• Journal of the Korea Convergence Society
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• v.11 no.5
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• pp.209-217
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• 2020

The background of the research is the following. With the prosperity of drone industry, the government has been actively promoting measures to nominate 'drone photographing free areas'. However, existing laws, and procedures are rather unclear with related environmental factors in discordance with one another. Hence, voices in need for establishing a clear precondition for nominating drone photography free area have been rising. The purpose of the research is to provide measures for the preconditions to establish photography free areas for convenient drone photographing. The research utilizes literary methods, conducting focus group interviews to coordinate with specialists who can participate and discuss so that they can provide improvement measures. The research renders improvement measures in different sectors including 2x items in aviation security law, 8x items in free area nomination and procedure, 4x items in infrastructure establishment and information management area. The expected effects are the following: by attaching drone photography with aviation security law, nominating photography free area can be linked up with the Ministry of Land Infrastructure and Technology. Secondly, by enlarging photography restricted area to upper mid-air, a three dimensional drone security will be possible. Thirdly, by providing a 'Yongin area standard model', free area nomination will become more easy. Future research will focus on enhancing aviation security law regarding drone photographing. In addition, the promotion to nominate free areas for 33x responsible areas in accordance with the National Intelligence service will be required.

• Journal of radiological science and technology
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• v.32 no.4
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• pp.393-399
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• 2009

In this study, we measured the dose distribution of scattered ray in X-ray radiography room using an ion chamber and examined the dependency of scattered ray content on the scattered ray source and exposure condition. To study the factors of scattered ray occurrence in the acryl phantom, we measured the change in the scatted ray content according to the X-ray tube voltage (40~140 kV) and the field size ($10{\times}10\;cm^2$, $20{\times}20\;cm^2$, $35{\times}35\;cm^2$). For the $35{\times}35\;cm^2$ field size, the side-scattering rate ranged from 3.1% to 14.5%. The scattered ray contributions of the phantom, collimator, X-ray tube and wall were also measured. The scattered ray contribution of the phantom was higher than 95.4% for the entire tube voltage, and those of the collimator, X-ray tube and wall were 2.6%, 1.3% and 0.7%, respectively.

• Composites Research
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• v.30 no.6
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• pp.393-398
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• 2017

The shrinkage distribution of a dental composite (Clearfil AP-X, Kuraray, Japan) used for dental restoration was observed using a digital image correlation method. In order to analyze the shrinkage distribution formed during and after light irradiation, digital images were taken with different photographing conditions for each period. Optimal photographing conditions during LED irradiation were obtained through a preliminary experiment in which the exposure time was applied from 0.15 ms to 0.55 ms in 0.05 ms intervals. The DIC analysis results showed that the strain was non-uniform. For the initial 20 s of light irradiation the composite resin shrank to the level of 50~60% of the final curing shrinkage. Such large shrinkage amount of the composite resin lump affected the tensile stress concentration near the adhesive region between the composite resin and the substrate.

• Smart Media Journal
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• v.5 no.1
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• pp.44-48
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• 2016

In a longitudinal neuroimaging study, the upgrades of a magnetic resonance imaging (MRI) scanner due to outdated hardwares and softwares make it difficult to maintain the same MRI conditions in the long-term research period. Particularly, high field MRI systems such 3T scanners become popular in recent years. However, it is still unclear whether an integrated analysis of 3T and 1.5T images is possible without consideration of the field strength. In this study, we evaluated the reproducibility of hippocampal volumes between brain images with different field strengths and slice orientations. 296 participants underwent both 3T and 1.5T MRI and both sagittal and axial scans for high resolution brain images, and their hippocampal volumes were measured using Freesurfer, a well-known software for neuroimaging analysis. Paired t-tests showed that the hippocampal volumes were significantly different between the image types. These results suggest that it is necessary to develop data analysis techniques for integrating diverse types of MRI images.

• Journal of the Korean Society of Radiology
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• v.11 no.2
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• pp.79-85
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• 2017

The purpose of this study is to investigate the cause analysis according to the difference between the pre exposure tube voltage and actual exposure tube voltage in mammography in connection with breast pressure thickness, breast size and body mass index and to find the improvement. The study tracked 377 women age 40 and older among the mammography examiners conducted by the National Health Insurance Corporation. It was analyzed that breast pressure thickness, breast size and body mass index according to the difference between the pre exposure tube voltage and actual exposure tube voltage among the parameters of dose report been sent to the picture archiving communication system with reference to the image with cranio-caudal projection in mammography. As are result, it shows that the thicker the breast thickness, smaller the breast size and lower body mass index, the higher the difference of tube voltage. In conclusion, the minimum tube voltage of mammography machine should be reset in order to set the tube voltage according to breast pressure thickness and breast size that are suitable for our country in mammography, in addition, it was considered that radiologist should make an effort to reduce radiation exposure and make a good quality image with reducing the difference of mammography condition by making a correct exposure condition in case of examining the patients with thin breast pressure and small breast size.

• Korean Journal of Remote Sensing
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• v.28 no.4
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• pp.459-466
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• 2012

Satellite operation is divided as user's request, image collection planning, product generation, distribution. Image collection planning is to make image collection plan of satellite to reflect user's request in proper time based on NTO (New Task Order) and AO (Archive Order) using limited satellite resources. Image collection planning has high computational cost because of considering several variables simultaneously, is to be performed identical process repeatedly. In this paper, optimization research of image collection planning is performed for efficient planning. First, formulation of image collection planning is made to require satellite image as much as possible and then Heuristic algorithm is suggested for solution of formulation.

• Journal of Digital Convergence
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• v.16 no.12
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• pp.441-447
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• 2018

This study aims to develop digital techniques that enable repeated practice of dental radiography using augmented reality technology. A three-dimensional object was fabricated by superimposing a photograph of an adult model and a computed tomography image of a manikin phantom. The system was structured using 106 radiographs such that one of these saved radiographs is opened when the user attempts to take a radiograph on a mobile device. This system enabled users to repeatedly practice at the pre-clinical stage without exposure to radiation. We attempt to contribute to enhancing dental hygienists' competency in dental radiography using these techniques. However, a system that enables the user to actually take a radiograph based on face recognition would be more useful in terms of practice, so additional studies are needed on the topic.

• Proceedings of the Korean Society of Radiological Science
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• 1992.10a
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• pp.113-114
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• 1992

• Proceedings of the Korean Society of Radiological Science
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• 1997.05a
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• pp.95.3-96
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• 1997

• Proceedings of the Korean Society of Radiological Science
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• 1992.05a
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• pp.15-16
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• 1992