• 제어로봇시스템학회논문지
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• 제12권12호
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• pp.1249-1255
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• 2006

This paper presents a constant power control logic for perfect starting a microtubine in vehicle. Under extremely low temperature, performance of the start-up system is severely dropped than that of room temperature because of increasing of load of mechanical parts including engine core and drop of the lead-acid battery capacity. Unfortunately, performance drop of lead-acid battery makes severe problems that cause a malfunction of fuel and lubrication system and power fail of digital devices. So we propose the new start-up logic by constant output power control of lead-acid battery using PWM inverter controller for preventing above problems and keeping good performance of start-up system for microturbine. Also, we prove usefulness of new start-up logic through experimental results under $-32^{\circ}C$ ambient temperature.

• 전자공학회논문지B
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• 제30B권2호
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• pp.87-96
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• 1993

Because of the complexity, nonlinearity and long-time delay of power plant, the star-up operation of a fossil power plant is very difficult to automate. So the start-up operation is always carried out by the skilled human operators, who utilize their knowledges and experiences for the predesigned start-up schedules and procedures. In this paper, a fuzzy logic controller is designed for the start-up operation of the power plant. And the operators experiences are modeled in terms of fuzzy sets and variables. To validate the controller, a drum-type boiler of the Seoul Power Plant is constructed via the signal flow diagram. Using the model, the suggested automatic start-up operation is verified, and the results are also presented.

• Asian Journal of Innovation and Policy
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• 제11권1호
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• pp.30-49
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• 2022

As industrialized countries transition into knowledge economies, there is a rising demand for talent and innovation. Support for start-ups through incubation, acceleration, and venture capital has turned into a key area of investment, with public and private actors searching for the next unicorn. This article examines start-up visas as an emerging policy tool in the global competition for highly innovative entrepreneurs. The study builds on a sample of eight national start-up immigration programs and applies human-capital citizenship (Ellermann, 2020) as a guiding framework. The article first proposes a conceptualization of start-up visas, suggesting that innovation and entrepreneurship also be considered in the theorization of skills. Second, the study examines the implications of start-up visas for international mobility. By focusing on the logic of entry requirements and subsequent benefits accrued through the status as a start-up founder, the findings of this study highlight the role of start-up visas in expanding privileged pathways to cross-border mobility. The article concludes with a discussion of implications for policy and research concerned with the international mobility of start-ups

• 한국자동차공학회논문집
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• 제14권3호
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• pp.58-67
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• 2006

In this paper, fuzzy logic based active ventilation system with security function is proposed and implemented. We can easily experience the situation that inner air is so hot to get start immediately after parking at summer day. Hot temperature is enough to explode a gas lighter or to suffocate a little chid. Proposed system has 1 blower and 2 axial fans to ventilate inner air. Based on the fuzzy logic, speed and direction of each fan are controlled. In addition to controlling fans, controller put down windows and adjust the periods of open time. In order to prevent the theft and security problems, IR sensors are used to detect objects. On detecting objects, controller put up windows. Experimental result shows that implemented system can be effectively ventilate inner air and reduce temperature. Proposed system can be applicable to commercial automobiles.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 B
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• pp.458-460
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• 1998

The drum level control is initiated by 1-element manual control, and then the control mode is changed to 1-element automatic control mode. Finally, the drum level control is changed to 3-element automatic control mode by the logic based on pre-defined threshold of main steam flow. In terms of plant automation, the automatic 1-element control mode is required from the start-up of boiler. In this paper, the fuzzy controller is adopted for automatic 1-element control of drum level from start-up. It is suggested that the fuzzy controller is used in 1-element control, and the fuzzy-PI cascade controller is used in 3-element control. Finally, the validity of suggested control scheme is shown via simulation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.880-886
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• 1992

There has been continuous effort to achieve total automation of the power plants. But due to complexity, nonlinearities and time-varying properties of the system, no success has been reported if conventional and/or modern control theories are applied. In spite of this, the start-up and shutdown operations are successfully performed by skilled human operators who are able to utilize a great wealth of knowledge and past experiences. In this paper, in order to automate the shutdown operation of power plants, it is proposed that the operation be performed by a more efficient method than the current used, through dividing the total process into several subprocesses, introducing checkpoints, and using fuzzy logic. For this, fuzzy logic controllers and fuzzy decision-makers are designed and the validity is shown by simulation via a set of piecewise continuous shutdown models.

• Nuclear Engineering and Technology
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• 제25권3호
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• pp.371-380
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• 1993

운전원의 언어적인 제어 논리를 이용한 모델과 무관한 제어기가 증기 발생기의 수위 제어를 위해 개발되었다. 오직 9개의 룰을 수위 오차와, 응축 수위 변화를 표현하는 유량 오차로부터 얻어졌다. 벨형의 소속함수는 민감도 분석을 통하여 조절되었고, 결과 과도 상태와 정상상태 공히 양호한 제어성능을 보였다. 저출력에서 전 출력까지의 다단계 출력 증가에 대하여, 전 운전 영역에서 좋은 제어를 보였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.746-748
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• 1999

We acquired operating data to develop a digital control system adaptable to gas turbine power plant with about 50 to 100MW. We analyzed an existing analog control logic using these data. We developed control application programs for turbine automatic start up. We showed a similar result compared with an existing analog control system by computer simulation.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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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).

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권10호
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• pp.587-594
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• 2002

A low frequency square wave electronic ballast for the high intensity discharge(HID) lamps using fuzzy logic controller is developed. This electronic ballast consists a buck converter, a low frequency square wave full bridge inverter, a high voltage pulse generator for the HID lamp ignition, an over current protection circuit and an 8-bit microcontroller. The ballast system is operated on the constant current mode during the HID lamp start-up process and the system is operated on the constant power mode during steady state. Experimental results show that the fuzzy logic control operation is carried out successfully by the 8-bit microcontroller PIC16F877 In this electronic ballast system, in spite of the limited control bandwidth caused by low operating speed of the microcontroller, the good performance in the constant lamp current characteristic is obtained. Acoustic resonance of the HID lamps can be effectively avoided because the instantaneous In lamp power is fully constant due to the low frequency square wave drive.