• 한국데이터정보과학회:학술대회논문집
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• 한국데이터정보과학회 2001년도 추계학술대회
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• pp.13-16
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• 2001

We compare methods for detecting influential observations that have a large influence on the likelihood ratio test statistics that the two sets of variables are uncorrelated with one another. For this purpose we derive results of the deletion diagnostic, the influence function, the standardized influence matrix and the local influence. An illustrative example is given.

• Communications for Statistical Applications and Methods
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• 제20권1호
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• pp.23-28
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• 2013

We propose a version of Cook's distance (called local distance) in the multivariate linear model. The proposed version is a matrix, while the existing version of Cook's distance (called global distance) is a scalar. The existing Cook's distance is the trace of the proposed Cook's distance. In addition, we argue that the proposed Cook's distance has a more natural extension of the Cook's distance in the univariate linear model than the existing Cook's distance. An illustrative example based on a real data set is given.

• Communications for Statistical Applications and Methods
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• 제25권5호
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• pp.523-544
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• 2018

Bivariate distributions play a fundamental role in survival and reliability studies. We consider a regression model for bivariate survival times under right-censored based on the bivariate Kumaraswamy Weibull (Cordeiro et al., Journal of the Franklin Institute, 347, 1399-1429, 2010) distribution to model the dependence of bivariate survival data. We describe some structural properties of the marginal distributions. The method of maximum likelihood and a Bayesian procedure are adopted to estimate the model parameters. We use diagnostic measures based on the local influence and Bayesian case influence diagnostics to detect influential observations in the new model. We also show that the estimates in the bivariate Kumaraswamy Weibull regression model are robust to deal with the presence of outliers in the data. In addition, we use some measures of goodness-of-fit to evaluate the bivariate Kumaraswamy Weibull regression model. The methodology is illustrated by means of a real lifetime data set for kidney patients.

• Communications for Statistical Applications and Methods
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• 제23권3호
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• pp.231-239
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• 2016

A graphical diagnostic method based on multiple case deletions in a regression context is introduced by using the sampling distribution of the difference between two least squares estimators with and without multiple cases. Principal components analysis plays a key role in deriving this diagnostic method. Multiple case deletions of test statistic are also considered when a new observation is fitted to a given regression model. The result is useful for detecting influential observations in econometric data analysis, for example in checking whether the consumption pattern at a later time is the same as the one found before or not, as well as for investigating the influence of cases in the usual regression model. An illustrative example is given.

• 산업경영시스템학회지
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• 제18권33호
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• pp.93-102
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• 1995

In this study we are concerned with the diagnostics method of cross-classified categorical data using logistic regression model of binary response models for cell proportions. under this model, we could examine the goodness-of-fit of the models using Pearson's $x^2$test statistic and likelihood ratio statistic. Under this model, these statistics are assumed that sample survey schemes are with replacement sampling model. But these statistics are often inappropriate for analysing contingency tables consists of complex sampling schemes obtained sample survey data. In this study we are examined diagnostics procedures detecting any outlying cell proportions and influential observations on design space in logistic regression modeltake account of the survey design effects.

• 한국콘텐츠학회논문지
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• 제13권10호
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• pp.574-583
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• 2013

각 지자체가 관리하고 있는 해안지역은 지형적, 문화적, 경제적으로 큰 영향을 미치는 공간으로 변모하고 있다. 이러한 해안 공간에 대하여 최근 들어 공학적 측면과 경제적, 문화적 측면이 융합된 새로운 형태의 연구들이 많이 진행되고 있는 실정이다. 본 연구는 울산 동구에 위치한 일산지 해안에 대한 해안선 변화에 대하여 다중관측 정보를 이용하여 분석하였다. 해안선 분석을 위하여 VRS-RTK(Virtual Reference System by Real-Time Kinematic) 측량, 항공사진, 지상라이다 측량, 그리고 고정기준점에 의한 측량을 실시하였으며, 특히 고정기준점 설치를 통한 해안선 관측과 분석방법을 제시하였다. 다중관측정보를 분석한 결과 일산지의 경우 해안선의 중하단 부분은 침식현상(6~12m)이 나타나고 있으며, 상단부분은 퇴적현상(3~14m)이 나타남을 알 수 있었다.

• 산업공학
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• 제25권1호
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• pp.13-20
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• 2012

Recently, the collaboration among small and medium-sized enterprises(SMEs) has been recognized as an effective competitive tool. As several systems have been developed to boost the collaboration, it is necessary to analyze the effectiveness of the systems in terms of their contribution to enhance operational performance of SMEs through objective and quantitative validation. In particular, the analysis for SMEs rather than large-scaled enterprises has not received much attention due to lack of relevant information and difficulty of collecting data. This paper presents a framework for analyzing the effectiveness of the collaboration support system, called i-manufacturing hub, which has been implemented by Korean government. Identification of influential factors to the effectiveness of collaboration hub, and constructing necessary hypotheses are proposed. To overcome the difficulty in data collection only by means of surveys through subjective questionnaires, we exploit system log data that are generated while SMEs use the system. As an initial phase to analyze the effectiveness through hypothesis validation, we discuss several interesting observations and challenges in the direction of enhancing collaboration among SMEs for better operational performance improvement and more participation in the collaboration hub.

• East Asian Economic Review
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• 제17권2호
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• pp.207-241
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• 2013

The notion of green growth emerged in 2009. Since then, policy makers and practitioners have largely adopted the term. Although rather intermittently, there have been academic observations on green growth, with the term often being cited as a paradigm and a policy guide for generating new sources of growth. The most important reasons for the surge in green growth today as a new trend and an international agenda item are the rather unsatisfactory results and pitfalls of sustainable development, which has failed at promoting a tangible international environmental principle or a concrete policy framework. Green growth has been proposed as an alternative simultaneously to foster the dynamics of global environmental governance and to reinvigorate the world economy. This study examines to what extent green growth plays a complementary role in existing global environmental governance. Available evidence provides reasonable grounds for arguing that a positive outcome may well be expected from the evolution of green growth architecture and followed by practical policies. It became a global agenda out of a few influential national governments' control. However, decision makers in the leading countries, both developed and developing must be willing to continue implementing what has been discussed and agreed thus far, beyond changes in political leadership and administrations.

• Communications for Statistical Applications and Methods
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• 제24권6호
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• pp.605-625
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• 2017

This paper presents proportional odds cure models to allow spatial correlations by including spatial frailty in the interval censored data setting. Parametric cure rate models with independent and dependent spatial frailties are proposed and compared. Our approach enables different underlying activation mechanisms that lead to the event of interest; in addition, the number of competing causes which may be responsible for the occurrence of the event of interest follows a Geometric distribution. Markov chain Monte Carlo method is used in a Bayesian framework for inferential purposes. For model comparison some Bayesian criteria were used. An influence diagnostic analysis was conducted to detect possible influential or extreme observations that may cause distortions on the results of the analysis. Finally, the proposed models are applied for the analysis of a real data set on smoking cessation. The results of the application show that the parametric cure model with frailties under the first activation scheme has better findings.

• 교육시설 논문지
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• 제21권2호
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• pp.25-32
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• 2014

Many Korean university campuses are located on hilly terrain where the hierarchy of the path system is unclear. Therefore, it is difficult to analyze the pedestrian network through space syntax, in which only horizontal direction changes are considered as depths of space. The purpose of this study is to compare pedestrian movement patterns and space syntax analysis in order to find their relevance to each other and the relationship between them. We conducted a survey regarding the most-visited buildings and pathways at S-University, which is located on a hilly area in Seoul. The survey results were compared with the Space Syntax integration map by regression analysis. For the segments where the relationship between pedestrian volume and integration was weak, field observations were conducted. As a result, topographical aspects, functional aspects, and location aspects were observed as the main influential factors. In addition, the research proposes that adding an extra axial line per vertical directional change can potentially compensate for the low relevance of stairs. This study suggests the possibility and the necessity of three-dimensional space syntax programs and emphasizes the importance of campus planning for the pedestrian environment.