• Progress in Medical Physics
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• v.30 no.4
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• pp.120-127
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• 2019

Purpose: This study was designed to evaluate the dosimetric performance of Mobius3D by comparison with an aSi-based electronic portal imaging device (EPID) and Octavius 4D, which are conventionally used for patient-specific prescription dose verification. Methods: The study was conducted using nine patients who were treated by volumetric modulated arc therapy. To evaluate the feasibility of Mobius3D for prescription dose verification, we compared the QA results of Mobius3D to an aSi-based EPID and the Octavius 4D dose verification methods. The first was the comparison of the Mobius3D verification phantom dose, and the second was to gamma index analysis. Results: The percentage differences between the calculated point dose and measurements from a PTW31010 ion chamber were 1.6%±1.3%, 2.0%±0.8%, and 1.2%±1.2%, using collapsed cone convolution, an analytical anisotropic algorithm, and the AcurosXB algorithm respectively. The average difference was found to be 1.6%±0.3%. Additionally, in the case of using the PTW31014 ion chamber, the corresponding results were 2.0%±1.4%, 2.4%±2.1%, and 1.6%±2.5%, showing an average agreement within 2.0%±0.3%. Considering all the criteria, the Mobius3D result showed that the percentage dose difference from the EPID was within 0.46%±0.34% on average, and the percentage dose difference from Octavius 4D was within 3.14%±2.85% on average. Conclusions: We conclude that Mobius3D can be used interchangeably with phantom-based dosimetry systems, which are commonly used as patient-specific prescription dose verification tools, especially under the conditions of 3%/3 mm and 95% pass rate.

• Journal of Elementary Mathematics Education in Korea
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• v.18 no.2
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• pp.257-278
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• 2014

The concept of zero(0) and calculations involving 0 are a few of the most difficult topics that students experience in learning mathematics. Therefore, it implies that proper guidance to help students understand the desirable concept of 0 and acquire calculating process involving 0 should be provided when we teach numbers and operations. This study aims to investigate instructional situations in relation to the errors of 0 and to search for efficient ways to teach them based on the previous research. To do this, we analysed elementary mathematics textbooks and workbooks. The result showed that $0{\div}$(a number) and the division of which quotient includes 0 as a middle digit lacked in current textbooks and workbooks. We devised the learning activities of the two topics for 3rd grades and 4th grades, respectively. We expect that the activities will be helpful to devise learning activities of textbook and suggest some implications for teaching the calculations involving 0.

• Korean Journal of Food Science and Technology
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• v.43 no.6
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• pp.742-746
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• 2011

To increase the quality of Korean traditional yakju, we prepared seed cultures by fermentation at $20^{\circ}C$ for 2 days after addition of 140% water, 3% nuruk and 1.5% yeast into cooked rice. After the 200% cooked rice, 120% water and 0.08% commercial saccharifying enzyme were added to seed cultures and fermented for 2 days at $20^{\circ}C$, wild ginseng was added and then further fermented for 5 days. Physicochemical properties of traditional yakju were investigated. Ethanol was produced (18.5%) by the addition of 1.2% wild ginseng. However, ethanol content was not increased by addition of microwave treated-wild ginseng and rice (either cooked rice or raw). The traditional yakju obtained by fermentation at $20^{\circ}C$ for 5 days, after 90 sec of microwave treated-wild ginseng was added into main fermentation broth, showed good total acceptability and also contained 791 ppm saponin.

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.4
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• pp.280-292
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• 2017

Hail is not a frequently occurring weather event, and there are even fewer reports of hail damages to forest stands. Since the 2000s, an increase in hail incidence has been documented in Europe and the United States. In Korea, severe hails occurred in Jeollanam-do province on May 31 and in Gyeongsangbuk-do province on June 1, 2017. Hail size was ranged from 0.5 to 5.0 cm in diameter in Jeollanam-do, and from 1.5 to 3.0 cm in Gyeongsangbuk-do. This study was aimed to analyze the hail damages to forests by species and topography based on damage-categorized maps created by using drones and aerial photographs, and to analyze relationships of the damages with meteorological factors. The total damaged forest area was 1,163.1ha in Jeollanam-do, and 2,942.3ha in Gyeongsangbuk-do. Among the 'severe' damaged area 326.7ha, 91% was distributed in Jeollanam-do, and concentrated in the city of Hwasun which covers 57.2% of the total 'severe' damaged area. The most heavily damaged species was Korean red pine(Pinus densiflora S. & Z.) followed by P. rigida. Most broad-leaved trees species including oaks were recovered without any dead trees found. Liliodendron tulipifera was the most severely damaged in terms of the rate of 'severe' degree individuals which are needed to be checked whether they will die or be recovered. Cause of the death of pines was considered as the combination of physical damage caused by the hail and long-lasting drought with high air temperature that occurred before and after the hail event. No pathogens and insects were found which might have affected to tree deaths. We suggested a dieback mechanism of the pine trees damaged by hail and drought.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.68.2-68.2
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• 2010

We present near-infrared (NIR) spectra of 6 young stellar objects (YSOs) around the supernova remnant G54.1+0.3 obtained with TripleSpec, a slit-based NIR cross-dispersion echelle spectrograph on th 5-m Palomar Hale telescope covering the entire NIR atmospheric window of 1-2.4 micron. These YSOs, whose formation was possibly triggered by the progenitor of G54.1+0.3, show significant mid-infrared (MIR) excess and have been proposed to be late O- and early B-type YSOs based on their spectral energy distribution. Our TripleSpec observations reveal the existence of strong H and He I lines, consistent with the previous interpretation of their spectral types, while the absence of Br-gamma emission line indicates that the YSOs do not have a nearby circumstellar disk. We discuss the relation between these YSOs and G54.1+0.3 based on the TripleSpec data and previous photometric data as well.

• International journal of advanced smart convergence
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• v.12 no.2
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• pp.47-55
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• 2023

The automotive industry is undergoing a paradigm shift due to the convergence of IT and rapid digital transformation. Various components, including embedded structures and systems with complex architectures that incorporate IC semiconductors, are being integrated and modularized. As a result, there has been a significant increase in vehicle defects, raising expectations for the quality of automotive parts. As more and more data is being accumulated, there is an active effort to go beyond traditional reliability analysis methods and apply machine learning models based on the accumulated big data. However, there are still not many cases where machine learning is used in product development to identify factors of defects in performance and durability of products and incorporate feedback into the design to improve product quality. In this paper, we applied a prediction algorithm to the defects of automotive door devices equipped with automatic responsive sensors, which are commonly installed in recent electric and hydrogen vehicles. To do so, we selected test items, built a measurement emulation system for data acquisition, and conducted comparative evaluations by applying different machine learning algorithms to the measured data. The results in terms of R² score were as follows: Ordinary multiple regression 0.96, Ridge regression 0.95, Lasso regression 0.89, Elastic regression 0.91.

• Journal of Microbiology and Biotechnology
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• v.33 no.2
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• pp.188-194
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• 2023

Microbacterium elymi KUDC0405^T was isolated from the rhizosphere of Elymus tsukushiensis from the Dokdo Islands. The KUDC0405^T strain was Gram-stain-positive, non-spore forming, non-motile, and facultatively anaerobic bacteria. Strain KUDC0405^T was a rod-shaped bacterium with size dimensions of 0.3-0.4 × 0.7-0.8 ㎛. Based on 16S rRNA gene sequences, KUDC0405^T was most closely related to Microbacterium bovistercoris NEAU-LLE^T (97.8%) and Microbacterium pseudoresistens CC-5209^T (97.6%). The dDDH (digital DNA-DNA hybridization) values between KUDC0405^T and M. bovistercoris NEAU-LLE^T and M. pseudoresistens CC-5209^T were below 17.3% and 17.5%, respectively. The ANI (average nucleotide identity) values among strains KUDC0405^T, M. bovistercoris NEAU-LLE^T, and M. pseudoresistens CC-5209^T were 86.6% and 80.7%, respectively. The AAI (average amino acid identity) values were 64.66% and 64.97%, respectively, between KUDC0405^T and its closest related type strains. The genome contained 3,596 CDCs, three rRNAs, 46 tRNAs, and three non-coding RNAs (ncRNAs). The genomic DNA GC content was 70.4%. The polar lipids included diphosphatydilglycerol, glycolipid, phosphatydilglycerol, and unknown phospholipid, and the major fatty acids were anteiso-C_17:0 and iso-C_16:0. Strain KUDC0405^T contained MK-12 as the major menaquinone. Based on genotypic, phylogenetic, and phenotypic properties, strain KUDC0405^T should be considered a novel species within the genus Microbacterium, for which we propose the name M. elymi sp. nov., and the type strain as KUDC0405^T (=KCTC 49411^T, =CGMCC1.18472^T).

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.3
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• pp.59-72
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• 2004

In this paper, we classify various attacks that may damage the embedded watermark signal into waveform attack and synchronization attack. And for the specialized defense against the two kinds of attacks we propose a new watermarking scheme named as two layer watermarking method. It consists of a synchronization layer to prepare for the geometrical attack such as rotation and shift and a marking layer 0 embed the watermark signal actually. Namely, the synchronization layer only determines the target region where the watermark signal will be embedded or extracted. And the marking layer spreads the watermark signal over the image as the conventional watermarking methods do. Using the layered structure, the proposed method overcomes the problem that the conventional watermarking methods that do not use the original image at the verification side are most vulnerable to geometrical attacks.

• Journal of radiological science and technology
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• v.21 no.1
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• pp.29-34
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• 1998

The purpose of simple abdomen erect projection is to see the fluid level which indicates gastrointestinal ileus or free air due to perforation. we do not have to insist on low kVp technique in simple abdomen erect position as long as we can detect the fluid level and free air shadow. Therefore, the author tried to decrease patient dose by high kVp technique and to improve the image quality due to motion artifact by reduction of exposure time. [Methods] Experiment 1. * screen/film SRO1000/HRH * exposure factor : $140\;kvp{\pm}5\;kv$ with added filters, 200 mA, 0.01 sec * phantom : Acryles : 15.0 cm(equivalent to 17 cm body thickness) 17.5 cm(equivalent to 21 cm body thickness) 20.0 cm (equivalent to 25 cm body thickness) With the exposure factor for same film density($D=0.8{\pm}0.1$) and with the materials above, we tried to find out entrance skin dose and gonad dose for both male and female. Experiment 2. Burger's phantom radiography were checked to see whether there was any change of image quality according to the kVp and the added filters. Experiment 3. Using rotating meter(self made), we examined the motion artifact and the exposure time limitation. [Results and conculution] 1. Using high voltage technique of 140 kVp with added filter, Skin dose, testicle dose and ovary dose decrease to 89.3%, 47% and 71.4% respectively compare to 70 kVp technique, 2. No great changes of Burger's phantom image has detected as from 70 kVp to 140 kVp and the air hole size of Burger's phantom over 0.028 cc(Diameter 3 mm, hight 4 mm) can be distinghished. 3. 0.01 sec(1 pulse) exposure time is possible in the single phase full wave rectification that why we can quitely reduce the unsharness caused by patient's movement.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.33.1-33.1
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• 2016

We report detection of short-term flux variability in multi-epoch observations and intraday variability in polarized emission at millimeter-wavelength from S5 0716+714 using Korean VLBI Network (KVN) radio telescopes. Over the whole observation epochs, the source shows significant inter-month variations at K- and Q-band with modulation indices of 19% at K-band and 36% at Q-band. In each epoch, the source shows monotonic flux increase in Epoch 1 and 3, and monotonic flux decrease in Epoch 2 and 4. We found an inverted spectrum with mean spectral indices of -0.57 in Epoch 1 and -0.15 in Epoch. On the contrary, we found relatively steep indices of 0.24 and 0.17 in Epoch 2 and Epoch 4, respectively. In the study of intraday variability of polarization, we found significant variations in the degree of linear polarization at 86 GHz, and in polarization angle at 43 and 86 GHz during ~10 h. The spectrum of the source is quite flat with spectral indices of -0.07 to 0.07 at 22-43 GHz and -0.23 to 0.04 at 43-86 GHz. The measured degree of the linear polarization ranges from 2.3% to 3.3 % at 22 GHz, from 0.9% to 2.2 % at 43 GHz and from 0.4 % to 4.0 % at 86 GHz, yielding prominent variations at 86 GHz over 4-5 h. The linear polarization angle is in the range of 4 to $12^{\circ}$ at 22 GHz, -39 to $81^{\circ}$ at 43 GHz, and 66 to 119 at 86 GHz with a maximum rotation of $110^{\circ}$ at 43 GHz over ~4 h. We estimated the Faraday rotation measures (RM) ranging from -9200 to 6300 rad m-2 between 22 and 43 GHz, and from -71000 to 7300 rad m-2 between 43 and 86 GHz, respectively. The frequency dependency of RM was investigated, yielding a mean power-law index, a, of 2.0. This implies that the polarized emission from S5 0716+714 at 22-86 GHz moves through a Faraday screen in or near the jet of the source.