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81.
函数的Tchebycheff—Fourier级数的(N,P)平均逼近 总被引:2,自引:0,他引:2
徐延安 《绍兴文理学院学报》1997,(6)
讨论了算子(N,P)的最佳逼近阶以及达到此逼近阶的一个充分条件。得到了f∈Lipα及f’∈Lipα时逼近误差的上界。 相似文献
82.
周世力 《江汉大学学报(人文科学版)》1996,(3)
本文基于反义寡核苷酸技术的基本原理,评述了该技术的主要内容和近些年来的研究进展;着重介绍了其在农业、医药和生物学基础研究等方面的应用.此外,还分析了此技术在应用方面存在的一些问题,并展示了其应用前景. 相似文献
83.
A sorting-and-measuring machine (SMM) measures and sorts (classifies) on-line produced items into several groups according to their size. The measuring devices of the SMM perceive the actual item size with a random error ε and classify the item as being smaller than b iff z+ε<b. Here ε is a normal zero-mean r.v. with unknown standard deviation σ which is the main parameter characterizing the precision and technical condition of an SMM. The paper gives the following method of estimating σ. N0 items are measured and N1 of them are recognized by the SMM as belonging to the group a<z≤b. These N1 items are sorted again and N2 of them return to this group, these are sorted again, and so on. The estimation of σ is based on the statistics Nm/Nn. Moments of the ratio statistics Nm/Nn and their distributional properties are investigated. It turns out that the expected value of Nm/Nn depends almost linearly on σ which allows us to construct ‘almost’ unbiased estimators of type with good propert including robustness with respect to the distribution of item size. Convex combinations of statistics are considered to obtain an estimator with minimal variance. 相似文献
84.
This analysis examined causal links in China’s defence–growth nexus in 1960–2016. The results show that better growth significantly reduces military-civilian ratio and propels military reforms. The unidirectional threshold causality from growth to defence shows that the military impact on a positive change in China’s growth is little in the long term. Conversely, the growth impact of a positive change in defence has accelerated after it reaches the threshold year in 1987. This finding explains why Chinese economy stagnated when defence was prioritised and why China has risen dramatically in the Far East after three decades of fast economic growth. 相似文献
85.
We develop a model of the interactions among decentralization, informal institutions and the rule of law. The model sheds light on the ambiguous empirical results reported in the literature regarding the growth effects of the policy of devolving fiscal responsibility to local governments. We find that the distribution of civicness within a country determines the magnitude of the effects of decentralization on its regional convergence, as well as whether decentralization fosters or dampens the country’s national growth. We perform a series of simulated “reforms” using Monte Carlo methods parameterized using OECD countries data set. We then test our findings using a panel data set of 23 OECD countries covering the period 1975–2010. We find that the short and the long run growth effect of decentralization policy depends on the size of the policy reform and can range from extremely negative to positive depending on the rule of law, the level of social capital and its regional dispersion, in line with the model predictions. 相似文献
86.
For doubly truncated data, i.e. the variables of interest are only observable if they lie in a certain random interval, an additive hazard model with time-dependent regression coefficients is investigated. Consistency and asymptotic normality are proven under mild assumptions. A simulation study investigates the finite sample properties and the influence of the truncation distribution on the estimation error. Finally, the method is applied to a doubly truncated data set of German companies, where the age at insolvency is of interest. 相似文献
87.
In this article, we consider the efficient estimation of the semiparametric transformation model with doubly truncated data. We propose a two-step approach for obtaining the pseudo maximum likelihood estimators (PMLE) of regression parameters. In the first step, the truncation time distribution is estimated by the nonparametric maximum likelihood estimator (Shen, 2010a) when the distribution function of the truncation time is unspecified or by the conditional maximum likelihood estimator (Bilker and Wang, 1996) when is parameterized. In the second step, using the pseudo complete-data likelihood function with the estimated distribution of truncation time, we propose expectation–maximization algorithms for obtaining the PMLE. We establish the consistency of the PMLE. The simulation study indicates that the PMLE performs well in finite samples. The proposed method is illustrated using an AIDS data set. 相似文献
88.
Declining employment success of immigrant males in Sweden: Observed or unobserved characteristics? 总被引:1,自引:0,他引:1
Focusing on Nordic and Yugoslavian immigrant males, we study the determinants of employment success of natives and immigrants
in Sweden. Furthermore, we investigate the reasons behind the arising gap in employment success between Swedes and immigrants
from 1970 to 1990. In a decomposition analysis, we find that the main part of the decline in the employment probability of
immigrants relative to Swedes over time is explained by a change in coefficients (unobserved characteristics) rather than
a change in determinants (observed characteristics).
Received: 22 June 1998/Accepted: 23 March 2000 相似文献
89.
瞿建慧 《吉首大学学报(社会科学版)》2008,29(1):141-144
湖南境内湘语“V+X+N(L)”的结构形式共有四种:“V+在+N(L)”、“V+到+N(L)”,“V+体貌助词+N(L)”和“V+体貌助词+在+N(L)”。“V+体貌助词+在+N(L)”的来源于六朝时期就已常见的“(S-P)在NL”结构。 相似文献
90.
调查分析了绵阳市郊区 (石马、龙门、塘汛 )蕃茄、黄瓜、菜豆 3种蔬菜的平衡施肥状况。结果发现其施肥养分比 (N∶P2 O5∶K2 O)分别为 1∶0 .6 2∶0 .6 0、1∶0 .53∶0 .57、1∶0 .52∶0 .6 0 ,与其吸肥特性相比 ,施氮相对较多 ,施钾明显偏低 ,氮钾比失调。因此 ,推荐施肥方案要求控制氮肥 ,保证磷肥 ,增加钾肥用量 ,使施肥的N∶P2 O5∶K2 O分别应达到 1∶0 .6 2∶1.10 (蕃茄 ) ,1∶0 .55∶1.2 0 (黄瓜 ) ,1∶0 .50∶1.15(菜豆 )。 相似文献