• Wind and Structures
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• v.16 no.5
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• pp.491-515
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• 2013

Wind pressure characteristics on a double tower high-rise structure, which is disturbed by surrounding buildings, were investigated using large eddy simulation (LES) and 1:300 scale wind tunnel experiments. The computational simulation technique and wind tunnel experimental technique were described in detail initially. Comparisons of computational results with the experimental data have subsequently been carried out to validate the reliability of LES. Comparisons have been performed in detail for the mean and fluctuating pressure coefficients. Detailed explanations of each comparison were given in the paper. To study further on the pressure coefficients on the building surfaces, parametric studies on shape coefficient and spatial correlation were performed and investigated. The numerical and experimental results presented in this paper advance understanding on wind field around buildings and the application of LES and wind tunnel tests.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.183-186
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• 2001

In this paper, we first propose new texture features, BVLC (block variation of local correlation coefficients) moments, for content-based image retrieval (CBIR) and then present an image retrieval method based on the fusion of BDIP and BVLC moments. BDIP uses the local probabilities in image blocks to extract valley and edges well. BVLC uses the variations of local correlation coefficients in images blocks to measure texture smoothness well. In order not to be affected with the movement, rotation, and size of an object, the first and second moments of BDIP and BVLC are used for CBIR. Corel DB and Vistex DB are used to evaluate the performance of the proposed retrieval method. Experimental results show that the presented retrieval method yields average 12% better performance than the method using only BDIP or BVLC moments and average 13% better performance than the method using wavelet moments.

• Journal of the Ergonomics Society of Korea
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• v.17 no.1
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• pp.37-46
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• 1998

A human sensibility ergonomics design supporting system was applied to the product development for the customer's satisfaction based on ergonomics technology. The system is composed of three major subsystems such as customer's sensibility analysis, inference mechanism, and presentation technology. The main approaches of the system are to analyze customer's sensibilities and to translate them into product design elements. The purpose of this paper is to develop a design supporting system in which the relationship between customer's sensibility and product design elements is reasoned by a MADM(Multi-Attribute Decision Making) fuzzy model. In this model, three variables such as multiple correlation coefficients, partial correlation coefficients, and category scores were used in reasoning process. The weighted value of the words were also considered in fuzzy decision process. As a case study, the design supporting system with the MADM fuzzy model was applied to the personnel computer design.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2895-2898
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• 2003

In this study, our primary goal is to classify the EMG(electromyographic) signals including the specific patterns related to hand motions in an arm. To do this, the EMG recognition method based on the LP coefficients and delay between multi-channels obtained by cross-correlation function is presented. The study consists of three functional parts, which are pans for obtaining the EMG signals from am muscle, analyzing LP coefficients and delay parameter obtained by cross-correlation function, and recognizing specific patterns. In the experiment, the result of the present method is compared with the results of the conventional methods. We expect that the results of this study is very effective in the mobile computer and wearable computer environment.

• Journal of Electrochemical Science and Technology
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• v.8 no.4
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• pp.344-355
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• 2017

In this study, a numerical approach is adopted to investigate the effectiveness factors for distributed electrochemical reactions in thin active reaction layers of solid oxide fuel cells (SOFCs), taking into account the Butler-Volmer reaction kinetics. The mathematical equations for the electrochemical reaction and charge conduction process were formulated by assuming that the active reaction layer has a small thickness, homogeneous microstructure, and high effective electronic conductivity. The effectiveness factor is defined as the ratio of the actual reaction rate (or equivalently, current generation rate) in the active reaction layer to the nominal reaction rate. From extensive numerical calculations, the effectiveness factors were obtained for various charge transfer coefficients of 0.3-0.8. These effectiveness data were then fitted to simple correlation equations, and the resulting correlation coefficients are presented along with estimated magnitude of error.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.11
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• pp.189-192
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• 1995

In Visually Evoked Potentials(VEP) or Auditory Evoked Potentials(AEP), the components by the stimulation and the components which are irrelevant to the stimulation(noise or nonstationary spontaneous EEG) are mixed together. So one should average hundreds of EP waves to extract the components by the stimulation only. In this study, we have classified EP's, which are the responses of the different stimulations and different states of subjects. To classify the EP waves, the cross-correlation coefficients and neural network method(error back propagation) are used and compared.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.6-8
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• 2005

The forest soils of 92 sites in Korea were analyzed to survey heavy metal background levels using aqua regia digestion method and 0.1N HCl extraction method. From these results, the average natural contents of heavy metals were Cd 0.287, Cu 15.26, Pb 18.43, Cr 25.36, Zn 54.27, Ni 17.68mg/kg for aqua regia method, and Cd 0.040, Cu 0.48, Pb 3.06, Cr 0.09, Zn 1.54, Ni 0.27mg/kg for 0.1N HCl extraction method. The range of correlation coefficients between heavy metal contents obtained from two methods(aqua regia and 0.1N HCl) was significant as $0.24{\sim}0.88$, and the correlation coefficients were decreased in order of Cd, Pb, Cu, Ni, Cr, Zn.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.425-428
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• 1999

The radar interferogram represents phase differences between the two synthetic aperture radar observations acquired in slightly different angle. The success of the radar interferometric application largely depends on the quality of the interferogram generated from two or more synthetic aperture radar data sets. We propose here to apply the wavenumber correlation analysis to the in-phase and quadrature phase of the radar interferogram. The wavenumber correlation analysis is to resolve the highly correlated components from the low correlation components by estimating correlation coefficients for each wavenumber component. Through this approach, one can easily distinguish the signal components from the noise components in the wavenumber domain. Therefore, the wavenumber correlation analysis of the radar interferogram can be utilized to design post filter and to estimate the quality of interferogram. We have tested the wavenumber correlation analysis using a Radarsat SAR data pair to demonstrated the effectiveness of

• Journal of Nutrition and Health
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• v.33 no.2
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• pp.202-215
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• 2000

Intake frequency of one food is often associated with other food items, but few studies examined the relationship of food intake frequency among food items. Finding the relationship among intake frequencies of different food might be useful to understand the food intake patterns of population and correlated foods would be used as an indicators of another food intake. Relationship of food intake can be also applied to make a more simple and useful form of food frequency questionnaire to assess the association between diet and various diseases. The objective of this study was to examine the correlation of intake frequency among food items in food frequency questionnaire (FFQ). A FFQ with 84 food items was administered to 14533 Korean males who 40-65 years of age participating Korean cancer research survey. Data fromm 7647 subjects who completed FFQ were used to examine correlation among food items with three different methods-log linear regression models, Spearman correlation coefficients and cell frequency distribution. To examine the rank correlation, coefficients were calculated by Spearman correlation after scoring the frequency categories. Three most correlated foods were selected in every food intems by three methods each. In most food items, there was positive correlatin, except cooked rice and cooked brown rice, in intake frequency between foods that belonged to similar food groups. But serveral food items-Sausage (processed fish, cheese), Milk (whilte bread, orange juice), Soymilk(other juices), Cheese (pizza, butter), and Coffee(thick beef soup)-showed correlation among totally different food groups. Two sets of food items which were selected by log linear regression model and Sperman correlation coefficients were compared. There were exactly three common foods in 18 food items, 2 common foods in 47 items, 1 common food in 16 items and no common food in 3 items among 3 ranked foods. Three sets of selected food were compared. There were exactly three common foods in 5 food items, 2 common foods in 21 items, 1 common food in 34items and no common food in 24 items among 3 ranked foods. These results indicate that certain patterns exist among intake frequencies of specific food items in the FFQ. More researches are suggested to understand the relationshiops among the intakes of foods so that this information can be used in developing better FFQ or analyzing missing items from self-administered FFQ.

• Journal of Medicine and Life Science
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• v.19 no.1
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• pp.20-25
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• 2022

This study aimed to examine the changes in the Numerical Rating Scale (NRS), Oswestry Disability Index (ODI), and Roland Morris Disability Questionnaire (RMDQ) scores before and after epidural steroid injection (ESI) in patients with lower back pain, and the correlation between the three scales in patients with reduced scores on these scales. Patients completed the NRS, ODI, and RMDQ before and after receiving ESI. A paired t-test was performed to compare the mean scores obtained before and after ESI. The correlations between the scores were estimated by calculating the difference between the baseline and follow-up scores. Of the 49 patients, 37 completed both questionnaire assessments. Among them, 26 patients (70%) presented a post-ESI decrease in scores obtained on all three scales. The NRS score decreased from 6.81±1.91 points at baseline to 3.66±2.22 points at follow-up (P<0.0001); similarly, the ODI score decreased from 41.65±14.76 to 30.38±16.16 points (P=0.0025); and the RMDQ score decreased from 11.11±5.68 to 7.64±5.74 points (P=0.011). Of the 37 patients who completed the two questionnaires, 26 had reduced NRS, ODI, and RMDQ scores. The intraclass correlation coefficients between the NRS and ODI, NRS and RMDQ, and ODI and RMDQ scores were 0.7943, 0.6615, and 0.7182, respectively. The concordance correlation coefficients between the NRS and ODI, NRS and RMDQ, and ODI and RMDQ scores were 0.6020, 0.4938, and 0.5202, respectively. Among the measurements, the correlation between the NRS and ODI scores was the highest, and a moderate correlation was found between the scores obtained using the other instruments.