A new type of viscoelastic stochastic finite element method is established using first - order perturbation theory based on local averaging method of random field and karhunen - loeve expansion theory of random process . the amount of computations is greatly reduced by transforming correlated random variables to a set of uncorrelated random variables . the relations of different random response variables are analyzed and monte carlo simulations for viscoelastic stochastic structures are investigated 基于随机场的局部平均法以及随机过程的karhunen - loeve分解理论，通过一阶随机摄动方法建立了考虑材料近似不可压缩的粘弹性随机有限元公式，由相关结构分解减少计算量，分析了各结构随机响应量之间的关系，给出了数字特征的计算方法，研究了粘弹性随机结构的montecarlo模拟验证方法。
The fractal theory was used to study the character of liquid - vapor interface in the paper , hence the application of the fractal theory in thermal subjects could be solved and a way to calculate the fractional dimension number in the process of simulation could be put forward . the fractional dimension number describing the character of the liquid - vapor interface was calculated . the distinct fractional dimension numbers in x , y and z direction reveal that the simulation system is an anisotropic one 并将分形理论运用到汽液界面的研究中，提出了在汽液界面中计算分维数的方法，得到了描述汽液界面特性的数字特征变量? ?分维数，同时根据所得到的x 、 y和z方向分维数的不同，证明了汽液界面是各向异性的，并对汽液界面进行了定性和定量的分析，得到了汽液界面是典型的分形面的结论。
Based on the mathematical model for analyzing the seismic responses of submerged tunnels proposed by choshiro tamura and shunzo okamoto , the analytical model for calculating the stochastic earthquake responses of the whole underground structure was proposed and the formulas for evaluating the stochastic characteristics of the underground structural seismic responses were derived . the dynamical mean - square responses of the nanjing changjiang tunnel under gauss stationary random process were calculated . 3 2将日本田村重四郎?冈本舜三提出的沉埋隧道地震反应分析的数学模型应用于地下结构随机地震反应分析，利用数值分析方法建立了隧道整体随机地震反应分析的数学模型，得到了地下结构整体随机地震动力响应数字特征的数学表达式，为地下结构整体随机地震反应分析及动力可靠度的研究提供了一种分析途径。
But , though considerable process has been made in the last ten years , digital watermarking is still in its infancy , and much interesting work remains to be done this thesis addresses some problems in the gray - scale image digital watermarking that are summarized below : 1 ) whereas the basic theory of digital watermarking is still very poor , a digital watermarking mathematic model based on imperceptibility and robustness is presented by analysising the characteristic of digital watermarking ; 2 ) based on the model constructed above , by defining the measures of capacity and robustness of digital watermarking , an objective method for evaluating the digital watermarking is introduced and used to analysis some algorithms ; 3 ) whereas geometric distortion always influences the restoration of watermark , we advocate to enhance the robustness against geometric distortion by restoring the image which has been distorted by geometric transformation , and a method is designed for estimating the parameters of geometric transformation ; 4 ) based on the conclusion discussed above , and combined with the masking effects of hvs , a novel public meaningful gray - scale image digital watermarking is designed by analysising the characteristics of image gray - scale interpolation and haar wavelet transformation . the experimental results show that the method is indeed powerful ; 5 ) whereas many image digital watermarking schemes , which embed watermark by modifying the values of pixels in spatial domain and transformed domain , are confronted with the conflict between the imperceptibility and robustness , we advocated to use some stable digital characteristics of host image as watermark and a algorithm based on hermite matrix is designed 本文重点对灰度图象数字水印技术进行研究，主要工作如下： 1 )鉴于目前数字水印的理论研究比较薄弱的现状，本文通过分析数字水印的特点，建立了一个数字水印的数学模型，为进一步研究数字水印打下了基础； 2 )根据以上建立的模型，通过引入容量和稳健度的概念为数字水印提供了一个客观评价方法，并对一些数字水印算法进行了分析； 3 )为增强数字水印抵抗几何攻击的能力，研究了受几何攻击的图象的复原问题，并给出了一个计算图象几何变换参数的方法； 4 )通过分析图象灰度插值算法和haar小波变换的特点，结合hvs的掩蔽效应，设计了一个公开的有意义数字水印算法，实验结果表明本算法具有较强的稳健性； 5 )目前许多水印算法都是通过在空域或频域修改象素值的方法嵌入水印的，这种方法面临着透明性和稳健性的矛盾，为解决这个矛盾，本文提出以图象的某些稳定的数字特征为水印的观点，并结合hermite矩阵的特点设计了相应的水印算法，实验结果表明该算法具有较好的稳健性。
In the case of white noise , we research the system stochastic differential equation and fokker - planck ( fpk ) equation detailedly . the mechanism of sr is re - explained by system response speed and a new method is introduced , i . e . , psr theory and method . it is shown that the output signal - to - noise ratio ( snr ) obtained by adjusting systems parameters can exceed that by turning noise intensity , especially when the input noise intensity has already been beyond the resonance region or point 在白噪声假设下，以系统随机微分方程和其概率密度满足的fpk方程为基础，本文详细地探讨了非线性双稳态信号处理系统输出的数字特征，引入了系统响应速度，重新解释了随机共振现象产生的机理；通过系统参数调节，而不是调谐噪声来产生随机共振现象，提出了参数调节随机共振理论和方法。
The contents of this thesis include : 1 . by using the current aseismatic computation theory of the underground structures and the principles of impulse - response function , a method of acceleration impulse function applied in computing the seismic responses of the underground structures was proposed , the formulas for calculating the stochastic characteristics of the underground structural seismic responses were derived and an analytic method for this purpose was put forward 为此主要做了如下工作： 1将现有地下结构抗震计算原理和结构动力分析的脉冲响应函数原理结合起来，提出了地下结构地震动力响应计算的加速度脉冲函数法，推导了利用脉冲响应函数计算地下结构随机地震响应数字特征的数学表达式，提出了利用脉冲响应函数计算地下结构随机地震响应数字特征的分析方法。
Taken yanjia river watershed as an example , this study extracted watershed digital characters from dem , and simulated rainfall - runoff with the rainfall - runoff model based on gis and wms . the main contents and results include : ( 1 ) the building of the spatial database of watershed 本研究应用地理信息系统和wms模型系统，以三峡库区晏家河流域为例，由dem提取流域数字特征，再与降雨径流模型有机结合进行了降雨径流数字模拟研究，主要的研究内容和结果包括以下几个方面： ( 1 )建立了流域空间数据库。
The thesis discusses and analyses the sorting of wear , the way the wear particle formed and the characteristics of the wear particles . the thesis proposes that the method of tribology system analysis should be used in the research on the wear particle , the characteristics of wear particle have relation to the condition and process of wear , the characteristics of wear particle include the condition characteristics and construction characteristics of the tribology system 分析论述了磨损的分类以及相应磨粒的生成机理和磨粒的形态特征；提出了用摩擦学系统分析的观点研究磨粒分析，磨粒的形态与磨损状态、磨损机理有密切关系，系统磨粒的数字特征包括摩擦学系统的状态特征、结构特征。
Considering the randomness of physics parameters of structural material , geometric dimensions , damping , loads and closed loop control voltage respectively or simultaneously , the analytic model of the stochastic structure under random forces are built . the solving methods are proposed . the computational expressions of the numerical characteristic of the structural dynamic response are developed 2 、考虑压电智能桁架结构物理参数、几何参数、结构阻尼和外荷载、闭环系统控制电压分别或同时为随机变量，构建了结构在随机力作用下的动力响应分析模型，提出了求解方法，推导出结构动力响应随机变量的数字特征计算表达式，通过算例验证了所建模型和所提求解方法的正确性和有效性。
In the view of stochastic resonance ( sr ) and signal processing , parameter - turning sr ( psr ) theory and method is proposed and the characteristics of bistable systems are studied . the applications of psr in multi - frequency analog signal processing , digital baseband pulse - amplitude modulation signal transmission and digital carrier modulation signal transmission are investigated . this thesis has also introduced the concepts of parameter - adaptive sr and array - induced sr 本文主要从随机共振物理力学机理与信号处理的角度，研究了非线性双稳态系统的数字特征，提出了参数调节随机共振( psr )理论和方法，并将这一理论应用到多频模拟信号处理、数字基带信号传输和数字载波调制信号传输中，引入了参数自适应随机共振和阵列随机共振系统的概念。
