• Title/Summary/Keyword: interferences

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평행기구 머니플레이터의 작업공간에 대한 연구

  • 정판규;이민기;최병오
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.765-768
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    • 1995
  • A double parallel manipulator has only two or three links in each parallel mechanism. this reduces link interferences so that we expect a large workspace. To prove this property, this paper analyzes the workspace of a double parallel manipulator and compare it with that of a Stewart Platform. the analysis is separately conducted in a positional and an orientational division. For each, we obtain the workspace accrding to the ranges of lengths of links and show the volume in a cartesian coordinate or the angular ranges in yaw and pitch motions.

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Parameter Estimation of Tissue Structure Characteristics in Ultrasound Measurement (초음파를 이용한 조직구조 특성변수의 측정)

  • 곽철은;김종원
    • Journal of Biomedical Engineering Research
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    • v.7 no.1
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    • pp.41-44
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    • 1986
  • The objective of tissue characterization is to provide quantitative information about the physical state of tissue interrogated by an ultrasound beam. In the computer simulation, it was found that the echoes were composed of the interferences of the ultrasonic waves reflected from both sides of the thin object, and could be separated by the spectral correlation method. Also, the phantom study demonstrates that thickness of the thin acryl layer beyond the resolution of common ultrasonic imaging systems can be measured- using this method.

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Effective Transmission Method for low power RF systems

  • Kim, Jung-Won;Choi, Ung-Se
    • Journal of IKEEE
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    • v.12 no.2
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    • pp.81-86
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    • 2008
  • In wireless communication system using 2.4GHz radio link, data rate varies with time due to interferences, which causes the performance degradation. Therefore, effective transmission methods are required to obtain better performance according to varying data rate. This paper proposes a novel method that increases the data rate, as well as the influence of different loop-filter bandwidths on the performance of the PLL. Experimental results show that the proposed method is effective because it can achieve higher throughput in various data rate.

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Improved Blind Multipath Estimation for Long Code DS-CDMA

  • Yu Qian;Bi Guoan;Zhang Gaonan
    • Journal of Communications and Networks
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    • v.7 no.3
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    • pp.278-283
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    • 2005
  • This paper proposes a blind channel estimation scheme for long code direct sequence code division multiple access (DS­CDMA) systems with multipath fading channels. This scheme combines the advantages of Toeplitz displacement and correlation matching methods to achieve improved performance. The basic idea is to remove the effects of noise and interferences with Toeplitz displacement operation and then estimate the multi path channel parameters with the correlation matching method. Simulation results are presented to show that the proposed scheme provides better MSE performance and robustness against the near-far problem.

Multipath Interference Cancellation Algorithm in WCDMA forward link (WCDMA 순방향 링크에서의 다중 경로 간섭 제거 알고리즘)

  • 유현규;권종형;류탁기;홍대식;강창언
    • Proceedings of the IEEK Conference
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    • 2001.06a
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    • pp.353-356
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    • 2001
  • In WCDMA systems, it is difficult to use high level modulation schemes in Rayleigh fading channel. Components of Multipath interference give signals much inteferences. Multipath interference cancellation is one of the method to overcome this problem. In this paper, multistage PIC algorithm is used to verify a performance of multipath interference cancellation. It is algorithm gradually canceling the multipath interferences as a stage number is increases. In computer simulations, it is verified that multipath interference cancelation is necessary and using its algorithm give much better performances than not using.

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2 Dimensional Modeling of Centerless Grinding -Interference Phenomena-

  • Kim, Kang
    • International Journal of Precision Engineering and Manufacturing
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    • v.4 no.4
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    • pp.32-38
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    • 2003
  • An analytical model of the interference phenomena in the centerless grinding process is developed to investigate their effects on the roundness profile of a centerless ground workpiece. In this work, the regulating wheel and work-rest blade interferences are modeled as a single point contact. The grinding wheel interference is modeled as multiple points contact because material removal is determined by the duration of contact. The computer simulation results show good agreement with the experimental data. From this work, the existence and effects of the interference phenomena in the centerless grinding process are found.

Some Interference Studies in Alkali and Alkali-Earth Metal Determination of Silicates by Atomic Absorption Spetrophotometry (원자흡광분석법에 의한 규산염중의 알칼리 및 알칼리토금속 정량시의 간섭에 대하여)

  • 박순자
    • Journal of the Korean Ceramic Society
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    • v.13 no.4
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    • pp.15-19
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    • 1976
  • Mutual interferences of alkali and alkali-earth metals in atomic absorption were examined. For determination of Na or K interfering elements increase the absorbancy, and for Ca or Mg decrease. Since influences of coexisting elements become nearly constant by addition of large amount of same coexisting element, could be use mixed standard solution for alkali or alkali-earth metal determination in the presence of other alkali and alkali-earth metals. The metals can be readily incorporated into scheme of rapid silicate analysis. Precision and accuracy are good.

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The Potential Interference of the Grounding Grids (격자형 접지전극의 전위간섭)

  • Lee, Bok-Hee;Lee, Tae-Hyung;Lee, Su-Bong;Jung, Hyun-Uk;Gil, Hyoung-Jun
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2005.11a
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    • pp.261-263
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    • 2005
  • This paper presents the potential interferences between various grounding electrodes. The ground potential rise and potential interference coefficient between grounding grid and ground rod were calculated. The potential rise and potential interference coefficient strongly depend on the distance between grounding electrodes.

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Design of the Electro-magnetic Compatibility(EMC) for Hybrid Electric Propulsion System (고전력 하이브리드 추진시스템의 전자파 적합성 설계 대책)

  • Lim, Jong-Kwang;Chang, Kyo-Gun
    • Journal of the Korea Institute of Military Science and Technology
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    • v.15 no.4
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    • pp.366-373
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    • 2012
  • In this paper, serious changes in the electromagnetic environment with increasing power and energy capabilities for electric driving and military mission are discussed. Design and control strategies on the Electro-Magnetic Compatibility(EMC) for the series hybrid electric vehicle are proposed to minimize the effects of electromagnetic interferences.

Determination of Trace Metals in Atmospheric Particulates by Ion Chromatography

  • Lee Yong-Keun;Kim Hak-Chul;Lee Dong Soo
    • Bulletin of the Korean Chemical Society
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    • v.15 no.12
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    • pp.1045-1049
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    • 1994
  • A simple and fast ion chromatographic method is developed for the determination of transition metals such as Fe, Cu, Ni, Zn and Co in atmospheric particulates. The method involves acid digestion, on-column preconcentration, and subsequent ion chromatogaphic detection. The precision of the method is less than 3${\%}$ RSD at parts per billion level for the metals studied. No significant interferences are observed. The results obtained with this method agree well with those by ICP-AES.