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스퍼터링 타겟용 Cu-50In-13Ga 3원계 합금 분말의 소결 및 압연 거동
김대원,김용호,김정한,김대근,이종현,최광보,손현택,Kim, Dae-Won,Kim, Yong-Ho,Kim, Jung-Han,Kim, Dae-Guen,Lee, Jong-Hyeon,Choi, Kwang-Bo,Son, Hyeon-Taek 한국분말야금학회 2012 한국분말재료학회지 (KPMI) Vol.19 No.4
In this study, we mainly focus on the study of densification of gas-atomized Cu-50 wt.%In-13 wt.%Ga alloy powder without occurrence of crack during the forming process. Cu-50 wt.%In-13 wt.%Ga alloy powder was consolidated by sintering and rolling processes in order to obtain high density. The phase and microstructure of formed materials were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical microscopy (OM), respectively. Warm rolling using copper can result in the improvement of density. The specimen obtained with 80% of rolling reduction ratio at $140^{\circ}C$ using cooper can have the highest density of $8.039g/cm^3$.
김대원,김선욱,오수철,김성운,Kim, Dae-Won,Kim, Seon-Uk,O, Su-Cheol,Kim, Seong-Un 한국전자통신연구원 2008 전자통신동향분석 Vol.23 No.1
시스템 관리(system management)라 함은 일반적으로 분산 컴퓨터 환경에서의 전사적 시스템 관리를 말한다. 그리고 네트워크가 발전함에 따라서 그 영향력도 매우 커지게 되었고 그 범위 역시 광범위하게 되어 현재 시스템 관리 영역은 하드웨어 및 소프트웨어가 접목된 복잡한 시스템으로 변모해가고 있는 한편 또 이런 복잡함을 줄이기 위하여 각 표준 단체들이 많은 노력을 기울이고 있으며 이에 참여하는 업체들도 점점 늘어나고 있는 추세이다. 본 기고문에서는 클러스터 컴퓨팅 시스템 환경에서 시스템 관리를 위한 목적으로 사용되는 많은 소프트웨어 가운데, 하드웨어 모니터링 및 시스템의 lifecycle 관리에 관한 툴을 위주로 주요 업체들의 기술과 소프트웨어의 개발 동향에 대하여 기술하고자 한다.
김대원,박종태,김종문,김태영,Kim, Dae Won,Park, Jong Tae,Kim, Jong Moon,Kim, Tae Young 대한신경외과학회 2001 Journal of Korean neurosurgical society Vol.30 No.2
A rare case of gliosarcoma with neurofibromatosis type I is presented. The patient was a 33-year-old woman who had headache and vomiting for one week. Multiple neurofibromas over her whole body with many cafeau- lait spots were present since childhood. At admission, she had no focal neurological deficit and ophthalmologic examination revealed bilateral Lisch nodules. Brain CT and MRI revealed a heterogeneously enhancing mass in the left fronto-parietal region with marked peritumoral edema and mass effect. The tumor was removed gross totally and a gliosarcoma was diagnosed histopathologically. Post operative course was uneventful with resolution of symptom, followed by radiotherapy with 60 Gy. A brief overview is given of this rare case together with the pertinent literature.
사람 교모세포종 A172 세포에서 Cisplatin에 의한 세포고사의 유도
김대원,김태영,박종태,김종문,Kim, Dae Won,Kim, Tae Young,Park, Jong Tae,Kim, Jong Moon 대한신경외과학회 2001 Journal of Korean neurosurgical society Vol.30 No.1
This study was designed to investigate the mechanism of cell death after cisplatin treatment in human glioblastoma A172 cells. Cis-diamminedichloroplatinum(Cisplatin) demonstrated cytostatic or cytotoxic effects on A172 cells in a dosedependent manner. Cisplatin-mediated cytotoxity in A172 cells was revealed as an apoptosis characterized by high molecular weight DNA fragmentation by agarose electrophoresis as well as nuclear fragmentation by Hoechst staining. Cisplatin also resulted in the activation of caspase 3-like protease as well as poly(ADP-ribose) polymerase(PARP) cleavage. Interestingly, the anti-apoptotic Bcl2 protein was degraded and furthermore, expression of p53 protein was increased by cisplatin in a time-dependent manner. Taken together, these results suggest that anticancer drug, cisplatin induces the apoptotic death of human glioblastoma A172 cells via the activations of caspase 3-like protease, degradation of anti-apoptotic Bcl2 protein and increase in the expression of p53.
차량 운전자의 공기오염물질 잠재적 노출 및 차량용 공기청정기에 의한 제어
김대원,김문현,양원호,Kim Dae-Won,Kim Moon-Hyeon,Yang Won-Ho 한국환경보건학회 2004 한국환경보건학회지 Vol.30 No.5
Vehicle occupant exposure to air pollutants has been a subject of concern in recent years because of higher levels of air pollutants inside gasoline or diesel-using vehicle, comparing to the surrounding atmosphere. Contrary to previous studies, fuel of vehicles operated in this study was liquefied petroleum gas (LPG). This study examined the potential exposure and removal efficiency of selected volatile organic compounds (VOCs), nitrogen dioxide ($NO_2$) and respirable suspended particle (RSP) by commercial air cleaning device inside vehicle under different ventilation conditions. Vehicle concentrations inside of benzene, toluene, m,p-xylene, $NO_2$ and RSP were lower under the low ventilation condition. This was indicated that outdoor air pollutants could affect the vehicle air quality inside in case metropolitan cities such as Daegu. The urban vehicle concentrations inside of benzene, toluene, m,p-xylene, $NO_2$ and RSP with air cleaning device were higher than those without air cleaning device. This means that the use of air cleaning device equipped with activated carbon filter, which was used in this study, in the interior of vehicles could be expected to reduce the vehicle occupants exposure to air pollutants effectively. In batch type reactor of laboratory scale, removal efficiencies of air cleaning device used were $97.0\%,\;95.7\%,\;94.6\%\;and\;85.5\%$ respectively in benzene, toluene, m,p-xylene and $NO_2$.
공동주택 연도별 단열기준 강화에 따른 에너지소요량 비교 연구
김대원,정광섭,김영일,김성민,Kim, Dae-Won,Chung, Kwang-Seop,Kim, Young-Il,Kim, Sung-Min 한국에너지학회 2013 에너지공학 Vol.22 No.2
에너지사용은 우리생활과 밀접한 관계성을 유지하고 있다. 사계절이 뚜렷한 우리나라로서는 건물분야에 냉,난방이 필수품처럼 여겨지는 세대에 살고있어 에너지 사용과 유지에 새로운 트렌드를 요구하고 있다. 이에따라 정부는 신축 및 기존건축물의 에너지효율 개선을 위해서 단열기준을 지속적으로 강화하여 에너지절감을 꾀하고 있다. 공동주택의 에너지효율 분석중 가장 중요한 요소가 열관류율이며 그값은 외피면적비에 대한 창면적비에 따라 난방에너지 요구량이 큰차이를 보여주고 있다. 그러므로 지속적인 효율개선 정책과 외피면적에 대한 창면적비의 규제가 필요한 시점이라 생각한다. Energy consumption is closely related to our lives. As Korea has four seasons, heating and cooling system is considered as essential facilities for the residential buildings. Accordingly, the government has continuously strengthened the design criteria to improve energy for new and existing building to save energy. The most important factor in the energy efficiency analysis for apartment is the heat transmission coefficient, and the value is significantly different as the heating energy amount is greatly different according to the window area ratio versus facade area ratio. Therefore, it is time to conduct continuous set-up for goal to enhance efficiency and restriction on window area ratio versus facade area ratio.
다발성 낭종성 병변을 보인 급성 파종성 뇌척수염 - 증례보고 -
김대원,김태영,김종문,윤기중,Kim, Dae Won,Kim, Tae Young,Kim, Jong Moon,Yun, Ki Jung 대한신경외과학회 2001 Journal of Korean neurosurgical society Vol.30 No.5
Acute disseminated encephalomyelitis(ADEM) is an uncommon immune-mediated inflammatory demyelinating disorder that typically affects the white matter of the central nervous system. Radiologic findings of acute disseminated encephalomyelitis are not pathognomomic. The differential diagnosis is always difficult. Occasionally, the clinical features, radiological and histopathological findings of patients with acute disseminated encephalomyelitis mimic the brain tumor or other space occupying lesions. The authors report a 6-year-old girl who presented with right hemiparesis two days after nausea and vomiting. Brain MRI of the patient revealed non-enhanced multiple cystic lesions in subcortical white matter of both cerebral hemisphere with prominent edema. One of the cystic lesions was resected to differentiate with metastatic tumor or inflammatory disease such as abscess and confirmed as the acute disseminated encephalomyelitis via various immunohistochemical stains. Pertinent literature is reviewed with discussion on this uncommon ADEM associated with multiple cystic lesions.
김대원,박순호,Kim, Dae Won,Park, Soon-Ho 대한화학회 2014 대한화학회지 Vol.58 No.6
단백질 폴딩 반응에서 정전기적 상호작용의 역할을 라이신 29를 알라닌으로 치환한 변이 유비퀴틴을 사용하여 탐색하였다. 유비퀴틴의 입체구조에서 라이신 29의 곁사슬은 글루탐산 16과 아스파르산 21의 곁사슬과 근접한 거리에 있어서 곁사슬끼리 정전기적 상호작용을 통하여서 삼차원 입체구조를 안정화시킬 것으로 예측되었다. 라이신을 알라닌으로 치환하여 정전기적 상호작용을 제거하였을 때 유비퀴틴의 native state의 구조적 안정성이 ~20% 감소한 점은 라이신 29에 의한 정전기적 상호작용이 단백질 삼차구조의 안정성에 상당히 기여하고 있다는 점을 시사하였다. 폴딩 반응의 진행 과정을 stopped-flow 장치로 측정한 folding kinetics 실험은 이전에 관찰된 것과 마찬가지로 unfolded state에서 native state로 진행하는 과정에 중간단계를 거치는 three-state on-pathway 메커니즘을 따르는 것으로 나타났다. 더욱이 라이신 29에 의한 정전기적 상호작용이 중간단계의 구조적 안정성에 기여하는 정도가 native state의 구조적 안정성에 기여하는 정도의 ~55%인 것으로 나타났다. 이는 유비퀴틴 폴딩의 중간단계의 구조도 라이신 29에 의한 정전기적 상호작용에 의하여 상당히 안정화 된다는 것을 의미하며 따라서 정전기적 상호작용이 단백질 삼차원 입체구조의 골격이 완성된 폴딩의 마지막 단계에 형성되어 단백질 native state의 안정성에만 기여하는 것이 아니라 중간단계가 형성되는 폴딩 반응의 초기에도 형성되어 폴딩 반응을 이끌어가는데도 기여한다는 것을 의미한다. The contribution of electrostatic interactions to protein folding reaction was studied by using mutant ubiquitin with lysine to alanine mutation at residue position 29. Based on the three dimensional structure of ubiquitin, lysine 29 is located close to negatively charged glutamate 16 and aspartate 21 and considered to stabilize the native state of ubiquitin by electrostatic interactions between these residues. The equilibrium unfolding experiment showed that the native stability was decreased by about ~20% upon mutation. This observation indicates lysine 29 indeed forms electrostatic interactions with nearby residues. Folding kinetics measurements using stopped-flow device and quantitative analysis of kinetics data indicate that ubiquitin folds from unfolded state to native state via intermediate state as observed previously. This intermediate state was observed to form immediately after the initiation of folding reaction. The folding intermediate was shown to be destabilized considerably upon lysine to alanine mutation. These observations indicate that electrostatic interactions can form early stage of protein folding and hence lead the folding reaction.
JPEG2000 정지영상을 위한 블록 에너지 기반 적응적 이산 웨이블릿 변환
김대원,Kim, Dae-Won 한국융합신호처리학회 2007 융합신호처리학회 논문지 (JISPS) Vol.8 No.1
본 논문에서는 웨이블릿 변환에 기반을 둔 JPEG2000 정지영상의 압축 시도 시 웨이블릿 변환을 decomposition 하는 레벨과 이를 구성하는 블록의 활성도를 내포하는 에너지에 기반 하여 그 양에 따라 적응적으로 계수 변환 후 복원시 효율적 자원 관리를 통하여 복잡도를 감소시키고 계산량을 줄이는 적응식 DWT 변환 기법을 제안하였다. 수많은 멀티미디어 응용 분야 또는 서비스 중의 하나인 디지털 카메라의 핵심 분야를 차지하고 있는 정지영상 압축 분야에서의 최첨단 기술을 꼽으라면 단연 JPEG2000 표준을 이용한 압축, 전송의 응용 분야이다. JPEG2000 기반의 정지영상압축 전송 표준의 핵심을 이루고 있는 웨이블릿 변환은 기존의 JPEG 표준에 사용된 이산 코사인 변환의 약점인, 복원 시 나타나는 블록킹 문제를 해결한 대안이다. 적응식 DWT 변환을 거친 정지영상이 복원된 후 일반적인 과정의 웨이블릿 변환 후 복원된 영상간의 MSE(Mean Square Error), PSNR(Peak Signal to Noise Ratio), 0의 계수의 개수 등을 비교하여 본 연구에서 제안된 에너지 기반의 적응적 웨이블릿 변환의 우수성을 연산 속도를 계산함으로써 검증하였다. The proposed algorithm in this paper is based on the wavelet decomposition and the energy computation of composed blocks so the amount of calculation and complexity is minimized by adaptively replacing the DWT coefficients and managing the resources effectively. We are now living in the world of a lot. of multimedia applications for many digital electric appliances and mobile devices. Among so many multimedia applications, the digital image compression is very important technology for digital cameras to store and transmit digital images to other sites and JPEG2000 is one of the cutting edge technology to compress still images efficiently. The digital cm technology is mainly using the digital image compression features so that those images could be efficiently saved locally and transferred to other sites without any losses. JPEG2000 standard is applicable for processing the digital images usefully to keep, send and receive through wired and/or wireless networks. The discrete wavelet transform (DWT) is one of the main differences to the previous digital image compression standard such as JPEG, performing the DWT to the entire image rather than splitting into many blocks. Several digital images m tested with this method and restored to compare to the results of conventional DWT which shows that the proposed algorithm get the better result without any significant degradation in terms of MSE & PSNR and the number of zero coefficients when the energy based adaptive DWT is applied.
Traffic Analysis of a CAN-based Control System
김대원,Kim, Dae-Won Institute of Korean Electrical and Electronics Eng 2001 전기전자학회논문지 Vol.5 No.1
This paper deals with an architecture of network-based control system using the CAN(Controller Area Network) protocol and its traffic analysis. It is difficult to determine an optimal network-based control architecture for a specific AGV(Autonomous Guided Vehicle) system with a manipulator arm. The fixed number of periodic messages to be occurred is pre-defined in the system. To determine whether the proposed system architecture is effective or not, we perform traffic analysis for the real-time communication of all messages. Through simulations, the range of transmission speed is found satisfying required conditions and the permissible number of additional sensors is investigated for improving the system performance, when the sampling periods of analog sensors are determined under fixed condition that the transmission speed is over 500Kbps.