• Title/Summary/Keyword: Cross-correlation Analysis

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A Study on the Emotion State Classification using Multi-channel EEG (다중채널 뇌파를 이용한 감정상태 분류에 관한 연구)

  • Kang, Dong-Kee;Kim, Heung-Hwan;Kim, Dong-Jun;Lee, Byung-Chae;Ko, Han-Woo
    • Proceedings of the KIEE Conference
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    • 2001.07d
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    • pp.2815-2817
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    • 2001
  • This study describes the emotion classification using two different feature extraction methods for four-channel EEG signals. One of the methods is linear prediction analysis based on AR model. Another method is cross-correlation coefficients on frequencies of ${\theta}$, ${\alpha}$, ${\beta}$ bands. Using the linear predictor coefficients and the cross-correlation coefficients of frequencies, the emotion classification test for four emotions, such as anger, sad, joy, and relaxation is performed with a neural network. Comparing the results of two methods, it seems that the linear predictor coefficients produce the better results than the cross-correlation coefficients of frequencies for-emotion classification.

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Time Series Analysis of the Responses of the Groundwater Levels at Multi-depth Wells According to the River Stage Fluctuations (시계열 분석을 이용한 하천수위에 따른 다심도 관정의 지하수위 변동해석)

  • Ha Kyoo-Chul;Ko Kyung-Seok;Koh Dong-Chan;Yum Byoung-Woo;Lee Kang-Kun
    • Economic and Environmental Geology
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    • v.39 no.3 s.178
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    • pp.269-284
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    • 2006
  • Aquifer responses to the river stage fluctuations were analyzed between the groundwater level and the river stage in an alluvial aquifer. The auto-correlation and cross-correlation as a time series analysis were applied. Study site is a floodplain in the Mangyeong river. Groundwater levels in each depth representing the silt and sand(SS), gravel and sand(GS), and weathered zone(WZ) layer were monitored. The groundwater levels were more sensitive to the river stage fluctuations than rainfall. Since the river stages are influenced by the gate operations downstream and tide, show periodic patterns, and the correlation coefficients with rainfall is low. Cross-correlation function between groundwater level in each depth do not show any delay time, then response time is very short to each depth. Cross-correlation analysis were performed to estimate the response time of groundwater levels to river stage fluctuations. Groundwater levels respond to the river stage within 30 minutes to 1 hour in wells near the stream. Short time lag between groundwater level and river stage indicates the quick response. A different response time imply the hydraulic inhomogeneity of the site, and a probable high permeability zone between river and aquifer can be inferred. Mangyeong-river in study site is a gaining stream normally, and river stage rising by gate operation or floods makes river water flow into groundwater. The auto-correlation and cross-correlation functions as a time series analysis can be a good tool to interpret the aquifer responses to stream stage fluctuation

Exclusive correlation analysis for algae and environmental factors in weirs of four major rivers in South Korea (4대강 주요지점에서의 조류 발생인자의 배타적 상관성분석에 대한 연구)

  • Lee, Eun Hyung;Kim, Yeonhwa;Kim, Kyunghyun;Kim, Sanghyun
    • Journal of Korea Water Resources Association
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    • v.49 no.2
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    • pp.155-164
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    • 2016
  • Algal blooms not only destroy fish habitats but also diminish biological diversity of ecosystem which results into water quality deterioration of 4 major rivers in South Korea. The relationship between algal bloom and environmental factors had been analyzed through the cross-correlation function between concentration of chlorophyll a and other environmental factors. However, time series of cross-correlations can be affected by the stochastic structure such auto-correlated feature of other controllers. In order to remove external effect in the correlation analysis, the pre-whitening procedure was implemented into the cross correlation analysis. The modeling process is consisted of a series of procedure (e.g., model identification, parameter estimation, and diagnostic checking of selected models). This study provides the exclusive correlation relationship between algae concentration and other environmental factors. The difference between the conventional correlation using raw data and that of pre-whitened series was discussed. The process implemented in this paper is useful not only to identify exclusive environmental variables to model Chl-a concentration but also in further extensive application to configure causality in the environment.

Correlation Coefficients and Path - Analysis of Various Characteristics of Dihaploids derived from Tobacco (Nicotiana tabacco L.)Anther Culture in vitro (담배 약에서 유기된 반수체 배가계통의 변이, 상관 및 경로분석)

  • 금완수;제상율
    • Journal of the Korean Society of Tobacco Science
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    • v.3 no.1
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    • pp.41-48
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    • 1981
  • Dihaploid lines were derived from the anthers of the F, of single cross, "Va 115" x"SC 72" (Nicotiana tabacum L.). The path-analysis, correlation coefficient, and variation of characteristics among dihaploid families were evaluated. Dihaploid lines displayed much greater variation than their parents. The genetic correlation coefficient between yield and total alkaloids of dihaploids was significantly lower than that of conventional varieties and lines. In path-analysis which relates yield components to yield, number of leaves harvested and leaf width had a direct effect on yield. a direct effect on yield.

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Effect of Cross-legged Sitting Posture on Joint Range of Motion: Correlation with Musculoskeletal Symptoms and Facial Asymmetry

  • Shin, Yeong hui
    • The Journal of Korean Physical Therapy
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    • v.34 no.5
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    • pp.255-266
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    • 2022
  • Purpose: This study sought to study the effects of cross-legged sitting posture on joint motion. It also examined the correlation between the changes in the joint range of motion, musculoskeletal symptoms, and facial asymmetry. Methods: The Acumar Digital Inclinometer (Lafayette Instrument Company, USA) was used to measure the range of motion (ROM). We measured the flexion and extension of the cervical, thoracic, and lumbar spine using a dual inclinometer, and measured the ROM of the shoulder and hip joint with a single inclinometer. The Likert scale questionnaire was used to investigate musculoskeletal symptoms and facial asymmetry. Results: The data analysis was performed using the Jamovi version 1.6.23 statistical software. After confirming the normality of the ROM with descriptive statistics, it was compared with the normal ROM through a one-sample t-test. Correlation matrix analysis was performed to confirm the association between facial asymmetry and musculoskeletal symptoms. The result of the one-sample t-test showed a significant increase in the thoracic spine extension and right and left hip external rotation (p<0.001***), while most other joints were restricted. As per the frequency analysis, facial asymmetry was found to be 81.70%. Conclusion: The independent variable, namely cross-legged sitting posture led to an increase in ROM. The study also suggests that facial asymmetry and musculoskeletal symptoms could occur. Therefore, to prevent the increase and limitation of ROM and to prevent the occurrence of facial asymmetry and musculoskeletal symptoms, it is suggested that the usual cross-legged sitting posture should be avoided.

General Purpose Cross-section Analysis Program for Composite Rotor Blades

  • Park, Il-Ju;Jung, Sung-Nam;Kim, Do-Hyung;Yun, Chul-Yong
    • International Journal of Aeronautical and Space Sciences
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    • v.10 no.2
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    • pp.77-85
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    • 2009
  • A two-dimensional cross-section analysis program based on the finite element method has been developed for composite blades with arbitrary cross-section profiles and material distributions. The modulus weighted approach is used to take into account the non-homogeneous material characteristics of advanced blades. The CLPT (Classical Lamination Plate Theory) is applied to obtain the effective moduli of the composite laminate. The location of shear center for any given cross-sections are determined according to the Trefftz' definition while the torsion constants are obtained using the St. Venant torsion theory. A series of benchmark examples for beams with various cross-sections are illustrated to show the accuracy of the developed cross-section analysis program. The cross section cases include thin-walled C-channel, I-beam, single-cell box, NACA0012 airfoil, and KARI small-scale blades. Overall, a reasonable correlation is obtained in comparison with experiments or finite element analysis results.

A Comparative Content Analysis on the Journal of International Marketing: A Study of Ten Years (2004-2013)

  • Shin, Dong-Jin
    • Journal of Distribution Science
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    • v.12 no.5
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    • pp.81-92
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    • 2014
  • Purpose - This paper aims to investigate topics and trends in international marketing and cross-cultural management by conducting a content analysis of the Journal of International Marketing. Research Design, Data, and Methodology - In this study, one of the leading journals in the field of international marketing, the Journal of International Marketing, was chosen for research. A total of 199 articles were identified from a time span of ten years (2004-2013). SPSS software was used for codification and analysis of the data. Results - This study revealed some of the factors on which cross-cultural management had a strong correlation with international marketing. Of the 199 articles in the Journal of International Marketing, 64 articles related to cross-cultural management. Conclusions - A content analysis of the Journal of International Marketing comparing general articles with articles related to cross-cultural management is unprecedented. This study offers insight into the impact of cross culture on the discipline of international marketing. The findings of this research could be employed as a reference for gaining insight into the trends and influence of cross-cultural management in international marketing.

An Improved Technology Appraisal Model Considering Macroeconomic Variable : A Case of KOTEC (거시경제변수를 고려한 기술평가모형의 개선 : 기술보증기금의 사례)

  • Kim, Dae Cheol;Kim, Jae Bum;Cho, Keun Tae
    • Korean Management Science Review
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    • v.30 no.2
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    • pp.117-132
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    • 2013
  • The objective of this paper is to provide an improved technology appraisal model, which considers a variety of macroeconomic variables such as consumer price index and producer price index. The improved model was built using cross correlation analysis and logistic regression analysis. The AUROC analysis showed that goodness-of-fit of the proposed model turned out to be improved than that of the existing model. The model proposed in the paper would be helpful for making a reasonable investments and financing decision, lessening the default rates by systematic risk management, and enhancing the technology commercialization capabilities.

Effect of Hematological Factors on the Risk Index of Cardiovascular Disease (혈액학적 인자가 심혈관 질환 위험지수에 미치는 영향)

  • Hyun An;Hyun-Seo Yoon;Chung-Mu Park
    • Journal of radiological science and technology
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    • v.46 no.4
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    • pp.303-313
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    • 2023
  • This study aimed to investigate the relevance of cardiovascular disease risk factors AI and AIP, divided into three groups, among 300 individuals who underwent health checkups at the hospital. Various variables such as Age, Sex, BMI, WC, TC, TG, HDL-C, LDL-C, FBS, HbA1C, SBP, DBP, HR, AI (TC/HDL-C), and AIP (log(TG/HDL-C)) were analyzed using statistical methods including frequency analysis, cross-tabulation, one-way ANOVA, Pearson's correlation analysis, and multiple linear regression analysis. The cross-analysis based on cardiovascular disease risk criteria revealed that men and individuals in their 50s had higher cardiovascular disease risk based on AI and AIP. Significant differences were observed in TG, TC, HDL-C, LDL-C, SBP, DBP, AI (TC/HDL-C), and AIP (log(TG/HDL-C)) according to AI criteria. For the AIP criteria, TG, TC, HDL-C, FBS, HbA1C, HR, AI (TC/HDL-C), and AIP (log(TG/HDL-C)) were identified as cardiovascular disease risk factors. FBS and HbA1c showed the highest positive correlation In the correlation analysis, followed by TC and LDL-C. The lowest positive correlation was observed between LDL-C and DBP. In terms of negative correlation, HDL-C and AI had the highest negative correlation, while LDL-C and TG showed the lowest negative correlation. Multiple regression analysis indicated that the AI and AIP risk criteria had explanatory powers of 73.6% and 72.5%, respectively. HDL-C had the greatest negative effect on the AI risk criterion, while TG had the most significant influence on the AIP risk criterion. In conclusion, while other serological variables are important, managing HDL-C and TG levels may help reduce the risk of cardiovascular disease.

Revisiting the measurement of keratinized gingiva: a cross-sectional study comparing an intraoral scanner with clinical parameters

  • Ahmet Mert Nalbantoglu;Deniz Yanik
    • Journal of Periodontal and Implant Science
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    • v.53 no.5
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    • pp.362-375
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    • 2023
  • Purpose: The aim of this study was to investigate the relationships between gingival thickness (GT) and keratinized gingiva width (KGW), papilla height (PH), and crown ratio (CR) by employing transgingival probing and an intraoral scanner (IOS). Methods: This cross-sectional study examined 360 maxillary anterior teeth from 60 patients. GT was assessed using transgingival probing with an endodontic spreader. KGW, CR, and PH were measured using an IOS. One-way analysis of variance, the Student's t-test, and Spearman correlation coefficients were employed for statistical analysis. Results: Higher GT was significantly associated with thinner KGW in the central region (P=0.019). There was no statistically significant difference in GT between teeth (P=0.06). PH was lower in lateral teeth than in canines (P=0.047), with a PH of 2.99 mm in lateral teeth. The KGW was narrower in canines than in central teeth (P=0.007). A moderate correlation was observed between KGW and PH in the central region (P=0.01), while a weak negative correlation was found between KGW and CR (P=0.043). Conclusions: A moderate negative correlation was found between GT and KGW, as well as between PH and KGW in central teeth. In contrast, a weak negative correlation existed between CR and KGW. The PH (2.99 mm) was lower in lateral teeth than in canines. The traditional paradigm, which suggests a positive correlation between KGW and GT, was reevaluated by measuring KGW using an IOS.