• 대한교통학회지
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• 제20권7호
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• pp.177-183
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• 2002

현재 국내 VMS 운영은 대체로 소극적 정보제공에 머물고 있으며, 정보제공 우선순위. 조합 가능한 메시지 집합 등이 포함된 간단한 형태의 지식기반 추론엔진 방식에 의하고 있다. 또한 VMS 관련 연구도 해당도로의 상황을 정확히 검지하고 예측하는 방법론 개발에 집중되어 있다. 그러나 VMS도 적극적 운영을 통하여 교통관리의 수단으로 활용해야 하며, 이에 있는 그대로 상황을 전달하는 현 Practice에서 진일보한 전략적 정보제공 기술이 개발되어야 한다. 본 연구에서는 네트워크 차원의 교통관리를 목적으로 한 VMS 자동제어 알고리즘을 제안하였다. 외란의 불확실성과 모형의 정확도에 강한(robust) 피드백 제어방식을 채택하였고, 알고리즘은 시스템 최적 달성을 목표로 설정한 여유용량 균등화 Regulator와 VMS Display 모듈로 구성된다. 여유용량의 산정은 도로용량편람의 용량 개념과 차별화 되는 개념을 제안하였으며 이 부분에 대한 구체적 산정방식의 개발은 향후과제로 남겨두었다. 두 개의 대안경로로 구성된 실제 도로망에 대한 모의실험을 통하여. 여유용량균등화 Regulator에 의한 통행 재배분 효과를 제한적으로나마 살펴보았다. 그러나 VMS Display Strategy 모듈에 의한 실제 통행배분 행태는 모의실험의 한계성으로 인하여 검증하지 못하였으며 이를 향후과제로 남겨두었다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1361-1362
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• 2009

We challenge to use reactive mesogen optical elements which can be coated inside LC cell. The reactive mesogens as retarder barrier requirements can be achieved between a high performance 2D mode and a low cross talk stereoscopic 3D mode. The fabrication of a 10.1" diagonal LCD which co-operates with a polarizer to from a parallax barrier, is described. In addition, the parallax barrier of reactive mesogens can easily control in mass production and can thus be coated as extremely LC cell, significantly reducing the thickness of LCD. Finally, we have successed to design a switchable 2D/3D displays using reactive mesogen optical elements which can be achieved 3D displays within glasses.

• 반도체디스플레이기술학회지
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• 제22권3호
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• pp.52-61
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• 2023

We designed a novel ultra-miniaturized microcolumn structure having an stigmator to significantly improve throughput per unit time, which is the biggest disadvantage of microcolumns. We adopted the structure of the stigmator in the form of an electrostatic octupole electrode, and used an electrostatic quadrupole deflector with a relatively simple structure considering the increase in wiring due to the introduction of the stigmator. We have dramatically reduced the effect of astigmatism that occurs when the electron beam probe is scanned to the periphery of the target by introducing the stigmator between the control electrode and the deflector. As our numerical analysis simulation results, the field of view obtained as a result of this study is about 46.3% improved compared to our previous study, and the electron beam probe size of less than 10 nm was achieved in the entire field of view.

• 전기학회논문지
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• 제61권2호
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• pp.303-311
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• 2012

In this study, we introduce a dynamic process model as well as the design methodology of optimized fuzzy controller for its efficient application to vacuum production system to produce a semiconductor, solar module and display and so on. In a vacuum control field, PID control method is widely used from the viewpoint of simple structure and preferred performance. But, PID control method is very sensitive to the change of environment of control system as well as the change of control parameters. Therefore, it's difficult to get a preferred performance results from target system which has a complicated structure and lots of nonlinear factors. To solve such problem, we propose the design methodology of an optimized fuzzy PID controller through a following series of steps. First a dynamic characteristic of the target system is analyzed through a series of experiments. Second the process model is built up and its characteristic is compared with real process. Third, the optimized fuzzy PID controller is designed using genetic algorithms. Finally, the fuzzy controller is applied to target system and then its performance is compared with that of other conventional controllers(PID, PI, and Fuzzy PI controller). The performance of the proposed fuzzy controller is evaluated in terms of auto-tuned control parameters and output responses considered by ITAE index, overshoot, rise time and steady state time.

• 대한간호학회지
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• 제51권4호
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• pp.465-477
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• 2021

Purpose: This study aimed to evaluate the effects of head monted display based home-visits virtual reality simulation (HVRS) program developed for undergraduate nursing students. Methods: A nonequivalent control group with a non-synchronized design was utilized and 84 participants (experimental group, 44; control group, 40) were recruited from August 31, 2020 to November 8, 2020 in Gwangju metropolitan city. The HVRS program consisted of scenarios of three nursing cases, hypertension, diabetes mellitus, and stroke. Data were analyzed SPSS version 25.0 for Windows. Results: At the completion of HVRS, significant differences were found between groups in knowledge of home-visits (t = 4.73, p < .001), self-confidence (t = 6.63, p < .001), self-efficacy (t = 3.13, p = .002), and clinical competency (t = 4.13, p < .001). No significant difference was shown between groups in nursing knowledge about strokes, a subcategory of knowledge pertaining to home visits. Conclusion: The HVRS program developed for undergraduate nursing students is effective in improving knowledge of home-visits, self-confidence, self-efficacy, and clinical competency for nursing students.

• 반도체디스플레이기술학회지
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• 제13권4호
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• pp.65-70
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• 2014

This paper is to improve the problem of the LED dimming control system using the conventional PWM and DAC method. The conventional PWM method controls the average current to switch dimming signal. This method generates the flicker when controlling at a low current. In order to solve the problem, this system prevents the flicker with the DAC method. The LED is lit at micro-current flowing in the LED. And offset voltage is generated in the output of the DAC when the DAC output is very low voltage as 0V. This was resolved by the voltage drop of the output voltage to construct a negative offset circuit. In addition, the LED current can't flow as set values because of overheating of FET. In order to solve the problem, the 16 bits ADC in the microprocessor is a more accurate current control receives the LED current in comparison with the set value. Therefore, the LED dimming control system proposed in this paper showed the accurate and reliable more than conventional systems.

• 풍력에너지저널
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• 제2권1호
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• pp.90-96
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• 2011

The purpose of this paper is to describe the control system for optimal performance of 2MW gearless PMSG wind turbine system, and to afford some techniques of the algorithm selection and design optimization of the wind turbine control system through analysis of load calculation and control characteristic. Wind turbine control system is composed of the main control system and remote control and monitoring system. The main control system is industrial PC based controller, and the remote control and monitoring system is a server based computer system. The main control system has a supervisory control of the wind turbine with operation procedures and power-speed control through the torque control by pitch angle. There are some applications to optimize the wind turbine system at the starting mode with increasing of rotor speed, and cut-in operating mode to prevent trundling cut-in and cut-out, a gain scheduling of pitch PID controller, torque scheduling and limitation of generation power by temperature limitation or remote command by remote control and monitoring system. Also, the server operation program of the remote control and monitoring system and the design of graphical display are described in this paper.

• 반도체디스플레이기술학회지
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• 제18권3호
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• pp.82-87
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• 2019

One of the most critical aspects of the semiconductor industry is the quality of the wafer surface. And the vibrations of wafer grinder are supposed to be the most dominant factors to damage the wafer surface quality. In this study, structure of a wafer grinder has been analyzed through experiments and computer simulations to figure out the main reasons of the vibrations. And the design alterations based on the analysis were applied to identify the effects of those alterations on the vibration suppression. The result shows that the design alterations can effectively suppress about 90% of the vibrations.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2000년도 추계학술대회
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• pp.99-103
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• 2000

최근 많은 분야에서 사용피고 있는 소형 전광판을 이용하여 원거리에서도 메시지 전달이 가능한 광고용 전광판을 제작하였다. FSK Modem과 RF-Module을 이용하여 실시간으로 광고의 내용을 바꾸는 것을 원칙으로 구현하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1665-1670
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• 2007

The On-Board Computer System Used for rolling stocks is one of the core equipments in trains, which deals with collecting real-time data of a train to display and record the train's status, control the train, and assist the driver and maintenance function. To design control software for such complex control system, in this paper UML based modeling technique is applied. A behaviorally expressive set of diagrammatic languages for modeling object-oriented systems is presented. It constitutes the constructive subset of UML, and also it enables model execution and full code synthesis.