• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.2
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• pp.45-52
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• 2002

An experimental investigation on the structure and dynamic behavior of two dimensional over-expanded air jets exiting into water was carried out. The hish speed digital video imaging and static pressure distribution measurement were made to characterize the structure and time-dependant behavior of the jets. Mach number at the jet exit was 2.0 and was slightly less than the value predicted by the ideal nozzle calculation. Variance of jet spreading angle at different stagnation condition was measured as a function of mass flow rate. Periodic nature of the air jet distortion in water was observed and the frequency of the repetition was approximately 5-6 Hz for all cases tested. Three characteristic length scales were defined to characterize jet structure. $L_1$, maximum width of the plume when the periodic instability occurs, $L_2$, width of the jet where secondary reverse flow entrained jet flow and $L_3$, distance from the jet exit to the location where entrainment of the secondary reverse flow occurs. The ratio of $L_1$ and $L_2$ decreased with increasing stagnation pressure, i.e. mass flow rate. $L_3$ increased with increasing stagnation pressure. The temporal behavior of static pressure measurements also showed peak around frequency of 5, which corresponds the frequency obtained by visual measurements

• Korean Journal of Plant Taxonomy
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• v.46 no.4
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• pp.361-370
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• 2016

An area comprising Juwangsan National Park and its adjacent mountains (southeastern Korean Peninsula) is a good model system for testing the effects of physical barriers to gene flows in plant populations. We predicted that plant species consisting of isolated populations are genetically more differentiated than those that are rather continuously distributed. Most populations of Sedum polytrichoides occur in four isolated valleys, and we assessed the genetic variability and structures using twelve allozyme loci in ten populations. We also compared the present results to earlier findings pertaining to the two co-occurring herbs Hylotelephium ussuriense (${\equiv}$ Sedum ussuriense) (growing only in the four isolated valleys) and S. kamtschaticum (rather continuously distributed). We found moderate levels of within-population genetic variation in S. polytrichoides ($H_{e}=0.112$). Estimates of among-population divergence in S. polytrichoides were also moderate ($F_{ST}=0.250$) and, as expected, very similar to that of H. ussuriense (0.261) but considerably higher than the variation in S. kamtschaticum (0.165). An analysis of molecular variance (AMOVA) revealed that S. polytrichoides and H. ussuriense had higher percentages of among-valley variation (19% each) than S. kamtschaticum (4%). Most of this variation, as also indicated by the STRUCTURE program, was due to differences in genetic profiles between the two central valleys. We concluded that the genetic differences observed between species (S. kamtschaticum vs. S. polytrichoides and H. ussuriense) are mainly due to differences in their distribution within the study area.

• International Journal of Advanced Culture Technology
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• v.9 no.1
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• pp.16-21
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• 2021

As the average age of national veterans has increased from 69 years old(2011) to 71 years old(since 2015) over the past five years, the overall medical service cost of veterans has increased by about 20%. The main cause of this phenomenon is 'ultra-aging', which accounts for 67% of veterans, while the proportion of health insurance patients aged 70 or older is 9%. Therefore, it is judged that the analysis of the trend of use of medical services at veterans hospitals in each region that is in charge of severe medical services of national veterans can serve as an opportunity to seek countermeasures for the severe medical system of national veterans. First of all, based on the details of major medical expenses (hospitalization, outpatient, pharmaceutical expenses) by region for the last 10 years(2010-2019), data significance was performed through a chi-square test, and the Central Veterans Hospital and Non-Central Veterans Hospital using EXCEL. 'Expected frequency' was calculated by year. By applying the CHITEST(observation frequency, expected frequency) function again, the p-value(p<0.05) was calculated, and the profit bias of each region's veterans hospital could be determined. The specific research method is for the last 10 years(2010-2019) for state-sponsored patients_outpatient treatment income, state-sponsored patients_hospitalization income, exempt patients_outpatients at the Central Veterans Hospital, Busan Veterans Hospital, Gwangju Veterans Hospital, Daegu Veterans Hospital, and Daejeon Veterans Hospital. A one-way analysis of variance was conducted to verify the significance of the difference between group averages on the status of 5 medical revenues of veterans hospitals in each of the 5 regions, including medical treatment income, reduced patients_hospitalization income, and reduced patients_medicine expenses. It was found to be significant(p<0.05) at all levels, including region and type. Finally, the bias in the profit structure of regional veterans hospitals was the highest in 2017(p=0.0004) and the lowest in 2013(p=0.0349). In addition, in the profit structure of the Veterans Hospital, the year in which the'regional' variable worked the most was 2019, and the year with the least affected was 2010. The order of the former is Jungang(=31,674,713), Busan(=12,314,614), Gwangju(=11,957,038), Daegu(=10,168,015), and Daejeon(=6,991,034), and the order of the latter is Jungang(=57,868,791), and Busan(=19,183,194). Gwangju(=17,904,712), Daegu(=15,656,034), and Daejeon(=14,377,395). In conclusion, the profit bias of veterans hospitals repeatedly raced the lowest(p=0.01986) and highest(p=0.03499) for the past five years(2010-2014) year by year, with the 'regional' variable being the most in the veterans hospital's profit structure It was identified as a major influence factor. On the other hand, for the last 5 years (2015-2019), the influence factors of the'regional' variable every year were in 2015(p=0.02015), 2016(p=0.01741), 2017(p=0.00045), and 2018(p=0.00394). in 2019(p=0.00227), a significant difference was confirmed at a very low level.

• Proceedings of the KACD Conference
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• 2008.05a
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• pp.177-183
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• 2008

It was reported that esthetic composite resin restoration reinforces the strength of remaining tooth structure with preserving the natural tooth structure. However, it is unknown how much the strength would be recovered. The purpose of this study was to compare the fracture resistance of three types of undermined cavity filled with composite resin with that of non-cavitated natural tooth. Forty sound upper molars were allocated randomly into four groups of 10 teeth. After flattening occlusal enamel. undermined cavities were prepared in thirty teeth to make three types of specimens with various thickness of occlusal structure (Group $1{\sim}3$). All the cavity have the 5 mm width mesio-distally and 7 mm depth bucco-lingually. Another natural 10 teeth (Group 4) were used as a control group. Teeth in group 1 have remaining occlusal structure about 1 mm thickness, which was composed of mainly enamel and small amount of dentin. In Group 2, remained thickness was about 1.5 mm, including 0.5 mm thickness dentin. In Group 3, thickness was about 2.0 mm, including 1 mm thickness dentin. Every effort was made to keep the remaining dentin thickness about 0.5 mm from the pulp space in cavitated groups. All the thickness was evaluated with radiographic Length Analyzer program. After acid etching with 37% phosphoric acid, one-bottle adhesive (Single $Bond^{TM}$, 3M/ESPE, USA) was applied following the manufacturer's recommendation and cavities were incrementally filled with hybrid composite resin (Filtek $Z-250^{TM}$, 3M/ESPE, USA). Teeth were stored in distilled water for one day at room temperature, after then, they were finished and polished with Sof-Lex system. All specimens were embedded in acrylic resin and static load was applied to the specimens with a 3 mm diameter stainless steel rod in an Universal testing machine and cross-head speed was 1 mm/min. Maximum load in case of fracture was recorded for each specimen. The data were statistically analyzed using one-way analysis of variance (ANOVA) and a Tukey test at the 95% confidence level. The results were as follows: 1. Fracture resistance of the undermined cavity filled with composite resin was about 75% of the natural tooth. 2. No significant difference on fracture loads of composite resin restoration was found among the three types of cavitated groups. Within the limits of this study, it can be concluded the fracture resistance of the undermined cavity filled with composite resin was lower than that of natural teeth, however remaining tooth structure may be supported and saved by the reinforcement with adhesive restoration, even of that portion consists of mainly enamel and a little dentin structure.

• Restorative Dentistry and Endodontics
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• v.33 no.3
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• pp.177-183
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• 2008

It was reported that esthetic composite resin restoration reinforces the strength of remaining tooth structure with preserving the natural tooth structure. However, it is unknown how much the strength would be recovered. The purpose of this study was to compare the fracture resistance of three types of undermined cavity filled with composite resin with that of non-cavitated natural tooth. Forty sound upper molars were allocated randomly into four groups of 10 teeth. After flattening occlusal enamel, undermined cavities were prepared in thirty teeth to make three types of specimens with various thickness of occlusal structure (Group $1{\sim}3$). All the cavity have the 5 mm width mesiodistally and 7 mm depth bucco-lingually. Another natural 10 teeth (Group 4) were used as a control group. Teeth in group 1 have remaining occlusal structure about 1 mm thickness, which was composed of mainly enamel and small amount of dentin. In Group 2, remained thickness was about 1.5 mm, including 0.5 mm thickness dentin. In Group 3, thickness was about 2.0 mm, including 1 mm thickness dentin. Every effort was made to keep the remaining dentin thickness about 0.5 mm from the pulp space in cavitated groups. All the thickness was evaluated with radiographic Length Analyzer program. After acid etching with 37% phosphoric acid, one-bottle adhesive (Single $Bond^{TM}$, 3M/ESPE, USA) was applied following the manufacturer's recommendation and cavities were incrementally filled with hybrid composite resin (Filtek $Z-250^{TM}$, 3M/ESPE, USA). Teeth were stored in distilled water for one day at room temperature, after then, they were finished and polished with Sof-Lex system. All specimens were embedded in acrylic resin and static load was applied to the specimens with a 3 mm diameter stainless steel rod in an Universal testing machine and cross-head speed was 1 mm/min. Maximum load in case of fracture was recorded for each specimen. The data were statistically analyzed using one-way analysis of variance (ANOVA) and a Tukey test at the 95% confidence level. The results were as follows: 1. Fracture resistance of the undermined cavity filled with composite resin was about 75% of the natural tooth. 2. No significant difference in fracture loads of composite resin restoration was found among the three types of cavitated groups. Within the limits of this study, it can be concluded the fracture resistance of the undermined cavity filled with composite resin was lower than that of natural teeth, however remaining tooth structure may be supported and saved by the reinforcement with adhesive restoration, even if that portion consists of mainly enamel and a little dentin structure.

• Korean Journal of Childcare and Education
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• v.10 no.3
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• pp.69-84
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• 2014

The purpose of this study was to examine the influence of educare teachers' science education knowledge and attitudes towards science on science teaching anxiety. 259 teachers of young children were recruited from 19 daycare centers and the data were analyzed through frequency, percentage, Pearson's correlations using PASW 18.0 and structure equation modeling using AMOS 7.0. The findings are as follows. First, educare teachers showed more than median scores in all science education knowledge, attitude towards science and science teaching anxiety. Second, in total 57% of the variance in teachers' science teaching anxiety was accounted for by teachers' science education knowledge and attitude towards science. This result implied that teachers' science education knowledge and attitude towards science should be improved in order to reduce teachers' science teaching anxiety.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12C
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• pp.1250-1257
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• 2003

Generally images are classified into two regions: edge and flat region. While low frequency components are popular in the flat region, high frequency components are quite important in the edge region. Therefore, deinterlacing algorithm that considers the characteristic of each region can be more efficient. In this paper, an image is divided into edge region and flat region by the local variance. And then, for each region, frequency modularized neural network is assigned. Using this structure, each modularized neural network can learn only its region intensively and avoid the complexity of learning caused by the data of different region. Using the local AC data for the input of neural network can prevent the degradation of the performance of teaming due to the average intensity values of image that disturbs the effective learning. The proposed method shows the improved performance compared with previous algorithms in the simulation.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.2
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• pp.169-178
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• 2014

Samples of Clitoria ternatea L. (Cunh$\tilde{a}$) were harvested at 35, 50, 70, and 90 d after a uniformity harvest in a field study designed as a completely randomized design with a total of 18 experimental plots. The dry matter yield of the whole plant was separated quantitatively into leaves, stems, and pods at each harvesting age. Chemical analyses and in vitro gas production kinetics were performed to assess the quality of the plant parts. Yields, chemical composition, and estimates of gas production parameters were analyzed by fitting a mixed statistical model with two types of covariance structures as follows: variance components and an unrestricted structure with heterogeneous variances. Fast and slow gas yielding pools were detected for both leaves and stems, but only a single pool was detected for pods. The homoscedasticity assumption was more likely for all variables, except for some parameters of the gas production kinetics of leaves and stems. There was no presence of typical pods at 35 and 50 d. In the leaves, the fibrous fractions were affected, whereas the non-fibrous fractions were unaffected by the harvesting age. The harvesting age affected the majority of the chemical constituents and gas kinetic parameters related to the stems. The leaves of this legume were the least affected part by the aging process.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.9
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• pp.1223-1228
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• 2012

The population sizes of three Korean indigenous cattle populations have been drastically reduced over the past decades. In this study, we examined the extent to which reduction in populations influenced genetic diversity, population structure and demographic history using complete mitochondrial DNA (mtDNA) control region sequences. The complete mtDNA control region was sequenced in 56 individuals from Korean Black (KB), Jeju Black (JEB) and Korean Brindle (BRI) cattle populations. We included 27 mtDNA sequences of Korean Brown (BRO) from the GenBank database. Haplotype diversity estimate for the total population was high (0.870) while nucleotide diversity was low (0.004). The KB showed considerably low nucleotide (${\pi}$ = 0.001) and haplotype (h = 0.368) diversities. Analysis of molecular variance revealed a low level of genetic differentiation but this was highly significant (p<0.001) among the cattle populations. Of the total genetic diversity, 7.6% was attributable to among cattle populations diversity and the rest (92.4%) to differences within populations. The mismatch distribution analysis and neutrality tests revealed that KB population was in genetic equilibrium or decline. Indeed, unless an appropriate breeding management practice is developed, inbreeding and genetic drift will further impoverish genetic diversity of these cattle populations. Rational breed development and conservation strategy is needed to safeguard these cattle population.

• Journal of Korean Academy of Nursing
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• v.45 no.3
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• pp.439-448
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• 2015

Purpose: The purpose of this study was to examine validity and reliability of Webel and colleagues'HIV Self-Management Scale when used with a Korean sample. Methods: The original 20-item HIV Self-Management Scale was translated into Korean using translation and back-translation. Nine HIV nurse experts tested content validity. Principal component analysis (PCA) and confirmatory factor analysis (CFA) of data from 203 patients was used to test construct validity. Concurrent validity was evaluated using correlation with patients'self-rating as a "mart patient"measured using a visual analogue scale. Internal consistency was tested by Cronbach' alpha coefficients. Results: All items were rated as having satisfactory content validity. Based on PCA and consideration of conceptual meaning, a three-factor solution was selected, explaining 48.76% of the variance. CFA demonstrated the adequacy of the three-domain structure of the construct HIV self-management: daily self-management health practices, social support and HIV self-management, and chronic nature of HIV self-management. Goodness-of-fit indices showed an acceptable fit overall with the full model (${\chi}^2/df_{(164)}=1.66$, RMSEA=0.06, SRMR=0.05, TLI=0.91, and CFI=0.92). The Korean version of the HIV Self-Management Scale (KHSMS) was significantly correlated with patients'self-rated smart patient (r=.41). The subscale Cronbach' alpha coefficients ranged from .78 to .81; alpha for the total scale was .89. Conclusion: The KHSMS provides a valid and reliable measure of self-management in Korean patients with HIV. Continued psychometric testing is recommended to provide further evidence of validity with this population.