• Title/Summary/Keyword: Auto correlation

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Stochastic FE Analysis of Plate Structure (평판구조의 추계론적 유한요소해석)

  • 최창근;노혁천
    • Computational Structural Engineering
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    • v.8 no.1
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    • pp.127-136
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    • 1995
  • In this paper the stochastic FE analysis considering the material and geometrical property of the plate structure is performed by the weighted integral method. To consider the stochasity of the material and geometrical property, the stochastic field is assumed respectively. The mean value of the stochastic field is 0 and the value of variance is assumed as 0.1. The characteristics of the assumed stochastic field is represented by auto-correlation function. This auto-correlation function is used in evaluating the response variability of the plate structure. In this study a new auto-correlation function is derived to concern the uncertainty of the plate thickness. The newly derived auto-correlation function is a function of auto-correlation function and coefficient of variation of the assumed stochastic field. The two results, obtained by proposed Weighted Integral method and Monte Carlo Simulation method, are coincided with each other and these results are almost equal to the theoretical result that is derived in this study. In the case of considering the variability of plate thickness, the obtained result is well coincide with those of Lawrence and Monte Carlo simulation.

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Customer perception of auto service quality using Kano-SERVQUAL integrated approach - Focusing on the auto service of 'H' company - (Kano-SERVQUAL 통합 접근법을 이용한 자동차 서비스 품질에 대한 고객인식 연구 - H사(社)의 자동차 서비스를 중심으로 -)

  • Kim, Hakgyun;Song, Haegeun;Park, Young T.
    • Journal of Korean Society for Quality Management
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    • v.44 no.4
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    • pp.965-981
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    • 2016
  • Purpose: This study aims to propose Kano-SERVQUAL integrated approach as an effective tool for evaluating auto service quality attributes to enhance the use of SERVQUAL. Methods: The Kano-SERVQUAL survey was conducted to evaluate customer perception for 28 auto service quality attributes which were obtained from auto service expert in 'H' company. The correlation analysis of SI(Satisfaction Index), DI(Dissatisfaction Index) and expectation values are conducted in this study. Results: The 28 auto service quality attributes are classified into attractive attributes and one-dimensional attributes. The results of this study show that the correlations between the customers' expectation values and DI is strongly positive correlation with 1% significance level, expectation values and SI is negative correlation with 10% significance level. Conclusion: The results show that the purposed Kano-SERVQUAL integrated approach provides a deeper understanding of service quality attributes in that it distinguishes the customers' expectation values between highly expected attributes(e.g. must-be attribute) and less expected attributes(e.g. attractive attribute).

Improved Correlation Identification of Subsurface Using All Phase FFT Algorithm

  • Zhang, Qiaodan;Hao, Kaixue;Li, Mei
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.14 no.2
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    • pp.495-513
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    • 2020
  • The correlation identification of the subsurface is a novel electrical prospecting method which could suppress stochastic noise. This method is increasingly being utilized by geophysicists. It achieves the frequency response of the underground media through division of the cross spectrum of the input & output signal and the auto spectrum of the input signal. This is subject to the spectral leakage when the cross spectrum and the auto spectrum are computed from cross correlation and autocorrelation function by Discrete Fourier Transformation (DFT, "To obtain an accurate frequency response of the earth system, we propose an improved correlation identification method which uses all phase Fast Fourier Transform (APFFT) to acquire the cross spectrum and the auto spectrum. Simulation and engineering application results show that compared to existing correlation identification algorithm the new approach demonstrates more precise frequency response, especially the phase response of the system under identification.

Image Path Searching using Auto and Cross Correlations

  • Kim, Young-Bin;Ryu, Kwang-Ryol
    • Journal of information and communication convergence engineering
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    • v.9 no.6
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    • pp.747-752
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    • 2011
  • The position detection of overlapping area in the interframe for image stitching using auto and cross correlation function (ACCF) and compounding one image with the stitching algorithm is presented in this paper. ACCF is used by autocorrelation to the featured area to extract the filter mask in the reference (previous) image and the comparing (current) image is used by crosscorrelation. The stitching is detected by the position of high correlation, and aligns and stitches the image in shifting the current image based on the moving vector. The ACCF technique results in a few computations and simplicity because the filter mask is given by the featuring block, and the position is enabled to detect a bit movement. Input image captured from CMOS is used to be compared with the performance between the ACCF and the window correlation. The results of ACCF show that there is no seam and distortion at the joint parts in the stitched image, and the detection performance of the moving vector is improved to 12% in comparison with the window correlation method.

The correlation analysis of tire airborne noise and vehicle road noise for the tire noise evaluation (Tire noise 평가를 위한 Tire airborne noise와 Vehicle road noise의 상관성 분석)

  • Lee, Min-Woo;Kim, Sung-Ho;Choi, Eun-Soo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.11a
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    • pp.654-655
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    • 2008
  • In order to investigate the availability of tire airborne noise for vehicle road noise development, We measured the noise in condition of smooth road and coarse road. The correlation coefficient was analyzed using the articulation index of the tire airborne noise and the vehicle road noise. It has been found that the correlation between the tire airborne noise and the vehicle road noise is positively strong.

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VLSI Implementation of Auto-Correlation Architecture for Synchronization of MIMO-OFDM WLAN Systems

  • Cho, Jong-Min;Kim, Jin-Sang;Cho, Won-Kyung
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.10 no.3
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    • pp.185-192
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    • 2010
  • This paper presents a hardware-efficient auto-correlation scheme for the synchronization of MIMO-OFDM based wireless local area network (WLAN) systems, such as IEEE 802.11n. Carrier frequency offset (CFO) estimation for the frequency synchronization requires high complexity auto-correlation operations of many training symbols. In order to reduce the hardware complexity of the MIMO-OFDM synchronization, we propose an efficient correlation scheme based on time-multiplexing technique and the use of reduced samples while preserving the performance. Compared to a conventional architecture, the proposed architecture requires only 27% logic gates and 22% power consumption with acceptable BER performance loss.

Reliability Analysis of VOC Data for Opinion Mining (오피니언 마이닝을 위한 VOC 데이타의 신뢰성 분석)

  • Kim, Dongwon;Yu, Song Jin
    • Journal of Intelligence and Information Systems
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    • v.22 no.4
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    • pp.217-245
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    • 2016
  • The purpose of this study is to verify how 7 sentiment domains extracted through sentiment analysis from social media have an influence on business performance. It consists of three phases. In phase I, we constructed the sentiment lexicon after crawling 45,447 pieces of VOC (Voice of the Customer) on 26 auto companies from the car community and extracting the POS information and built a seven-sensitive domains. In phase II, in order to retain the reliability of experimental data, we examined auto-correlation analysis and PCA. In phase III, we investigated how 7 domains impact on the market share of three major (GM, FCA, and VOLKSWAGEN) auto companies by using linear regression analysis. The findings from the auto-correlation analysis proved auto-correlation and the sequence of the sentiments, and the results from PCA reported the 7 sentiments connected with positivity, negativity and neutrality. As a result of linear regression analysis on model 1, we indentified that the sentimental factors have a significant influence on the actual market share. In particular, not only posotive and negative sentiment domains, but neutral sentiment had significantly impacted on auto market share. As we apply the availability of data to the market, and take advantage of auto-correlation of the market-related information and the sentiment, the findings will be a huge contribution to other researches on sentiment analysis as well as actual business performances in various ways.

The Damage Classification by Periodicity Detection of Ultrasonic Wave Signal to Occur at the Tire (타이어에서 발생하는 초음파 신호의 주기성 검출에 의한 손상 분별)

  • Oh, Young-Dal;Kang, Dae-Soo
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.10 no.6
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    • pp.107-111
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    • 2010
  • The damage of tire by damage material classification method is researched as used ultrasonic wave signal to occur at a tire during vehicle driving. Auto-correlation function after having passed through an envelope detecting preprocess is used for detecting periodicity because of occurring periodic ultrasonic waves signal with tire revolution. One revolution cycle time of a damaged tire and period that calculated auto-correlation function appeared equally in experiment. The result that can classification whether or not there was a tire damage is established.

Molecular Dynamics Simulation Study of Transport Properties of Diatomic Gases

  • Lee, Song Hi;Kim, Jahun
    • Bulletin of the Korean Chemical Society
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    • v.35 no.12
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    • pp.3527-3531
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    • 2014
  • In this paper, we report thermodynamic and transport properties (diffusion coefficient, viscosity, and thermal conductivity) of diatomic gases ($H_2$, $N_2$, $O_2$, and $Cl_2$) at 273.15 K and 1.00 atm by performing molecular dynamics simulations using Lennard-Jones intermolecular potential and modified Green-Kubo formulas. The results of self-diffusion coefficients of diatomic gases obtained from velocity auto-correlation functions by Green-Kubo relation are in good agreement with those obtained from mean square displacements by Einstein relation. While the results for viscosities of diatomic gases obtained from stress auto-correlation functions underestimate the experimental results, those for thermal conductivities obtained from heat flux auto-correlation functions overestimate the experimental data except $H_2$.

Analysis of the Parameter Convergence Rate for an Adaptive Identifier (적응추정자에 대한 파라메터 수렴속도의 해석)

  • Kim, Sung-Duck
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.38 no.2
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    • pp.127-136
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    • 1989
  • This paper describes the parameter convergence properties of an adaptive system to identify a single-input single-output plant model. It is demonstrated that, by using power spectrum analysis, the persistency of excitation (PE) condition in order to guarantee the exponential stability of the adaptive control system can be transformed into the positive definite behavior for the auto-correlation function matrix of adaptive signal. The existence of parameter nominal values can be analyzed by this condition and the convergence rates of parameter are determined by examining the auto-correlation function. We may use the sufficient richness (SR) of input spectrum instead of the PE condition to analyze the parameter boundedness. It can be shown that the eigen values of the auto-correlation function are always related with adaptive gain, input amplitude and positions or numbers of input spectra. In each case, the variation of parameter convergence rate can be also verified.

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