• Journal of the Korean Geophysical Society
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• v.9 no.4
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• pp.361-369
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• 2006

This study conducted an initialization test to decide dynamic position using AHRS IMU sensor, and derived attitude correction angles of vehicles against time through regression analysis. It was also found that the heading angle was stabilized with variation less than 1°after 60 seconds. Using these angles, this study carried out an experiment on the determination of dynamic position for each system in the open sky and in a semi-open sky. According to the results, in the open sky, DGPS alone systems were excellent in accuracy but poor in data acquisition, so the moving distance was around 12m. In DGPS/IMU combined system, accuracy and data acquisition were satisfactory and the moving distance was around 0.3m. In a semi-open sky, DGPS alone systems were excellent in accuracy in order of DGPS < FIMU < DGPS/IMU according to average and standard errors obtained with exclusion of places where data were not be obtained. The moving distance was the same as that in the open sky. For DGPS, when places where data were not obtainable were divided into Several block and they were compared, the maximum deviation from the trajectory was up to 41.5m in DGPS alone system, but it was less than 2.2m and average and standard errors were significantly improved in the combined system. When the navigation system was applied to surveys and the result was compared with position error 0.2mm under the guideline for digital map, it was possible to work on maps on a scale of up to 1 : 1,000.

• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.1
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• pp.65-74
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• 2018

The aim of this study was to obtain the traceability of the software used to analyze lateral cephalometry and to calculate the uncertainty of the measurements. Furthermore, this study aimed to provide a basis for obtaining standard references for measurement values for orthodontic treatment in children. Cephalometric data were collected from 100 children diagnosed with class I malocclusion between the ages 6 to 13 years who visited the pediatric dentist at Seoul National University Dental Hospital. To ensure traceability, a phantom device was created. Correction values were calculated by measuring the length and angle of the phantom device using the software. Type A uncertainty was calculated by obtaining the standard deviation of cephalometric measurements of 100 persons and the standard error of repeated measurements. Determination of the type B uncertainty was induced by minimum resolution and the position of the head. Using these, the combined standard uncertainty was obtained and the expanded uncertainty was calculated. The results of this study confirm that the currently used software has high accuracy and reliability. Furthermore, the uncertainty of orthodontic measurements in Korean children aged 6 to 13 years was calculated, and distribution range for class I malocclusion with 95% confidence interval was suggested.

• Radiation Oncology Journal
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• v.26 no.2
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• pp.118-125
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• 2008

Purpose: On-line image guided radiation therapy(on-line IGRT) and(kV X-ray images or cone beam CT images) were obtained by an on-board imager(OBI) and cone beam CT(CBCT), respectively. The images were then compared with simulated images to evaluate the patient's setup and correct for deviations. The setup deviations between the simulated images(kV or CBCT images), were computed from 2D/2D match or 3D/3D match programs, respectively. We then investigated the correctness of the calculated deviations. Materials and Methods: After the simulation and treatment planning for the RANDO phantom, the phantom was positioned on the treatment table. The phantom setup process was performed with side wall lasers which standardized treatment setup of the phantom with the simulated images, after the establishment of tolerance limits for laser line thickness. After a known translation or rotation angle was applied to the phantom, the kV X-ray images and CBCT images were obtained. Next, 2D/2D match and 3D/3D match with simulation CT images were taken. Lastly, the results were analyzed for accuracy of positional correction. Results: In the case of the 2D/2D match using kV X-ray and simulation images, a setup correction within $0.06^{\circ}$ for rotation only, 1.8 mm for translation only, and 2.1 mm and $0.3^{\circ}$ for both rotation and translation, respectively, was possible. As for the 3D/3D match using CBCT images, a correction within $0.03^{\circ}$ for rotation only, 0.16 mm for translation only, and 1.5 mm for translation and $0.0^{\circ}$ for rotation, respectively, was possible. Conclusion: The use of OBI or CBCT for the on-line IGRT provides the ability to exactly reproduce the simulated images in the setup of a patient in the treatment room. The fast detection and correction of a patient's positional error is possible in two dimensions via kV X-ray images from OBI and in three dimensions via CBCT with a higher accuracy. Consequently, the on-line IGRT represents a promising and reliable treatment procedure.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.4
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• pp.519-525
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• 2014

Purpose: On this study, we investigated the relationship between the kinetic visual acuity (KVA) and the dynamic stereoacuity and the effects of anisometropia with measuring KVA and the dynamic stereoacuity. Methods: For 63 adults (male 30, female 33), KVA and the dynamic stereoacuity were measured by using the kinetic visual acuity tester (KOWA AS-4A) and the Howard-Dolman test (H-D test) at distance 2.5 m after conducted full correction of subjects' refractive error respectly. Results: The means of KVA were $0.49{\pm}0.25$ for total subjects, $0.58{\pm}0.26$ for male, $0.40{\pm}0.22$ for female, and LogMAD (Log minimum angle of displacement) dynamic stereoacuities were $1.27{\pm}0.44$($28.44{\pm}25.03sec$ of arc) for total subjects, $1.28{\pm}0.44$($28.23{\pm}23.34sec$ of arc) for male, $1.27{\pm}0.45$($28.63{\pm}26.83sec$ of arc) for female. KVA showed a statistically significant difference between male and female (p=0.00), but dynamic stereoacuity was no significant difference (p=0.97). No significant correlation was present between KVA and dynamic stereoacuity (r=0.03). Also there were no significant differences in the dynamic stereoacuity of the three group which were classified according to the low, middle, high range of KVA (p=0.99). The anisometropia were less than 1 D and over 1 D when divided into two groups, KVA and dynamic stereoacuity showed no significant difference between each (p=0.11, p=0.99). There was no significant correlation between anisometropia and KVA (r=0.33), dynamic stereoacuity (r=0.18) but the correlation between KVA and anisometropia revealed more higer than between dynamic stereoacuity and anisometropia. Conculsions: The KVA for adults showed a significant difference between male and female and male was higher than female for KVA. The dynamic stereoacuity due to the KVA, the KVA and dynamic stereoacuity due to anisometropia were not significant differences between each and also were not great correlations.