• 천문학회지
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• 제47권4호
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• pp.137-145
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• 2014

The astrophysical parameters of four unstudied open star cluster candidates; Ivanov 2, 7, 9, and Harvard 9; are estimated for the first time using the PPMXL database. The stellar density distributions and color-magnitude diagrams for each cluster are used to determine the geometrical structure (cluster center, limited radius, core and tidal radii, the distances from the Sun, from the Galactic center and from the Galactic plane). Also, the main photometric parameters (age, distance modulus, color excesses, membership, total mass, relaxation time, luminosity and mass functions) are estimated.

• 천문학논총
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• 제32권1호
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• pp.49-53
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• 2017

The point sources in the Bright Source Catalogue of the AKARI Far-Infrared Surveyor (FIS) were classified based on their FIR and mid-IR fluxes and colours into young stellar object (YSO) and extragalactic source types using a Quadratic Discriminant Analysis method (QDA) and Support Vector Machines (SVM). The reliability of the selection of YSO candidates is high, and the number of known YSO candidates were increased significantly, that we demonstrate in the case of the nearby open cluster IC348. Our results show that we can separate galactic and extragalactic AKARI point sources in the multidimensioal space of FIR fluxes and colours with high reliability, however, differentiating among the extragalactic sub-types needs further information.

• 천문학회지
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• 제44권1호
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• pp.33-38
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• 2011

We study near-infrared properties of the old open cluster King 11, based on the 2MASS photometric data. We determine the location of the red giant clump(RGC) in the (K, J - K) colo-magnitude diagram and derive the distance modulus of King 11 to be $(m-M)_0$ = $12.50{\pm}0.10$ using the mean K magnitude of RGC. From the red giant branch slope - [Fe/H] relation we obtain the metallicity of this cluster, [Fe/H]=$-0.17{\pm}0.07$. The age and interstellar reddening of this cluster are estimated to be log t = $9.48{\pm}0.05$, E(B-V)=$0.90{\pm}0.03$, by applying Padova isochrone fits to the data.

• 천문학회지
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• 제44권1호
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• pp.1-11
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• 2011

A sample of 145 JHK-2MASS observations of NGC open star clusters is studied, of which 132 have never been studied before. Twelve are classified as non-open clusters and 13 are re-estimated self-consistently, after applying the same methods in order to compare and calibrate our reduction procedures. The fundamental and structural parameters of the 120 new open clusters studied here are derived using color-magnitude diagrams of JHK Near-IR photometry with the fitting of solar metallicity isochrones. We provide here, for the first time, a catalog of the main parameters for these 120 open clusters, namely, diameter, distance, reddening and age.

• Nutrition Research and Practice
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• 제4권6호
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• pp.528-534
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• 2010

This study explores the influence of health behaviors and individual attributes on adolescent overweight and obesity using data from Wave II (Add Health). Structural equation model/ path analysis using maximum likelihood estimation was utilized to analyze the relationships of health behaviors and attributes with obesity. Results of the model reveal that the causal paths (adolescents' attributes and health behaviors) for overweight and obesity were different for African American and Caucasian adolescents. Generally, African Americans were more susceptible to overweight and obesity than Caucasians. Although increasing levels of vigorous physical activities lowers the risk for obesity among African American and Caucasian adolescents alike, low family SES and being sedentary were associated with overweight and obesity among Caucasians. No significant associations were found among African Americans. Increased hours of sleep at night relate positively with obesity among African Americans. These findings suggest important elements in the consideration of race in developing effective intervention and prevention approaches for curbing the obesity epidemic among U.S. adolescents.

• Asian Journal for Public Opinion Research
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• 제8권2호
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• pp.144-159
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• 2020

This paper investigated the impact of grit on sustainable behavior and emotional well-being. A questionnaire about grit, sustainable behavior, and emotional well-being was administered to 273 undergraduate students in South Korea. To examine the association between the variables, this study used two spell out (SEM) comparison models. The results show that grit is positively related to sustainable behavior and emotional well-being. The effect of grit on emotional well-being was mediated by sustainable behavior. The effect of grit is higher on sustainable behavior than emotional well-being. In addition, sustainable behavior has a positive relationship to emotional well-being. The results show that the grit has an important implication for sustainable environment education and individual well-being.

• 천문학회지
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• 제37권3호
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• pp.119-129
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• 2004

A new method has been developed to solve the star cluster membership problem. It is based on synthetic photometry employing the Black Body concept as stellar radiation simulator. Synthetic color-magnitude diagram is constructed showing the main sequence band and the positions of binary star systems of combinations of various components through different photometric tracks. The method has been applied to the Hyades. The cluster membership problem has been re-appraised for the cluster (both single and binary) stars. For the binary members, the components' spectral types have been derived by the method. The results obtained agree very well with those found in literature, The method is simpler than the others and can be developed to undertake other cases as multiple star systems.

• 천문학회지
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• 제49권2호
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• pp.53-57
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• 2016

We present an optical UBVRI photometric analysis of the poorly studied open star cluster IC 2156 using Sloan Digital Sky Survey data in order to estimate its astrophysical properties. We compare these with results from our previous studies that relied on the 2MASS JHK near-infrared photometry. The stellar density distributions and color-magnitude diagrams of the cluster are used to determine its geometrical structure, real radius, core and tidal radii, and its distance from the Sun, the Galactic plane, and the Galactic center. We also estimate, the age, color excesses, reddening-free distance modulus, membership, total mass, luminosity function, mass function, and relaxation time of the cluster.

• 한국직업건강간호학회지
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• 제24권3호
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• pp.204-213
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• 2015

Purpose: This study investigated the relationship between working conditions and smoking among Korean employees using nationally representative data. Methods: We analyzed data from the Third Korean Working Conditions Survey to identify associations between various working conditions and smoking. We calculated the smoking prevalence depending on individual characteristics and working conditions. Also, multivariate logistic regression analysis was used to investigate the relationship between working conditions and smoking. Results: Company size, occupation type, employment type, working hours, working-time flexibility, and smoking-area policy were related to smoking among male employees, while company size, occupation type, employment type, and smoking-area policy were associated with smoking prevalence among females. Conclusion: Our results indicate that working conditions influence smoking prevalence, and the implementation of smoke-free policies is needed to target specific working conditions, including a strict no-smoking-area policy.

• 대한인간공학회지
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• 제32권3호
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• pp.259-266
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• 2013

Objective: This study aims to evaluate the workloads of industrial and automobile storage battery industries and their association to biological exposure indices. Background: Occupational lead exposure at battery manufacturing workplace is the most serious problem in safety and health management. Method: We surveyed 145 workers in 3 storage battery industries. Environmental factors(lead in air, temperature, humidity and vibration)), biological exposure indices(lead in blood and zinc protoporphyrin in blood) and individual workload factors(process type, work time, task type, weight handling and restrictive clothing) were measured in each unit workplace. Results/Conclusion: Air lead concentration is statistically significant in associations with workload factors(process type, work time, task type, and restrictive clothing) and environmental factors (humidity and vibration), whereas zinc protoporphyrin in blood are significantly associated with work time and weight handling. And lead in blood is significantly associated with work time, weight handling and temperature. Application: The results of this study are expected to be a fundamental data to job design.