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991.
992.
图的谱矩序列与图的排序 总被引:1,自引:0,他引:1
图的谱矩是代数图论中一个重要的代数不变量,本文通过计算图的第5、6阶谱矩,研究了图的结构与图的谱矩之阃的联系,动态地研究了图的结构变化(包括图的阶数的增大及同阶前提下所含圈长度的变化等)对谱矩序列排列的影响,给出了研究图依谱矩序列排序问题的新方法. 相似文献
993.
Banach空间中p-严格渐近伪压缩映象的收敛性问题 总被引:7,自引:1,他引:7
在p-一致凸的Banach空间中(1
相似文献
994.
We treat some fractal and statistical features of the DNA sequences. First, a fractal record model of DNA sequence is proposed by mapping,DNA sequences to integer sequences, followed by the R/S analysis of the model and computation of the Hurst exponents. Second, we consider the transition between the four kinds of bases within DNA. The transition matrix analysis of DNA sequences shows that some measures of complexity based on transition proportion matrices are of interest. 相似文献
995.
996.
We show that the autocorrelation sequence of interarrival times for a Markovian arrival process (MAP) of order two is geometric. We determine the set of feasible values for the autocorrelation decay parameter and the first two or three moments of the interarrival time distribution. A method is derived for matching these parameters to a MAP of order two and some numerical examples are included to illustrate approximating higher dimensional MAPs by two dimensional ones. The numerical examples have helped us pose important questions regarding the significance of correlation in a MAP of order two when it is used as input to a queueing model. 相似文献
997.
本文证明了无穷矩阵算子代数(λ,μ)在左(右)强、K收敛意义下的乘积定理成立,给出了(λ,μ)在弱收敛意义下乘积定理成立的充要条件。 相似文献
998.
Complex modeling has received significant attention in recent years and is increasingly used to explain statistical phenomena with increasing and decreasing fluctuations, such as the similarity or difference of spike protein charge patterns of coronaviruses. Different from the existing covariance or correlation coefficient methods in traditional integer dimension construction, this study proposes a simplified novel fractional dimension derivation with the exact Excel tool algorithm. It involves the fractional center moment extension to covariance, which results in a complex covariance coefficient that is better than the Pearson correlation coefficient, in the sense that the nonlinearity relationship can be further depicted. The spike protein sequences of coronaviruses were obtained from the GenBank and GISAID databases, including the coronaviruses from pangolin, bat, canine, swine (three variants), feline, tiger, SARS-CoV-1, MERS, and SARS-CoV-2 (including the strains from Wuhan, Beijing, New York, German, and the UK variant B.1.1.7) which were used as the representative examples in this study. By examining the values above and below the average/mean based on the positive and negative charge patterns of the amino acid residues of the spike proteins from coronaviruses, the proposed algorithm provides deep insights into the nonlinear evolving trends of spike proteins for understanding the viral evolution and identifying the protein characteristics associated with viral fatality. The calculation results demonstrate that the complex covariance coefficient analyzed by this algorithm is capable of distinguishing the subtle nonlinear differences in the spike protein charge patterns with reference to Wuhan strain SARS-CoV-2, which the Pearson correlation coefficient may overlook. Our analysis reveals the unique convergent (positive correlative) to divergent (negative correlative) domain center positions of each virus. The convergent or conserved region may be critical to the viral stability or viability; while the divergent region is highly variable between coronaviruses, suggesting high frequency of mutations in this region. The analyses show that the conserved center region of SARS-CoV-1 spike protein is located at amino acid residues 900, but shifted to the amino acid residues 700 in MERS spike protein, and then to amino acid residues 600 in SARS-COV-2 spike protein, indicating the evolution of the coronaviruses. Interestingly, the conserved center region of the spike protein in SARS-COV-2 variant B.1.1.7 shifted back to amino acid residues 700, suggesting this variant is more virulent than the original SARS-COV-2 strain. Another important characteristic our study reveals is that the distance between the divergent mean and the maximal divergent point in each of the viruses (MERS > SARS-CoV-1 > SARS-CoV-2) is proportional to viral fatality rate. This algorithm may help to understand and analyze the evolving trends and critical characteristics of SARS-COV-2 variants, other coronaviral proteins and viruses. 相似文献
999.
This is a survey of results on joint universality in Voroninʼs sense of various zeta-functions, when in the collection of these functions some of them have the Euler product and the others have not. 相似文献
1000.
In this paper, we introduce the sequence space er(u,p) and investigate its some topological and geometrical properties such as basis, α-, β-, γ- duals and the uniform Opial property. 相似文献