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1D/3D를 연계한 중소형 트럭 엔진룸의 냉각성능에 관한 해석적 고찰
최정환(Jeonghwan Choi),김민호(Minho Kim),박종찬(Jongchan Park),임정환(Junghwan Lim) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Recently, the automakers pay attention to new diesel engine technologies such as cooled exhaust gas recirculation (EGR) and selective catalytic reduction (SCR) to meet the emission regulations. Since these additional components for EGR, SCR cause the increase of heat rejection rate in engine, it leads into a new cooling system design to meet the cooling performance. In this study, 1D and 3D simulation have been performed simultaneously to visualize the cooling air flow field in an engine compartment and to obtain the information for adjustment of the 1D network model. The feasibility of using the 1D network simulation in the initial design stage is studied to find out its validity and limitation in cooling module design, through comparison with the results of the vehicle test and the 3D CFD analysis. As a result of this study, it is found out that the 10 network model can efficiently predict reliable results at the early design stage.
적응형 복합 분류 알고리즘을 이용한 초소형 전자소자 탐지 향상 기법
김광열(Kwangyul Kim),임정환(Jeonghwan Lim),김송강(Songkang Kim),조준경(Junkyung Cho),신요안(Yoan Shin) 한국통신학회 2013 韓國通信學會論文誌 Vol.38 No.6C
본 논문은 지적재산권 보호를 위한 방안으로 적응형 알고리즘 기반의 초소형 전자소자 탐지 기법을 제안한다. 전자소자를 탐지하는 기본 원리는 분류기의 송신기에서 특정 기본 주파수의 전파가 은닉된 물체로 전파되면, 물체로부터 반사되어 수신기로 들어오는 2차 및 3차 고조파의 크기를 분류기가 비교함으로써 판별하게 된다. 하지만, 측정 과정에서 발생하는 잡음 및 전자파의 간섭으로 인해 분류의 성능이 저하되므로, 이러한 환경에서도 은닉된 전자소자를 적응적으로 판별하기 위해 Fuzzy c-Means 클러스터링 알고리즘과 k-Nearest Neighbor 분류 알고리즘을 복합적으로 이용하는 방안을 제시한다. 모의실험 결과, 제안 기법이 잡음 및 전자파 간섭 환경에서도 적응적으로 전자소자 잘 탐지할 수 있었으며, 이에 따라 지적재산권을 효율적으로 보호할 수 있을 것으로 기대된다. This paper proposes improved detection schemes for concealed micro-electronic devices using clustering and classification of radio frequency harmonics in order to protect intellectual property rights. In general, if a radio wave with a specific fundamental frequency is propagated from the transmitter of a classifier to a concealed object, the second and the third harmonics will be returned as the radio wave is reflected. Using this principle, we exploit the fuzzy c-means clustering and the k-nearest neighbor classification for detecting diverse concealed objects. Simulation results indicate that the proposed scheme can detect electronic devices and metal devices in various learning environments by efficient classification. Thus, the proposed schemes can be utilized as an effective detection method for concealed micro-electronic device to protect intellectual property rights.
최호경(Hokyung Choi),김상도(Sangdo Kim),유지호(Jiho Yoo),임정환(Jeonghwan Lim),임영준(Youngjoon Rhim),이시훈(Sihyun Lee) 한국연소학회 2010 KOSCOSYMPOSIUM논문집 Vol.- No.40
This paper describes the potential application of ash-free coal to direct carbon fuel cell (DCFC). DCFC can be made of typical fuel cell components and generates the electric energy by direct electrochemical oxidation of carbon, replacing hydrogen with solid carbon fuel. Carbon is mostly originated from coal, which is readily available, easily transportable, and economical. However, employing coal as a carbon source has been excluded, mainly due to its high ash content. The ash-free coal, produced by solvent extraction of combustibles from raw coal, can be applicable as carbon fuel to DCFC. The successful adaption may cut the fuel cost to one third of usual hydrogen fuel cells. In addition, 80% of power generation efficiency can be achieved and CO₂ emission from the conventional coal-fired power plant can be reduced by 90%.