通过分析树型多重分形结构的相关性发现,多重分形可以把非平稳且具有长相关(LRD)和分形特性的网络流量序列转化为可用短相关(SRD)模型表示的序列组。利用多重分形这种将时间序列分解为多层的能力,提出了一种结合多重分形的FIR神经网络...通过分析树型多重分形结构的相关性发现,多重分形可以把非平稳且具有长相关(LRD)和分形特性的网络流量序列转化为可用短相关(SRD)模型表示的序列组。利用多重分形这种将时间序列分解为多层的能力,提出了一种结合多重分形的FIR神经网络流量预测模型(MF-FIR,multifractal FIR network)。MF-FIR合理地利用了流量序列的LRD信息,具有很好的多步预测性能,可以满足通信系统在线预测的要求。展开更多
Soil particle size distribution(PSD),one of the most important soil physical attributes,is of great importance to soil water movement,soil erosion and soil solute migration.In this study,the soil PSD of 563 soil sampl...Soil particle size distribution(PSD),one of the most important soil physical attributes,is of great importance to soil water movement,soil erosion and soil solute migration.In this study,the soil PSD of 563 soil samples from the mulched drip irrigated cotton fields in Xinjiang of China were measured by laser diffraction particle size analyzer.The soil PSD characteristics and its relations with soil water and salt were studied by using the combined methods of textural triangle,fractal and multifractal analysis.The results showed very low clay content(about 1.52%) while really high sand content of the studied soil,and a complex shape of bimodal or unimodal of soil PSD.The results also showed that the two indices,i.e.,standard deviation and the peak value of soil particle relative volumes,were good indicators of soil PSD and thus had good relations with fractal and multifractal characteristics.The correlative analysis further indicated that the mulched drip irrigation had a significant impact on the distribution of the soil salt,while this impact withered for the deeper soil layer.The soil texture feature was found to dominate soil water and salt distribution,especially the surface soil salt content and the deep soil water content.展开更多
文摘通过分析树型多重分形结构的相关性发现,多重分形可以把非平稳且具有长相关(LRD)和分形特性的网络流量序列转化为可用短相关(SRD)模型表示的序列组。利用多重分形这种将时间序列分解为多层的能力,提出了一种结合多重分形的FIR神经网络流量预测模型(MF-FIR,multifractal FIR network)。MF-FIR合理地利用了流量序列的LRD信息,具有很好的多步预测性能,可以满足通信系统在线预测的要求。
基金supported by the National Key Technology R & D Program of China (Grant No 2007BAD38B01)the National Science Founda-tion for Post-doctoral Scientists of China (Grant No 20100470297)
文摘Soil particle size distribution(PSD),one of the most important soil physical attributes,is of great importance to soil water movement,soil erosion and soil solute migration.In this study,the soil PSD of 563 soil samples from the mulched drip irrigated cotton fields in Xinjiang of China were measured by laser diffraction particle size analyzer.The soil PSD characteristics and its relations with soil water and salt were studied by using the combined methods of textural triangle,fractal and multifractal analysis.The results showed very low clay content(about 1.52%) while really high sand content of the studied soil,and a complex shape of bimodal or unimodal of soil PSD.The results also showed that the two indices,i.e.,standard deviation and the peak value of soil particle relative volumes,were good indicators of soil PSD and thus had good relations with fractal and multifractal characteristics.The correlative analysis further indicated that the mulched drip irrigation had a significant impact on the distribution of the soil salt,while this impact withered for the deeper soil layer.The soil texture feature was found to dominate soil water and salt distribution,especially the surface soil salt content and the deep soil water content.
