• Progress in Medical Physics
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• v.27 no.2
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• pp.79-85
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• 2016

The objective of this study is to increase the accuracy of dose transmission in radiation therapy using two types of treatment tables, standard exact couch (Varian 21EX, Varian Medical Systems, Milpitas, CA) and 6D robotic couch (Novalis, BrainLAB A.G., Heimstetten, Germany)). We examined the dose attenuation based on the two types of treatment tables and studied the dose of attenuation using the phase (In/Out) for the standard exact couch. We measured the relative dose according to the incident angle of a penetrative photon beam under a treatment table. The incident angle of the photon beam was from $0^{\circ}$ to $360^{\circ}$ in the increments of $5^{\circ}$. The reference angle was set to $0^{\circ}$. Furthermore, the relative dose of the 6D robotic couch was measured using 6 MV and 15 MV, and that of the standard exact couch was measured at the sliding rail position (In-Out) using 6 MV and 10 MV. In the case of the standard exact couch, the measured relative dose was 16.53% (rails at the "In position," $175^{\circ}$, 6 MV), 12.42% (rails at the "In position," $175^{\circ}$, 10 MV), 13.13% (rails at the "Out position," $175^{\circ}$, 6 MV), and 9.96% (rails at the "Out position," $175^{\circ}$, 10 MV). In the case of the 6D robotic couch, the measured relative dose was 6.82% ($130^{\circ}$, 6 MV) and 4.92% ($130^{\circ}$, 15 MV). The photon energies were surveyed at the same incident angle. The dose attenuation for an energy of 10 MV was 4~5% lower than that for 6 MV. This indicated that the higher photon energy, lesser is the attenuation. The results of this study indicated that the attenuation rate for the 6D robotic couch was confirmed to be 1% larger than that for the standard exact couch at 6 MV and $180^{\circ}$. In the case of the standard exact couch, the dose attenuation was found to change rapidly in accordance with the phase ("In position" and "Out position") of the sliding rail.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.365-370
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• 2012

In this study, Economic analysis of supercritical coal-fired power plant with $CO_2$ capture process was performed. For this purpose, chemical absorption method using amine solvent, which is commercially available and most suitable for existing thermal power plant, was studied. For the evaluation of the economic analysis of coal-fired power plant with post-combustion $CO_2$ capture process in Korea, energy penalty after $CO_2$ capture was calculated using the power equivalent factor suggested by Bolland et al. And the overnight cost of power plant (or cost of plant construction) and the operation cost reported by the IEA (International Energy Agency) were used. Based on chemical absorption method using a amine solvent and 3.31 GJ/$tonCO_2$ as a regeneration energy in the stripper, the net power efficiency was reduced from 41.0% (without $CO_2$ capture) to 31.6% (with $CO_2$ capture) and the levelized cost of electricity was increased from 45.5 USD/MWh (Reference case, without $CO_2$ capture) to 73.9 USD/MWh (With $CO_2$ capture) and the cost of $CO_2$ avoided was estimated as 41.3 USD/$tonCO_2$.

• Journal of Nutrition and Health
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• v.54 no.2
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• pp.165-178
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• 2021

Purpose: This study examined the eating-out patterns of Korean infants and school-aged children and compared diet quality. Methods: Data were obtained from the 2016-2018 Korea National Health and Nutrition Examination Survey. The subjects were 306 children aged 3 to 11 years old that ate dinner at restaurants. Percentage energy intakes of 24 food groups were calculated, and cluster analysis was used to identify eating-out patterns. Diet quality was assessed by calculating percentage energy and nutrient intakes using one-third of the 2015 Dietary Reference Intakes for Korean (KDRIs), nutrient adequacy ratio (NAR), mean adequacy ratio (MAR), and index of nutritional quality (INQ). Results: Cluster analysis identified 2 eating-out patterns, that is, a 'rice-centered' (53%) and a 'mixed diet' (47%) pattern. For those with the mixed diet pattern, ratios of carbohydrates, protein, and fat to total calories were 48:20:31, whereas for the rice-centered pattern, ratios were 62:15:21 (p < 0.001). Intakes of energy and most nutrients in the mixed diet pattern were excessive, but the intakes of the most nutrients in the rice-centered pattern were much lower than their KDRIs. MARs were higher for the mixed diet pattern than the rice-centered pattern (0.74 vs. 0.66) (p < 0.001), and INQs for vitamin C (p = 0.007) and calcium (p = 0.018) were lower for the rice-centered pattern, whereas INQ for iron (p = 0.003) was lower for the mixed diet pattern. Conclusion: The quality of meals for infants and school-aged children depended on eating-out patterns, but the rice-centered and mixed diet patterns both failed to provide an appropriately balanced meal pattern. The results of this study suggest that healthy menus need to be developed for children in restaurants.

• The Journal of Korean Society for Radiation Therapy
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• v.29 no.2
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• pp.43-51
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• 2017

Purpose: The purpose of this study is to evaluate the dosimetric effects of couch attenuation and air gaps using 3D phantom for prone breast radiation therapy. Materials and method: A 3D printer(Builder Extreme 1000) and computed tomography (CT) images of a breast cancer patient were used to manufacture the customized breast phantom. Eclipse External Beam Planning 13.6 (Varian Medical Systems Palo Alto, CA, USA) was used to create the treatment plan with a dose of 200 cGy per fraction with 6 MV energy. The Optically Stimulated Luminescence Detector(OSLD) was used to measure the skin dose at four points (Med 1, Med 2, Lat 1, Lat 2) on the 3D phantom and ion-chamber (FC65-G) were used to perform the in-vivo dosimetry at the two points (Anterior, Posterior). The Skin dose and in-vivo dosimetry were measured with reference air gap (3 cm) and increased air gaps (1, 2, 3, 4, 5, 6 cm) from reference distance between the couch and 3D phantom. Results: As a result, measurement for the skin dose at lateral point showed a similar value within ${\pm}4%$ compared to the plan. While the air gap increased, skin dose at medial 1 was reduced. And it was also reduced over 7 % when the air gap was more than 3 cm compared to radiation therapy plan. At medial 2 it was reduced over 4 % as well. The changes of dose from variety of the air gap showed similar value within ${\pm}1%$ at posterior. As the air gap was increased, the dose at anterior was also increased and it was increased by 1 % from the air gap distance more than 3 cm. Conclusion: Dosimetrical measurement using 3D phantom is very useful to evaluate the dosimetric effects of couch attenuation and air gaps for prone breast radiation therapy. And it is possible to reduce the skin dose and increase the accuracy of the radiation dose delivery by appling the optimized air gap.

• Journal of Nutrition and Health
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• v.43 no.3
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• pp.224-232
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• 2010

The prevalence of heart failure (HF) is increasing globally and growing evidence has shown that dietary factors play an important role in preventing and improving prognosis of HF. However, little data on nutrient intake in Korean HF patients which are available to develop dietary guidelines for HF. The aims of this study were to estimate nutrient intake in 78 HF patients and evaluate whether the estimated nutrient intake is appropriate compared to dietary reference intake for Koreans. Data are presented as the ratio of actual intake and estimated average requirement (EAR) for each nutrient. The result showed that the average nutrient intakes including total energy and protein met EAR in total patients. However, the deficiencies in mineral and vitamin intakes were found. Moreover, the proportion of subjects with lower intake than EAR was substantial. The results showed that the proportion of male HF patients with inferior intakes to EAR in calcium, potassium (compared to adequate intake: AI), folate and vitamin $B_{12}$ were 38%, 79%, 38%, and 65%, respectively. Also, the proportion of female HF patients with inferior intakes to EAR in calcium, potassium (compared to AI), folate and vitamin $B_{12}$ were 35%, 88%, 38% and 40%, respectively. In particular, the elderly with HF ($\geq$ 70 yrs, n = 28) showed more serious deficiencies in calcium, potassium (compared to AI), folate and vitamin $B_{12}$. In summary, the intakes of potassium, calcium, folate, and vitamin B12 were not sufficient to meet EAR in HF patients. Furthermore, the proportions of subjects with lower intake than EAR in these nutrients were substantial, raising the possibility that these micronutrients may be involved in the pathogenesis of HF. Practical dietary guideline for HF patients is needed to improve prognosis of HF.

• Korean Journal of Remote Sensing
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• v.37 no.5_3
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• pp.1373-1387
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• 2021

Forest fire poses a significant threat to the environment and society, affecting carbon cycle and surface energy balance, and resulting in socioeconomic losses. Widely used multi-spectral satellite image-based approaches for burned area detection have a problem in that they do not work under cloudy conditions. Therefore, in this study, Sentinel-1 Synthetic Aperture Radar (SAR) data from Europe Space Agency, which can be collected in all weather conditions, were used to identify forest fire damaged area based on a series of processes including Principal Component Analysis (PCA) and K-means clustering. Four forest fire cases, which occurred in Gangneung·Donghae and Goseong·Sokcho in Gangwon-do of South Korea and two areas in North Korea on April 4, 2019, were examined. The estimated burned areas were evaluated using fire reference data provided by the National Institute of Forest Science (NIFOS) for two forest fire cases in South Korea, and differenced normalized burn ratio (dNBR) for all four cases. The average accuracy using the NIFOS reference data was 86% for the Gangneung·Donghae and Goseong·Sokcho fires. Evaluation using dNBR showed an average accuracy of 84% for all four forest fire cases. It was also confirmed that the stronger the burned intensity, the higher detection the accuracy, and vice versa. Given the advantage of SAR remote sensing, the proposed statistical processing and K-means clustering-based approach can be used to quickly identify forest fire damaged area across the Korean Peninsula, where a cloud cover rate is high and small-scale forest fires frequently occur.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.1
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• pp.1-10
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• 2013

Purpose: This study is conducted to evaluate the job stressors for opticians in Ulsan city. Methods: We investigated job stress of 180 opticians working in Ulsan. The results of this study from The Korean standard job stressors assessment tool developed by Korea occupational safety and health agency (KOSHA) was compared with Korean reference value. The questionnaire on the social, demographic characteristics of opticians was also used to find the factors affecting to job stressors by using multiple linear regression analysis. Results: Among the eight fields of stressors, the interpersonal conflict (the median value; 33.4, the measurements; men; 38.8, women; 41.5) and company culture (the median; 41.7, the measurements; men; 47.4, women; 49.3) were higher than the median value of the Korean workers. By multiple linear regression analysis, the significant factors to the interpersonal conflict were the duty, working hours, unmarried, average salary. In terms of the company culture, last school, rest day of month, job career, average salary and working hours were significantly associated to the score of company culture. Conclusions: Based on the results, important factor in the formation of a positive organizational culture through to improve treatment of opticians investigation and mutual horizontal communication systems in the workplace for the manage on interpersonal conflict and company culture.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.6
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• pp.75-81
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• 2010

The segmentation of cartilage is crucial for the diagnose and treatment of osteoarthritis (OA), and has mostly been done manually by an expert, requiring a considerable amount of time and effort due to the thin shape and vague boundaries of the cartilage in MR (magnetic resonance) images. In this paper, we propose a fully automatic method to segment cartilage in a knee joint on MR images. The proposed method is based on a small number of manually segmented images as the training set and comprised of an initial per patch segmentation process and a global refinement process on the cumulative per patch results. Each patch for per patch segmentation is positioned by classifying the bone-cartilage interface on the pre-segmented bone surface. Next, the shape and intensity priors are constructed for each patch based on information extracted from reference patches in the training set. The ratio of influence between the shape and intensity priors is adaptively determined per patch. Each patch is segmented by graph cuts, where energy is defined based on constructed priors. Finally, global refinement is conducted on the global cartilage using the results of per patch segmentation as the shape prior. Experimental evaluation shows that the proposed framework provide accurate and clinically useful segmentation results.

• Journal of the Korean Society of Costume
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• v.66 no.6
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• pp.95-109
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• 2016

The process of making fashion accessories brings many benefits to visually impaired people. It helps the development of their tactile sensation, improves their aesthetic attitude, creativity, and imagination, and brings energy to their life. The current accessory making education in Korea is targeted to people with normal vision, and does not reflect the specific needs of the visually impaired. This causes a lot of trouble in educating the visually impaired. Therefore, this study aims to increase the efficiency of accessory making education by selecting curriculum and material that are appropriate and systematic for the visually impaired. In order to understand visual impairment, literature review was conducted to examine the definition and classifications of the impairment. Research was also done regarding material types and production method of fashion accessory. The study also designed an education program, including teaching guidelines, by referring to literature related to fashion accessory design, teaching guideline. The study conducted 12 experiments based on the results from April to June 2014. After revising and supplementing the teaching method, 2nd set of experiments were conducted from July to September 2014. Each class lasted for one and a half hour every week, and the class was composed of 6 students, 1 instructor and 1 volunteer. After each class, interviews were done to collect student opinions about the curriculum and material. Total experiment results and interview were reflected in constructing the final education program. The result of the experiments and interviews showed that selecting the accessory materials for class must be selected carefully. The visually-impaired students were very sensitive to the size, texture, shape, hole size of beads and length of material. After the experiments, all the students were able to distinguish the size and shape of the beads well, and finished the accessories using the given materials. The study verified that there is a need for another approach when educating the visually impaired about fashion accessory design. Many factors need to be considered from selecting materials to class contents. This study will contribute as a reference to fashion accessory making education as well as other design education for the visually impaired.

• Journal of the Korean Wood Science and Technology
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• v.44 no.1
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• pp.75-84
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• 2016

Thermal performance of wooden houses used by building materials effectively contributing to building energy saving has been improved. However, the performance was decreased to the condensation and mould growth from exterior wall because the moisture control was difficult to high insulation and airtightness. Therefore, the hygrothermal performance of exterior wall, that selected 5 types of wooden houses, evaluated using the hygrothermal simulation program: heat and moisture behavior, condensation and mould growth risk. Wooden houses were selected Rural houses standard plans '10 and '14, $2^{{\prime}{\prime}}{\times}6^{{\prime}{\prime}}$ type, EIFS and wood-based passive house. And the wall A, B, C, D and E were determined by layer component of each wall. The U-value of exterior wall are 0.171, 0.172, 0.221, 0.150, $0.079W/m^2K$. The OSB absolute water content of the wall A and C was exceeds the reference value of 20%, and it was confirmed that condensation occur at insulation material inner surface through the condensation evaluation in the winter. The wall D and E showed excellent results with condensation and water content evaluation compared to others. However, mould growth risk assessment in all five types of wall had have risk. We were determined that hygrothermal performance difference of exterior wall occur the difference in the layer structure rather than in thermal performance.