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131.
基于时间序列法的国税月度收入预测模型研究 总被引:2,自引:0,他引:2
研究了基于时间序列方法的国税月度收入预测. 通过采用Box-Jenkins的ARIMA模型, 结合国税月度收入数据, 分析并提出了一套针对月度税收收入的预测研究框架, 包括对税收预测模型的拟合、检验、预测、评价、动态修正等主要环节的处理方法. 在该研究框架的指导下, 以增值税、海关代征税和营业税为例, 对2006年各月的税收收入进行了模拟预测, 月度税收收入预测的平均相对误差分别控制在5.47\%, 8.63\%和2.37\%. 最后给出了在实际应用中动态修正税收预测模型的建议, 并简要讨论了时间序列方法在税收预测中面临的问题. 相似文献
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133.
Let A1,A2 be standard operator algebras on complex Banach spaces X1,X2, respectively. For k?2, let (i1,…,im) be a sequence with terms chosen from {1,…,k}, and define the generalized Jordan product
134.
Let and be standard operator algebras on infinite dimensional complex Banach spaces X and Y, respectively, and let Φ be a unital additive surjection from onto . We introduce thirteen parts of the spectrum for elements in and , and prove that if Φ preserves any one of these parts of the spectrum, then it is either an isomorphism or an anti-isomorphism. 相似文献
135.
Let be a maximal atomic nest on Hilbert space H and denote the associated nest algebra. We prove that a weakly continuous and
surjective linear map preserves the closure of numerical
range if and only if there exists a unitary operator such that for every or for every ,
where denotes the transpose of T relative to an arbitrary but fixed base
of H. As applications, we get the characterizations of the numerical range
or numerical radius preservers on . The surjective linear maps on the
diagonal algebras of atomic nest algebras preserving the closure of numerical
range or preserving the numerical range (radius) are also characterized.
Submitted: January 3, 2001?Revised: December 2, 2001 相似文献
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本文研究了无限维离散时间代数Riccati方程(DARE)的非负自伴解,给出了(DARE)有非负 自伴解的充要条件.对幂可稳定化的离散时间系统∑d(A,B,-),若A是可逆的,B是紧的,给出 了(DARE)的非负解集的参数化刻画,并以A的有限维的含于反稳定的不可观察子空间中的不变子 空间为参数.该结果把[5]中关于有限维系统∑d(A,B,-)的结果推广到了一般的系统∑d(A,B,-) 中.最后,还给出了∑d(A,B,-)具有非负稳定化解的充要条件. 相似文献
138.
Let be an infinite dimensional separable Hilbert space over the complex field. Structure characterizations are given for some elementary operators on which preserve point spectrum.
139.
The nucleotide excision repair system removes a wide variety of DNA lesions from the human genome, including photoproducts induced by ultraviolet (UV) wavelengths of sunlight. A defining feature of nucleotide excision repair is its dual incision mechanism, in which two nucleolytic incision events on the damaged strand of DNA at sites bracketing the lesion generate a damage‐containing DNA oligonucleotide and a single‐stranded DNA gap approximately 30 nucleotides in length. Although the early events of nucleotide excision repair, which include lesion recognition and the dual incisions, have been explored in detail and are reasonably well understood, the fate of the single‐stranded DNA gaps and excised oligonucleotide products of repair have not been as extensively examined. In this review, recent findings that address these less‐explored aspects of nucleotide excision repair are discussed and support the concept that postincision gap and excised oligonucleotide processing are critical steps in the cellular response to DNA damage induced by UV light and other environmental carcinogens. Defects in these latter stages of repair lead to cell death and other DNA damage signaling responses and may therefore contribute to a number of human disease states associated with exposure to UV wavelengths of sunlight, including skin cancer, aging and autoimmunity. 相似文献
140.