应用逐步统计判别模型预报麦蚜复合种群动态

本文应用逐步统计判别原理 ,对山东省曲阜地区 1982～ 1994年共 13年麦蚜复合种群动态的系统调查资料进行了统计分析 ,建立了 4个统计判别数学模型 :dy1=0 .1 343x1- 0 .1 472x2 ;　　y2 =0 .740 9x1- 0 .1 1 85x2 ;y3=- 8.391 5x1- 1 .785 6x2 ;　y4=2 .32 40x1- 0 .30 82x2运用所建模型 ,对历史资料进行回代验证 ,其平均历史拟合率在 93%以上 ,并以 1 995年作为独立样本进行试报 ,结果与实际一致。     

2003年全国攻读硕士学位研究生入学考试数学试题(一)(附答案)

一、填空题 (本题共 6小题 ,每小题 4分 ,满分 2 4分 )( 1 )　 limx→ 0 ( cosx) 1ln( 1+ x2 )　　 =　 1e　。( 2 )　曲面 z=x2 +y2 与平面 2 x+4 y-z=0平行的切平面的方程是　 2 x+4 y-z=5　。( 3 )　设 x2 =∑∞n=0ancosnx( -π≤ x≤π) ,则 a2 =　 1　( 4)　从 R2 的基 α1=10 ,α2 =　 1-1 到基 β1=11 ,β2 =12 的过渡矩阵为 　 2　　　 3-1　　 -2 　。( 5)　设二维随机变量 ( X,Y)的概率密度为f ( x,y) =6x,　　 0≤ x≤ y≤ 1 ,0 ,　　　其他则 P{ X+Y≤ 1 } =　 14 　。( 6)　已知一批零件的长度 X(单位 :cm)服从正态分布 N(…     

应用统计分辨原理预报害虫种群动态

本文应用基于Fisher准则下统计分辨原理，对山东省曲阜市1982～1994年棉花苗期棉蚜的系统观测资料进行了数量分析，建立了统计分辨数学模型：y＝－0．2359x1－0.0049x2，经对历史资料的回报验证，其历史拟合率为92．31％．将1995年观测数据作为独立样本进行试报，其预报结果与实际一致．     

丢番图方程X~2-(a~2+1)Y~4=3-4a

设a≥2是正整数.本文证明了:当a=2时,方程X~2一(a~2+1)Y~4=3-4a仅有正整数解(X,Y)=(20,3);当a=3时,该方程仅有2组互素的正整数解(X,Y)=(1,1)和(79,5);当a≥4且4a+1非平方数时,该方程最多有4组互素的正整数解(X,Y);当a≥4且4a+1为平方数时,该方程最多有5组互素的正整数解(X,Y).     

关于丢番图方程X~2-(a~2+1)Y~4=8-6a

设a是正整数.本文证明了:当a=1时,方程X~2-(a~2+1)Y~4=8~6a仅有正整数解(X,Y)=(2,1);当a=2时,该方程仅有正整数解(X,Y)=(1,1);当a=3时,该方程无正整数解(X,Y);当a=4时,该方程仅有2组互素的正整数解(X,Y)=(1,1)和(103,5);当a≥5且6a+1非平方数时,该方程最多有3组互素的正整数解(X,Y);当a≥5且6a+1为平方数时,该方程最多有4组互素的正整数解(X,Y).     

非参数回归函数的基于截尾数据的估计

本文考虑截尾数据情况下非参数回归函数m(x)=E(Y|x)的估计。具体地讲,我们面对的是这样的数学模型:T是与(X,Y)独立的随机变量,我们观测到的不是Y本身,而是Z=min(Y,T)及δ=[Y≤T]。今有训练样本{(X_i,Z_i,δ_i)}_(i-1)及当前样本(X,z,δ),记ξ_i(·)=[z_i≥·], N~ (·)=sum from i=1 to n ξ_i(·), V_n(·)=multiply from i=1 to n{1 N~ (z_i)/2 N~ (z_i)}~[δ_i=_i<0], U_n(·)=sum from i=1 to n Wnt(x)ξ_i(·), 令 m_n(x)=integral from 0 to u_n U_n(y)|V_n(y)dy, 其中u_n=F_2~(-1)(n~(-a)),0<α<1/2为一实常数,F_2(·)=P(Y≥·)为Y的(右侧)分布函数。在权函数{W_(ni)(x)}_(i=1)~n及(X,Y,T)的分布函数满足一组条件下,我们证明了m_n(x)为m(x)的强相合估计,即:m_n(x)→m(x),a.s.(n→ ∞).     

线性回归模型Liu估计的新研究

考虑线性回归模型Y=Xβ+ε,E()ε=0,Cov()ε=2σI(1),当设计矩阵X的列存在共线性时,最小二乘估计^β=(X′X)-1X′Y的性质变坏,为此给出了有偏估计^(βK,d)=(X′X+K)-1(X′Y+d^β),其中K为对角矩阵,K=diag(k1,…kp),ki≥0,d>0为参数,讨论了这种有偏估计与广义岭估计、Liu估计的比较,并证明了其可容许性估计.     

关于丢番图方程X~2+4Y~4=pZ~4

设p为素数,p=4A~2+1+2|A,A∈N~*.运用二次和四次丢番图方程的结果证明了方程G:X~2+4Y~4=pZ~4,gcd(X,Y,Z)=1,除开正整数解(X,Y,Z)=(1,A,1)外,当A≡1(mod4)时,至多还有正整数解(X,Y,Z)满足X=|p(a~2-b~2)~2-4(A(a~2-b~2)±ab)~2|,Y~2=A(a~2-b~2)~2±2ab(a~2-b~2)-4a~2b~2A,Z=a~2+b~2;当A≡3(mod4)时,至多还有正整数解(X,Y,Z)满足X=|4a~2b~2A-(4abA±(a~2-b~2))~2|,Y~2=4a~2b~2A±2ab(a~2-b~2)-A(a~2-b~2)~2,Z=a~2+b~2.这里a,b∈N~*并且ab,gcd(a,b)=1,2|(a+b).同时具体给出了p=5时方程G的全部正整数解.     

高中数学综合练习题(二)

一、选择题: 1.若实数x满足log_3x≤1-coso,则|x-1| |x-9|的值是( )。 (A)-8;(B)8;(C)与o有关;(D)以上答案都不对。 2.若x∈R,则(1-|X|)(1 x)是正数的充要条件是( )。 (A)|x|<1;(B)x<1;(C)x<-1;(D)X<-1或-1相似文献   

线性模型中一些无偏损失估计的不可容许性和可容许性

设 Y～N_n(Xβ,σ~2V),此处 X 和 V 分别是已知的 n×P 和 n×n 矩阵,rank(X)=p≤n,V>0(即 V 是正定的),β∈R~P 是参数向量,σ>0已知或未知.记(?)=(X′V~(-1)X)~(-1)X′V~(-1)Y,S~2=Y′[V~(-1)-V~(-1)X(X′V~(-1)X)~(-1)X′V~(-1)]Y.对于σ已知情形,本文证明了,在均方误差损失[α-((?)-β)′((?)-β)]~2之下,损失((?)-β)′((?)-β)的无偏估计σ~2tr(X′V~(-1)X)~(-1)在 P≤4时是可容许的,而当P≥5时不可容许.对于σ也是未知参数且 P相似文献   

判别分析在小儿支原体肺炎早期诊断中的应用

本文对辽宁中医学院附属医院儿科收治的 90例肺炎病例进行了判别分析 ,求得判别函数 ,并应用于临床 ,收到了较为满意的效果。     

Identifying distress among banks prior to a major crisis using non-oriented super-SBM

We illustrate how data envelopment analysis (DEA) can be used as a forward-looking method to flag bank holding companies (BHCs) likely to become distressed. Various financial performance models are tested in the period leading up to the recent global financial crisis. Results generally support DEA’s discriminatory and predictive power, suggesting that it can identify distressed banks up to 2 years in advance. Robustness tests reveal that DEA has a stable efficient frontier and its discriminatory and predictive powers prevail even after data perturbations. DEA can be used as a preliminary off-site screening tool by regulators, by business managers to ascertain their standing among competitors, and by investors. Attention by regulators can be further directed at potentially distressed banks as some of them would be candidates for closer monitoring. In conclusion, DEA may be useful in making economic decisions because there is an identifiable link between inefficiency and financial distress. To the best of our knowledge, application of DEA to predict financial distress among BHCs prior to a major crisis has not been published.     

判别分析法对增发股投资价值的分析及预测

本文通过增发股相关指标数据的特别处理 ,对增发股投资价值进行了判别分析 ,求得了判别函数 ,并应用于增发股的投资预测     

Comparing the Spanish and the discriminatory auction formats: A discrete model with private information

The Spanish Treasury is the only Treasury in the world that uses a hybrid system of discriminatory and uniform price auctions to sell government debt: winning bidders pay their bid price for each unit if this is lower than the weighted average price of winning bids (WAP), and pay the WAP otherwise. Following Gordy [Gordy, M., 1996. Multiple bids in a multiple-unit common-value auction. Board of Governors of the Federal Reserve System], we model the Spanish auction as a common value auction of multiple units with private information, allowing for multiple bids. Numerical analysis shows that bidders spread their bids more in the Spanish than in the discriminatory auction and bid higher for the first unit, and that the expected seller’s revenue is higher in the Spanish than in the discriminatory auction within a reasonable set of parameter values.     

Distributive solutions for absolutely stable games

Every absolutely stable game has von Neumann-Morgenstern stable set solutions. (Simple games and [n, n?1]-games are included in the class of absolutely stable games.) The character of these solutions suggests that the distributive aspect of purely discriminatory solutions is of as much conceptual importance as the discriminatory aspect.     

Discriminatory power and pure strategy Nash equilibrium in the lottery Blotto game

This paper highlights the role of discriminatory power in showing the existence of pure strategy Nash equilibrium in a two-player lottery Blotto game. Precisely, when the discriminatory power of the contest success function in every battle is less than or equal to one, a pure strategy Nash equilibrium always exists for any prizes and budgets. However, we construct examples in which pure strategy Nash equilibrium fails to exist as long as the discriminatory power of only one battle exceeds one.     

基于Lasso+SVM的制造业上市公司财务风险组合预警模型

根据组合预测思想构建了基于Lasso+SVM的制造业上市公司财务风险组合预警模型,包括串联型组合和信息融合型组合两种,并选取22个财务指标建立了财务预警指标体系,对我国86家制造业上市公司的财务状况进行了预测,还与单一风险预警模型预测效果进行了比较,结果发现:财务风险组合预警模型的预测效果明显高于单一预警模型,用第t-1年的财务数据进行预测的准确率达到了95%以上;串联型组合预警模型的预测效果最优,用第t-1和t-2年的财务数据进行预测的准确率分别达到了100%和90%.     

Elastic and Thermophysical Properties of Poly(Vinyl Chloride) and Chlorinated Polyethylene Blends

The results of experimental and theoretical investigations of elastic and thermophysical properties of poly(vinyl chloride) (PVC) and chlorinated polyethylene (CPE) blends are presented. Eight types of specimens with different ratios of weight contents of PVC and CPE (PVC/CPE = 100/0, 90/10, 80/20, 60/40, 40/60, 20/80, 10/90, and 0/100) were tested. The effect of blend composition on the elastic constants (tensile and shear modulus) is discussed. The data on the thermal conductivity, thermal diffusivity, and heat capacity of the blends investigated are also presented.     

关于非退化的二阶曲线的分类研究

从抛物线的一种判定方法出发,借助于欧氏平面上非退化的二阶曲线的度量性质,通过对欧氏平面上非退化二阶曲线类型的研究,探究出确定非退化二阶曲线类型的若干定理。