共查询到20条相似文献，搜索用时 93 毫秒
1.
吴平 《宁波职业技术学院学报》2010,14(2):36-39
考虑一类偏微分方程特征值的上界估计,利用分部积分、Rayleigh定理和不等式估计等方法,获得了用前n个特征值来估计第n＋1个特征值的上界的不等式,其估计系数与区域的度量无关,这个结果在力学和物理学中有着广泛的应用。 相似文献
2.
吴平 《荆门职业技术学院学报》2010,25(2):35-39
考虑一类偏微分方程特征值的带权估计,利用分部积分、Rayleigh定理和不等式估计等方法,获得了用前n个特征值来估计第N＋1个特征值的上界的不等式,其估计系数与区域的度量无关,这个结果在力学和物理学中有着广泛的应用。 相似文献
3.
在线性回归模型Y=Xβ+ε;E(ε)=0;cov=σ2Σ;Σ>0下给出了有偏估计β*(K,d)=(XTΣ-1X+K)-1(XTΣ-1Y+dβ*),其中K>0,d>0为参数,β*表示线性回归模型的广义最小二乘估计,讨论了这种有偏估计的优良性质,得出了主要结论. 相似文献
4.
林路 《邵阳学院学报(社会科学版)》1995,(5)
本文通过后验对数似然函数,提出了若干有偏估计的后验Fisher信息比和后验似然距离统计量。这些统计量解决了模型扰动对有偏估计的影响度量问题。 相似文献
5.
提出了有随机约束的混合回归模型在椭球约束下的一类有偏估计,并给出了在均方误差矩阵和PC准则下此估计类优于一般线性模型在椭球约束下的有偏估计类的条件. 相似文献
6.
7.
在随机右删失情况下,证明了基于核光滑PL估计和PL分位点估计的Bahadur-Kiefer过程的横的弱极限定理。 相似文献
8.
余晗 《鹭江职业大学学报》1999,7(1):68-75
本主要讨论S-估计,这种S-估计具有偏度稳健性,且能达到误差敏感度下界,因而提供了尽量减小异常值影响的可能性。最后在给定误差敏感度γ*和溃崩点α下,寻找出最优统计判决法则。 相似文献
9.
对非齐次等式约束线性回归模型提出一种有偏估计,即条件岭型估计,证明了在一定的条件下,在均方误差及均方误差矩阵意义下都优于回归系数的约束最小二乘估计,并给出了两次随机数据模拟的结果,模拟数据结果表明在一定的条件下,条件岭型估计优于最小二乘估计. 相似文献
10.
在偏微分方程中,解的凸性的研究是一个有趣的问题,它反映了解的几何性质.Pinching-估计是一个重要的估计,也是研究解的凸性的一种重要方法,Pinching-估计主要来源于几何问题,把它在几何上的应用推广到半线性二阶椭圆偏微分方程,并且给出半线性二阶椭圆方程的Pinching-估计. 相似文献
11.
This study examined the accuracy of self‐ and other‐estimated intelligence in relation to tested cognitive ability and gender. Three groups of raters were examined: 187 (102 male, 85 female; mean age 14.33 years, SD = .32) pupils of single‐sex comprehensive schools, 109 (55 mothers and 54 fathers) parents, and six teachers of the pupils. Pupils estimated their own overall IQ, while their parents and teachers estimated the pupils’ overall, mathematical, spatial, and verbal abilities. Self‐ and other‐estimates were compared to each other, and to the child’s psychometric test scores in verbal, quantitative, and figural/non‐verbal reasoning ability. Results suggested that participants were reasonably accurate at estimating pupils’ intelligence – teachers significantly more so than parents, and pupils significantly more so than fathers. Although both parents significantly overestimated their child’s IQ, this overestimation was more pronounced in fathers. 相似文献
12.
对小麦旗叶衰老过程中的石蜡切片进行扫描电镜观察,结果表明,(1)旗叶衰老过程中,细胞核形态发生明显变化。即核呈球形,表面光滑,核孔匀称→核表面凸凹,部分核孔变大→核膜破裂,核解体,消失;(2)在籽粒成熟期小麦旗叶衰老及其细胞器退化消失明显加快;(3)细胞中叶绿体的退化、消失比线粒体稍快;(4)叶肉细胞的细胞核比维管束韧皮组织细胞核解体消失稍快。 相似文献
13.
This study investigated the relationship among sex, attitude toward intelligence, and self‐estimation of multiple intelligences for self and parents among Portuguese adolescents in secondary schools. Two hundred and forty‐two adolescents estimated their own and their parents' IQ scores on each of Gardner's 10 multiple intelligences: verbal (linguistic), logical (mathematical), spatial, musical, body‐kinesthetic, interpersonal, intrapersonal, existential, spiritual, and naturalistic. They also answered six simple questions concerning intelligence and intelligence tests. There were various sex differences in self‐estimated IQ: males rated themselves higher on overall, mathematical, spatial, intrapersonal, spiritual, and naturalistic IQ compared with females. Multiple regressions indicated that verbal, logical, and intrapersonal intelligence were significant predictors for self and parents overall IQ estimations. Factor analysis of the 10, the 8, and the 7 self‐estimates scores did not confirm Gardner's classification of multiple intelligences. Males were more likely to believe in sex differences in intelligence than females. Results are discussed in terms of the growing literature in the self‐estimates of intelligence, as well as limitations of that approach. 相似文献
14.
考虑六阶微分方程第二广义谱的含权上界估计,利用算子谱理论、分部积分、测试函数、广义Rayleigh定理和不等式估计等方法,获得了用第一个谱来估计第二个谱的上界的不等式,其估计系数与区间的几何度量无关,其结论是文献[1～3]的进一步推广. 相似文献
15.
The main purpose of the paper is to estimate the efficiency of a big public university in Italy using individual student-level data, modeling exogenous variables in human capital formation through a heteroscedastic stochastic frontier approach. Specifically, a production function for tertiary education has been estimated with emphasis on inefficiency and its determinants, taking explicitly into account the role played by students’ socio-economic and educational background. The empirical evidence, based on 48,338 freshmen, leads towards the use of individual-level data in order to control for the portion of the student academic achievement affected by the personal characteristics and effort, and the portion ascribable to the resources or organization of the institutional activities. Within the limit of external validity allowed by operating within only one university, efficiency scores derived from using both individual-level and aggregate level data do offer an important instrument to the university and governance structures. 相似文献
16.
研究了在语音传输过程中由于参数丢失导致语音质量急剧下降的丢帧补偿问题.利用大规模隐式马尔可夫模型对自适应多速率宽带语音编码(AMR-WB)的ISF参数进行建模,然后对丢失的ISF参数进行基于最小均方误差(MMSE)准则的最优估计,将估计的ISF参数和前帧的ISF参数进行加权以平滑估计值,得到补偿的ISF参数.在接收端,利用ISF参数的估计值进行语音合成.将本算法的合成语音和由G.722.2标准附件Ⅰ的基准补偿的合成语音进行比较,仿真结果表明,本补偿算法可以得到更好的性能,在频率加权谱失真和信噪比这2种评价准则上都有所改善,信噪比提高约2.41 dB,频率加权谱失真下降约0.885 dB,证明了该算法的有效性. 相似文献
17.
考察了在留曼边界条件下带有两捕食趋向和Holing-II型反应函数的三种群模型。应用抛物方程Shauder估计及Lp估计,证明了此模型存在唯一全局古典解。 相似文献
18.
郭春生 《廊坊师范学院学报》2003,19(1):81-85
俄罗斯与美国原本是冷战宿敌，俄美两国首脑互访改变了两国长期对抗的局面。通过首脑互访，两国在限制战略核武器，美国布置NMD，俄与美国、北约的战略、经济关系等问题上弥合了许多分歧，取得了广泛共识，俄罗斯终于以巨大的让步赢得在富民强国、重新回归欧洲道路上的重大进展。但是，俄罗斯与美国在许多重大问题上仍存在着分歧与矛盾，今后两国合作的道路决不会一帆风顺。 相似文献
19.
周晓燕 《山东商业职业技术学院学报》2012,12(1):15-17
随着一个国家社会生产力的发展,会计在日常经济生活中的作用将日益显著。作为会计知识的一部分,会计估计及会计估计的变更,在整个会计体系中的作用也就越来越重要了。如何正确使用会计估计、会计估计的变更,如何加强会计估计变更的审计便成为会计工作的重中之重。 相似文献
20.
An intensity-based non-rigid registration algorithm is discussed, which uses Gaussian smoothing to constrain the transformation to be smooth, and thus preserves the topology of images. In view of the insufficiency of the uniform Gaussian filtering of the deformation field, an automatic and accurate non-rigid image registration method based on B-splines approximation is proposed. The regularization strategy is adopted by using multi-level B-splines approximation to regularize the displacement fields in a coarse-to-fine manner. Moreover, it assigns the different weights to the estimated displacements according to their reliabilities. In this way, the level of regularity can be adapted locally. Experiments were performed on both synthetic and real medical images of brain, and the results show that the proposed method improves the registration accuracy and robustness. 相似文献