• The Journal of the Society of Korean Medicine Diagnostics
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• v.11 no.2
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• pp.68-83
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• 2007

Background and Purpose: According to chaos theory, irregular signals of electroencephalogram can interpretated by nonlinear method. Chaotic nonlinear dynamics in EEG can be studied by calculating the correlation dimension. The aim of this study is to analyze EEG by correlation dimension and do Correlation Analysis of correlation dimension and K-POMS factors score. Method: EEG raw data were measured during 15 minutes and choosed 40 seconds. We calculated correlation dimension and used surrogate data method for checking nonlinear data. After then do correlation analysis. Result and Conclusion: Correlation dimension of channel 6, channel 7 and channel 8 are showed significant correlation with vigor factor.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.2
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• pp.27-34
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• 2014

In this paper, we investigate the statistical correlation of the time series for temperature measured at the heat box in the automobile drying process. We show, in terms of the sample variance, that a significant non-linear correlation exists in the time series that consist of absolute temperature changes. To investigate further the non-linear correlation, we utilize the volatility, an important concept in the financial market, and induce volatility time series from absolute temperature changes. We analyze the time series of volatilities in terms of the de-trended fluctuation analysis (DFA), a method especially suitable for testing the long-range correlation of non-stationary data, from the correlation perspective. We uncover that the volatility exhibits a long-range correlation regardless of the window size. We also analyze the cross correlation between two (inlet and outlet) volatility time series to characterize any correlation between the two, and disclose the dependence of the correlation strength on the time lag. These results can contribute as important factors to the modeling of forecasting and management of the heat box's temperature.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.1
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• pp.75-80
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• 2013

In this paper, We proposed a Optical Correlation for indoor positioning based LED-ID. The proposed Optical Correlation has a advantage to low-interference between spread code number sequences and LED-ID. it is applied a spread code to reduce the interference with additional information based LED-ID. The additional information is enable to detect in transmitted signal using auto correlation. Also we designed and implemented the Optical Correlation for clearly detecting the additional information. Simulations were performed to confirm the performance of BER and the power of additional information. Optical Correlation simulator to indoor positioning based LED-ID was implemented to prove a usefulness.

• Journal of the Korean Data and Information Science Society
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• v.17 no.4
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• pp.1129-1139
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• 2006

Pearson's correlation coefficient and vector similarity are generally applied to The users' similarity weight of user based recommender system. This study is needed to find that the correlation coefficient of similarity weight is effected by the number of pair response and significance probability. From the classified correlation coefficient by the significance probability test on the correlation coefficient and pair of response, the change of MAE is studied by comparing the predicted precision of the two. The results are experimentally related with the change of MAE from the significant correlation coefficient and the number of pair response.

• ETRI Journal
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• v.30 no.6
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• pp.765-773
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• 2008

Spatial correlation is a result of insufficient antenna spacing among multiple antenna elements, while temporal correlation is caused by Doppler spread. This paper compares the effect of spatial and temporal correlation in order to investigate the performance of multiuser scheduling algorithms in multiple-input multiple-output (MIMO) broadcast channels. This comparison includes the effect on the ergodic capacity, on fairness among users, and on the sum-rate capacity of a multiuser scheduling algorithm utilizing statistical channel state information in spatio-temporally correlated MIMO broadcast channels. Numerical results demonstrate that temporal correlation is more meaningful than spatial correlation in view of the multiuser scheduling algorithm in MIMO broadcast channels. Indeed, the multiuser scheduling algorithm can reduce the effect of the Doppler spread if it exploits the information of temporal correlation appropriately. However, the effect of spatial correlation can be minimized if the antenna spacing is sufficient in rich scattering MIMO channels regardless of the multiuser scheduling algorithm used.

• Journal of Applied Reliability
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• v.18 no.3
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• pp.208-212
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• 2018

Purpose: The three Vs of volume, velocity and variety are commonly used to characterize different aspects of Big Data. Volume refers to the amount of data, variety refers to the number of types of data and velocity refers to the speed of data processing. According to these characteristics, the size of Big Data varies rapidly, some data buckets will contain outliers, and buckets might have different sizes. Correlation plays a big role in Big Data. We need something better than usual correlation measures. Methods: The correlation measures offered by traditional statistics are compared. And conditions to meet the characteristics of Big Data are suggested. Finally the correlation measure that satisfies the suggested conditions is recommended. Results: Mutual Information satisfies the suggested conditions. Conclusion: This article builds on traditional correlation measures to analyze the co-relation between two variables. The conditions for correlation measures to meet the characteristics of Big Data are suggested. The correlation measure that satisfies these conditions is recommended. It is Mutual Information.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.2
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• pp.85-93
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• 2016

The existence of correlation characteristics brings significant potential advantages to the development of efficient routing protocols in wireless sensor networks. This research proposes a new simple method of clustering sensor nodes into correlation groups in multiple-correlation areas. At first, the evaluation of joint entropy for multiple-sensed data is considered. Based on the evaluation, the definition of correlation region, based on entropy theory, is proposed. Following that, a correlation clustering scheme with less computation is developed. The results are validated with a real data set.

• Bulletin of the Korean Chemical Society
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• v.24 no.9
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• pp.1345-1350
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• 2003

Principal component analysis based two-dimensional (PCA-2D) correlation analysis is applied to FTIR spectra of polystyrene/methyl ethyl ketone/toluene solution mixture during the solvent evaporation. Substantial amount of artificial noise were added to the experimental data to demonstrate the practical noise-suppressing benefit of PCA-2D technique. 2D correlation analysis of the reconstructed data matrix from PCA loading vectors and scores successfully extracted only the most important features of synchronicity and asynchronicity without interference from noise or insignificant minor components. 2D correlation spectra constructed with only one principal component yield strictly synchronous response with no discernible a asynchronous features, while those involving at least two or more principal components generated meaningful asynchronous 2D correlation spectra. Deliberate manipulation of the rank of the reconstructed data matrix, by choosing the appropriate number and type of PCs, yields potentially more refined 2D correlation spectra.

• Restorative Dentistry and Endodontics
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• v.49 no.2
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• pp.21.1-21.8
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• 2024

Objectives: This paper aims to serve as a useful guide for sample size determination for various correlation analyses that are based on effect sizes and confidence interval width. Materials and Methods: Sample size determinations are calculated for Pearson's correlation, Spearman's rank correlation, and Kendall's Tau-b correlation. Examples of sample size statements and their justification are also included. Results: Using the same effect sizes, there are differences between the sample size determination of the 3 statistical tests. Based on an empirical calculation, a minimum sample size of 149 is usually adequate for performing both parametric and non-parametric correlation analysis to determine at least a moderate to an excellent degree of correlation with acceptable confidence interval width. Conclusions: Determining data assumption(s) is one of the challenges to offering a valid technique to estimate the required sample size for correlation analyses. Sample size tables are provided and these will help researchers to estimate a minimum sample size requirement based on correlation analyses.

• Journal of Engineering Education Research
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• v.16 no.6
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• pp.38-44
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• 2013

This study has the purpose to identify the correlation of engineering education major college students' technological problem solving tendency between technological problem solving capability. To that end, the technological problem solving tendencies of 79 students enrolled in engineering education related department in college of education, 'C' University located in Daejeon metropolitan city were examined, and the correlation of technological problem solving tendency between technological problem solving capability was analyzed through measurement of technological problem solving capability. As for the correlation among problem solving confidence a sub-element of technological problem solving tendency and technological problem solving capability, positive correlation was found in result 3, result 4 and result average. As for the correlation among approach-avoidance tendency a sub-element of technological problem solving tendency and technological problem solving capability, positive correlation was found in result 5 and result average. As for the correlation among self-control recognition degree the sub-element of technological problem solving tendency and technological problem solving capability, positive correlation was found in result 1, result 3 and result average. As for the correlation among problem solving tendency and technological problem solving capability, positive correlation was found in result 3, result 4, result 5 and result average.