• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1433-1434
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• 2008

LED has gained its importance in the projection display market from very compact, micro-projectors to potentially high output, desktop systems. In both of these systems, the output levels are less than desirable. This paper describes practical recycling and multiplexing systems that provide brightness increases, and allow projectors to achieve outputs beyond its current levels.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2018년도 공동국제학술발표회
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• pp.43-43
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• 2018

• 전력전자학회논문지
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• 제4권2호
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• pp.175-183
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• 1999

PWM 컨버터에서 직류출력전압의 빠른 응답을 위해 입력 및 출력의 전력평형개념을 시스템 모델링에 도입하는 것이 바람직하다. 이 경우 시스템은 비선형이 되며 제어기 설계가 용이하지 않다. 본 논문에서는 입출력 궤환선형화 기법을 응용하여 시스템의 비선형성을 제거하였으며 그 결과 빠른 전압응답특성을 얻을 수 있었다. 또한 작은 용량의 전해커패시터를 사용하더라도 부하변동에 대해 직류출력전압을 일정하게 유지하는 것이 가능함을 보였다.

• Journal of Mechanical Science and Technology
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• 제14권1호
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• pp.57-64
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• 2000

Recent advances in the field of control theory have enabled us to design active vibration control systems for various structures. In many studies, the controller used to suppress vibration has been synthesized for the given mathematical model of structure. In these cases, the designer has not been able to utilize the degree of freedom to adjust the structural parameters of the control object. To overcome this problem, so called 'Structure/Control Simultaneous Optimization Method' is used. In this context of view, this paper is concerned with the active vibration control of bridge towers, platforms and ocean vehicles etc. Simultaneous design method is used to achieve optimal system performance. Here, a general framework for the simultaneous design problem of output feedback case is introduced based on LMI (Linear Matrix Inequality). The simulation results show that the proposed design method achieves desirable control performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.605-610
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• 1991

In inverter system for driving induction motor, the output harmonics are hamrful in induction motor drive because it leads to ripple torque and induction interference. For electrical drives using PWM(Pulsewidth Modulation) inverters and ac motors, the methods for efficiency optimal control have been developed. In this paper, two different PWM methods for inverter and voltage control technique are described. In order to reduce or minimize losses, various forms of PWM strategy such as, PM (Positive Modulation) and NM (Negative Modulation) are discussed. The results show the feasibility of obtaining practically sinusoidal output waveforms which are highly desirable in most inverter application.

• 품질경영학회지
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• 제37권3호
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• pp.123-139
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• 2009

This study examines the relative efficiency of 34 local public medical centers in Korea. In order to concretely grasp the causes of inefficiency and suggest improvement solutions, the desirable set point was established based on the actual value which needs to be improved. As a result of analysis, we determined that output must be increased while input is held constant in order to improve effectiveness through the actual value and set point. Efficiency cannot be achieved if input is augmented solely to increase output. Also, to increase output, the medical centers need to improve their quality without increasing any input for customer visits and hospitalizations. Further, in order to strategically promote effectiveness and efficiency of local public medical centers, these medical centers must focus on input resource and patient interchange through the mutual cooperation with local private hospitals and university medical centers.

• 한국정밀공학회지
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• 제13권7호
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• pp.59-65
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• 1996

A major problem in automation of turning operations is the difficulty in obtaining a sufficient and reliable chip control. Therefore it becomes desirable to find a method which can detect the chip form. Newly born chips in usual metal cutting radiate infrared rays. When such chips run out of cutting point quickly, the radiated energy from the zone around the tool is low compared with that of the case when long tangled chips are staying around the tool. The difference in chip pattern can be detected from the output of pyrometer. But, strictly speaking, only the output of pyrometer does not identify the chip form because that is the removal of chip. Therefore, in this paper, a method of the identification of chip form using output of pyrometer and fuzzy inference is developed.

• 전기학회논문지
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• 제61권11호
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• pp.1571-1577
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• 2012

This paper presents a method for assessing the voltage sag performance of power system involving wind power generation. Wind power generation is considered as one of the most desirable renewable energy sources. However, wind power generation have uncertain energy output and it is difficult to control the output. The existing methods of voltage sag assessment are not reflected the characteristics of wind power generation. Therefore, in order to more accurately assess the voltage sag performance, the probability of wind power operation is evaluated. In this paper, the probability is determined by combining the wind speed model with the output curve of wind turbine. The probability of wind power operation is reflected as a parameter in voltage sag assessment. The proposed method can provide more accurate results of voltage sag assessment for the case involving the wind power generation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 추계학술대회 논문집
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• pp.64-69
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• 2004

This paper deals with an algorithm for controlling ac output voltage of Z-source inverter using Modified SVPWM (abbreviated as MSVPWM). Unlike the conventional space vector pulse width modulation, MSVPWM has one extra shoot-through zero time $T_{sh}$. During shoot-through zero time, both switches in a leg are conducted simultaneously in order to boost inverter output voltage to any desirable value regardless the line voltage. The algorithm to control linearly the capacitor voltage is suggested to improve the performance of Z-source inverter system. The performance of Z-source inverter using above algorithms is demonstrated in simulation results using PSIM. Index terms-Z-source inverter (ZSI), shoot-through time, three-phase carrier-based PWM, space vector PWM (SVPWM), modified space vector PWM (MSVPWM).

• 대한전자공학회논문지
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• 제25권12호
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• pp.1625-1632
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• 1988

This paper aims not only to introduce the concept of linear singular systems, geometric structure, and feedback but also to provide applications of the multivariable linear singular system theories to electric circuits which may appear in some electronic equipments. The impulsive or discontinuous behavior which is not desirable can be removed by the set of admissible initial conditions. The output-nulling supremal (A,E,B) invariant subspace and the singular system structure algorithm are applied to this double-input double-output electric circuit. The Weierstrass form of the pencil (s E-A) is related to the output-nulling supremal (A,E,B) invariant subspace from which the time domain solutions of the finite and the infinite subsystems are found. The generalized Lyapunov equation for this application with feedback is studied and finally, the use of orthogonal functions in singular systems is discussed.