• Title, Summary, Keyword: variable

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VARIABLE STARS IN THE REGION OF THE OPEN CLUSTER NGC 457 (산개성단 NGC 457 영역의 변광성)

  • Jeon, Young-Beom;Park, Yoon-Ho;Lee, Sang-Min
    • Publications of The Korean Astronomical Society
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    • v.32 no.3
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    • pp.421-438
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    • 2017
  • Through the short-period variability survey program, we obtained time-series BV CCD images for $1.5^{\circ}{\times}1.0^{\circ}$ region around the young open cluster NGC 457. As a result, we have detected 61 variable stars including 31 new ones after checking light curves of all stars by eyes. The 61 variable stars were included 14 ${\delta}$ Scuti variable stars, a ${\beta}$ Cephei variable star, 10 variable Be and slowly pulsating B stars, 13 eclipsing binary stars, 21 semi-long periodic or slow irregular variables and an RR Lyrae variable star, respectively. Many variable B-type stars were known through a well-defined zero-age main sequence to the ${\beta}$ Cepheid region of NGC 457. Most of the variable B-type stars found this paper were known variable stars. But, 11 out of 14 ${\delta}$ Scuti variable stars were newly discovered. The new variable stars except for ${\delta}$ Scuti stars were 4 variable B-type stars, 5 eclipsing binaries and 11 semi-long periodic or slow irregular variables. We have performed frequency analysis for all ${\delta}$ Scuti stars, a ${\beta}$ Cepheid star and an RR Lyrae star.

A Process Control Procedure Based on the Correlated Variable (상관변수에 의한 공정관리 절차)

  • Kwon, Hyuck-Moo
    • Journal of Korean Institute of Industrial Engineers
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    • v.27 no.2
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    • pp.135-139
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    • 2001
  • A process control procedure is suggested when screening inspection is performed with a surrogate variable correlated with the performance variable. Assuming bivariate normal distribution for the performance and screening variable, the procedure is designed on the basis of the time required for detecting process shift.

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Study on 2 dimensional Control Chart and Search interrelation Independent variable and dependent variable by using control chart considered simultaneously (2차원 관리도와 관리도를 이용한 독립변수와 종속변수의 관계연구)

  • Ree, Sang-Bok;Kim, Myung-Hoon
    • Proceedings of the Korean Society for Quality Management Conference
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    • pp.195-198
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    • 2006
  • In this paper, we propose a 2dimension Control Chart. Suggested which Control chart augments Schwart Control chart which is 1-dimensional and Independent variable and dependent variable interrelationship by using control chart. Schwart control chart cannot use input variable and output variable together. In this paper, we try to analysis input variable and output variable dependent and effect. So called 2-dimensional control char.

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Effects on the Fishing Industry of Changes in Foreign Exchange Rates;-The Pass-Through of Exchange Rate Changes to Export Price- (환율변동이 수산업에 미치는 영향;-수출가격에의 전가도를 중심으로-)

  • 박영병;어윤양
    • The Journal of Fisheries Business Administration
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    • v.26 no.2
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    • pp.75-92
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    • 1995
  • This paper tried to estimate the pass - through of exchange rate changes to export price of fishery products using export price function. The results are as follows : 1) The variable of fluctuation of exchange rate of Won(equation omitted) to Yen(equation omitted)(variable E2) is more powerful explanatory variable than that of Won to U.S. dollar to explain the fluctiation of export price of fishery products(varible $P_{t}$)- 2) The variable of fish catches(variable K $P_{t}$) is also found to be a statistically significant varible but that of producer price index is not found. 3) The variable E2 have statistically a more influence on variable $P_{t}$ than variable K $P_{t.}$ 4) The estimation shows us that 1% of fluctuation of variable E2 could result in 0.9978% of fluctuation of variable $P_{t.}$

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Economic Design of Variable Sample Size ${\bar{X}}$ Control Chart Using a Surrogate Variable (대용변수를 이용한 가변형 부분군 크기 ${\bar{X}}$ 관리도의 경제적 설계)

  • Lee, Tae Hoon;Lee, Min Koo;Kwon, Hyuck Moo;Hong, Sung Hoon;Lee, Jooho
    • Journal of the Korean Society for Quality Management
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    • v.45 no.4
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    • pp.943-956
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    • 2017
  • Purpose: This paper proposes a VSS(Variable Sample Size) ${\bar{X}}$ control chart using surrogate variable and shows its effectiveness compared with FSS(Fixed Sample Size) ${\bar{X}}$ control chart using either performance variable or surrogate variable. Methods: The expected cost function of VSS ${\bar{X}}$ control chart is derived. The optimal designs are then found for numerical examples using a GA(genetic algorithm) and compared to those of the FSS ${\bar{X}}$ control charts. Results: Computational results show that VSS ${\bar{X}}$ control chart using surrogate variables is superior to FSS ${\bar{X}}$ control chart using either performance variable or surrogate variable from the economic view points. Conclusion: The proposed VSS ${\bar{X}}$ control chart will be useful in industry fields where a performance variable is not avaliable or too costly.

A Study on Selection of Split Variable in Constructing Classification Tree (의사결정나무에서 분리 변수 선택에 관한 연구)

  • 정성석;김순영;임한필
    • The Korean Journal of Applied Statistics
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    • v.17 no.2
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    • pp.347-357
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    • 2004
  • It is very important to select a split variable in constructing the classification tree. The efficiency of a classification tree algorithm can be evaluated by the variable selection bias and the variable selection power. The C4.5 has largely biased variable selection due to the influence of many distinct values in variable selection and the QUEST has low variable selection power when a continuous predictor variable doesn't deviate from normal distribution. In this thesis, we propose the SRT algorithm which overcomes the drawback of the C4.5 and the QUEST. Simulations were performed to compare the SRT with the C4.5 and the QUEST. As a result, the SRT is characterized with low biased variable selection and robust variable selection power.

A Study on the Internalizing·Externalizing Problems of Multicultural Children (다문화가정 아동의 내재화·외현화 문제에 관한 연구)

  • Woo, Hee Jung
    • Journal of the Korean Home Economics Association
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    • v.51 no.2
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    • pp.195-206
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    • 2013
  • This study was conducted in order to investigate the variables that relate and affect the internalizing and externalizing problems of multicultural children. 159 multicultural children in the $3^{rd}{\sim}6^{th}$grade were selected from elementary schools in Gwangju and the Jeollanamdo area. The data was analyzed by using the frequency, Cronbach's ${\alpha}$, t-test, ANOVA, Pearson's correlation and hierarchical regression by SPSS 12.0 program. The results were as follows: first, the internalizing problems were different according to the socio-demographic variable: (gender, subjective economic level), multicultural characteristic variable: (mother's communication ability, likability of mother's nationality, etc.), parent-child relationship variable: (relationship with mother, relationship with father) and social support variable: (peer support, teacher support). Further, the externalizing problems were different according to the socio-demographic variable: (gender), multicultural characteristic variable: (mother's nationality, mother's communication ability, etc.), parent-child relationship variable: (relationship with mother, relationship with father) and social support variable: (peer support, teacher support). Second, the influential variables regarding the internalizing problems were children's stress from cultural adaptability and the likability of the mother's nationality of the multicultural characteristic variable group, peer support of the social support variable group and the subjective economic-level of the socio-demographic variable group. Moreover, the influential variable on the externalizing problems was children's stress from the cultural adaptability of the multicultural characteristic variable group. The most influential variable of such variables was children's stress from cultural adaptability of the multicultural characteristic variable group. The results of this study will provide information for the development of educational and therapeutic intervention program for multicultural children.

A Meta-Analysis of the Variables Related with Social Support for Female Marriage Immigrants (여성결혼이민자의 사회적 지지와 관련 변인 메타분석)

  • Lee, Eun-Joo;Jun, Mi-Kyung
    • Journal of Families and Better Life
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    • v.31 no.5
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    • pp.125-141
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    • 2013
  • This research aims to integrate study results through a meta-analysis of previous studies on the variables related with social support for female marriage immigrants. Based on the results, this study established the foundation of an integrated social support system for female marriage immigrants which considers both the functional perspective and structural perspective of social support, and suggested plans for an efficient support system. All social support was positively associated with female marriage immigrants marriage life, child-rearing behavior and attitude, reduction of stress and depression and psychological stability. In relation to the effect size of each variable related with all social support, the marriage variable had the biggest relationship with it, followed by the parenting variable, the psychological variable and the stress variable in that order. With reference to the relationship with related variables according to the sub-domain of social support, from the structural perspective, spousale support showed a high relationship with the marriage variable and the stress variable. It was also especially, very highly related with the marriage variable. In addition, a married woman's family support and expert support had an intermediate relationship with the marriage variable, and the husband's family support and friend support had a low relationship with it. From the functional perspective, material support had a very high relationship with the marriage variable, whereas it had a low relationship with the stress variable and the psychological variable. Emotional support was also highly related with marriage variable, but showed an intermediate or low relationship with the psychological variable and the stress variable. On the other hand, informational support displayed an intermediate relationship with the stress variable and the psychological variable, and a high relationship with the marriage variable. Lastly, evaluative support had a high relationship with the marriage variable and the psychological variable. Based on these results, this study proposed plans for an integrated social support system as follows. First, education ought to be provided for the spouses, and support for marital adjustment should be offered. Second, there plans should be made for continuous bonding with the family of origin, and support should be given to address changes in awareness of the relationship with the husband's parents. Third, it is required to revitalize the local community and self-help groups, and provide the female marriage immigrants with opportunities to participate in social activities.

Functional Data Classification of Variable Stars

  • Park, Minjeong;Kim, Donghoh;Cho, Sinsup;Oh, Hee-Seok
    • Communications for Statistical Applications and Methods
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    • v.20 no.4
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    • pp.271-281
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    • 2013
  • This paper considers a problem of classification of variable stars based on functional data analysis. For a better understanding of galaxy structure and stellar evolution, various approaches for classification of variable stars have been studied. Several features that explain the characteristics of variable stars (such as color index, amplitude, period, and Fourier coefficients) were usually used to classify variable stars. Excluding other factors but focusing only on the curve shapes of variable stars, Deb and Singh (2009) proposed a classification procedure using multivariate principal component analysis. However, this approach is limited to accommodate some features of the light curve data that are unequally spaced in the phase domain and have some functional properties. In this paper, we propose a light curve estimation method that is suitable for functional data analysis, and provide a classification procedure for variable stars that combined the features of a light curve with existing functional data analysis methods. To evaluate its practical applicability, we apply the proposed classification procedure to the data sets of variable stars from the project STellar Astrophysics and Research on Exoplanets (STARE).