• Journal of Industrial Technology
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• v.28 no.B
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• pp.101-109
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• 2008

In general, non-stationary or chaos time series forecasting is very difficult since there exists a drift and/or nonlinearities in them. To overcome this situation, we suggest a new prediction method based on multiple model TS fuzzy predictors combined with preprocessing of time series data, where, instead of time series data, the differences of them are applied to predictors as input. In preprocessing procedure, the candidates of optimal difference interval are determined by using con-elation analysis and corresponding difference data are generated. And then, for each of them, TS fuzzy predictor is constructed by using k-means clustering algorithm and least squares method. Finally, the best predictor which minimizes the performance index is selected and it works on hereafter for prediction. Computer simulation is performed to show the effectiveness and usefulness of our method.

• Journal of Korean Physical Therapy Science
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• v.24 no.3
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• pp.64-71
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• 2017

Purpose: This study was investigated basic data for verifying the effect of rope skipping exercise by comparing and analyzing the effects on the body composition of female students. Method: The subjects of this study were 12 female college students and the rope-skipping exercise program was conducted after the purpose and process of this study were explained and the consent of the subjects was obtained. And we used the body composition analyzer (Inbody 520, Korea) to measure before and after exercise of Body Mass Index (BMI), Percentage Body Fat (PBF) and Waist Hip Ratio (WHR). Result: First, the daily living group and the rope-skipping exercise group showed a significant difference in the BMI according to the period and there was no significant difference between the groups. Second, in the PBF, there were no significant differences in the duration, interaction between duration and group and differences between the groups. Third, in the WHR, there were no significant differences in the duration, interaction between duration and group and differences between the groups. Conclusion: BMI of each group according to the period was significantly different between before exercise and 6 weeks after exercise.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.2
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• pp.109-117
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• 2023

Purpose : Transcranial direct current stimulation is noninvasive method of cerebral cortical stimulation applied as an intervention to facilitate recovery in stroke patients. The purpose of this study was to examine the effects of transcranial direct current stimulation on depression and anxiety in stroke patients with the aim to finding a reliable method to reduce depression and anxiety in stroke patients. Methods : This study was conducted at A hospital located in D city from December 2022 to February 2023. Patients diagnosed with stroke were selected according to predefined study criteria and divided into two groups. 9 patients in experimental group underwent transcranial direct current stimulation and traditional occupational therapy, while 9 patients in the control group underwent sham transcranial direct current stimulation and traditional occupational therapy for 20 min per session 3 times per week for a total of 8 weeks. Beck depression inventory (BDI) and Beck anxiety inventory (BAI) were used to evaluate depression and anxiety in the patients before and after intervention. Wilcoxon signed rank test was used to compare differences before to after intervention. Mann-Whitney U test was used to compare the two groups. Differences with p<.05 were considered statistically significant. Results : First, both the experimental and control groups presented significant statistical difference before and after intervention on depression (p<.01). Comparison of two groups after intervention showed significant statistical difference in depression (p<.05). Second, the groups presented significant statistical difference before and after intervention on anxiety (p<.01). After intervention, the two groups showed significant statistical difference in anxiety (p<.05). Conclusion : Results of the present study demonstrated the effects of transcranial direct current stimulation on depression and anxiety in stroke patients, suggesting it may be a useful method of rehabilitation in this patient population; as such, further studies are warranted.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.2
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• pp.284-290
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• 2012

This paper addresses a new passive target tracking problem using the range differences measured by cooperative UAVs. In order to solve the range difference based passive target tracking problem within the framework of linear robust state estimation, the uncertain linear measurement model which contains the stochastic parameter uncertainty is derived by using the noisy range difference measurements. To cope with the performance degradation due to the stochastic parameter uncertainty, the recently developed non-conservative robust Kalman filtering technique [1] is applied. For the cruciform formation flying UAVs, the relationship between the target tracking performance and the measurement errors is quantitatively analyzed. The proposed filter has practical advantages over the classical nonlinear filters because, for its recursive linear structure, it can provide satisfactory convergence properties and is suitable for real-time multiple UAVs applications. Through the simulations, the usefulness of the proposed method is demonstrated.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.9
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• pp.1064-1072
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• 1999

The well-known Dimension Exchange Method(DEM) to quantized loads may result in difference in assigned loads to processors as large as logn~units, in the worst case, after balancing for a hypercube of size n. In order to limit the increase of the accumulation of these differences, this paper proposes a method that limits the accumulation of the difference by redistributing an unit load (odd or even) of the same type, if possible, when there is a load distribution between two processors. We reduced the maximum difference to LCEIL logn over {2} RCEIL . The result shows the simulation experiments which show about 30% improvement in speedup compare to the DEM.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.6
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• pp.1-8
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• 1994

In this paper, in order to apply the idea MDPSK to TCM, we use signal set expansion and set partition by phase differences. Through this we propose the trellis-coded MDPSK. And the Viterbi decoder containing branch metrics of the squared Euclidean distance of the Lth order phase difference as well as the first order phase difference is introduced in order to improve the bit error rate(BER) in the differential detection of the trellis-coded MDPSK. The proposed Viterbi decoder is conceptually same to the sliding multiple symbol dection method which uses the branch metric with the first and Lth order phase differences. We investigate the performance of the uncoded DQPSK and the trallis-coded D8PSK in additive white Gaussian noise (AWGN) through the Monte Carlo simulation under the two cases of using and not using the Lth order phase difference metric. The study shows that trellis-coded 8DPSK is an attractive scheme for power and bandlimited systems while also improving the BER performance when the Viterbi decoder is employed to the Lth order phase order difference metric. This performance improvement has been obtained without sacrificing the bandwidth or the power efficiency.

• Journal of The Korean Society of Integrative Medicine
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• v.4 no.3
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• pp.1-15
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• 2016

Purpose : The purpose of this study was to evaluate the difference of early muscle strengthening exercise(starting at 1 week) on pain, function and sleep quality for rotator cuff partial tear patients. Method : Experimental group 15 people, control group 15 people, was a total of 30 people. Group-specific arbitration method, was applied to early muscle strengthening exercise (experimental group) and general movement treatment(Starting at 6 week) (control group). Both groups were subjected to 40 minutes of basic physical therapy interventions four times a week over an six-week intervention period. In this study, Pain, function and sleep quality measured by VAS, PPT and ROM, CMS, SST and PSQI. Result : 1. The VAS and PPT in the experimental group and control group before and after treatment were significant difference(p<.01). Comparison between the two groups in the change in motion before and after treatment also showed a statistically significant(p<.01). 2. Comparison functional Assessment of the shoulder ROM, CMS and SST in the experimental group and control group before and after treatment were significant difference(p<.01). ROM was not significant differences between the groups but CMS and SST were significant differences between the groups. 3. PSQI in the experimental group and control group before and after treatment were significant difference(p<.01). Comparison between the two groups in the change in motion before and after treatment also showed a statistically significant(p<.01). Conclusion : Therefore, early muscle strengthening exercise is useful to improve the shoulder function and pain for rotator cuff tear patients.

• Journal of Distribution Science
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• v.13 no.1
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• pp.47-55
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• 2015

Purpose - The objective of this study is to verify whether there are differences between Korean and Chinese consumers in the importance of the attributes such as shopping value and loyalty in social commerce. With the purpose of finding out these differences, the following questions are set up as research questions. First, will there be a difference between Korea and China in the importance of attributes of social commerce? Second, will there be a difference between Korean and Chinese consumers in shopping value? Third, will there be a difference between Korean and Chinese consumers in their loyalty? Research design, data, and methodology - The researchers collected data through self-administered questionnaires from Korean and Chinese consumers who had used social commerce within the past six months before answering the questionnaire. First, for social commerce users in Korea, comprising male and female university students in Chungcheong, a questionnaire was circulated. For social commerce users in China, university students within Beijing were surveyed. Responses to 336 questionnaires were used, excluding those with no answers or unreliable answers. Data coding and data cleaning were used. SPSS 18.0 was used. First, exploratory factor analysis is done to verify the validity of testing tools, and Cronbach's α coefficient is used to verify credibility. For factor analysis, the Varimax method is used. To verify the internal consistency reliability of each factor, the Cronbach's α coefficient is used to verify the credibility. Second, a T-test is done to verify differences between Korean and Chinese consumers for the importance of attributes. Third, ANOVA (Analysis of variance) is done to verify differences between Korean and Chinese consumers in shopping value and loyalty. Results - When Korean and Chinese consumers use social commerce, first, the importance of the attributes of social commerce is affected by four factors; playfulness and economic factors are more important to Korean consumers than Chinese consumers. As for informativeness factors, including product information and quality, and buyer comments, there was no confirmed difference between Korean and Chinese consumers. The convenience factor is more important to Chinese consumers than Korean consumers. Second, the factors affecting shopping value for Korean and Chinese consumers were hedonic shopping value and rational shopping value. To see the difference between Korean and Chinese consumers in shopping value factors, a t-test is conducted. As a result, in the rational shopping value factors of social commerce, Korean consumers scored higher than did Chinese consumers. These results were verified to be meaningful through statistics. In the hedonic shopping value factor of social commerce, Korean consumers scored higher than Chinese consumers. These results showed a significant difference. Third, loyalty in social commerce is higher for Chinese consumers than for Korean consumers. However, there is no difference in loyalty depending on sex. Conclusion - These results will hopefully be valuable and used in the future by Korean companies that wish to enter the Chinese social commerce market.

• Journal of the Ergonomics Society of Korea
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• v.34 no.5
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• pp.363-375
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• 2015

Objective: This study aims to recognize the risk of current traffic systems and to investigate a method to decrease risk by doing exercise using an elastic-band and cognitive rehabilitation. Background: The existing traffic system usually focuses on the ordinary citizens, which may not be appropriate to the elderly. It may affect the cognition and walking speed of the elderly. This study tries to examine whether cognition and muscle training is appropriate to improve their vulnerability. Therefore this study will provide human ergonomics - based basic data in relation to the elderly to identify the risk of current signal system and to mitigate the risk. Method: A total of 30 elderly participants were divided into two groups: experimental and control groups. Experimental group (n=15) was trained to strengthen their muscles and to promote cognition, whereas control group (n=15) was not. The training was conducted twice a week for three weeks. To strengthen muscles, a yellow colored elastic-band was used, and a computer program for cognitive rehabilitation was used to develop cognition. In the experimental group, there were significant differences between pre and post exercises However, the control group didn't show any significant difference. The increase in cognition and walking speed was found in the experimental group, whereas there were no differences in the control group. Statistically there was no significant difference between the two groups. Results: The results of this study show that the exercise program using the elastic-band gave a positive effect on gait training thanks to the development of muscle power and balance. Conclusion: This study did not show any statistical difference or significant differences between the two groups, since time was restricted, we believe. Application: The results of the walking speed will help to prevent traffic collision.

• Journal of Labour Economics
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• v.41 no.4
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• pp.1-30
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• 2018

The 1995 tax reform in Korea has brought adjustment to the tax bracket, marginal tax rate, and tax deduction system which resulted in significant decrease in the income tax progressivity. In this paper we study the causal effect of the tax reform on male labor supply using difference-in-differences method. Using the data from Economic Active Population Survey (EAPS) and Daewoo Panel Data, we find about 1.5% increase in the hours worked of male wage workers.