• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.12
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• pp.776-780
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• 2015

In this paper, we have studied the effect of mechanical polishing to Ga-polar face for reducing the wafer bowing and strain in free-standing GaN. After the mechanical polishing to Ga-polar face, the bowing of the free-standing GaN substrate significantly decreased with increasing the size of diamond slurry, and eventually changed the bowing direction from concave to convex. Furthermore, the full width at half maximum (FWHM) of high-resolution X-ray diffraction (HR-XRD) were decreased, especially the FWHM of (1 0 2) reflection for $1.0{\mu}m$ size of diamond slurry was significantly decreased from 630 to 203 arcsec. In the case, we confirmed that the compressive strain in Ga-polar face was fully released by Raman measurement.

• The Journal of Korean Physical Therapy
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• v.23 no.4
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• pp.1-6
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• 2011

Purpose: We investigated the effects of single-leg stance training on standing balance and mobility in patients with subacute hemiplegia. Methods: Seventeen matched subjects were assigned randomly to the experimental group or the control group. The experimental group comprising of 8 subjects received single-leg stance training and conventional physical therapy interventions 5 times per week for 4 weeks. The control group comprising of 9 subjects received only conventional physical therapy interventions 5 times per week for 4 weeks. Outcome measures were assessed before and after 4 weeks of intervention using the Berg Balance Scale (BBS), gait speed, and weight bearing index of the affected side. Results: Both the exercise groups showed significant improvements in BBS, gait speed, and weight bearing index (p<0.05). After 4 weeks of intervention, there were statistically significant differences in BBS and weight bearing index between the two groups (p<0.05). Conclusion: These findings suggest that conventional physical therapy interventions along with single-leg stance training could be more effective than conventional physical therapy alone for improving standing balance and mobility in patients with subacute hemiplegia.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.1
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• pp.30-34
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• 2016

In this paper, we report that selective etching on N-polar face by EC (electro-chemical)-etching effect on the reduction of bowing and strain of FS (free-standing)-GaN substrates. We applied the EC-etching to concave and convex type of FS-GaN substrates. After the EC-etching for FS-GaN, nano porous structure was formed on N-polar face of concave and convex type of FS-GaN. Consequently, the bowing in the convex type of FS-GaN substrate was decreased but the bowing in the concave type of FS-GaN substrate was increased. Furthermore, the FWHM (full width at half maximum) of (1 0 2) reflection for the convex type of FS-GaN was significantly decreased from 601 to 259 arcsec. In the case, we confirmed that the EC-etching method was very effective to reduce the bowing in the convex type of FS-GaN and the compressive stress in N-polar face of convex type of FS-GaN was fully released by Raman measurement.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.2
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• pp.173-181
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• 2014

The propagation behavior and structural variation of a premixed propane/air flame with frequency change in an ultrasonic standing wave at various equivalence ratios were experimentally investigated using Schlieren photography and pressure measurement. The propagating flame was observed in high-speed Schlieren images, allowing local flame velocities of the moving front to be analyzed in detail. The study reveals that the distorted flame front and horizontal splitting in the burnt zone are due to the ultrasonic standing wave. Vertical locations of the distortion and horizontal stripes are intimately dependent on the frequency of the ultrasonic standing wave. In addition, the propagation velocity of the flame front bounded by the standing wave is greater than that of the flame front without acoustic excitation. As expected, the influence of the ultrasonic standing wave on premixed-flame propagation becomes more prominent as the frequency increases.

• The Korean Journal of Applied Statistics
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• v.24 no.6
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• pp.1139-1148
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• 2011

Team standings in the regular professional baseball league should be determined based on a reasonable criterion; however, an unreasonable Japanese method is being used in Korea as of 2011. In this paper, we suggest a new method of computing the percentage of victories constructed by combining the advantages of the methods to determine team standings used in Korean professional baseball. We also have applied preexistent methods and suggested method to past and present Korean professional baseball data.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.2
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• pp.161-168
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• 2015

An experimental study was conducted to scrutinize the influence of the frequency of an ultrasonic standing wave on the variation in the behavior of a methane-air premixed flame. The evolutionary features of the propagating flame were captured by a high-speed camera, and the macroscopic flame behavior, including the flame structure and local velocities, was investigated in detail using a post-processing analysis of the high-speed images. It was found that a structural variation and propagation-velocity augmentation of the methane-air premixed flame were caused by the intervention of the ultrasonic standing wave, which enhanced the combustion reaction. Conclusive evidence for the dependency of the flame behaviors on the driving frequency of the ultrasonic standing wave and equivalence ratio of the reactants is presented.

• Physical Therapy Rehabilitation Science
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• v.3 no.2
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• pp.125-133
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• 2014

Objective: The aim of this study is to investigate the effect of patellar taping on balance and gait abilities in chronic stroke patients. Design: Randomized placebo-controlled trial. Methods: Thirty chronic stroke patients who have been diagnosed at least six months or before were recruited from R hospital. These study subjects were randomized to the experimental group (n=15) or placebo group (n=15). In the experimental group, patellar taping was applied while for the placebo group, placebo taping was applied. The Balance System SD was used for measuring dynamic standing balance in these two groups. In addition, the GAITRite (CIR System Inc.) system was utilized for calculating gait performance in these patients. Results: After application of taping, the patellar taping group showed a significant decrease in dynamic standing balance in their sway area (p<0.05). However, in the placebo group, there was no significant difference in dynamic standing balance ability and gait ability before and after application of taping. Comparison of the patellar taping group and placebo group showed significant differences in dynamic standing balance ability and gait performance (p<0.05). Conclusions: From the results of this study, it appears that application of patellar taping in chronic stroke patients significantly improved dynamic standing balance ability and gait ability in these patients. Based on these results, patellar taping is thought to be useful in real clinical settings where there are many chronic patients who are in need of improvement in their balance and gait ability.

• Journal of Industrial Convergence
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• v.20 no.7
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• pp.1-11
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• 2022

In this paper, numerical values are derived using topic modeling among data-based evaluation methodologies discussed by various research institutes. In addition, we will focus on the ICT field to see if there is a difference in policy perception between the national R&D project and standing committee. First, we create model for classifying ICT documents by learning R&D project data using HAN model. And we perform LDA topic modeling analysis on ICT documents classified by applying the model, compare the distribution with the topics derived from the R&D project data and proceedings of standing committees. Specifically, a total of 26 topics were derived. Also, R&D project data had professionally topics, and the standing committee-discuss relatively social and popular issues. As the difference in perception can be numerically confirmed, it can be used as a basic study on indicators that can be used for future policy or project evaluation.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2004.05a
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• pp.98-112
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• 2004

Nowadays science and technology analyses appeared as standing on the basis of the scope and quantity of literature in the field of rapidly progressed science and technology. And using both of them, it is named 'bibliometric'\;or\;'scientometrics'. These analysis results answer emergence in science and technology and provide researchers, responsible persons, technological information specialists, and planners with useful value. Accordingly, the purpose of this research is to suggest schematized change aspects and new research directions hidden in bibliographical phenomenon of a paper in the science and technology field to science and technology researchers and policy planners. For this, the field this paper researche is the next generation OLED field. The reason to choose this field is due to the importance of the next generation OLED, and wide scope connected by various fields. Besides, to measure application and technological fields by using bibliographical method and technology is as important as in a basic research field.

• Safety and Health at Work
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• v.9 no.1
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• pp.79-83
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• 2018

Background: Lower-limb varicose veins (VVs) are common and known to have a higher prevalence among people who work in occupations requiring prolonged standing. In the Republic of Korea, however, VV-related occupational factors have seldom been examined. This study was conducted to assess the prevalence of VVs among nurses, an occupational group considered to be at high risk of VVs, and determine the occupational risk factors of prolonged standing. Methods: Between March and August 2014, a questionnaire survey coupled with Doppler ultrasonography was conducted on the nurses working at a university hospital. Results: A total of 414 nurses participated in the survey and diagnostic testing. From the survey analysis and test results, the prevalence of VVs in nurses was estimated to be 16.18%. Significant factors for venous reflux were age [odds ratio (OR) = 1.06, 95% confidence interval (CI) = 1.03-1.10], pregnancy (OR = 2.15, 95% CI = 1.17-3.94), and delivery (OR = 2.02, 95% CI = 1.08-3.78). The statistical significance of these factors was verified after risk adjustment for sociodemographic factors (OR = 3.40, 95% CI = 1.27-9.09). Conclusion: Factors significantly associated with venous reflux were increasing age and prolonged working hours (${\geq}4hours$) in a standing position (OR = 2.80, 95% CI = 1.08-7.25), even after risk adjustment for sociodemographic factors. This study is significant in that an objective diagnosis of VVs preceded the analysis of the risk factors for VV incidence, thus verifying objectively that VVs are associated with occupations requiring prolonged hours of working in a standing position.