• The Korean Journal of Applied Statistics
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• v.29 no.7
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• pp.1445-1458
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• 2016

This paper derives a correlation coefficient using detrended cross-correlation analysis (DCCA) method for 59 regional temperature series for 40 years from 1976 to 2015. The average temperature, maximum temperature, and minimum temperature series for 4 year units are analyzed; consequently, we estimated that a temperature correlation exists between the two regions during the unit period where the correlation coefficient is greater than or equal to 0.9; subsequently, we construct a network linking the two regions. Based on network theory, average path length, clustering coefficient, assortativity, and modularity were derived. As a result, it was found that the temperature network satisfies a small-worldness property and is a network having assortativity and modularity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.8
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• pp.1471-1477
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• 2006

Electrocorticogram (ECoG) was recorded in one young adult suffering from medically refractory partial seizures a few weeks before resection. ECoG of intractable focal epilepsy was analyzed usins AR model, wavelet analysis and cross-correlation analysis. The cross-correlation of the epileptic discharges was calculated between the electrodes in every unit of time, to get the phase shift. A contour map of the phase shift and the sequential two-dimensional phase shift maps were utilized to localize the epileptic foci and to study their propagation process. More than two epileptogenic foci were localized and two kinds of propagating process were shown. These investigations suggest that epileptic phenomena can be caused by at least two kinds of mechanisms in one patient.

• Korean Journal of Applied Biomechanics
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• v.30 no.3
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• pp.205-215
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• 2020

Objective: The purpose of this study was to investigate the relative angles and cross-correlation between body segments and ski among four alpine ski turning techniques. Method: 19 alpine ski instructors participated in this study. Each skier asked to perform 4- types of turning technique, classified by radius and level. 8 inertial measurement units were used to measure orientation angle of segment and ski on the anteroposterior and vertical axis. Results: Significant differences were found between types of turning in the segments-ski relative angle on the anteroposterior and vertical axis (p<.05). Although, cross-correlation showed a high correlation between angles of segment and ski, there were significant differences between types of turning. Conclusion: Based on our results, the relative movement and timing between each segment and ski is different according to the turning techniques, so the training methods should be applied differently.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.2875-2882
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• 2013

The design of PN(Pseudo Noise) sequences with good cross-correlation properties is important for many research areas in communication systems. Also analyses of cross-correlation frequency between designed sequences have been researched. In this paper we analyze of cross-correlation distribution and properties of non-linear binary sequences family $S^r=\{Tr^m_1\{[Tr^n_m(a{\alpha}^t+{\alpha}^{dt}]^r\}{\mid}a{\in}GF(2^m),0{\leq}t &lt; 2^n-1\}$, where $gcd(r,2^m-1)=1$ with 5-valued cross-correlation.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06a
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• pp.781-784
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• 1994

Detecting partial discharge(PD) and locating its source are one of many diagnosis methods. Location the PD source is very important to reduce the time and cost of repairing power transformers. And to locate the PD source, the cross-correlation method is a well known one. But there many spurious peaks in cross-correlation, and occasionally, some peaks could be bigger than the true one. In order to analysis these spurious peaks and to reduce them, we have done many experiments and simulations. As the results we could reduce the spurious peaks, and get well defined cross-correlation from which it is easy to locate the PD source accurately.

• Smart Structures and Systems
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• v.16 no.1
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• pp.213-222
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• 2015

Early detection and precise location of leakage is of great importance for life-cycle maintenance and management of municipal pipeline system. In the past few years, acoustic emission (AE) techniques have demonstrated to be an excellent tool for on-line leakage detection. Regarding the multi-mode and frequency dispersion characteristics of AE signals propagating along a pipeline, the direct cross-correlation technique that assumes the constant AE propagation velocity does not perform well in practice for acoustic leak location. This paper presents an improved cross-correlation method based on wavelet transform, with due consideration of the frequency dispersion characteristics of AE wave and the contribution of different mode. Laboratory experiments conducted to simulate pipeline gas leakage and investigate the frequency spectrum signatures of AE leak signals. By comparing with the other methods for leak location identification, the feasibility and superiority of the proposed method are verified.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.7
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• pp.703-710
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• 2010

In this paper, an overload detecting algorithm for an excavator is presented. The proposed overload detecting algorithm is based on the time series analysis especially correlation function. The main purpose of this paper is to prevent damage or crack from the fatigue loaded on an excavator in advance. Generally, the larger data, the longer processing time, and the amount of the data used in this paper are also large, especially every sampling period, 1600 data are gathered and calculated. So this paper focuses on minimizing the number of required sensors by using the correlation function. From the cross correlation function, similar pattern sensors are eliminated and dissimilar pattern sensors are considered, and from the auto correlation function, the overload can be detected. To prove the efficiency of the proposed overload detecting algorithm, this paper shows the computer simulation results.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.1
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• pp.47-56
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• 2019

As the zero interest rate era was over with the end of quantitative easing, the economy of several global markets observed the fluctuations of the base interest rate. Interest rate, which is the change of money value with respect to time, is negatively correlated with construction investment. Considering the characteristics of interest rates and construction investment as economic variables, the necessity of cross-border analysis between base interest rate and construction investment was suggested in this paper. Cross-correlation analysis between base interest rates and construction investment crossing the border was performed. The effective correlations were confirmed with values varying by countries. Similar characteristics were also observed among countries with similar economy, which were then divided into three groups. Additionally, identifying the base interest rate that affects the construction investment of a particular country was made possible by reflecting a self-cycle of base interest rates. Lastly, from the result of examining the influence of each rise and fall of the interest rate, it was verified that the difference was more than twice as large in some countries. These results are expected to contribute to construction-related policy makers or investors to make decisions in response to the economic status of the construction market.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.2
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• pp.810-831
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• 2019

Recently, continuous dimensional emotion recognition from audiovisual clues has attracted increasing attention in both theory and in practice. The large amount of data involved in the recognition processing decreases the efficiency of most bimodal information fusion algorithms. A novel algorithm, namely the incomplete Cholesky decomposition based kernel cross factor analysis (ICDKCFA), is presented and employed for continuous dimensional audiovisual emotion recognition, in this paper. After the ICDKCFA feature transformation, two basic fusion strategies, namely feature-level fusion and decision-level fusion, are explored to combine the transformed visual and audio features for emotion recognition. Finally, extensive experiments are conducted to evaluate the ICDKCFA approach on the AVEC 2016 Multimodal Affect Recognition Sub-Challenge dataset. The experimental results show that the ICDKCFA method has a higher speed than the original kernel cross factor analysis with the comparable performance. Moreover, the ICDKCFA method achieves a better performance than other common information fusion methods, such as the Canonical correlation analysis, kernel canonical correlation analysis and cross-modal factor analysis based fusion methods.

• Journal of Wetlands Research
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• v.14 no.4
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• pp.503-518
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• 2012

Models estimating carbon budget at land surface are mainly interested in vertical flux of carbon. On the other hand, studies on horizontal flux are obviously lacked to confirm that relationship between the hydrological flux of organic carbon discharged from catchment and terrestrial carbon production, a relation between Total Organic Carbon(TOC) and Gross Primary Production(GPP) tried analysis through cross correlation. The best correlation structure is correlation between GPP and TOC of flow-weighted mean concentration from watershed without delay. Furthermore, cross correlation analysis was performed by consider periodicity. The correlation between TOC and GPP in summer was similar to correlation without periodicity. Therefore, correlation between GPP and TOC was most regulated by the correlation between GPP and TOC at summer. As a result, the vegetation carbon and organic carbon from watershed is recognized a close relationship on the seasonal. Therefore, future research is correlation analyzing between vegetation variables according season, GPP and TOC, we are expected to use quantitative understanding that horizontal flux flow of carbon from the surface.