• Proceedings of the KIEE Conference
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1360_1361
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• 2009

일반적으로 AC PDP는 Xe+Ne이 동작가스로 사용된다. 본 연구에서는 Xe 분압을 50, 60, 80, 100 Torr로 고정한 상태에서 전체 가스압력을 변화시키고 Short 방전 갭으로 $80{\mu}m$를, Long 방전 갭으로 $180{\mu}m$ 적용함으로써 나타나는 AC-PDP의 방전특성을 분석하였다. 여기에 Xe 분압을 Short 방전 갭에서는 80, 100 Torr로, Long 방전 갭에서는 50, 60, 80 Torr로 각각 고정하고, Ne 압력을 변화시킴에 따라 나타나는 방전개시전압, 소비전력, 휘도, 발광효율을 측정하여 높은 휘도와 효율을 가지면서 방전개시전압을 최대한 낮출 수 있는 적정 조합을 연구하였다. 실험결과, Short 방전 갭 패널은 소비전력이 26% 낮았고, Long 방전 갭 패널은 휘도가 45% 높았다. 휘도, 소비전력 등 여러 가지 측면을 고려하였을 때, 방전개시전압이 가장 낮은 Short 방전 갭, Xe 절대분압 80 Torr, Xe 35%(Xe+Ne=286 Torr)에서의 방전 특성이 가장 우수하였다.

• Journal of the Microelectronics and Packaging Society
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• 제27권2호
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• pp.11-17
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• 2020

In this study, Ag-functionalized SnO₂ nanowires are presented for NO₂ gas sensitive sensors at low temperatures (50℃). SnO₂ nanowires were synthesized using vapor-liquid-solid method, and Ag metal particles were functionalized on the surface of SnO₂ nanowires using flame chemical vapor deposition method. As a result of the sensing test about Ag-functionalized SnO₂ nanowires based sensor, the response (R_g/R_a) to 10 ppm NO₂ was 1.252 at 50℃. We believe that metal-functionalizing is a one of good way to increase the feasibility about semiconductor gas sensor.

• Journal of the Korean Institute of Intelligent Systems
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• 제21권1호
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• pp.49-54
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• 2011

In this paper, we represent a mobile robot which can recognize chemical odor, measure concentration, and track its source indoors. The mobile robot has the function of smell that can sort several gases in experiment such as ammonia, ethanol, and their mixture with neural network algorithm and measure each gas concentration with fuzzy rules. In addition, it can not only navigate to the desired position with vision system by avoiding obstacles but also transmit odor information and warning messages earned from its own operations to other nodes by multi-hop communication in wireless sensor network. We suggest the way of odor sorting, concentration measurement, and source tracking for a mobile robot in wireless sensor network using a hybrid algorithm with vision system and gas sensors. The experimental studies prove that the efficiency of the proposed algorithm for odor recognition, concentration measurement, and source tracking.

• Proceedings of the KIEE Conference
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.122-123
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• 2007

고전압 가스 차단기에서는 긴 스트로크 동안 가스반발력을 극복하고 빠르게 차단할 수 있는 액추에이터가 필요하다 기존에는 공압식, 유압식, 스프링 액추에이터와 같은 기계적인 장치가 사용되었다. 그러나 기존 액추에이터에서는 소음, 에너지 손실, 고가적의 단점이 있어, 근래에 들어 PMA, 모터와 같은 전기적 장치도 사용되고 있다. 전기 액추에이터는 간단한 구조로 되어 있어 기계적 손실을 줄일 수 있고 소음이 적은 장점이 있다. 전자석 조작기의 연구 필요성에 따라 새로운 형태의 전자석 조작기 Electro Magnetic Force driving Actuator(EMFA)가 개발되어 고전압 가스 차단기에 적합하다고 분석되었다. EMFA의 동특성을 얻기 위한 과도상태 해석에서는 2차원 유한요소법을 이용하여 얻은 전자기적 해석을 회로, 운동방정식과 연계하여 시간차분법을 사용하여 해석하였다. 하지만 2차원과 3차원의 전자기 해석은 차이를 보인다는 것을 확인하였고 정확한 전자기 해석을 위해 3차원 동특성 해석을 수행하여 실험결과와 비교하였다.

• The Transactions of the Korean Institute of Electrical Engineers B
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• 제49권6호
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• pp.387-394
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• 2000

This paper presents a method of cold gas flow-field analysis within puffer type GCB(Gas Circuit Breaker). Using this method, the entire interruption process including opening operation of GCB can be simulated successfully. In particular, the distortion problem of the grid due to the movement of moving parts can be dealt with by the fixed grid technique. The gas parameters such as temperature, pressure, density, velocity through the entire interruption process can be calculated and visualized. It was confirmed that the time variation of pressure which was calculated from the application of the method to a model GCB agreed with the experimental one. Therefore it is possible to evaluate the small current interruption capability analytically and to design the interrupter which has excellent interruption capability using the proposed method. It is expected that the proposed method can reduce the time and cost for development of GCB very much. It also will be possible to develop the hot-gas flow-field analysis program by combining the cold-gas flow field program with the arc model and to evaluate the large current interruption capability.

• Journal of IKEEE
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• 제23권4호
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• pp.1400-1407
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• 2019

In this paper, we propose a support vector machine (SVM) based gas classifier that can support real-time self-learning. The modified sequential minimal optimization (MSMO) algorithm is employed to train the proposed SVM. By using a shared structure for learning and classification, the proposed SVM reduced the hardware area by 35% compared to the existing architecture. Our system was implemented with 3,337 CLB (configurable logic block) LUTs (look-up table) with Xilinx Zynq UltraScale+ FPGA (field programmable gate array) and verified that it can operate at the clock frequency of 108MHz.

• Journal of IKEEE
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• 제22권3호
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• pp.700-705
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• 2018

In this paper, we propose the gas classifier based on restricted column energy neural network (RCE-NN) and present its hardware implementation results for real-time learning and classification. Since RCE-NN has a flexible network architecture with real-time learning process, it is suitable for gas classification applications. The proposed gas classifier showed 99.2% classification accuracy for the UCI gas dataset and was implemented with 26,702 logic elements with Intel-Altera cyclone IV FPGA. In addition, it was verified with FPGA test system at an operating frequency of 63MHz.

• Journal of Sensor Science and Technology
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• 제6권4호
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• pp.274-279
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• 1997

NOx sensors using tungsten oxide films as a base material were prepared and their electrical and sensing characteristics have been investigated. The $WO_{3}$ thick films doped with $SnO_{2}$ or $TiO_{2}$ showed higher sensitivity and better sorption characteristics to NOx gas than the pure $WO_{3}$ films material in air at operating temperature of $400^{\circ}C$. By addition of noble catalysts, such as Ru or Au, to the $TiO_{2}-WO_{3}$ thick films, their sensitivity, recovery and selectivity to NOx gas were found to be more enhanced.

• Journal of the Korean Institute of Gas
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• 제6권1호
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• pp.52-58
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• 2002

The PIG(Pipeline Inspection Gauge) is inserted in the pipeline and stores data of pipeline. In order to investigate the status of pipeline, a lot of sensors such as caliper, pressure, IMU and odometer are used. In this paper, the navigation storage data system for PIG is developed. It has master/slave structure for a real time operation. The master system stores data, while the slave system acquire the data from sensors. The performance of the developed system is verified by pull rig test.

• Journal of the Korean Society of Propulsion Engineers
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• 제23권3호
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• pp.9-17
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• 2019

Variable guide vanes(VGVs) that consist of link mechanisms and an actuator system are required for an aircraft gas turbine engine to adjust the incidence angle of stator vanes. In this study, we developed a VGV actuator system for three-stage VGVs with two hydraulic actuators. The requirements for the actuator system were derived by analyzing the link mechanisms and air loads, and a hydraulic power-pack was developed based on these requirements. Through a load test using the actuator test-rig and the application of synchronizing control logic with proper control gains, the actuator system could be developed and verified.