• 조명전기설비학회논문지
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• 제20권6호
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• pp.35-42
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• 2006

규모가 큰 제철소는 전기로를 포함한 비선형 부하를 가지고 있다. 이들 비선형 부하는 고조파 전류를 발생 시키고, 전력 계통의 전압을 왜곡시킨다. 본 논문에서는 전기로 부하의 고조파 현장 측정, 고조파 저감을 위해 수용가 모선에 동조 필터 적용과 국제 고조파 관리 기준인 IEC 61000-3-6과 IEEE Std. 519에 의한 고조파 평가를 심도 있게 분석한다. 고조파 해석 프로그램인 EDSA는 사례연구에 시뮬레이션 도구로 사용되었다.

• 조명전기설비학회논문지
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• 제22권5호
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• pp.95-102
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• 2008

일반 가정집 부하는 컴퓨터, 비디오, 냉장고, 마이크로웨이브 오븐, TV, 오디오 등의 많은 비선형 부하를 가지고 있다. 이들 비선형 부하는 고조파 전류를 발생시키고, 전력계통의 정현파 전압을 왜곡시킨다. 고조파 측정 결과로 고조파는 시간에 따라 변하는 특성이 관측되었다. 시간에 따라 변하는 고조파를 해결하기 위해서 쓰이는 가장 보편적인 방법은 누적확률을 사용하는 것이다. 본 논문에서는 일년동안 일반 가정집 부하의 고조파 측정을 하고, 현존하는 가정집 부하의 고조파 수준과 미래의 고조파 영향을 예측하기 위한 목적의 조사를 심도 있게 다루고자 하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.122-127
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• 2003

In this paper, an adaptive predistortion scheme is proposed to compensate nonlinear distortions caused by high power amplifiers (HPA) in OFDM systems. A complex Wiener-Hammerstein model (WHM) is used to describe input-output relationship of HPA with linear dynamics. The predistorter is directly identified by complex power series model with memory, which is an approximate inverse of the HPA expressed by the WHM. The effectiveness of the proposed adaptive compensation scheme is validated by numerical simulation for 64QAM-OFDM systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.1085-1087
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• 2001

This paper deals with single-phase unified power quality conditioner, which aims at the integration of series-active and shunt-active tilter. The series filter is used to compensate for the voltage distortions and the shunt filter is used to provide reactive power and counteract the harmonic current injected by the load. Also, the voltage of the DC link capacitor is controlled to a desired value by the shunt active filter. In order to verify the performance of the proposed conditioner, computer simulations using MATLAB/SIMULINK were demonstrated. The results confirm that the proposed conditioner shows excellent performance to eliminate the harmonics and voltage flickers generated at the singe-phase nonlinear load.

• 전자공학회논문지S
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• 제34S권1호
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• pp.94-104
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• 1997

Most color imaging devices often exhibit color distortions due to the differences in realizable color gamuts and nonlinear characteristics of their components. In order to minimize color differences, it is desirable to apply color correction techniques. Th efirst step of color correction is to select the subset of the color coordinates representing the input color space. Th eselected subset serves as so called color samples to model the color distortion of a given color imaging device. The effectiveness of color correction is determined by the color sampels utilized in the modeling as well as the applied color correction technique. This paper presents a new selection method for color samples based on gentic algorithm. In the proposed method, structure of strings are designed so that the selected color samples fully represent the characteristics of color imaging device and consist of distinct color coordinates. To evaluate the performance of the selected color samples, they ar etuilized for three different color correction experiments. The experimentsal results are comapred with the crresponding results obtianed with the equally spaced color samples.

• International journal of advanced smart convergence
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• 제1권1호
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• pp.6-13
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• 2012

An improved algorithm for image quality assessment is presented. First a simple model of human visual system, consisting of a nonlinear function and a 2-D filter, processes the input images. This filter has one user-defined parameter, whose value depends on the reference image. This way the algorithm can adapt to different scenarios. In the next step the average value of locally computed correlation coefficients between the two processed images is found. This criterion is closely related to the way in which human observer assesses image quality. Finally, image quality measure is computed as the average value of locally computed correlation coefficients, adjusted by the average correlation coefficient between the reference and error images. By this approach the proposed measure differentiates between the random and signal dependant distortions, which have different effects on human observer. Performance of the proposed quality measure is illustrated by examples involving images with different types of degradation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.38-41
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• 2002

Increasing of the use nonlinear power electronics equipments, power conditioning systems have been researched and developed for many years to compensate the harmonic disturbances and the reactive power. The main function of power conditioning systems is to reduce harmonic distortions, since extensive surveys quantify the problems associated with electric networks haying non-linear loads. The main function of power conditioner compensates the current instead of the voltage. Therefore the inverter used in power conditioner ismostley current controlled type. In this paper, the proposed current control algorithm is analyzed and discussed about how to design the controller which can apply power conditioning operation for grid-connective PV power system. And also proposed control system. To verify the proposed current control algorithm, a comprehensive evaluation with theoretical analysis, simulation results is presented.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 추계학술대회 논문집
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• pp.226-229
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• 2003

Increasing of the use nonlinear power electronics equipments, power conditioning systems have been researched and developed for many years to compensate the harmonic disturbances and the reactive power. The main function of power conditioning systems is to reduce harmonic distortions, since extensive surveys quantify the problems associated with electric networks having non-linear loads. The main function of power conditioner compensates the current instead of the voltage. Therefore the inverter used in power conditioner is mostly current controlled type. In this paper, the proposed current control algorithm is analysed and discussed about how to design the controller which can apply power conditioning operation for grid-connective PV power system. And also proposed control system. To verify the proposed current control algorithm, a comprehensive evaluation with theoretical analysis, simulation, experiment results is presented.

• Korean Journal of Hydrosciences
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• 제8권
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• pp.41-56
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• 1997

A new routing computer model for the symmetric compound channel called the ASRMCS(Apparent Shear Force Muskingum-Cunge Method in Symmetry) has been developed. The Muskingum-Cunge routing method is adapted. The Apparent Shear Force (ASF) between the deep main channel and the shallow floodplan flow is introduced while the flow is routed. The nonlinear parameter method is applied. The temporal and spatial increments are varied according to the flow rate. The adaptation of above schemes is tested against the routed hydrographs using the DAMBRK model. The results of general routing practice of Muskingum-Cunge Method(GPMC) are also compared with those of above two models. The results of the new model match remarkably well with those of DAMBRK. The routed hydrographs show a smooth variation from the inflow boundary condition without any distortions caused by the difference of cross-section shape. However, the results of GPMC, showing early rise and fall of routed hydrograph, have considerable differences from those of the ASFMCS and DAMBRK.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권6호
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• pp.718-727
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• 2014

In a wireless communications system, a predistorter is often used to compensate for the nonlinear distortions that result from operating a power amplifier near the saturation region, thereby improving system performance and increasing the spectral efficiency for the communication channels. This paper presents a new VLSI design for the polynomial digital predistorter (DPD). The proposed DPD uses a Coordinate Rotation Digital Computing (CORDIC) processor and a PD process with a fully-pipelined architecture. Due to its simple and regular structure, it can be a competitive design when compared to existing polynomial-type and approximated DPDs. Implementing a fifth-order distorter with the proposed design requires only 43,000 logic gates in a $0.35{\mu}m$ CMOS standard cell library.