• Journal of the Korean Data and Information Science Society
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• v.24 no.4
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• pp.815-824
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• 2013

Traditional Pearson chi-squared test is not appropriate for the data collected by the complex sample design. When one uses the traditional Pearson chi-squared test to the complex sample categorical data, it may give wrong test results, and the error may occur not only due to the biased variance estimators but also due to the biased point estimators of cell proportions. In this study, the design based consistent Wald test statistics was derived for k-population homogeneity test, and the traditional Pearson chi-squared test statistics was partitioned into three parts according to the causes of error; the error due to the bias of variance estimator, the error due to the bias of cell proportion estimator, and the unseparated error due to the both bias of variance estimator and bias of cell proportion estimator. An analysis was conducted for empirical results of the relative size of each error component to the Pearson chi-squared test statistics. The second year data from the fourth Korean national health and nutrition examination survey (KNHANES, IV-2) was used for the analysis. The empirical results show that the relative size of error from the bias of variance estimator was relatively larger than the size of error from the bias of cell proportion estimator, but its degrees were different variable by variable.

• Journal of Digital Convergence
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• v.14 no.8
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• pp.497-502
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• 2016

The survey is designed to provide fundamental data for assessing effects of calligraphy therapy program. An opened questionnaire asking psychological and physical experiences (3 advantages and 3 disadvantages) was given to 150 persons practicing calligraphy. Collected data were categorized into 10 psychological advantages (435 items), 6 psychological disadvantages (129 items), 9 physical advantages (302 items), and 7 physical disadvantages (150 items). Those subjective experiences were multidisciplinarily interpreted in terms of the mental and physical health and the humanistic education. A new structured assessing tool which will be developed based on the findings from the study may contribute in activating the calligraphy therapy program.

• The Korean Journal of Applied Statistics
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• v.30 no.5
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• pp.615-632
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• 2017

Unlike randomized trial, statistical strategies for inferring the unbiased causal relationship are required in the observational studies. The matching with the propensity score is one of the most popular methods to control the confounders in order to evaluate the effect of the treatment on the outcome variable. Recently, new methods for the causal inference in latent class analysis (LCA) have been proposed to estimate the average causal effect (ACE) of the treatment on the latent discrete variable. They have focused on the application study for the real dataset to estimate the ACE in LCA. In practice, however, the true values of the ACE are not known, and it is difficult to evaluate the performance of the estimated the ACE. In this study, we propose a method to generate a synthetic data using the propensity score in the framework of LCA, where treatment and outcome variables are latent. We then propose a new method for estimating the ACE in LCA and evaluate its performance via simulation studies. Furthermore we present an empirical analysis based on data form the 'National Longitudinal Study of Adolescents Health,' where puberty as a latent treatment and substance use as a latent outcome variable.

• Journal of Korean Society of Transportation
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• v.16 no.3
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• pp.93-100
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• 1998

지난 30여년간 운전자의 속도선택의 행태에 대하여 많은 연구가 이루어졌다. 그러 나, 과거 대부분의 연구는 운전자의 개별적인 특성과 제한속도에 대한 운전자의 인지 정도 를 고려하지 않고, 다만 운전자의 속도선택과 도로 및 차량간의 상호 관련성에 중점을 두고 있다. 본 연구는 운전자, 차량 및 통행특성 등의 요인을 고려하여 운전자의 속도 선택에 대 한 행태를 분석하고자 하였다. 이를 위하여 운전자의 속도 자료와 설문자료를 조사한 수, 두 가지 자료를 범주형 자료로 구분하여 Ordered Probit Model을 적용하여 분석하였다. 분 석결과 i) 고소득의 남성운전자가 고속의 주행 행태를 보였으며, 운전경력이 많은 운전자일 수록 높은 속도를 선택하는 것으로 나타났다. ii) 차량에 관해서는 배기량이 높은 차량일수 록 고속의 속도를 나타낸 반면에 안전장치가 많은 차량의 경우에는 저속의 주행속도를 보이 는 것으로 나타났다. iii) 통행 특성 면에서는 일일통행거리가 중요 변수인 것으로 나타났다. iv) 운전자의 심리적 측면에서는 운전자가 인식하고 있는 제한 속도가 또한 중요변수로 분 석되었다.

• The Korean Journal of Applied Statistics
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• v.33 no.1
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• pp.25-46
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• 2020

This paper presents ordinal probit semiparametric regression models using Bayesian Spectral Analysis Regression (BSAR) method. Ordinal probit regression is a way of modeling ordinal responses - usually more than two categories - by connecting the probability of falling into each category explained by a combination of available covariates using a probit (an inverse function of normal cumulative distribution function) link. The Bayesian probit model facilitates posterior sampling by bringing a latent variable following normal distribution, therefore, the responses are categorized by the cut-off points according to values of latent variables. In this paper, we extend the latent variable approach to a semiparametric model for the Bayesian ordinal probit regression with nonparametric functions using a spectral representation of Gaussian processes based BSAR method. The latent variable is decomposed into a parametric component and a nonparametric component with or without a shape constraint for modeling ordinal responses and predicting outcomes more flexibly. We illustrate the proposed methods with simulation studies in comparison with existing methods and real data analysis applied to a Korean National Health and Nutrition Examination Survey (KNHANES) 2016 for investigating nonparametric relationship between smoking behavior and coffee intake.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.524-531
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• 2017

Summary The purpose of this study was to understand the tendency and the meaning of day care center teachers regarding role playing through metaphorical analysis. The data were collected from 166 day care center teachers who participated in A-city university supplement education using the sentence completion metaphorical method. The collected data were categorized and analyzed through a qualitative research method conducted by 2 early childhood education specialists. The results are as follows. First, the tendency of role playing metaphorical expression was divided into 3 categories, 8 contents and the frequency of 'sociality development' was the highest followed by 'emotional development', 'development'. Second, the meaning of role playing metaphorical expression was recognized as 'social skills', 'role experience', 'imitation', and 'understanding of society' in the 'sociality development' category; as 'imagination', 'purification function', and 'means of expression' in the 'emotional development' category; and as 'essential factor of development' in the 'development' category. Based on the research result, it was suggested that the roles of education and teachers for the value and effective operation of role playing in early childhood education institutes should be reconsidered.

• Korean Journal of Social Welfare
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• v.62 no.4
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• pp.223-248
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• 2010

This study is to explore the contents and interaction of residents voluntary network and propose the strategies to promote residents voluntary network. The grounded theory was utilized to attain our object. Total of seven social worker and 17 residents participated in the study. Data were collected through in-depth interviews and documents. The data were analyzed by using Strauss and Corbin's method. Results are the followings. In open coding 13 categories, 32 subcategories and 133 concepts were constructed. In axial coding causal conditions were qualitative ascent of needs, emergence of the right welfare consumer. Phenomenon was agitation of praxis ground and grope of exist. Contextual conditions were crisis resources, skepticism of welfare. Intervention conditions were maturation of welfare cognition and proliferation of the sense of community responsibility. Strategy were resocialization of voluntary organization and construction of field related service delivery system. Consequence were grass routing welfare strategic fitting service system. In selective coding we constructed the core category: The praxis revolution from bottom for break social welfare environment.

• Archives of design research
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• v.16 no.1
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• pp.35-44
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• 2003

In the past era, acquisition and utilization of useful information was the main origin of competition. Nowadays, unlike that era, is the era of knowledge information(management) in which we should create a new knowledge on the basis of information and apply it to the field of practice. And more acquisition of information is no more the competitive power of any person, any company and any nation because in such the era of knowledge management, anyone can access and get the information he needs, utilizing internet-based searching system. Such demands of the times of knowledge management change rapidly in each field through knowledge management system and researches about knowledge management are actively processed in various academic branches. However, in our field of design, researches about those demands(knowledge management) still remain on the level of one-dimensional searching service for general data about design. Therefore, in this study, we developed building database of researches on form, color, aesthetical elements, preference image word, satisfaction etc. about CI/BI of home electronics goods, living goods, apparels, and food goods companies, also suggesting searching system through which you can obtain useful data and information helpful for designers to process CI/BI works of new product by using that database. Especially, in case of developing specific CI/BI, various search results through help of suggested system will supply a useful design concept. And more, cross table which is the result of analysis two-dimensional categorical data about existing design factors(such as form, color, aesthetical elements, preference image word, and satisfaction) will make contribution for designers to create a new design knowledge.

• The Korean Journal of Applied Statistics
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• v.27 no.7
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• pp.1077-1095
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• 2014

Unlike randomized trial, statistical strategies for inferring the unbiased causal relationship are required in the observational studies. Recently, new methods for the causal inference in the observational studies have been proposed such as the matching with the propensity score or the inverse probability treatment weighting. They have focused on how to control the confounders and how to evaluate the effect of the treatment on the result variable. However, these conventional methods are valid only when the treatment variable is categorical and both of the treatment and the result variables are directly observable. Research on the causal inference can be challenging in part because it may not be possible to directly observe the treatment and/or the result variable. To address this difficulty, we propose a method for estimating the average causal effect when both of the treatment and the result variables are latent. The latent class analysis has been applied to calculate the propensity score for the latent treatment variable in order to estimate the causal effect on the latent result variable. In this work, we investigate the causal effect of adolescents delinquency on their substance use using data from the 'National Longitudinal Study of Adolescent Health'.

• Journal of Korea Port Economic Association
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• v.29 no.1
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• pp.143-175
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• 2013

The purpose of this paper is to show the clustering trend by using the variable group benchmarking(VGB) and categorical variable(CV) models for 38 Asian ports during 9 years(2001-2009) with 4 inputs(birth length, depth, total area, and number of crane) and 1 output(container TEU). The main empirical results of this paper are as follows. First, clustering results by using VGB show that Shanghai, Qingdao, and Ningbo ports took the core role for clustering. Second, CV analysis focusing on the container throughputs indicated that Singapore, Keelong, Dubai, and Kaosiung ports except Chinese ports are appeared as the center ports of clustering. Third, Aqaba, Dubai, Hongkong, Shanghai, Guangzhou, and Ningbo ports are recommended as the efficient ports for the target of clustering. Fourth, when the ports are classified by the regional location, Dubai, Khor Fakkan, Shanghai, Hongkong, Keelong, Ningbo, and Singapore ports are the core ports for clustering. On the whole, other ports located in Asia should be clustered to Dubai, Khor Fakkan, Shanghai, Hongkong, Ningbo, and Singapore ports. The policy implication of this paper is that Korean port policy planner should introduce the VGB model, and CV model for clustering among the international ports for enhancing the efficiency of inputs and outputs.