• Journal of The Korean Society of Integrative Medicine
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• v.8 no.3
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• pp.143-151
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• 2020

Purpose: This study aimed to investigate the effect of single-leg stance training according to different support surfaces on walking speed and balance in patients with chronic hemiplegia. Methods: Twenty-two patients with chronic stroke were randomly categorized into an experimental group (11 patients) and a control group (11 patients). In the experimental group, single-leg stance training was performed on an unstable surface after 50 min of general physical therapy. In the control group, single-leg stance training was performed on a stable surface after 50 min of general physical therapy. All participants performed five sets of single-leg stance exercises per minute and rested for 3 min. The intervention was performed 5 times a week for 4 weeks, and each patient was evaluated using the Berg Balance Scale (BBS), Fugl-Meyer Assessment Scale (FMA), and difference in walking speed between the first and last day of the intervention. Results: Compared to baseline measurements, both study groups showed significant increases in FMA, BBS, and walking speed (p<.05) after the intervention. However, there was no statistically significant difference (p>.05) between the experimental and control groups. However, in the experimental group, the increases in FMA, BBS, and walking speed were 3.36 %, 9.50 %, and 7.71 %, respectively. In the control group, the increases in FMA, BBS, and walking speed were 2.39 %, 6.65 %, and 7.64 %. Conclusion: Single-leg stance training on different support surfaces could help improve walking ability and balance in patients with chronic hemiplegia.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.25 no.4
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• pp.296-311
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• 2021

Topological Data Analysis (TDA), a relatively new field of data analysis, has proved very useful in a variety of applications. The main persistence tool from TDA is persistent homology in which data structure is examined at many scales. Representations of persistent homology include persistence barcodes and persistence diagrams, both of which are not straightforward to reconcile with traditional machine learning algorithms as they are sets of intervals or multisets. The problem of faithfully representing barcodes and persistent diagrams has been pursued along two main avenues: kernel methods and vectorizations. One vectorization is the Betti sequence, or Betti curve, derived from the persistence barcode. While the Betti sequence has been used in classification problems in various applications, to our knowledge, the stability of the sequence has never before been discussed. In this paper we show that the Betti sequence is unstable under the 1-Wasserstein metric with regards to small perturbations in the barcode from which it is calculated. In addition, we propose a novel stabilized version of the Betti sequence based on the Gaussian smoothing seen in the Stable Persistence Bag of Words for persistent homology. We then introduce the normalized cumulative Betti sequence and provide numerical examples that support the main statement of the paper.

• Asia-Pacific Journal of Business
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• v.13 no.3
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• pp.183-208
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• 2022

Purpose - The main purpose of this study is to widely investigate the impact of recent pandemic crises on the synchronization of the world capital markets through 25 stock indices from major developed countries. Design/methodology/approach - This study collects 25 stock indices from major developed countries and the time period is between January 5, 2001 and February 24, 2022. The data sets used in the study include finance.yahoo.com and Investing.com.. The Granger causality analysis, unit-root test, VAR analysis, and forecasting error variance decomposition were hired in order to analyze the data. Findings - First, there are significant inter-relations among 25 countries around recent major pandemic crises(such as SARS, A(H1N1), MERS, and COVID19), which is consistent result with previous literature. Second, COVID19 shows much stronger impact on the world-wide synchronization than other pandemics. Third, the return volatility of each stock market varies, unit root tests show that daily stock index data are unstable while daily stock index returns are stable, and VAR(Vector Auto Regression) analyses presents significant inter-relations among 25 capital markets. Fourth, from the impulse response function analyses, we find that each market affects the other markets for short term periods, about 2~4 days, and no long term effect was not found. Fifth, Granger causality tests show one-side or two-sides synchronization between capital markets and we estimate, through forecasting error variance decomposition method, that the explanatory portions of each capital market on other markets vary from 10 to 80%. Research implications or Originality - The above results all together show that pandemic crises have strong effects on the synchronization of world capital markets and imply that these synchronizations should be carefully considered both in the investment decisions by individual investors and in the financial and economic policies by governments.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.4
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• pp.51-60
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• 2023

Purpose : The purpose of this study was to determine the effect of pelvic floor muscle exercise (PFME) on an unstable support surface on maximal inspiratory pressure (MIP), maximum expiratory pressure (MEP), and abdominal muscle thickness as a method for effective PFME. Methods : This study was performed on 22 subjects. They were matched and divided into two groups based on body mass index; the experimental group (EG) performed PFME on a foam roller (n= 11), the control group (CG) performed PFME on a stable support surface (n= 11). Kegel exercise was performed with 10 seconds of contraction, 10 seconds of relaxation, and 4 sets of 10 reps per set. Both of group executed the exercise 3 times a week for 2 weeks. MIP and MEP was measured using a spirometer. Abdominal muscle thickness was measured using ultrasound. The paired t-test was used to compare difference on each group and the comparison between groups was analyzed using the independent t-test. A significance level of α= .05 was used to verify statistical significance. Results : The EG showed a significant increase in the MEP (p<.05). The CG showed a significant increase in the MEP (p<.05). There was no significant difference in the two groups (p>.05). The EG showed a significant increase in the external oblique, internal oblique and transverse abdominis (p<.05). The CG showed a significant increase in the internal oblique (p<.05). There was no significant difference in the two groups (p>.05). Conclusion : Based on the results of this study, additional research should be conducted to correct the limitations of this study to confirm that PFME performed on a foam roller has a positive effect on respiratory muscle strength and abdominal muscle thickness.