基于主成分分析与神经网络的葡萄酒品质评价

此文在主成分分析的基础上,运用人工神经网络对UCI数据库的葡萄酒数据建立了数学模型。仿真实验结果表明该模型是行之有效的方法。     

小麦品质性状的主成分和相关性分析

利用IBM SPSS19.0软件对82个不同小麦品种的品质性状进行了主成分和相关性分析,结果表明:小麦蛋白含量与干面筋和湿面筋间、干面筋和湿面筋间、直链淀粉和支链淀粉间存在0.01水平显著相关;按方差贡献率提取出3个主成分,3个主成分初始特征值累积贡献率达89.683%,根据标准化正交特征向量矩阵,得出3个主成分的表达式和综合模型,通过综合得分的高低,对不同小麦品种的品质性状进行了排序,其中由新疆维吾尔自治区品种审定委员会审定的优势强筋小麦品种"新春21"的得分最高,"巴优1号"的综合得分最低。     

核主成分法的应用

分别利用主成分法和核主成分法,对2010年江苏省13个市的旅游业发展情况进行对比分析,发现核主成法分析的结果更加合理,并分析了原因,最后对江苏未来的旅游业发展提出了建议,供有关部门参考.     

主成分分析在教学管理中的应用

本文用主成分分析的多元统计方法对教学管理中学生总成绩的评定进行了分析和探讨,并通过一个实例给出了这种方法的具体计算,为更客观,更科学地对学生总成绩进行排队提供了理论依据.     

水稻产量影响的主成分分析

利用主成分分析法和回归分析法分析影响水稻区试品种产量的因子,结果表明,影响产量的主成分因子分别是热量、海拔—雨量、穗重和粒数;利用各因子作为自变量,水稻产量作为因变量,进行逐步回归分析,建立一个产量回归方程。方程的相关系数(R)达0.99983,各因子对生产量影响的大小为纬度>有效穗>实粒数>千粒重>年均降雨量。     

葡萄"克伦生"品种抽条原因的主成分分析

河南济源市坡头镇的“克伦生”葡萄生产基地,2006年春季发生较大面积的抽条现象。调查了霜霉病、地势、同龄主干粗度、果实采收期、施基肥与不施基肥、春灌时间等因素对葡萄抽条的影响。通过对抽条相关因素的分析,从中提取出4个主成分,由秋施基肥和不同果实成熟期代表的第1主成分反映了树体贮藏营养水平,是对抽条影响最大的因素,其次依次为树体细胞内的渗透势、霜霉病和树体当年有效营养生长时间。     

统计分析中主成分分析法与应用

在分析复杂社会经济现象和自然现象过程中,采用主成分分析法,将原始指标组合成新的相互独立的综合指标,利用线性函数理论和处理方法,求出主成分方程后再将原始指标进行标准化处理,求出综合评价值,而后对经济现象做出综合性评价分析。     

安徽农业可持续发展的主成分分析

构建评价安徽省农业可持续发展状况的指标体系应包括农业生产可持续发展、农业经济可持续发展、农村社会可持续发展和农业生态可持续发展等四个子系统。运用主成分分析方法综合评价安徽省2000—2008年农业可持续发展状况及其动态发展趋势,表明：2000年以来安徽省农业及其子系统发展状况良好,但仍然存在一些具体的不容忽视的问题。     

Principal component analysis using LISREL 8

The object of this article is to demonstrate that the widely disseminated program LISREL 8 can be used to carry out principal component analyses. LISREL 8 offers a number of useful possibilities including multigroup principal component analysis and principal component regression. Several illustrative analyses are reported.     

Principal component analysis using neural network

The authors present their analysis of the differential equation dX(t)/dt=AX(t)-XT(t)BX(t)X(t), where A is an unsymmetrical real matrix, B is a positive definite symmetric real matrix, X∈Rn; showing that the equation characterizes a class of continuous type full-feedback artificial neural network; We give the analytic expression of the solution; discuss its asymptotic behavior; and finally present the result showing that, in almost all cases, one and only one of following cases is true. 1. For any initial value X0∈Rn, the solution approximates asymptotically to zero vector. In this case, the real part of each eigenvalue of A is non-positive. 2. For any initial value X0 outside a proper subspace of Rn, the solution approximates asymptotically to a nontrivial constant vector (X0). In this case, the eigenvalue of A with maximal real part is the positive number λ=‖(X0)‖2B and (X0) is the corresponding eigenvector. 3. For any initial value X0 outside a proper subspace of Rn, the solution approximates asymptotically to a non-constant periodic function (X0,t). Then the eigenvalues of A with maximal real part is a pair of conjugate complex numbers which can be computed.     

NaCl胁迫对不同番茄品种幼苗及果实的影响

研究了NaCl胁迫对5个不同番茄品种的幼苗生长、果实可溶性糖含量及产量的影响.结果表明,盐胁迫抑制了番茄幼苗植株的生长,降低了幼苗的单株鲜重,减少了果实产量,但可以提高果实可溶性糖含量.同一盐胁迫条件下,不同番茄品种性状存在显著差异.     

主成分分析法及其EXCEL实现

主成分分析是一种重要的多元统计分析方法,其广泛应用于自然科学和社会科学的研究中。主成分分析运算过程较复杂,一般需要借助于统计软件来实现。如果手工运算不但计算量大,而且容易出错。文章利用EXCEL中的相关函数,给出了一种实现主成分分析的EXCEL简便算法。     

Principal component analysis: Most favourite tool in chemometrics

Principal component analysis (PCA) is the most commonly used chemometric technique. It is an unsupervised pattern recognition technique. PCA has found applications in chemistry, biology, medicine and economics. The present work attempts to understand how PCA work and how can we interpret its results.     

石榴皮中原花青素成分分析

采用正丁醇-盐酸法和硫酸-香草醛法等方法对开封产石榴的皮中原花青素进行了定性分析,结果表明其中含有原花青素,从而为综合利用丰富的石榴资源打下了良好基础。     

Principal component analysis and cluster analysis based orbit optimization for earth observation satellites

This paper proposes a design optimization method for the multi-objective orbit design of earth observation satellites, for which the optimality of orbit performance indices with different units, such as: total coverage time, the frequency of coverage, average time per coverage and maximum coverage gap, etc. is required simultaneously. By introducing index normalization method to convert performance indices into dimensionless variables within the range of [0, 1], a design optimization method based on the principal component analysis and cluster analysis is proposed, which consists of index normalization method, principal component analysis, multiple-level cluster analysis and weighted evaluation method. The results of orbit optimization for earth observation satellites show that the optimal orbit can be obtained by using the proposed method. The principal component analysis can reduce the total number of indices with a non-independent relationship to save computing time. Similarly, the multiple-level cluster analysis with parallel computing could save computing time.     

鞍山市规模以上工业企业经济效益的主成分分析

应用主成分分析方法对鞍山市规模以上工业企业经济效益进行分析,提取出三个主成分,并给出鞍山市各区、县的规模以上工业企业的综合实力得分排名.     

低品质黏土成分分析及处理工艺研究

为提升低品质黏土的纯度,对山东某企业提供的低品质黏土进行成分分析,在确定其主要杂质和呈色原因的基础上,提出了焙烧和磁选相结合的提纯脱色工艺,并利用XRF、XRD、SEM等方法对提纯后的黏土进行表征。结果表明:通过焙烧后磁选,黏土中Fe_2O_3、TiO_2质量分数分别减少1.38%和0.11%,达到陶瓷原料的要求,对提升黏土的品质具有显著的效果,为低品质黏土的提纯和脱色技术探索了一种行之有效的处理工艺。     

Genetic analysis of fruit shape traits at different maturation stages in sponge gourd

The fruit shape is important quantitative trait closely related to the fruit quality. However, the genetic model of fruit shapes has not been proposed. Therefore, in the present study, analysis of genetic effects for fruit shape traits （fruit length and fruit perimeter） in sponge gourd was conducted by employing a developmental genetic model including fruit direct effects and maternal effects. Analysis approaches of unconditional and conditional variances were applied to evaluate the genetic behavior of fruit shape traits at economical and physiological maturation times. The results of variance analysis indicated that fruit length and fruit perimeter were simultaneously affected by fruit direct genetic effects and maternal effects. Fruit direct genetic effects were relatively more important for fruit shape traits at whole developmental period. The gene expression was most active at the economical maturation stage （1-12 d after flowering） for two shape traits, and the activation of gene was mostly due to direct dominance effects at physiological maturation stage （13-60 datter flowering）. The coefficients due to different genetic effects, as well as the phenotypic correlation coefficients, varied significantly between fruit shape traits themselves at various maturation stages. The results showed that it was relatively easy to improve fruit shape traits for industrial purpose by carefully selecting the parents at economical maturation stage instead of that at physiological maturation stage.