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81.
结合偏最小二乘法和支持向量机的优缺点,提出基于偏最小二乘支持向量机的天然气消费量预测模型。首先,利用偏最小二乘法确定影响天然气消费量的新综合变量,建立以新综合变量为输入,天然气消费量为输出的支持向量机模型,对天然气消费量进行了预测;然后,与多元回归、偏最小二乘回归、普通支持向量机做误差检验比较,验证该方法的可行性与正确性。结果表明,此天然气消费量预测模型具有较高的精确度和应用价值。 相似文献
82.
OnthePropertiesoftheSolutionofaStronglyDegenerateParabolicEquationChengFuxia(DepartmentofAppliedMathematics,TsinghuaUniversit... 相似文献
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84.
Trushar Gohil Robert H. P. McGregor Dominik Szczerba Kathrin Burckhardt Krishnamurthy Muralidhar Gábor Székely 《国际流体数值方法杂志》2011,66(8):1037-1067
Cardiovascular diseases are one of the major causes of long‐term morbidity and mortality in human beings. The nearly epidemic increase in prevalence of such diseases poses a serious threat to public health and calls for efficient methods of diagnosis and treatment. Non‐invasive diagnostic procedures such as MRI are often used in this context; however, these are limited in terms of spatial and temporal resolution and do not provide information on time‐dependent pressures and wall shear stresses—key quantities considered to be partially responsible for the formation and development of related pathologies. The present study is concerned with the numerical simulation of oscillatory flow through the abdominal aortic bifurcation. Computational fluid dynamics simulation of oscillatory flow in a branched geometry at high Reynolds numbers poses considerable challenges. The present study reports a detailed comparison of simulations performed with a finite volume and a finite element method, two approaches with significant differences in their discretization strategy, treatment of boundary conditions and other numerical aspects. Both solvers were parallelized, using loop parallelization of the BiCGStab linear solver for the finite volume and domain decomposition based on the Schur complement method for the finite element technique. The experience gained with these two approaches for the solution of flow in a bifurcation forms the focus of this study. Although similar results were obtained for both methods, the computation time required for convergence was found to be significantly smaller for the finite element approach. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
85.
Giuliano Alagona Caterina Ghio Alessandro Giolitti Susanna Monti 《Theoretical chemistry accounts》1999,101(1-3):143-150
Several histidine-tryptophan complexes (either stacked or T-shaped), derived from the crystal structures available in the
Brookhaven Protein Data Bank, have been examined with molecular mechanics (MM), using the Tripos force field with Gasteiger-Hückel
charges, whose trend was found to be analogous to the AMBER or CHARMM ones. The MM results were compared to the ab initio
MP2 results, with and without counterpoise (CP) correction, previously obtained using extended basis sets on 5-methylimidazole
and indole as model systems. MM seems to underestimate the interaction energy between the two monomers when compared to the
uncorrected MP2 results, while the agreement is much better after including the CP correction at the MP2 level in all cases.
MM was thus used to qualitatively analyse the dependence of the stacking energy on the ring rotation at a variable distance
and ring centroid displacement for these systems, while keeping the rings in parallel planes. An analogous study was carried
out for a T-shaped adduct.
Received: 24 March 1998 / Accepted: 3 September 1998 / Published online: 1 February 1999 相似文献
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The complete amino acid sequence of β-momorcharin, a ribosome-inactivating protein from the seeds of Momordica charantia Linn (Cucurbitaceae) has been determined. This has been done by the sequence analysis of peptides obtained by enzymatic digestion with trypsin, chymotrypsin and S. aureus V8 protease, as well as by chemical cleavage with BNPS-skatole. The protein consists of 249 amino acid residues containing one asparagine - linked sugar group attached to the site of Asn 5 1 and has a calculated relative molecular mass of 28,452 Da without addition of the carbohydrate. Comparison of this sequence with those of trichosanthin and other ribosome-inactivating proteins from different species of plants shows a significant homology with each other. Regarding the similarity of their biological properties, an active domain of these proteins has been predicted here. 相似文献
88.
通过分层立方网络HCNn (n≥3)的容错性分析,从理论上探讨了分层立方网络基于比较模型的条件诊断度,并证明其条件诊断度为tc(HCNn)=3n?2,大约是传统诊断度(t(HCNn)=n+1)的3倍. 相似文献
89.
The heat transfer analysis on the laminar flow of an incompressible third grade fluid through a porous flat channel is examined. The lower plate is assumed to be at a higher temperature than the upper plate. Analytical solution for temperature distribution is obtained for various values of the controlling parameters and discussed. The obtained analytical solution is also compared with the numerical solution. The comparison shows the fact that the accuracy is remarkable. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
90.
Guillermina Jasso 《The Journal of mathematical sociology》2013,37(2):109-136
It has long been thought that religious orders, by their very existence (apart from any direct service such as teaching or nursing), enhance the secular social welfare. This paper reports theoretical predictions, derived from the postulates of comparison theory, concerning the existence of this public benefit of the cloister and the determinants of its magnitude, including the effects of economic inequality and of the societal valued goods. The basic predictions suggest further implications for the rates of vocations and defections, for state sympathies toward religious orders, and for the rise and development of monastic and mendicant institutions. 相似文献