• Nanomaterials
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• v.12 no.11
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• pp.1808-1817
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• 2022

A machine-learning (ML) technique was used to optimize the energetic-trap distributions of nano-scaled charge trap nitride (CTN) in 3D NAND Flash to widen the threshold voltage (V_th) window, which is crucial for NAND operation. The energetic-trap distribution is a critical material property of the CTN that affects the V_th window between the erase and program V_th. An artificial neural network (ANN) was used to model the relationship between the energetic-trap distributions as an input parameter and the V_th window as an output parameter. A well-trained ANN was used with the gradient-descent method to determine the specific inputs that maximize the outputs. The trap densities (N_TD and N_TA) and their standard deviations (σ_TD and σ_TA) were found to most strongly impact the V_th window. As they increased, the V_th window increased because of the availability of a larger number of trap sites. Finally, when the ML-optimized energetic-trap distributions were simulated, the V_th window increased by 49% compared with the experimental value under the same bias condition. Therefore, the developed ML technique can be applied to optimize cell transistor processes by determining the material properties of the CTN in 3D NAND Flash.

• Progress in Medical Physics
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• v.26 no.1
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• pp.6-11
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• 2015

The purpose of this study was to analyze the rotational errors of roll, pitch, and yaw in the whole breast cancer treated by the three-dimensional radiation therapy (3D-CRT) using TomoDirect (TD). Twenty-patient previously treated with TD 3D-CRT was selected. We performed a retrospective clinical analysis based on 80 images of megavoltage computed tomography (MVCT) including the systematic and random variation with patient setup errors and treatment setup margin (mm). In addition, a rotational error (degree) for each patient was analyzed using the automatic image registration. The treatment margin of X, Y, and Z directions were 4.2 mm, 6.2 mm, and 6.4 mm, respectively. The mean value of the rotational error for roll, pitch, and yaw were $0.3^{\circ}$, $0.5^{\circ}$, $0.1^{\circ}$, and all of systematic and random error was within $1.0^{\circ}$. The errors of patient positioning with the Y and Z directions have generally been mainly higher than the X direction. The percentage in treatment fractions in less than $2^{\circ}$ at roll, pitch, and yaw are 95.1%, 98.8%, and 97.5%, respectively. However, the edge of upper and lower (i.e., bottom) based on the center of therapy region (point) will quite a possibility that it is expected to twist even longer as the length of treatment region. The patient-specific characters should be considered for the accuracy and reproducibility of treatment and it is necessary to confirm periodically the rotational errors, including patient repositioning and repeating MVCT scan.

• Phonetics and Speech Sciences
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• v.16 no.3
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• pp.59-69
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• 2024

Among the subgroups of speech sound disorder (SSD), the motor speech disorder (MSD) group is characterized by weak articulatory force. This study quantitatively measured and compared articulatory muscle strength between SSD and typically developing (TD) children. The Iowa Oral Performance Instrument (IOPI) was used to measure lip and tongue strength in 15 children with SSD and 15 TD children. We additionally measured peak lip and tongue pressure and endurance, and analyzed the correlation between each strength measure and the percentage of consonants correct (PCC). The findings were as follows: First, lip strength for the bilabial sounds did not differ between the two groups in the initial position but was significantly weaker in the SSD group in the final position. Tongue strength for alveolar sounds was weaker in the SSD group than in the TD group for the initial and final positions. Second, for lip and tongue strength, the difference in voicing features was significant in the TD group but not in the SSD group. Third, the peak pressure and endurance of the lips and tongue were significantly lower in the SSD group than in the TD group. Fourth, significantly higher static correlations were observed between most strength measures and the PCC. These findings suggest that weakness in articulatory motor execution may be an unrecognized underlying problem of SSD with unknown origin.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1481_1482
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• 2009

Pure Xe, Kr and Ne atoms and Mixures of Xe-Ne used in fluorescent induction lamps(FILs). However standard regulation of FILs is not made up until now. Therefore, the electron transport coefficients, the electron drift velocity W, the longitudinal diffusion coefficient NDL and the ionization coefficient $\alpha$/N in pure Xe, Kr, Ne gases and Xe-Ne mixtures(1:9, 5:5, 7:3) were calculated over the wide E/N range from 0.01 to 500 Td at 1 Torr by two-term approximation of the Boltzman equation.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.369-370
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• 2008

본 논문은 TD-PS(Time Delay-Phase Shift) 방식 다중 3-Level NPC 인버터의 출력에 포함된 미소 직류 전압 억제 및 직류버스의 정/부 콘덴서 전압의 불평형 개선 방안과 그 효과에 대하여 기술하였다.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2002.11a
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• pp.1-18
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• 2002

우리나라는 매년 3∼4개의 태풍의 영향을 받고 있다. 금년에는 현재까지 4개의 태풍(제5호 라마순, 제8호 나크리, 제9호 펑셴, 제15호 루사)의 영향을 받았다. 특히, 태풍 역사이래 최대의 재산 및 인명 피해를 유발한 제15호 태풍은 8월 23일 09시경 북태평양의 괌 동북동쪽 약 1,800km 부근 해상(16.5N, 161.0E)에서 열대저압부(Tropical Depression, TD)가 '약'한 '소형' 열대폭풍(Tropical Storm, TS)으로 조직화되면서 제15호 태풍 '루사(RUSA)'로 명명되었으며, 그 뜻은 '삼바사슴'을 의미하고 말레이시아에서 제출한 태풍 이름이다.(중략)

• Archives of Pharmacal Research
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• v.15 no.3
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• pp.204-207
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• 1992

Glycylglycine, alanylalanine and alanylglycine were synthesized, their free carboxylic and amino groups were converted to methyl esters of N-acetylglycyglycine, N-acetylalanylglycine and N-acetylalanylalanine. The synthesized compounds were evaluated for antiepileptic activity, plasmaprotein binding, $TD_{50}$ and potentiating effect of phenobarbitone sodium.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.304-309
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• 2008

기존의 태풍예측과 관련된 연구들은 전 지구적인 흐름이 직접적으로 계산되지 않은 중규모 기상모형이나 태풍모형들을 이용하여왔다. 하지만 최근 전 세계적으로 전구 규모의 모형들이 40km 이하의 고해상도 모형들이 개발되어 20km이하의 초고해상도 시물레이션이 가능해짐에 따라 지역적인 기상현상들을 전구모형을 통해서 재현해 내고 있다. 따라서 본 연구에서는 고해상도 전구모형을 이용하여 태풍 실험을 하고자 하며, 독일기상청에서 개발된 Icosahedral-hexagonal 격자체계의 GME전구 모형을 이용한 태풍모의 결과를 기상청 태풍 best track과 비교 분석 하였다. 실험에 사용된 모형 분해능은 연직 47layer (7 soil layer 포함), 수평 약 40km와 20km으로 구성되었다. 최근 3년($2005{\sim}2007$)간의 동아시아지역을 지나간 태풍을 대상으로 하였다. 태풍모의 시작시간은 각 TD(Tropical Depression)발생 24시간 전 자료를 이용하였으며, 각 태풍의 소멸 24시간 후까지 모의하였다. GME 모형을 이용한 태풍모의 결과에서 best track의 경우 모의 시작 후 약 168시간 forcast 결과가 매우 유사한 경로를 따라 진행해 가고 있으며, 태풍의 전향이 이루어지는 시각은 ${\pm}3$시간 내외의 오차를 보이고 있다. 태풍경로의 경우 40km 결과에 비해 20km 모의 결과가 best track에 더 가까운 결과를 보이고 있다. 중심기압변화의 경우 40km의 결과가 20km 결과에 비해 변화경향이 유사한 형태를 보이고 있으며, 20km 결과의 경우 중심기압의 변화가 다소 급하게 나타나는 경향을 보이는 특성을 가지고 있지만 40km결과에 비해 최저 중심기압이 더욱 뚜렷하게 나타나고 있으며 특히, MANYI case의 경우 관측값 930hPa보다 더 낮은 911.4hPa의 결과를 보이고 있다. 풍속의 경우도 중심기압변화와 유사한 결과를 보이고 있으나, 최대 풍속의 경우 40km 결과에 비해 20km결과가 관측과의 오차범위가 $2{\sim}3\;m/s$ 내외로 나타나고 있다. 그리고 GME모형의 경우 태풍(TD) 발생 약168시간 이전에 예측이 가능한 결과를 보인다. 이 연구의 결과는 다른 기상모형에서 태풍 강도가 약하게 모의되던 현상이 상당히 개선된 것을 알 수 있으며, 이는 20km 고해상도 GME 모형이 태풍예측모형으로 활용이 간능 할 것으로 사료 된다.

• The Journal of Korean Society for Radiation Therapy
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• v.4 no.1
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• pp.71-77
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• 1990

The present study was undertaken to investigate effects of ionizing radiation on DNA synthesis and chromosomal abnormality in cultured submandibular gland(SG) cells. SG cells from C57BL/6N Crj mice were cultured in Dulbecco's modified Eagle's medium (DME) supplemented with $10\%$ fetal bovine serum, antibiotics and fungizone. The cultured SG cells were irradiated with graded doses of gamma ray ($^{60}Co$) at a dose rate of 58.4rad/min. The effect of irradiation of $^{60}Co$ on DNA synthesis in cultured cells was evaluated by measuring the incorporation of 3H-TdR. Using conventional chromosome techniques and Giemsa staining methods, chromosomal abnormalities in cultured SG cells, induced by irradiation of $^{60}Co$ werw examined. Cytological observations were carried out by a light microscope with high resolving power. The results obtained were as follows : 1. DNA synthesis of SG cells was quantitatively dependent on a radiation dose compare to control. 2. A polyploids and few chromosome-type break, such as single and double breaks, deltions and triradial figures were more predominantly in irradiated SG cells than in control. This increase of chromosomal abnormality was in the proposition to the irradiation doses.

• Analytical Science and Technology
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• v.24 no.3
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• pp.200-211
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• 2011

In this study, 13 compounds including four volatile fatty acids (VFA) and nine volatile organic compounds (VOC) were analyzed by cryogenic trapping-thermal desorption technique. In order to evaluate the analytical method for VFA, calibration experiments were performed using five different sorbent materials. When the calibration results are compared between different sorbents, sampling tube filled with Carbopack X showed the highest response factor (RF) for both VFA and VOC. To validate this new analytical method for VFA using cryogenic trapping-thermal desorption technique, this method was compared with alkali absorption method recommended by the odor prevention law of the Korea Ministry of Environment (KMOE). For this purpose, unknown samples were analyzed by two different methods, i.e., cryogenic trapping-thermal desorption (TD) and alkali absorption with solid phase microextraction (SPME). When the results of two different methods were compared, ratios of concentrations determined by the two analytical methods (TD/SPME) was found as 0.46 (valeric acid) ~ 0.71 (isovaleric acid). Therefore, additional study is required to properly establish and find stable analytical conditions for VFA analysis. Furthermore, comparison between two different methods should be made with more reliable calibration approaches.