• 복합신소재구조학회 논문집
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• 제1권2호
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• pp.29-35
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• 2010

탄성계수와 함께 포아송비는 구조의 거동을 결정하는 중요 구조인수중의 하나이다. 따라서 구조응답의 불확실성에 미치는 포아송비의 독립적 영향에 대한 평가가 필요하다. 본 연구에서는 포아송비의 불확실성이 복합적층판의 거동에 미치는 영향을 산정하기 위한 정식화를 제안한다. 포아송비의 영향은 동일 차수인 임의인수의 영향을 포함하는 부행렬을 통하여 얻을 수 있으며, 이는 대상 인수의 평균을 중심으로 한 Taylor전개를 통하여 구할 수 있다. 제안방법의 검증을 위하여 예제 평판을 해석하였고, 그 결과를 몬테카를로 해석에 의한 결과와 비교하였다. 두 방법을 통하여 얻은 결과는 상화 잘 일치하는 결과를 나타내어, 제안한 방법이 적절함을 제시하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제18권5호
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• pp.613-619
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• 2005

Indigenous Yakutian cattle' adaptation to the hardest subarctic conditions makes them a valuable genetic resource for cattle breeding in the Siberian area. Since early last century, crossbreeding between native Yakutian cattle and imported Simmental and Kholmogory breeds has been widely adopted. In this study, variations at 22 polymorphic microsatellite loci in 5 populations of Yakutian, Kholmogory, Simmental, Yakutian-Kholmogory and Yakutian-Simmental cattle were analysed to estimate the genetic contribution of Yakutian cattle to the two hybrid populations. Three statistical approaches were used: the weighted least-squares (WLS) method which considers all allele frequencies; a recently developed implementation of a Markov chain Monte Carlo (MCMC) method called likelihood-based estimation of admixture (LEA); and a model-based Bayesian admixture analysis method (STRUCTURE). At population-level admixture analyses, the estimate based on the LEA was consistent with that obtained by the WLS method. Both methods showed that the genetic contribution of the indigenous Yakutian cattle in Yakutian-Kholmogory was small (9.6% by the LEA and 14.2% by the WLS method). In the Yakutian-Simmental population, the genetic contribution of the indigenous Yakutian cattle was considerably higher (62.8% by the LEA and 56.9% by the WLS method). Individual-level admixture analyses using STRUCTURE proved to be more informative than the multidimensional scaling analysis (MDSA) based on individual-based genetic distances. Of the 9 Yakutian-Simmental animals studied, 8 showed admixed origin, whereas of the 14 studied Yakutian-Kholmogory animals only 2 showed Yakutian ancestry (>5%). The mean posterior distributions of individual admixture coefficient (q) varied greatly among the samples in both hybrid populations. This study revealed a minor existing contribution of the Yakutian cattle in the Yakutian-Kholmogory hybrid population, but in the Yakutian-Simmental hybrid population, a major genetic contribution of the Yakutian cattle was seen. The results reflect the different crossbreeding patterns used in the development of the two hybrid populations. Additionally, molecular evidence for differences among individual admixture proportions was seen in both hybrid populations, resulting from the stochastic process in crossing over generations.