• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.65-66
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• 2010

This paper deals with PMSM control method for electric scooter. Electric scooter's motor has special structure that is hard to attach resolver or encoder. This paper suggests a method that it is performed of vector control for PMSM using hall sensor. After driving BLDC motor in low speed typically, driving mode is changed to PMSM operation and performs MTPA and flux weakness control. Proposed method is verified through simulation and testing.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.746-751
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• 2002

This purpose of this study was to design the effect of recovering of a hand amputees by myoelectronic hand. It was designed with 2 degree of freedom in tile laboratory. Myoelectronic hand had only one degree of freedom and one movement until now. Also this myoelectronic hand had multi-joint system. Myoelectronic hand data was obtained by measuring hand and data was applied when it was designed myoelectronic hand. PID controll of myoelectronic hand was used to it. Displacement control was applied the first link of finger. Experiment was accomlkished in Tip grasp, power grasp and Hook grasp modes. Displacement controll was good in low frequency. Velocity control was applied to each mode. This myoelectronic hand with a hand amputees could do some jobs such as grasping materials. Further studies were needed to evaluate the effect of a myoelectronic hand with more precise laboratory equipment.

• 환경위생공학
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• 제13권3호
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• pp.72-78
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• 1998

For investigation into gas permeation characteristics, the porous alumina membrane with asymmetrical structure, having upper layer with 10 nanometer under of pore diameter and lower layer with 36 nanometer of pore diameter, was prepared by anodic oxidation using DC power supply of constant current mode in an aqueous solution of sulfuric acid. The aluminium plate was pre-treated with thermal oxidation, chemical polishing and electrochemical polishing before anodic oxidation. Because the pore size depended upon the electrolyte, electrolyte concentration, temperature, current density, and so on, the the membranes were prepared by controling the current density, as a very low current density for upper layer of membrane and a high current density for lower layer of membrane. By control of current quantity, the thicknesses of upper layer of membranes were about $6{\;}{\mu}m$ and the total thicknesses of membranes were about $80-90{\;}{\mu}m$. We found that the mechanism of gas permeation depended on model of the Knudsen flow for the membrane prepared at each condition.

• 열처리공학회지
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• 제6권4호
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• pp.243-248
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• 1993

A Circulating Fluidized-Bed (CFB) with an internal nozzle and a partition wall was proposed. The technique of fluidization is related to operations first used commercially in the fields of metallurgical and mechanical engineering such as the heat treatment of metals and power station combustors. In the modified CFB, an internal nozzle and a partition wall were additionally set in the main bed. This cold mode CFB apparatus made of acrylic resin; the main bed is 1,500mm high and 100mm in the inner diameter, the internal nozzle is 130mm high and 10mm in the inner diameter, and the partition wall is 7mm thick and 100mm in the diameter. Glass beads of $89{\mu}m$ in the mean diameter were employed as bed materials.

• International Journal of Automotive Technology
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• 제7권6호
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• pp.659-666
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• 2006

EGR(Exhaust Gas Recirculation) systems are extensively used to reduce NOx emissions in light duty diesel engine but its application to heavy duty diesel engines is yet to be widely implemented. In this study, the simulation model for a EURO 3 engine was developed using WAVE and then its performance and emission levels were verified with experimental results. The possibility of operating a EURO 3 engine with LPL EGR system to satisfy the EURO 4 regulation was investigated. Each component of the engine was modeled using CATIA and WaveMesher. The engine test mode was ESC 13, and the injection timing and fuel quantity were changed to compensate for the reduction of engine power caused by applying EGR. As a result of the simulation, it was found that EURO 4 NOx regulation could be satisfied by applying an LPL EGR system to the current EURO 3 engine.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2016년도 춘계학술발표대회
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• pp.412-413
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• 2016

최근 그린IT가 주요 사업으로 급부상하면서 다양한 분야에서 소비전력 저감 관련 연구가 활발히 진행 중이다. 특히, 멀티미디어서비스 발전에 따라 '국내 셋톱박스가 2,000만대 이상 보급되었으나 미사용 대기시간에도 상당한 양의 전력을 소비하여 국가 전력 수급에 많은 영향을 주고 있어 이에 대한 해결방안이 시급히 요구되고 있는 상황이다. 방송 서비스 사업자는 방송 콘텐츠의 활용성 증대, H/W교체 주기 연장 및 소비전력 저감 등의 이점으로 인하여 저전력 모드를 지원하는 셋톱박스에 가상화 서비스 제공 기술을 적용하기 위한 방법을 또한 모색하고 있다. 본 논문은 셋톱박스의 발전 방향이 하이브리드화, 고기능/복합화 함으로써 소비전력이 더욱 증가하고 있으므로 셋톱박스의 소비전력 저감을 보장하고, 가상화 서비스를 제공하기 위한 고려사항과 에너지 효율성을 보장하는 방법을 제공한다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.694-697
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• 2007

In this paper, a nonlinear finite element analysis program NUCAS, which has been developed for assessment of pressure capacity and failure mode for nuclear containment building is described. Degenerated shell element with assumed strain method and low-order solid element with enhanced assumed strain method is adapted to microscopic material and elasto-plastic material model, respectively. Finally, the performance of the developed program is tested and demonstrated with several examples. From the numerical tests, the present results show a good agreement with experimental data or other numerical results.

• 전기학회논문지
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• 제65권3호
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• pp.452-456
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• 2016

In this paper, a dual-channel readout amplifier array is realized in a standard $0.18{\mu}m$ CMOS technology for the applications of panoramic scan LADAR systems. Each channel consists of a PIN photodiode with 0.9 A/W responsivity and a 1.0 Gb/s readout amplifier(ROA). The proposed ROA shares the basic configuration of the previously reported feedforward TIA, except that it exploits a replica input to exclude a low pass filter(LPF), thus reducing chip area and improving integration level, and to efficiently reject common-mode noises. Measured results demonstrate that each channel achieves $70dB{\Omega}$ transimpedance gain, 829 MHz bandwidth, -22 dBm sensitivity for $10^{-9}BER$, -34 dB crosstalk between adjacent channels, and 45 mW power dissipation from a single 1.8 V supply.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2946-2951
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• 2008

Combustion instability is a major issue in design of gas turbine combustors for efficient operation with low emissions. Combustion instability is induced by the interaction of the unsteady heat release of the combustion process and the change in the acoustic pressure in the combustion chamber. In an effort to develop a technique to predict self-excited combustion instability of gas turbine combustors, a new stability analysis method based on the transfer matrix method is developed. The method views the combustion system as a one-dimensional acoustic system with a side branch and describes the heat source as the input to the system. This approach makes it possible to use the advantages of not only the transfer matrix method but also well-established classic control theories. The approach is applied to a simple gas turbine combustion system to demonstrate the validity and effectiveness of the approach.

• 한국광학회지
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• 제10권3호
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• pp.221-225
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• 1999

레이저선속의 퍼짐각을 개선하기 위하여 공진기 내부에 선속분할기를 갖는 양영역 공초점 불안정공진기 구리증기레이저를 구성하였다. 기하광학적 배율 M=30인 공진기에서 0.15 mard의 최소 퍼짐각을 얻었고, M=60인 공진기를 사용하여 0.1 mard 의 값을 얻을 수 있었다. 퍼짐각 개선과 관련하여 상대적인 원거리 출력밀도가 최대 130배 증가된 레이저 출력을 얻을 수 있었으며, 자체잠김현상을 보이는 펄스 형태의 레이저 발진이 관측되었다.