• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.270-273
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• 2008

The point of the meaning, this study selects population which is aged over 65 and new silver generation who is aged between 55 to 64. The objects were selected by purposeful sampling method and the 933 objects who participated in leisure sports age over 55 were used for this thesis's analysis. The results of the study were as follow; First, the weekly participation frequency was physical psychological burden, facilities, information technology, interpersonal relations, concern lack, time lack, bear. there was statistically significant difference. Second, the daily workout time was physical psychological burden, facilities, information technology, interpersonal relations, concern lack, time lack, bear. there was statistically significant difference. Third, the participant experience was physical psychological burden, facilities, information technology, interpersonal relations, concern lack, time lack, bear. there was statistically significant difference.

• Smart Structures and Systems
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• v.24 no.2
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• pp.173-182
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• 2019

Due to the degradation of beamforming properties at angles close to $0^{\circ}$ to $180^{\circ}$, linear array does not have a complete $180^{\circ}$ inspection range but a smaller one. This paper develops a improved sensor array with two additional sensors above and below the linear sensor array, and presents time difference and two dimensional multiple signal classification (2D-MUSIC) based impact localization for omni-directional localization on composite structures. Firstly, the arrival times of impact signal observed by two additional sensors are determined using the wavelet transform and compared, and the direction range of impact source can be decided in general, $0^{\circ}$ to $180^{\circ}$ or $180^{\circ}$ to $360^{\circ}$. And then, 2D-MUSIC based spatial spectrum formula using uniform linear array is applied for locate accurate position of impact source. When the arrival time of impact signal observed by two additional sensors is equal, the direction of impact source can be located at $0^{\circ}$ or $180^{\circ}$ by comparing the first and last sensor of linear array. And then the distance is estimated by time difference algorithm. To verify the proposed approach, it is applied to a quasi-isotropic epoxy laminate plate and a stiffened composite panel. The results are in good agreement with the actual impact occurring position.

• Korean Journal of Exercise Nutrition
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• v.14 no.2
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• pp.95-101
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• 2010

The purpose of this study was to evaluate changes of body composition, cardio-respiratory function in ventilation threshold (VT) and maximal state exercise, systolic (SBP) and diastolic blood pressure (DBP) and serum nitric oxide (NO) production during acute reducing salt (RS) supplementation in college elite athletes. Variables of cardio-respiratory function during rest, ventilation threshold and maximal exercise was not shown a significantly difference between RS supplementation and non-supplementation, there was shown a significant increase in ventilation threshold time (p<0.05) and exhaustion time (p<0.05) during RS supplement compared to non-supplement. SBP and DBP were not shown a significant difference between RS supplement and non-supplement. This result suggests that acute intake of RS is not increased a blood pressure. Serum NO production was not significant difference in the RS supplement group, but it was shown a significantly increased levels (p<0.01, vs. recovery 30 min.) immediately after maximal exercise in the non-supplement group. This result suggests that acute intake of RS have important role in inhibition of serum NO production during maximal exercise. Conclusively, This study suggest that acute intake of RS was not influence in body composition variables, but it was positive effect in ventilation threshold time, exhaustion time, maintenance of blood pressure and inhibition of serum NO production in maximal treadmill exercise.

• Journal of Korean Physical Therapy Science
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• v.30 no.3
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• pp.41-48
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• 2023

Background: This study examined the effects of the bridge exercise with trunk rotation on the thickness of body trunk muscles, including external oblique, internal oblique, and transverse abdominis in healthy male adults. Design: Randomized controlled trial Methods: Twenty-four men were evenly divided into a trunk rotation bridge exercise group and a basic bridge exercise group by drawing lots. The two groups performed the respective exercise for thirty minutes, three times a week for six weeks. repeated measure analysis of variance (ANOVA) was used after distinguishing between three different time points before the experiment, three weeks after the experiment, and six weeks after the experiment. The significance level was set at 0.05. In case an interaction between time and group existed, the paired t-test was used to examine the within-group difference. The independent-sample t-test was used to check the between-group difference. The significance level was set at 0.05. Results: All the men showed a significant change over time in their external oblique, internal oblique, and transverse abdominis muscles. An interaction between time and group was also found (p<0.05). Conclusion: The bridge exercise with trunk rotation causes a meaningful difference in the thickness of external oblique, internal oblique, and transverse abdominis muscles. Therefore, this study proposes the use of this exercise for lower-back stabilization in future research and clinical settings.

• Geophysics and Geophysical Exploration
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• v.22 no.2
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• pp.56-61
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• 2019

In this paper, we studied efficient modeling strategies when we simulate the 3D time-domain acoustic wave propagation using a cell-based finite difference method which can handle the variations of both P-wave velocity and density. The standard finite difference method assigns physical properties such as velocities of elastic waves and density to grid points; on the other hand, the cell-based finite difference method assigns physical properties to cells between grid points. The cell-based finite difference method uses average physical properties of adjacent cells to calculate the finite difference equation centered at a grid point. This feature increases the computational cost of the cell-based finite difference method compared to the standard finite different method. In this study, we used additional memory to mitigate the computational overburden and thus reduced the calculation time by more than 30 %. Furthermore, we were able to enhance the performance of the modeling on several media with limited density variations by using the cell-based and standard finite difference methods together.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.1
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• pp.75-87
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• 2012

We investigated the physicochemical properties, pasting characteristics on the rapid visco analyzer, dough characteristics on a mixograph, product characteristics, and attributes of color and hardness of products made from a wheat bagel premix and rice bagel premix according to storage period and temperature. The pH and moisture content of stored rice bagel premix and wheat bagel premix, significantly decreased, depending on the storage temperature and time. The average of water retention capacity, alkaline water retention capacity, sedimentation value, and pelshenke value all significantly decreased temperature increases and increasing storage time. he initial pasting temperature and breakdown depending on the storage temperature and time showed a significant difference, but peak viscosity and setback with increasing storage time and temperature were not significantly different. The initial pasting temperature did not significantly affect the rice bagel premix. The midline peak time and band at 8 min of mixing time of the wheat bagel premix and rice bagel premix did not differ significantly. In product attributes, the cost of wheat bagel premix rice bagel premix and the L, a, and b value in color of wheat bagel premix showed significant difference. The hardness of wheat bagel premix according to storage time and the hardness of rice bagel premix depending on storage temperature significant difference. Therefore, storage time and temperature of wheat bagel premix and rice bagel premix and does not show significant differences. merchant can get regular and consistent, it is expected to lead to the promotion of rice consumption. Futhermore, research on better method to improve it's characteristics instead of wheat bagel premix is expected to.

• Women's Health Nursing
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• v.4 no.1
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• pp.5-35
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• 1998

This study attempted to determine the relation between the maternal role strain and their husbands' support in employed and nonemployed first-time mothers, and how it changed over time. A descriptive, longitudinal and comparative study design was conducted to collect and analyzed the data at three times(at 3-4days, at 4-6wks and at 3-month postpartum) regarding the change of maternal role strain and their husbands' support in employed and nonemployed first-time mothers. The subjects were 133 first-time mothers who delivered vaginally at K university hospital in Deagu, Korea from Dec., 1994 to Oct., 1995. Among these 58 were employed and 75 were nonemployed first-time mothers. This instruments used to data collection in this study were by Hobbs(1968 : The Difficulty Index for First-time Parents), Staffensmeier(1982: Transition Difficulty Measure), Tayer(1976: Emotional Support from Husband), Lee, Hae Kyoung(1992 : Physical Support from Husband). The analysis of data was done with SAS/PC program which included percentage, $x^2$-test, Pearson correlation, Repeated Measure ANOVA, Time Contrast Analysis and t-test. The results were as follows : 1. There was a significant negative correlation only at 3-4days(r=-.19, P=.0265) and at 4-6wks postpartum(r=-.18, P=.0392) between maternal role strain and husband's support of the first-time mothers. Thus, the more support from husband, the less maternal role strains the first-time mothers felt. Therefore, the 1st hypothesis that "the more husband's support the first-time mother felt at all the time of testing, the less maternal role strains they got" was partially supported at 3-days and 4-6 weeks postpartum. There was no correlation between maternal role strain and t husband's support of the employed first-time mothers at al testing times(at 3-4days postpartum : r=-.95, P=.9548, at 4-6wks postpartum : r=-.0960, P=.4733 and at 3-month postpartum : r=-.05, P=7306). On the contrary, the unemployed first-time mothers felt less maternal role strain when they received more support from their husband at 3-4 days postpartum(r=-.31, P=.0073) and at 4-6wks postpartum(r=-.23, P=.0490). 2. There was no difference of maternal role strain between two groups with regards to employment status(F=.97, P=.3270). But the maternal role strains of two groups were changed differently each other over time(F=3.89, P=.00234). Therefore, the 2nd hypothesis that "there was the difference in the maternal role strains with regard to employment status and over time" was rejected. 3. There was no difference in husband's support between the employed and the nonemployed first-time mothers(F=3.06, P=.0826). But there was a significant interaction between employment status and over time(F=3.64, P=.0267), so the support from husband of the employed and the unemployed first-time mothers was changed differently each other over time. The support from husband of the employed first-time mothers was lowered significantly and continuously at 4-6wks (F=5.20, P=.0263) and at 3-month postpartum(F=6.47, P=.0137) than at 3-4 days postpartum. On the contrary, there was no difference in change of husband's support of the employed first-time mothers between the 3-4 days and the 4-6wks postpartum(F=1.70, P=.1962) and between the 3-4 days and the 3-month postpartum(F=.21, P=.6513). Mean husband's support of the nonemployed first-time mothers was raised at 4-6wks postpartum than at 3-4 days postpartum but lowed at 3-month postpartum. The support form husband of both groups was tending downwards at 3-month postpartum than at 4-6wks postpartum, but the one between two groups was changed differently each other over time. The husband's support of the employed first-time mothers(M${\pm}$SD=64. 26${\pm}$8.63) was higher than the one of the nonemployed first-time mothers(M${\pm}$SD=59.16${\pm}$11.11) (t=-2.98, P=.0035), so the 3rd hypothesis that "there was the difference in the husband's support with regard to employment status and over time" was supported. On the basis of these conclusions, the following suggestion is proposed. This study examined the change and relationship between maternal role strain and husband's support in the employed and the nonemployed first-time mothers. So the further study regarding the comparison between the employed and the nonemployed multiparas is necessary.

• Journal of the Korean Wood Science and Technology
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• v.22 no.3
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• pp.45-50
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• 1994

This experiment was to investigate the effects of UV radiation and chemical treatments on the color difference in antioxidant (Tris(2,4-di-t-butyl phenoxy) phosphite)-containing polyurethane coats. The results obtained were summerized as follows: 1. The color difference increased as the exposure time of UV radiation increases, but decreased as addition level of antioxidant increaes. 2. After 400 hours exposure to UV radiation, the color difference respectively showed 6.13 and 5.94 at 0.7 % and 1.0 % addition level but appeared more severe below 0.7 % addition level. Thus, antioxidant prevented discoloration effectively. 3. The color difference of films by chemical treatments increased after 8 hours. Color difference of films treated with 5 % acetic acid($CH_3COOH$), 30 % ethyl alchol ($CH_3CH_2OH$) showed 7.31 and 7.30 respectively. 1 % sodium hydroxide treatment showed 1.86 color difference after 8 hours.

• Journal of the Korean Society of Radiology
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• v.15 no.6
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• pp.891-897
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• 2021

With the development of Amyloid PET Tracer, the accuracy of Alzheimer's diagnosis can be improved through the identification of beta-amyloid neurites. However, the long image acquisition time of 20 minutes can be difficult for the patient. PET/CT scans are sensitive to patient movement and may partially affect test results. In this study, we studied the proper image acquisition time without affecting the quantitative evaluation of the image through the list mode acquisition method according to the time of the distribution of radioactive drugs in the body. The list mode includes information about time compared to the existing frame mode, and it is easy to analyze data because it can reconstruct images about the time that researchers want. The research method obtained a reconstructed image by time using a list mode of 5min frame/bed, 10min frame/bed, 15min frame/bed, and 20min frame/bed to compare the difference between signal-to-pons take ratio (SNR) and lesion-to-pons uptake ratio (LPR) and the difference in reading time to obtain an appropriate image. As a result of quantitative analysis, when measuring in list mode, SUVmean values decreased in 6 regions of interest as the image acquisition time increased, but showed the largest difference in 5 min/bed images, followed by 10 min/bed and 15 min/bed. As a result, the difference in SUVmean values decreased. Therefore, it was found that SUVmean values at 15 min/bed did not differ enough to not affect image evaluation. There was no difference in LPR values. As a result of the qualitative analysis, there was no change in the reading findings according to the PET image acquisition time and there was no significant difference in the qualitative analysis score of the image reconstruction according to time. As a result of the study, there is no significant difference between 15 min/bed and 20 min/bed images during the ¹⁸F-flutemetamol PET/CT test, so it can be said that it is clinically useful to reduce the image acquisition time selectively using 15 min/bed via list mode depending on the patient's condition.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.183-186
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• 2005

A two dimensional (2-D) finite-difference time-domain (FDTD) method based on a novel finite difference scheme is developed to eliminate the numerical dispersion errors. In this paper, numerical dispersion and stability analysis of the new scheme are given, which show that the proposed method is nearly dispersionless, and stable for a larger time step than the standard FDTD method.