• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.5
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• pp.466-471
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• 2011

Optical coherence tomography(OCT) is an emerging medical diagnostic tool that draws great attention in medical and biological fields. It has a 10-100 times higher spatial resolution than that of the clinical ultrasound but lower imaging depth such as 1-2 mm. In order to image internal organs, OCT needs an endoscopic probe. In this paper, the principle of Fourier-domain optical coherence tomography with high-speed imaging capability was introduced. An OCT endoscope based on MEMS technology was developed. It was attached to the Fourier-domain OCT system to acquire three-dimensional tomographic images of gastrointestinal tract of New Zealand white rabbit. The endoscope had a two-axis scanning mirror that was driven by electrostatic force. The mirror stirred an incident light to sweep two-dimensional plane by scanning. The outer diameter of the endoscope was 6 mm and the mirror diameter was 1.2 mm. A three-dimensional image rendered by 200 two-dimensional tomographs with $200{\times}500$ pixels was displayed within 3.5 seconds. The spatial resolution of the OCT system was 8 ${\mu}m$ in air.

• Journal of the Korean Society of Radiology
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• v.9 no.1
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• pp.31-37
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• 2015

The cases of radiographic inspection for medical diagnosis in Korea have been continuously increasing year after year, which pays particularly more attention to CT which occupies over the half of medical radiation exposure. To find an effective alternative for reducing radiation exposure, the researchers conducted comparative experiments using some shields made of bismuth, aluminum 6mm, and silicone 22mm. These shielding materials have been used to reduce the entrance surface dose (ESD) on lenses, maintaining the CT number, noise, and uniformity in brain CT scanning which forms the largest part in CT scanning these days. These experiments showed that the doses in the spiral scan parallel to IOML and the conventional scan in Bismuth were 26.41% and 17.52%, respectively; in Aluminum 18.24% and 9.39%; in Silicone 19.47% and 14.39% lower than compared with those in the cases without any shields. In the items of the CT number, noise, and uniformity, the bismuth shield satisfied exceedingly the standards of the phantom image test while aluminum and silicone were within. To keep the graphic quality and get good shielding effect, we recommend the silicone shield which can be manufactured and purchased with ease.

• Journal of the Korean Society of Radiology
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• v.13 no.7
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• pp.1015-1024
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• 2019

In the medical field, X-rays are essential in the diagnosis and treatment of diseases, and the use of X-rays continues to increase with the development of imaging technology, but X-rays have the disadvantage of radiation exposure. Although lead protection tools are used in clinical practice to protect against radiation exposure, lead is classified as a heavy metal and can cause harmful reactions such as lead poisoning. Therefore, the purpose of this study is to investigate the usefulness of the shield fabricated using materials of FDM (Fused Deposition Modeling) 3D printer. In order to confirm the filament's line attenuation factor, phantoms were fabricated using PLA, XT-CF20, Wood, Glow and Brass, and CT scan was performed. And the shielding sheet of 100 × 100 × 2 mm size was modeled, the dose and shielding rate was measured by using a diagnostic X-ray generator and irradiation dose meter, and the shielding rate with lead protection tools. As a result of the experiment, the CT number of the brass was measured to be the highest, and the shielding sheet was manufactured by using the brass. As a result of confirming with the diagnostic X-ray generator, the shielding rate was increased in the shielding sheet having a thickness of 6 mm upon X-ray irradiation under the condition of 100 kV and 40 mAs. It measured by 90% or more, and confirmed that the shielding rate is higher than apron 0.25 mmPb. As a result of this study, it was confirmed that the shield fabricated by 3D printing technology showed high shielding rate in the diagnostic X-ray region. there was.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.4
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• pp.229-240
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• 2019

3D geo-spatial model have been widely used in the field of Civil Engineering, Medical, Computer Graphics, Urban Management and many other. Especially, the demand for high quality 3D spatial information such as precise road map construction has explosively increased, MMS and UAV techniques have been actively used to acquire them more easily and conveniently in surveying and geo-spatial field. However, in order to perform 3D modeling by integrating the two data set from MMS and UAV, its so needed an proper registration method is required to efficiently correct the difference between the raw data acquisition sensor, the point cloud data generation method, and the observation accuracy occurred when the two techniques are applied. In this study, we obtained UAV point colud data in Yeouido area as the study area in order to determine the automatic registration performance between MMS and UAV point cloud data using ICP(Iterative Closet Point) method. MMS observations was then performed in the study area by dividing 4 zones according to the level of overlap ratio and observation noise with based on UAV data. After we manually registered the MMS data to the UAV data, then compared the results which automatic registered using ICP method. In conclusion, the higher the overlap ratio and the lower the noise level, can bring the more accurate results in the automatic registration using ICP method.

• Journal of dental hygiene science
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• v.14 no.2
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• pp.230-239
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• 2014

This study is to promote awareness to be exposed to radiation with identifying knowledge, attitudes and behavior for radiation safety management of the operating room nurse and dental hygienist. And the following results were obtained through questionnaire survey to deduct the education to prevent potential risks in advance and implication to be useful on education program. First, based on the level of knowledge for radiation safety management, 10.57 for dental hygienists, 9.55 for the nurse out of 15 points (p<0.001); based on the level of attitudes for radiation safety management, 4.64 for dental hygienists, 4.67 for the nurse out of 5 points (p<0.001); and based on the level of behavior for radiation safety management, 3.27 for dental hygienists, 2.93 for the nurse out of 5 points (p<0.001). Second, the result for checking the relation with knowledge, attitudes and behavior for radiation safety management, the knowledge of radiation safety management has correlation with attitudes and behavior for radiation safety management statistically (p<0.001).

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.3
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• pp.194-201
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• 2014

This paper is able to be solved by improving degradation in multi-path environment by adjust beam pattern angle through modifying pulse phase of each antennas by using TRM (Transmitter Receiver Module). Beam Scanning Array Antenna, which is transmitter/receiver that improves degradation in multi-path environment without any signal distortion, is designed and manufactured. Beam Scanning Array Antenna should be able to send/receive signal at the antenna's longitudinal part without distortion and should not influences other systems. Also, it should include target detecting ability by beam steering.Dispersion characteristic of Beam Scanning Antenna, which is designed, is analysed by using fidelity, and steering and radar resolution performance is verified by using $1cm{\times}1cm$ sized target. To manufacture Beam Scanning Array Antenna, control board and GUI, which is able to control Vivaldi Antenna for IR-UWB, Tri-Band Wilkinson power divider, and TRM (Transmitter Receiver Module), is designed. Throughout this research, developed Beam Scanning UWB Array Antenna system is adoptable for radar application field. and time domain analysis techniques by using network analyser made the antenna characteristics analysis for setting up antenna more accurate. In addition, it makes beam width checking without difficulties.

• Progress in Medical Physics
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• v.20 no.3
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• pp.159-166
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• 2009

Obviously, the administration of the prescribed amount of activity to the patient requires proper operation of the dose calibrator, which shall be verified by implementing the required quality control on the instrument. This investigation examined the accuracy and precision of dose calibrator activity measurement of the radiopharmaceutical F-18 FDG. To investigate the status of the nuclear medicine centers in Korea for the performance of dose calibrators, 10 centers providing PET/CT system services in Korea were inspected in 2008. We measured accuracy and precision in 10 equipments in consideration of PET/CT model, installation area, and installation time. According to the results of comparative analysis of 10 dose calibrators used to measure radioactivity of F-18 FDG, accuracy was -5.00~4.50% and precision was 0.05~0.45%, satisfying the international standards, which are accuracy ${\pm}$10% and precision ${\pm}$5%. This study demonstrated that, for accurate measurements, no adjustment is necessary for a dose calibrator setting when measuring different dose calibrators of F-18 FDG activity prescriptions.

• Journal of the Korean Magnetics Society
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• v.25 no.2
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• pp.52-57
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• 2015

The focal spot of electron beam depending on the anode angle in the structure and major parts of the X-ray tube was investigated by the OPERA-3D/SCALAR simulation program. The simulation worked on four spaces with with two spaces, including anode and cathode of X-ray tube, by applying the finite element method analysis. The analytical model and dimension for the emission orbit of thermal electrons made from one filament of the focused X-ray cathode is affected to the penumbra of detector for the X-ray depending on any real focal spot size. The model shape of focusing cap and focusing tube with an anode target angle and a cathode filament is analyzed by the current density distribution of thermal electrons. The focusing width of thermal electrons for the X-ray tube depended on the anode angle (${\theta}$). The focusing value of electron beams at a region of anode angle having $10^{\circ}{\sim}17^{\circ}$ maintained to below value of $70{\mu}m$. The minimum focal size of the electron beam was $40{\mu}m$ at an anode angle of $15^{\circ}$. The focused X-ray tube of many variables depended on the thermionic emission of hot electrons from the target trajectory. The focusing tube will contribute to the real design of X-ray for the development of future diagnosis medical device.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.579-587
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• 2017

Although interventional procedures use very low tube currents, there is a high risk of exposure to radiation as well as the operator due to long-term radiation exposure. The purpose of this study is to investigate the effects of radiation dose on the quality of the operator by measuring the dose received by the operator in the interventional procedure of the cerebral vascular system and finding the shielding material and shielding method which can effectively shield the exposure from the medical radiation. And to find a way to minimize it to the extent that it does not. As a result, when the newly designed shielding system with Nano Tungsten material was used, it was confirmed that the mean dose was reduced by 7.95% on average by the operator. Also, the PSNR results were measured to be 38.44 dB when using the designed shielding material, and it was confirmed that Nano Tungsten does not affect the image quality. In conclusion, the Nano Tungsten shielding material proved to be capable of significantly reducing the operator radiation dose, without affecting the image quality. The use of the above materials is expected to solve the problems related to the harmfulness and economical efficiency of the human body and the environment, which have recently become an issue of shielding materials.

• Journal of Korea Multimedia Society
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• v.11 no.9
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• pp.1204-1212
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• 2008

The vehicle simulation (flight simulator) in 1920's was the first in the virtual reality. With the development of precise optical and electromagnetic equipment, the virtual reality widened its application for other purposes than military one. Based on the realistic display technology, it is more and more common in the various areas such as entertainment, medical profession, learning, film, architectural design, tourism and etc. In 1989, Jaron Ranier was the first to use the terminology 'Virtual Reality'. With this term, all virtual projects could be classified in a single item. But even before the term was used, the virtual reality has been studied up to now. As a part of virtual reality, the human thirst for the impossible thing has led to the development of ride film. The ride film consists of the special technical elements as well as the psychological analysis of human being. The ultimate purpose of virtual reality is engrossment through interaction. Even though the real interaction requires interface, input sensor and reaction ability, the ride film is not an element of the typical interaction. The virtual reality is mostly defined in technical terms now. But in this study, we will analyze the concepts worked out by Professor Michael Haim who is called a philosopher in the cyberspace in aspect of experience-oriented definition. We will analyze the adaptability of virtual reality based on his concepts such as artificial reality/ interaction/ engrossment/ networked world/ remote display/ simulation/ onmon engrossment. And also, we aim to suggest the directions of developing the ride films for perfect engrossment and to draw optimized conclusion thereon. In this viewpoint, we consider that the study of ride film on which there were few case studies will contribute to level up the basic frameworks of IT technology and the digital image.