• 대한조선학회논문집
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• 제31권4호
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• pp.23-31
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• 1994

구획배치 모델은 구획의 경계면으로 사용되는 구조 부재요소들에 의해 정의되는 공간들의 특성 및 형상정보에 의해 표현된다. 이러한 구획배치 모델링 작업을 효율적으로 수행하기 위해 Chopping 및 Merging 모델링 기법을 이용한 그래픽 지원 대화식 구획배치 모델러를 개발하였다. 일반적으로 구획배치 모델링을 위해 사용되는 프로그램 내부 기법이 아무리 우수해도, 프로그램을 이용하는 사용자 입장에서 입력방식이 불편할 경우에는 프로그램 활용가치는 반감된다. 따라서 본 논문에서는 그래픽 사용자 인터페이스 기법을 이용하여 사용자가 편리하게 구획배치 모델링 작업을 수행할 수 있는 방법을 개발하고 이를 구현하였다. 본 연구를 통해 개발된 구획배치 모델링 방법은 솔리드 모델링 개념의 모델링 기법과 모델링을 위해 사용자가 입력해야 하는 정보를 그래픽 지원 인터페이스를 이용하여 신속하고 편리하게 처리할 수 있도록 함으로써, 효율적인 구획배치 모델링을 수행할 수 있도록 하였다. 본 연구를 통해 개발된 구획배치 모델러를 실선에 적용해 본 결과 보다 효율적이고 편리하게 구획배치 모델링을 수행할 수 있음을 확인하였으며, 실선에 적용한 예를 보였다.

• 한국초지조사료학회지
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• 제1권1호
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• pp.18-28
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• 1978

재료(材料)의 수확시기(收穫時期)와 여건(予乾), 세절(細切) 등(等)의 물리적(物理的)인 처리(處理)가 싸이레지품질(品質)에 미치는 영향(影響)을 구명(究明)하기 위해 Italian ryegrass(Lolium multi florum)는 출수전(出穗前) I)과 출수기(出穗期) II), 섬다비(Dystaenia takesimana NaKai)는 개화전(開花前) III)에 각각(各各) 예취(刈取)하여 무처리(無處理) A) 1일(日) 여건(予乾) B), $1{\sim}2cm$ 세절(細切) C), 세절후(細切後) 여건(予乾) D)의 4가지 조제방법(調製方法)으로 $1,727cm^3$의 프라스틱 원통 싸이로를 사용(使用)하여 싸이레지 조제후(調製後) 실온(室溫)에서 약(約) 3개월(個月) 저장(貯藏)한 후케 동시(同時)에 개봉(開封)하여 조사(調査)한 바 그 결과(結果)는 다음과 같다. 1. 섬바디는 조섬유함량(粗纖維含量)이 낮고 N.F.E/CP 비율(比率)이 6.31로 Italian ryegrass보다 싸이레지에 적합(適合)한 일반성분(一般成分)을 함유(含有)하고 있었다. 2. 무처리(無處理) 및 세절시(細切時) 일반성분(一般成分) 중(中) N.F.E 손실(損失)이 가장 많았고 여건시(予乾時)는 적었다. 3. 세절(細切), 여건(予乾)은 건물소화율(乾物消化率)을 개선(改善)시켰다. 4. 동일용적내(同一容積內)에 건물충전량(乾物充塡量)은 Italian ryegrass 출수전(出穗前)에 비(比)해 출수기(出穗期) 및 섬바디가 각각(各各) 8%, 69% 증가(增加)되었고, 여건(予乾) 또는 세절시(細切時) 무처리(無處理)보다 각각(各各) $41%{\sim}134%$ 증가(增加)되었다. 5. 저장중(貯藏中) 중량손실(重量損失)은 대부분(大部分)이 첫 주(週)에 발생(發生)되었고 손실(損失)은 4주(週)까지 서서히 계속되었다. 8주(週)까지의 최고손실(最高損失)은 무처리(無處理)의 3.76%였다. 6. 1일(日) 여건(予乾)으로 건물함량(乾物含量)은 $23%{\sim}131%$ 증가(增加) 시켰다. 여건(予乾), 세절(細切)은 pH, 유산함량(乳酸含量)은 유의(有意)하게 증가(增加)시켰으나 반대로 초산(醋酸), 낙산(酪酸) $NH_3-N$ 함량(含量) 유의(有意)하게 감소(減少)시키고 품질개선(品質改善)에 현저(顯著)한 결과(結果)가 인정(認定)되었다. 7. $NH_3-N$과 낙산(酪酸), 유산(乳酸)과 건물함량(乾物含量) 간(間)에는 각각(各各) r=0.782**, r=0.634**의 상관(相關)이 있었으며 회귀방정식(回歸方程式)은 각각(各各) y=12.853X+4.908(X=낙산함량(酪酸含量)), y=0.061X+1.309(X=건물함량(乾物含量))이었다. 8. 이상(以上)의 결과(結果) 양질(良質) 싸이레지 조제(調製)를 위(爲)해서 Italian ryegrass는 여건(予乾) 또는 세절(細切)이 반드시 필요(必要)하며, 섬바디는 여건(予乾), 세절(細切)이 품질개선(品質改善)에 유효(有效)하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2323-2328
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• 2011

There have been many changes in Subway train types since SeoulMetro opened the Line No.1 in 1974. Propulsion control device has changed many times following the generations of control method from resistance control method which uses large resistor for the traction motor control to chopping control which uses power semiconductors and finally to inverter control. Railroad vehicle propulsion control device refers to devices such as converter/inverter which supply power for subway operation, power conversion equipment like small switching-mode power supply and traction motor. In this paper, we will analyze every part of railroad vehicle propulsion control device of SeoulMetro so we can find problems in the subway operation. And we will present propulsion control device model which makes minimized failures, efficient maintenance possible when replacing railroad vehicle later. By doing this, we hope to ensure stability and improve energy efficiency to the top.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제15권4호
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• pp.283-288
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• 2015

In this paper, we propose a dynamic mathematical model of love involving various external forces, in order to analyze the chaotic phenomena in a love model based on Romeo and Juliet. In addition, we investigate the nonlinear phenomena in a love model with external forces using time series and phase portraits. In order to describe nonlinear phenomena precisely using time series and phase portraits, we vary the type of external force, using models such as a sine wave, chopping wave, and square wave. We also apply various different parameters in the Romeo and Juliet model to acquire chaotic dynamics.

• 한국자동차공학회논문집
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• 제7권9호
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• pp.97-104
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• 1999

Brake squeal noise has been a problem since the early days of motoring . It is important to obtain vibration mode shape for reduction of brake noise . Stroboscopic Electronic Speckle Pattern Interferometry is a very powerful measuring method for study of vibrating objects in static state compared with conventional methods because this method can give both resonance frequency and quantitative visualization of vibration mode shape at the same time. In this paper, we performed qualitative visualization and quantitative analysis of vibration mode shpae of disk brake by using stroboscopic ESPI and phase shifting method. The stroboscopic wavefronts are obtained by chopping continuous wave laser beam using acousto-optic modulator .Experiments were performed at the same constraint conditions as disk brake of the practical vehicle as far as possible. The experimental results of this paper show quantitative measurement of vibration mode shape and quantiative visualization of vibration amplitude of disk brake with 3D plotting.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.231-233
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• 1991

This paper discribes a study on the switching character of MOS-GTO and the design of gate drive circuit. Chopping power supply converter, synchronious and asyncronious motor speed adjustment, inverter, etc., needs low drive energy "high frequency" switches. To fulfill these need, switches must have rapid switching time and insulated gate control. MOS-GTO structure is well suited to these constraints. The power switch is serial installation of a GTO thyrister and a MOS Transistor. The gate of the GTO is linked to positive pole of the cascode structure via a MOS high voltage transistor and ground via a transient absorber diode. This high performance MOS-GTO assembly considerably increases the strength which facilitate the drive of GTO thyristers.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권6호
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• pp.291-297
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• 2003

This paper presents a current-source-inverter based on a buck-boost configuration and its application for residential photovoltaic system. The proposed circuit has five switches. Among them, only one switch acts as chopping, and the other determine the polarity of output; therefore, it can reduce the switching loss. Because the input inductor current is operated on the discontinuous conduction mode, high power factor can be achieved without additional input current controller. So the overall system shows a simple structure. The operational modes are analysed in depth, and then it was verified through the experimental results using a 150 [W] prototype equipped with digital signal processor TMS320F241.

• Applied Biological Chemistry
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• 제27권
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• pp.18-28
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• 1984

In order to improve feed values of Korean agricultural by-products, various treatments including physical, chemical, physicochemical and fermentation were suggested in th is review article. Physical treatments such as chopping, grinding and pelleting reduce partiole size of agricultural by-products, and increase passage rate from the rumen, thus may increase voluntary feed intake and weight gain. Digestibility and voluntary feed intake of straw, rice hull and sawdust, also, may be increased by chemical treatment using sodium hydroxide or ammonia. Especially, because nitrogen content of by-products increase and toxic problem is not posed by ammonia treatment, it's practical usage is recommended in Korea. Silage or fermentation treatment using principles of microbial fermentation may improve palatability of low quality by-products. As mentioned above, it is concluded that various treatments suggested are desirable and improve feed value but may raise several problems. Unfortunately, because cost for installation and products is great and processing work is complicate, farmers are not using well these processing methods until now. Therefore, in order to increase the practical usage at farm level, it is thought that many research works be achieved for efficient process which have simple operation and low installation cost.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.600-604
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• 1991

In this paper, an advanced PWM modulation strategy for driving a variable-speed induction motor is introduced. According to this method, the technique of efficiently eliminating harmonics component is achived. A switching pattern was computed making use of the near-proportionality of voltage and frequency in AC machines operating with constant flux. At low magnitudes and low frequencies of the foundamental, many more harmonics are eliminated than at high magnitudes and frequencies. In order to keep the inverter switching frequency constant over the output frequency range, chopping times diminishes as the frequency of the fundamental increases.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.611_612
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• 2009

This paper deals with dynamic analysis of linear switched reluctance motor considering electromagnetic characteristics. First, inductance profile of linear switched reluctance motor calculate at align and unalign position and phase resistance using analytical method. Analytical method of this paper used space harmonics method, also, analysis result compares with data that is derived through an finite element method, and proved validity. In dynamic simulation of linear switched reluctance, we analyzed dynamic characteristic of linear switched reluctance motor according to single pulse waveform and hard chopping voltage PWM.