• 한국지진공학회논문집
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• 제16권1호
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• pp.47-59
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• 2012

본 연구에서는 학교건물에서 나타나는 전형적인 조적조 채움벽 골조의 내진성능을 등가 스트럿 모델을 통해 평가하였다. 순수골조모델, 중심스트럿모델 및 편심스트럿모델의 세 가지 모형화 방법을 채택하였고, 문헌상으로 얻을 수 있는 범위의 스트럿 강성과 강도를 적용하여 거동특성의 차이를 분석하였다. 역량스펙트럼에 의해 산정된 성능점에서의 변위 및 손상정도에 큰 차이가 나타났으며, 채움벽은 순수골조모델과 비교할 때 중심스트럿모델에서는 유리하게, 편심스트럿모델에서는 불리하게 작용하는 것으로 나타났다. 최종극한변위에서의 거동 또한 모형화 방법 및 재료 속성에 따라서 최대강도, 층간변위, 파괴된 부재 수 및 위치 등에 큰 차이가 나타났다.

• Journal of Power Electronics
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• 제13권3호
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• pp.429-436
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• 2013

Online simulations are utilized to reduce time and cost in the development and performance optimization of plug-in hybrid electric vehicle (PHEV) and electric vehicles (EV) systems. One of the most important factors in an online simulation is the accuracy of the model. In particular, a model of a battery should accurately reflect the properties of an actual battery. However, precise dynamic modeling of high-capacity battery systems, which significantly affects the performance of a PHEV, is difficult because of its nonlinear electrochemical characteristics. In this study, a dynamic model of a high-capacity battery cell for a PHEV is developed through the extraction of the equivalent impedance parameters using electrochemical impedance spectroscopy (EIS). Based on the extracted parameters, a battery cell model is implemented using MATLAB/Simulink, and charging/discharging profiles are executed for comparative verification. Based on the obtained results, the model is optimized for a high-capacity battery cell for a PHEV. The simulation results show good agreement with the experimental results, thereby validating the developed model and verifying its accuracy.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권3호
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• pp.356-364
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• 2015

The transmission performance of TSV considering the effect of electronic-thermal coupling is an new challenge in three dimension integrated circuit. This paper presents the thermal equivalent circuit (TEC) model of the TSV, and discussed the thermal equivalent parameters for TSV. Si layer is equivalent to transmission line according to its thermal characteristic. Thermal transient response (TTR) of TSV considering electronic-thermal coupling effects are proposed, iteration flow electronic-thermal coupling for TSV is analyzed. Furthermore, the influences of TTR are investigated with the non-coupling and considering coupling for TSV. Finally, the relationship among temperature, thickness of $SiO_2$, radius of via and frequency of excitation source are addressed, which are verified by the simulation.

• ETRI Journal
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• 제27권5호
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• pp.628-634
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• 2005

From AC analysis results utilizing a 2-dimensional device simulator, we extracted an AC-equivalent circuit of a grounded-gate NMOS (ggNMOS) electrostatic discharge (ESD) protection device. The extracted equivalent circuit is utilized to analyze the effects of the parasitics in a ggNMOS protection device on the characteristics of a low noise amplifier (LNA). We have shown that the effects of the parasitics can appear exaggerated for an impedance matching aspect and that the noise contribution of the parasitic resistances cannot be counted if the ggNMOS protection device is modeled by a single capacitor, as in prior publications. We have confirmed that the major changes in the characteristics of an LNA when connecting an NMOS protection device at the input are reduction of the power gain and degradation of the noise performance. We have also shown that the performance degradation worsens as the substrate resistance is reduced, which could not be detected if a single capacitor model is used.

• 한국자동차공학회논문집
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• 제16권5호
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• pp.100-105
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• 2008

In the design process of an automobile part, several analysis methods are usually utilized to evaluate the performance of the part. However, most automobile design engineers do not directly utilize CAE (Computer Aided Engineering) tools since specific skills are required to obtain practical results. Moreover, CAE requires a huge amount of computation time and cost. In order to resolve these problems, a new design approach named First Order Analysis (FOA) technique has been proposed. In this paper, the FOA technique is employed to design a vehicle sub-frame. An equivalent model of the vehicle sub-frame which only consists of beam elements is proposed and the modal properties obtained with the model are compared to those obtained with a full scale finite element model. The effect of some parameter tolerances on the modal characteristics of the vehicle sub-frame is investigated by employing the FOA equivalent model.

• Journal of information and communication convergence engineering
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• 제4권4호
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• pp.151-154
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• 2006

In this work, a novel optimal multiuser detection (MUD) approach, which not only achieves the optimal maximum-likelihood (ML)-like performance but also has reasonably low computational complexity, for Space-time coded OFDM (ST-OFDM) systems is presented. In the proposed detection scheme, the signal model is firstly re-expressed into linearly equivalent one. Then, with the linearly equivalent signal model, a new jointly MUD algorithm is proposed to detect signals. The ML-like bit-error-rate (BER) performance and reasonably low complexity of the proposed detection are verified by computer simulations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.149-151
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• 2006

This paper shows the characteristic analysis of single-phase LSPM(Line Start Permanent Magnet) synchronous motor considering overhang structure. To obtain the dynamic and steady performance of the motor, the D-Q equivalent circuit is used and the circuit parameters are extracted by 3D FEM. The performance of the model with overhang is compared with conventional model without overhang on the condition that both models have the same volume of the permanent magnet.

• 대한의용생체공학회:의공학회지
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• 제2권1호
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• pp.31-38
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• 1981

The objective of the present study was to develop an equivalent circuit model of glucose kinetics including the hepatic glucose balance functions which were neglected in the previous compartmental models. Using this circuit model, the insulin resistivity parameter and hepatic glucose sensitivity parameter were estimated in optimal fitting of the model based data of glucose and insulin concentration to the reported clinical intravenous glucose tolerance test(IVGTT) data in normal and diabetic subjects. The addition of the hepatic function in the model has improved the overall performance of the simulation. Also, the computed tissue insulin resistivity and the hepatic glucose sensitivity are shown to be significant in distinguishin four clinical groups of normal and diabetic groups.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권5호
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• pp.463-469
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• 2015

A vibration-based energy harvester and its equivalent circuit models have been reported. Most models predict voltage signals at harmonic excitation. However, vibrations in a natural environment are unpredictable in frequency and amplitude. In this paper, we propose a realistic equivalent circuit model of a frequency-up-converting impact-based piezoelectric energy harvester. It can describe the behavior of the harvester in a real environment where the frequency and the amplitude of the excitation vary arbitrarily. The simulation results of the model were compared with experimental data and showed good agreement. The proposed model can predict both the impact response and long term response in a non-harmonic excitation. The model is also very useful to analyze the performance of energy conversion circuitry with the harvester.

• Journal of Power Electronics
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• 제16권1호
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• pp.374-387
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• 2016

This paper derives an improved analytical model to estimate switching loss and analyze the effects of parasitic elements on the switching performance of SiC MOSFETs. The proposed analytical model considers the parasitic inductances, the nonlinearity of the junction capacitances and the nonlinearity of the trans-conductance. The turn-on process and the turn-off process are illustrated in detail, and equivalent circuits are derived and solved for each switching transition. The proposed analytical model is more accurate and matches better with experimental results than other analytical models. Note that switching losses calculated based on experiments are imprecise, because the energy of the junction capacitances is not properly disposed. Finally, the proposed analytical model is utilized to account for the effects of parasitic elements on the switching performance of a SiC MOSFET, and the circuit design rules for high frequency circuits are given.