• Communications for Statistical Applications and Methods
• /
• 제17권6호
• /
• pp.791-801
• /
• 2010

마이크로데이터 제공시 발생될 수 있는 노출(disclosure)과 노출위험을 나타내는데 사용되는 측도인 유일성(uniqueness) 그리고 모집단 유일성의 개수를 추정하기 위한 초모집단 모형으로 Multinomial-Dirichlet 모형, Takemura의 Poisson-Gamma 모형, Modified Multinomial-Dirichlet 모형, Bethlehem의 Poisson-Gamma 모형을 다룬다. 이 4개의 모형에 대해 마이크로데이터 제공에 따른 임계모집단 크기(critical population size)를 결정한다.

• 한국통계학회:학술대회논문집
• /
• 한국통계학회 2005년도 춘계 학술발표회 논문집
• /
• pp.239-244
• /
• 2005

In this paper, we examine the problem of estimating the sensitive characteristics and behaviors in a multinomial randomized response (RR) model. We analyze this problem through a Bayesian perspective and develop a Bayesian multinomial RR model in survey study. The Bayesian inference of multinomial RR model is a new approach to RR models.

• Journal of the Korean Statistical Society
• /
• 제13권1호
• /
• pp.1-19
• /
• 1984

A random effects model of a one-way layout contingency table is developed using a Dirichlet-multinomial distribution. A test statistic, say $T_k$, is suggested for detecting Dirichlet-multinomial departure from a multinomial distribution. It is shown that the $T_k$ test is asymptotically superior to the classical chi-square test based on the asymptotic relative efficiency. This superiority is further evidenced by a Monte Carlo simulation.

• Communications for Statistical Applications and Methods
• /
• 제14권1호
• /
• pp.121-131
• /
• 2007

In this paper, we examine the problem of estimating the sensitive characteristics and behaviors in a multinomial randomized response model using Bayesian approach. We derived a posterior distribution for parameter of interest for multinomial randomized response model. Based on the posterior distribution, we also calculated a credible intervals and mean squared error (MSE). We finally compare the maximum likelihood estimator and the Bayes estimator in terms of MSE.

• Journal of the Korean Statistical Society
• /
• 제30권3호
• /
• pp.435-451
• /
• 2001

We describe a hierarchical bayesian model to analyze multinomial nonignorable nonresponse data. Using a Dirichlet and beta prior to model the cell probabilities, We develop a complete hierarchical bayesian analysis for multinomial proportions without making any algebraic approximation. Inference is sampling based and Markove chain Monte Carlo methods are used to perform the computations. We apply our method to the dta on body mass index(BMI) and show the model works reasonably well.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제15권5호
• /
• pp.1630-1648
• /
• 2021

Owing to the unprecedented COVID-19 pandemic, the pharmaceutical industry has attracted considerable attention, spurred by the widespread expectation of vaccine development. In this study, we collect relevant topics from news articles related to COVID-19 and explore their links with two South Korean pharmaceutical indices, the Drug and Medicine index of the Korea Composite Stock Price Index (KOSPI) and the Korean Securities Dealers Automated Quotations (KOSDAQ) Pharmaceutical index. We use generalized Dirichlet-multinomial regression (g-DMR) to reveal the dynamic topic distributions over metadata of index values. The results of our analysis, obtained using g-DMR, reveal that a greater focus on specific news topics has a significant relationship with fluctuations in the indices. We also provide practical and theoretical implications based on this analysis.

• Journal of the Korean Data and Information Science Society
• /
• 제23권3호
• /
• pp.587-593
• /
• 2012

We study Bayesian estimates for finite population proportions in multinomial problems. To do this, we consider a three-stage hierarchical Bayesian model. For prior, we use Dirichlet density to model each cell probability in each cluster. Our method does not require complicated computation such as Metropolis-Hastings algorithm to draw samples from each density of parameters. We draw samples using Gibbs sampler with grid method. We apply this algorithm to a couple of simulation data under three scenarios and we estimate the finite population proportions using two kinds of approaches We compare results with the point estimates of finite population proportions and their standard deviations. Finally, we check the consistency of computation using differen samples drawn from distinct iterates.

• 한국컴퓨터정보학회논문지
• /
• 제25권12호
• /
• pp.83-91
• /
• 2020

본 연구에서는 DBpia에 등록된 코로나19 관련 논문을 대상으로 연구 토픽을 밝히고 연구 변화 추세를 검토한다. 잠재 디리슐레 할당(Latent Dirichlet Allocation) 알고리즘을 적용한 결과, 7개의 연구 토픽을 도출하였고, 각 토픽은 "International Dynamics", "Technology & Security", "Psychological Impact", "Biomedical-Related", "Economic Impact", "Online Education", "Religion-Related"에 관한 내용이었다. 또한 다범주 로짓모형을 사용하여 연구 토픽의 추세 변화를 살펴본 결과, 2020년 6월 전에는 국제적 역학관계 및 생물 의학 관련 논문이 주를 이루었다면, 이후에는 다양한 분야로 연구 주제가 확대되었다. 특히 경제적인 영향, 온라인 교육, 심리적인 영향에 관한 연구가 꾸준히 증가함을 확인할 수 있었다. 이러한 결과는 향후 코로나19 관련 공동 연구의 가이드 라인을 제시하고, 활발한 연구 활동을 위한 기초자료로 활용될 수 있을 것이다.

• 한국조사연구학회:학술대회논문집
• /
• 한국조사연구학회 2006년도 춘계학술대회 발표논문집
• /
• pp.131-159
• /
• 2006

This paper consider multinomial group testing which is concerned with classification each of N given units into one of k disjoint categories. In this paper, we propose exact Bayesian, approximate Bayesian, bootstrap methods for estimating individual category proportions using the multinomial group testing model proposed by Bar-Lev et al (2005). By the comparison of Mcan Squre Error (MSE), it is shown that the exact Bayesian method has a bettor efficiency and consistency than maximum likelihood method. We suggest an approximate Bayesian approach using Markov Chain Monte Carlo (MCMC) for posterior computation. We derive exact credible intervals based on the exact Bayesian estimators and present confidence intervals using the bootstrap and MCMC. These intervals arc shown to often have better coverage properties and similar mean lengths to maximum likelihood method already available. Furthermore the proposed models are illustrated using data from a HIV blooding test study throughout California, 2000.

• Communications for Statistical Applications and Methods
• /
• 제21권2호
• /
• pp.135-145
• /
• 2014

The present study surveys Bayesian modeling structure for inferences about transition probabilities of Markov chain. The motivation of the study came from the data that shows transitional behaviors of emotionally disturbed children undergoing residential treatment program. Dirichlet distribution was used as prior for the multinomial distribution. The analysis with real data was implemented in WinBUGS programming environment. The performance of the model was compared to that of alternative approaches.