• Journal of radiological science and technology
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• v.43 no.2
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• pp.79-85
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• 2020

The influence of metal artifact in CT image depends on the type of metal materialsm, the reconstruction algorithm, and scan parameters. The presence of metal artifacts was quantitatively evaluated by applying the standard and MAR algorithms through the phantom study. In the change of tube voltage applied the standard algorithm, metal artifact decreased to 44.9% for 80 vs 120 kVp, 24% for 100 vs 120 kVp, while the image taken at 140 kVp increased the artifact by 19% compared to 120 kVp. When the tube current was increased from 100 to 300 mA, there was no significant difference in the CT value and noise. Black band and white strike artifacts occurred up to 65.9% in the adjacent ROI of the metal driver, whereas titanium screw produced lesser metal artifact than that of the metal driver. The combination of 120kVp or higher tube voltage-standard algorithm was effective in removing black band artifacts as well as white streak by high density materials. However, MAR reconstruction algorithm was useful in improving image quality under the environment of low kVp and high density materials, without increase of radiation exposure.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.1
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• pp.55-61
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• 2002

Real-time Internet multi-media services requires fast data transmission, QoS and IP multicast. MARS is proposed to support IP multicast in the ATM Networks based on Internet, and RSVP is proposed to guarantee QoS in the Internet which is originally based on only best-effort service. In this paper, we propose two mechanisms to support IP multicast service involving QoS support over the ATM networks with MARS architecture based on multiple MCSs. In the first mechanism, when an ATM host requests joining into a specific multicast group, the MARS selects a proper MCS among the multiple MCSs to minimize the average time of transfer delay between the sender and the group members. In the second mechanism, when the RSVP reservation message from group member arrive at the MARS, the MARS which can process the RSVP reservation message select again the MCS with using the MCS management table. Finally, we recommend the mechanism to keep the QoS of Internet service and to reduce the processing-overhead between MARS and MCS.

• Korean Journal of Community Nutrition
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• v.8 no.5
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• pp.689-698
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• 2003

The purpose of this study was to evaluate the relationship between the diversity of food intake and nutrient intake among Korean college students participating in a nutrition education class via the internet. The subjects were 796 college students throughout South Korea (278 males, 518 females). A 3 days dietary recall survey was conducted and results were analyzed using the Computer-aided Nutritional Analysis Program. Dietary variety was assessed by DDS (dietary diversity score), MBS (meal balance score), and DVS (dietary variety score). Dietary quality was assessed by NAR (nutrient adequacy ratio), and MAR (mean adequacy ratio). As the DDS, MBS and DVS increased, the NAR and MAR improved. The subjects with a DDS of above 4 or a MBS of above 10 or a DVS of above 11 met two-thirds of the Korean recommended dietary allowance for most nutrients. The DDS, MBS and DVS correlated positively and significantly with the NAR and MAR. Associations between the NAR and high levels of DVS were more positive than those between the NAR and the DDS. Based on these results, the food intake of these subjects was not adequate. Specially, the dietary intake of calcium and iron were not adequate. Therefore, dietary guidelines should be made considering nutritional characteristics so as to improve the intake from all of the major food groups and provide a variety of foods in their diets.

• Journal of Nutrition and Health
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• v.44 no.2
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• pp.140-151
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• 2011

Middle-school students (158 boys and 199 girls) and their mothers were asked about nutritional attitudes, nutritional knowledge, dietary habits, and food intake using a questionnaire to examine whether nutritional knowledge and dietary behaviors of mothers affected their children's dietary habits. Nutritional attitude scores (total, 15 points) and nutritional knowledge scores (total, 20 points) of girls were 11.24 and 16.13 points, respectively, which were significantly higher than 10.47 and 15.43 points for boys. Generally, mothers received higher points than their children for all scores surveyed, but the results were not significantly different between boys' mothers and girls' mothers. The mean nutrient adequacy ratio (MAR) was calculated from dietary nutrient intakes to assess overall quality of meals. The results showed that girls had a higher MAR than that of boys (0.89 vs. 0.86, p < 0.01). Relationships among variables were examined by Pearson's correlation coefficient within children and between children and their mothers. Significant positive correlations were observed between nutritional attitudes and knowledge in both boys and girls. In girls, positive correlations between nutritional attitudes and dietary habits, nutritional knowledge and dietary habits, and dietary habits and MAR were also sig-nificant. In boys, only dietary habits and MAR were correlated with those of their mothers. Nutritional attitudes, dietary habits, and the MAR of girls' mothers were significantly correlated with nutritional attitude, dietary habits and the MAR of girls. The results indicate that the influence of mothers on dietary behaviors of children was greater in girls than that in boys, suggesting that a gender-specific nutrition education program is needed for middle school students.

• Korean Journal of Community Nutrition
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• v.5 no.2
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• pp.297-306
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• 2000

In order to examine the relationship between the number of different foods consumed and nutrient intake, one-day food consumption were surveyed by 24-hour recall from a sample of 287 individuals(20-49 years) living in Daejon City. The number of consumed food items did not include seasonings except red pepper power, sugar, oil, and soybean paste when used in large amounts(DVS). The number, including all seasonings except salt and vinegar(DVSS), was also counted. Of the total subjects, 43.6%(DVS) or 39.0%(DVSS) consumed 18-23 daily different foods with an average of 20.2 or 22.9, respectively. As the DVS increased, daily intakes of total foods and most food groups were elevated. Cereals however were not changed and eggs were decreased with increasing DVS. Energy and nutrient intakes and their mean adequacy ratio(MAR) and index of nutritional quality(INQ) also show positive correlations with DVS. MAR equal to or greater than($\geq$) 0.75 was taken as a cut-off point for nutritional adequacy. In that case, the mean INQ was shown to be $\geq$1. MRI(10) for energy and 9 nutrients and MAR(3) for Ca, vitamin A, and riboflavin were estimated. Form a regression analysis, when MAR(10) was 0.75, the DVS and DVSS were assumed to be 19.6 and 22.2, respectively. And when MAR(3) was 0.75, the DVS and DVSS were assumed to be 31.6 and 34.6, respectively. However the subjects whose MAR(3) was 0.75(0.7-0.8) 23.8(DVS) or 26.6(DVSS) different foods in average, and their mean intakes of energy and all nutrients, except vitamin A, were ranged at 85-100% of the RDA. Of the 74 subjects who consumed DVS$\geq$24, 24 to 42 numbers took 〈75% RDA of Fe, Ca, riboflavin, and vitamin A. And five of 7 who consumed DVS$\geq$32 took $\geq$125%RDA of protein, which showed concerns of overnutrition in case of DVS$\geq$32. Form the above results it could be suggested that a daily intake of 24-32(or 28) of DVS or 27-35(or 31) of DVSS was recommendable for an optimal nutritional of all nutrients if the variety of food groups and sufficient intake of vitamin A and calcium were emphasized together.

• Journal of Life Science
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• v.9 no.2
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• pp.176-181
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• 1999

In order to understand molecular phylogenetics of silkworm (Bombyx mori), we analyzed the sequences of BmoMAR isolated from Bomhyx mori that is partial coding gene of transposase of mariner-like element(MLE). By pairwise comparing nucleotide sequences of BmoMAR with ten previously reported insect MLEs accessed in GeneBank, the average genetic distance was estimated to be 0.4840. The phylogenetics tree constructed from nine insect species except for human MLE(Hsmarl) by UPGMA method indicated that MLEs are divided into three clusters, and Drosophila mariutiana was independently subgrouped. Bombyx mori(BmoMAR) was subgrouped with microcaddishfly (Orthotrichia cristata), webworm(Atteva punctella), almond moth(Ephestia cautella), Hyalopora cecropia which we lepidoptera. Phylogenetics tree according to UPGMA principle, on the basis of informative nucleotide sequences of nine insect MLEs, indicated that Bombyx mori was more closely related to microcaddishfly(Orthotrichia cristata) and webworm (Atteva punctella) of lepidoptera. We suggest that insect MLEs are a useful key for studying molecular phylogenetics among intra species of insects.

• Resources Recycling
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• v.4 no.1
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• pp.52-59
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• 1995

Treating bulk superalloy scrap with molten zinc has been studled to facililate recycling and recovery- of cobalt.Superalloys investigated were the cobalt-base Mar-M-509 and X45 and the nickel-base Rene 80. Charges withZnlscrap ratlos of 1.5-6.5 were heated to 750-9002 far 1-7.5 hours in a nitrogen atmosphere. The moltenzinc dissolved superalloy scrap and zinc was removed by vacuum distillation at 850-Wk for 4-6 hours. Ithas been concluded that the optimum conditions of decomposition for Mar-M-509 and Rene 80 \"ere dissolutiontemperature of about 850k, Znlscrap ratlo of about 5, and dissalution time of about 5.5 hours. The zinc-treatedsuperalloy prouducts were friable and reacted rapidly with acid solutions. Leaching 9mm pieces of unalloyedMar-M-509 or Rene 80 with 5 times the stolchlometric amount oi 6N HCI at 90t ior 3 hours dissolved about1.5-7.270, while leachmg of the minus 20-mesh products dissolved about 89.0-93.0%.ved about 89.0-93.0%.

• Advances in materials Research
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• v.2 no.3
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• pp.141-153
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• 2013

Nanocrystalline Barium niobate ($BaNbO_3$) has been synthesized by a novel auto-igniting combustion technique. The X-Ray diffraction studies reveals that $BaNbO_3$ posses a cubic structure with lattice constant $a=4.071{\AA}$. Phase purity and structure of the nano powder are further examined using Fourier-Transform Infrared and Raman spectroscopy. The average particle size of the as prepared nano particles from the Transmission Electron Microscopy is 20 nm. The UV-Vis absorption spectra of the samples are recorded and the calculated average optical band gap is 3.74eV. The sample is sintered at an optimized temperature of $1425^{\circ}C$ for 2h and attained nearly 98% of the theoretical density. The morphology of the sintered pellet is studied with Scanning Electron Microscopy. The dielectric constant and loss factor of a well-sintered $BaNbO_3$ at 5MHz sample is found to be 32.92 and $8.09{\times}10^{-4}$ respectively, at room temperature. The temperature coefficient of dielectric constant was $-179pp/^{\circ}C$. The high dielectric constant, low loss and negative temperature coefficient of dielectric constant makes it a potential candidate for temperature sensitive dielectric applications.

• The Journal of Korean Society for Radiation Therapy
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• v.31 no.1
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• pp.25-32
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• 2019

Purpose: The size, shape, and volume of prosthetic appliance depend on the metal artifacts resulting from dental implant during head and neck treatment with radiation. This reduced the accuracy of contouring targets and surrounding normal tissues in radiation treatment plan. Therefore, the purpose of this study is to obtain the images of metal representing the size of tooth through MVCT, SMART-MAR CT and KVCT, evaluate the volumes, apply them into the proton therapy plan, and analyze the difference of dose distribution. Materials and Methods : Metal A ($0.5{\times}0.5{\times}0.5cm$), Metal B ($1{\times}1{\times}1cm$), and Metal C ($1{\times}2{\times}1cm$) similar in size to inlay, crown, and bridge taking the treatments used at the dentist's into account were made with Cerrobend ($9.64g/cm^3$). Metal was placed into the In House Head & Neck Phantom and by using CT Simulator (Discovery CT 590RT, GE, USA) the images of KVCT and SMART-MAR were obtained with slice thickness 1.25 mm. The images of MVCT were obtained in the same way with $RADIXACT^{(R)}$ Series (Accuracy $Precision^{(R)}$, USA). The images of metal obtained through MVCT, SMART-MAR CT, and KVCT were compared in both size of axis X, Y, and Z and volume based on the Autocontour Thresholds Raw Values from the computerized treatment planning equipment Pinnacle (Ver 9.10, Philips, Palo Alto, USA). The proton treatment plan (Ray station 5.1, RaySearch, USA) was set by fusing the contour of metal B ($1{\times}1{\times}1cm$) obtained from the above experiment by each CT into KVCT in order to compare the difference of dose distribution. Result: Referencing the actual sizes, it was appeared: Metal A (MVCT: 1.0 times, SMART-MAR CT: 1.84 times, and KVCT: 1.92 times), Metal B (MVCT: 1.02 times, SMART-MAR CT: 1.47 times, and KVCT: 1.82 times), and Metal C (MVCT: 1.0 times, SMART-MAR CT: 1.46 times, and KVCT: 1.66 times). MVCT was measured most similarly to the actual metal volume. As a result of measurement by applying the volume of metal B into proton treatment plan, the dose of $D_{99%}$ volume was measured as: MVCT: 3094 CcGE, SMART-MAR CT: 2902 CcGE, and KVCT: 2880 CcGE, against the reference 3082 CcGE Conclusion: Overall volume and axes X and Z were most identical to the actual sizes in MVCT and axis Y, which is in the superior-Inferior direction, was regular in length without differences in CT. The best dose distribution was shown in MVCT having similar size, shape, and volume of metal when treating head and neck protons. Thus it is thought that it would be very useful if the contour of prosthetic appliance using MVCT is applied into KVCT for proton treatment plan.

• Journal of Nutrition and Health
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• v.37 no.2
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• pp.132-142
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• 2004

Nutritional factors affecting bone mineral density (BMD) in the different age groups of Korean men were investigated to obtain baseline data for maintaining bone health. Information on diet and anthropometry was collected in 80 elementary school children, 83 high school students, 87 adults aged 25 to 35 years and 98 elderly people over 60 years of age. Data for food and nutrient intake were obtained by 24-hour recall method. BMDs of lumbar spine (L$_2$- L$_4$) and femoral neck were measured by dual energy x-ray absorptiometry. The relationship between BMD and nutritional factors were analyzed. In the femoral neck, 5.7% of adults was classified as osteopenia and 47.9% and 37.8% of the elderly were classified as osteopenia and osteoporosis. It was shown that plant protein, Ca, p, Fe, thiamin, riboflavin and vitamin C intakes were related with BMD in all age groups. As for the mean adequacy ratio (MAR) of nutrients, the lowest quartile group of BMD showed significantly lower MAR among children. The RDA percent of nutrients was a strong influential factor on BMD. Subjects who consumed below 75% of Korean RDA in energy, vitamin A, thiamin, and vitamin C showed lower BMD. Stepwise multiple regression analysis revealed that MAR in children, vegetable Ca in adolescents, and vitamin C in adults and elderly people were the highest influential factor on BMD. Therefore, the above results demonstrated that not only calcium but also other nutrients such as protein, iron, vitamin A, riboflavin, and vitamin C were necessary in order to keep the healthy bone status. In addition, although there were various dietary factors that influenced bone density, MAR was identified as the major factor that affected bone density. Thus, a balanced diet that includes all nutrients is necessary for a healthy bone density. (Korean J Nutrition 37(2) : 132-142, 2004)