• The Korean Journal of Applied Statistics
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• v.24 no.6
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• pp.1129-1138
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• 2011

Small area estimation has received significant intention in recent years due to a growing demand for reliable local area statistics. Traditional area-specific direct estimates based solely on sample survey data in the areas of interest do not provide adequate small area precision; however, design-based indirect local area estimators borrow strength from sample observations of related areas to increase the effective sample size. Design-based indirect estimation methods such as synthetic and composite estimators are considered to adjust local area unemployment rate estimates in the Korean Economically Active Population Survey. This study suggests an efficient alternative to minimize the cost to construct the unemployment rate of a local area through simulation under the condition that we can maintain a certain level of CV for the estimates. We obtained the results that the composite estimators using a sample size greater than 10 are more stable and significant at the level of CV 25% in our design scheme.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.111-116
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• 2001

Waste office paper, photocopied or laser printed, has recently increased along with office automatization. In waste office paper, toner ink is used as the printing medium in place of conventional oil ink. Since toner ink cannot be saponificated by alkali and be decolored by bleaching, different from the case of oil ink, toner remains on regenerated paper as black specks. Although cascade recycling of waste office paper is compelled at present, the demand for low-grade paper is limited. From such circumstances, a new separation process for waste office paper is demanded to achieve parallel recycling. At the first stage of separation studies, the sharpness of separation is evaluated using small separators to obtain fundamental data. In a lab-scale separator, the sample amount of one feed is generally a few grams. However, the sample amount used for brightness, ERIC, and image analysis that are generally used to evaluate the efficiency of deinking are not small for lab-scale tests of these analyses. This paper describes an investigation of a sheet preparation method by a small amount of sample under 0.5g and compares the precision of toner content determination of spectroscopic analysis and image analysis from the viewpoint of separation evaluation. The easiness and convenience of the operation using only general-purpose equipments has also been set as a principle purpose. From the viewpoint of an analysis that yields high precision with a small amount of sample in short time, the method calculating the absorption coefficient from diffuse reflectance in the visible region is the most rational method in this study.

• Korean Journal of Occupational Health Nursing
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• v.10 no.1
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• pp.55-65
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• 2001

The purpose of this study was to find out the status of occupational health management and the degree of recognition about the occupational health management of employees 248 small-scale enterprises which have been managed by the small-scale enterprises health care management support institution in 1999, were selected for study, in Kwang-Ju City. 98 employees were selected in 116 industries of them to grasp recognition of employees about the occupational health management. ► The Status of Occupational Health Management 1. Of the sample industries, 62.1 percent employed eleven to twenty-nine workers. Of the sample workers, 72.1 percent occupied workers who were engaged in the production line. 2. Environment evaluation was made on 82.7 percent of the sample industries and general exam made on 66.5 percent and specific health exam done on 73.4 percent. 3. The harmful factors in the sample industries were found to lie noise, dust, solvent, heavy metal, etc. 4. In general health exam 1,774 workers were participated and 148 workers got the result of above grade C and were diagnosed as having the problems with digestive system (63.6%), circulatory system(20.6%). etc. ► The Degree of Recognition about The Occupational Health Management of Employees. 1. Respondents were mainly in the twenties (42.9%), males(69.1%), duration of working period of five to ten years(24.0%), office workers(51.0%), monthly income under one million(55.7%). 2. Recognition of employees about the occupational health management consists of workplace environmental evaluation, health education, health exam and protector management. Their recognition on health education showed high score (mean 3.1), but generally the score was low(mean 2.9).

• Journal of the Korean Data and Information Science Society
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• v.28 no.5
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• pp.1153-1165
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• 2017

Structural equation modeling (SEM) is a basic tool for testing theories in a variety of disciplines. A maximum likelihood (ML) method for parameter estimation is by far the most widely used in SEM. Alternatively, two-stage least squares (2SLS) estimator has been proposed as a more robust procedure to address model misspecification. A regularized extension of 2SLS, two-stage ridge least squares (2SRLS) has recently been introduced as an alternative to ML to effectively handle the small-sample-size issue. However, it is unclear whether and when misspecification and small sample sizes may pose problems in theory testing with 2SLS, 2SRLS, and ML. The purpose of this article is to evaluate the three estimation methods in terms of inferences errors as well as parameter recovery under two experimental conditions. We find that: 1) when the model is misspecified, 2SRLS tends to recover parameters better than the other two estimation methods; 2) Regardless of specification errors, 2SRLS produces small or relatively acceptable Type II error rates for the small sample sizes.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.171-174
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• 2009

Purpose: Cancerous death rate 1 place from 2008 year domestic is the lung cancer. The body count which is caused by in the lung cancer every year is increasing. At this lung cancer is the most non small cell lung cancer. $Monototal^{TM}$ test is short reaction time. it is known as the experiment where the example standard of living is high about non small cell lung cancer. This is the study evaluate usefulness of $Monototal^{TM}$ kit. Materials and Methods: $Monototal^{TM}$ were measured using IRMA kit, using 40 CEA positive patients sample which are diagnosed NSCLC, 15 SCC positive patients sample which are diagnosed NSCLC, 40 Cyfra 21-1 positive sample, 20 negative sample in Seoul national university from March to April, 2009. Results: According to result of the $Monototal^{TM}$ test, which is benignancy rate 87.5% in CEA positive patients sample, 93.3% SCC positive patients sample and 100% Cyfra 21-1 positive sample Conclusions: We recommend that using of $Monototal^{TM}$ parallel with different tumor markers. It was useful that diagnosis and convalescence presumption of Non small cell lung cancer.

• Korean Journal of Agricultural Science
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• v.37 no.3
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• pp.457-464
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• 2010

The low melting alloy impregnated wood composites with natural grain of thinned Juglans mandshurica was made and evaluated in this study. And the proper manufacturing conditions was also investigated in this study. The low melting alloy with bismuth(Bi) and tin(Sn) which are harmless to humans, was applied for this novel composites, which showed not only no defects of discoloration, delamination, swelling, and cracking, because of high dimensional stability and low thickness swelling, but also much improved performance such as high bending strength, high hardness, low abrasion, high thermal conductivity as floor materials. This study also suggested the proper impregnating condition, such as 10 minutes of the preliminary vacuum time, $187^{\circ}C$ of the heating temperature and 10 minutes of the maintaining pressure time at the pressure of 30kgf/$cm^2$. The produced composites showed 9 times higher density for small specimen, 6.6 times for actual size sample and great increase in bending strength from 102.05N/$mm^2$ to 189.47N/$mm^2$ for small size sample and to 205.4N/$mm^2$ for actual size sample, also great increase in hardness from 15.1N/$mm^2$ to 73.38N/$mm^2$ for small size sample and 64.87N/$mm^2$ for actual size sample. And the composites demonstrated great decrease in abrasion depth and in water absorption.

• Journal of Korean Society of Forest Science
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• v.3 no.1
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• pp.18-22
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• 1963

1. Objects The experiments of catalytic aharcoaling were carried out for the fallowing purposes. (1) To determine the economically desirable amount of catalytic materials to be used when a catalytic charcoaling is practiced. (2) To observe the rate of carbonization of non-treated charcoal wood when the catalytic charcoaling is proceeded in the same charcoal pit. 2. Meterials (1) Small sample chips made of oak (Q. accutissima Carr.), measured by 0.5cm in width and thickness, respectively, and 1cm in length, were used as charcoal wood in each experiment. (2) Ammonium chloride was used as a catalytic material and electric kiln as a charcoaling apparatus. 3. Experiment (1) The sample chips were put into a electric oven for three hours at the temperature $60^{\circ}{\sim}70^{\circ}C$ in order to reduce some water contents. (2) Oven dried sample chips were then soaked for an hour in solution of ammonium chloride. Three kinds of solution were prepared, that is, 2.5%, 5%, and 10%, solution in which the amount of ammonium chloride used was weighed at the rate of 0.5%, 1.0%, and 2.0% to the total weight of the sample chips, resppectivelly. (3) Soaked sample chips were put in the air for 12 hours to reduce some water contents, and then were put into electric oven for 2 hours at the temperature $105^{\circ}{\sim}110^{\circ}C$. (4) Dried sample chips were kept in a desiccator with control sample chips which were treated excarly the same process as the treated sample chips except only not using the ammonium chloride in the process of soking. (5) Sample chips kept in the desiccator were used at random in each charcoaling experiment. (6) Charcoaling in the electric kiln were carried out by using small crucibles with complete cover to reduce the amount of ash. At each charcoaling experiment four crucibles filled with sample ships, weighed about 20gr, were put into electric kiln. The charcoaling was continued for an hour at the temperature $400^{\circ}{\sim}450^{\circ}C$. (7) In order to investigate the influence given by the gases produced during the catalytic charcoaling to the rate of carbonization of non-treated sample chips, the following experiment was done. (a) A crueible was divided into two parts by inserting a fine iron net at the middle of the crucible, and then non-treated sample chips, weighed about 10gr, were put in the upper part of the crucible and treated sample chips, weighed also about 10gr, were put in the under part. (b) The crucibles filled with two kinds of sample chips were put into a electric kiln for an hour at the temperature $400^{\circ}{\sim}450^{\circ}C$. 4. Results. Results for two replications (with four crucibles in one replication) for each experiment designed are as follows : (1) The rats of carbonization of the non treated sample chips, and that of the treated sample chips with ammonium chloride at the rate of 1.5%, 1.0%, and 2.0% to the total weight of the sample chips used were averaged at 19.85%, 22.63%, 24.14%, and 26.60%, respectively. (2) The rats of carbonization of the non-treated sample chips were averaged at (a) 20.04% (0.5% treatment), (b) 20.28% (1.0% treatment), and (c) 20.61% (2.0% treatment) when the treated sample chips were carbonized in the same crucible.

• The Korean Journal of Applied Statistics
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• v.10 no.2
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• pp.339-352
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• 1997

Chi-square test based on large sample theory is inappropriate for testing the row homogeneity in two-way contingency table with several sparse cells. For that case, exact testing methods has been developed in the literature and implemented in StatXact(1991). However, considerable computing time is inevitable for moderate size tables. So, Monte Carlo approximation is recommended frequently. In this study, we propose a simple algorithm for generating two-way random tables with fixed row and column margins for small sample chi-square test. Also, we develop “Turkey-type” method for multiple between-row comparisons.

• Journal of Korean Society for Quality Management
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• v.22 no.2
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• pp.89-97
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• 1994

We consider the linear calibration model: $y_1={\alpha}+{\beta}x_i+{\sigma}{\varepsilon}_i$, i = 1, ${\cdots}$, n, $y={\alpha}+{\beta}x+{\sigma}{\varepsilon}$ where ($y_1$, ${\cdots}$, $y_n$, y) stands for an observation vector, {$x_i$} fixed design vector, (${\alpha}$, ${\beta}$) vector of regression parameters, x unknown true value of interest and {${\varepsilon}_i$}, ${\varepsilon}$ are mutually uncorrelated measurement errors with zero mean and unit variance but otherwise unknown distributions. On the basis of simple small-sample low-noise approximation, we introduce a new method of comparing the mean squared errors of the various competing estimators of the true value x for finite sample size n. Then we show that a class of estimators including the classical and the inverse estimators are consistent and first-order efficient within the class of all regular consistent estimators irrespective of type of measurement errors.

• Journal of the Korean Data and Information Science Society
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• v.11 no.1
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• pp.111-126
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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 than direct estimator.