• The Korean Journal of Applied Statistics
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• v.35 no.1
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• pp.131-146
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• 2022

Logit models are commonly used to predicting and classifying categorical response variables. Most Bayesian approaches to logit models are implemented based on the Metropolis-Hastings algorithm. However, the algorithm has disadvantages of slow convergence and difficulty in ensuring adequacy for the proposal distribution. Therefore, we use auxiliary mixture sampler proposed by Frühwirth-Schnatter and Frühwirth (2007) to estimate logit models. This method introduces two sequences of auxiliary latent variables to make logit models satisfy normality and linearity. As a result, the method leads that logit model can be easily implemented by Gibbs sampling. We applied the proposed method to diabetes data from the Community Health Survey (2020) of the Korea Disease Control and Prevention Agency and compared performance with Metropolis-Hastings algorithm. In addition, we showed that the logit model using auxiliary mixture sampling has a great classification performance comparable to that of the machine learning models.

• The Korean Journal of Applied Statistics
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• v.10 no.2
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• pp.375-384
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• 1997

In this paper, chain-shaped multi-level skip-lot sampling plan is designed, which is a normal inspection plan between Choi(1993)'s tightened inspection plan and Choi(1995)'s reduced inspection plan. In every skipping inspection of the proposed plan, when designed numbers of consecutively inspected lots are accepted, switch to the next skipping inspection, and when a lot is rejected, switch to the skipping inspection of two-level lower. Also, the formulae of the operating chareacteristic function, average sampling number and average outgoing quality for the proposed skip-lot sampling plan are derived using the morkov chain approach and their properties are studied and graphically compared with those of the other multi-level skip-lot sampling plans.

• Korean Journal of Poultry Science
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• v.49 no.4
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• pp.281-286
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• 2022

This study was conducted to investigate the detection rate and serotypes of Salmonella spp. in conventional and welfare poultry farms. Ten welfare (five layer and five broiler) and 15 conventional farms (five layer and ten broiler farms) were visited to collect environmental samples for identification and serotyping of Salmonella spp. The detection rate of Salmonella spp. was higher in the welfare farms than in conventional farms in both layer and broiler farms. In layer farms, Salmonella spp. was detected in 0.76% (1 out of 130) of samples from one of five welfare layer farms, but was not detected in the five in conventional layer farms. No significan ifference (P>0.05) was observed between the welfare and conventional layer farms. In broiler farms, Salmonella spp. was detected in 10.5% (21 out of 200) of samples from four of five welfare broiler farms and 3.5% (7 out of 200) of samples from five of ten conventional broiler farms, and a significant difference (p <0.05) was observed between the welfare and conventional broiler farms. Among 29 Salmonella spp. isolates, five isolates were serotyped to Salmonella enterica subsp. Enteritidis (n=2), Salmonella enterica subsp. Grampian (n=1), Salmonella enterica subsp. Virchow (n=1), and Salmonella enterica subsp. Senftenberg (n=1). These results suggest that microbial risks could be higher in welfare farms than in conventional farms due to easy access to open-air areas, environmental enrichment, and reduced use of antibiotics. Therefore, continuous monitoring and surveillance for Salmonella spp. is necessary to improve the microbiological safety of poultry meat.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.119-123
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• 2009

Recently, a MEMS gyroscope has been broadly fabricated and used due to development of a micromachining. However, there is a difference between the modeling design and the actual product and this difference can lead to the performance variation of a MEMS gyroscope. A classical design method does not exactly estimate the performance of a MEMS gyroscope. Therefore a design process considering the design variable uncertainty has to be employed to design MEMS gyroscope model. In this paper, the equation of motion of a MEMS gyroscope model is obtained to analyze the performance of a MEMS gyroscope and the effects of the design variables on the MEMS gyroscope performance are investigated. Finally the performance of MEMS gyroscope is estimated through a statistical analysis based on sample statistics.

• The Korean Journal of Applied Statistics
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• v.27 no.2
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• pp.263-275
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• 2014

The present study used a hierarchical Bayesian approach was used to develop a mixed effect model to describe the transitional behavior of subjects in time nonhomogeneous Markov chains. The posterior distributions of model parameters were not in analytically tractable forms; subsequently, a Gibbs sampling method was used to draw samples from full conditional posterior distributions. The proposed model was implemented with real data.

• The Korean Journal of Applied Statistics
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• v.28 no.3
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• pp.371-383
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• 2015

Use of radiocarbon dating is increasing for chronology; however, its variability and discrepancy with existing chronologies can cause doubts in regards to credibility. In this paper, we explore factors that influence radiocarbon dating variabilities. We obtained estimated radiocarbon ages by sending identical samples to several labs multiple times. A Bayesian method was used to analyze the obtained data. From the analysis, we conclude that some factors (such as type of labs and megasamples) can induce variability when estimating radiocarbon age. We identify the size of variability caused by each factor and analyze the estimated variability in each lab corresponds with the reported variability.

• Communications of Mathematical Education
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• v.8
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• pp.279-286
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• 1999

수학 통계용 그래픽 계산기와 통계 자료 분석용 소프트웨어를 활용하는 외국과 국내의 통계 교육의 ·추세를 소개한다. 그리고 통계 자료 분석용 소프트웨어인 Statistica의 특징을 요약한 다음 통계학을 효과적으로 교육하기 위하여 Statistica에서 제공되는 Statistica Basic Language로 프로그램한 세 가지 모듈을 제시한다. 프로그램을 입력하는 과정을 간단히 설명한 후 각 모듈을 소개한다. 처음 모듈은 숫자 값으로 표현되는 계량 자료에 대한 단순 통계량들을 구하기 위하여 분석하려는 원시 자료를 Sprea-dsheet에 입력한 다음 Statistica Basic Language로 프로그램한 모듈을 실행시킴으로써 한 번에 입력 자료에 대한 단순 통계량의 결과들을 볼 수 있도록 하였다. 둘째로 1에서 100까지 숫자들을 단순 랜덤 비복원 추출하는 과정을 프로그램한 모듈을 제시하였다. 마지막으로 프로그램한 모듈에서 제시되는 윈도우에 균일 분포에서 단순 랜덤 복원 추출하기 위한 표본의 크기와 샘플링 반복 횟수를 입력하면 표본 평균의 도수분포표와 도수분포도가 작성되어 표본 평균의 분포가 중심극한정리를 따르는가를 확인하였다.

• Industry Promotion Research
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• v.8 no.1
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• pp.111-117
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• 2023

Sampling inspection methods for quality control have been proposed a lot in the industry. However, the sampling inspection method for reliability, which is a quality over time, has been relatively less presented, and there are not many literatures that are clearly summarized. Therefore, this paper focuses on the reliability conformity test to verify that the reliability evaluation scale value of the target is satisfied during the reliability test. To this end, first, we look at the conditions that both consumers and producers can satisfy in terms of the OC curve and find out what sampling methods satisfy the desired level of producer risk and consumer risk. Next, two methods of the reliability sampling methods such as attribute and variable reliability sampling methods are examined. Specifically, the attribute reliability sampling method is a form of sampling plan where n samples are tested for a certain period of T hours and the lot is accepted if the number of failures is less than or equal to a certain number c. On the other hand, the variable reliability sampling method is a form of sampling plan where the lot is accepted if the reliability evaluation scale such as MTBF satisfies a certain standard. Both sampling plans may also use inspection tables.

• The Korean Journal of Blood Transfusion
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• v.23 no.2
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• pp.162-168
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• 2012

Background: Potassium, the most common cation in the intracellular space, plays a critical role in our physiology. Potassium imbalance may cause life-threatening problems, ranging from general weakness to cardiac arrest due to ventricular fibrillation. For emergency physicians, detection of such derangement within a short period of time is of critical importance. In this study, we wanted to determine whether analysis of whole blood samples can be used as a screening tool for potassium imbalance by comparative analysis of whole blood and serum samples. Methods: Two samples were drawn from 227 patients. The whole blood sample was taken from the radial artery and contained in a commercially available arterial blood collection syringe with a lithium-heparin coating. The serum sample was contained in a commercially available vacuum bottle in a non-additive silicone coated tube and transported to the laboratory. The study population was divided into three groups, patients with normal whole blood potassium, patients with decreased whole blood potassium, and patients with elevated whole blood potassium. Potassium levels for each group were coupled with serum potassium levels and compared. Results: No significant difference in potassium values was observed between whole blood and serum samples (P<0.05). Strong associations were observed among the three groups (normal range, hypokalemia, and hyperkalemia group). Compared to the normal group (r=0.851), the hyperkalemia group showed a stronger association between variables (r=0.897), and the hypokalemia group showed a weaker association (r=0.760). Their correlation coefficients were highly significant (P<0.05). Conclusion: Our study illustrates that point-of-care testing using whole blood with whole blood can be a reliable screening tool when treating patients with suspicious potassium abnormality, especially in hyperkalemia patients.

• 한국공간정보시스템학회:학술대회논문집
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• 2005.05a
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• pp.15-20
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• 2005

기존의 GIS와 지구통계기법을 결합한 연구들은 GIS 데이터베이스로 구축될 자료를 생성하기 위해 2차원 접근방식을 이용해왔다. 그러나 실제 현장 샘플 자료들은 대부분 3차원 공간에 분포하기 때문에 2차원 지구통계기법을 적용하는 것은 실제 자료가 가지고 있는 3차원 위치정보를 정확히 반영할 수 없는 한계가 있다. 본 연구에서는 GIS 기반 자료에 3차원 지구통계기법을 적용하여 공간변수를 예측하고, 생성된 공간변수를 다시 GIS로 반환하여 데이터베이스로 구축하는 결합 모델을 개발하였다. 3차원 지구통계기법을 결합한 결과 보다 정확한 공간변수 예측을 확인할 수 있었고, 그 결과를 GIS에서 다시 활용할 수 있었다.