• Title/Summary/Keyword: difference in difference

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LYAPUNOV FUNCTIONS FOR NONLINEAR DIFFERENCE EQUATIONS

  • Choi, Sung Kyu;Cui, Yinhua;Koo, Namjip
    • Journal of the Chungcheong Mathematical Society
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    • v.24 no.4
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    • pp.883-893
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    • 2011
  • In this paper we study h-stability of the solutions of nonlinear difference system via the notion of $n_{\infty}$-summable similarity between its variational systems. Also, we show that two concepts of h-stability and h-stability in variation for nonlinear difference systems are equivalent. Furthermore, we characterize h-stability for nonlinear difference systems by using Lyapunov functions.

The sexual awareness and sexual behaviour of high school students (고등학생의 성 의식과 성 행동에 관한 연구)

  • Oh, Hyun-Mee;Park, Young-Soo
    • The Journal of Korean Society for School & Community Health Education
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    • v.2 no.2
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    • pp.89-99
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    • 2001
  • This paper is based on the assumption that the sexual awareness and sexual behaviour of high school students would show the difference between an academic high school and a vocational high school. The main purpose of this paper is to provide basic information on establishing the direction of a realistic and efficient education, which leads to the desirable sex ethics eventually. To do this, a comparative study was carried out to figure out the difference between academic high school students and vocational high school students in terms of their actual awareness and behaviour of sex. I put the following two questions in order to achieve the goal of this study. First, what is the difference in sexual awareness between academic high school students and vocational high school students? Second, what is the difference in sexual behaviour between academic high school students and vocational high school students? The subjects of the survey conducted were 595 high school students in Kyunggi Province and I made the questionnaires referencing pre-studies. The SPSS program was used to get a frequency and a percentage from the results of the survey and then, by applying t-text, $x^2$ verification and interrelation, the following results were obtained. First, regarding sexual awareness, there wasn't much difference in their idea of keeping virginity before marriage between academic high school students and vocational high school students. From the results obtained by analyzing the interrelation between students and their parents and friends in terms of a will to keep virginity, it is found that there was a relevance in both academic high school and vocational high school. When they have a sex problem, it was friends that they are looking for consulting and both groups showed thesame result. But pertaining to an experience of a sex education, the comparative analysis indicated an meaningful difference. Second, as for sex behaviour, it was shown that there was a difference in the experience of going out with the other sex between academic high school students and vocational high school students as well as in the degree of physical touch. However, not much difference was shown in controlling a sex desire between the two groups. As a results of the comparative analysis of the sex experience between the two groups, there was a meaningful difference. In terms of the object of their sex experience, the majority of students in the two groups chose a friend as their first answer and there was little difference. From these results I can draw some conclusions that most of the students in both groups have a link with friends and parents in keeping their virginity. Furthermore, a meaningful difference in experiencing a sex education is presented between the two groups. With regard to the sex behaviour of high school students, a meaningful difference is shown in dating the other sex, a physical touch and a sex experience between the two groups. Consequently, we realize that there is a meaningful difference in some variants on the sexual awareness and sexual behaviour of high school students between academic high school and vocational high school.

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Time-Dependent Optimal Heater Control Using Finite Difference Method

  • Li, Zhen-Zhe;Heo, Kwang-Su;Choi, Jun-Hoo;Seol, Seoung-Yun
    • Proceedings of the KSME Conference
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    • 2008.11b
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    • pp.2254-2255
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    • 2008
  • Thermoforming is one of the most versatile and economical process to produce polymer products. The drawback of thermoforming is difficult to control thickness of final products. Temperature distribution affects the thickness distribution of final products, but temperature difference between surface and center of sheet is difficult to decrease because of low thermal conductivity of ABS material. In order to decrease temperature difference between surface and center, heating profile must be expressed as exponential function form. In this study, Finite Difference Method was used to find out the coefficients of optimal heating profiles. Through investigation, the optimal results using Finite Difference Method show that temperature difference between surface and center of sheet can be remarkably minimized with satisfying Temperature of Forming Window.

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Analysis of the Parameters of Magnetocardiography Depending on the Age and Gender (남녀 및 나이에 따른 심자도 변수 차이 분석)

  • Lim, Hyun-Kyoon;Chung, Nam-Sik;Lee, Yong-Ho;Kwon, Hyuk-Chan;Joung, Bo-Young;Park, Yong-Ki
    • Journal of Biomedical Engineering Research
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    • v.28 no.4
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    • pp.530-538
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    • 2007
  • Magnetocardiography (MCG) is a device to measure the magnetic field from the heart. It is a noninvasive device and takes only few minutes to record magnetocardiogram from a subject. In this study, we compared the difference of MCG data recorded from 56 normal subjects in early twenties (28 males and 28 females, mean $age=21.0{\pm}1.6$ years) and 36 elderly subjects (20 males and 16 females, mean $age=61.9{\pm}6.9$ years) for the analysis of the age and gender difference. A total of 24 parameters used in the analysis were derived from QRS complex, R-wave, T-wave, and ST-T period. As a result, seven parameters including maximum current angle and map angle showed the significant difference (p<0.01 and p<0.05, respectively) between young males and young females. Significant difference (p<0.05) between elderly males and elderly females was found from a parameter, pole distance at T-wave peak. In the comparison of age difference, seven parameters regarding current moment, pole distance, and dynamics showed the significant difference between young and elderly males. Eight parameters also showed significant difference (p<0.05) between two younger and elderly female groups. Results showed that parameters regarding current moment, pole distance, and dynamics might be changed when people get older. In conclusion, gender and age difference should be considered when MCG data are analyzed for certain parameters.

A Study on the Education Training Satisfaction of Employees in General Hospitals (종합병원 직원의 교육훈련 만족에 관한 연구)

  • Ahn, Sang-Yoon
    • Korea Journal of Hospital Management
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    • v.17 no.2
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    • pp.34-51
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    • 2012
  • This study is an empirical research to identify difference of education training satisfaction by demographic variables, and to investigate the influence of education training satisfaction on the member's organizational commitment in general hospitals. As a result of ANOVA, t-test based on the data of 325 employees in 7 general hospitals in Korea, education training satisfaction has a significant difference by a construct and demographic variables. Education training satisfaction has a significant difference by a construct such as education training system, education training administration and education training practice. Education training satisfaction has a significant difference by occupation, career, scholarship. Education training satisfaction has a partly significant difference by status, age. But it has not a significant difference by sex distinction. Satisfaction of education training system and education training practice has a significantly positive relationship with organizational commitment. But Satisfaction of education training administration has a partly positive relationship with organizational commitment. By these results, the advanced education training structure needs to equipped in order to elevate management performance in general hospitals.

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Voice Activity Detection Based on Signal Energy and Entropy-difference in Noisy Environments (엔트로피 차와 신호의 에너지에 기반한 잡음환경에서의 음성검출)

  • Ha, Dong-Gyung;Cho, Seok-Je;Jin, Gang-Gyoo;Shin, Ok-Keun
    • Journal of Advanced Marine Engineering and Technology
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    • v.32 no.5
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    • pp.768-774
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    • 2008
  • In many areas of speech signal processing such as automatic speech recognition and packet based voice communication technique, VAD (voice activity detection) plays an important role in the performance of the overall system. In this paper, we present a new feature parameter for VAD which is the product of energy of the signal and the difference of two types of entropies. For this end, we first define a Mel filter-bank based entropy and calculate its difference from the conventional entropy in frequency domain. The difference is then multiplied by the spectral energy of the signal to yield the final feature parameter which we call PEED (product of energy and entropy difference). Through experiments. we could verify that the proposed VAD parameter is more efficient than the conventional spectral entropy based parameter in various SNRs and noisy environments.

Effect of Difference Education Quality on Student Satisfaction and Student Loyalty (차별적인 교육품질이 학생만족과 학생 충성도에 미치는 영향)

  • Kim, Gye-Soo
    • Journal of Korean Society for Quality Management
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    • v.41 no.1
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    • pp.53-68
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    • 2013
  • Purpose: The paper presents research that examine relationship difference education quality, satisfaction, loyalty in university education sector. Specifically, the effects of difference education quality on student satisfaction and loyalty in the context of education quality are examined. Methods: A model of difference education quality effect on student satisfaction and loyalty is introduced and tested in the university using student perceptions of provider. Questionnaire was developed, and data was collected and analyzed for this study with SEM(Structural Equation Modeling). Results: The results are as follows: Education capability, BNIE(Business Newspaper In Education) are significantly influenced on student satisfaction. In addition, student satisfaction is significantly influence on external customer satisfaction, professor image. Professor image is significantly influence on student loyalty. Conclusion: Upon learning of student need and want, professor can focus on development of difference education quality based on student need and want.

A Estimation of Contamination Degree by the Measurement of Phase Difference on the Outdoor Insulator (옥외절연물의 오손도 파악을 위한 위상차 측정)

  • 심규일;이원영;한상옥;박강식
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07a
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    • pp.443-446
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    • 2002
  • In this paper, a phase difference of liveline insulator was measured and analyzed to estimate the contamination degree. The probability of accident rises according to the increase of the contamination. So the estimation of contamination degree is very important in design and maintenance of outdoor insulator. There are many methods to measure the contamination degree, but those methods use the spacial sense to measure the contamination degree. So, we have no information about the contamination from the liveline insulator, but there is a measurement of phase difference to estimate the contamination degree. The phase difference is varied with the increase of ESDD, so the contamination degree could be estimated by using those characteristics. The experiment is performed to analyze the interrelationship between contamination degree and phase difference. The variable condition is relative humidity that increases from 30 to 100 % in a chamber. We use the DAS program to measure and analyze the data. From the result, the variation of phase difference is different by the contamination degree, so we can confirm the possibility of estimating the contamination degree by the phase difference.

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The perception of pre-service kindergarten teacher toward children's fundamental habit education (유아 기본생활습관 교육에 대한 예비유아교사의 인식)

  • Youn, Jin-Ju
    • Korean Journal of Human Ecology
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    • v.18 no.3
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    • pp.583-595
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    • 2009
  • The study was to see if the perceptions of pre-service kindergarten teacher toward the education of children's fundamental habit would show different characteristics based on their school type, education learning experience, and practicum experience. Subjects were 200 students majoring in early childhood education who were attending 3-year colleges and 4-year universities in Jellabuk-do and Daejeon. Preceding researches were referenced to develop questionnaire for the research method. The collected data was analyzed through t-test and Chi-square test. The followings are results: First, the interest in education showed significant difference in school type, but not significant difference in education learning experience and practicum experience. Second, the recognition in educational goal showed significant difference in practicum experience, but not significant difference in school type and education learning experience. the educational content showed significant difference in education learning experience, but not in school type and practicum experience. the recognition in educational principal showed significant difference in school type, but not significant difference in education learning experience and practicum experience. the recognition in educational method showed no significant difference in school type, education learning experience and practicum experience. Third, the recognition in educational hardship toward teaching showed significant difference in school type, education learning experience and practicum experience. The results of study would provide the righteous cognitive establishment of children's fundamental habit education and serve the appropriate guidelines being professor for our perspective kindergarten teachers. Also, they would be utilized as basic information to plan the direction of children's fundamental habit education to develop the program of children's life guidance.

Research on the Evaluation of the Differences in Financial Variablesof Chain Restaurants Using Multivariate Analysis of Variance (다변량 분산분석을 이용한 체인 레스토랑의 재무변수 차이 평가 연구)

  • Kang, Seok-Woo
    • Culinary science and hospitality research
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    • v.14 no.1
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    • pp.21-38
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    • 2008
  • This research aimed to analyze the differences in financial variables classifying chain restaurants. A total of 126 samples were drawn from financial statements for $2001{\sim}2006$. As a result of analysis, there was a significant difference in Pillai's Trace, Wilks' Lambda, Hotelling's Trace, and Roy's Largest Root values at the significant probability value(p<0.05) based on F value in terms of stability among chain restaurants. Difference was found only in current rate and liabilities in ANOVA. There was a great difference in current rate among institutional restaurants, fast food restaurants, and cafeterias. There was a significant difference in Pillai's Trace, Wilks' Lambda, Hotelling's Trace, and Roy's Largest Root values at the significant probability value(p<0.05) based on F value in terms of restaurants' profitability. In ANOVA, difference was found only in net profits to net sales. It was revealed that all factors showed no significant differences in multiple comparison. All multi-variant test statistics showed a significant difference in growth and turnover. ANOVA showed a significant difference in net sales growth rate, net profit growth rate, and total assets growth rate.

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