• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 2006년도 춘계학술대회
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• pp.330-333
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• 2006

Many practical problems of quality control in service management are derived from the use of ordinal variables. Ordered linguistic variables differ from measurement variables. This paper presents a new control chart of a production process based on ordinal variables.

• 응용통계연구
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• 제19권1호
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• pp.149-161
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• 2006

CART로 대표되는 의사결정나무의 알고리즘에서 가장 중요한 요소는 분리변수의 선택방법이다. 대부분의 알고리즘은 변수의 형태가 연속형인지, 혹은 명목형(nominal)인지에 따라 별개의 변수선택방법을 적용한다. 하지만 변수의 형태가 순서형(ordinal)인 경우에는 그 변수를 연속형으로 취급하여 연속형 변수선택방법을 적용하는 것이 대부분이다. 이것은 CART와 같은 Greedy탐색을 이용하는 방법에는 문제점이 발생하지 않는다. 하지만 Greedy탐색의 약점을 보완하기 위해 통계이론을 이용하여 개발된 최근의 방법들에는 최선의 대처방법이 아니다. 따라서 본 연구에서는 의사결정 나무에서 분리변수를 선택하는데 있어서 비모수적 접근 방법인 Clamor-von Mises 검정을 이용한 방법을 순서형 변수에 사용하는 것을 제안하고, CART, C4.5, QUEST, CRUISE등 기존 알고리즘과 본 연구에서 제안하는 방법의 순서형 변수 선택력을 비교하였다. 모의실험의 결과, Clamor-von Mises 검정을 이용한 변수선택방법은 순서형 변수의 분류력을 기존 방법들에 비해 더 정확히 예측하는 좋은 성과를 보여주었다.

• Communications for Statistical Applications and Methods
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• 제16권4호
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• pp.697-705
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• 2009

The Pearson chi-squared statistic or the deviance statistic is widely used in assessing the goodness-of-fit of the generalized linear models. But these statistics are not proper in the situation of continuous explanatory variables which results in the sparseness of cell frequencies. We propose a goodness-of-fit test statistic for the cumulative logit models with ordinal responses. We consider the grouping of a dataset based on the ordinal scores obtained by fitting the assumed model. We propose the Pearson chi-squared type test statistic, which is obtained from the cross-classified table formed by the subgroups of ordinal scores and the response categories. Because the limiting distribution of the chi-squared type statistic is intractable we suggest the parametric bootstrap testing procedure to approximate the distribution of the proposed test statistic.

• 응용통계연구
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• 제23권6호
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• pp.1057-1065
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• 2010

In this paper we discuss some cautionary notes in using the Pearson chi-squared test statistic for the goodness-of-fit of the ordinal response model. If a model includes continuous type explanatory variables, the resulting table from the t of a model is not a regular one in the sense that the cell boundaries are not fixed but randomly determined by some other criteria. The chi-squared statistic from this kind of table does not have a limiting chi-square distribution in general and we need to be very cautious of the use of a chi-squared type goodness-of-t test. We also study the limiting distribution of the chi-squared type statistic for testing the goodness-of-t of cumulative logit models with ordinal responses. The regularity conditions necessary to the limiting distribution will be reformulated in the framework of the cumulative logit model by modifying those of Moore and Spruill (1975). Due to the complex limiting distribution, a parametric bootstrap testing procedure is a good alternative and we explained the suggested method through a practical example of an ordinal response dataset.

• 품질경영학회지
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• 제32권3호
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• pp.109-125
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• 2004

This paper deals with an optimal process control problem in production of hull structural steel plate with high defective rate. The main quality characteristic(dependent variable) is the internal quality(defect) of plates and is dependent on process parameters(independent variables). The dependent variable(quality characteristics) has three categorical ordinal data and there are 35 independent variables(29 continuous variables and 6 categorical variables). In this paper, we determine the main factors and to develop the mathematical model between internal quality predicted probabilities and the main factors. Secondly, we find out the optimal process condition of main factors through analysis of variance(ANOVA) using simulation. We consider three models to obtain the main factors and the optimal process condition: linear, quadratic, error models.

• 응용통계연구
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• 제15권2호
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• pp.297-310
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• 2002

Liang과 Zeger는 이산형 혹은 연속형 반복측정자료를 분석하기 위한 일반화 추정방정식 (GEE)을 제안하였다 GEE모형은 범주형 반복측정자료의 모형으로 확장될 수 있으며, 이 GEE추정량은 대표본인 경우 다변량 정규분포를 따른다. 그러나 GEE는 대표본근사이론에 기초한다. 본 논문에서는 소표본인 경우 반복 측정된 순서자료에 대한 GEE추정량의 성질을 연구한다. 우리는 두가지 방법을 사용하여 두그룹의 반복 측정된 순서자료를 생성하며 모의실험을 통하여 소표본인 경우 여러 개 범주를 갖는 순서반응 자료에 대하여 GEE추정량의 1종 오류율, 검정력, 상대효율, 두 그룹의 표본크기가 다를 경우 효과, 그리고 분산 추정량의 성질등을 연구한다.

• 운동영양학회지
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• 제25권1호
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• pp.30-34
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• 2021

[Purpose] Many studies have observed a high prevalence of erectile dysfunction among individuals performing physical activity in less leisure-time. However, this relationship in patients with type 2 diabetic patients is not well studied. In exposure outcome studies with ordinal outcome variables, investigators often try to make the outcome variable dichotomous and lose information by collapsing categories. Several statistical models have been developed to make full use of all information in ordinal response data, but they have not been widely used in public health research. In this paper, we discuss the application of two statistical models to determine the association of physical inactivity with erectile dysfunction among patients with type 2 diabetes. [Methods] A total of 204 married men aged 20-60 years with a diagnosis of type 2 diabetes at the outpatient unit of the Department of Endocrinology at PSG hospitals during the months of May and June 2019 were studied. We examined the association between physical inactivity and erectile dysfunction using proportional odds ordinal logistic regression models and continuation ratio models. [Results] The proportional odds model revealed that patients with diabetes who perform leisure time physical activity for over 40 minutes per day have reduced odds of erectile dysfunction (odds ratio=0.38) across the severity categories of erectile dysfunction after adjusting for age and duration of diabetes. [Conclusion] The present study suggests that physical inactivity has a negative impact on erectile function. We observed that the simple logistic regression model had only 75% efficiency compared to the proportional odds model used here; hence, more valid estimates were obtained here.

• 유통과학연구
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• 제20권10호
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• pp.11-17
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• 2022

Purpose: This research aims to find the link between public service Distribution and individual job performance in the provincial municipality. Research design, data, and methodology: This is a quantitative approach study with a non-experimental and correlational design. The sample consisted of 140 employees appointed and hired by the provincial municipality of Huaraz. For data collection, Two questionnaires with an ordinal Likert-type scale and the Rho Spearman correlation coefficient were used to assess the link between the research variables., For Analysis: two questionnaires with an ordinal Likert-type scale and the Rho Spearman correlation coefficient were used to determine the connection between the research variables. Results: It was determined that both variables have a high degree of correlation (0.725), indicating a direct and significant relationship between the Distribution of public service and skill performance in the provincial municipality (0.614). Conclusion: Finally, this allows us to conclude that the institutional context is essential; that is, there is a significant correlation between the PSM and contextual performance in the provincial municipality of Huaraz, which has a Rho Spearman value of 0.723.

• 응용통계연구
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• 제33권1호
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• pp.25-46
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• 2020

본 논문에서는 Bayesian spectral analysis regression (BSAR) 방법론을 이용한 베이지안 순서형 프로빗 준모수 회귀모형에 대해서 고찰한다. 순서형 프로빗 회귀모형은 순서가 있는 범주형 자료를 모형화하는 방법으로, 정규 분포의 분포함수의 역함수인 프로빗 연결함수를 이용해 각 범주의 확률과 설명변수을 연결함으로써 반응변수의 확률을 모형화한다. 베이지안 프로빗 회귀 모형은 정규 분포를 따르는 잠재변수를 도입함으로써 사후 분포 도출을 용이하게 하고, 절단점에 따라 나뉘어지는 잠재변수들의 값에 따라서 반응 변수들이 범주화된다. 본 논문에서는 이러한 잠재 변수 방법을 확장해 BSAR 방법론에 기반하여 단조증가/감소와 같은 형태제약을 반영할 수 있는 베이지안 이항형 및 순서형 프로빗 준모수 회귀모형에 대해 연구한다. 모의실험을 통하여 이항형 프로빗 준모수 회귀모형과 기존의 다른 모형들 간의 적합결과를 비교하고, 형태 제약에 따른 순서형 프로빗 준모수 회귀모형의 적합결과를 비교 분석하도록 한다. 아울러, 국민건강영양조사 제 7기 1차년도 (2016) 자료(Korean National Health and Nutrition Examination Survey (KNHANES), 2016)를 바탕으로, 본 논문에서 고찰한 이항형 및 순서형 프로빗 준모수 회귀모형을 적용하여, 흡연양태와 커피섭취 간의 관계에 대한 실증적 분석을 수행한다.

• The Journal of Asian Finance, Economics and Business
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• 제9권6호
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• pp.69-79
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• 2022

The purpose of the study is to look into the likelihood of private sector enterprises going bankrupt due to COVID-19 pandemic-related issues. The data for this study was taken from the World Bank's Enterprise Survey, which was intended to assess the impact of the COVID-19 pandemic on the business sector. This study uses the Ordinal Logit Method to analyze the model with dependent variables having ordinal values. The determinants reflect business performance, innovation, business relationships, and government support. According to the estimation results, a lower probability of business closures, illiquidity, and payment delays are found in businesses that maintain sales growth, operating hours, temporary workers, product portfolio, consumer demand, and input supply. Meanwhile, the increase in online business activities and receiving support from financial institutions and the government do not help businesses reduce the risk. Moreover, higher survival is found in manufacturing and developing countries. This implies the fragility of businesses in the retail and service sectors, especially for mega-enterprises in developed countries. In addition, the negative impact of the COVID-19 pandemic on businesses in Europe and West Asia is less severe than in other regions. The results imply policies to support the private sector during the pandemic, such as increasing labor market flexibility or rapidly implementing supportive policies.