• The Korean Journal of Applied Statistics
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• v.20 no.2
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• pp.229-244
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• 2007

Among the small area estimation methods, it has been known that hierarchical Bayesian(HB) approach is the most reasonable and effective method. However any model based approaches need good explanatory variables and finding them is the key role in the model based approach. As the lacking of explanatory variables, adopting the spatial terms in the model was introduced. Here in this paper, we evaluate the model based methods with/without spatial terms using the diagnostic methods which were introduced by Brown et al. (2001). And Economic Active Population Survey(2005) is used for data analysis.

• Journal of the Korean Data and Information Science Society
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• v.20 no.1
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• pp.77-87
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• 2009

Bayesian methods have been focused in recent years for solving small area estimation problems. In this paper, the hierarchical Bayes procedure is implemented via MCMC techniques and compared with the results of One-way, GLM-Normal, and GLM-Gamma cases by analyzing real data of insurance benefit for customer segmentations. After analyzing insurance benefit real data for customer segmentations, we can conclude that the insurance benefit estimator through the small area estimation is more efficient than the estimators by other methods. In addition, we found that the small area estimation gave accurate estimation result for the small number domains.

• Journal of Labour Economics
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• v.41 no.3
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• pp.61-93
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• 2018

This paper examines the gender pay gap among doctorate holders in Korea to understand the determinants of this gap and control of its variation. A particular focus of this study is to seek to infer the extent to which this pay gap is the consequence of gender-based disparate treatment. The main results indicate that there is a sizeable gender pay gap even among workers with doctorate degrees, that is, very highly educated workers. Moreover, this gender pay gap cannot be largely explained by gender differences in characteristics, indicating the existence of discrimination against female doctorate holders in the Korean labor market.

• The Korean Journal of Applied Statistics
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• v.18 no.3
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• pp.627-637
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• 2005

Small area estimation has been studied using various methods such as direct, indirect, synthetic and based on regression or time series model . In this paper we investigate a motel-based small area estimation which takes into account the spare time autoregressive model. The Economic Active Population Surveys in 2001 are used for analysis and the results from space-time autoregressive(STAR) and simultaneous autoregressive(SAR) model are compared with using MSE, MAE and MB.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.6
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• pp.217-221
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• 2005

The evaporation amounts of volatile Cd, Pb and Zn were characterized by measuring their total concentrations in the EAF dust-clay bodies with various mixing ratio and heat treatment temperature. TCLP test was conducted for evaluating the chemical stabilities of the heavy metal elements. Evaporation amounts and leaching concentrations of heavy metal components were strongly dependent on the mixing ratio and heat treatment temperature. The evaporation of the heavy metal components in EAF dust was effectively suppressed by increasing the clay content. The leaching concentrations of heavy metal components were decreased with increasing clay content and temperature. 20 wt% EAF dust-80 wt% clay sample shows nearly zero evaporation and leaching concentrations of heavy metal components. XRD analysis showed that peak intensities of major crystalline phases such as franklinite and quartz were decreased with increasing the heat treatment temperature which means that the stabilization mechanism of the heavy metals was related with the vitrification process of the $SiO_2$ in the clay.

• The Korean Journal of Applied Statistics
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• v.19 no.3
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• pp.421-430
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• 2006

In sample survey sample designs are performed by geographically-based domain such as countries, states and metropolitan areas. However mostly statistics of interests are smaller domain than sample designed domain. Then sample sizes are typically small or even zero within the domain of interest. Shin and Lee(2003) mentioned Spatial Autoregressive(SAR) model in small area estimation model-based method and show the effectiveness by MSE. In this study, Bayesian Auto-Poisson Model is applied in model-based small area estimation method and compare the results with SAR model using MSE ME and bias check diagnosis using regression line. In this paper Survey of Disability, Aging and Cares(SDAC) data are used for simulation studies.

• Journal of KIISE
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• v.44 no.4
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• pp.374-382
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• 2017

As the walking exercise is emphasized in personalized healthcare, numerous services demand walking information. Along with the propagation of smartphones nowadays, many step-counter applications have been released. But these applications are error-prone to abnormal movements such as simple shaking or vibrations; also, different step counts are shown when the phone is positioned in different locations of the body. In this paper, the proposed method accurately counts the steps regardless of the smartphone position by using an accelerometer and a proximity sensor. A threshold is set on each of the six positions to minimize the error of undetection and over-detection, and the cut-off section is set to eliminate any noise. The test results show that the six position type were successfully identified, and through a comparison experiment with the existing application, the proposed technique was verified as superior in terms of accuracy.

• Proceedings of the Korean Association for Survey Research Conference
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• 2000.06a
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• pp.57-73
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• 2000

Small area estimation is becoming important in survey sampling due to a growing demand for reliable small area statistics. In estimating means, totals, and other parameters for small areas of a finite population, samplie sizes for small areas are typically small because the overall sample size is usually determined to provide specific accuracy at a much higher level of aggregation than that of small area. The usual direct estimators that use the only information which is gotten from the sample in a given small area provide unreliable estimates. However, indirect estimators utilize the information from the areas related with a given small area, that is borrow strength from other related areas, and so give more accurate estimates than direct estimators. In this paper we investigate small area estimation methods such as synthetic, composite and empirical best linear unbiased prediction estimator, and apply them to real domestic data which is from the Survey of Hotels and Restaurants in In-Chon as of 1996 and then evaluate the performance of these methods by measuring average squared errors. This evaluation shows that indirect estimators, which are small area estimation methods, are more efficient direct estimator.

• Journal of the Korean Data and Information Science Society
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• v.28 no.2
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• pp.327-337
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• 2017

In this study we compared three models for small area estimation, Fay-Herriot, Hierarchical Bayses model and spatio-temporal model about charter, monthly rent price index. Charter, monthly rent price of Korea are important issue in these days. Because housing type rapidly changes from self to charter and monthly rent. The accuracy of the estimation was checked on four scales, that is ARB, ASRB, AAB, ASD. In this result, the spatio-temporal model among applied models has most optimal scales about small area estimation of charter and monthly rent index.

• Journal of the Korean Ceramic Society
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• v.33 no.7
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• pp.725-734
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• 1996

Shrinkage behaviors associated with forming drying and firing processes could be a driving force for the densification in materials. Low shrinkage-densification behaviors in clay materials have been shown to be highly dependent upon the processing parameters including particle size effect and kinetic behaviors caused by phases transformation characteristics. Chamottes pre-treated at 90$0^{\circ}C$ and 120$0^{\circ}C$ had dominent influence upon shrinkage control of materials during heat-treatment. But Coarse chamotte particles heat-treated at 120$0^{\circ}C$ did not contri-bute to any densification behaviors in clay materials while these added coarse particles could enhance near-net-shape control. Microstructure / property relationships in clay materials have been thought to be directly influenced by optimized characteristics between low shrinkage and densification behaviors.