• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.4
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• pp.123-128
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• 2020

Technology in digital video has changed the functions of the digital video field based on various platforms, including streaming, on-demand, interactive, and data-based services. The displays that provide the visual representations of these digital video contents have also been improving with various changes. There is a variety of display screen ratios currently available, with the ratio of the display screen being based on the intended purpose. This study conducted a psychophysics experiment to examine the correlation between colour properties and shape ratio based on the display screen ratio, and then analysed the results. The colours used in the experiment were visual perception-based Munsell colours, and the hue, brightness, and chroma attributes were analysed according to the shape ratio to examine colour properties. The analysis of the results of this study defined the significance of the study as basic data for future studies on colour property changes based on shape ratio, and suggested directions for future studies.

• Progress in Medical Physics
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• v.23 no.4
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• pp.292-302
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• 2012

The patient dose in advanced radiotherapy techniques is an important issue. These methods should be evaluated to reduce the dose in diagnostic imaging for radiotherapy. Especially, the Computed Tomography in radiotherapy has been used widely; hence the CT was evaluated for dose and image in this study. The evaluations for dose and image were done in equal condition due to compare the dose and image simultaneously. Furthermore, the possibility of dose and image evaluations by using the Monte Carlo simulation MCNPX was confirmed. We made the iterative reconstruction for low dose CT image to elevate image quality with Maximum Likelihood Expectation Maximization; MLEM. The system we developed is expected to be used not only to reduce the patient dose in radiotherapy, also to evaluate the overall factors of image modalities in industrial research.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.3
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• pp.261-266
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• 2019

Flow cytometry is an electrical detection system that provides precise and diverse optical properties to cells and micro particles. Flow cytometry, which provides multidimensional information including cell size and granularity through light scattering and fluorescence emission generated by the induction of light of a specific wavelength to the fluorescently treated cells or micro particles, plays an important role in biomedical and biophysical fields. However, it has some drawbacks such as high cost, size of the instrument and limitation in selecting fluorescent dyes. Therefore, in this paper, a low cost compact fluorescent detection system is developed using light-emitting diode and microcontroller. The proposed fluorescence detection system has a replaceable the light source/fluorescence filter/photodetector and constructed by 3D printer, so that the user can design a customized system according to the selected fluorescent dyes. The fluorescence intensity was measured by varying the number of fluorescently labeled cells, and the measured intensities showed a high linearity within the tested concentration ranges.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.3
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• pp.65-70
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• 2023

In recent years, the digital media environment has begun to diversify, with a greater focus being placed on user-centric design. With the development of digital technology, the digital media environment has formed a vast network of information, which supports interactive communication between people, creating a need for user-centric research. Mobile displays, as a representation of the digital media environment, have the advantage of mobility through the use of thin screen displays and low-performance image sensors, which allow for miniaturization and power saving. However, this results in reduced colour accuracy compared to large displays. This study investigates users' colour perception when using dark and light mode mobile displays. Colour perception was measured using a psycho-physical experiment, which controls each colour attribute based on the 12 colours of KS. The results were analysed to determine whether there is a difference in colour perception between dark mode and light mode, and if the difference was statistically significant. Future research directions based on the results are then discussed.

• Journal of the Korea Computer Graphics Society
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• v.29 no.3
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• pp.149-158
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• 2023

HMD, which is applied with the latest technology, minimizes motion sickness with high-resolution displays and fast motion recognition, and can accurately track location and motion. This can provide an environment where you can immerse yourself in a virtual three-dimensional space, and virtual reality contents such as disaster simulators and high-risk equipment learning spaces are developing using these characteristics. These advantages are also applicable in the field of basic science education. In particular, expanding the concepts of electric and magnetic fields in physics described by existing two-dimensional data into three-dimensional spaces and visualizing them in real time can greatly help improve learning understanding. In this paper, realistic physical education environments and contents based on three-dimensional virtual reality are developed and the developed learning contents are experienced by actual learning subjects to prove their effectiveness. A total of 46 middle school and college students were taught and experienced in real time the electric and magnetic fields expressed in three dimensions in a virtual reality environment. As a result of the survey, more than 85% of positive responses were obtained, and positive results were obtained that three-dimensional virtual space-based physical learning could be effectively applied.

• Analytical Science and Technology
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• v.20 no.6
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• pp.508-515
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• 2007

Age determination was carried out with the bricks relating to Muryong Royal Tomb of the Baekje Kingdom, for which there is no information on the external gamma dose rate, by using the subtraction method of luminescence dating. In the subtraction method, each paleodose for fine grain and for quartz inclusion is required for the sample to be dated. In this study, the paleodose for the fine grain was estimated by thermoluminescence measurement and the paleodose for the quartz inclusion was determined using optically stimulated luminescence. The resultant ages among the bricks showed good agreement with standard deviation of 6 % error. Finally the bricks relating to Muryong Royal Tomb were evaluated as AD $530{\pm}50yrs$($1{\sigma}$ SD).

• Progress in Medical Physics
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• v.13 no.1
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• pp.32-36
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• 2002

For Intensity Modulated Radiation Therapy(IMRT), the spatial resolution of intensity map(IM) is limited by the width of multi-leaf collimator, which would make an effect on the conformity of the target, as well as organs at risk. Several Methods are suggested to increase the spatial resolution, which can be categorized by the hardware-dependent technique and the software-based technique. However the best solution might be to make the width of MLC finer. it has several obstacles in the respects of technical difficulty and cost. This preliminary study is designed to investigate the clinical effectiveness of the virtual-micro IMRT(VMIMRT) technique, one of the software-based technique. A particular intensity map was created, which has 42$\times$54 pixel dimension ,0.5cm pixel size and 15 intensity levels. Using this intensity map, segment fields of IMRT were generated with 1$\times$lcm, 0.5$\times$1cm, 0.5$\times$0.5cm(VMIM) beamlet size, respectively As results, we found that there was no evidence of improvement for VMIMRT, compared with the 0.5$\times$lcm beamlet size which can be delivered by 1cm width MLC. The reason seems to be due to the constraint of VMIMRT. Further study is required to prove the benefit of the VIMRT in clinical case like head and neck cancer, where is expected that higher resolution than 1cm is necessary.

• Bulletin of the Korean Space Science Society
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• 2007.10a
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• pp.139-143
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• 2007

Electric propulsion has become a cost effective and sound engineering solution for many space applications. The success of SMART-1 and MUSES-C developed by European Space Agency (ESA) and Japan Aerospace Exploration Agency (JAXA) each proved that even small spacecraft could accomplish planetary mission with electric propulsion systems. A small electric propulsion system which is Hall effect thruster like SMART-1 is under development by SaTReC and GDPL (Glow Discharge Plasma Lab.) in KAIST for the next microsatellite, STSAT-3. To achieve optimized propulsion system, it is very necessary to understand plasma motions of Hall effect thruster. In this paper, we try to approach comprehensive plasma model with the particle simulation complementary to Particle In Cell (PIC) simulation. We think these two different approaches will help experimenters to optimize Hall effect thruster performances.

• Journal of The Korean Association For Science Education
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• v.39 no.4
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• pp.563-571
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• 2019

The purpose of this study is to analyze the safety contents presented in high school science textbooks of the 2015 revised national science curriculum. For these, we found safety contents in the inquiries and appendices of 63 science textbooks: integrated science, science inquiry experiment, physics I, II, chemistry I, II, biology I, II, and earth science I, II. We analyzed these safety contents using six safety factors based on the seven standards for safety education. The main results are as follows: First, 81(46.0%) inquiries among 176 curriculum inquiries contain safety contents, and these contents are mainly found in chemistry textbooks, and the least in 'science inquiry experiment' textbooks. Second, safety contents are found the most in 'laboratory safety rule', followed by 'safety symbol' and 'usage of protection equipment'. Third, the safety contents of appendices are mainly in 'laboratory safety rule' and 'accident treatment'. Based on these results of this study, it is concluded that these textbooks have problems; that there is a big difference in describing safety contents in each textbook; that these safety contents are not presented in detail and that the educational effect is reduced. Furthermore, the safety symbol is not standardized. We also discussed ways to improve the safety contents of science textbooks.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.3
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• pp.83-90
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• 2019

In this paper, Mg-doped AlN epilayers for power semiconductor devices are grown by mixed-source hydride vapor phase epitaxy. Magnesium is used as p-type dopant material in the grown AlN epilayer. The AlN epilayers on the GaN-templated sapphire substrate and GaN-templated-patterned sapphire substrate (PSS), respectively, as the base substrates for device application, were selectively grown. The surface and the crystal structures of the AlN epilayers were investigated by field emission scanning electron microscopy (FE-SEM) and high-resolution-X-ray diffraction (HR-XRD). From the X-ray photoelectron spectroscopy (XPS) and Raman spectra results, the p-type AlN epilayers grown by using the mixed-source HVPE method could be applied to power devices.