• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.2 s.302
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• pp.69-80
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• 2005

In these days, the technology development of the imaging/optic industry and the digital broadcasting replace the classic CRT with the new display devices that is getting slimmer and larger. Especially, when the general TV signal is applied directly to the wide gamut display using LED or laser, which can display higher chromatic colors that can't be reproduced on CRT, the color distortion occurs and it causes serious problems. Thus, in this paper the gamut mapping is studied, which gets rids of the color distortion and utilizes the wider color gamut than that of the CRT sufficiently. In the gamut mapping the general mapping concept is the increasement of the chroma on the same hue plane but it causes the over chromatic enhancement. So, the vector mapping, which increases the lightness md the chroma at the same time, is proposed to prevent the side effect. In the vector mapping the chromaticity is maintained constantly, hence the image can be seen more natural than that of the chroma mapping. By using the gamut fitting, it is compensated that the tone disappearance or the contour effect that is arose from the geometric properties of the input and the output color gamut. These gamut mapping and gamut fitting can prevent the color distortion and reproduce the natural image on the wide gamut displays.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.2
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• pp.39-48
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• 2015

Lately, Unmanned Aerial Vehicles(UAV), Unmanned Aerial Systems(UAS) or also often known as drones, as a data acquisition platform and as a measurement instrument are becoming attractive for many photogrammetric surveying applications, especially generation of the high density point clouds(HDPC). This paper presents the performance evaluation of a low-cost rotary wing quadrocopter UAS for generation of the HDPC in a test bed environment. Its performance was assessed by comparing the coordinates of UAS based HDPC to the results of Network RTK GNSS surveying with 62 ground check points. The results indicate that the position RMSE of the check points are ${\sigma}_H={\pm}0.102m$ in Horizonatal plane, and ${\sigma}_V={\pm}0.209m$ in vertical, and the maxium deviation of Elevation was 0.570m within block area of ortho-photo mosaic. Therefore the required level of accuracy at NGII for production of ortho-images mosaic at a scale of 1:1000 was reached, UAS based imagery was found to make use of it to update scale 1:1000 map. And also, since this results are less than or equal to the required level in working rule agreement for airborne laser scanning surveying of NGII for Digital Elevation Model generation of grids $1m{\times}1m$ and 1:1000 scale, could be applied with production of topographic map and ortho-image mosaic at a scale of 1:1000~1:2500 over small-scale areas.

• Journal of radiological science and technology
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• v.40 no.4
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• pp.621-626
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• 2017

In this paper, an optical dosimetric system for radiation dose measurement is developed and characterized for 100 MeV proton beams in KOMAC(Korea Multi-Purpose Accelerator Complex). The system consists of 10 wt% Ultima GoldTM liquid organic scintillator in the ethanol, a camera lens(50 mm / f1.8), and a high sensitivity CMOS(complementary metal-oxide-semiconductor) camera (ASI120MM, ZWO Co.). The FOV(field of view) of the system is designed to be 150 mm at a distance of 2 m. This system showed sufficient linearity in the range of 1~40 Gy for the 100 MeV proton beams in KOMAC. We also successfully got the percentage depth dose and the isodose curves of the 100 MeV proton beams from the captured images. Because the solvent is not a human tissue equivalent material, we can not directly measure the absorbed dose of the human body. Through this study, we have established the optical dosimetric procedure and propose a new volume dose assessment method.

• Korean Journal of Microbiology
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• v.50 no.3
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• pp.233-238
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• 2014

For the collection of starters suitable for the brewing of traditional liquor, an alcohol-resistant strain of lactic acid bacteria with low level of acid production was isolated from traditional fermented soybean lumps. The strain named as JBE 30 was identified as Lactobacillus brevis by 16S rRNA sequence analysis and additional biochemical tests. The strain could grow well at a MRS medium containing 8% (v/v) ethanol for 96 h of cultivation at $30^{\circ}C$. The final pH after cultivation was 4.5. It also inhibited the growth of food spoilage and pathogenic bacteria including Escherichia coli, Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Micrococcus luteus, and Pseudomonas aeruginosa. These results showed that Lactobacillus brevis JBE 30 could be used as a promising starter in brewing process of traditional liquor.

• Progress in Medical Physics
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• v.8 no.2
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• pp.35-43
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• 1997

The knowledge of x-ray spectra is highly desirable in some investigation involves the differential penetrating power and absorption coefficient correction of various photon beam. The transmission data were obtained from the 80 kVp and 120 kVp of CT x-ray beam with the aluminium filter which is designed in a 30 cm of diameter and pipe-typed filter was prepared from 5.0 mm upto 92.3 mm of thickness. To obtain the reconstructed spectra of CT x-ray, the investigator used the iterative numerical analysis which has been extended to include the tungsten characteristics from experimental transmission data with energy interval of 2 keV. Comparison of the calculated transmission data from the reconstructed spectra with that of measurement shows good agreement in both 80 kVp and 120 kVp x-ray beams. This numerical analysis based on iteratively calculation of fractional exposure per energy interval shows the high potential of usefulness of determination the x-ray spectra from the attenuated beam in diagnostic energy range.

• The korean journal of orthodontics
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• v.35 no.6 s.113
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• pp.409-419
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• 2005

Studies for diagnostic analysis using three-dimensional (3D) CT images are recently in progress and needs for 3D craniofacial analysis are increasing in the fields of orthodontics. It is especially essential to analyze the facial soft tissue after orthodontic treatment and orthognathic surgery. In this study 3D CT images of adults with normal occlusion were taken to analyze the facial soft tissue. Norms were obtained from CT images of adults with normal occlusion (12 males, 11 females) using a computer program named V works 4.0 program. 3D coordinate planes were established using soft tissue Nasion as the reference point and a total of 20 reproducible landmarks of facial soft tissue were obtained using the multiple reconstructive sectional images (axial, sagittal and coronal images) of the V works 4.0 program: soft tissue Nasion, Pronasale, Subnasale, Upper lip center, Lower lip center, soft tissue B, soft tissue Pogonion, soft tissue Menton, Endocanthion (Rt/Lt), Alare lateralis (Rt/Lt), Cheilion (Rt/Lt), soft tissue Gonion (Rt/Lt), Tragus (Rt/Lt), and Zygomatic point (Rt/Lt). According to the established landmarks and measuring method, the 3D CT images of adults with normal occlusion were measured and the normal positional measurements and their Net (${\delta}=\sqrt{{X^2}+{Y^2}+{Z^2}}$) values were obtained using V surgery program, In the linear measurement between landmarks, there was a significant difference between males and females except Na' -Sn and En(Rt)-En(Lt). The normal ranges of Na'-Zy, Na'-Ch and Na'-Go' (facial depth) were obtained, which was difficult to measure by two-dimensional (2D) cephalometric analysis and facial photographs. These data may be used as references for 3D diagnosis and treatment planning for patients with malocclusion and dentofacial deformity.

• Journal of Korean Biological Nursing Science
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• v.15 no.3
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• pp.122-132
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• 2013

Purpose: The purpose of this study was to evaluate the effect of periodic video education on knowledge about hemodialysis, patient role behavior and the physiologic index in patients with hemodialysis. Methods: One-group pretest-posttest design was applied. A total of 50 patients with hemodialysis at a university hospital hemodialysis unit in Daegu participated. Periodic video education about kidney function, diet, arteriovenous fistula management, medication, and exercise was administered to them for 12 weeks at intervals of 2 weeks. Before and after the education, the participants completed the self-administered questionnaires of knowledge about hemodialysis and patient role behavior and the measures of serum potassium and phosphorus concentration, weight gain between hemodialysis sessions, and adequacy of dialysis (Kt/V). Statistical analysis was performed using paired t-test. Results: Knowledge about hemodialysis and patient role behavior were significantly different between before and after education (p<.01). For the physiologic index, serum potassium concentration and weight gain between hemodialysis sessions were not significantly different but the serum phosphorus concentration and Kt/V were significantly different between before and after education (p<.05). Conclusion: The results suggest that the periodic video education for patients with hemodialysis contributed to the change and improvement in knowledge about hemodialysis, patient role behavior, and the physiologic index.

• Imaging Science in Dentistry
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• v.33 no.3
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• pp.151-159
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• 2003

Purpose: The purpose of this study is to evaluate the effectiveness and usefulness of newly developed personal computer-based software to eliminate the linear artifacts by the metal restorations. Materials and Methods: A 3D CT image was conventionally reconstructed using ADVANTAGE WINDOWS 2.0 3D Analysis software (GE Medical System, Milwaukee, USA) and eliminated the linear artifacts manually. Next, a 3D CT image was reconstructed using V-works 4.0/sup TM/(Cybermed Inc., Seoul, Korea) and the linear artifacts eliminated manually in the axial images by a skillful operator using a personal computer. A 3D CT image was reconstructed using V-works 4.0/sup TM/(Cybermed Inc., Seoul, Korea) and the linear artifacts were removed using a simplified algorithm program to eliminate the linear artifacts automatically in the axial images using a personal computer, abbreviating the manual editing procedure. Finally, the automatically edited reconstructed 3D images were compared to the manually edited images. Results and Conclusion: We effectively eliminated the linear artifacts automatically by this algorithm, not by the manual editing procedures, in some degree. But programs based on more complicated and accurate algorithms may lead to a nearly flawless elimination of these linear artifacts automatically.

• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.517-522
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• 2019

The purpose of this study is to determine the effective energy of CT X-ray beams by using the CT slice images of a CT number calibration insert part in the AAPM CT performance phantom. The CT number calibration insert part in the AAPM CT performance phantom was scanned five times by using a CT canner for 80, 100 and 120 kVp X-ray beams. The average value of CT numbers of each pin were measured for each CT slice image. The correlation coefficients were obtained by linear fit between the average value of CT numbers measured and liner attenuation coefficient under different energy at each pin calculated from data of NIST. A photon energy corresponding to the maximum value of the obtained correlation coefficient was determined as an effective energy. As a result, the effective energy was 56, 62 and 66~67 keV, respectively, for 80, 100 and 120 kVp X-ray beams.

• Journal of Korean Society of Forest Science
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• v.81 no.4
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• pp.346-356
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• 1992

The extensive Snake River floodplain in Northwest United States has experienced major changes in water channels and vegetation types due to floodings. To detect the change of wetland cover-types for the period of 1985 and 1988, post-classification comparison and image differencing change detection techniques were evaluated using Landsat-5 TM digital data. Differenced infrared-band images indicated better accuracy indices than any visible-band images. A thresholding technique was applied to identify the change and no change categories from the transformed images produced by image differencing. The problems in using different accuracy indices, including the Kappa coefficient of agreement, overall accuracy, producer's accuracy, user's accuracy, and average accuracy(based on both the producer's and user's accuracy approaches) in determining an optimal threshold level, were examined.