• Bulletin of the Korean Mathematical Society
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• v.58 no.2
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• pp.419-431
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• 2021

In this paper we discuss the classical problem of finding conditions on the entire coefficients A(z) and B(z) guaranteeing that all nontrivial solutions of f" + A(z)f' + B(z)f = 0 are of infinite order. We assume A(z) is an entire function of completely regular growth and B(z) satisfies three different conditions, then we obtain three results respectively. The three conditions are (1) B(z) has a dynamical property with a multiply connected Fatou component, (2) B(z) satisfies T(r, B) ~ log M(r, B) outside a set of finite logarithmic measure, (3) B(z) is extremal for Denjoy's conjecture.

• Journal of health informatics and statistics
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• v.43 no.4
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• pp.300-306
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• 2018

Objectives: The purpose of this study is to demonstrate empirically through a specialist AHP analysis what factors should be more important in the development of the public health care system. In addition, we will use Analytic Hierarchy Process (AHP) method for experts to achieve research purpose. Methods: The data analysis method of this study is as follows. First, we set up three metrics in order to measure the relative importance between the factors to be improved for the development of the public health care system and each of the sub-factors. A total of nine measurements (items) were set by combining the three measurement criteria for each measurement index. Second, the relative importance and priority analysis use the AHP analysis. Third, the subjects of this study were 15 experts in the field of public health care. The statistical processing was performed using the Expert Choice 2000 statistical program. Results: In order to development of the public health care system, experts ranked the most important as improvement in the systematic aspect of public health care (56%) as the first priority. Next, the relative importance analysis of the measurement items considering the multiple-weights of the sub-factors is as follows. The strengthen institutional improvement (revitalization of secondary public function hospital) was the number one, strengthen cooperation between agencies was the second, and Re-establishing the role of local public health care system was the third place. Conclusions: Considering the relative importance, factors that are considered to be important in the first place may not be improved as the best policy alternative due to limitations in spatial, temporal, financial, and institutional aspects. In this case, we suggest that we should choose the best policy alternative by using prioritization considering relative weights.

• Journal of Korea Water Resources Association
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• v.33 no.6
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• pp.783-791
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• 2000

A multidimensional representation for precipitation, given In the theory proposed by E. Waymire et al. (1984), is used for simulating rainfall in space and time. The model produces moving storms with realistic meso-scale meteorological features in time and space. The first- and second-order statistics derived from observed JX)int gauge data were used to estimate the model parameters based on the Nelder-Mead algorithm of optimization. Then twelve-year traces of rainfall intensities at fixed gage stations were generated at intervals of 1 hours. First- and second-order statistics are evaluated from the above series, which are used for estimating the parameters of one dimensional model of temporal rainfall at a point. As a result from the comparisons of one dimensional model parameters used observed and generated data from multidimensional model, we found that the multidimensional rainfall model generated visually realistic spatial patterns of rainfall as well as realistic temporal hyetographs of rainfall at a point. point.

• Journal of Korea Water Resources Association
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• v.31 no.6
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• pp.795-806
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• 1998

Soil moisture is affected by regional climate, soil characteristics and land surface condition, etc,. Especially, the changes in land surface condition is more than other factors, which is mainly due to rapid urbanization and industrialization. This study is to evaluate how the change of land surface condition impacts on soil moisture field evolution using a simple model of soil moisture dynamics. For the quantification of soil moisture field, the first half of the paper is spared for the statistical characterization based on the first- and second-order statistics of Washita '92 and Monsoon '90 data. The second half is for evaluating the impact of land cover changes through simulation study using a model for soil moisture dynamics. The model parameters, the loss rate and the diffusion coefficient, have been estimated using the observed data statistics, where the changes of surface conditions are considered into the model by applying various parameter sets with different second-order statistics. This study is concentrated on evaluating the impact due to the changes of land surface condition variability. It is because we could easily quantify the impact of the changes of its areal mean based on the linear reservoir concept. As a result of the study, we found; (1)as the variability of land surface condition, increases, the soil moisture field dries up more easily, (2)as the variabilit y of the soil moisture field is the highest at the beginning of rainfall and decreases as time goes on to show the variability of land surface condition, (3)the diffusion effect due to surface runoff or water flow through the top soil layer is limited to a period of surface runoff and its overall impact is small compared to that of the loss rate field.

• Korean Journal of Child Studies
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• v.29 no.3
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• pp.127-156
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• 2008

This study aimed to verify the mediating effects of cognitive function and social support and to establish a structural relationship between child maltreatment and resilience in school-age children (n=357) taken in by child protection service. In the first model (linear arrangement), each protective factor mediates independently between maltreatment and resilience; in the second model (arrangement in due order), cognitive function has mediating effects prior to social support. Analysis of data included descriptive statistics, Cronbach's a, confirmatory factor analysis, and structural equation modeling. Results of the first model showed indirect effects of cognitive function and social support. Results of the second model significantly affirmed that the mediators, cognitive function and social support, diminish negative effects of maltreatment by bolstering resilience.

• Journal of Korean Society for Quality Management
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• v.8 no.1
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• pp.3-7
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• 1980

In many industrial processes, there are more than two responses (i.e., yield, percent impurity, etc.) of interest, and it is desirable to determine the optimal levels of the factors (i.e., temperature, pressure, etc.) that influence the responses. Suppose the response relationships are assumed to be approximated by second-order polynomial regression models. The problems considered in this paper is, first, to propose how to select polynomial terms to fit the multivariate regression surfaces for a given set of data, and, second, to propose how to analyze the data to obtain an optimal operating condition for the factors. The proposed techniques were applied for empirical process optimization in a tire company in Korea. This case is presented as an illustration.

• Communications for Statistical Applications and Methods
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• v.31 no.4
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• pp.427-440
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• 2024

The problem addressed is that of sequentially estimating the difference between the means of two populations with respect to the squared error loss, where each population distribution is a member of the one-parameter exponential family. A Bayesian approach is adopted in which the population means are estimated by the posterior means at each stage of the sampling process and the prior distributions are not specified but have twice continuously differentiable density functions. The main result determines an asymptotic second-order lower bound, as t → ∞, for the Bayes risk of a sequential procedure that takes M observations from the first population and t - M from the second population, where M is determined according to a sequential design, and t denotes the total number of observations sampled from both populations.

• Journal of Korean Clinical Nursing Research
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• v.17 no.2
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• pp.138-149
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• 2011

Purpose: The objective of this research was to explore levels of patient safety and safe nursing activities depending on the level of nurse staffing, in order to provide effective management of nurse personnel. Methods: The research was conducted with 455 nurses from eight hospitals in B city. Data were collected according to the level of nurse personnel from second (nurse vs. patient ratio of 2.0-2.5) to fifth (ratio of 3.5-4.0) rank. The survey tools were, 'Questionnaire on Patient Safety, a Hospital Survey on Patient Safety Culture developed by AHRQ (2007), and 'Questionnaire on Patient Safety Nursing Act, in which the questions were selected from nursing-related items (Medication 6 & Safety Nursing Assurance Act 4) in the Safety Evaluation developed by Evaluation Institute of Medical Institution. Data were analyzed with SPSS PC 12.0 program using descriptive statistics, $x^2$ test, ANCOVA and $Scheff{\grave{e}}$. Results: The nurses' overall cognition level on patient safety and safe nursing activities showed that nurses who are in the second and third rank had higher scores than those in lower ranks. Conclusion: The results of this study indicate that hospitals need a higher ratio level for nurse personnel in order to assure patient safety and safe nursing activities.

• The Korean Journal of Applied Statistics
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• v.32 no.5
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• pp.721-740
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• 2019

Noise reduction is an important field in image processing and requires a statistical approach. However, it is difficult to assume a specific distribution of noise, and a spatial filter that reflects regional characteristics is a small sample and cannot be accessed in a parametric manner. The first order image differential and the second order image differential show a clear difference according to the noise level included in the image and can be more clearly understood using the canyon edge detector. The Fligner-Killeen test was performed and the bootstrap method was used to statistically check the noise level. The estimated noise level was set between 0 and 1 using the cumulative distribution function of the beta distribution. In this paper, we propose a nonparametric noise reduction algorithm that accounts for the noise level included in the image.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2004.05a
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• pp.113-117
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• 2004

We need the contingency cost in order to deal with the uncertainty to be accompanied inevitably at the construction and an every kind risk not to forecast in advance. And also the contingency colt needed for the change order and we need it for reduction of the delay and reduce the trouble between owner and constructor. This study, through checking and analyzing the risk factor, in the step of domestic construction, suggests optimal management reserve to specific business about the contract type and the scale. The main results of this research are summarized as follow. First, I investigated the recognition about the contingency cost, grasped the risk to be happened at the construction step and found out the frequency occurrence, through making up question to engineer are carrying out their job in the domestic construction. Second, I computed optimal contingency cost rate by the statistics investigation, and proposed an improvement plan and problem when compute a contingency cost.