查询词典 fractal dimension

The features of the fractured medium and the rock matrix in the fractal composite reservoirs are describes with the fractal dimension (which describes the geometric features) and the fractal index (which depicts the connectivity of the fractal fluid flow network); An analysis mathematical model of well testing is proposed for inconstant flow rate with the closed outer boundary and the wellborn storage and the skin effects.

分形是研究自然和社会中广泛存在的零碎而复杂、无序、不规则、非线性、不光滑，具有自相似、自仿射和标度不变性的复杂系统、图形、构造、功能、性质和复杂现象，及隐藏在这些复杂现象背后的，具有精细结构、内在随机性，局部与整体本质联系的，被传统线性科学排斥在外的不规则"病态"，不可微的事体，形体。

The fractal theory was used to build fractal microfibril in wood cell wall,and fractal dimension of fractal microfibril layer S1 and layer S2 were calculates,then wood fiber frame with nanometer scale was pointed out.

利用分形理论构建了木材细胞壁中的分形木质纤维，并计算了分形木质纤维 S1层和S2层的扭曲分形维数，指出木材中具有纳米尺度的纤维结构；同时，以木材液化和纳米纺丝技术为基础，提出了木材苯酚液化产物制备碳素纤维材料的构思和技术路线，为解决木材纳米、微米材料的制备提出了新思路。

The experimental results have shown that the common logarithm values of transverse rupture strength lgσ〓 increase with the increase of fractal dimension D〓, and has a linear equation relationship. The microfracture fractal model of cermets has been founded and the estimated fractal dimension formula of fracture surfaces proposed.

建立了颗粒型复合材料金属陶瓷断裂的微观fractal模型，提出了计算断口表面分形维数的公式，指出断口分形维数依赖于测量码尺的选择，对金属陶瓷来说其临界测量码尺为0.07μm。

Through calculating the generalized dimension by covering the signal with n-dimension boxes, three dimension feature vectors including the box dimension, the information dimension and the correlation dimension are got.

首先利用覆盖法求取广义维数得到该语音信号的三维特征向量，包括容量维数、信息维数、关联维数；然后计算信号的维数特征距离；最后根据特征距离对语音信号类别进行决策分类。

In this research a new mathematical model - cubic polynom with two given derivatives at end points - was proposed which can good match the S-shpae curve.This model has a number of analytical features:describing the geographic phinomena prosesses in three hierarchies (textural fractal,structural fractal and state fractal); the boundary values of the structural fractal can be considered as the boundary values of interval of scaleless.

在研究中提出了扩展分维表达函数：带导数三次多项式，它能很好地表达反S形分布曲线，具有一系列解析特征：可从三个层次（纹理分形、结构分形和态势分形）上描述地理现象或过程；其中结构分形的边界可近似地看作是非扩展分维无标度区的上下界。

Experiments show that rhomb partitioning is more powerful in suppressing block artifacts than square partitioning, results in much higher reconstructed image quality, but takes longer encoding time; 2 For solving exhausting encoding problem of fractal image coding, we present a fast rhomb-partitioning fractal image coding based on neighbor-searching; we present a fast rhomb-partitioning fractal image coding based on block classification; we present a fast square-partitioning fractal image coding based on neighbor-searching, block classification and wavelet transform.

2针对分形图象压缩编码过程非常耗时的致命弱点，提出了基于邻域搜索的菱形块分割的快速分形图象压缩编码方法，提出了基于块分类的菱形块分割的快速分形图象压缩编码方法，提出了基于邻域搜索·块分类和小波变换的方块分割的快速分形图象压缩编码方法，实验结果表明，我们提出的快速分形图象压缩编码与传统的分形图象压缩编码相比，编码速度提高了近40倍。

Fractal is a subdiscipline of nonlinear area, researches on fractal characteristics of the deoxyribonucleic acid sequence may reveal some secret hidden in the DNA sequence during the process of biological evolution. Chaos Game Representation was proposed as a scale-independent representation for genomic sequences by Jeffrey in 1990. This technique, based on iteration function system, represents the word distribution statistics in DNA sequence as the fractal graphic. Therefore, we can get the distribution of sequence through analysis of fractal theory.

分形是非线性领域的一门分支学科，关于脱氧核糖核酸序列分形特征的研究，可以揭示生物在进化过程中隐藏在DNA序列中的某些秘密。1990年Jeffrey提出了基因组序列的与尺度无关的混沌游戏表示法，这是基于迭代函数系统的一种方法，它将DNA序列中一定长度字的分布规律表现为图形的分形特征，进而通过分形分析就可获取序列的分布规律，从而也成为DNA序列分析的一种统计方法。

Finally, fractal characteristic is researched in the thesis. Fractional Brownian motion characteristic of sea clutter is validated and fractal dimention of sea clutter without taget and sea clutter with target are calculated by box-dimention method.Target detection based on fractal dimention is analyzed in brief and sea clutter multi-fractal characteristic is analyzed by MF-DFA.

最后，本文对海杂波分形特性进行了研究，验证了海杂波符合分数布朗运动的特性，通过盒维数法计算纯海杂波和目标海杂波的分形维数，简要分析了基于单重分形维数的目标检测，并采用MF-DFA对海杂波多重分形特性进行了研究分析。

Taking landscape pattern fractal model and Landsat TM/ETM images in 1995 and 2000 as the basic data,the spatialtemporal database of land use in Chongqing City was established; and using fractal model of landscape pattern,fractal dimension and stability index of landscape pattern,landscape diversity index,landscape apartness index,landscape fragmentation index,landscape evenness index and landscape dominance index were obtained.

采用1995和2000年Landsat TM/ETM影像为基础数据，提取并建立土地利用空间数据库，应用景观空间格局分形模型，获取景观类型的分形维数和稳定性指数以及景观多样性指数、分离度指数、破碎度指数、均匀度指数和优势度等指标。

The results showed that during the research period,the fractal dimensions of paddy fields,dry land and wet areas increased obviously,whereas for forest land,shrubbery land and grass land,the fractal dimensions decreased.For all types of land,the values of landscape diversity index and landscape apartness index have increased but landscape dominance index value has rather decreased.Meanwhile it was found that the relation between fractal dimension and landscape fragmentation index showed significant positive correlation.

结果表明：水田、旱地、水域等土地类型的分形维数在研究时间段内有明显上升，有林地、灌木林地和草地等景观要素类型的分形维数降低；景观多样性和破碎度指数以及均匀度略有增加，而优势度指数下降；分形维数和破碎度指数呈极显著正相关。

The university spirits are the quintessence of a university, and they are cohesive force, creativity and vitality of a modern university.

大学精神是一所现代大学的凝聚力、创造力和生命力，是大学的精髓所在。

MODFLOW model is used to simulate ground water level and water quantity and forecast in this paper.

为了加强地下水资源的管理，合理开发利用和有效保护地下水资源，必须进行地下水资源的调查与评价。