• Journal of KIISE:Software and Applications
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• v.32 no.7
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• pp.612-624
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• 2005

In this paper, we propose a surface-based registration using a gaussian weighted distance map for PET-CT brain image fusion. Our method is composed of three main steps: the extraction of feature points, the generation of gaussian weighted distance map, and the measure of similarities based on weight. First, we segment head using the inverse region growing and remove noise segmented with head using region growing-based labeling in PET and CT images, respectively. And then, we extract the feature points of the head using sharpening filter. Second, a gaussian weighted distance map is generated from the feature points in CT images. Thus it leads feature points to robustly converge on the optimal location in a large geometrical displacement. Third, weight-based cross-correlation searches for the optimal location using a gaussian weighted distance map of CT images corresponding to the feature points extracted from PET images. In our experiment, we generate software phantom dataset for evaluating accuracy and robustness of our method, and use clinical dataset for computation time and visual inspection. The accuracy test is performed by evaluating root-mean-square-error using arbitrary transformed software phantom dataset. The robustness test is evaluated whether weight-based cross-correlation achieves maximum at optimal location in software phantom dataset with a large geometrical displacement and noise. Experimental results showed that our method gives more accuracy and robust convergence than the conventional surface-based registration.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.21-33
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• 2006

The reliability analysis can be conducted more effectively by formulating the stochastic finite element method suitable for the reliability theory about the cable stayed bridge. After conducting the initial equilibrium analysis of the cable stayed bridge, the program which can conduct the linear and nonlinear stochastic finite element analysis using the perturbation method and the reliability analysis considered to the correlation of the random variable is developed. Using the results of this program about the cable stayed bridge, the characteristic of the node displacement, element force and cable tension according to the correlation of the random variable is investigated quantitatively. Also the reliability index and the failure probability are examined by the compounding the correlation of the random variable.

• Journal of Biomedical Engineering Research
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• v.20 no.1
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• pp.29-36
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• 1999

The objective of this study is to analyse the flow field in the branching duct by visualizing the flow phenomena using the PIV system. A bifurcation model is fabricated with transparent acrylic resin to visualize the whole flow field with the PIV system. Water was used as the working fluid and the conifer powder as the tracer particles. The single-frame and two-frame methods of the PIV system and 2-frame of the grey level correlation method are applied to obtain the velocity vectors from the images captured in the flow filed. The velocity distributions in a lid-driven cavity flow are compared with the so-called standard experimental data, which was obtained from by 4-frame method in order to validate experimental results of the PIV measurements. The flow patterns of a Newtonian fluid in a branching duct were successfully visualized by using the PIV system and the sub-pixel and the area interpolation method were used to obtain the final velocity vectors. The velocity vectors obtained from the PIV system are in good agreement with the numerical results of the 3-dimensional branch flow. The results of numerical analyses and the PIV experiments for the three-dimensional flows in the branch ing duct show the recirculation zone distal to the branching point and the sizes of the recirculation length and height of the tow different methods are in good agreement.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4D
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• pp.687-693
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• 2006

Image co-registration is the process of overlaying two images of the same scene, one of which represents a reference image, while the other is geometrically transformed to the one. In order to improve efficiency and effectiveness of the co-registration approach, the author proposed a pre-qualified area matching algorithm which is composed of feature extraction with canny operator and area matching algorithm with cross correlation coefficient. For refining matching points, outlier detection using studentized residual was used and iteratively removes outliers at the level of three standard deviation. Throughout the pre-qualification and the refining processes, the computation time was significantly improved and the registration accuracy is enhanced. A prototype of the proposed algorithm was implemented and the performance test of 3 Landsat images of Korea. showed: (1) average RMSE error of the approach was 0.435 pixel; (2) the average number of matching points was over 25,573; (3) the average processing time was 4.2 min per image with a regular workstation equipped with a 3 GHz Intel Pentium 4 CPU and 1 Gbytes Ram. The proposed approach achieved robustness, full automation, and time efficiency.

• Journal of Food Hygiene and Safety
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• v.15 no.3
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• pp.252-255
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• 2000

This study was conducted to investigate the application of ATP bioluminescence to measure the degree of microbial contamination from raw meat, meat processing and milk processing lines. Samples collected from slaughter house, meat and milk processing plants were tested for estimation of bacterial number by using ATP bioluminescence and conventional method. The former result was transffered to R-mATP value(log RLU/ml), and the latter transffered to CFU(log/ml). Correlation coefficient(r) between aerobic counts(CFU, log/ml) and R-mATP(log RLU/ml) value was 0.93(n=408). R-mATP of aerobic counts from beef, pork, chicken was 0.93(n=220), and that was 0.93(n=187) between meat processing and dairy processing plants. In addition, Correlation coefficient(r) between aerobic counts and R-mATP was 0.87(n=252) under 1$\times$10${^5}$/ml of bacterial count and 0.74(n=152) over 10${^5}$ respectively.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.5
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• pp.484-493
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• 2012

Since the 1980s, there have been many research activities devoted to quantitatively characterizing and imaging human tissues based on sound speed, attenuation coefficient, density, nonlinear B/A parameter, etc., but those efforts have not yet reached the stage of commercialization. However, a new imaging technology termed elastography, which was proposed in the early 1980s, has recently been implemented in commercial clinical ultrasound scanners, and is now being used to diagnose prostates, breasts, thyroids, livers, blood vessels, etc., more quantitatively as a complementary adjunct modality to the conventional B-mode imaging. The purpose of this article is to introduce and review various elastographic algorithms for use in quasistatic or static compression type elasticity imaging modes. Most of the algorithms are based on the crosscorrelation or autocorrelation function methods, and the fundamental difference is that the time shift is estimated by changing the lag variable in the former, while it is directly obtained from the phase shift at a fixed lag in the latter.

• Journal of The Korean Association For Science Education
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• v.20 no.4
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• pp.542-561
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• 2000

The purpose of this study was to investigate the relationships among elementary school teachers' high school and college backgrounds in science, their attitudes toward teaching science, their science teaching efficacy beliefs, and their instructional strategies. Both quantitative and qualitative research methodologies, were utilized in this study. This paper, however, presents only the results of the quantitative data analysis while expecting to report the qualitative data analysis outcomes afterwards. Four instruments were used to ascertain information concerning teachers' backgrounds in science(the number of high school science courses they took and the grades of courses, the number of college science courses and grades, the number of college science methods courses and grades), attitudes toward teaching science, science teaching self-efficacy beliefs(personal science teaching efficacy and science teaching outcome expectancy), and their instructional strategies(indirect, direct, and mixed methods). A sample of 340 practicing elementary school teachers participated in this study. To determine statistically significant results, Pearson's correlation coefficient was used to relate teachers' backgrounds in science, attitudes toward teaching science, science teaching self-efficacy beliefs and their instructional strategies. The correlation coefficients were statistically significant regarding four variables, teachers' backgrounds in science, attitudes toward teaching science, science teaching self-efficacy beliefs, and instructional strategies investigated in this study. These results can be interpreted that programs of teacher preparations and trainings which include science and science methods courses should help prospective and practicing teachers change in their attitudes and beliefs toward science teaching. It is expected that future studies concerning teachers' attitudes, beliefs, and behaviors toward teaching science can help to improve science teacher education in Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.3
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• pp.163-172
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• 2006

Pot experiments were conducted from 1999 to 2001 to compare the different methods of available phosphorus (P) for estimation of biomass and P uptake by tomato and cucumber grown on different soils (25 soils for tomato and 8 soils for cucumber cultivation) collected from plastic film house of Chungbuk area. Supplementary experiment was conducted to estimate the relationship among several extraction methods of available P such as P adsorption, water extractable-P, Lancaster-P, Olsen-P, Bray No 1 and No 2-P, and Mehlich 1 and 3-P for a total of 71 soils that included 33 soils collected for tomato and cucumber cultivation and 38 soils taken from other sites of plastic film house. All the extraction methods of available phosphorus except P adsorption were mutually positive correlated with r ranging from 0.81 to 0.96 while the correlation coefficient between P adsorption and other methods ranged from -0.57 to -0.80. Phosphorus uptake by tomato plant applied with no fertilizer was significantly correlated with the available P extracted by different methods except P adsorption in all the experiments showing positive correlation coefficients from 0.49 to 0.76 in April, 1999, 0.53 to 0.71 in April, 2000, and 0.59 to 0.68 in October, 2000. Consequently relative amount of P uptake by tomato plant for all the experiments also significantly correlated with available P in soils showing correlation coefficients of r=0.64~0.73 (P<0.0000001) in the order of Mehlich 1-P > Mehlich 3-P > Lancaster-P. For tomato, critical concentrations of available P in soils estimated by Cate and Nelson split method were $1700mg\;kg^{-1}$ for Mehlich 3-P, $1,050mg\;kg^{-1}$ for Mehlich 1-P, and $95mg\;kg^{-1}$ for water extractable P. Also P uptake by cucumber plant was significantly correlated with Olsen-P, water extractable P, and Bray No 2-P with r value of 0.62, 0.59, and 0.51, respectively, in soils of no fertilization.

• Journal of the Korean Geophysical Society
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• v.6 no.1
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• pp.31-38
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• 2003

Multi-channel seismic survey, which has been mainly employed in oil prospecting, is carried out as a high resolution shallow marine seismic exploration. Fault drop as small as 1 m can be resolved by employing high-resolution seismic survey. Similar to the effect of shallow inhomogenities in the land seismic data, due to occurrence of swell quite often higher than 1 m, shallow marine seismic data tend to be severely degraded. Suppression of such a swell effect is critical in processing of steps of marine seismic shallow high-resolution data. Compared to the moving average depth method, a newly developed method using cross-correlation technique is found out to be very effective in increasing the resolution of the shallow reflection events by accuratly elucidating the depth of sea bottom.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.5
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• pp.595-600
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• 2014

Nowadays our society is rapidly transforming into an aging society. A better understanding of dementia is a high priority in the aging society. Therefore our study is basically aimed at understanding characteristics of EEG signals from dementia patients. Firstly, we analyzed spontaneous EEG signals from normal persons and dementia patients to distinguish their characteristics. The EEG signals are recorded with 16 electrodes and we classified the EEG signals form the signals according to frequency band. To obtain the clean EEG signals, we used cross correlation function between two channels. From the analysis results, we can observe that the EEG characteristics from dementia patients are distinctly different from that from normal persons.