• Korean Journal of Optics and Photonics
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• v.34 no.4
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• pp.157-169
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• 2023

Augmented reality (AR) using a head mounted display (HMD) is used in various fields such as military, medicine, manufacturing, gaming, and education. In this paper, we discuss the design and fabrication of the AR optical system, which is most essential for HMD. The AR optical system for HMD requires a wide transparent area in which the augmented image of the display and the real world can be viewed at the same time. To this end, an AR optical system was designed and manufactured by dividing it into three parts according to each characteristic. Also, the refractive index of the ultra-violet (UV) adhesive layer required to make the three optical systems into one complete AR optical system was considered from the design stage to minimize the optical path shift phenomenon when the input light source passes through the UV adhesive layer. In addition, when designing the AR optical system, two aspheric surfaces were used to compensate for off-axis aberration and to be suitable for mass production. Finally, for HMD mass production, an aspheric AR optical system with a thickness of 11 mm, a diagonal field of view of 40°, and a weight of 11.3 g was designed and manufactured.

• Journal of Korea Water Resources Association
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• v.41 no.2
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• pp.229-239
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• 2008

This study is to derive the fourth-order Geomorphologic Instantaneous Unit Hydrograph (GIUH), driven for only third-order basin, for the application of GIUH to various types of basin. The second, third, and fourth order GIUHs were compared for various topographical conditions. The results showed lower peak runoff and later peak time in GIUH with higher stream order. Initial state probability was estimated from a function of geomorphologic parameters such as area ratio and bifurcation ratio for the application of GIUH. However, initial state probabilities and early parts of the GIUHs have negative values for many basins due to the inherent errors in the parameters. Initial state probability was calculated by area ratio of direct drainage using ArcView GIS 3.2 model to solve the problem. GIUHs were estimated for three basins, Sanganmi, Byeongcheon, and Sangye, using the above suggested method, and the results showed that the method is free of the problem.

• Korean Journal of Community Nutrition
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• v.27 no.6
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• pp.492-502
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• 2022

Objectives: This study examines the foodservice status of kindergartens attached to elementary schools in Seoul. We further determine the perception of elementary school principals and kindergarten assistant principals on the foodservice management for kindergartens. Methods: This survey was conducted from July 17 to 23, 2019, enrolling 207 kindergartens attached to elementary schools in Seoul. Questionnaires were sent to principals of elementary schools and assistant principals of kindergartens, and the data obtained from 89 kindergartens were included in the analysis. The questionnaire consisted of four parts: general information on subjects, foodservice management status, foodservice management status during elementary school vacations, and the perception of principals of elementary schools and assistant principals of kindergartens on foodservice management. Data are presented as frequency and percentage or mean and standard deviation. Statistical comparison between principals of elementary schools and assistant principals of kindergartens was conducted by paired t-test, chi-square test, and Pearson's correlation analysis. Results: A separate menu (10.1%) or recipe (20.2%) that considers preschooler characteristics was rarely used for foodservice at kindergartens attached to elementary schools. Most kindergartens did not have a separate dining space (3.4%) or a dedicated cook (93.3%). Although most kindergartens (92.1%) had operational foodservice during elementary school vacations, non-professional staff and non-nutrition teacher were mainly in charge of organizing the menu and purchasing ingredients (34.1% and 41.5%, respectively). The rate of using a contract catering company (28.0%, 23.2%) was also high. Both elementary school principals and assistant principals of kindergartens showed a high perception of the necessity for providing responsibility allowances for nutrition teachers and improving the cooking environment for kindergartens during elementary school vacations. Conclusions: There is a need for policies and administrative support measures to improve the quality of foodservices for kindergartens attached to elementary schools.

• Applied Biological Chemistry
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• v.49 no.4
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• pp.309-314
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• 2006

This study was performed to confirm the physicochemical properties and physiological activities according to cultivar and parts of Ulsan sweet persimmons. The proximate composition of the sweet persimmons was moisture $77.68{\sim}84.65%$, crude ash $0.3{\sim}0.6$, crude fat $0.29{\sim}0.39$ and crude protein $0.52{\sim}0.61%$. Confirmed organic acids and free sugars in sweet persimmons were malic, citric, succinic, and fumaric acids, along with fructose, glucose and sucrose. The major fatty acids were linolenic, vaccenic and palmitic acids. Also, K is the highest mineral in sweet persimmons that accounts for the majority of mineral, more than 60% as $84.9{\sim}103.7mg%$. Contents of vitamin C, total phenolic compounds and flavonoids were the highest in Fuyu peel as 139.91, 169.36 and 60.79mg%, respectively, Electron donating ability and xanthine oxidase inhibition were the highest in Fuyu peel as $30.6{\sim}91.2$ and $26.3{\sim}91.9mg%$, respectively. Nitrite scavenging activity was higher in peel than flesh as $51.0{\sim}76.4mg%$ with slight difference depending on cultivar.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.7
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• pp.886-890
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• 2008

Levels of minerals, vitamin, amino acids, fatty acids and chemical compositions were determined in the fleshy parts that are used for food. The moisture, crude protein, crude lipid, crude ash and carbohydrate contents of masou salmon were $73.6{\pm}0.4$, $17.7{\pm}0.3$, $3.3{\pm}0.2$, $1.3{\pm}0.1$ and $4.1{\pm}0.2%$, respectively. Potassium was the highest followed by phosphorus, calcium and sodium. The vitamin C and E levels in masou salmon were 600 and $200\;{\mu}g/100\;g$, respectively. Sixteen amino acids were detected and essential amino acids among them are threonine, valine, methionine, isoleucine, leucine, phenylalanine, lysine, arginine, and histidine. Oleic acid was the most abundant fatty acid in masou salmon and polyunsaturated fatty acids were EPA, DHA, linoleic acid, $\alpha$-linolenic acid, $\gamma$-linolenic acid and arachidonic acid. These results may offer a scientific basis for the commercial use of masou salmon.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.9
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• pp.1412-1418
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• 2013

The nutritional components of 14 new cultivars of pak choi (Brassica rapa L. ssp. chinensis) from China were analyzed and compared with 4 cultivars of Chinese cabbage (Brassica rapa L. ssp. pekinensis) popular in Korea. Leaves were separated into green parts (GP) and white parts (WP) for the analyses. The moisture and ash content in the 14 new cultivars of pak choi were not significantly different from the currently popular cultivars of Chinese cabbage. In addition, the levels of vitamin C and E were very similar between the two kinds of Brassica rapa. In contrast, the overall mineral content was higher in the new pak choi cultivars. Specifically, minerals important for human health, calcium and magnesium, were significantly greater in pak choi cultivars (calcium GP 2.57, WP 2.04; magnesium GP 0.422, WP 0.301 mg/g fresh weight) compared to currently popular cultivars (calcium GP 0.805, WP 0.477; magnesium GP 0.244, WP 0.101 mg/g fresh weight). Although the content of reducing sugars was similar, cellulose content (which correlates with the hardness of plant tissue) was four times higher in the new pak choi cultivars compared to currently popular cultivars. These results demonstrate that the new pak choi cultivars have superb nutritional benefits for human health and could be a good food source as a daily staple vegetable.

• Applied Biological Chemistry
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• v.49 no.1
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• pp.43-48
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• 2006

This study was performed to confirm physiological activities according to cultivars and parts of Ulsan pear (wonhwang, pungsu, whangkeum, whasan and shingo). Total contents of phenolic compounds from peel, pulpy substance and core were 699.3-800.6, 51.5-112.5 and 254.0-401.5 mg/100 g as tannic acid equivalent, respectively. There were difference contents by cultivars, and peel and core of shingo and pulpy substance of wonhwang showed high contents, respectively. Total flavonoid contents of peel, pulpy substance and core were 125.2-164.2, 25.9-35.9 and 45.1-60.0 mg/100g, respectively and those of shingo cultivar showed comparatively high. Electron donating ability was in the order of peel (66.1-90.7%), core (48.5-82.8%) and pulpy substance (24.9-58.2%), and whasan cultivar showed comparatively low. Nitrite scavenging activity was in the order of peel (58.2-100.8%), core (59.5-86.2%), pulpy substance (39.9-82.5%). There were little difference by cultivars of core but peel and pulpy substance of shingo cultivar showed comparatively low nitrite scavenging activity. And as the concentration of each extract increased, nitrite scavenging activity increased. Xanthine oxidase inhibition rate was in the order of peel (14.1-75.4%), core (5.3-71.8%), pulpy substance (2.2-67.5%). And there little difference by cultivars and which was increased as the concentration of each extract increased.

• Korean Journal of Heritage: History & Science
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• v.55 no.1
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• pp.51-61
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• 2022

Earthenware horn cups with horse head decorations were excavated from Tomb No. 7 of Bokcheon-dong, Dongraegu, Busan Metropolitan City. Made of earth in the shape of a horn, these cups are considered to have been used to drink alcohol or beverage. Large numbers of earthenware horn cups of various shapes were excavated from tombs located in the old territories of Silla and Gaya. A pair of earthenware horn cups were excavated from Tomb No. 7, and the two cups are almost identical in overall shapes and manufacturing techniques despite different sizes. Conservation treatment was carried out for the bigger one of the two horn cups this time. There are two cracks toward the horse head decorations around the mouth with missing parts observed. The chest of the horse touches the ground with one side decorating the horse head and the other side facing the conical mouth of the horn cup. It is in the U shape, striking a balance based on two legs attached behind. The surface of the horn cup was made with a potter's wheel, and the connection to the horse head has traces of cutting and trimming. The horse head is expressed realistically with its features including the ears, eyes, nose, and mouth well apprehended and its color is grey This study intended to investigate manufacturing techniques of the artifact by examining its internal structure through the condition survey in a non-destructive way. CT imaging was used to figure out its manufacturing techniques and to diagnose its condition, and accordingly the scientific conservation treatment was conducted to stabilize the artifact. The precise diagnosis on conservation condition found that there are two chips in the spout with their cracks extended. One of the chips is connected with separation added to the crack. The material which has been used for connection in the past was collected for the infrared spectroscopic analysis, which was identified to be nitrocellulose resin for the connection. Therefore, this conservation treatment focused on removing the old material and preventing the spread of cracks. Before conservation treatment, the condition survey and scientific examination for the artifact were carried out to secure data about the earthenware horn cup with horse head decorations(Treasure). Based on them, effective plans for its conservation treatment was sought for and then existing adhesive was safely removed, and restoration material was selected to take into account its reversibility. In addition, the conservation treatment according to optimal methodologies was conducted through the consultation meeting with experts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.5
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• pp.563-568
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• 2007

We report that the gamma linolenic acid content of pork is higher in finishing pigs fed diets containing hemp seed oil, evening primrose oil or borage oil as the sources of gamma linolenic acid. Thirty-six three crossing swines ($Landrace{\times}Yorkshire{\times}Duroc$), 80 kg in body weight, were randomly separated into four treatment groups with three pens per treatment and three animals per pen. The finishing swines were fed the experimental diets for 35 days until they reached the market weight of 110 kg. The animals were assigned to the four experimental diets: control diet containing 5.00% tallow, T1 containing 5.00% hemp seed oil (hemp seed oil 40:soybean oil 60), T2 containing 5.00% evening primrose oil (primrose oil 40:soybean oil 60) and T3 containing 5.00% borage oil (borage oil 40:soybean oil 60). The plasma triacylglycerol and total cholesterol content of the swine in the gamma fatty acids-fed groups were significantly (p<0.05) lower than those in the control group. No gamma linolenic acid was detected in the plasma of the control group, while tile level of gamma linolenic acid treatment groups was significantly (p<0.05) higher than the control in the order of T3, T2 and T1. Moreover, the level of gamma linolenic acid increased with increasing number of feeding days. There was a significant difference between the treatment groups (p<0.05). There was a difference in the amount of saturated fatty acid and polyunsaturated fatty acid accumulated in the pork according to the treatment groups or the parts of the pork meat. The level of n-3 fatty acid of pork was highest in T1, which had been fed the hemp seed oil, followed in order by T3 and T2 (p<0.05). The content of gamma linolenic acid in pork was highest in T3, which had been fed the borage oil, followed in order by T2 and T1 (p<0.05). In particular, the level of gamma linolenic acid in pork increased in the order of the back fat, pork belly, ham and loin.

• Food Science of Animal Resources
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• v.26 no.1
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• pp.9-14
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• 2006

The aim of this study was to determine the chemical traits of duck meats with different rearing periods(45 70 days). The content of protein was 21.3 and 19.61% in the breast and leg at 70 days post hatched, respectively. Group at 70 days showed high protein composition than those of 45 days group. The content of fat was slightly increased with the rearing periods. The composition of Ca, mineral compound, was not showed the difference between leg and breast meat. However, it was increased with the rearing periods. The composition of Fe was not significantly different in the breast meat. However, there was a significant increase in the leg (p<0.05). It was compared 14.6 ppm at 45 days group to 27.5 ppm at 70 days group. The content of methionine was significantly increased in the breasts due to the increasing rearing periods (p<0.05), but not in leg meat. There was no significant difference between parts, but glutamic acid content was significantly decreased along with the increasing rearing periods (p<0.05). The content of collagen at 70 days(0.77 g/100 g) was higher than those of 45 days(0.65 g/100 g). It was affected by the rearing periods In the wing-removed skit, it was 0.15 g increases at 70 rearing period group. The cholesterol content was significantly increased in the leg but not in the breast. With the rearing periods, it was significantly increased in the leg (p<0.05).