• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.51-56
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• 2006

Biases embedded in numerical weather precipitation forecasts by the RDAPS model was determined, quantified and corrected. The ultimate objective is to eventually enhance the reliability of reservoir operation by Korean Water Resources Corporation (KOWACO), which is based on precipitation-driven forecasts of stream flow. Statistical post-processing, so called MOS (Model Output Statistics) was applied to RDAPS to improve their performance. The Artificial Neural Nwetwork (ANN) model was applied for 4 cases of 'Probability of Precipitation (PoP) for wet and dry season' and 'Quantitative Precipitation Forecasts (QPF) for wet and dry season'. The reduction on the large systematic bias was especially remarkable. The performance of both networks may be improved by retraining, probably every month. In addition, it is expected that performance of the networks will improve once atmospheric profile data are incorporated in the analysis. The key to the optimal performance of ANN is to have a large data set relevant to the predictand variable. The more complex the process to be modeled by the ANN, the larger the data set needs to be.

• Bulletin of the Korean Mathematical Society
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• v.50 no.5
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• pp.1711-1723
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• 2013

P. V$\acute{a}$mos called a ring R 2-good if every element is the sum of two units. The ring of all $n{\times}n$ matrices over an elementary divisor ring is 2-good. A (right) self-injective von Neumann regular ring is 2-good provided it has no 2-torsion. Some of the earlier results known to us about 2-good rings (although nobody so called at those times) were due to Ehrlich, Henriksen, Fisher, Snider, Rapharl and Badawi. We continue in this paper the study of 2-good rings by several authors. We give some examples of 2-good rings and their related properties. In particular, it is shown that if R is an exchange ring with Artinian primitive factors and 2 is a unit in R, then R is 2-good. We also investigate various kinds of extensions of 2-good rings, including the polynomial extension, Nagata extension and Dorroh extension.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.158.1-158
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• 2001

An algorithmic gray code analog-to-digital converter (ADC), which is based on gray coding, is proposed in this article. The realization method makes use of a MOS triangular function circuit to provide a high-speed operation and low accumulated error. The proposed ADC is simple, small in size and suitable for fabrication using a standard CMOS process. Simulation results showing the performances of the proposed circuit are also included.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.122-125
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• 2004

본 연구는 친환경적 유기흡착제로서 휴믹물질의 활용성을 평가하기 위한 기초 연구로서 Peat moss에서 추출된 불용성 휴믹성분인 피트휴민(p-Humin)을 충진한 컬럼을 이용하여 카드뮴과 구리이온에 대한 파과곡선을 얻었고, 각 금속이온에 대한 제거능을 비교해 보았다. 카드뮴의 경우, 파과시간은 7.5 hr, 77 BV로 나타났으며, 구리의 경우, 7.3 hr, 76 BV으로 나타났다. Thomas model로부터 구한 최대 흡착량은 구리가 44.66 mg/g로 카드뮴의 41.61 mg/g보다 높게 나타났다. 0.05 N HNO$_3$를 이용한 탈질실험 결과, 각 중금속에 대한 회수율은 95% 이상으로 높았다.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.297-300
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• 2005

The characteristics of polycrystalline silicon thin-film transistors (poly-Si TFTs) fabricated using sputter deposited amorphous silicon (a-Si) precursor films are investigated. The a-Si films were deposited on flexible polymer substrates using argon-helium mixture gases to minimize the argon incorporation into the film. The precursor films were then laser annealed by using a XeCl excimer laser and a four-mask-processed poly-Si TFT was fabricated with fully self-aligned top gate structure. The fabricated pMOS TFT showed field-effect mobility of $32.4cm^2/V{\cdot}s$ and on/off ratio of $10^6$.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.22.1-22.1
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• 2009

차세대 CMOS 공정에서 유전상수가 높은 게이트 절연막과 함께 게이트 전극이 관심을 끌고 있다. 게이트 전극은 전도도가 높아야 하고 p-MOS, n-MOS에 맞는 일함수를 가져야 하며 열적 특성이 안정해야 한다. 탄탈룸 계열 탄화물이나 질화물은 게이트 전극으로 관심을 끌고 있는 물질이며 이를 원자층 화학증착법으로 박막화 하는 공정이 관심을 끌고 있다. 원자층 화학공정에서는 전구체의 역할이 중요하며 이의 기상반응 메카니즘, 표면 반응 메카니즘을 제대로 이해해야 한다. 본 연구에서는 TBTDET (tert-butylimido tris-diethylamido tantalum) 전구체의 반응 메커니즘을 FTIR(Fourier Transform Infrared)을 이용해 진단하였다. 또한 수소, 암모니아, 메탄을 이용한 열화학 원자층 증착, 플라즈마 원자층 증착 공정을 수행하여 박막을 얻고 이들의 특성을 평가하였다. 각 공정에 따라 반응 메커니즘이 달라지고 박막의 조성이 달라지며 또한 박막의 물성도 달라진다. 특히 박막에 형성되는 TaC, TaN, Ta3N5, Ta2O5 (증착 후 산소의 유입에 의해 형성됨) 등의 조성이 공정에 따라 달라지며 박막의 물성도 달라진다. 반응메카니즘의 연구를 통해 각 공정에서 어떠한 조성의 박막이 얻어지는 지를 규명하였고 박막의 밀도에 따라 산소유입량이 어떻게 달라지는 지를 규명하였다.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.95-97
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• 2004

본 연구에서는 Scanning Capacitance Microscopy (SCM)와 Electrostatic Force Microscopy (EFM)을 이용하여 국소영역에서 실리콘나노 크리스탈의 전기적 특성을 분석하였다. 실리콘 나노 크리스탈은 에어로솔 방식으로 P-type 실리콘웨이퍼 위에 $10{\sim}40\;nm$의 크기와 약 $10^{11}/cm^2$의 밀도를 갖도록 제작하였다. 실리콘 나노 크리스탈에서 전자와 정공의 trapping 현상은 EFM, SCM 이미지를 통하여 관찰하였고 이러한 나노 크리스탈의 국소영역 특성을 MOS 캐패시터 구조의 C-V 특성을 비교 분석하였다. 또한, 나노 크리스탈에 trapping된 전하의 detrapping 과정을 스트레스 조건에 따라 분석하였다.

• Journal of the Korean Ceramic Society
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• v.31 no.11
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• pp.1330-1336
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• 1994

Ta2O5 films were deposited on the p-Si(100) substrates by ECR-PECVD and annealed in O2 atmosphere. The thicknesses of Ta2O5/SiO2 layers were measured by an ellipsometer and a cross-sectional TEM. Annealing in O2 atmosphere enhanced the stoichiometry of the Ta2O5 film and reduced the impurity carbon content. Ta2O5 films were crystallized at the annealing temperatures above 75$0^{\circ}C$. The best leakage current characteristics and the maximum dielectric constant of Ta2O5/SiO2 film capacitor were observed in the specimen annealed at $700^{\circ}C$ and 75$0^{\circ}C$, respectively. The flat band voltage of the Al/Ta2O5/SiO2/p-Si MOS capacitor was varied in the range of -0.6~-1.6 V with the annealing temperature. The conduction mechanism in the Ta2O5 film, the variation of the effective oxide charge density with the annealing temperature, and the effective electric field distribution in the Ta2O5/SiO2 double layer were also discussed.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.57.1-57.1
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• 2012

We present a spectroscopic study of the globular clusters (GCs) in the giant elliptical galaxy (gE) M86 in the Virgo galaxy cluster. Using the spectra obtained from the Multi-Object Spectroscopy (MOS) mode of Faint Object Camera and Spectrograph (FOCAS) on the Subaru Telescope, we measured the radial velocities of 25 GCs, the metallicities of 16 GCs, and the ages of 8 GCs in M86. The mean velocity and the vocity dispersion of the GCs are < ${\upsilon}_p$ > = -354 ${\pm}$ 80 km/s and ${\sigma}_p$ = 292 ${\pm}$ 32km/s, respectively. The M86 GC system shows some rotation with a large uncertainty and the velocity dispersion of the blue GC system is 60 km/s larger than that of the red GC system. The mean metallicity and age of M86 GCs are <[Fe/H]> = -1.13 ${\pm}$ 0.47 and = 9.7 ${\pm}$ 4.0 Gyr, respectively. We found one GC younger than 5 Gyr. We discuss the spectroscopic results of the M86 GC system in comparison with the GC systems in other gEs.

• The Journal of Korean Physical Therapy
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• v.20 no.1
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• pp.23-31
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• 2008

Purpose: The purpose of this study was finding out the effects of spinal stabilization exercise using Centaur which is a 3D spinal stabilization sports implement on Chronic low back pain patients over 8 weeks. Methods: 30 patients with DDD were observed during the study. Their average age was 66.88years, height was 152.12cm and average weight was 58.91kg, 4 males and 26 females were involved. 8 various investigations were performed and varied values were compared with reinvestigation done after having exercised 8 weeks using 3-D CENTAUR We used VAS(visual analog scale) in order to see the variation of pain intensity, MOI(modified oswestry index) in order to see limitation of daily life. Results: VAS was lessened from 7.57 to 2.63, limitation of routine life(MOS) from 23.48 to 11.30, there were remarkable differences statistically(p<0.05). As a result of muscular investigation for static spinal stabilization by 8 variations of body deflection, muscular strength were all increased and there were signigicant differences statistically(p<0.05). Conclusion: It has turned out that pain and limitation of routine life was lessened, as a result of 8 weeks exercise using CENTAUR, and deep muscular power was increased. Thus it has turned out that 3-D spinal stabilization exercise has an effect on the strengthening spinal muscles and alleviation of their pain for old patients with DDD.