• 한국전자파학회:학술대회논문집
• /
• 한국전자파학회 2001년도 종합학술발표회 논문집 Vol.11 No.1
• /
• pp.267-271
• /
• 2001

다이오드의 소신호 및 대신호 파라미터 추출은 DC 해석, 외부 기생 소자 추출, 마지막으로 5-파라미터에 의한 내부소자 추출로 이루어진다. DC IV-곡선과 S-파라미터의 curve-fitting으로 내부 파라미터를 구하였고 외부 기생소자는 바이어스에 따라 변하지 성질을 이용하였다. 사용된 소자는 Schottky diode는 SIEMENS사의 BAS125를, Varactor diode는 SONY사의 1t362를, PIN diode는 Hitachi사의 HVM14S를 모델로 사용하였다. 실측을 위해 사용된 소자는 각각 HP사의 HSMS-2822, SONY사의 1t362, HP사의 HSMP-3834을 이용하여 측정하였다.

• 음성과학
• /
• 제1권
• /
• pp.285-293
• /
• 1997

This paper was constructed to investigate strange attractor in considering speech which is regarded as chaos in that the random signal appears in the deterministic raising system. This paper searches for the delay time from AR model power spectrum for constructing fit attractor for speech signal. As a result of applying Taken's embedding theory to the delay time, an exact correlation dimension solution is obtained. As a result of this consideration of speech, it is found that it has more speaker recognition characteristic parameter, and gains a large speaker discrimination recognition rate.

• 융합신호처리학회 학술대회논문집
• /
• 한국신호처리시스템학회 2003년도 하계학술대회 논문집
• /
• pp.238-241
• /
• 2003

This paper presents a nonlinear least squares decision feedback equalizer Bilinear systems are attractive because of the ability to approximate a large class of nonlinear systems efficiently. The nonlinearity of channel is modeled using a bilinear system. The algorithms are derived by using the QR decomposition for minimization covariance matrix of prediction error by applying Givens rotation to the bilinear model. Result of computer simulation experiments that compare the performance of the bilinear DFE to two other DFE's in eliminating the intersymbol interference caused by a nonlinear channel are presented In the paper.

• Journal of Electrical Engineering and Technology
• /
• 제11권4호
• /
• pp.951-960
• /
• 2016

Tower insulators in electric power transmission network play a crucial role in preserving the reliability of the system. Electrical utilities frequently face the problem of flashover of insulators due to pollution deposition on their surface. Several research works based on leakage current (LC) measurement has been already carried out in developing diagnostic techniques for these insulators. Since the LC signal is highly intermittent in nature, estimation of pollution severity based on LC signal measurement over a short period of time will not produce accurate results. Reports on the measurement and analysis of LC signals over a long period of time is scanty. This paper attempts to use Random Forest (RF) classifier, which produces accurate results on large data bases, to analyze the pollution severity of high voltage tower insulators. Leakage current characteristics over a long period of time were measured in the laboratory on porcelain insulator. Pollution experiments were conducted at 11 kV AC voltage. Time domain analysis and wavelet transform technique were used to extract both basic features and histogram features of the LC signal. RF model was trained and tested with a variety of LC signals measured over a lengthy period of time and it is noticed that the proposed RF model based pollution severity classifier is efficient and will be helpful to electrical utilities for real time implementation.

• Journal of Positioning, Navigation, and Timing
• /
• 제10권4호
• /
• pp.363-369
• /
• 2021

Since the Global Navigation Satellite System (GNSS) signal received from the low Earth orbit (LEO) satellite is only affected by the upper ionosphere, the magnitude of the ionospheric delay of Global Positioning System (GPS) signal received from ground user is different. Therefore, the ground-based two-dimensional ionospheric model cannot be applied to LEO satellites. The NeQuick model used in Galileo provides the ionospheric delay according to the user's altitude, so it can be used in the ionospheric model of the LEO satellites. However, the NeQuick model is not suitable for space receivers because of the high computational cost. A simplified NeQuick model with reduced computing time was recently presented. In this study, the computing time of the NeQuick model and the simplified NeQuick model was analyzed based on the GPS Klobuchar model. The NeQuick and simplified NeQuick model were applied to the GNSS data from GRACE-B, Swarm-C, and GOCE satellites to analyze the performance of the ionospheric correction and positioning. The difference in computing time between the NeQuick and simplified NeQuick model was up to 90%, but the difference in ionospheric accuracy was not as large as within 4.5%.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
• /
• pp.534-538
• /
• 1987

State-space techniques are employed to derive an equivalent nonlinear recurrent time-domain model that describes the series resonant converter behavior exactly. This model is employed effectively to analyze large signal behavior by propagating the recurrent equation and matching boundary conditions through digital computation. The model is verified with a laboratory converter for a steady-state operation.

• 대한전기학회논문지:전력기술부문A
• /
• 제51권11호
• /
• pp.577-584
• /
• 2002

This paper presents a novel approach based on eigenvalue perturbation of augmented matrix(AMEP) to estimate the eigenvalue for variation of controller parameter. AMEP is a useful tool in the analysis and design of large scale power systems containing many different types of exciters, governors and stabilizers. Also, it can be used to find possible sources of instability and to determine the most sensitivity parameters for low frequency oscillation modes. This paper describes the application results of AMEP algorithm with respect to all controller parameter of KEPCO systems. Simulation results for interarea and local mode show that the proposed AMEP algorithm can be used for turning controller parameter, and verifying system data and linear model.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2012년도 춘계학술대회 논문집
• /
• pp.929-932
• /
• 2012

Beat map shows the distribution property of the beating sound in the bell structure. Using the beat map, beat control and beat estimation are available. To draw the beat map, mode pair parameters of the bell are required. However, in case of large bell which is struck by a heavy wooden hammer, it is very difficult to measure the excitation force and to obtain the mode pair parameters. In this paper, we determined the mode pair parameters of the bell from the transmissibility between the roving signal and reference signal, using ODS(operational deflection shape) method. The mode pair data are input to the theoretical model of the beat response and beating waves are generated on the bell circumference. All the numerical and beat map drawing procedures are automatized using Matlab. Finally, the reliability of the beat map generated by the program is verified.

• E2M - 전기 전자와 첨단 소재
• /
• 제9권9호
• /
• pp.969-977
• /
• 1996

본고에서는 여러가지 Wide Band-gap중에서 특히 최근에 많은 관심을 끌고 있는 GaN와 4H-SiC, 6H0SiC의 전자기적 물성을 소개하고 현재 이들로부터 제작된 prototype소자들의 성능을 비교함으로써 그 발전현황을 알아보기로 한다. 본고에서 관심을 두는 소자분야는 광전소자(optoelectronic devices)라기보다는 고주파 고출력용 전력소자임을 밝힌다. 아울러 GaN로부터 제작된 MESFET(MEtal Semiconductor Field-Effect Transistor)소자의 고주파 대역에서의 Large-Signal특성을 Device/Circuit Model을 통하여 실험치와 비교하여보고 이로부터 최적화된 channel 구조를 갖는 소자구조에서의 RF특성을 조사한다.

• 한국정보통신학회논문지
• /
• 제8권3호
• /
• pp.563-569
• /
• 2004

유성버스트 통신로 해석에 사용되는 공식은 일반적으로 트레일에 대해 전파를 입사 후 반사된 전파의 특성 값을 이용하여 얻을 수 있다. 수치해석 시뮬레이션은 전계의 복소 공간 구조에서 나타낸다. 전계 강도에 대한 시작용은 비정적 모델을 연산하여 얻을 수 있다. 이러한 시작용은 기본적으로 유성 트레일의 매개 변수에 따라 변화하고 또한 이는 단일 산란시 신호 강도의 시종속에 많은 변수가 있다는 것을 나타낸다. 실제적으로 저밀도의 유성 트레일에서 사용하는 근사 매개 변수는 고밀도 유성과 같이 지속시간이 오래 유지되는 경우에도 적용이 가능하다.