期刊文献+
共找到6篇文章
< 1 >
每页显示 20 50 100
低温雨雪冰冻灾害性天气对中国养蜂业影响的因素分析 被引量:1
1
作者 李海燕 崔尧 +2 位作者 刁青云 刘世丽 吴杰 《中国农学通报》 CSCD 北大核心 2009年第11期1-6,共6页
通过利用《中国蜂业》杂志社在2008年第3期《中国蜂业》中发放《2008年1—2月全国养蜂业雪灾损失调查表》所反馈的信息,与各省蜂业管理部门及蜂业合作组织的调查资料汇总,借助社会统计学工具,通过相关分析、多因素独立样本总体分布检验... 通过利用《中国蜂业》杂志社在2008年第3期《中国蜂业》中发放《2008年1—2月全国养蜂业雪灾损失调查表》所反馈的信息,与各省蜂业管理部门及蜂业合作组织的调查资料汇总,借助社会统计学工具,通过相关分析、多因素独立样本总体分布检验、Asymptotic双尾显著性检验等计量和统计学方法,科学的分析在低温雨雪冰冻天气下各种因素对中国养蜂业的影响,并深入探讨各种因素与养蜂业抵御低温雨雪冰冻灾害性天气能力之间的关系。得出了转地能力强的养蜂户在抵御低温雨雪冰冻灾害性天气的能力上强于转地能力差的定地养蜂户;经验丰富的专业养蜂户和经验相对差的业余养蜂户并没有明显的差别;中蜂在总体上抗逆性明显强于饲养西蜂;科学饲养蜜蜂的养蜂户明显强于传统饲养蜜蜂的养蜂户的结论,并且提出加大对蜂业基础性科学研究的经费投入;提高"大转地"养蜂户的比例;大力培养蜂业科技人员等建议来减少低温雨雪冰冻灾害性天气对中国养蜂业造成的损失。 展开更多
关键词 低温雨雪冰冻灾害性天气 养蜂业 随机变量普通相关分析 多因素独立样本总体分布检验 Asymptotic双尾显著性检验
下载PDF
Metrics on Noncompact Fuzzy Number Space E^n
2
作者 冯玉瑚 《Journal of Donghua University(English Edition)》 EI CAS 2004年第2期83-87,共5页
The theory of metric spaces of fuzzy numbers has been established and found very convenient in many research fields on fuzzy analysis such as fuzzy integrals and differentials, fuzzy differential equations, fuzzy rand... The theory of metric spaces of fuzzy numbers has been established and found very convenient in many research fields on fuzzy analysis such as fuzzy integrals and differentials, fuzzy differential equations, fuzzy random variables and fuzzy stochastic processes etc.. But, a large part of this theory heavily depends on the condition that fuzzy number has to have compact support set and so fails to analyze and apply noncompact fuzzy numbers. The purpose of this paper is to introduce three classes of metrics on noncompact fuzzy number space and to discuss their basic properties, completeness and separability in detail. 展开更多
关键词 Noncompact fuzzy number METRIC COMPLETENESS SEPARABILITY ANALYSIS
下载PDF
Some Practical Issues Related to Univariate Regression Analysis Prior to Multivariate Regression Analysis in Randomized Controlled Clinical Trials
3
作者 A.K. Mathai B.N. Murthy 《Journal of Mathematics and System Science》 2013年第8期371-380,共10页
Often many variables have to be analyzed for their importance in terms of significant contribution and predictability in medical research. One of the possible analytical tools may be the Multiple Linear Regression Ana... Often many variables have to be analyzed for their importance in terms of significant contribution and predictability in medical research. One of the possible analytical tools may be the Multiple Linear Regression Analysis. However, research papers usually report both univariate and multivariate regression analyses of the data. The biostatistician sometimes faces practical difficulties while selecting the independent variables for logical inclusion in the multivariate analysis. The selection criteria for inclusion of a variable in the multivariate regression is that the variable at the univariate level should have a regression coefficient with p 〈 0.20. However, there is a chance that an independent variable with p 〉 0.20 at univariate regression may become significant in the multivariate regression analysis and vice versa, provided the above criteria is not strictly adhered to. We undertook both univariate and multivariate linear regression analyses on data from two multi-centric clinical trials. We recommend that there is no need to restrict the p value of 〈= 0.20. Because of high speed computer and availability of statistical software, the desired results could be achieved by considering all relevant independent variables in multivariate regression analysis. 展开更多
关键词 Univariate regression multivariate regression clinical trial.
下载PDF
铝合金在不同应力状态下微损伤演化的声发射研究 被引量:3
4
作者 李建宇 贾中汇 张扬扬 《实验力学》 CSCD 北大核心 2020年第4期650-658,共9页
利用声发射技术对不同应力状态下铝合金的微损伤演化规律进行试验研究。首先,对铝合金在正断和切断两种断面取向的试样进行单轴拉伸试验,并同时采集微损伤声发射信号;其次,基于所采集的微损伤声发射信号构建了一个能够表征微损伤能量尺... 利用声发射技术对不同应力状态下铝合金的微损伤演化规律进行试验研究。首先,对铝合金在正断和切断两种断面取向的试样进行单轴拉伸试验,并同时采集微损伤声发射信号;其次,基于所采集的微损伤声发射信号构建了一个能够表征微损伤能量尺度特征和时间序列特征的随机损伤变量,进而通过对该随机变量的分析来研究铝合金在不同应力状态下的微损伤演化特征;最后,通过计算随机损伤变量在不同外载荷水平下的概率熵给出描述材料微损伤演化过程的一种表征。通过试验并辅以对断面的扫描电镜观测获得的结果是,同一种铝合金材料在两种不同应力状态下获得的微损伤概率熵曲线具有显著差异性,而在相同应力状态下分别针对铝合金材料1060和6063的微损伤概率熵曲线又具有一致性。上述研究结果可为探索铝合金在不同应力状态下的微损伤演化规律提供参考。 展开更多
关键词 铝合金 微损伤 声发射 随机变量分析 概率熵
原文传递
Interval design point method for calculating the reliability of structural systems 被引量:2
5
作者 NI Zao QIU ZhiPing 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2013年第11期2151-2161,共11页
The evaluation of reliability for structural system is important in engineering practices.In this paper,by combining the design point method,JC method,interval analysis theory,and increment load method,we propose a ne... The evaluation of reliability for structural system is important in engineering practices.In this paper,by combining the design point method,JC method,interval analysis theory,and increment load method,we propose a new interval design point method for the reliability of structural systems in which the distribution parameters of random variables are described as interval variables.The proposed method may provide exact probabilistic interval reliability of structures whose random variables can have either a normal or abnormal distribution form.At last,we show the feasibility of the proposed approach through a typical example. 展开更多
关键词 PROBABILITY design point method interval analysis probabilistic interval reliability parameters UNCERTAINTY
原文传递
Convergence rate of kernel canonical correlation analysis 被引量:5
6
作者 CAI Jia SUN HongWei 《Science China Mathematics》 SCIE 2011年第10期2161-2170,共10页
Kernel canonical correlation analysis(CCA) is a nonlinear extension of CCA,which aims at extract-ing the information shared by two random variables. It has wide applications in many fields,such as information retrieva... Kernel canonical correlation analysis(CCA) is a nonlinear extension of CCA,which aims at extract-ing the information shared by two random variables. It has wide applications in many fields,such as information retrieval. This paper gives the convergence rate analysis of kernel CCA under some approximation conditions and some suggestions on how to choose the regularization parameter. The result shows that the convergence rate only depends on two parameters:the rate of regularization parameter and the decay rate of eigenvalues of compact operator VY X,and it gives better understanding of kernel CCA. 展开更多
关键词 covariance operator canonical correlation analysis RKHS
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部