• 제목/요약/키워드: Meta-model

검색결과 970건 처리시간 0.029초

Beta-Meta: a meta-analysis application considering heterogeneity among genome-wide association studies

  • Gyungbu Kim;Yoonsuk Lee;Jeong Ho Park;Dongmin Kim;Wonseok Lee
    • Genomics & Informatics
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    • 제20권4호
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    • pp.49.1-49.7
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    • 2022
  • Many packages for a meta-analysis of genome-wide association studies (GWAS) have been developed to discover genetic variants. Although variations across studies must be considered, there are not many currently-accessible packages that estimate between-study heterogeneity. Thus, we propose a python based application called Beta-Meta which can easily process a meta-analysis by automatically selecting between a fixed effects and a random effects model based on heterogeneity. Beta-Meta implements flexible input data manipulation to allow multiple meta-analyses of different genotype-phenotype associations in a single process. It provides a step-by-step meta-analysis of GWAS for each association in the following order: heterogeneity test, two different calculations of an effect size and a p-value based on heterogeneity, and the Benjamini-Hochberg p-value adjustment. These methods enable users to validate the results of individual studies with greater statistical power and better estimation precision. We elaborate on these and illustrate them with examples from several studies of infertility-related disorders.

Non-Identical Parallel Machine Scheduling with Sequence and Machine Dependent Setup Times Using Meta-Heuristic Algorithms

  • Joo, Cheol-Min;Kim, Byung-Soo
    • Industrial Engineering and Management Systems
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    • 제11권1호
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    • pp.114-122
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    • 2012
  • This paper considers a non-identical parallel machine scheduling problem with sequence and machine dependent setup times. The objective of this problem is to determine the allocation of jobs and the scheduling of each machine to minimize makespan. A mathematical model for optimal solution is derived. An in-depth analysis of the model shows that it is very complicated and difficult to obtain optimal solutions as the problem size becomes large. Therefore, two meta-heuristics, genetic algorithm (GA) and a new population-based evolutionary meta-heuristic called self-evolution algorithm (SEA), are proposed. The performances of the meta-heuristic algorithms are evaluated through compare with optimal solutions using randomly generated several examples.

The RTEL1 rs6010620 Polymorphism and Glioma Risk: a Meta-analysis Based on 12 Case-control Studies

  • Du, Shu-Li;Geng, Ting-Ting;Feng, Tian;Chen, Cui-Ping;Jin, Tian-Bo;Chen, Chao
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권23호
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    • pp.10175-10179
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    • 2015
  • Background: The association between the RTEL1 rs6010620 single nucleotide polymorphism (SNP) and glioma risk has been extensively studied. However, the results remain inconclusive. To further examine this association, we performed a meta-analysis. Materials and Methods: A computerized search of the PubMed and Embase databases for publications regarding the RTEL1 rs6010620 polymorphism and glioma cancer risk was performed. Genotype data were analyzed in a meta-analysis. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association. Sensitivity analyses, tests of heterogeneity, cumulative meta-analyses, and assessments of bias were performed in our meta-analysis. Results: Our meta-analysis confirmed that risk with allele A is lower than with allele G for glioma. The A allele of rs6010620 in RTEL1 decreased the risk of developing glioma in the 12 case-control studies for all genetic models: the allele model (OR=0.752, 95%CI: 0.715-0.792), the dominant model (OR=0.729, 95%CI: 0.685-0.776), the recessive model (OR=0.647, 95%CI: 0.569-0.734), the homozygote comparison (OR=0.528, 95%CI: 0.456-0.612), and the heterozygote comparison (OR=0.761, 95%CI: 0.713-0.812). Conclusions: In all genetic models, the association between the RTEL1 rs6010620 polymorphism and glioma risk was significant. This meta-analysis suggests that the RTEL1 rs6010620 polymorphism may be a risk factor for glioma. Further functional studies evaluating this polymorphism and glioma risk are warranted.

국방핵심기술 연구개발 사업의 평가 시스템 개선에 관한 연구 (The Study on Improvement of Evaluation System for National Defense Core Technology R&D Projects)

  • 김찬수;조규갑
    • 기술혁신연구
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    • 제15권1호
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    • pp.87-113
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    • 2007
  • For the realization of the national self-defense, the trend of the defense R&D projects becomes global and diverse with the increase of their budget. Thus, for the effective execution of the budget and the successful performance of the projects, the importance of selection, management and evaluation of the R&D projects is emphasized. This study suggests the applicability of a meta-evaluation model for the realization of the successful defense R&D project evaluation system. This study focused on the development of the meta-evaluation model design which can be applicable to the national defense R&D projects. Using the proposed meta-evaluation model, we propose a technique to enhance the fairness and the reliability of the national defense R&D projects evaluation system.

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준모수적 계층적 선택모형에 대한 베이지안 방법 (A Bayesian Method to Semiparametric Hierarchical Selection Models)

  • 정윤식;장정훈
    • 응용통계연구
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    • 제14권1호
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    • pp.161-175
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    • 2001
  • 메타분석(Meta-analysis)은 서로 독립적으로 연구되어진 결과들을 전체적인 하나의 결과로 도출하기 위해 사용되어지는 통계적 방법이다. 이러한 통계적 방법을 설명할 모형으로는 선택모형(selection model)을 포함한 계층적 모형(hierarchical model)을 사용하며, 이러한 모형들은 베이지안 메타분석에 유용한 것으로 알려져 있다. 그러나, 메타분석의 자료들은 일반적으로 출판편의(publication bias)를 갖고 있으므로 이를 극복하고자 가중함수(weight function)를 이용하여 분포함수를 새롭게 정의하여 사용한다. 최근에 Silliman(1997)은 계층적 모형(hierarchical model)에 가중함수를 첨부한 계층적 선택모형(hierarchical selection model)을 정의하고 모수적 베이지안 방법을 제시하였다. 본 연구에서는 미관측된 연구효과에 디리슈레 과정 사전분포(Dirichlet process prior)를 적용한 준모수적 계층적 선택모형(semiparametric hierarchical selection models)을 소개한다. 여기서 제시된 준모수적 계층적 선택모형을 베이지안 방법으로 추정하기 위하여 마코프 연쇄 몬테칼로(Markov chain Monte Carlo)방법을 이용한다. 제시된 방법을 적용하기 위하여 실제 자료(Johnson, 1993)인 충치를 예방하기 위한 두 가지의 예방약의 효과에 대한 차이를 비교하기 위해 얻어진 12개의 연구를 이용하여 메타분석을 한다.

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MetaFluxNet: a program for metabolic flux analysis (MFA)

  • Yun, Hong-Soek;Lee, Dong-Yup;Lee, Sang-Yup;Park, Sunwon
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2002년도 ICCAS
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    • pp.57.3-57
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    • 2002
  • 1. Introduction 2. General flux balance model 3. MetaFluxNet 3.1 Overview of MetaFluxNet 3.2 Project file format 3.3 Construction of metabolite reaction model 3.4 Metabolic flux analysis using linear programming 3.5 Visualization of MFA results 4. Conclusion and plan 5. Acknowledgement. References.

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병렬 유전 알고리즘 기반 meta-유전 알고리즘을 이용한 교차율과 돌연변이율의 최적화 (Optimization of Crossover and Mutation Rate Using PGA-Based meta-GA)

  • 김문환;박진배;이연우;주영훈
    • 한국지능시스템학회:학술대회논문집
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    • 한국퍼지및지능시스템학회 2002년도 추계학술대회 및 정기총회
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    • pp.375-378
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    • 2002
  • In this paper we propose parallel GA to optimize mutation rate and crossover rate using server-client model. The performance of GA depend on the good choice of crossover and mutation rates. Although many researcher has been study about the good choice, it is still unsolved problem. proposed GA optimize crossover and mutation rates trough evolving subpopulation. In virtue of the server-client model, these parameters can be evolved rapidly with relatively low-grade

축차적 반응표면 분석을 통한 M&S 메타모형 구축에 관한 사례 연구 (A Case Study for Finding an Efficient M&S Meta Model through Sequential Response Surface Methodology)

  • 김상익;김용대;임용빈;최기헌;김정은
    • 품질경영학회지
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    • 제40권1호
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    • pp.49-59
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    • 2012
  • In computer simulation models the output from the computer code is often deterministic, i.e., running the code twice with the same values for the input variables would give the same output. It is discussed why the response surface method with polynomial approximation for the true response function is a good approximation to the computer experiments model. A sequential strategy to find the proper reduced quadratic polynomial model is illustrated with a case study in the military war game computer simulation model.

XRCC1-77T>C Polymorphism and Cancer Risk: A Meta-analysis

  • Wang, Yong-Gang;Zheng, Tian-Ying
    • Asian Pacific Journal of Cancer Prevention
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    • 제13권1호
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    • pp.111-115
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    • 2012
  • Variants of X-ray repair cross-complementing group 1 (XRCC1) are involved in the development of cancer, but studies investigating the association of XRCC1-77T>C polymorphism with cancer risk have reported conflicting results. To clarify the effect of the XRCC1 -77T>C polymorphism on cancer risk, we performed a meta-analysis by conducting searches of the published literature in PubMed, Embase and CBM databases. Finally, 13 studies were included into our meta-analysis, involving a total of 11, 678 individuals. Subgroup analyses were performed by ethnicity and cancer type. The results of this meta-analysis showed that there was significant association between the C variant of XRCC1-77T>C polymorphism and cancer risk in all four genetic comparison models (ORC vs. T =1.19, 95%CI 1.07-1.31, P = 0.001; OR homozygote model =1.28, 95%CI 1.07-1.52, P = 0.007; OR recessive genetic model =1.22, 95%CI 1.04-1.44, P = 0.015; OR dominant model =1.21, 95% CI 1.07-1.35, P = 0.001). In the subgroup analyses based on ethnicity, the association was still significant in the Asian population (all p values<0.001), but not in the Caucasian population (all p values > 0.05). Thus, the XRCC1 -77T>C polymorphism is associated with cancer risk, and individuals with XRCC1 -77C variant have a significantly higher cancer risk, particularly in the Asian population.