系数域

This conclusion can also be proved by spectrum-warping audio watermarking algorithm in MCLT domain. To discuss further deeply on why spectrum-warping technique does not have the required robustness, the studies are carried out upon the essentials of bilinear transformation. All the theoretical analysis and experiments results put the robustness of the spectrum-warping audio watermarking under questioning.

四、提出了基于量化的变换域音频水印算法中关于量化参数的选择方法量化变换系数的音频水印算法是以修改谱分量幅值为基础，算法的主要问题是如何选择量化参数以确保算法的鲁棒性和不可感知性，另外量化系数的区域选择也会影响算法的性能。

The algorithm performs discrete cosine transform on sub image of host image, which is cover by visible watermarking, and compresses sub image by select the set of visually important DCT coefficients. Then, the algorithm hides the compressed sub image, which is encrypted by the hash function that is constructed by Rijndael code, in the high coefficient of wavelet domain.

算法将水印图像与宿主图像进行融合，并对隐藏子图采用DCT变换，按Zig_Zag排序保留视觉重要DCT系数的方法作压缩处理，并利用Rijndael密码构造单向Hash函数作加密处理，最终分散嵌入到宿主图像的带参数的整数小波域中的高频系数，实现了可见水印的有效嵌入。

The results show that the frequency characteristic corresponds with vortex structures; the detail and approximate characteristics of signal are reflected by wavelet coefficient at different scales; the coefficient map of continuous wavelet transformation reveals the self-similarity of the signal.

采用傅里叶变换和小波变换技术，实现了混合层密度脉动信号的频谱与多分辨率分析，结果表明：信号的频域特性与流场的涡结构相对应，不同层面的离散小波系数反映了不同尺度下信号与图像的细节和平滑近似特征，连续小波变换系数图定性的反映了信号的自相似特征。

Since the multiple scattering should be considered, the scattering problem of many-cylinders is more complicated than single cylinder. By using scattering matrix method to solve the scattering problem of many-cylinders, first we have to express the incident fieldand scattered field by special function（for example, Bessel function and Hankel function）under cylindrical coordinate, then use the addition theorem of special function to get a linear system of equations to relate the incident field coefficients and scattered field coefficients. The incident and scattered field coefficients for every cylinder can be solved from the linear equations by matching electromagnetic boundary condition pointwisely.

单颗圆柱散射体的散射场解析解很早就被解出，而多个圆柱阵列的散射场问题因为涉及到入射光在圆柱与圆柱间的多重散射，故散射行为较单颗圆柱的散射复杂，因此圆柱阵列的多重散射问题需要利用加法定理来处理；散射矩阵法的主要精神即是先用圆柱座标下的特殊函数对平面波和圆柱散射体的内外域电磁场做无穷级数展开，再藉由特殊函数的加法定理将所有圆柱散射体的展开中心移到同一个展开中心，最后可以得到一组连结整个散射系统的入射电磁场系数及散射电磁场系数的线性方程组，将该组线性方程配合电磁场在散射体边界的连续条件，便可分别求出圆柱阵列中各个圆柱体的内部电磁场与外部散射场，再利用线性叠加原理即可求得整个圆柱系统的全域电磁场分布。

The effect of tribology factors on bearing vibration is studied experimentally. AR model and WPT are used to processing the normal arid abnormal signals. The results are as follows:1. The vibration of ball bearings is caused by the tribology action of contact pairs of ball and ring races and has the essential of tribo-dynamics. Any factors affecting the tribology characteristics of contact pairs will affect vibration and noise of bearings consequently.2. Vibration characteristics of bearing keep almostly unchanged with the increasing of axial load expecting the increasing of nature frequencies. When radial load increasing with axial load unchanged, nature frequencies keep unchanged but some new vibration peaks appears in the spectrum.3. Vibration amplitudes are damped and nature frequency are enhanced with sufficient lubrication. Vibration and noise of bearings increase obviously and roar can happen and the contact surfaces scratch slightly under insufficient and unclean lubrication state. Bearing will be disabled in a few minutes without any lubrication.4. Bearing vibration is unstable under low speed. With the speed increasing, the vibration become stable and natural frequencies increase slightly but the amplitudes increase apparently.5. Bearing vibration can be excited only by some harmonics ofwaviness without lubrication and by all harmonics with lubrication based on the theoretical analysis.6. The nature frequencies of ball bearings decrease with the increasing sizes. When international clearance increasing, nature frequencies decrease in radial and increase in axial and angular and the amplitudes increase in radial and decrease in axial and angular. When the number of balls increasing, nature frequencies increase and amplitudes decrease. When the pitch diameter increasing, axial nature frequency increase and others nearly keep no change. When outer race groove curvature radius increasing, nature frequencies increase in radial and decrease in axial and angular and amplitudes keep no change in radial and increase in axial and angular. When inner race groove curvature radius increasing, nature frequencies decrease and amplitudes increase.7. The distortion in amplitude and frequency components of bearing vibration signals picked up by the present probe measurement method is founded and right conclusions cannot be achieved by the signals. When accelerometer is rigidly screwed with steel stud onto a flat outer surface of a ball bearing, vibration signal can be got without distortion and the reliability of research on bearing vibration is assured.8. AR model is suitable for large samples of bearing vibration signals, square root of length of samples can be used as the upper limitation of order determination and the FPE order selection criterion is effective. Many advantages of AR spectrum are founded over the classical based on FFT.9. Time-Frequency analysis is necessary for abnormal noise of ball bearings. WPT overcomes the principle shortcomings of STFT and proved to be a best tool to process the abnormal signals.

理论分析和试验研究表明： 1球轴承振动是钢球—滚道接触副中的各种摩擦学作用引起的，具有摩擦动力学的本质，任何对接触副的摩擦学特性有影响的因素都将对球轴承的振动和噪声特性产生影响； 2中心轴向载荷作用下，载荷增大使球轴承的固有振动频率升高，载荷越大同样的载荷增幅引起的频率升幅减小，足够大的中心轴向载荷作用下载荷的变化对球轴承振动的频率特性不会产生明显的影响； 3轴向和径向联合载荷作用下，径向载荷不大时球轴承振动的固有频率基本不变，但是可能引起变刚度激励的非线性振动，出现新的频峰，过大的径向载荷将使部分钢球脱离接触，使球轴承的振动和噪声呈现不稳定状态； 4润滑对球轴承的振动和噪声特性有重要的影响，良好的润滑对振动有明显的抑制作用，润滑不充分时，振动和噪声的水平会有明显增高，一定条件下还会激发接触副中的谐振，发出啸声，造成接触表面的伤害，无润滑干接触时，短时的运转就会损伤接触副表面，使振动和噪声迅速增大，并随时可能引发严重的磨损和卡滞失效；接触副润滑良好时，油膜的"刚化效应"使球轴承振动的固有频率有所提高，润滑剂中含有弥散性污浊时，振动的幅度总体升高，但弥散性污浊不会改变球轴承振动的频率特性；浙江大学博士学位论文：球轴承振动的研究 5低速时，球轴承振动的基本特征呈现不稳定状态，随着转速的提高，球轴承振动的频率特性趋于稳定，固有频率频峰升高； 6理论分析表明，干接触时钢球和滚道表面波纹度的某些谐波分量能激励球轴承的振动，振动的幅值与谐波幅值成正比，实际球轴承中钢球的分布不可能完全均匀，波纹度的激励作用会随时发生；润滑接触的分析表明，波纹度的任意谐波分量均能激励球轴承的振动； 7球轴承的几何和结构参数分析表明，球轴承尺寸越大，径向、轴向和角振动的固有频率越低；钢球中心圆直径增大，球轴承的径向和轴向振动的固有频率基本不变，角振动的固有频率有所上升，振动的幅频特性基本不变；径向游隙加大使球轴承的径向振动固有频率降低，轴向和角振动的固有频率有所升高，径向振动幅频特性的幅值升高，而轴向和角向降低；钢球的数量增多使球轴承振动的固有频率上升，幅频特性的幅值下降，径向振动的幅值下降最为明显；外圈沟曲率半径系数增大使球轴承径向振动的固有频率升高，轴向和角振动的固有频率降低，径向幅频特性基本不变，轴向和角向幅频特性幅值升高；内圈沟曲率半径系数增大使径向、轴向和角振动固有频率均下降，振动幅频特性的幅值均有升高； 8试验对比表明，传感器采用探针式安装时，由于探针接触副接触特性的影响，钡(量得到的球轴承振动信号有失真，采用专门设计和制作的试验球轴承，以固定式安装加速度计，首次测量得到了球轴承振动的真实信号，通过对振动信号的分析，验证了球轴承振动的理论模型； 9)基于时间序列分析的AR模型适用于大样本球轴承振动信号的分析，以样本长度的均方根值作定阶上界，FPE做判阶准则，给出的AR谱光滑，频率分辨率高，是球轴承振动分析的简便而可靠的手段； 10以时频域分析的小波包变换分析球轴承异音信号能够比较好地定位和聚焦异音发生的时间，时间间隔，频率范围，同样是球轴承振动分析的可靠的手段，可用作球轴承故障诊断技术。

The information Radon coefficient wrap-around of the line on a finite field was caused by the modular arithmetic so that the Radon coefficient information in the periodic oscillations direction was processed with discrete cosine transformation, and other direction information was processed with wavelet analysis in order to reduce the wrap-around of rebuilding information. At the same time, according to the characteristic of the noise, one kind of denoising threshold selection plan was proposed.

正交有限脊波分析处理信息时，有限域平面上的直线由于模运算的存在而引起信息Radon系数的卷绕，为此，对Radon系数周期振荡方向的信息采用离散余弦变换处理，其他方向信息采用小波分析处理，以减少卷绕对信息重建影响；同时，结合图像信息中噪声的特点，提出了一种去噪浮动阈值的选取方案。

In every period, do the following operations:# For each 8*8 block, do the discrete cosine transform, then take out direct current coefficient in each block, using the transformation above for each DC coefficient, the gold stands for the code of the spread-spectrum we use when embedding the different watermark bit in different frames, after all of the watermark information which we want to embed is embedded, then do the inverse discrete cosine transformation, and store the current frame in a new file.

于是利用DCT变换域的这点重要的几何不变性，我们可以推导出一种能够抵抗几何攻击的视频水印算法，即将所需要嵌入的水印信息以127位扩频序列作为辅助，以求和值形式嵌入到DCT变换后的每个宏块的每个DC系数当中，具体嵌入和提取算法如下：根据使用的扩频序列的长度N，基于相关的嵌入器需要选取包含N帧的视频子序列，令这N帧视频子序列作为一个嵌入周期，对于每N帧视频子序列做如下的操作，#即对于每个8×8的像素块进行DCT变换，然后取出每个DCT变换后的直流分量，对于每个DC系数，做如上所述的变换，其中gold为在第k帧中嵌入第i位水印信息时使用的扩频码字值，待将所有需要嵌入的水印信息全部嵌入后，再做反DCT变换，保存当前帧。

Thus we can assert that the difference between global and local squeezing parameter doesn't vanish is a sufficient criterion for the entanglement.

由这个关系，我们可以得到总体压缩系数与局域压缩系数的差值不为零可以作为子系统间存在纠缠的充分条件。

In this method,image compression is completed by singular value decomposition of the wavelet coefficient.

提出了基于小波域奇异值分解的图像压缩算法，该算法通过对小波分解系数进行奇异值分解，进而对小波系数进行压缩，实现图像压缩。

It indicates that simulation results by Z transform method are closer to analytical values than recursion convolution algorithm.

结果表明，Z变换算法的模拟结果比卷积分更接近理论值，标签时域有限差分 Z变换磁化等离子体反射系数透射系数 FDTD method Z transform Magnetized plasma Reflection coefficient Transmission coefficient

Singer Leona Lewis and former Led Zeppelin guitarist Jimmy Page emerged as the bus transformed into a grass-covered carnival float, and the pair combined for a rendition of "Whole Lotta Love".

歌手leona刘易斯和前率领的飞艇的吉他手吉米页出现巴士转化为基层所涵盖的嘉年华花车，和一双合并为一移交&整个lotta爱&。

This is Kate, and that's Erin.

这是凯特，那个是爱朗。