• Genomics & Informatics
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• v.5 no.4
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• pp.168-173
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• 2007

In previous nuclear genomic association studies, Random Forests (RF), one of several up-to-date machine learning methods, has been used successfully to generate evidence of association of genetic polymorphisms with diseases or other phenotypes. Compared with traditional statistical analytic methods, such as chi-square tests or logistic regression models, the RF method has advantages in handling large numbers of predictor variables and examining gene-gene interactions without a specific model. Here, we applied the RF method to find the association between mitochondrial single nucleotide polymorphisms (mtSNPs) and diabetes risk. The results from a chi-square test validated the usage of RF for association studies using mtDNA. Indexes of important variables such as the Gini index and mean decrease in accuracy index performed well compared with chi-square tests in favor of finding mtSNPs associated with a real disease example, type 2 diabetes.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.5-9
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• 2001

In this paper, we propose the new audio watermarking method and can be used on line processing. Instead of the wavelet transform, we use the integer wavelet transform for the reduction of the computational load. The watermark associated with the chi-square distribution is inserted into the signal on the integer wavelet domain. When extracting the watermark, the spread spectrum methods are used with the coefficients associated with the covariance sequence. We show that the chi-square distribution is a good tool for the spread spectrum method on the wavelet domain. This watermarking technique may be used for the control of the electrical product which can be controlled with the hidden signals and can be moved according to the audible signals simultaneously.

• Journal of Information Processing Systems
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• v.12 no.4
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• pp.644-660
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• 2016

The real-time detection of malware remains an open issue, since most of the existing approaches for malware categorization focus on improving the accuracy rather than the detection time. Therefore, finding a proper balance between these two characteristics is very important, especially for such sensitive systems. In this paper, we present a fast portable executable (PE) malware detection system, which is based on the analysis of the set of Application Programming Interfaces (APIs) called by a program and some technical PE features (TPFs). We used an efficient feature selection method, which first selects the most relevant APIs and TPFs using the chi-square ($KHI^2$) measure, and then the Phi (${\varphi}$) coefficient was used to classify the features in different subsets, based on their relevance. We evaluated our method using different classifiers trained on different combinations of feature subsets. We obtained very satisfying results with more than 98% accuracy. Our system is adequate for real-time detection since it is able to categorize a file (Malware or Benign) in 0.09 seconds.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.9
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• pp.135-145
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• 2020

This paper provides the practical application of a linear shrinkage framework on Vietnam stock market. The cumulative data points observed in this analysis are 468 weeks from January 2011 to December 2019. All the companies listed on Ho Chi Minh City Stock Exchange (HOSE), except the companies under two years period from Initial Public Offering (IPO), are considered. The cumulative number of stocks picked is therefore 350 companies. The VNINDEX, which is the Vietnam Stock Index, is used as a reference index for shrinking to a single-index model. The empirical results show that the shrinkage of covariance matrix for portfolio optimization gives the promising results for the investors on Vietnam stock market. The shrinkage method helps the investors to produce the optimal portfolio in the sense of having higher profit with lower levels of risk compared to the portfolio of the traditional SCM method. Moreover, the portfolio turnover of shrinkage method is always kept at low magnitudes, and this makes the shrinkage portfolios save much transaction costs and reduce the liquidity risks in the trading process. In addition, the ability of shrinkage method in making profit is once again confirmed by the Alpha coefficient that achieves a high positive value.

• International Journal of Contents
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• v.13 no.4
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• pp.16-22
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• 2017

The purpose of this study was to investigate the daily life experiences of medical students and to explore gender differences in these experiences using the Experience Sampling Method (ESM) as the method. The instrument, the Experience Sampling Form (ESF), consisted of questions on the external and internal experiences of the respondents. Data were collected from 2,035 ESFs by 91 students (male=52, female=39) at three medical schools for one week. The data was analyzed using the statistical tests of the t-test and ${\chi}^2$ test. Activity places were significantly different by gender (${\chi}^2=16.576$, p=.001). Males spent more time in learning places such as schools, libraries, etc., whereas females spent their time in personal places, including their homes, dormitories, etc. Males undertook more learning activities than did females, and females undertook more social/leisure activities and basic life activities than did male students (${\chi}^2=18.753$, p=.001). They were in a learning place and performing learning activities. There were significant perceptual differences between males and females about their flow levels, competency levels, and difficulty levels, based on the activity type. These results can help us to understand the daily lives of medical students and can be useful in developing counseling programs and educational activities for students.

• Water for future
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• v.22 no.4
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• pp.441-451
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• 1989

Using the wave data by typhoons LEE, VERA, THELMA which gave great damages in the Korean penisula, the significant waves based on zero-up & down crossing and Tucker-Draper method are compared with those from the wave energy spectrum. And the histograms of individual waves obtained from zero-up crossing method are presented and compared with the Rayleigh, Weibull, Gluhovski, Ibrageemov and Goda distributions, and also the Chi-square goodness of fit test is applied to each theoretical distributions. It is shown that the significant wave heights by zero-up crossing method are very well agreed to those by energy spectrum method. The wave heights are found to well follow the Rayleigh and Goda distributions by the Chi-square test.

• Journal of Korean Academy of Nursing
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• v.38 no.1
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• pp.11-18
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• 2008

Purpose: This study was to determine whether the Sun-style 24 forms of Tai Chi exercise improve pain, stiffness, disability, knee joint motion, mobility, balance or falling. Method: Forty-six community-dwelling elderly subjects (mean age, $75.46{\pm}6.28$) voluntarily participated in an intervention group of either 24 forms of Sun-style T ai Chi for 60 min, 2 times per week for 12 weeks or a control group. A non-equivalent pretest-posttest design was used. Independent t-test and ANCOVA were used to examine group differences by using SPSS12.0. Result: The experimental group had significantly less pain (F=7.60, p=.008) and stiffness (t=-3.19, p=.003) than the control group. Also there were significant improvements in knee joint motion on the right knee (t=2.44, p=.019), left knee (t=2.30, p=.026), rising time (F=8.03, p=.07), balance on the left single leg test (t=2.20, p=.033), and fear of falling (t=-2.33, p=.024) in the Tai Chi exercise group. No significant group differences were found in disability and falls efficacy. Conclusion: The Sun-style 24 forms Tai Chi exercise is effective in decreasing pain, stiffness, fear of falling and it improves balance, rising time, and knee joint motion. We suggest a continuing long term intervention to decrease disability and increase efficacy concerning falls.

• Women's Health Nursing
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• v.13 no.1
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• pp.43-50
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• 2007

Purpose: There is a need to apply the Tai Chi program to help early mastectomy patients improve their upper limb functions and for the emotional state as well. Method: Participants were recruited at breast cancer centers of two general hospitals from February 17 to April 25, 2005. Twenty-five subjects in the experimental group and 23 subjects in the control group participated for 12 weeks. The Tai chi program consisted of breast cancer self management education and a Tai Chi exercise program. Range of motion of the shoulder joint was determined by the Uni-level inclinometer, and functional assessment of the shoulder was evaluated with the tool. Data was analyzed by SPSS 11. Results: The experimental group had significantly increased shoulder range of motion, especially in external rotation, upper limb function and emotional state compared with the control group after program for 12 weeks. Conclusion: This program makes it possible to be independent and have a positive everyday life. In addition, it can help keep a healthy lifestyle in mastectomy women.

• Korean Journal of Acupuncture
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• v.28 no.4
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• pp.177-198
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• 2011

Objectives : The purpose of this study is to examine the theory of mind and body practice in Dan-Jeon-Ju-Seon from the point of views of Taoism, Buddhism, and Oriental medicine. Methods : An ideological background and development of Dan-Jeon-Ju-Seon was first examined. Then, the definition of, other descriptions of, and various locations of, Dan-Jeon were investigated. In addition, the theory of Qi movement of Shui Sheng Huo Jiang (ascent of water Chi and descent of fire Chi) in Dan-Jeon-Ju-Seon was taken into consideration from perspectives on the thought of Taoist Nei Dan (internal alchemy) and Oriental medicine. Finally, the characteristics of mind and body practice in Dan-Jeon-Ju-Seon. Results & Conclusions : Dan-Jeon in Dan-Jeon-Ju-Seon consists of three parts, upper, middle, and lower Dan-Jeon, which is related to Jing (sperm, essence) Qi (breath, eneregy) Shen (spirit, intellect) of our body. Jing Qi Shen is a crucial part in our mind and body, mind and body are connected by energy, and the energy flow is possible by ascent of water Chi and descent of fire Chi. Ultimately, Dan-Jeon-Ju-Seon is a method of practice to keep one's mind and body healthy, and its purpose is to do timeless meditation in our daily lives regardless of time and place.

• Journal of muscle and joint health
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• v.12 no.1
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• pp.69-80
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• 2005

Purpose: The purpose of this study was to analyse the effects of Tai Chi on the muscle strength and flexibility. Method: 10 articles from Medline search of foreign journals(1981-2003) and 4 from Korean nursing journals (1981-2003) were surveyed. The research are analyzed according to research design, subjects, and dependent variables. Results: Research on Tai Chi Exercise increased rapidly in the 1990's. The experimental research design was more reported than the comparative design. The experimental design included; 21.4% one group pre-posttest design, 35.7% quasi-experimental design and 28.6% randomized design. Out of the subjects; 64.4% of papers were healthy older people, and 35.6% of papers were patients with osteoarthritis or rheumatoid arthritis. Style of Tai Chi was mostly used Yang or Sun form. Muscle strength was usually measured at lower extremity or grip strength. Classical Yang style or Long form was more effective to improve muscle strength. 75% of papers were significantly improvement in grip strength and 71.4% of papers in flexibility. Conclusion: To properly study the positive effects of Tai Chi exercise, it is suggested that meta analysis needs to be done to integrate the various results.