• Title/Summary/Keyword: cross correlation functions

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A Study on Development of Commercial PIV Utilizing Multimedia (멀티미디어 대응 상용 PIV의 국산화개발에 관한 연구)

  • 최장운
    • Journal of Advanced Marine Engineering and Technology
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    • v.22 no.5
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    • pp.652-659
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    • 1998
  • The present study is aimed to develop a new PIV operating software through optimization of vector tracking identification including versatile pre-processings and post-processing techniques. And the result exhibits an improved version corresponding various input and output multimedia compared to previous commercial software developed by other makers. An upgraded identification method called grey-level cross correlation coefficient method by direct calculation is suggested and related user-friendly pop-up menu are also represented. Post-processings comprising turbulence statistics are also introduced with graphic output functions.

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Modelling of Rayleigh and Rician Mobile Fading Channel (Rayleigh 및 Rician 페이딩 이동 채널 모델링)

  • Nam, Gi-Jin
    • 전자공학회논문지 IE
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    • v.44 no.4
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    • pp.41-47
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    • 2007
  • In this paper, the performance of simulation model in mobile to mobile Rayleigh and Rician fading channel is analyzed and simulation results are compared. The auto-correlation and cross-correlation functions of Rayleigh fading channels not only based on received signals of Clarke's fading model and but also based on received signals of phase shifted Clarke's fading model are derived and their simulation results are found. The two models are also applied to mobile to mobile Rician fading channel models and their numerical results of auto-correlation functions of complex envelop received signals shows the statistical properties match the theoretical values very well and rapidly converge with the small number such as N=8.

Combining Different Distance Measurements Methods with Dempster-Shafer-Theory for Recognition of Urdu Character Script

  • Khan, Yunus;Nagar, Chetan;Kaushal, Devendra S.
    • International Journal of Ocean System Engineering
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    • v.2 no.1
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    • pp.16-23
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    • 2012
  • In this paper we discussed a new methodology for Urdu Character Recognition system using Dempster-Shafer theory which can powerfully estimate the similarity ratings between a recognized character and sampling characters in the character database. Recognition of character is done by five probability calculation methods such as (similarity, hamming, linear correlation, cross-correlation, nearest neighbor) with Dempster-Shafer theory of belief functions. The main objective of this paper is to Recognition of Urdu letters and numerals through five similarity and dissimilarity algorithms to find the similarity between the given image and the standard template in the character recognition system. In this paper we develop a method to combine the results of the different distance measurement methods using the Dempster-Shafer theory. This idea enables us to obtain a single precision result. It was observed that the combination of these results ultimately enhanced the success rate.

Interior Noise Characteristics in Japanese, Korean and Chinese Subways

  • Soeta, Yoshiharu;Shimokura, Ryota;Jeon, Jin Yong;Lee, Pyoung Jik
    • International Journal of Railway
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    • v.6 no.3
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    • pp.120-124
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    • 2013
  • The aim of this study was to clarify the characteristics of interior noise in Japanese, Korean, and Chinese subways. The octave-band noise levels, A-weighted equivalent continuous sound pressure level ($L_{Aeq}$) and parameters extracted from interaural cross-correlation/autocorrelation functions (ACF/IACFs) were analyzed to evaluate the noise inside running train cars quantitatively and qualitatively. The average $L_{Aeq}$ was 72-83 dBA. The IACF/ACF parameters of the noise showed variations in their values, suggesting they are affected by the characteristics of the trains running, wheel-rail interaction, and cross-section of the tunnels.

Comparison of Hydrogeological Time Series Analysis Results Before and After Detrending (변동경향성 제거 전후의 수리지질학적 시계열분석 결과 비교)

  • Lim, Hong-Gyun;Choi, Hyun-Mi;Lee, Jin-Yong
    • Journal of Soil and Groundwater Environment
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    • v.16 no.2
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    • pp.30-40
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    • 2011
  • In this study, we compared the analysis results before and after the detrending for the data. According to the comparison results, correlation functions were not much changed while autocorrelation and spectral density functions were largely varied. Especially, time series data with a long-term variation trend showed a distinctive difference. This study demonstrated a usefulness of the detrending for a further analysis.

Performance Analysis of Matching Cost Functions of Stereo Matching Algorithm for Making 3D Contents (3D 콘텐츠 생성에서의 스테레오 매칭 알고리즘에 대한 매칭 비용 함수 성능 분석)

  • Hong, Gwang-Soo;Jeong, Yeon-Kyu;Kim, Byung-Gyu
    • Convergence Security Journal
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    • v.13 no.3
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    • pp.9-15
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    • 2013
  • Calculating of matching cost is an important for efficient stereo matching. To investigate the performance of matching process, the concepts of the existing methods are introduced. Also we analyze the performance and merits of them. The simplest matching costs assume constant intensities at matching image locations. We consider matching cost functions which can be distinguished between pixel-based and window-based approaches. The Pixel-based approach includes absolute differences (AD) and sampling-intensitive absolute differences (BT). The window-based approach includes the sum of the absolute differences, the sum of squared differences, the normalized cross-correlation, zero-mean normalized cross-correlation, census transform, and the absolute differences census transform (AD-Census). We evaluate matching cost functions in terms of accuracy and time complexity. In terms of the accuracy, AD-Census method shows the lowest matching error ratio (the best solution). The ZNCC method shows the lowest matching error ratio in non-occlusion and all evaluation part. But it performs high matching error ratio at the discontinuities evaluation part due to blurring effect in the boundary. The pixel-based AD method shows a low complexity in terms of time complexity.

Comparison and Correlation between Physical and Psychological Functions by Gender in Judo Athletes (유도선수의 성별에 따른 신체적, 심리적 기능 비교 및 상관관계 연구)

  • Hyeyoung Kim;Eunjung Chung;Ye-Jin Shin;Byoung-Hee Lee
    • Journal of Korean Physical Therapy Science
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    • v.30 no.4
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    • pp.71-81
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    • 2023
  • Background: The purpose of this study was to comparison and correlation between physical and psychological functions by gender in Judo athletes. Both the physical and psychological factors of athletes are important as factors influencing athletic performance, but there are few papers that have compared and studied the correlation between physical and psychological functions of judo players. Design: Cross sectional study Methods: The 134 participants; high school students, college students, and team players. They used physical functions to measure such as self-describing KOOS, FAOS, ODI, POMS, SCAT, ASMQ, and ACSI-28. Results: There was a significant difference in the physical function according to gender in the KOOS, but no significant difference in the FAOS and ODI. For psychological function, there was a significant difference in the vitality item in the POMS, and a significant difference in the body management, training management, life management, and unique behavior management items in the ASMQ. In the ACSI-28, there were significant differences in coping with adversity, stress repayment, concentration, freedom to worry about matches, and self-coaching behavior items. Physical function and psychological function showed a significant negative correlation. The POMS showed a negative correlation between the ASMQ and ACSI-28, whereas the SCAT showed a positive correlation. Conclusion: The results of this study are expected to be used as a basic data for sports training by gender of Judo athletes.

Derivation of Relationship between Cross-site Correlation among data and among Estimators of L-moments for Generalize Extreme value distribution (Generalized Extreme Value 분포 자료의 교차상관과 L-모멘트 추정값의 교차상관의 관계 유도)

  • Jeong, Dae-Il
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.3B
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    • pp.259-267
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    • 2009
  • Generalized Extreme Value (GEV) distribution is recommended for flood frequency and extreme rainfall distribution in many country. L-moment method is the most common estimation procedure for the GEV distribution. In this study, the relationships between the cross-site correlations between extreme events and the cross-correlation of estimators of L-moment ratios (L-moment Coefficient of Variation (L-CV) and L-moment Coefficient of Skewness (L-CS)) for data generated from GEV distribution were derived by Monte Carlo simulation. Those relationships were fit to the simple power function. In this Monte Carlo simulation, GEV+ distribution were employed wherein unrealistic negative values were excluded. The simple power models provide accurate description of the relationships between cross-correlation of data and cross-correlation of L-moment ratios. Estimated parameters and accuracies of the power functions were reported for different GEV distribution parameters combinations. Moreover, this study provided a description about regional regression approach using Generalized Least Square (GLS) regression method which require the cross-site correlation among L-moment estimators. The relationships derived in this study allow regional GLS regression analyses of both L-CV and L-CS estimators that correctly incorporate the cross-correlation among GEV L-moment estimators.

Error Performance Analysis of DS-CDMA System in Wireless Channel

  • Kang, Heau-Jo
    • Journal of information and communication convergence engineering
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    • v.1 no.1
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    • pp.1-5
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    • 2003
  • This paper discusses the spectral efficiency and performance of asynchronous direct sequency spread spectrum multiple access systems strict bandwidth limitation by Nyquist filtering. The signal to noise plus interference ratio(SNIR) at the output from the correlation receiver is derived analytically taking the cross correlation characteristics of spreading sequences into account, and also an approximated SNIR of a simple form is presented for the systems employing Gold sequences. Based on the analyzed result of SNIR, bit error rate performance and spectral efficiency are also estimated. and at last, we analyzed improvement rate using RS, convolution as a method for improving functions.

Circadian Biorhythmicity in Normal Pressure Hydrocephalus - A Case Series Report

  • Herbowski, Leszek
    • Journal of Korean Neurosurgical Society
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    • v.65 no.1
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    • pp.151-160
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    • 2022
  • Continuous monitoring of intracranial pressure is a well established medical procedure. Still, little is known about long-term behavior of intracranial pressure in normal pressure hydrocephalus. The present study is designed to evaluate periodicity of intracranial pressure over long-time scales using intraventricular pressure monitoring in patients with normal pressure hydrocephalus. In addition, the circadian and diurnal patterns of blood pressure and body temperature in those patients are studied. Four patients, selected with "probable" normal pressure hydrocephalus, were monitored for several dozen hours. Intracranial pressure, blood pressure, and body temperature were recorded hourly. Autocorrelation functions were calculated and cross-correlation analysis were carried out to study all the time-series data. Autocorrelation results show that intracranial pressure, blood pressure, and body temperature values follow bimodal (positive and negative) curves over a day. The cross-correlation functions demonstrate causal relationships between intracranial pressure, blood pressure, and body temperature. The results show that long-term fluctuations in intracranial pressure exhibit cyclical patterns with periods of about 24 hours. Continuous intracranial pressure recording in "probable" normal pressure hydrocephalus patients reveals circadian fluctuations not related to the day and night cycle. These fluctuations are causally related to changes in blood pressure and body temperature. The present study reveals the complete loss of the diurnal blood pressure and body temperature rhythmicities in patients with "probable" normal pressure hydrocephalus.