• Journal of Convergence for Information Technology
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• v.11 no.10
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• pp.20-26
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• 2021

In this paper, we studied the rotation angle estimation methods required for image alignment in an image recognition environment. In particular, a rotation angle estimation method applicable to a low specification embedded-based environment was proposed and compared with the existing method using complex moment. The proposed method estimates the rotation angle through similarity mathcing of the 1D projection profile along the radial axis after converting an image into polar coordinates. In addition, it is also possible to select a method of using vector sum of the projection profile, which more simplifies the calculation. Through experiments conducted on binary pattern images and gray-scale images, it was shown that the estimation error of the proposed method is not significantly different from that of complex moment-based method and requires less computation and system resources. For future expansion, a study on how to match the rotation center in gray-scale images will be needed.

• Journal of the Korea Society of Computer and Information
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• v.25 no.12
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• pp.73-82
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• 2020

Most process date such as semiconductor and petrochemical processes, autocorrelation often exists between observed data, but when the existing SPC(Statistical process control) is applied to these processes, it is not possible to effectively detect the average change of the process. In this paper, when the average change of a certain size occurs in the process data following a specific time series model, the average of the residuals changes according to the passage of time, and the change pattern of the average is introduced around the ARMA(1,1) process. Based on this result, the reference value required in the design process of the CUSUM (Cumulative sum) control chart is appropriately considered by considering the type of the time series model of the process data of the CUSUM control chart that can detect small mean changes in the process and the width of the process mean change of interest. It was confirmed through simulation that it should be selected and used.

• Imaging Science in Dentistry
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• v.53 no.2
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• pp.109-115
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• 2023

Purpose: The aim of this study was to evaluate changes in the trabecular bone through texture analysis and compare the texture analysis characteristics of different areas in patients with medication-related osteonecrosis of the jaw (MRONJ). Materials and Methods: Cone-beam computed tomographic images of 16 patients diagnosed with MRONJ were used. In sagittal images, 3 regions were chosen: active osteonecrosis(AO); intermediate tissue (IT), which presented a zone of apparently healthy tissue adjacent to the AO area; and healthy bone tissue (HT) (control area). Texture analysis was performed evaluating 7 parameters: secondary angular momentum, contrast, correlation, sum of squares, inverse moment of difference, sum of entropies, and entropy. Data were analyzed using the Kruskal-Wallis test with a significance level of 5%. Results: Comparing the areas of AO, IT, and HT, significant differences (P<0.05) were observed. The IT and AO area images showed higher values for parameters such as contrast, entropy, and secondary angular momentum than the HT area, indicating greater disorder in these tissues. Conclusion: Through texture analysis, changes in the bone pattern could be observed in areas of osteonecrosis. The texture analysis demonstrated that areas visually identified and classified as IT still had necrotic tissue, thereby increasing the accuracy of delimiting the real extension of MRONJ.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.1
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• pp.46-52
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• 2009

The purpose of this study was to compare the skeletal maturation of cervical vertebrae according to vertical skeletal patterns in the adolescents. Lateral cephalograms of 198 subjects(10 years old), 216 subjects(12 years old), and 138 subjects(14 years old) were reviewed, and subjects were classified according to vertical skeletal patterns. The 30 subjects were selected with the greatest predominance of vertical growth, and the other 30 subjects, with the greatest predominance of horizontal growth; these subjects comprised the vertical and horizontal groups, respectively. For evaluating of skeletal maturation, the concavity of inferior border and verticohorizontal ratio of cervical vertebrae were observed and measured according to age. The measurements were analyzed statistically by SPSS computerized program. The results were as follows : In general, the concavity of the inferior border of the cervical vertebrae was greater in the horizontal group than the vertical group in all of the 10, 12, 14 year olds, but was not statistically significant. The vertico-horizontal ratio of the 3rd and 4th vertebra of the horizontal groups was a significantly larger than the vertical groups in 12 year olds but did not show any statistical significance in 10 and 14 year olds. There were a weak negative correlations between SUM, FMA and the vertico-horizontal ratio for each groups at 12 ages.

• Journal of Ginseng Research
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• v.11 no.1
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• pp.32-38
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• 1987

Composition of free amino acids (FAA) in the central part (xylem plus piths,of tap root in P. ginseng was investigated in velation to stem status at harvest. The sum of FAA tended to be higher with dead stem than with healthy one but both were not significantly different. The sum of FAA (3.6-4.9% dried weight) was much less than total FAA, suggesting that water soluble nonprotein fraction contained large quantity of ninhydrih positive components except FAA. Pattern of amino acid composition between both stem status was not different. Ten of all 17 amino acids showed increasing tendency with dead stem and two, glutamic acid and cysteine, decreasing. Major FAA were arginine (relative content 58%), glycine (8.2), lysine (5.9), serine (5.7), glutamic acid (4.2) and aspartic acid (3.5). Above facts strongly suggest that the inside white of red ginseng did not closely related with FAA and that early defoliation or stem death did not decrease FAA. The content of arginine was heighest in all cases reported indicating the important role of nitrogen metabolism. Pattern of PAA composition except arginine was not different in present samples but greatly different with other cases reported mainly due to alanine, phenylalanine, glycine and proline.

• Journal of the Economic Geographical Society of Korea
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• v.20 no.3
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• pp.369-387
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• 2017

This research derived sum of light (SOL) for Liaoning and Dandong, China, from DMSP OLS satellite images acquired at nighttime during 1992 to 2012 and investigated its potential association with economic status. The SOLs of Liaoning were found to be continuously increasing and higher than those of averages for the other provinces across the time period. The temporal pattern of SOLs would be interpreted to well reflect the economic status of this region based on real growth rate and average wage per capita. Nevertheless, the SOLs of Dandong were lower than the average of the other prefecture-level cities, which indicated the economic status of this city in China. Meanwhile, the average annual growth rate of SOLs for Dandong turned out to be increase for 1998~2007, compared with the previous years, and temporal patterns in the trade amount between North Korea and China and the export amount of North Korea to China were similar to those of SOLs in the same time period. The political association between South and North Koreas was improved with 'Sunshine Policy' during 1997~2007. Taking it into account, SOL is expected to be valuable spatial proxy index that could explain the geopolitcal and geoeconomic aspects of Dandong.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.7
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• pp.683-693
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• 2011

In this paper, a design of high current and broad-band microwave bias-tee was presented for a stable bias of a high power amplifier. An input impedance of bias-tee should be shown to 50 ohm with the wideband in order to be stably-biased the amplifier. For this design of the bias-tee, a capacitor of bias-tee for a DC block was designed with a high wide-band admittance by a parallel sum of capacitors, and a inductor for a RF choke and a DC feeding was designed with a high wide-band impedance by a series sum of inductors. As this inductor and capacitor for the sum has each SRF, band-limitation of lumped element was driven from SRF. This limitation was overcome by control of a resonance's quality factor with adding a resistor. 1608 SMD chips for design's element was mounted on the this pattern for the designed bias-tee. The fabricated bias-tee presented 10 dB of return loss and wide-band about 50 ohm input impedance at 10 MHz~10 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.4
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• pp.318-327
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• 2017

It is essential for the near-field receiving measurement to make beam pattern and check the performance of a active phased array antenna system. Also, we could obtain compensation value for mono-pulse function through the near-field receive test, however, if the radar has many frequency channel, the test would take long time and hard effort. So it is needed that frequency channels are selected for measurement and calculates the values for other frequency channels to improve efficiency in development and manufacture. In this case, the phase variations in sum and del channels would be checked. The phase measurement includes un-linear characteristic because of wrapping effect. Generally, radars have similar path length in sum and del channel, but if a radar has a electrical length gap between sum and del channel, errors could occur by phase's wrapping effect. In this paper, the interpolation method's error caused by electrical length gap is checked and the effective method for frequency channel selection to avoid wrapping effect is introduced.

• Journal of Oriental Neuropsychiatry
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• v.34 no.3
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• pp.141-150
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• 2023

Objectives: This study aimed to comprehend the characteristics of Korean medicine patterns in relation to varying degrees of cognitive impairment in an elderly population. Methods: The dataset included 127 elderly individuals with cognitive impairment obtained from three Korean medicine hospitals between 2018 and 2021. The participants were categorized into two groups based on Clinical Dementia Rating-Sum of Boxes (CDR-SB) scores: those with questionable impairment (QI) and those with very mild dementia (VMD). A diagnostic framework for Korean medicine patterns encompassing Qi deficiency, Yin deficiency, Phlegm dampness, and Heat-fire was employed. Liver blood markers, including aspartate aminotransferase (AST), alanine aminotransferase (ALT), and the AST/ALT ratio, were also analyzed. Results: The scores of the cognitive assessment tools (MoCA-K, MMSE-DS, and K-IADL) of the QI group significantly differed from those of the VMD group. CDR-SB exhibited a positive correlation with the scores of each pattern of Qi deficiency, Yin deficiency, Phlegm dampness, and Heat-fire, whereas ALT and AST values displayed negative correlations. Binomial logistic analysis, controlling for potential confounders, such as age, education years, body mass index, the presence of chronic disease, and the presence of medication, verified that the VMD group showed higher pattern scores and lower ALT and AST values than the QI group. Conclusions: Increases in pattern scores along with decreased AST and ALT levels might be indicative of more severe cognitive impairment.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.11
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• pp.1088-1095
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• 2009

In this paper, we describe the reorientation method of distorted road sign by using projection transformation for improving recognition rate of road sign. RSR (Road Sign Recognition) is one of the most important topics for implementing driver assistance in intelligent transportation systems using pattern recognition and vision technology. The RS (Road Sign) includes direction of road or place name, and intersection for obtaining the road information. We acquire input images from mounted camera on vehicle. However, the road signs are often appeared with rotation, skew, and distortion by perspective camera. In order to obtain the correct road sign overcoming these problems, projection transformation is used to transform from 4 points of image coordinate to 4 points of world coordinate. The 4 vertices points are obtained using the trajectory as the distance from the mass center to the boundary of the object. Then, the candidate areas of road sign are transformed from distorted image by using homography transformation matrix. Internal information of reoriented road signs is segmented with arrow and the corresponding indicated place name. Arrow area is the largest labeled one. Also, the number of group of place names equals to that of arrow heads. Characters of the road sign are segmented by using vertical and horizontal histograms, and each character is recognized by using SAD (Sum of Absolute Difference). From the experiments, the proposed method has shown the higher recognition results than the image without reorientation.