• Title/Summary/Keyword: Nested Factors

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Generation of Split Plot Design of Fixed Factors by Random, Crossed, and Nested Models (랜덤, 교차, 지분인자 모형에 의한 고정인자 분할구 실험설계의 생성)

  • Choi, Sung-Woon
    • Proceedings of the Safety Management and Science Conference
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    • 2011.04a
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    • pp.487-493
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    • 2011
  • The paper reviews three Split Plot Designs (SPDs) of fixed factors, and those are SPD (RCBD, RCBD), SPD (CRD, RCBD) and SBD (Split Block Design). RCBD (Randomized Complete Block Design) and CRD (Completely Randomized Design) are used to deploy whole plot and sub plot. The models explained in this study are derived from random, crossed and nested models.

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A Mixed Model for Nested Structural Repeated Data (지분구조의 반복측정 자료에 대한 혼합모형)

  • Choi, Jae-Sung
    • The Korean Journal of Applied Statistics
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    • v.22 no.1
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    • pp.181-188
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    • 2009
  • This paper discusses the covariance structures of data collected from an experiment with a nested design structure, where a smaller experimental unit is nested within a larger one. Due to the nonrandomization of repeated measures factors to the nested experimental units, compound symmetry covariance structure is assumed for the analysis of data. Treatments are given as the combinations of the levels of random factors and fixed factors. So, a mixed-effects model is suggested under compound symmetry structure. An example is presented to illustrate the nesting in the experimental units and to show how to get the parameter estimates in the fitted model.

Power Comparison in a Balanced Factorial Design with a Nested Factor

  • Choi, Young-Hun
    • Journal of the Korean Data and Information Science Society
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    • v.19 no.4
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    • pp.1059-1071
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    • 2008
  • In a balanced factorial design with a nested factor where crossed factors as well as a nested factor exist simultaneously, powers of the rank transformed FR statistic for testing the main, nested and interaction effects are superior to those of the parametric F statistic. In heavy tailed distributions such as exponential and double exponential distributions, powers of the FR statistic show much higher level than those of the F statistic. Further powers of the F and FR statistic for testing the main effect show the highest level in an absolute size as compared with powers of the F and FR statistic for testing the nested and interaction effects. However powers of the FR statistic for testing the nested and interaction effects rather than the main effect are greater in a relative size than powers of F statistic for the all population distributions.

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Variance Components of Nested Designs (지분계획의 분산성분)

  • Choi, Jaesung
    • The Korean Journal of Applied Statistics
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    • v.28 no.6
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    • pp.1093-1101
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    • 2015
  • This paper discusses nested design models when nesting occurs in treatment structure and design structure. Some are fixed and others are random; subsequently, the fixed factors having a nested design structure are assumed to be nested in the random factors. The treatment structure can involve random and fixed effects as well as a design structure that can involve several sizes of experimental units. This shows how to use projections for sums of squares by fitting the model in a stepwise procedure. Expectations of sums of squares are obtained via synthesis. Variance components of the nested design model are estimated by the method of moments.

A Continuation-Ratio Logits Mixed Model for Structured Polytomous Data

  • Choi, Jae-Sung
    • Journal of the Korean Data and Information Science Society
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    • v.17 no.1
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    • pp.187-193
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    • 2006
  • This paper shows how to use continuation-ratio logits for the analysis of structured polytomous data. Here, response categories are considered to have a nested binary structure. Thus, conditionally nested binary random variables can be defined in each step. Two types of factors are considered as independent variables affecting response probabilities. For the purpose of analyzing categorical data with binary nested strutures a continuation-ratio mixed model is suggested. Estimation procedure for the unknown parameters in a suggested model is also discussed in detail by an example.

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Logistic regression model for major separation rate

  • Choi, Jae-Sung
    • Journal of the Korean Data and Information Science Society
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    • v.13 no.2
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    • pp.129-138
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    • 2002
  • This paper deals with logistic regression models for analysing separation rates from majors. The model building procedure shows how to incoporate the effects of some factors causing from three-way nested sampling scheme and discusses what type of characteristics as independent variables directly affecting the rates should be considered.

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A cumulative logit mixed model for ordered response data

  • Choi, Jae-Sung
    • 한국데이터정보과학회:학술대회논문집
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    • 2004.04a
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    • pp.121-126
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    • 2004
  • This paper discusses about how to build up a mixed-effects model using cumulative logits when there are some factors are fixed and others are random. Random factors are assumed to be coming from a two-way nested design for choosing individuals or experimental units to apply treatments. Estimation procedure for the unknown parameters in a suggested model is also discussed by an illustrated example.

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Estimation of Gauge R&R by Variance Components of Measurement ANOVA (측정 ANOVA의 분산성분에 의한 게이지 R&R 추정)

  • Choi, Sung-woon
    • Journal of the Korea Safety Management & Science
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    • v.12 no.1
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    • pp.199-205
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    • 2010
  • The research proposes the three-factor random measurement models for estimating the precision about operator, part, tool, and various measurement environments. The combined model with crossed and nested factors is developed to analyze the approximate F test by degrees of freedom given by Satterthwaite and point estimation of precisions from expected mean square. The model developed in this paper can be extended to the three useful models according to the type of nested designs. The study also provides the three-step procedures to evaluate the measurement precisions using three indexes such as SNR(Signal-To-Noise Ratio), R&R TR(Reproducibility&Repeatability-To-Total Precision Ratio), and PTR(Precision-To-Tolerance Ratio), The procedures include the identification of resolution, the improvement of R&R reduction, and the evaluation of precision effect.

Detection of Coinfection and Persistent Infection of Adenovirus and Varicella-Zoster Virus in Synovial Fluids from Synovitis Patients by Nested-PCR (Nested 중합효소연쇄반응을 이용하여 활막염 환자의 관절액으로부터 아데노바이러스와 대상포진바이러스의 이중감염과 지속감염의 검출)

  • Park, Hae-Kyung;Woo, So-Youn;Kim, Hyun-Jin
    • The Journal of Korean Society of Virology
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    • v.30 no.3
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    • pp.179-187
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    • 2000
  • The etiology of rheumatic arthritis (RA) is associated with a number of genetic and environmental factors, but is not definitively elucidated. Recently, more attention has been paid to the possibility of microbial etiology in the pathogenesis of RA, because many different infectious agents have been reported to precede the onset or exacerbation of RA. Adenovirus (ADV) may be one cause of persistent or recurrent inflammatory arthritis. Varicella zoster virus (VZV) arthritis is detected frequently in RA patients treated with low dose methotrexate. The demonstration of simultaneous presence of both viral agents of specific viral nucleic acid in synovial fluids from synovitis patients would provide more direct evidence for arthritis etiological relationship, but there are no confirmed results. Therefore, we studied the ability of adenovirus and VZV to establish coinfection and persistent infection in synovial fluid from synovitis patients. The presence of viral agents in the synovial fluid demonstrated by isolation of cell culture, enzyme immunoassay and nested-PCR. The synovial fluids were also investgated for the presence of viral nucleic acid by nested-PCR using specific primer. ADV produced 220 bp and VZV produced 447 bp by each nested-PCR with specific primers. We detected 4/6 cases (66.7%) with persistent infection of ADV and 5/6 cases (83.3%) of VZV with 13 synovial fluids (between 7 to 52 day intervals) from synovitis patients by monoclonal ErA and nested-PCR. 21/28 cases (75%) with coinfection of adenovirus and VZV with synovial fluids from synovitis patients by nested-PCR. ADV and VZV coinfection and persistent infection of synovial fluids may provide a chronic antigenic stimuli to the immune system therefore provoking a continuing inflammatory response and caused the possibility of synovitis and arthritis.

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Derivation of Expected Mean Squares (EMS) Using Venn Diagram by the Type of Experimental Design (실험설계 유형별 Venn Diagram을 이용한 EMS 도출)

  • Choi, Sung-Woon
    • Proceedings of the Safety Management and Science Conference
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    • 2011.04a
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    • pp.695-699
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    • 2011
  • The study presents an efficient design method of Venn Diagram that can be used when implementing the quality design of experiments based on generalizability theory. The paper examines four mixed and combined models that are designed by fixed factor, random factor, crossed factor and nested factor. The models considered in this research are $A^*{\times}B^*{\times}C$, (B: $A^*$)${\times}C$, $A{\times}B{\times}C$ and (B: A)${\times}C$.

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