tae-Beom;Cho, A-Ra;Lee, Hyun-Kyung
    • Membrane Journal
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    • v.18 no.3
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    • pp.219-225
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    • 2008
  • In this research, polydimethylsiloxane-polymethylmethacrylate (PDMS-PMMA) block copolymer was synthesized from polydimethylsiloxane (PDMS) and methylmethacrylate (MMA) monomer using atom transfer radical polymerization (ATRP). The synthesis characterization of the PDMS-b-PMMA copolymer membrane was carried out by a FT-IR, $^1H$-NMR, GPC and DSC. The permeabilities of nitrogen and hydrogen gases were observed being $1.2{\sim}l.5$ barrer and $6.2{\sim}10.5$ barrer, respectively. Simultaneously, selectivities of hydrogen against nitrogen were $5.3{\sim}6.9$. The permeability and selectivity of PDMS-b-PMMA copolymer membrane were showed lower than the PDMS membrane, but higher than the PMMA membrane.