• Communications for Statistical Applications and Methods
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• 제1권1호
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• pp.81-86
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• 1994

A Chi-square approximation to the distribution of product of independent Beta variates denoted by U is developed. The distribution is commonly used as a test criterion for the general linear hypothesis about the multivariate linear models. The approximation is obtained by fitting a logarithmic function of U to a Chi-square variate in terms of the first three moments. It is compared with the well known approximations due to Box(1949), Rao(1948), and Mudholkar and Trivedi(1980). It is found that the Chi-square approximation compares favorably with the other three approximations.

• Journal of the Korean Statistical Society
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• 제12권1호
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• pp.24-35
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• 1983

In fitting models to data, selection of the most desirable estimation method and determination of the adequacy of fitted model are the central issues. This paper compares the maximum likelihood estimators and the minimum logit chi-square estimators, both being best asymptotically normal, when logit models are fitted to infant mortality data. Chi-square goodness-of-fit test and likelihood ratio one are also compared. The analysis infant mortality data shows that the outlying observations do not necessarily result in the same impact on goodness-of-fit measures.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.526-531
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• 1992

Partial derivatives are easily computed analytically assuming that all the geometric information is known. However, there are computational difficulties in getting accurate partial derivatives directly from a range image since an image is a discrete version of continuous data contaminated with some noise. In this paper, we develop a general window function to compute partial derivatives based on the least square surface fitting method. A dynamic selective surface fitting method is introduced to make the window less sensitive to noise. Any degree of partial derivative can be obtained by a simple convolution between an image and window functions.

• 천문학회보
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• 제35권2호
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• pp.30.2-30.2
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• 2010

A direct tilted-ring fitting method allows us to investigate kinematic structure of spiral galaxies. By employing the method to high-resolution HI data cubes, we can more easily trace warp characteristics of spiral galaxies than ever. In this contribution, we make use of TiRiFiC to VLA HI data cube of spiral galaxies in Virgo cluster, and present our preliminary yet interesting results. The TiRiFiC (Tilted-Ring-Fitting-Code) is publicly available code that provides 'best-fit' tilted-ring parameters (i.e. position angle and inclination) via chi-square minimization technique. We also discuss possible biases (e.g., resolution dependency) and its effect on our conclusions.

• 정보보호학회논문지
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• 제29권4호
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• pp.795-805
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• 2019

최근 알려지지 않은 공격에 대처하기 위한 네트워크 비정상(anomaly) 탐지 기술에 대한 관심이 한층 높아지고 있다. 이러한 기술 개발을 위해 데이터 마이닝(data mining), 기계학습(machine learning), 그리고 딥러닝(deep learning)등을 활용한 다양한 연구가 진행되고 있다. 본 논문에서는 분류(classification) 문제를 다루는 데이터 마이닝 기술 중 가장 전통적인 방법 중 하나인 의사결정나무(decision tree)를 이용하여 NSL-KDD 데이터 셋을 대상으로 네트워크 비정상 탐지 가능성을 보여준다. 의사결정나무의 과대적합(over-fitting) 단점을 해소하기 위해 카이-제곱(chi-square) 테스트를 통해 최적의 속성 선택(feature selection)을 수행하고, 선택된 13개의 속성을 사용한 의사결정나무 모델 환경에서 NSL-KDD 시험 데이터 셋 KDDTest+에 대해 84% 그리고 KDDTest-21에 대해 70%의 네트워크 비정상 검출 정확도를 보였다. 제시된 정확도는 기존 의사결정나무 모델 적용 시 이들 시험 데이터 셋을 대상으로 알려진 정확도 81% 그리고 64% 수준과 비교해 약 3% 그리고 6% 각각 향상된 결과다.

• ETRI Journal
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• 제33권2호
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• pp.219-229
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• 2011

In this paper, we propose a transformation scheme used to analyze online gaming traffic properties and develop a traffic model. We analyze the packet size and the inter departure time distributions of a popular first-person shooter game (Left 4 Dead) and a massively multiplayer online role-playing game (World of Warcraft) in order to compare them to the existing scheme. Recent online gaming traffic is erratically distributed, so it is very difficult to analyze. Therefore, our research focuses on a transformation scheme to obtain new smooth patterns from a messy dataset. It extracts relatively heavy-weighted density data and then transforms them into a corresponding dataset domain to obtain a simplified graph. We compare the analytical model histogram, the chi-square statistic, and the quantile-quantile plot of the proposed scheme to an existing scheme. The results show that the proposed scheme demonstrates a good fit in all parts. The chi-square statistic of our scheme for the Left 4 Dead packet size distribution is less than one ninth of the existing one when dealing with erratic traffic.

• 대한시과학회지
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• 제20권4호
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• pp.431-442
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• 2018

목적 : 소프트 콘택트렌즈 착용자를 대상으로 착용실태 및 구입현황, 피팅 상태 확인 유무에 따른 자각적 증상, 그리고 베이스커브에 대한 소비자 인식도를 알아보고자 하였다. 방법 : 2018년 6월부터 8월까지 소프트 콘택트렌즈를 구매하기 위하여 서울소재의 안경원 및 렌즈샵에 방문한 사람들을 대상으로 설문조사를 시행하였으며, 총 98부를 분석에 이용하였다. 카이제곱 검정과 Fisher의 정확 검정을 이용하여 피팅 상태 확인(착용감과 관련된 문진, 푸시업 테스트 등) 유무에 따른 자각적 증상(건조함, 빛 번짐, 착용감 불편, 시력저하)을 비교하였으며, 로지스틱 회귀분석을 이용하여 오즈비를 구하였다. 결과 : 소프트 콘택트렌즈를 구입 시 시력검사를 받고 구입한 경우는 안경원은 86.6%, 렌즈샵은 64.7%이었다. 콘택트렌즈를 구입할 때 피팅 상태의 확인을 받지 않은 경우에는 피팅 상태의 확인을 받은 경우에 비해 건조함(오즈비 4.41, 95% 신뢰구간 1.25-15.62)과 착용감 불편(오즈비 2.68, 95% 신뢰구간 1.08-6.64)을 더 많이 경험하는 것으로 나타났다. 또한 콘택트렌즈 착용자의 87.8%가 베이스커브라는 용어를 알지 못하고 있었으며, 콘택트렌즈 구매 시 92.9%가 베이스커브와 관련된 설명을 듣지 못한 것으로 나타났고, 96.9%가 베이스커브 검사를 받은 경험이 없는 것으로 조사되었다. 결론 : 소프트 콘택트렌즈 처방 시 피팅 상태의 확인을 통한 적절한 베이스커브의 변경을 통해 기존 소비자들의 콘택트렌즈의 착용 시 만족도를 향상시켜야 할 것으로 생각된다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제12권2호
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• pp.81-95
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• 2008

In this paper, the negative Polya-Eggenberger distribution has been introduced by compounding negative binomial distribution with beta distribution of I-kind which generates a number of univariate contagious or compound (or mixture of) distributions as its particular cases. The distribution is unimode, over dispersed and all of its positive and negative integer moments exist. The difference equation of the proposed model shows that it is a member of the Ord's family of distribution. Some of its interesting properties have been explored besides different methods of estimation been discussed. Finally, the parameters of the proposed model have been estimated by using a computer programme in R-software. Application of the proposed model to some data, available in the literature, has been given and its goodness of fit demonstrated.

• The International Journal of Costume Culture
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• 제2권2호
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• pp.1-13
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• 1999

This study aimed to give an updated description of general clothing behavior patterns of the Korean elderly women. 430 women over 60 years old residing in Seoul wre surveyed with a questionnaire asking about their daily practices of clothing selection, disposal, recycling, quantity and place of purchase, and their background variables. Data were treated to SPSS for descriptive statistics, Chi-square analysis, ANOVA and Duncan's multiple range test. The result revealed that the wardrobe of the Korean aged women is by now fully oriented toward the western style. The subjects disposed of their clothing mainly because of their body size changes and had elementary fitting problems unsolved. They had clothing recycling experinces and turned out to be inactive clothing consumers with differing shopping places according to the types of clothing items to be purchased. The subjects'age and income level had significant effects on various facets of their clothing behavior.

• 한국의류학회지
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• 제37권3호
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• pp.292-305
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• 2013

This study reported present state of clothing technical designers' work duties and working conditions, so as to suggest effective ways to develop professional training methods for them. Technical designers working for vendors and agents were surveyed as they represent the majority of technical designers in Korean clothing industries. Survey participants were 62 technical designers working for 6 clothing vendors and 2 clothing agents, and the survey closely inspected their work qualifications, duties and responsibilities, working conditions and training conditions. Survey was conducted from June $27^{th}$ to July $17^{th}$, 2012. The questionnaire examined frequency analysis and multiple response analysis using SPSS 19.0 Windows after investigating documents and work fields through personal experiences and interviews from technical designers for data collection and analysis. A chi-square test analyzed the preferred type of fitting for technical designers of vendors and agents. The results showed that 32.3% of those surveyed have more than 7 years of work experience and the highest level of education is predominantly a bachelor's degree (57 people, 91.9%). Among the work responsibilities, respondents did sample measuring more than four times a day. Also, the results showed that technical designers needed to qualify: first 'Fitting Technic', second 'Pattern Correction Capability', and third 'English Skills to Communicate with Buyers'; subsequently, education on several technics (such as measuring, grading, and fitting) were required for the job. Current technical designers answered that they need more various work-related education. However, the analyzed results showed that pre work-related training was insufficient. The data shows that technical designers require re-education in 'Pattern Correction Method' (61.3%) and 'Sewing Education' (64.5%).