• Title/Summary/Keyword: Function Analysis Phase

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The Identification of Generation Mechanism of Noise and Vibrtaion and Transmission Characteristics for Engine System - The Source Identification and Noise Reduction of Compartment by Multidimensional Spectral Analysis and Vector Synthesis Method - (엔진의 소음.진동발생기구 및 전달특성 규명 -다차원해석법과 벡터합성법에 의한 차실소음원 규명 및 소음저감 -)

  • O, Jae-Eung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.7
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    • pp.1127-1140
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    • 1997
  • With the study for identifying the transmission characteristics of vibration and noise generated by operating engine system of a vehicle, recently many engineers have studied actively the reduction of vibration and noise inducing uncomfortableness to the passenger. In this study, output noise was analyzed by multi-dimensional spectral analysis and vector synthesis method. The multi-dimensional analysis method is very effective in case of identification of primary source, but this method has little effect on suggestion for interior noised reduction. For compensation of this, vector synthesis method was used to obtain effective method for interior noise reduction, after identifying primary source for output noise. In this paper, partial coherence function of each input was calculated to know which input was most coherent to output noise, then with simulation of changes for input magnitude and phase by vector synthesis diagram, the trends of synthesized output vector was obtained. As a result, the change of synthesized output vector could be estimated.

Utility of Gait Analysis and Functional Assessment of Prosthetic Reconstruction in Bone Tumor around the Knee (슬관절 주위에 발생한 골종양 환자에서 종양 대치물을 이용한 재건술 후 기능적 평가 및 보행 분석의 유용성)

  • Lee, Jin-Ho;Seol, Young-Jun;Jung, Sung-Taek
    • The Journal of the Korean bone and joint tumor society
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    • v.18 no.2
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    • pp.51-58
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    • 2012
  • Purpose: This study attempts to know functional results and gait analysis usefulness in patients with bone tumor around knee joint tumors who underwent prosthesis knee joint reconstruction. Materials and Methods: Retrospective study was conducted with 7 patients out of 30 patients who underwent prosthesis knee joint reconstruction after wide marginal excision for bone tumor around knee in orthopedics of this hospital from 2001 to 2010. Functional assessment and gait analysis were perforemed. Results: For the SF-36 score, while 'role physical' and 'role emotional' items showed 100% (100 points) high scores individually, general health, physical function, vitality, and social function showed low scores. The mean score of MSTS was 88.1% (23.8 points [17-27]), indicating a relatively high score. For the gait analysis, mean gait velocity was 97.2 m/s, mean cadence was 105.6 step/min, mean stride length was 111.3 m, mean step length was 61.5 cm, swing phase was 39.8%cycle, stance phase was 60.1%cycle, mean single limb support was 37.1%cycle, mean double limb support was 13.0%cycle, and mean push off was 60.7%cycle. Conclusion: It is expected that prosthesis reconstruction after wide marginal excision for bone tumor around knee has relatively good functional results. Gait analysis was considered one of method which showed gait phase and assessed functional ability objectively by quantitative assessment post operative patient condition. It might help treatment and post operative rehabilitation planning with the functional assessment.

Coupled Analysis of Heat Transfer and Thermoelastoplastic deformation (열전달과 열탄소성변형의 연결해석)

  • 이용기;한흥남;오규환;이동녕
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1994.03a
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    • pp.47-54
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    • 1994
  • The study is concerned with the coupled analysis of heat transfer and thermoelastoplastic deformation. The thermoelastoplastic model is very useful for the analysis of residual stress and the analysis of thermal stress as well as the analysis of metal forming. Heat of deformation, phase transformation and contact heat transfer boundary are considered. The contact heat transfer boundary is treated by the interpolation of shape function. The analysis of deformation and the analysis of heat transfer are carried out for the could upsetting and the hot rolling. The computed results are found to be in good agreement with the experimental results.

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Performance Comparison of Phase Detectors for the Synchronization Analysis of Electroencephalographic Signal (뇌파신호의 동기해석을 위한 위상검출기의 성능비교)

  • Kim, HyeJin;Lee, JeeEun;Yoo, Sun K.
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.12
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    • pp.277-284
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    • 2013
  • The analysis of phase synchronization characteristics from EEG signals is important for the understanding of information processing functionality in the brain network. In this paper, wavelet transformation(WT), Hilbert tansformation (HT), complex demodulation (CD) methods having time localization characteristics were applied to real evoked potential data and noise added simulation data with center frequencies corresponding to EEG bands for the estimation performance analysis of phase offset, phase changing point, and interband crosstalk. The WT is the best both in ${\delta}$, ${\theta}$, and ${\alpha}$ band signal decomposition, and in analyzing phase synchronization performance. The CD can be efficiently used in changing point detection under tolerant noise condition because of its abrupt performance degradation over noise endurance level. From experimental observations, the WT is the most suitable in phase synchronization application of EEG signal, and the CD can be affordable in restricted application such as changing point detection for higher bands than ${\delta}$. Particularly, WT and CD can be used to detect the changing instant of brain function by indirectly estimating the phase changing point.

Spectral Analysis of DC Link Ripple Currents in Three-Phase AC/DC/AC PWM Converters (3상 AC/DC/AC PWM 컨버터의 직류링크 리플전류의 주파수 영역 해석)

  • 이동춘;박영욱;석줄기
    • The Transactions of the Korean Institute of Power Electronics
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    • v.7 no.3
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    • pp.244-252
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    • 2002
  • In this paper, do link ripple currents for three-phase ac/dc/ac PWM converters feeding adjustable speed ac machine drives are analysed in a frequency domain. The expression of the harmonic currents is developed by using switching functions of the converter and exponential courier series expansion. The effect of the displacement angle between the switching Periods of line-side converters and motor-side inverters on the dc link ripple currents is Investigated. Also, the influence of asynchronization of PWM is observed. The result of analysis is compared with frequency spectrum which results from PSIM simulation. The proposed analysis technique is useful to understand the principles of P% and to derive an equivalent model of the dc link capacitors in a high frequency range.

Error Analysis of Modernized GPS and Galileo Positioning (현대화된 GPS와 Galileo를 이용한 위치 결정에서의 오차해석)

  • Hwang Dong-Hwan;Lee Sang Jeong;Park Chansik
    • Journal of Institute of Control, Robotics and Systems
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    • v.11 no.7
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    • pp.644-650
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    • 2005
  • The expected positioning accuracies of civil users utilizing modernized GPS and Galileo are derived using the error analysis in this paper. Since, in general, the performance of DLL, PLL and FLL is proportional to chip lengths and wavelengths, the positioning accuracies from various measurements of modernized GPS and Galileo are derived as function of chip length and wavelength. These results are compared with that from GPS Ll measurement. In absolute positioning, compared to GPS C/A code only case, more than 17 times performance improvement is expected when all civil code signals of modernized GPS and Galileo (L1, L2, L5, E1, E5A and E5B) are used. In relative positioning, compared to GPS L1 carrier phase only case, more than 2 times performance improvement is expected when all civil signals of modernized GPS and Calileo are used. Furthermore, the relationship between GDOP and RGDOP in single frequency case is expanded to general case where multiple frequencies and both code and carrier phase measurements are used.

Characterization of Methanol-Water and Acetonitrile-Water Mixtures Using Iterative Target Transform Factor Analysis on Near Infrared Absorption Spectra (근적외선흡광스픽트럼에 대한 반복목표변환인자분석에 의한 메탄올-물 혼합액 및 아세토니트릴 -물 혼합액의 특성 확인)

  • 박영주;조정환
    • YAKHAK HOEJI
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    • v.48 no.1
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    • pp.6-12
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    • 2004
  • Near-infrared spectra of methanol-water mixtures and acetonitrile-water mixtures were acquired to find interactions between solvents widely used for reverse-phase liquid chromatography. Mixtures were prepared to give a series of increasing mole fractions of methanol or acetonitrile in water. Data matrices of acquired spectra were analyzed to determine the proper number of principal components of each mixture system using Malinowski's factor indicator function. Initial guess of score matrix and loading matrix were calculated by nonlinear iterative partial least squares (NIPALS) algorithm for faster computation. Iterative target transform factor analysis (ITTFA) was applied to convert the initial estimation of score matrix to true concentration profile and loading matrix to pure spectra of pure components of the mixtures. In case of methanol-water the number of principal components was found to be 4 and those initial guess of factors were converted to the pure spectra of water methanol and two kinds of complexes. In case of acetonitrile-water the number of pure components of the mixtures was found to be 3 and the pure spectrum of acetonitrile-water complex was found. The nonlinear characteristics of concentration profiles of complexes in the solvent mixtures may give a good criteria in understanding their elution characteristics in reverse-phase liquid chromatogrsphy.

ASYMPTOTIC ANALYSIS OF THE LOSS PROBABILITY IN THE GI/PH/1/K QUEUE

  • Kim Jeong-Sim
    • Journal of applied mathematics & informatics
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    • v.22 no.1_2
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    • pp.273-283
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    • 2006
  • We obtain an asymptotic behavior of the loss probability for the GI/PH/1/K queue as K tends to infinity when the traffic intensity p is strictly less than one. It is shown that the loss probability tends to 0 at a geometric rate and that the decay rate is related to the matrix generating function describing the service completions during an interarrival time.

Unbalance Response Analysis of Induction Motor Rotor Considering Unbalanced Electromagnetic Forces (불평형 전자기력을 고려한 유도전동기 회전자의 불평형 응답해석)

  • 손병구
    • Journal of Advanced Marine Engineering and Technology
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    • v.23 no.2
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    • pp.201-209
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    • 1999
  • This paper presents a general analytical method for analyzing mechanical unbalance response of unbalanced electromagnetic forces produced in induction motors with an eccentric rotor and a phase unbalance. The equations to be solved are a set of second order differential equations which give matrices with periodic coefficients that are a function of time due to the unbalanced electro-magnetic force. Unbalance response is processed by Newmark $\beta$ method. Two examples are given including an industrial application. The results show that the method proposed is satisfactory.

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BER Analysis of Coherent Free Space Optical Systems with BPSK over Gamma-Gamma Channels

  • Lim, Wansu
    • Journal of the Optical Society of Korea
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    • v.19 no.3
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    • pp.237-240
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    • 2015
  • We derived the average bit error rate (BER) of coherent free-space optical (FSO) systems with digital binary phase shift keying (BPSK) modulations over atmospheric turbulence channels with a gamma-gamma distribution. To obtain a generalized derivation in a closed-form expression, we used special integrals and transformations of the Meijer G function. Furthermore, we numerically analyzed and simulated the average BER behavior according to the average SNR for different turbulence strengths. Simulation results are demonstrated to confirm the analytical results.