• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.532-533
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• 2010

This paper deals with the SCR thyristor switching characteristics of a 3-phase voltage disturbance generator. The series transformers of the generator require bypass SCR thyristors to provide the source voltage to the output terminal in normal operating mode. The SCR thyristor switching characteristics is quite different according to the connection point to the series transformer. The switching characteristics is analysed and verified through simulation results.

• 대한전기학회논문지
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• 제33권9호
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• pp.347-354
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• 1984

This paper presents a method of improving the power factor and , the waveform of A.C line currents and the output waveforms of AC to DC fully bridge converter systems which is achieved by connecting CON I.II and CON III.IV in series and parallel. The basic principle of the CON I.II.III.IV's operation is simple and feasibility of thease converter is proved by experiments. CON I and CON III are constructed of natural commutation, CON II and CON IV are constructed of forced commutation. The experimental results show that the power factor and waveform of the source currents and the output waveforms are improved by the method of connecting converter in series and parallel and driving it in I, II, III, IV quadrant.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 F
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• pp.1966-1968
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• 1998

This paper describes a gate drive circuit for series connected IGBTs in high voltage applications. The proposed control criterion of the gate circuit is to actively limit the voltages during switching transients, while minimizing switching transient and losses. In order to achieve the control criterion, an analog closed loop control scheme is adopted. The performance of gate drive circuit is examined experimentally by the series connection of three IGBTs with conventional snubber circuits. The experimental results show the voltage balancing by an active control under wide variation in loads and imbalance conditions.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 전력전자학술대회
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• pp.188-189
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• 2017

There has been a growing demand for power semiconductor switches equipped with high-voltage blocking capability of kV range and fast-switching characteristics of ns range in various plasma application. This paper investigates the application of SiC MOSFETs in the particular plasma application which requires the blocking voltage of 4.5kV and the switching transient time of less than 100ns. In order to meet the required blocking voltage, the series connection of multiple SiC MOSFETs is adopted in this paper. Also, snubber capacitors are employed to equalize the voltage sharing among the series connected SiC MOSFETs. The simulation and experimental result successfully verifies the application of SiC MOSFETs and snubber capacitors in the plasma application requiring high-voltage and fast-switching load dynamics.

• Kyungpook Mathematical Journal
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• 제59권2호
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• pp.301-314
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• 2019

The aim of this article is to make a connection between the Pascal distribution series and some subclasses of normalized analytic functions whose coefficients are probabilities of the Pascal distribution. For these functions, for linear combinations of these functions and their derivatives, for operators defined by convolution products, and for the Alexander-type integral operator, we find simple sufficient conditions such that these mapping belong to a general class of functions defined and studied by Goodman, Rønning, and Bharati et al.

• 전력전자학회논문지
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• 제18권4호
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• pp.322-332
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• 2013

Conventional single-phase series quasi Z-source voltage compensator can not compensate for voltage sag less than 50% that frequently occurs in the industrial field. In this study, single-phase series quasi Z-source voltage sag-swell compensator which can compensate the voltage variation of entire range is proposed. The proposed system is composed of two quasi Z-source AC-AC converters connected in series with output terminal stage. Voltage sag less than 50% could be compensated by the intersection switching control of the upper converter duty ratio and of the upper converter duty ratio. Also the compensation voltage and its flowchart for each compensation mode are presented for entire sag-swell region. To confirm the validity of the proposed system, a DSP(DSP28335) controlled experimental system was manufactured. As a result, the proposed system could compensate for the voltage sag/swell of 20% and 60%. Finally, voltage compensation factor and THD(Total Harmonic Distortion) according to voltage variation and load change were measured, and voltage quality shows a good results.

• Journal of Electrochemical Science and Technology
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• 제12권1호
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• pp.101-111
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• 2021

To improve the potential of single chamber microbial fuel cells (SCMFCs) as an applicable technology, the main challenge is a practical application for larger scales bioenergy production from potent exoelectrogenic microorganism with real dairy wastewater. To increase power generation, three individual MFCs were together operated in series best under the fed batch condition for 15 days. The volume of MFC 1 and MFC 2 is "300 mL" and MFC 3 is "500 mL" respectively. The individual MFCs 1, MFC 2 and MFC 3 gives an open circuit voltage of 0.60 V, 0.66 V and 0.55 V and result in total working voltage when connected in series of 1.745V, which lead an LED to glow. The maximum power densities obtained from MFC 1, MFC 2 and MFC 3 are 62 mW/㎡, 50 mW/㎡ and 45 mW/㎡ (normalized to the surface area of the anodic electrode, which was 50 ㎠ for all three MFCs), and corresponding to current densities of 141 mA/㎡, 155 mA/㎡ and 123 mA/㎡, respectively. Therefore this work suggests the cheapest way to connect microbial fuel cells in series to gain power with the lowest operating cost and chemical oxygen demand (COD) removal.

• Journal of Information Processing Systems
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• 제18권1호
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• pp.115-129
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• 2022

Adopting Internet of Things (IoT)-based technologies in smart homes helps users analyze home appliances electricity consumption for better overall cost monitoring. The IoT application like smart home system (SHS) could suffer from large missing values gaps due to several factors such as security attacks, sensor faults, or connection errors. In this paper, a novel framework has been proposed to predict large gaps of missing values from the SHS home appliances electricity consumption time-series datasets. The framework follows a series of steps to detect, predict and reconstruct the input time-series datasets of missing values. A hybrid convolutional neural network-long short term memory (CNN-LSTM) neural network used to forecast large missing values gaps. A comparative experiment has been conducted to evaluate the performance of hybrid CNN-LSTM with its single variant CNN and LSTM in forecasting missing values. The experimental results indicate a performance superiority of the CNN-LSTM model over the single CNN and LSTM neural networks.

• 멤브레인
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• 제18권4호
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• pp.294-305
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• 2008

본 연구는 공정모사를 통해서 막모듈 배열 및 연결과 막모듈 내에서 공급 잔류액의 온도 변화가 투과증발 공정에 끼치는 영향을 관찰하였으며 이를 위해서 기본 막모듈이 직렬 혹은 병렬로 연결되어 있는 모듈들의 조합을 통한 투과탈수공정을 예측할 수 있는 모델식들을 확립하였다. 에탄올/물 혼합물을 모델 혼합물로 사용하였고 모델식들에 포함되어 있는 투과 파라메타들을 직접 실험에 의해 구하여 사용함으로써 모사의 현실성을 높였다. 모사를 통해서 모듈의 배열방식, 모듈 단의 갯수와 단사이의 공급액의 재가열등의 중요성을 검토하였다.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제26권1호
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• pp.1-13
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• 2023

수학과 목표인 창의적인 문제해결능력을 갖춘 인재를 양성하기 위해서 2009 개정 교육과정에서부터 수학교과를 통해 창의적이고 융합적인 사고를 신장할 것을 강조하여 왔다. 본 연구는 새롭게 개발되어 활용 중인 검정교과서에서 나타나는 창의·융합 역량이 어떻게 나타나는지 살펴보기 위해서 천재교과서(박)과 아이스크림을 선택하여 창의·융합의 하위요소에 따라서 분석하였다. 또한, 국정에서 검정으로 변화를 살펴보기 위해 2015 개정에 따른 국정 교과서도 함께 같은 분석 준거를 활용하여 분석하였다. 분석 결과, 세부적인 비율에 차이는 있지만, 공통적으로 세 가지 교과용 도서에서 창의성 중 유창성이 높은 비율로 나타났고, 융합은 외적 연결성이 높게 나타났다. 본 연구의 결과를 바탕으로 교과서 개발과 실행 과정에 대한 논의점을 제시하고자 한다.