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1.
Using the Wavelet as the Private Key for Encrypting the Watermark   总被引:1,自引:0,他引:1  
Watermarking is an effective approach to the copyright protection of digital media such as audio,image,and video.By inspriation from cryptography and considering the immensity of the set of all possible wvaelets,it is presented that in wavelet domain watermarking,the associated wavelet can be considered as the private key for encrypting the wavtermark so as to enhance the security of the embedded mark.This idea is partly supported by the fact that from computational complexity viewpoint.It is very time-consuming to search over the immense set of all candidate wavelets for the right one if no a priori knowledge is known about it .To verify our proposal,the standard image“Lena”is first watermarked in a specific wavelet domain,the watermark recovery experiments are then conducted in the wavelet domain for a set of wavelets with the one used for mark embedded in it ,separately.It follows from the experimetal results that the mark can be recovered only in the right wavelet domain,which jusstifies the suggestion.  相似文献   

2.
The effects of dietary supplementation with Clostridium butyricum on growth performance and humoral immune response in Miichthys miiuy were evaluated. One hundred and fifty Miichthys miiuy weighing approximately 200-260 g were divided into five groups and reared in 15 tanks with closed circuiting culture system. The animals were fed 5 diets: basal diet only (control) or supplemented of the basal diet with C. butyricum at doses of 10^3 (CB1), 10^5 (CB2), 10^7 (CB3) or 10^9 (CB4) CFU/g. Compared with the control, the serum phenoloxidase activity was significantly increased by the supplementation (P〈0.05), acid phosphatases activity was increased significantly (P〈0.05) at the doses of 10^9 CFU/g. Serum lysozyme activity peaked at dose of 10^7 CFU/g and in the skin mucus at dose of 10^9 CFU/g. Immunoglobulin M level in the serum and skin mucus was increased except at dose of 10^3 CFU/g (P〈0.05). The growth at the dose of 10^9 CFU/g was higher than that of the control (P〈0.05). It is concluded that supplementation of C. butyricum can mediate the humoral immune responses and improve the growth performance in Miichthys miiuy.  相似文献   

3.
We propose an adaptive fractional window increasing algorithm (AFW) to improve the performance of the fractional window increment (FEW) in (Nahm et al., 2005). AFW fully utilizes the bandwidth when the network is idle, and limits the operating window when the network is congested. We evaluate AFW and compare the total throughput of AFW with that of FeW in different scenarios over chain, grid, random topologies and with hybrid traffics. Extensive simulation through ns2 shows that AFW obtains 5% higher throughput than FeW, whose throughput is significantly higher than that of TCP-Newreno, with limited modi- fications.  相似文献   

4.
This paper presents the heating performance and energy distribution of a system with the combination of ground-source heat pump and solar collector or a solar-assisted ground-source heat pump system (SAGSHPS) by calculation and experiment.The results show that the average absolute error is less than 0.6 ℃ and the relative error is less than 5% under the pulse load when the analytical solution to the 2-D solid cylindrical source model is used for the SAGSHPS.The coefficient of performance (COP) of the SAGSHPS is 2.95-4.70.The average fluid temperature in the borehole heat exchanger can increase by 3 ℃ with the assistance of solar collector,which will improve the COP of the heat pump by approximately 10% from the experimental data.The energy contributions to the total heating load of soil,electricity and solar are 56.30%,36.87% and 6.83%,respectively.  相似文献   

5.
A new method of short-term forecasting for water consumption in municipal supply water networks based on wavelet transformation is introduced. By wavelet decomposing commonly used in the signal field, water consumption per hour is decomposed into many series. Trend item, cycle item and random item are separated from the original time series in this way. Then by analyzing, building a model, forecasting every series and composing the results, the forecasting value of the original consumption is received. Simulation results show that this forecasting method is faster and more accurate, of which the error is less than 2%, indicating that the wavelet analytical method is practicable.  相似文献   

6.
To enhance nominal current of high voltage vacuum circuit breakers (VCBs), a gravity heat pipe was proposed to replace stationary conducting rod of a high voltage vacuum interrupter. The heat pipe is composed of two coaxis tubes: the external tube is made of oxygen-free copper and the inner tube is made of stainless steel. The bottom end of the inner stainless steel tube is connected to the external copper tube by holes. Transient and static thermal performance of the heat pipe was measured, and the thermal resistance of it was compared with that of a solid copper rod with the same dimensions. Experimental results showed that thermal resistance of the heat pipe was about 1/3 of that of the copper rod, and it decreased slightly with the rising of the input heat flux. 3D thermal simulation on a 126 kV/2000 A single break VCB was done to compare the thermal performance between the proposed gravity heat pipe and the copper rod serving as the stationary conducting rod of the vacuum interrupter. Simulation results revealed that in the heat pipe case, the maximum temperature between contacts was 67 ℃ lower than that in the copper rod case.  相似文献   

7.
The secrecy performance of cooperation with an untrusted relay under a quasi-static fading channel is analyzed in this paper. An achievable secrecy rate is provided and the influence of selfish behavior of untrusted relay is analyzed. Furthermore, the secrecy performance of the scheme is discussed and compared with that of the case where the relay is just an eavesdropper. Simulation results show that the untrusted relay’s cooperation in the fading case reduces the outage probability from 1/2 to 1/3 and achieves a higher outage secrecy capacity.  相似文献   

8.
Study of the effect of dissolved oxygen and shear stress on rifamycin B fermentation with A. mediterranei XC 9-25 showed that rifamycin B fermentation with Amycolatoposis mediterranei XC 9-25 needs high dissolved oxygen and is not very sensitive to shearing stress. The scale-up of rifamycin B fermentation with A mediterranei XC 9-25 from a shaking flask to a 15 L fermentor was realized by controlling the dissolved oxygen to above 25% of saturation in the fermentation process, and the potency of rifamycin B fermentation in the 15 L fermentor reached 10 g/L after 6-day batch fermentation. By continuously feeding glucose and ammonia in the fermentation process, the potency of rifamycin B fermentaion in the 15 L fermentor reached 18.67 g/L, which was 86.65% higher than that of batch fermentation. Based on the scale-up principle of constantly aerated agitation power per unit volume, the scale-up of rifamycin B fed-batch fermentation with continuous feed from a 15 L fermentor to a 7 m3 fermentor and further to  相似文献   

9.
In this paper, a plug-in hybrid electrical vehicle (PHEV) is taken as the research object, and its dynamic performance and economic performance are taken as the research goals. Battery charge-sustaining (CS) period is divided into power mode and economy mode. Energy management strategy designing methods of power mode and economy mode are proposed. Maximum velocity, acceleration performance and fuel consumption are simulated during the CS period in the AVL CRUISE simulation environment. The simulation results indicate that the maximum velocity and acceleration time of the power mode are better than those in the economy mode. Fuel consumption of the economy mode is better than that in the power mode. Fuel consumption of PHEV during the CS period is further improved by using the methods proposed in this paper, and this is meaningful for research and development of PHEV.  相似文献   

10.
In this paper, more efficient, low-complexity and reliable region of interest (ROI) image codec for compressing smooth low texture remote sensing images is proposed. We explore the efficiency of the modified ROI codec with respect to the selected set of convenient wavelet filters, which is a novel method. Such ROI coding experiment analysis representing low bit rate lossy to high quality lossless reconstruction with timing analysis is useful for improving remote sensing ground truth sur- veillance efficiency in terms of time and quality. The subjective [i.e. fair, five observer (HVS) evaluations using enhanced 3D picture view Hyper memory display technology] and the objective results revealed that for faster ground truth ROI coding applications, the Symlet-4 adaptation performs better than Biorthogonal 4.4 and Biorthogonal 6.8. However, the discrete Meyer wavelet adaptation is the best solution for delayed ROI image reconstructions.  相似文献   

11.
利用转移算子和一致可积性的有关知识,讨论了周期小波分析中高维周期尺度函数的双正交性,得到了尺度函双正交的充要条件,所得结果推广了尺度函数正交性的某些结果,在周期小波分析理论及应用的研究中,具有重要意义。  相似文献   

12.
采用非线性滤波方法处理图像去噪问题时,阈值参数的选取和恰当使用滤波器函数,对去噪图像的效果影响极大。文章构造了可用于非线性滤波算法的一族分段次小波阈值参数滤波器函数,它是Donoho的软阈值滤波器函数的推广,证明了滤波后的逼近是Besov空间中泛函的近似最小值。该滤波器函数次数越大,逼近效果越好,也证明了广义软阈值滤波器函数的极限是一理想低通滤波器。仿真结果证实了区间双正交小波比Daubech ies小波有更好的去噪效果。  相似文献   

13.
以构造双正交小波的Cohen-Daubechies-Feauveau定理为基础,利用提升方法构造了一组对称双正交9.7小波滤波器.它与JPEG2000中采用的CDF9-7小波压缩性能几乎相同,并且它们两者在图像压缩中可以互相作正变换与逆变换.新9-7小波的计算只需要2个浮点运算和16个整数运算,而CDF97小波需要14个浮点运算,因而它能极大简化和减少图像压缩和视频压缩的运算量.  相似文献   

14.
INTRODUCTION The inverse kinematics problem (IKP) for a ro- botic manipulator involves obtaining the required manipulator joint values for a given desired end-point position and orientation. It is usually complex due to lack of a unique solution and closed-form direct ex- pression for the inverse kinematics mapping. The forward kinematics problem (FKP) is to find the po- sition and orientation of the end-effector based on given joint values which can be easily obtained by analyzing the …  相似文献   

15.
提出了利用Legendre小波解第二类非线性Fredholm积分方程的小波Galerkin近似方法.积分方程的非线性部分由在区间[a,b]上构造的Legendre小波进行逼近,而且将非线性积分方程化简为非线性积分方程组.给出的例子说明了此逼近方法的有效性和可操作性.  相似文献   

16.
该文研究了基于小波变换的暂态电能质量扰动的检测算法,利用快速小波变换算法即Mallat算法检测和提取扰动信号,并在MATLAB环境下进行了仿真,采用db4小波、3尺度进行小波分解与重构并对信号进行检测,验证了小波变换能够实现电能质量扰动信号的准确定位。  相似文献   

17.
利用滤波器,研究了在高密度离散小波变换下消失距的框架函数;由多带小波与多小波的设计启示,推导出小波的应用与算法的关系,并进一步研究在不同消失距个数作用下的紧框架.  相似文献   

18.
探讨应用Wavelet-Galerkin方法求解一维波动方程的初边值问题,通过修改边界上的小波函数,得到满足齐次边界条件的有限区域的小波基,用Wavelet-Galerkin方法离散微分方程后,得到一个确定小波系数的线性方程组,此方程组的系数矩阵在一维情况下是一个带状矩阵,且其中还有许多小的元素,其逆矩阵有类似的性质.数值实验表明,小波为求解微分方程提供了一个新的强有力的工具,用它来求解方程得到的小波近似解能很好地满足各种边界条件,且解的精度可以通过增加小波函数或增加尺度而得到提高.  相似文献   

19.
为了改善信号的去噪效果,在分析离散小波变换和双密度小波变换的基础上,提出一种基于双密度小波变换的去噪算法。双密度小波有两个小波函数,同一个尺度内相邻的小波间的频带间隔更小,有效的克服了离散小波变换时移性的缺点,有近似的平移不变性,更能描述信号的真实特征。将该算法用于不同噪声强度下的信号去噪,实验结果表明:基于双密度小波变换的去噪算法优于基于离散小波变换的去噪算法,是一种有效的信号去噪新算法。  相似文献   

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