• 한국인터넷방송통신학회논문지
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• 제15권1호
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• pp.261-267
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• 2015

다층 격자구조에서 전파하는 평면파들의 회절특성을 나타내는 고유치 문제는 모드 확장 원리에 의하여 정확하게 설명할 수 있다. 그런 모드 확장 원리들에 의존하는 모드 해들은 간단한 회로이며 일반적인 형태인 등가 전송선로 망에 의하여 분석할 수 있다. 이 해석법은 어떤 조건에서든 필드들의 격자 회절과정에 대한 상당한 물리적 직관성을 제공하는 해석적인 특성을 준다. 특히, 등가 전송선로 망은 다른 해석법들에서 해석적으로 구할 수 없는 회절 격자구조의 산란특성, 방출효과 그리고 다른 광학적 특성들을 체계적으로 평가하기 위한 컴퓨터 알고리즘의 템플릿으로서 사용될 수 있다. 본 논문에서 제안한 정확한 해석법의 타당성을 입증하기 위하여 앞서 연구한 논문들의 결과를 수치해석적으로 비교 분석하였다. 그 결과 본 논문에서 얻은 내용과 잘 일치함을 확인할 수 있었다.

• 센서학회지
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• 제15권1호
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• pp.34-39
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• 2006

This study provides the electrical model of combustible catalytic gas sensor. Physical characteristics such as thermal behavior, resistance change were included in this model. The finite element method analysis for sensor device structure showed that the thermal behavior of sensor is expressed in a simple electrical equivalent circuit that consists of a resistor, a capacitor and a current source. This thermal equivalent circuit interfaces with real electrical circuit using two parts. One is 'power to heat' converter. The other is temperature dependent variable resistor. These parts realized with the analog behavior devices of the SPICE library. The gas response tendency was represented from the mass transferring limitation theory and the combustion theory. In this model, Gas concentration that is expressed in voltage at the model, is converted to heat and is flowed to the thermal equivalent circuit. This model is tested in several circuit simulations. The resistance change of device, the delay time due to thermal capacity, the gas responses output voltage that are calculated from SPICE simulations correspond well to real results from measuring in electrical circuits. Also good simulation result can be produced in the more complicated circuit that includes amplifier, bios circiut, buffer part.

• 전력전자학회논문지
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• 제13권1호
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• pp.46-54
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• 2008

본 논문에서는 연료전지나 배터리 및 슈퍼커패시터 등의 전기화학적 전력기기의 임피던스 모델링에 적합한 저가의 임피던스 분광 시스템을 설계하고 구현하였다. 제안된 시스템은 간단한 센서회로 및 상용 DAQ(Data Acquisition) Board와 강력한 HMI(Human-Machine Interface)를 지원하는 그래픽 언어인 LabVIEW 소프트웨어를 이용하여 구성되었고 고가의 EIS(Electrochemical Impedance Spectroscopy) 장비를 대체하여 널리 사용될 수 있을 것으로 기대된다. 또한, 제안된 시스템에서는 Lock-in Amplifier를 이용함으로써 노이즈(Noise)가 많은 환경에서도 측정 주파수 성분의 정확한 측정이 가능하게 하였다. 제안된 시스템을 이용하여 Ballard Nexa 1.2kW PEM 연료전지 스택의 주파수별 임피던스를 측정하였고, 이를 바탕으로 한 등가 임피던스 모델도 제안된다. 제시된 모델과 개발된 장비의 유용함은 리플전류에 의한 연료전지 스택의 교류 손실 측정을 통해 증명된다.

• 한국산학기술학회논문지
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• 제7권6호
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• pp.1106-1115
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• 2006

본 논문은 다층기판으로 구현된 마이크로스트립 전송선로와 여기에 결합된 결함접지구조의 초고주파 특성 및 모델링에 대하여 기술하고 있다. 단층 마이크로스트립 전송선로와 결함접지구조를 지닌 기본형 구조에, 제 2의 유전체 층을 결함접지구조가 있는 바닥 접지면 아래에 적층하여 다층기판 속의 결함접지구조를 형성하였다. 그리고 제2의 유전체 층의 유전율과 두께를 서로 달리해 가면서 초고주파 전송특성을 보고 추가된 유전체 층에 의한 등가회로의 변화를 등가회로 모델링을 통하여 분석하였다. 본 논문에서 제안된 방법에 따르면 적층된 제 2의 유전체 층에 의한 등가회로의 변화를 따로 확인할 수 있어서 추후 초고주파 회로에 유익하게 응용될 수 있다.

• Journal of international Conference on Electrical Machines and Systems
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• 제3권2호
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• pp.116-120
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• 2014

3-phase Induction machines are being used in industry and dq transformation from 3 phase of a, b, c is commonly used to analyze these machines. The equivalent circuits of d and q axis are however generally cross coupled and not simple to analyze. In this study, an analysis method of 3ph induction motor considering current regulator using dq transformation and matrix vector is proposed and it can explain the 3ph induction motor physically. This model does not need the separating process of d and q components. With this technique, the model becomes simple, is easy to understand in physical, and can get the same results with those from the other dq models. These simulation results of the proposed model are compared with those of other models for the conformation of the proposed method.

• ETRI Journal
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• 제23권1호
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• pp.23-32
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• 2001

Examination of the statistical variation of integrated passive components is crucial for designing and characterizing the performance of multichip module (MCM) substrates. In this paper, the statistical analysis of parallel plate capacitors with gridded plates manufactured in a multilayer low temperature cofired ceramic (LTCC) process is presented. A set of integrated capacitor structures is fabricated, and their scattering parameters are measured for a range of frequencies from 50 MHz to 5 GHz. Using optimized equivalent circuits obtained from HSPICE, mean and absolute deviation is calculated for each component of each device model. Monte Carlo Analysis for the capacitor structures is then performed using HSPICE. Using a comparison of the Monte Carlo results and measured data, it is determined that even a small number of sample structures, the statistical variation of the component values provides an accurate representation of the overall capacitor performance.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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• pp.330-333
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• 2000

With the recent development of the ultrahigh-speed optical time division multiplexed system, high-repetition rate optical-pulse stream generation is necessary. This is different from conventional approaches, which use fiber or integrated waveguide delay line circuits. The high-repetition-rate optical-pulse multiplication phenomenon occurs when the optical pulse's spectral width is greater than the transfer bandwidth of the coupler used. From the analysis, the output repetition rate can be controlled by using fiber couplers with different equivalent transfer bandwidths. The pulse seperation spacing is controlled by number of cascaded coupler in optical loop mirror coupler scheme.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(2)
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• pp.455-458
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• 2004

We present an efficient heuristic algorithm to reduce glitch power dissipation in combinational circuits. In this paper, the total number of glitches are reduced by replacing existing gates with functionally equivalent ones and by gate sizing which classified into three types and by buffer insertion which classified into two types. The proposed algorithm combines gate freezing, gate sizing. and buffer insertion into a single optimization process to maximize the glitch reduction. Our experimental results show an average of $67.8\%$ glitch reduction and $32.0\%$ power reduction by simultaneous gate freezing, gate sizing, and buffer insertion.

• 전기화학회지
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• 제3권2호
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• pp.76-80
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• 2000

Electrochemical oxidation of ethanol has been studied at nickel and $RuO_2-modified$ nickel electrodes in 1 M KOH using electrochemical impedance spectroscopy. Equivalent circuits have been worked out from simulation of impedance data to model oxidation of ethanol as well as the passivation of the electrode. The charge-transfer resistances for oxidation of these electrodes became smaller in the presence of ethanol than in its absence. The nickel substrate facilitated ethanol oxidation at $RuO_2-modified$ nickel electrodes. We also describe the Performance of nanosized electrocatalysts of the same composition in comparison to those of the bulk electrodes. The nanosized electrodes were obtained by electrode-positing the alloy from complexed form of these metal ions with fourth and fifth generation polyamidoamine dendrimers.

• 대한전기학회논문지
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• 제33권5호
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• pp.167-172
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• 1984

This paper describes the finite element analysis of magnetostatic field problems with permanent magnets. Two kinds of algorithms, one using the magnetic vector potential and the other using the magnetic scalar potential, are introduced. The magnetization of the pemanent magnet is used as the source instead of the magnetic equivalent current in both of the formulations using the magnetic vector potential and the magnetic scalar potential. A simple functional, which has only the region integral instead of the region integral and boundary integral, is derived in the formulation using the magnetic scalar potential. These make the formulation of the system equations simpler and more convenient than the conventional methods. The numerical results by the two proposed algorithms for a C-type permanent magnet model are compared with the analytic solutions respectively. The numerical results are in good agreement with the analytic solutions.