共查询到20条相似文献，搜索用时 31 毫秒
1.
First,in this paper, the fuzzy cycle matroids are constructed from fuzzy graphs and their properties are discussed;Then,the fuzzy isomorphism of fuzzy matroids is defined. On the basis of a careful discussion of the fuzzy inomorphic properties,we generalize fuzzy cycle matroids to define fuzzy graphic matroids; At last, with the help of a good-cycle concept of fuzzy cycle matroids,a necessary and sufficient condition for a fuzzy matrids to be a fuzzy graphic matroids is given. 相似文献
2.
We have discussed the structure of fuzzy matroids.The concept of fuzzy dependence of fuzzy matroids is provided through the generization of element and set in matroid theory,the properties and the conditions of fuzzy dependence are given.Then some properties of fuzzy dependences are studied.A fuzzy_closure axiom of fuzzy matroids is given,which will be significant to further study of matroid's inbeing and to perfection of matroid theory. 相似文献
3.
The structure and properties of fuzzy matroids are investigated further. By generalizing the idea of crisp matroid sums to fuzzy matroid, the fuzzy matroid sum is defined. The properties of fuzzy matroid sums are studied in detail, and the comparison of properties between the crisp and fuzzy matroid sums is taken in. Particularly, several results, which are important to study the structure of fuzzy matroids, are obtained for close and regular fuzzy matroids. 相似文献
4.
Fuzzy circuit is a fundamental conception of fuzzy matroid and it plays an important role in fuzzy matroid. Using fundamental sequence and induced matroid sequence of fuzzy matroid, the fuzzy circuits of closed fuzzy matroids are studied and some results are found out about fuzzy circuits, I which are the necessary and sufficient conditions of elementary fuzzy circuit for fuzzy matroids or closed fuzzy matroids;the property of elementary fuzzy circuit for closed fuzzy ma- troids;the necessary and sufficient conditions of fuzzy circuit for closed fuzzy matroids. These results are helpful to find out fuzzy circuits from some fuzzy dependent sets of closed fuzzy matroids. 相似文献
5.
Fuzzy matroid is a new fuzzy system originated with the introduction of notion `fuzzy' into the theory of matroid. Some characteristics of fuzzy dual matroids are discussed according to the concept of fuzzy dual matroid given by Goetschel R.J and Voxman W., and then the notion of fuzzy hyperplanes is defined and some of the basic properties of them are investigated. Among these properties three necessary and sufficient conditions are provided from different aspects. Application of fuzzy hyperplanes is provided:fuzzy cloed sets always can be stated by the finite fuzzy hyperplanes. 相似文献
6.
The authors study the properties and structures of fuzzy closed sets and fuzzy hyperplanes.The relationship between the closed set and it's derived matroid's closed set;The intersection of all hyperplanes in matroids is the smallest closed set and its rank is zero;The intersection of all fuzzy hyperplanes in fuzzy matroids is the smallest closed set and its rank is zero;The characteristics of structures of fuzzy closed sets is showed in using mathematical induction;a necessary and sufficient condition has been found in judging whether a fuzzy set is closed or not. 相似文献
7.
LI Sheng_jie 《保鲜与加工》1999,(3):91-96
The relationship between tangent derivative and generalized corvex of set_valued mapping is dealt with in this paper.Then these properties and concepts are applied to optimization problems.Generalized convex properties of perturbation mapping is proved under certain conditims. 相似文献
8.
The structure and properties of fuzzy matroids are investigated further. By generalizing the idea of fuzzy subgraph and fuzzy subspace to fuzzy matroid, some smaller fuzzy matroids are derived from a fuzzy matroid M in the different ways. Moreover, the properties of these new fuzzy matroids are studied, and the relationships among them are also presented. 相似文献
9.
YAN Jin xian 《保鲜与加工》2000,(5):127-130
In strictly convex Banach spaces, by Set valued mappings being monodromied via the optimal approximation for weakly compact convex set and using contraction mapping sequence to approximate nonexpanding mapping.The author has obtained theorems of coupled fixed point for set valued nonexpansive mappings. 相似文献
10.
The phenotypic analysis of field experiments includes information about the experimental design, the randomization structure
and a number of putative dependencies of environment and design factors on the trait investigated. In QTL studies, the genetic
correlation across environments, which arises when the same set of lines is tested in multiple environments, plays an important
role. This paper investigates the effect of model choice on the set and magnitude of detected root QTL in rice. Published
studies on QTLs for root traits indicate that different results are obtained if varying genetic populations are used and also
if different environmental conditions are included. An experiment was conducted with 168 RILs of the Bala × Azucena mapping
population plus parents as checks under four environmental conditions (low light, low nitrogen, drought and a control environment).
We propose a model that incorporates all relevant experimental information into a composite interval mapping approach based
on a mixed model, which especially considers the correlation of genotypes in different environments. An extensive sequential
model selection procedure was applied based on the phenotypic model, using the AIC to determine an appropriate random structure
and Type 3 Wald F-tests for selection of fixed effects. In a first step we checked whether any of the fixed effects and random
(nested) design effects could be dropped. Secondly, an appropriate covariance structure was chosen for genotype × environment
interaction. In a third step Box-Cox transformations were applied based on residual analysis. We compared profiles of composite
interval mapping scans with and without the inclusion of genotype × environment interaction and the experimental design information.
Some distinct differences in profiles indicate that insufficient modeling of the non-QTL part can lead to an overly optimistic
interpretation of QTL main effects in interval mapping. It is concluded that mixed model QTL mapping offers a reasonable way
to separate environmental and genetic influences in the evaluation of quantitative genes and especially enables a more realistic
assessment of QTL and QTL × environment effects than standard approaches by including all relevant effects. 相似文献
11.
基于株平均值的胚乳性状QTL作图的极大似然方法 总被引：6，自引：2，他引：4
根据三倍体胚乳性状的数量遗传模型,发展出一种新的专用于胚乳性状数量基因座位（QTL）区间作图的统计方法。该方法以分离群体中各植株的分子标记基因型以及植株上若干粒种子胚乳性状的平均值为数据模式,采用基于平均值混合分布理论的极大似然方法进行QTL分析。QTL效应估计通过EM算法实现。由于该方法利用标记基因型内QTL基因型的混合分布特性,因此,它比同样基于株平均值的最小平方QTL分析方法以及迭代重新加权最小平方QTL分析方法具有更高的统计功效和精确度。方法的可行性和有效性通过计算机模拟数据分析得到了进一步验证。 相似文献
12.
数量性状基因定位研究中若干常见问题的分析与解答 总被引：18，自引：2，他引：16
QTL作图是基因精细定位、克隆以及有效开展分子育种的基础,在利用QTL作图开展数量性状基因定位研究的过程中经常会碰到一些问题,与统计方法有关的一些问题包括LOD的统计学意义是什么？检测QTL的可信度和LOD临界值的关系是什么？如何评价不同的QTL作图方法？提高QTL检测效率的途径有哪些？与遗传参数估计有关的一些问题包括QTL的贡献率是如何计算出来的？如何确定QTL有利等位基因的来源？选择基因型分析的有效性如何？复合性状是否适宜于QTL作图？与作图群体及遗传图谱有关的一些问题包括QTL作图群体中表型数据是否要求服从正态分布？加密标记是否可以显著提高QTL检测功效？缺失分子标记对QTL作图有什么影响？奇异分离标记对QTL作图有什么影响？文章试图结合笔者多年研究工作对这12个有共性的常见问题做出分析和解答,以供科研工作者参考。 相似文献
13.
四种不同QTL作图方法的比较研究 总被引：2，自引：0，他引：2
应用区间作图法(IM)、复合区间作图法(CIM)、基于混合线性模型的复合区间作图法(MCIM)和多重区间作图法(MIM)对水稻杂交组合（培矮64S×日本晴）F2群体株高性状进行了QTL作图分析。结果表明，（1）在同一显著水平下(α=0.0023)，4种方法共发现10个QTLs，其中IM法7个，CIM法10个，MCIM法3个，MIM法1个。CIM法的发现能力最强。（2）CIM法发现了IM法发现的全部QTLs，和左端标记的距离也基本一致。（3）4种方法检测到了同一QTL，且共同检测到QTL的贡献率最大。（4）4种方法估计的QTL的平均加性效应ā和显性效应 无显著性差异，同一QTL在显性效应的方向上表现一致。（5）建议使用多种作图方法共同作图，并优先标定共同发现的QTL。 相似文献
14.
电子定位的原理与方法 总被引：1，自引：1，他引：0
电子定位技术是一门新近发展起来的基于生物信息学的DNA序列或基因定位技术,与传统的定位技术相比具有简便快捷、成本低的优点。本文系统的介绍了该技术的基本原理,并通过举例说明该技术的应用方法。 相似文献
15.
The traditional method of generating pseudorandom phase vector through a linear feedback shift register (LFSR) and a pre set combination of taps in transform domain communication system(TDCS) was studied. Based on the requirements of the pseudorandom phase vector in TDCS, a new method using chaos mapping to generate the pseudorandom phases in TDCS was proposed. This method generated binary quantization chaotic sequences by using chaos mapping with different initial values, and then creates a pseudorandom phase vector by using a phase mapper. Finally, the basis function was obtained. The implementation method of chaos mapping and the simulation results regarding the correlation performance for the basis function were discussed in detail. Compared with the basis functions generated by LFSR, the basis functions generated by chaos mapping have better correlation performance. Because many basis functions with small cross correlation coefficients can be generated by chaos mapping, this method is advantageous for multiple access applications. 相似文献
16.
B. G. Sutherland K. R. Tobutt A. Marchese G. Paternoster D. W. Simpson D. J. Sargent 《Plant Breeding》2008,127(5):527-532
Physocarpus opulifolius is a deciduous shrub native to North America belonging to the Spiraeoideae subfamily of the Rosaceae. The cultivars ‘Luteus’ and ‘Diabolo’ are grown in gardens for their ornamental foliage, golden and purple respectively. We developed a linkage map of P. opulifolius with a view to detecting markers for the leaf colour genes, which are under major gene control. A total of 162 molecular markers (128 RAPDs, 27 AFLPs, three RGA, three STS markers and one SSR) and the leaf colour genes Pur and Aur were scored in the Physocarpus progeny and used to create a linkage map covering 586.1 cM over nine linkage groups. There was an average of 18.2 markers per linkage group and a mean linkage group length of 65.1 cM. Both leaf colour genes were mapped. This is the first reported linkage map of a member of the Spireaeoideae and the mapping of a small number of transferable markers has demonstrated its utility to comparative mapping, which will complement existing comparative mapping efforts in other rosaceous subfamilies. 相似文献
17.
Mallikarjuna K. Aradhya Dianne Velasco Ji‐Rui Wang Ramesh Ramasamy Frank M. You Chuck Leslie Abhaya Dandekar Ming‐Cheng Luo Jan Dvorak 《Plant Breeding》2019,138(5):635-646
A genetic linkage map of walnut containing 2,220 single nucleotide polymorphisms (SNPs) in 16 linkage groups (LGs) was constructed using an F1 mapping population from a cross between “Chandler” and “Idaho,” two contrasting heterozygous parents. Five quantitative yield traits, lateral fruitfulness, harvest date and three nut traits (shell thickness, nut weight and kernel fill) were then mapped on to linkage groups. A significant quantitative trait locus (QTL) in LG 11 with negative additive effects suggested heterozygote superiority in the expression of lateral bearing. A set of three QTLs explaining ~10% of the variation in harvest date was located in LG 1. Shell thickness, nut weight and kernel fill were under the control of two to three linked pleiotropic QTLs in LG 1 segregating from “Idaho.” The marginal positive additive effects of QTLs for harvest date, shell thickness and nut weight and small negative additive effects for kernel fill suggested that the QTLs had a marginal effect on the expression of these traits. 相似文献
18.
A set of 75 recombinant inbred lines (RILs) of the ITMI mapping population was grown under field conditions in Gatersleben. The lines were evaluated for the domestication traits pre-harvest sprouting and dormancy (germinability). Main QTLs could be localized for pre-harvest sprouting on chromosome 4AL and dormancy on chromosome 3AL. In addition, 85 Triticum aestivum cv. “Chinese Spring”-Aegilops tauschii introgression lines grown under greenhouse conditions were researched. No QTL could be found for pre-harvest sprouting but a major QTL could be detected for dormancy on chromosome 6DL. 相似文献
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20.
不同统计遗传模型QTL定位方法应用效果的模拟比较 总被引：5，自引：0，他引：5
分子遗传和数量遗传的结合,发展了QTL定位研究。随着定位方法与软件的建立和完善,QTL定位的研究越来越多。准确定位的QTL可用于分子标记辅助选择和图位克隆,而假阳性QTL将误导定位信息的应用。本文分析了迄今主要定位方法(软件)对于各种遗传模型数据的适用性。应用计算机模拟4类遗传模型不同的重组自交系群体(RIL),第一类只包含加性QTL;第二类包含加性和上位性互作QTL;第三类包含加性QTL和QTL与环境互作效应;第四类包含加性、上位性互作QTL和QTL与环境互作效应。每类按模拟QTL个数不同设两种情况,共分为8种数据模型(下称M-1～M-8)。选用WinQTLCart 2.5的复合区间作图(下称CIM)、多区间作图前进搜索(MIMF)、多区间作图回归前进选择(MIMR)、IciMapping 2.0的完备复合区间作图(ICIM)、MapQTL 5.0的多QTL模型(MQM)以及QTLnetwork 2.0的区间作图(MCIM)6种程序对8种不同遗传模型的RIL进行QTL检测。结果表明,不同程序适用的遗传模型范围不同。CIM和MQM只适于检测第一类模型;MIMR、MIMF和ICIM只适于检测第一类和第二类模型;只有MCIM适于检测所有4类遗传模型;因而不同遗传模型数据的最适合检测程序不同。由于未知实际数据的遗传模型,应采用在复杂模型程序,如QTLnetwork 2.0,扫描基础上的多模型QTL定位策略,对所获模型用相应模型软件进行验证。 相似文献