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The methods of image compression could be summed up as the lossy and loseless compression.

图像压缩的方法很多，但一般可分为有损压缩和无损压缩两大类。

Comparing with lossy image compression, the lossless image compression is more difficult and itsdevelopment is slower.

图像的无损压缩相对有损压缩来说更加困难，取得的进展也更小。

Lossy compression on the other hand allows some loss, but has the potential for much higher compression rates.

损失性图像压缩则允许某些图像信息丢失，但在压缩比上有着更大的潜力。

The main work and innovation1 In general , a image compression method has different effect to different image . Some are fit for image which has much high frequency . Some are fit for image which has much low frequency .This paper analysis the applicability of fractal algorithm . In this dissertation , an improved algorithum is given . The basic algorithum without eight change and the joint use of quantitative coding , The compression ratio and PSNR can be adjusted , and it can get more quickly speed of coding .2 To a group of exact fractal code , the decoding image can be any resolution .With this characteristic ,choose the proper domain block and range block,this paper get an algorithum which can get higher decoding PSNR and speed than the basic fractal algorithum.3 Give a new method to calculate the scale factor . The calculation of basic algorithum is complex and enormous . The factor of scale is an important variable of the basic algorithm. Now there are two methods to calculate the factor of scale .A new method was given to calculate the factor of scale. The calculation load and complexity are reduced by the new method. Compared with the basic algorithm , the method can reduce coding time.4 The basic fractal algorithum is based on the Collage theorem and contraction mapping theorem . A mathematic model based on basic fractal algorithum is given .

本文的主要工作及创新点主要包括以下几点：1一般情况下，一种图像压缩的方法对不同特点的图像，压缩效果会有所不同，本文利用分形压缩编码对不同特点的图像进行编码，分析了分形编码对不同图像的编码适用性，利用去掉8种变换的分形编码算法与简单的均匀量化编码方案相结合，得到了一种可以调节压缩比与解码质量的分形编码方案，该提高编码速度6倍以上。2分形编码的特点之一是分形解码的分辨率无关性，即对于一组分形编码可以将其解码到任意分辨率下，本文利用分形编码的这一特点，结合不同的量化编码方案，选择合适的定义域块与值域块及适当的编解码分辨率，得到了一种提高解码质量，编码速度提高12倍以上的加速算法。3比例因子是基本分形算法中的一个重要变量，目前有两种计算比例因子的方法，文中给出了一种新的求比例因子的方法，该方法简化了求比例因子的计算，从整体上减小了基本分形算法的计算量，简化了算法4分形压缩的数学基础是不动点定理与拼贴定理，本文根据基本的自动分形编码方法，建立数学模型对其进行推导，得到了用普通数学的极限理论解释分形编码的数学表达式，从而对由基本分形编码得到的解码图像中的像素点的值给出了确定的表达式。

In the wet compression process the evaporation model of water droplets was established. Based on mentioned above multi elemental section constant pressure mathematical models for actual wet compression processes was established.

且在了解湿压缩过程中的液滴蒸发速率、蒸发时间等基本理论的基础上建立了湿压缩过程的等压微元段的实际湿压缩的数学模型。

In this thesis, The way of mergence of the two methods is discussed based on the analysis of wavelet image compression and fractal image compression.

本文在分析分形图像压缩与小波图像压缩的基础上，对二者相结合的途径和方法进行了探讨。

The procedure is based on the concept that the critical load of a frame without sidesway is the same as the smallest value among these critical loads of the compression members of the frame with partially restrained ends, and the critical load of every compression member may be determined by the method of successive approximation.

将组成刚架的各桿件视为两端受不同约束的桿件，用静力学的方法求出此等桿件相应的临界荷重，其中最小值即为刚架的临界荷重，举有实例以示演算程序。

The numerical results showed that multi-stage compression could be an efficient approach to achieve high compression rate.

这些数值结果表明，多级压缩是一种提高脉冲压缩比的有效方法。

Establish the steady-state and transient model using the three hydrodynamics equations (Continuity equation, Momentum equation and Energy equation). By comparing different state equation, it selects the BWRS state equation which is considered the most accurate state equation in current natural gas measurement. It calculates compression factor, density and other Thermal parameters based on BWRS state equation. In Numerical solution of the steady-state and transient model, compression factor, friction coefficient and all the other Thermal parameters are recalculated in each small time step to reduce the numerical calculation error.

在稳态模型的建立上，利用流体力学三大方程(连续性方程、运动方程和能量方程)，通过比较不同的状态方程选用了目前被认为最精确的用于天然气计量的BWRS状态方程，并以此方程为基础进行压缩因子、密度等热物性参数的计算；在稳态模型的求解上，选用容易计算，精度较高的标准型龙格—库塔(Runge-Kutta)法进行数值求解，并且在迭代过程的每一小步都重新计算燃气的压缩因子，摩阻系数等所有的计算参数，以减少数值计算的误差。

Usually translation of failure mode is ignored, which should result in much more serious conclusions. The main aim of this paper is to present the importance of nonsymmetry corrosion. Components under geometric center compression and large eccentric compression are taken as examples for bridge pier and column structure reliability analysis.

由钢筋锈蚀而造成的桥梁结构损伤已成为世界普遍关注的问题，在混凝土劣化机理、钢筋锈蚀机理、钢筋锈蚀量的预测以及锈蚀后钢筋性能变化等方面都进行了大量的研究并取得了卓越的成就，现役钢筋混凝土结构的可靠性鉴定及剩余寿命预测就是在这些成果的基础上进行的[1～5]。

But GST= 0.156, Nm=1. 588. As a result, the foundation of Youyongchi Avicennia marina population was the result of the migration of hypocotyles and human factors.

这项工作可以为海岸防护林中新引进种类的判定以及为研究种群建立者效应方法的确定提供科学依据。

The two-dimensional CDRC-ADI-FDTD update equations for collision unmagnetized plasma are induced. The unconditional stability of the CDRC-ADI-FDTD formulation for collision unmagnetized plasma is obtained by the examples.

推导了碰撞非磁化等离子体中的二维CDRC-ADI-FDTD迭代公式，并用算例验证了碰撞非磁化等离子体CDRC-ADI-FDTD算法也是无条件稳定的。