• The Mathematical Education
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• v.46 no.3
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• pp.315-329
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• 2007

The concepts of ratio, rate, and proportion are used in everyday life and are also applied to many disciplines such as mathematics and science. Proportional reasoning is known as one of the pivotal ideas in school mathematics because it links elementary ideas to deeper concepts of mathematics and science. However, previous research has shown that it is difficult for students to recognize the proportionality in contextualized situations. The purpose of this study is to understand how the mathematical concept in the middle school mathematics curriculum is connected with ratio, rate, and proportion and to investigate the characteristics of proportional reasoning through analyzing the concept including ratio, rate, and proportion on the middle school mathematics curriculum. This study also examines mathematical concepts (direct proportion, slope, and similarity) presented in a middle school textbook by exploring diverse interpretations among ratio, rate, and proportion and by comparing findings from literature on proportional reasoning. Our textbook analysis indicated that mechanical formal were emphasized in problems connected with ratio, rate, and proportion. Also, there were limited contextualizations of problems and tasks in the textbook so that it might not be enough to develop students' proportional reasoning.

• Journal of Family Resource Management and Policy Review
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• v.8 no.1
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• pp.29-45
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• 2004

This study compared household's investment behaviors over consumer's ages before and after the economic crisis using 1995 and 2000 National Survey of Family Income and Expenditure in korea. Household's investment behaviors were compared in terms of household's financial statements, amounts and proportions invested in various assets, and rate of return on investments. The proportion invested in securities of all households. In terms of the proportion invested, consumers under 40s increased the proportion invested in insurance while consumers over 50s increased the proportion invested in savings and trusts in 1995 than in 2000. Consumers of all ages increased the proportion invested in securities in 2000 than in 1995. Young households had higher rate of return in 1995 while old households had higher rate of return in 2000.

• Journal of Digital Convergence
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• v.14 no.12
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• pp.165-172
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• 2016

Since the advent of digital games with hardware development a key component of the game characters are changed to retard the rate at which types of users based on their favorite theory of human proportion. Many popular to gamers in the game according to the change in the retard rate in a unique image of the character. Studies on the head and body proportion are thought that up to now been insufficient. The purpose of this study is to examine a fundamental human proportion that has importance as a molding factor in the game character development, it investigated the characteristics of the game character, and classifying the retard rate of the game character, through the research method of analyzing the results, into the retard rate look for and investigate studying the effect on future game images. Five types of game characters that make up the analysis were analyzed with a unique image, and the more specialized users prefer retard rate, the figurative exaggeration to retard rate than the actual main body. Utilizing a bit exaggerated the difficulties of the character looks relatively small proportion character in the graphic wallpaper increased visibility. The proportion of a game character through the study is considered as a very important factor as the game image in the game development.

• Communications for Statistical Applications and Methods
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• v.27 no.1
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• pp.141-148
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• 2020

We consider estimating the proportion of true null hypotheses in multiple testing problems. A traditional multiple testing rate, family-wise error rate is too conservative and old to control type I error in multiple testing setups; however, false discovery rate (FDR) has received significant attention in many research areas such as GWAS data, FMRI data, and signal processing. Identify differentially expressed genes in microarray studies involves estimating the proportion of true null hypotheses in FDR procedures. However, we need to account for unknown dependence structures among genes in microarray data in order to estimate the proportion of true null hypothesis since the genuine dependence structure of microarray data is unknown. We compare various procedures in simulation data and real microarray data. We consider a hidden Markov model for simulated data with dependency. Cai procedure (2007) and a sliding linear model procedure (2011) have a relatively smaller bias and standard errors, being more proper for estimating the proportion of true null hypotheses in simulated data under various setups. Real data analysis shows that 5 estimation procedures among 9 procedures have almost similar values of the estimated proportion of true null hypotheses in microarray data.

• Journal of the Korean Data and Information Science Society
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• v.28 no.2
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• pp.443-449
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• 2017

Estimation of population proportion like the distribution rate of LED TV and the prevalence of a disease are often estimated based on survey sample data. Population proportion is generally considered as a special form of population mean. In complex sampling like stratified multistage sampling with unequal probability sampling, the denominator of mean may be random variable and it is estimated like ratio estimator. In this research, we examined the estimation of distribution rate based on stratified multistage sampling, and determined some numerical outcomes using stratified random sample data with about 25% of missing observations. In the data used for this research, the survey weight was determined by deterministic way. So, the weights are not random variable, and the population distribution rate and its variance estimator can be estimated like population mean estimation. When the weights are not random variable, if one estimates the variance of proportion estimator using ratio method, then the variances may be inflated. Therefore, in estimating variance for population proportion, we need to examine the structure of data and survey design before making any decision for estimation methods.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.205-206
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• 2017

The purpose of this paper is to examine a reasonable share of cost in the apartment remodeling projects. Therefore, the case model of remodeling apartment was made up and then the rate of return by method of floor area change rate, method of proportion, method of investment earnings rate and method of proportion reflected business contribution were estimated. Consequently, the model by the method of proportion reflected business contribution presented 20.6% of rate in all apartment units.

• Journal of Preventive Medicine and Public Health
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• v.24 no.2 s.34
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• pp.211-220
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• 1991

Finances of health insurance can be explained by factors determining benefit expense and premium collection. This study was conducted to analyze factors contributing to the financial status of rural health Insurance. Nationwide 134 health insurance associations except the six pilot project counties were analyzed and obtained the followings. 1. In univariate analysis, statistically significant variables that explain 1) outpatient benefit expenditures include public health center utilization, proportion of pregnant women. premium and collection rate of premium 2) inpatient benefit expenditures include public health center utilization, Proportion of old age, proportion of pregnant women, premium and collection rate of premium 3) profits include public health center utilization, proportion of old age, proportion of pregnant women and collection rate of premium. 2. In multiple regression analysis, statistically significant determinants in 1) outpatient benefit include premium and public health utilization 2) inpatient benefit include premium 3) profit include public health center utilization, premium and collection rate of premium.

• Journal of Korean Society for Quality Management
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• v.30 no.4
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• pp.68-77
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• 2002

EM algorithm has good convergence rate for numerical procedures which converges on very small step. In the case of proportion estimation in a mixed distribution which has very big incomplete data or of update of new data continuously, however, EM algorithm highly depends on a initial value with slow convergence ratio. There have been many studies to improve the convergence rate of EM algorithm in estimating the proportion parameter of a mixed data. Among them, dynamic EM algorithm by Hurray Jorgensen and Titterington algorithm by D. M. Titterington are proven to have better convergence rate than the standard EM algorithm, when a new data is continuously updated. In this paper we suggest dynamic EM algorithm and Titterington algorithm for the estimation of a mixed Poisson distribution and compare them in terms of convergence rate by using a simulation method.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.18 no.3
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• pp.185-188
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• 2008

Objectives: The purpose of this study is to analyze the occupational safety and health(OSH) state of precarious employee. Methods: The questionnaire of this survey is composed of 9 categories that are the workplace general information and the state of occupational injury and disease, OSH organization, OSH education and training. The subjects of this survey were the Manufacturing. The hypothesis of this study is where the proportion of precarious employee is higher, the OSH state is worse. To verify this hypothesis, we grouped the subjects into three categories by the proportion of precarious employee like as 0%(all standard employee), less than 30% and 30% or more. Using the SPSS 12.0 program to analyze the data, logistic regression analysis were implemented to find affective factors for the rate of occupational injury and disease. Results: 2,633 manufacturing workplaces were included for subjects. The proportions of precarious employee were 9.6 %. In manufacturing industry, about 70 % companies had no precarious employee. 16.8 % companies were in less than 30 % group, 13.2 % companies were in 30% or more group. For the rate of occupational injury and disease, the precarious group were 0.85(${\pm}1.8$), 1.19(${\pm}2.9$), 0.59(${\pm}1.1$). There was a trend that the higher precarious proportion groups was the higher rate of occupational injury and disease by the logistic regression analysis. It is more strong relationship than company size and OSH committee. Conclusions: We could find a significant result there was a positive relationship between the hiring proportion of precarious employee and the rate of occupational injury and disease in manufacturing industry with 50 employees and more.

• Journal of Korea Foundry Society
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• v.17 no.6
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• pp.608-614
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• 1997

The effect of mold preheating temperature on the microstructure such as grain size, eutectic silicon morphology was investigated for the Al-7wt%Si-0.3wt%Mg alloy. Microstructural variations have been characterized as a function of Sr addition and cooling rate during solidification. Microstructures were correlated with cooling rate, local solidification time and eutectic nucleation temperature, etc. In this study, Sr addition caused increase of local solidification time, undercooling and reduction of eutectic plateau temperature. In logarithmic scale, local solidification time was in inverse proportion to cooling rate. Eutectic nucleation temperature was in inverse proportion to cooling rate of logarithmic scale. Increasing the cooling rate refined dendrite arm spacing and eutectic silicon. Dendrite arm spacing was logarithmically in inverse proportion to cooling rate. Without modifier addition, eutectic silicon was modified at cooling rate of $7^{\circ}C/s$ or higher.