• 약학회지
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• 제44권4호
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• pp.308-314
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• 2000

Logarithmic transformation of pharmacokinetic parameters is routinely used in bioequivalence studies based on pharmacokinetic and statistical grounds by the United States Food and Drug Administration (FDA), European Committee for Proprietary Medicinal Products (CPMP), and Japanese National Institute of Health and Science (NIHS). Although it has not yet been recommended by the Korea Food and Drug Administration (KFDA), its use is becoming increasingly necessary in order to harmonize with international standards. In the present study, statistical procedures for the analysis of a bioequivalence based on the log transformation and a related SAS procedure were demonstrated in order to aid the understanding and application. The AUC parameters used in this demonstration were taken from the previous bioequivalence study for two aceclofenac tablets, which were performed in a single-dose crossover design. Analysis of variance (ANOVA), statistical power to detect 20% difference between the tablets, minimum detectable difference and confidence intervals were all assessed following log-transformation of the data. Bioequivalence of two aceclofenac tablets was then estimated based on the guideline of FDA. Considering the international effort for harmaonization of guidelines for bioequivalence tests, this approach may require a further evaluation for a future adaptation in the Korea Guidelines of Bioequivalence Tests (KGBT).

• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1605-1614
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• 2013

This paper presents a probabilistic methodology for small signal stability analysis of power system with correlated wind sources. The approach considers not only the stochastic characteristics of wind speeds which are treated as random variables with Weibull distributions, while also the wind speed spatial correlations which are characterized by a correlation matrix. The approach based on the 2m+1 point estimate method and Cornish Fisher expansion, the orthogonal transformation technique is used to deal with the correlation of wind farms. A case study is carried out on IEEE New England system and the probabilistic indexes for eigenvalue analysis are computed from the statistical processing of the obtained results. The accuracy and efficiency of the proposed method are confirmed by comparing with the results of Monte Carlo simulation. The numerical results indicate that the proposed method can actually capture the probabilistic characteristics of mode properties of the power systems with correlated wind sources and the consideration of spatial correlation has influence on the probability of system small signal stability.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1033-1036
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• 2002

This paper introduces a control method of series active power filter that compensate harmonic currents and eliminate a neutral line current in 3 phase 3 wire and 3 phase 4 wire power system with harmonic voltage source. These harmonic currents and neutral line current are caused by a nonlinear loads such as diode rectifiers and thyristor converters. Proposed methode extracts a voltage reference directly from performance function without phase transformation. Therefore, the control method is simpler than any other conventional methods. Experimental results for 3-phase 3-wire and 3-phase 4-wire series active power filter system were shown to verify the effectiveness of this control method.

• 한국소음진동공학회논문집
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• 제17권7호
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• pp.624-631
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• 2007

PFA (power flow analysis) has been recognized as a useful method in vibration analysis of medium-to-high frequency ranges. Until now, PFA method has been developed for steady-state vibration problems. In this paper, PFA method has been expanded to transient problem. New energy governing equations are derived considering time dependent terms in beam and plate. Analytic solutions of those equations are found in simple beam and plate, and are verified by comparing with modal solutions.

• Journal of Power Electronics
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• 제15권6호
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• pp.1664-1672
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• 2015

This paper proposes a series arc fault detection algorithm which incorporates peak voltage and harmonic current detectors for single-phase boost power factor correction (PFC) rectifiers. The series arc fault model is also proposed to analyze the phenomenon of the arc fault and detection algorithm. For arc detection, the virtual dq transformation is utilized to detect the peak input voltage. In addition, multiple combinations of low- and high-pass filters are applied to extract the specific harmonic components which show the characteristics of the series arc fault conditions. The proposed model and the arc detection method are experimentally verified through a boost PFC rectifier prototype operating under the grid-tied condition with an artificial arc generator manufactured under the guidelines for the Underwriters Laboratories (UL) 1699 standard.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.332-334
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• 2005

This paper presents a dynamic simulation of the unified power flow controller (UPFC) using a current injection method. Flexible AC Transmission System (FACTS) devices give more flexibility of control for security and economic operation of power systems. Diffculties of modeling UPFC in the conventional dynamic simulation programs arise from the fact that the injected voltage by the series inverter is superimposed on the shunt inverter side voltage. A solution can be a current injection method, in which a serial part of UPFC is converted to a parallel equivalent circuit using source transformation, and two current sources affect each other at every time step. To verify efficiency of this method, the proposed model is applied for the transient analysis of an example power system.

• 한국지능시스템학회논문지
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• 제10권5호
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• pp.478-486
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• 2000

본 논문에서는 CMOS 디지털 회로상의 플립플롭의 위치를 이동시키는 리타이밍 변환에 유전자 알고리즘을 적용하여 회로의 최적 동작 속도를 유지하면서 전력의 소모를 줄일 수 있는 설계 방법을 제안한다. 제안된 설계 방법은 최적 속도를 구현하는 리타이밍 단계와 유전자 알고리즘이 적용되는 저전력 리타이밍의 두 단계로 이루어진다. 제안된 저전력 리타이밍 설계 도구를 예제 회로의 설계에 적용하고 설계된 회로의 성능을 Synopsys시의 Design Analyzer로 평가한 결과, 임계 경로 지연은 약 30~50% 가량 감소하였으며 동적 전력 소모는 약 1.4~18.4% 가량 감소함을 관찰하였다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 추계종합학술대회
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• pp.315-319
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• 2003

본 논문은 Custom Power의 입력 전압 Sag 보상을 위해 사용되는 PWM Boost AC-AC 컨버터의 정적 특성 및 동적 특성의 모델링 및 해석을 다룬다. 특히 회로 DQ 변환 기법을 사용하여 기본파 영역에서 시스템의 특성을 모두 포함하는 등가회로를 구하고, 전압이득과 입력역률에 대한 해석적인 결과를 도출한다. 또한, 제어의 관점에서 유용한 일정한 동작점 하에서의 선형화된 상태방정식을 구한다. 끝으로, 시뮬레이션을 통하여 제안된 등가회로 모델링과 해석이 타당함을 확인하였다.

• International Journal of Automotive Technology
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• 제2권1호
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• pp.33-38
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• 2001

The noise generated from a treadband mechanism of a tire has been the subject of this research. In particular, the treadband has been treated as an infinite tensioned beam resting on an elastic foundation which includes damping. The main objective is here to predict the sound power generated from a system mentioned above by locating harmonic point forces representing the excitation of treadband at the contact patch. It is possible to predict the sound power radiated from this structure by wavenumber transformation techniques. To find out the minimum radiated sound power, All parameters were varied. Thus this model can be used as a tire design guide for selecting parameters which produce the minimum noise radiation.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권8호
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• pp.536-543
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• 2000

The photovoltaic power generation system has a great future as clean energy instead of fossil fuel which has many environmental problems such as exhausted gas or air pollution. In a utility interactive photovoltaic generation system, a three-phase inverter is used for the connection between the photovoltaic array and the utility. This paper present a three phase inverter for photovoltaic power system with current controller, voltage controller, PLL Control system and the Phase detector of Interactive Voltage by using dq transformation. The proposed inverter system provides a sinusoidal ac current for domestic loads and the utility line with unity power factor.