• 지구물리와물리탐사
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• 제14권3호
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• pp.185-190
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• 2011

해양전자탐사의 모델링에서 1차장은 송수신 간격이 넓어지면 크게 감소하기 때문에 기존의 선형필터로서는 정확한 계산이 어려워진다. 그러나 균질 반무한공간의 경우 TM 모드의 Hankel 변환에는 해석해가 존재하므로 이를 이용하면 Hankel 변환의 계산을 위한 선형필터의 정확도를 검토할 수 있다. 그 결과 송수신 간격이 커짐에 따라서 전자기장이 반대수 그래프에서 선형적으로 감소하는 경우는 총 36가지 송수신 조합 중 9가지 뿐이며, 나머지 조합에서는 전자기장이 0 이거나 아니면 공기층의 영향을 받아 전자기장의 감소가 크지 않다. 다행히 이 9가지 조합에는 해석해가 존재하고, 나머지 조합에서는 전자기장의 극단적인 감소가 나타나지 않으므로 비교적 길이가 짧은 필터로도 Hankel 변환의 정확한 계산이 가능하다. 이상의 결과를 토대로 이 논문에서는 균질 반무한공간 모델에 대한 전자기장 계산법으로서 TM 모드의 Hankel 변환에는 해석해를 쓰고 TE 모드 계산에는 그 계수가 61개인 필터를 쓰는 방식을 제안한다.

• 한국대기환경학회지
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• 제25권1호
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• pp.75-89
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• 2009

The purpose of this study was to identify $PM_{2.5}$ sources and to estimate their contributions to the border of Yongin-Suwon area, based on the analysis of the $PM_{2.5}$ mass concentration and the associated inorganic elements, ions and carbon components. The contribution of $PM_{2.5}$ sources were estimated by using a positive matrix factorization (PMF) model to identify air emission sources. For this study, $PM_{2.5}$ samples were collected from May, 2007 to April, 2008. The inorganic elements were analyzed by an ICP-AES. The ionic components in $PM_{2.5}$ were analyzed by an Ie. The carbon components were also analyzed by DRI/OGC analyzer. After performing PMF modeling, a total of 12 sources were identified and their contributions were quantitatively estimated. The contributions from each emission source were as follows: 11.3% from oil combustion source, 3.4% from bus/highway source, 5.8% from diesel vehicle source, 4.7% from gasoline vehicle source, 8.8% from biomass burning source, 15.1 % from secondary sulfate, 5.2% from secondary nitrate source, 13.4% from industrial related source, 4.1% from Cl-rich source, 19.6% from soil related source, 1.0% from aged sea salt, and 7.4% from coal combustion source, respectively. This study provides basic information on the major sources affecting air quality, and then it will help to effectively control $PM_{2.5}$ in this study area.

• JSTS:Journal of Semiconductor Technology and Science
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• 제12권2호
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• pp.230-239
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• 2012

In this paper, we present the radio-frequency (RF) modeling for gate-all-around (GAA) junctionless (JL) MOSFETs with 30-nm channel length. The presented non-quasi-static (NQS) model has included the gate-bias-dependent components of the source and drain (S/D) resistances. RF characteristics of GAA junctionless MOSFETs have been obtained by 3-dimensional (3D) device simulation up to 1 THz. The modeling results were verified under bias conditions of linear region (VGS = 1 V, VDS = 0.5 V) and saturation region (VGS = VDS = 1 V). Under these conditions, the root-mean-square (RMS) modeling error of $Y_{22}$-parameters was calculated to be below 2.4%, which was reduced from a previous NQS modeling error of 10.2%.

• 한국수소및신에너지학회논문집
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• 제17권3호
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• pp.338-346
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• 2006

In this paper, the test results of medium-size(120 kW class) PV system which was installed in the Taeahn thermal power station of Korea Western Power Co., Ltd., were summarized for developing the practical technology to applicate high voltage grid connection PV system. The 120 kW photovoltaic system which was consisted of 1,300 modules, PCS, and 150 kVA transformer station has been operated since Aug. 05, 2005. For verifying the modeling results of PV system, the operation data was compared with modeling results which was executed commercial PSCAD/EMTD and Psim tools. An equivalent circuit model of a solar cell has been also used for solar array modeling. A series of parameters required for array modeling have been estimated from general specification data of a solar module. A PWM voltage source inverter(VIS) and its current control scheme have been analyzed by using P&O (perturbation and Observation) MPPT algorithms technique.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.205-215
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• 2015

Common mode (CM) conducted interference are predicted and compared with experiments in a motor drive system of Electric vehicles in this study. The prediction model considers each part as an equivalent circuit model which is represented by lumped parameters and proposes the parameter extraction method. For the modeling of the inverter, a concentrated and equivalent method is used to process synthetically the CM interference source and the stray capacitance. For the parameter extraction in the power line model, a computation method that combines analytical method and finite element method is used. The modeling of the motor is based on measured date of the impedance and vector fitting technique. It is shown that the parasitic currents and interference voltage in the system can be simulated in the different parts of the prediction model in the conducted frequency range (150 kHz-30 MHz). Experiments have successfully confirmed that the approach is effective.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1184-1189
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• 2004

Coking process is the thermal decomposition of bituminous coal with final temperature of about $900^{\circ}C$ Because coke plays important roles in ironmaking process in a blast furnace it's essential for developing modeling of coke oven. In this study, An unsteady 2-dimesional model is proposed to simulate coking process in a coke oven. In this model, gas and solid phase are assumed homogeneous continnum and solid bed is assumed as porous media . The model contains governing equations for the solid phase and the gas phase. Complicated phenomena such as swelling, softening, resolidification and shrinkage are neglected and mass loss by drying and devolatilization is reflected by generation of internal pores. Drying, devolatilization, heat transfer and generation of internal pores are also reflected in source terms. Calulated results are compared with experimental data

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.127-131
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• 2005

The paper addresses modeling and analysis of a grid-connected photovoltaic generation system (PV system). PSCAD/EMIDC. an industry standard simulation tool for studying the transient behavior of electric power system and apparatus. is used to conduct all aspects of model implementation and to carry out extensive simulation study. An equivalent circuit model of a solar cell has been used for modeling solar array. A PWM voltage source inverter (VSI) and its current control scheme have been implemented. A maximum power point tracking (MPPT) technique is employed for drawing the maximum available energy from the PV array. Comprehensive simulation results are presented to examine PV array behaviors and PV system control performance in response to irradiation changes. In addition, dynamic responses of PV array and system to network fault conditions are simulated and analysed

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.85-86
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• 2011

In this paper, the virtual power grid of Jeju in 2020 is modelled including not only VSC HVDC(Voltage Source Current-High Voltage Direct Current) but also wind power generators as 200MW for onshore and 500MW for offshore by PSCAD/EMTDC. Each active power and reactive power are able to controlled by the VSC HVDC. In addition, to verify the characteristic of the modeling VSC HVDC, those wind power generators are cut off from the grid. The result show that the modeling power grid of Jeju become stabilized after 0.1second from failure.

• Transactions on Electrical and Electronic Materials
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• 제14권6호
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• pp.283-290
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• 2013

This paper illustrates the possibilities of using the program ATP-Draw (Alternative Transient Program) for the modeling of power networks to study power quality problems with highly detailed analyses. The Program ATP-Draw is one of the most widespread and oldest programs. A unique characteristic of this program is its public domain and the existence of forums and study committees where new application cases and modification are presented and shared publicly. In this paper, to study the propagation of harmonics through a power network, a part of an industrial power network was modeled. The network contains different types of electric components, such as transformers, transmission lines, cables and loads, and there is a source of harmonics that injects $3^{rd}$, $5^{th}$, $7^{th}$, $9^{th}$ and $11^{th}$ harmonic currents into the network, causing a distortion of the wave form of the currents and voltages through the power network.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.519-520
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• 2006

In this paper, to evaluate the grid-connected 120kW class Photovoltaic(PV) system performance, as a consisted of solar cells, PCS, 150kVA transformer station. The paper address modeling and analysis of a grid-connected 120kW class photovoltaic generation system(PV system) PSCAD/EMTD and Psim. A PWM voltage source inverter(VIS) and its current control scheme have been implemented. A P&O(Perturbation and Observation) MPPT algorithms technique modeling has been simulated and analysed.