• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.75.1-75.1
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• 2010

This research presents a fuel cell simulator for control logic verification and operator training. Nowadays, power industries are focusing on clean energy as a response to new policy. The fuel cell can be the solution for clean energy, but operating technology is not well developed compared to other conventional power plans because of its short history. Therefore we need a simulator to verify the new control strategy and train operators, because the price of a real fuel cell system is too high and mechanically weak to be used for these kind of purposes. To develop the simulator, a 300 KW MCFC(Molten Carbonate Fuel Cell) system was modeled with stack, BOPs(pre-reformer, steam generator, etc) and mechanical components(valves, pipes, pumps, blowers, etc). The process model was integrated to emulated control system and HMI(Human Machine Interface). A static load and open loop tests were conducted for verifying the accuracy of the process model, since it is the most important part in the simulation. After verifying the process model, an automatic load change and start-up tests were conducted to verify the performance of a new control strategy(logic and functional loops).

• Journal of IKEEE
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• v.15 no.1
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• pp.23-28
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• 2011

This paper describes design and implementation of a spread spectrum clock generator(SSCG). The proposed architecture generates the spread spectrum clock controlling a input voltage signal for VCDL(Voltage Controlled Delay Line). Spread charge pump is controlled by the SSC modulation logic block provides a control signal to VCDL through LPF in DLL. By using this architecture, chip area and power consumption can be reduced because it is not necessary additional circuit to control modulation rate. This circuit has been designed and fabricated using the UMC 0.25um CMOS technology. The chip occupies an area of 290${\times}$120um^2.

• 전자공학회논문지 IE
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• v.47 no.2
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• pp.1-7
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• 2010

This paper presents a low power digital PLL architecture and design for implementation of the PLL-based frequency synthesizers. In the proposed architecture, a wide band digital logic quadricorrelator is used for preliminary frequency detector and a narrow band digital logic quadricorrelator is used for final DCO control. Also, a circuit technique for reducing leakage current is adopted in order to minimize the standby mode power consumption of the deactivated block. The proposed digital PLL is designed and verified by MyCAD with MOSIS 1.8V $0.35{\mu}m$ CMOS technology, and the simulation results show that the power consumption can be lowered by more than 20%.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.6
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• pp.39-51
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• 1996

In the turning maneuver of the vehicle, its motion is mainly dependent on the genuine steering characteristics in view of the directional stability for stable turning ability. The under steer vehicle has an ability to maintain its own directonal performance for unknown external disturbances to some extent. From a few years ago, in order to acquire the more enhanced handling performance, some types of four wheel steering vehicle were considered and constructed. And, various rear wheel control logics for external disturbances has not been suggested. For this reason, in this posed rear wheel control logic is based on the yaw rate feed back type and is slightly modified by an yaw rate tuning factor for more stable turning performance. And an external disturbance is defined as a motivation of the additional yaw rate in the center of gravity by an uncertain input. In this study, an external disturbance is applied to the vehicle as a form of the additional yawing moment. Finally, the proposed rear wheel control logic is tested on the multi-body analysis software(ADAMS). J-turn and double lane change test are performed for the validation of the control logic.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.1
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• pp.53-62
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• 2023

Due to the recent increase in new and renewable energy, gas turbine generators start and stop every day to supply high-quality power, and accordingly, the life span of high-temperature parts is shortened and the failure of combustion chamber temperature sensors increases. Therefore, in this study, we proposed a fuzzy logic-based failure diagnosis algorithm that can accurately diagnose and systematically detect the failure of the sensor when the dual temperature sensor used for gas turbine control fails, and to confirm the usefulness of the proposed algorithm We tried to confirm the usefulness of the proposed algorithm by performing various simulations under the matlab/simulink environment.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.7 s.361
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• pp.24-30
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• 2007

Latching optical switches and optical logic gates with AND or OR, and the INVERT functionality are demonstrated, for the first time, by the monolithic integration of a differential typed vertical cavity laser with depleted optical thyristor (VCL-DOT) structure with a low threshold current of 0.65 mA, a high slope efficiency of 0.38 mW/mA, and high sensitivity to input optical light. Many kinds of logic functions (AND, OR, NAND, NOR, and INVERT) are experimentally demonstrated using a differential switching operation scheme changing the intensity of a reference input beam without any changes of electrical circuits.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1668_1669
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• 2009

보일러 연료제어의 근본 목적은 보일러 입력에너지와 출력에너지 간의 평형을 유지하는 것이다. 보일러 출력에너지는 유출증기가 가지고 나가는 총 에너지에 해당하고, 입력에너지는 보일러에 공급되는 연료의 연소에 의해 발생하는 열 에너지에 해당한다. 보일러 연료의 공급과 연소제어에는 여러 가지 변수가 상존하고 있으며, 이 변수들의 영향을 잘 반영하여 필요한 연료량을 실시간으로 정확히 제어하는 것이 결코 쉬운과제가 아니다. 석탄연소발전소의 주연료는 당연히 석탄이며 석탄을 입자가 매우 적은 미분탄으로 가공해서 연소하는 '미분탄 연소방식'을 많이 사용한다. 석탄의 공급과 연소에 영향을 미치는 인자로는 도입 탄종 변화에 따른 발열량, 수분함유량, 기타 성분의 변화가 있으며, 미분기 특성 및 성능변화, 연소용 공기 공급상태 변동에 따른 연소상태변화 등을 들 수 있다. 이 논문에서는 국내 석탄화력 발전소에서 가장 많이 사용하고 있는 전형적인 보일러 연료제어 전략과 알고리듬을 분석하였으며, 여기서 습득한 이론을 바탕으로 내년에는 실제 발전소에 적용할 연료제어로직을 설계할 예정이다.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.6
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• pp.915-925
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• 2012

On-off control performance of target pumping station was experimented by changing measurement methods for storage level or inflow and operating logic for control system setting. Four scenarios with different measurement methods and operational logic were examined in the Matlab/Simulink environment. Controller's on-off control repetition that was frequent before has been reduced and more effective and stable system operation was found to be possible with the scenarios. Moreover, defensive operation enforced prevention of floods by changing measurement methods enabled economic operation that made an utmost use of storage volumes.

• Journal of Power System Engineering
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• v.5 no.2
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• pp.87-92
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• 2001

Automotive suspension system is a mechanism for isolation of the vibration coming from the road inputs. Recently, the electronically controlled suspension systems which may improve ride and handling performance have been developed. Here, the continuously controlled semi-active suspension system is focused. As a mechanism to control damping forces continuously, a solenoid valve is used. The modeling for the solenoid valve is introduced briefly, a vehicle dynamics modeling is constructed, and then combined system model is completed. To design the efficient control algorithm for the semiactive suspension system the knowledge based fuzzy logic is applied and the technique how to apply the sky-hook theory to the fuzzy logic is developed. Finally, to confirm the improvement of performance the computer simulation is carried out.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.3 s.18
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• pp.140-148
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• 2004

Fault detection and isolation(FDI) and reconfigurable flight control system provide better survivability even though actuator faults occur. In this study, a new fault detection and isolation algorithm is proposed using fuzzy logic. When the FDI system detects the actuator fault, the fuzzy logic investigates the state variables to find which actuator has fault. Proposed fuzzy detection algorithm detect not only a single fault but also multiple faults. After detecting the fault, the reconfigurable flight control system begins operating for compensating the effects of the fault. A numerical simulation using six degree-of-freedom nonlinear aircraft model is performed to verity the performance of the proposed fault detection and isolation scheme.