• 한국멀티미디어학회논문지
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• 제10권11호
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• pp.1460-1471
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• 2007

휴대용 임베디드 기기에서의 삼차원 엔진은 크게 바이트 코드를 실시간으로 해석하며 실행하는 자바 기반의 JSR184와 C언어 기반의 OpenGL/ES가 있다. 이들 두 표준에서 자바 객체를 지원하는 JSR184는 OpenGL/ES에 비하여 상대적으로 많은 프로세서의 자원을 사용하여 제한된 연산능력을 보유하고 있는 임베디드 기기에 적용할 경우 제약이 따를 수 밖에 없다. 반면에 기존 개인용 컴퓨팅 환경에서 사용되는 삼차원 컨텐츠는 자바의 장점을 이용하여 제작되었기 때문에 유럽에서 많은 사용자 층을 확보하고 있고, 또한 그 컨텐츠의 품질이 우수하여 상용 통신망인 GSM 망에서 많이 서비스 되고 있다. 따라서 GSM 망에서 사용되는 휴대용 임베디드 기기에 기존의 자바 기반 삼차원 컨텐츠를 별도의 변환 과정 없이 지원할 수 있는 JSR184의 지원이 필요하지만, 현재 개발되어 사용되는 자바 기반 삼차원 엔진은 휴대용 기기가 보유한 연산능력에 비하여 상대적으로 많은 연산량을 필요로 하기 때문에 상용제품에 적용하기에 많은 어려움이 따른다. 본 논문에서는 휴대용 임베디드 기기가 가지고 있는 충분하지 않은 연산능력을 바탕으로 자바 객체의 장점을 수용하면서 삼차원 컨텐츠의 처리속도를 향상 시킬 수 있는 바인딩 기법을 제안하였다. 제안된 바인딩 기법은 자바를 이용한 삼차원 컨텐츠를 지원하기 위하여, JSR184의 표준 인터페이스를 상위 계층에서 지원하고, OpenGL/ES와 JSR184를 서로 연결하기 위하여 이기종 코드 변환 언어인 KNI(Kilo Native Interface)를 중간 계층에서 사용하였고, 하위 계층에서 OpenGL/ES의 표준을 구현하였다. 제안하는 바인딩 기법은 모의실험을 통하여 기능을 검증하였고, ARM을 장착한 FPGA를 사용하여 그 성능을 평가하였다.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.505-512
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• 2014

A new donor-accepter-donor-accepter-donor (D-A-D-A-D) type 2,1,3-benzothiadiazole-thiophene-based acceptor unit 2,5-di(4-(5-bromo-4-octylthiophen-2-yl)-2,1,3-benzothiadiazol-7-yl)thiophene ($DTBTTBr_2$) was synthesized. Copolymerized with fluorene and indeno[1,2-b]fluorene electron-rich moieties, two alternating narrow band gap (NBG) copolymers PF-DTBTT and PIF-DTBTT were prepared. And two copolymers exhibit broad and strong absorption in the range of 300-700 nm with optical band gap of about 1.75 eV. The highest occupied molecular orbital (HOMO) energy levels vary between -5.43 and -5.52 eV and the lowest unoccupied molecular orbital (LUMO) energy levels range from -3.64 to -3.77 eV. Potential applications of the copolymers as electron donor material and $PC_{71}BM$ ([6,6]-phenyl-$C_{71}$ butyric acid methyl ester) as electron acceptors were investigated for photovoltaic solar cells (PSCs). Photovoltaic performances based on the blend of PF-DTBTT/$PC_{71}BM$ (w:w; 1:2) and PIF-DTBTT/$PC_{71}BM$ (w:w; 1:2) with devices configuration as ITO/PEDOT: PSS/blend/Ca/Al, show an incident photon-to-current conversion efficiency (IPCE) of 2.34% and 2.56% with the open circuit voltage ($V_{oc}$) of 0.87 V and 0.90 V, short circuit current density ($J_{sc}$) of $6.02mA/cm^2$ and $6.12mA/cm^2$ under an AM1.5 simulator ($100mA/cm^2$). The photocurrent responses exhibit the onset wavelength extending up to 720 nm. These results indicate that the resulted narrow band gap copolymers are viable electron donor materials for polymer solar cells.

• 한국재난정보학회 논문집
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• 제20권3호
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• pp.672-681
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• 2024

연구목적: 본 연구는 구체적인 화재 확산 모델을 확보하기 위해 NIST UL 기준 적용 시나리오와 성능위주설계 적용 시나리오를 비교 분석하고 화재 확산 모델과 표면 화재 모델의 차이점을 보고자 한다. 연구방법: FDS를 활용하여 시나리오 별로 온도·가시도·CO 센서를 설치하고 그 변화를 통해 두 시나리오를 비교 분석하였다. 연구결과: 시나리오 별로 온도·가시도·CO를 분석한 결과 NIST UL 기준 적용 시나리오는 실화재와 매우 유사하고, 성능위주설계 적용 시나리오는 가혹한 화재 상황을 보여준다. 결론: 물류창고와 같은 대형 건축물의 화재 안전 설계 시에는 실화재 및 가혹한 화재 상황을 모두 고려하여 종합적인 화재 안전 대책을 마련하는 것이 중요하다.

• 한국ITS학회 논문지
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• 제19권6호
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• pp.235-249
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• 2020

국토교통부는 2019년 12월에 세계 최초로 레벨 3 자율주행 차량에 대한 안전기준을 제정하였으며, 제어권전환을 포함한 부분 자율주행시스템의 안전과 관련된 기준들을 명시하였다. 하지만, 제정된 "부분 자율주행시스템의 안전기준"에서는 구체적인 운전 환경 등이 명시되어 있지 않다. 따라서, 자율주행자동차의 안전한 주행을 위해서는 실제로 자율주행자동차가 주행하게 될 다양한 운전 환경이 제어권전환에 미치는 영향을 분석할 필요가 있다. 본 연구에서는 주행 시뮬레이터를 이용하여 교통상황(서비스수준 D, E, F)과 기하구조(직선 및 곡선부) 및 기상 상황(주야 및 강우)이 제어권전환 시간과 안정화시간에 어떠한 영향을 미치는 지 알아보았다. 실험 절차는 사전교육, 연습주행, 시험주행의 순서로 진행되었으며 시험주행은 교통량 및 기하구조 실험과 기상 상황 실험으로 나누어서 진행되었다. 실험 결과, 교통상황과 기상 상황은 제어권전환 시간 및 제어권전환 안정화시간에 통계적으로 유의한 영향을 미치지 않았으며, 곡선반경만이 제어권전환 안정화시간에 통계적으로 유의한 영향을 미치는 것으로 분석되었다.

• Architectural research
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• 제15권3호
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• pp.151-158
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• 2013

Offshore oil and gas process plants are exposed to hazardous accidents such as explosion and fire, so that the structural components should resist such accidental loads. Given the possibilities of thousands of different scenarios for the occurrence of an accidental hazard, the best way to predict a reasonable size of a specific accidental load would be the employment of a probabilistic approach. Having the fact that a specific procedure for probabilistic accidental hazard analysis has not yet been established especially for explosion and fire hazards, it is widely accepted that engineers usually take simple and conservative figures in assuming uncertainties inherent in the procedure, resulting either in underestimation or more likely in overestimation in the topside structural design for offshore plants. The variation in the results of a probabilistic approach is determined by the assumptions accepted in the procedures of explosion probability computation, explosion analysis, and structural analysis. A design overpressure load for a sample offshore plant is determined according to the proposed probabilistic approach in this study. CFD analysis results using a Flame Acceleration Simulator, FLACS_v9.1, are utilized to create an overpressure hazard curve. Moreover, the negative impulse and frequency contents of a blast wave are considerably influencing structural responses, but those are completely ignored in a widely used triangular form of blast wave. An idealistic blast wave profile deploying both negative and positive pulses is proposed in this study. A topside process module and piperack with blast wall are 3D FE modeled for structural analysis using LS-DYNA. Three different types of blast wave profiles are applied, two of typical triangular forms having different impulse and the proposed load profile. In conclusion, it is found that a typical triangular blast load leads to overestimation in structural design.

• JSTS:Journal of Semiconductor Technology and Science
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• 제12권4호
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• pp.458-466
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• 2012

A Dual metal gate stack cylindrical/ surrounded gate MOSFET (DMGSA CGT/SGT MOSFET) has been proposed and an analytical model has been developed to examine the impact of this structure in suppressing short channel effects and in enhancing the device performance. It is demonstrated that incorporation of gate stack along with dual metal gate architecture results in improvement in short channel immunity. It is also examined that for DMGSA CGT/SGT the minimum surface potential in the channel reduces, resulting increase in electron velocity and thereby improving the carrier transport efficiency. Furthermore, the device has been analyzed at different bias point for both single material gate stack architecture (SMGSA) and dual material gate stack architecture (DMGSA) and found that DMGSA has superior characteristics as compared to SMGSA devices. The analytical results obtained from the proposed model agree well with the simulated results obtained from 3D ATLAS Device simulator.

• 한국운동역학회지
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• 제23권1호
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• pp.77-83
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• 2013

The purpose of this study was to compare kinematic variables and stiffnesses of ankle joints between normal person and transfemoral amputee gait in order to develop or fit prosthetic leg. Twenty subjects (ten normal persons and ten transfemoral amputees) participated in this experiment, and walked three trials at a self-selected pace. The gait motions were captured with Vicon system and variables were calculated with Visual-3D. The velocity, stride length, stride width, cycle time, double limb support time and right swing time of gaits were statistically significant. Because coefficients of variability of normal persons on velocity, double limb support time and swing time were greater than transfemoral amputees, normal persons controlled these gait variables effectively. The stiffnesses of ankle joints were not statistically significant, but patterns of stiffnesses of ankle joints during three rockers were absolutely different. The negative correlations between stiffnesses of ankle joints and cycle time and swing time were presented. These differences suggest that developing and fitting prosthetic leg were demanded. Further studies should develop fitting program and simulator of prosthetic leg.

• Corrosion Science and Technology
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• 제9권6호
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• pp.247-253
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• 2010

The characteristics of selective oxidation prior to hot-dip galvanizing with the annealing atmosphere dew point and chemical composition in dual-phase steels and their effect on the inhibition layer formation relevant to coating adhesion have been studied using a combination of electron microscopic and surface analytical techniques. The annealed and also galvanized samples of 3 kinds of Si/Mn ratios with varied amounts of Si addition were prepared by galvanizing simulator. The dew point was controlled at soaking temperature $800^{\circ}C$ in 15%$H_2$ -85%$N_2$ atmosphere. It was shown that good adhesion factors were mainly uniformity of oxide particle distribution of low number density and low Si/Mn ratio prior to hot-dip galvanizing. Their effect was the greatly reduced coating bare spots and the formation of uniform inhibition layer leading to good adhesion of Zn overlay. The mechanism of good adhesion is suggested by two processes: the formation of inhibition layer on the oxide free surface uncovered with no $SiO_2$-containing particles in particular, and the inhibition layer bridging of oxide particles. The growth of inhibition layer was enhanced markedly by the delayed reaction of Fe and Al with the increase of Si/Mn ratio.

• 한국지능시스템학회논문지
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• 제22권3호
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• pp.361-366
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• 2012

본 논문은 퍼지 제어기를 이용하여 전기 이륜차의 속도를 제어한다. 전기 이륜차는 스로틀에 대하여 빠른 응답성과, 정속주행 시 안정성이 요구 된다. 그러나 현재 양산중인 전기 이륜차는 1.5KW(50cc)급으로 탑승자 및 수화물 중량, 도로 상태(비포장 길, 아스팔트 길) 및 바람의 저항 등 부하 변동에 따라 속도 변화가 매우 크므로 정속 주행이 어려우며, 오르막길과 내리막길의 경사도에 따라 급격한 속도 변화가 발생된다. 이러한 문제점을 해결하기 위하여 속도의 오차와 오차의 변화량을 퍼지 제어기의 입력 값으로 사용하고, 모터의 Q축 제어 량을 퍼지 제어기의 출력 값으로 설정 하여 퍼지 제어기를 구성하였다. 모터의 D축 제어 량은 Q축 제어 량에 비례적으로 설정하여 매입형 영구 자석 동기 전동기(Interior Permanent Magnet synchronous Motor, IPMSM)를 장착한 전기 이륜차를 구동하였다. 본 논문에 적용된 제어 대상은 1.5KW급 전기이륜차로서 모터의 속도 제어를 위하여 제안된 알고리즘을 이용한 퍼지 제어기를 사용 하였으며, 매입형 영구 자석 동기전동기의 토크 제어를 위하여 D, Q축 전류 제어기를 사용 하였다. 제안된 알고리즘을 이용한 퍼지 제어기는 설정된 속도를 잘 추종하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.80-81
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• 2012

Recently, one of the critical issues in the etching processes of the nanoscale devices is to achieve ultra-high aspect ratio contact (UHARC) profile without anomalous behaviors such as sidewall bowing, and twisting profile. To achieve this goal, the fluorocarbon plasmas with major advantage of the sidewall passivation have been used commonly with numerous additives to obtain the ideal etch profiles. However, they still suffer from formidable challenges such as tight limits of sidewall bowing and controlling the randomly distorted features in nanoscale etching profile. Furthermore, the absence of the available plasma simulation tools has made it difficult to develop revolutionary technologies to overcome these process limitations, including novel plasma chemistries, and plasma sources. As an effort to address these issues, we performed a fluorocarbon surface kinetic modeling based on the experimental plasma diagnostic data for silicon dioxide etching process under inductively coupled C4F6/Ar/O2 plasmas. For this work, the SiO2 etch rates were investigated with bulk plasma diagnostics tools such as Langmuir probe, cutoff probe and Quadruple Mass Spectrometer (QMS). The surface chemistries of the etched samples were measured by X-ray Photoelectron Spectrometer. To measure plasma parameters, the self-cleaned RF Langmuir probe was used for polymer deposition environment on the probe tip and double-checked by the cutoff probe which was known to be a precise plasma diagnostic tool for the electron density measurement. In addition, neutral and ion fluxes from bulk plasma were monitored with appearance methods using QMS signal. Based on these experimental data, we proposed a phenomenological, and realistic two-layer surface reaction model of SiO2 etch process under the overlying polymer passivation layer, considering material balance of deposition and etching through steady-state fluorocarbon layer. The predicted surface reaction modeling results showed good agreement with the experimental data. With the above studies of plasma surface reaction, we have developed a 3D topography simulator using the multi-layer level set algorithm and new memory saving technique, which is suitable in 3D UHARC etch simulation. Ballistic transports of neutral and ion species inside feature profile was considered by deterministic and Monte Carlo methods, respectively. In case of ultra-high aspect ratio contact hole etching, it is already well-known that the huge computational burden is required for realistic consideration of these ballistic transports. To address this issue, the related computational codes were efficiently parallelized for GPU (Graphic Processing Unit) computing, so that the total computation time could be improved more than few hundred times compared to the serial version. Finally, the 3D topography simulator was integrated with ballistic transport module and etch reaction model. Realistic etch-profile simulations with consideration of the sidewall polymer passivation layer were demonstrated.