On algebraic approximations of certain algebraic numbers

Using hypergeometric functions and the Thue-Siegel method we give an effective improvement of Liouville's approximation theorem. As an application, we derive effective upper bounds for the solutions (X,Y) of the two-parametric family of quartic Thue inequalities

|BX4−AX3Y−6BX2Y2+AXY3+BY4|?N     

基于彩色扫描仪的图像光谱重构

针对彩色扫描仪的特点,采用主元分析法(PCA)和反向传播(BP)人工神经网络(ANN)相结合的方法对图像光谱重构进行研究。选择IT8.7/2标准色卡作为训练样本,将该色卡中的另一组色靶作为检验样本以讨论不同网络结构以及不同主元数和训练样本数对光谱重构的影响,再以自然色系统(NCS)色卡为检验样本来分析不同种类的训练和检验样本与光谱重构性能的关系。实验结果表明,采用3-14-6网络结构和6个主元数是最佳选择,训练样本和扫描目标之间的一致性是基于彩色扫描仪图像光谱重构的关键所在。     

建立模糊诊断矩阵的一种新方法

本文首先提出了一个新的模糊逻辑算子——模糊加权综合算子“#”,进而给出建立模糊诊断矩阵的新方法——网络法 ,并给出了相应的算法     

GA-BP嵌套算法的理论及应用

分析了BP算法、遗传算法以及GA-BP-APARTING算法的特点,提出了GA-BP-NESTING算法.在人工神经网络的在线学习和离线学习方式下,分别对BP算法、GA算法、GA-BP-APARTING算法和GA-BP-NESTING算法进行了比较研究,研究发现:第一,网络初始权值的赋值对人工神经网络训练影响很大;第二,离线学习方式下GA-BP-NESTING算法效果最佳.     

V-fold交叉验证和BP神经网络在信用评价中的应用

研究关于公司神经网络信用评估问题的现状，提出一套甄选方法准则。用于建立适合于我国企业的信用评分指标体系；然后依据该指标体系建立了基于BP回归神经网络的信用评估模型；采用V—fold交叉验证技术，利用样本公司实际指标数据对该模型的评分效果进行了实证研究。     

期货价格预测——反向传播神经网络模型

利用神经网络的 BP算法 ,对较难解决的期货价格问题做了一些研究 ,获得了一定的成功 .     

Mathematical modelling of selected characterisation procedures for oil fractions

Models of two important characterisation procedures for oil and oil fractions, ASTM D86 (ASTM = American Society for Testing of Materials) and EFV (Equilibrium Flash Vaporization), were presented. The purpose was to provide a basis for the construction of substitute mixtures of real components used in modelling and simulation of chemical engineering processes instead of original complex mixtures. It was shown how to deal with a possible problem of higher index of differential-algebraic model of the ASTM D86. A number of examples proved the adequacy of the presented models. Presented at the 34th International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 21–25 May 2007.     

Enzyme-mediated biodegradation of heat treated commercial polyethylene by Staphylococcal species

Extruded low-density polyethylene (LDPE) films commonly available in the market as 20-micron thick carrier bags were autoclaved, overlaid on nutrient agar plates and inoculated with BP/SU1 strain of Staphylococcus epidermis. The nutrient agar plate showed growth of the organism within two to three days. The polymer film supporting the growth of the organism showed pore formation as recorded by SEM analysis. The growth of BP/SU1 is supported by the presence of shredded LDPE as its only carbon source in inorganic salt minimal nutrient medium. The organism survives even after three months of inoculation and this is accompanied by gradual breakdown of the size of the shredded plastic as seen by light scattering. The cell-free supernatant of the organism, grown with the help of shredded plastic shows the presence of the over expressed proteins with approximate molecular weight of about 55 kDa and 35 kDa, through SDS-PAGE analysis.     

Dispersive blow-up for nonlinear Schrödinger equations revisited

The possibility of finite-time, dispersive blow-up for nonlinear equations of Schrödinger type is revisited. This mathematical phenomena is one of the conceivable explanations for oceanic and optical rogue waves. In dimension one, the fact that dispersive blow up does occur for nonlinear Schrödinger equations already appears in [9]. In the present work, the existing results are extended in several ways. In one direction, the theory is broadened to include the Davey–Stewartson and Gross–Pitaevskii equations. In another, dispersive blow up is shown to obtain for nonlinear Schrödinger equations in spatial dimensions larger than one and for more general power-law nonlinearities. As a by-product of our analysis, a sharp global smoothing estimate for the integral term appearing in Duhamel's formula is obtained.     

一种维修性神经网络模型

运用神经网络的ＢＰ算法建立了系统的维修性模型，结合一实例验证了模型，效果较好。