• 제목/요약/키워드: Reduction Techniques

검색결과 1,584건 처리시간 0.033초

RPWM 기법을 이용한 능동클램프 ZVS 플라이백 컨버터 전도노이즈저감 (Conducted Noise Reduction in Active clamp ZVS flyback converter using Random Pulse Width Modulation)

  • 김영규;최태영;원충연;김재문;김규식;최세완
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2002년도 전력전자학술대회 논문집
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    • pp.498-501
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    • 2002
  • In the conventional PWM converter, high-frequency switching techniques was used for high-density of energy, but occurred a lot of problems such as switching losses, switching voltage/current stresses, EMI(Electromgnetic Interference) and so on. To overcome these problems, various soft switching techniques have been presented. However these techniques are focused on reducing switching losses and voltage/current stresses . The simulation and experimental results are shown that the active clamp ZVS flyback converter with the proposed RPWM(Random Pulse Width Modulation) technique reduces the conducted noise.

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직파재배 벼의 영농기법 및 비용 절감 효과 - 현장 사례 연구(관개배수 \circled1) (Cropping techniques and cost reduction of direct seeded rice - A case study)

  • 정상옥;김지용;안태홍
    • 한국농공학회:학술대회논문집
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    • 한국농공학회 2000년도 학술발표회 발표논문집
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    • pp.144-150
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    • 2000
  • A field case study was performed to investigate optimum cropping technique of direct seeded rice. In addition, an economic analysis was made to see the effect of this method. Field study was performed at a 2.1㏊ paddy field in Kimjae city, Chonbuk province from 1991 to 1999. Various direct seeding method such as dryland seeding, wetland seeding, and no-till wetland seeding were introduced. Optimum cropping techniques such as when and how to manage the rotary till, water supply, herbicide application, and ponding depth were developed for different cropping methods. Based on this study ₩640,000 per ㏊ can be saved by direct seeding due to no nursery cost, and ₩l,220,000 per ㏊ can be saved by no-till and no nursery cost. With further study these cropping techniques including the no-till direct deeding proves to be advantageous these can be adopted for the most of the paddy fields in Korea.

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An Efficient Low Complexity Blind Equalization Using Micro-Genetic Algorithm

  • Kim, Sung-Soo;Kang, Jee-Hye
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • 제4권3호
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    • pp.283-287
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    • 2004
  • In this paper, a method of designing the efficient batch blind equalization with low complexity using a micro genetic algorithm (GA), is presented. In general, the blind equalization techniques that are focused on the complexity reduction might be carried out with minor effect on the performance. Among the advanced various subjects in the field of GAs, a micro genetic algorithm is employed to identity the unknown channel impulse response in order to reduce the search space effectively. A new cost function with respect to the constant modulus criterion is suggested considering its relation to the Wiener criterion. We provide simulation results to show the superiority of the proposed techniques compared to other existing techniques.

Classification and Comparison of EMI Mitigation Techniques in Switching Power Converters - A Review

  • Yazdani, Mohammad Rouhollah;Farzanehfard, Hosein;Faiz, Jawad
    • Journal of Power Electronics
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    • 제11권5호
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    • pp.767-777
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    • 2011
  • Power electronic systems such as switching power supplies are accounted as noise sources for other sensitive circuits. EMI caused by power converters can disturb the normal operation of the converter and other adjacent systems. Major research is concentrated on EMI mitigation for power converters in which the main concern is compliance with EMC standards to ensure proper operation of converters and nearby systems. This paper reviews EMI reduction techniques related to switching power converters with emphasis on the conducted EMI. A comprehensive review of significant research works is performed and various methods are thoroughly discussed and compared. Also, a classification of methods is presented. Moreover, converter prototypes are realized which contain several EMI mitigation techniques and their effects are presented via experimental results.

여러 가지 컴퓨터 메모리 참조 방법과 자료구조에 대한 단체법 프로그램 수행 속도의 비교 (Experimental Comparisons of Simplex Method Program's Speed with Various Memory Referencing Techniques and Data Structures)

  • 박찬규;임성묵;김우제;박순달
    • 산업공학
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    • 제11권2호
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    • pp.149-157
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    • 1998
  • In this paper, various techniques considering the characteristics of computer memory management are suggested, which can be used in the implementation of simplex method. First, reduction technique of indirect addressing, redundant references of memory, and scatter/gather technique are implemented, and the effectiveness of the techniques is shown. Loop-unrolling technique, which exploits the arithmetic operation mechanism of computer, is also implemented. Second, a subroutine frequently called is written in low-level language, and the effectiveness is proved by experimental results. Third, row-column linked list and Gustavson's data structure are compared as the data structure for the large sparse matrix in LU form. Last, buffering technique and memory-mapped file which can be used in reading large data file are implemented and the effectiveness is shown.

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클린룸의 에너지 절약 기술 개발과 신뢰성 향상의 필요성에 관한 연구 (A Study on the Necessity for Energy Saving Techniques and Improvement of Dependability of Clean room)

  • 김종걸;김형만;김영섭;고재규;최성원;조국형
    • 대한안전경영과학회:학술대회논문집
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    • 대한안전경영과학회 2008년도 추계학술대회
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    • pp.641-647
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    • 2008
  • Since korea must get 5.2% reduction of green gas emission and insecurity of economic impact is on the increase due to unstable oil market, the demands of energy saving techniques are increasing. In this paper, we investigate necessity of development of enormous energy used cleanroom energy saving techniques furthermore we also investigate the adoption of dependability management system to develop the energy saving cleanroom development process.

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Peak-to-Average Power Ratio (PAPR) Reduction Techniques of OFDM Signals

  • Lee, Byung-Moo
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2008년도 하계종합학술대회
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    • pp.7-8
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    • 2008
  • It is well-known that one of the most serious problems of Orthogonal Frequency Divison Multiplexing (OFDM) is its high Peak-to-Average Power Ratio (PAPR) which seriously limits the power efficiency of High Power Amplifier (HPA). This paper introduces various methodologies to cope with this problem.

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