• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.117-117
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• 2009

최근 고집적화 구조는 저항(resistance)과 정전용량 (capacitance)에 의한 신호 지연 (RC delay) 증가로 인한 혼선 (cross-talk noise)과 전력소모 (power dissipation)등의 문제를 발생시킨다. 칩 성능에 영향을 미치는 제한인자를 최소화하기 위해서는 저저항 배선 금속과 저유전상수 (low-k)의 층간 절연막 (IMD, intermetal dielectric) 물질이 필요하다. 최근 PECVD (plasma enhanced chemical vapor deposition)를 이용하여 증착시킨 유기살리케이트 (OSG, organosilicate glass)는 가장 유망한 저유전상수 물질로 각광받고 있다. 본 연구에서는 제일원리 연구를 통하여 OSG의 전구체 중에 하나인 DEMS 문자를 모델링하고, 에너지적으로 가장 안정한 구조를 찾아서 각 원자 간의 결합에 따른 해리에너지 (dissociation energy)를 계산하고, DEMS가 H-terminated Si 표면과 반응하는 기구에 대해 고찰하였다. 최적화된 DEMS 분자의 구조를 찾았고 DEMS 분자가 결합이 깨져 조각 분자군으로 될 때의 에너지들을 계산하였다. 계산된 해리에너지로부터 DEMS 분자의 O 원자와 C분자의 결합이 깨져서 $C_2H_5$를 조각 분자군으로 생성할 확률이 총 8가지의 경우에서 가장 높다는 것을 알 수 있었다. 8 가지의 해리된 DEMS 조각 분자군들이 H-terminated Si 표면과 반응할 때의 반응에너지를 계산한 결과 표면의 Si 원자와 DEMS 분자에서 $C_2H_5$가 해리되어 생성된 조각 분자군의 O 원자가 결합을 하고 부산물로 $C_2H_6$를 생성하는 반응이 가장 선호된다는 것을 알 수 있었다. DEMS 분자로 증착시킨 OSG에 대하여 제일원리법을 이용하여 계산한 연구는 보고된 바 없기 때문에, DEMS 분자의 각 원자 간의 해리에너지와 Si 기판과의 반응에너지는 추후 연구개발의 중요한 기초 자료가 될 수 있다.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.14-19
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• 2021

Aim of this research was to investigate the effects of Digital Elevation Model (DEM) for sensitivity analysis with two types of DEMs: 1 to 24,000 and 1 to 250,000 DEM. Another emphasis was given to the development of methodology for processing DEMs to create ArcGIS Pro and GRASS layers. This was done while developing water quality system modeling using DEMs which were used to model hydrological processes and SWAT model. Sensitivity analysis with DEMs resulted in different runoff volumes in the model simulation. Runoff volume was higher for the 1:24,000 DEM than 1:250,000 DEM, probably due to the finer resolution and slope which increased the estimated runoff from the watershed. Certainly the DEMs were factors in precision of the simulations and it was obvious during sensitivity analysis that DEMs had significant effect on runoff volumes. We suggest, however, that additional comparative research could be conducted involving more parameters such as soil and hydrologic parameters to provide insight into the overall physical system which the SWAT model represents.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.148-148
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• 2008

Low-k dielectric materials are an alternative plan to improve the signal propagation delay, crosstalk, dynamic power consumption due to resistance and parasitic capacitance generated the decrease of device size. Now, various materials is studied for the next generation. Diethoxymethlysiliane (DEMS) precursor using this study has two ethoxy groups along with one methyl group attached to the silicon atoms. SiCOH thin films were deposited on p-type Si(100) substrate by Plasma Enhanced Chemical Vapor Deposition (PECVD) using DEMS. In this study, we studied the effect of oxygen($O_2$) flow rate for DEMS to characteristics of thin films. The characteristics of thin films deposited using DEMS and $O_2$ evaluated through refractive index, dielectric constant(k), surface roughness, I-V(MIM:Al / SiCOH / Ag), C-V(MIM), deposition rate.

• Journal of the Korean Ceramic Society
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• v.46 no.4
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• pp.425-428
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• 2009

We performed a density functional theory study to investigate the interaction of DEMS (diethoxymethylsilane) with the H-terminated Si (001) surface. The optimum structure of DEMS was first calculated by a first principles study. The dissociation probability of the O-C bond of DEMS was higher than the other seven bonds based on the bond energy calculation. When the fragmented DEMS groups reacted with the H-terminated Si (001) surface, it was the most favorable among the eight reactions to form a bond between the Si atom on the surface and the O atom of a fragmented DEMS group (($C_2H_5O$)Si($CH_3$)(H)-O-) by forming a $C_2H_6$ as by-product.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.5 s.23
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• pp.53-65
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• 2002

The most widespread techniques for DEM generation are stereoscopy for optical sensor images and SAR interferometry(InSAR) for SAR images. These techniques suffer from certain sensor and processing limitations, which can be overcome by the synergetic use of both sensors and DEMs respectively. This study is associated with improvements of accuracy with consistency of image's characteristics between two different DEMs coming from stereoscopy for the optical images and interferometry for SAR images. The MWD(Multiresolution Wavelet Decomposition) and HPF(High-Pass Filtering), which take advantage of the complementary properties of SAR and stereo optical DEMs, will be applied for the fusion process. DEM fusion is tested with two sets of SPOT and ERS-l/-2 satellite imagery and for the analysis of results, DEM generated from digital topographic map(1 to 5000) is used. As a result of an integration of DEMs, it can more clearly portray topographic slopes and tilts when applying the strengths of DEM of SAR image to DEM of an optical satellite image and in the case of HPF, the resulting DEM.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.173-178
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• 2004

This paper presents photogrammetric processing to generate digital elevation models and deals with the accuracy potential of SPOT-5 HRG supermode imagery for DEM generation. The DEMs obtained from digital topographic maps of 1/5000 scale were used as the refernce DEM data. DEMs extracted from HRG dats were compared with digital topograpic map DEMs on severed test sections. And digital surface model(DSM), refering to above the ground like buildings, was produced about the test built-up area.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.393-395
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• 2003

The changes of DEMs(Digital Elevation Models) will be detected to correct the information of DEMs and/or to get the information about themselves. This study suggests the evaluation of DEM using correlation coefficient value between the target and the reference DEMs for detect the changes.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.519-521
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• 2005

In recent years, LiDAR(Light Detection and Ranging) data has been widely used to prepare digital elevation models(DEMs) with the high spatial resolution of centi-meters. This paper investigated possible applications of LiDAR-derived DEMs in surface hydrology modeling, such as characterizing flow direction, identifying sub-basins in a watershed, and calculating variables like upstream contribution area. The results were compared to the results of the DEMs from conventional topographic maps.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.37-40
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• 2008

The purpose of this paper is to extract DEMs from Spot-3 strips using orbit modeling technique. Spot-3 stereo strip images along 420km in distance were used for experiments. The orbit modeling technique has been suggested to establish accurate geometric models for a whole strip taken on the same orbit using only a small number of GCPs on the top area of the strip. This method enables extraction of orientation parameters of the scene along the strip that is needed to generate DEMs. Consequently, we were able to extract DEMs over the areas without accurate GCPs obtained by GPS surveying per each scene. Assessment of accuracy was carried out using USGS DTED. DEMs generated from the orbit modelling technique suggested showed satisfactory performance when quantitative analysis of accuracy assessment was carried out.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.335-339
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• 2005

Digital elevation models(DEM) were generated from SPOT-5 HRG supermode imagery through photogrammetric processing. The reference DEMs were obtained from digital topographic maps of 1/5000 scaleas for analyzing the accuracy of the generated DEMs. The DEMs extracted from HRG stereo image data were compared with digital topograpic map DEMs on several test sections. And digital surface models(DSM) and 3D building model was produced.