Abstract:The copyright protection of digital multimedia has become an impending issue.The effective pirate validation of the digital multimedia is the precondition for effective copyright protection. In this paper,an improved algorithm in discrete wavelet transfor

Abstract:提出了一种新的多比特水印算法。该算法把基于图像自身的水印信息嵌入到图像的DC系数中,通过视觉模型控制DC系数的改变程度,在保证水印不可见性的同时,提高了水印的鲁棒性。为实现水印的盲检测,采用Gold码序列对水印信息进行了扩频。在检测阶段,充分利用Gold序列良好的相关性恢复出水印。应用所提出算法,把水印信息嵌入到一幅512×512的灰度图像中。实验表明,该算法对常规信号处理攻击和几何攻击具有很强的鲁棒性。

Abstract:A segmentation algorithm based on the technique of one-dimension maximal variance between-class and region growing method is proposed in this paper.Firstly,the method of one-dimension maximal variance between-class is used to obtain the optimal segmenting

Abstract:Watermarking algorithm has become a primary method in copyright issue and content authentication of digital multimedia.A watermarking algorithm based on the wavelet transform is discussed in this paper.Numeric simulation indicates that this algorithm can

Abstract:Embedded Linux Firewall System has a character of limited resource,of which communication with the outside is an important aspect.In this paper,the usage of serial port and parallel port in the instance of limited resource is introduced. The programming m

Abstract:基于惯性制导工具误差模型,推导出存在工具误差时的再入点运动参数模型。并以加速度表误差为例,通过仿真计算得到不同精度的加速度表对再入点运动参数的影响。由于再入点运动参数准确与否直接影响到导弹引爆的控制精度,本文的研究成果可为以后进一步研究提高导弹引爆的控制精度奠定基础。

Abstract:Because of the complication of projectile structure,research object and penetration process,the hard target penetration process is not stationary.The data from the projectile penetrating target experiment comprise plenty of frequency signals.Wavelet trans

Abstract:In self-encoded spread spectrum (SESS) communication system,the spreading codes are generated based on the random data stream and are time-varying random codes.Based on the traditional SESS system,a new method is presented to produce the SESS codes with t

Abstract:The influence of the outliers on the Kalman filter is analyzed.A method based on M-estimate dealing with outliers is proposed.The method has the immunity to not only single outlier but also a mass of outliers.Simulation test has validated this method.

Abstract:DC-voltage comparative method and high sampling digital multimeter method can measure the pulse amplitude accurately,but their application is relatively limited.They are applied to the periodice low frequency pulse signals only.By adopting general electro

Abstract:介绍了模拟数字转换器静态和动态参数测试技术以及实现测试的硬件平台及软件环境,采用斜波或纯正弦信号作为输入信号,用数字集成电路测试系统控制采样,并将模拟数字转换后的数据存储,利用测试系统内的软件将存储数据进行变换,来获得模拟数字转换器的静态参数和动态参数测试结果。该测试方法具有可编程的优点,是非常适用的测试方法。

Abstract:A method of measuring airborne velocity using Doppler technology with width beam radar signal is presented.It realizes the aim of using one radar altimeter to measure velocity and height both.Time domain and frequency domain hybrid algorithm is used to pr

Abstract:A self-adaptive ultra-wideband frequency-agile pulse doppler (PD) fuze for air-face missile is introduced in this paper. It remarkably improves the anti-active-jamming ability by combining the mature design of the pseudorandom code PM PD fuze and the self

Abstract:对鉴相频率泄漏进行抑制,又不破坏环路的稳定性,是工程设计中必须重视的问题。本文通过对几种常用锁相环环路滤波器电路模型的传递函数的计算和分析,获得了在不破坏锁相环路稳定性的前提下对鉴相泄漏良好抑制的电路模型和参数。同时,分析表明:当锁相环的鉴相频率很低时,鉴相泄漏的抑制尤为重要,采用二阶低通有源滤波器具有最好的抑制性能。

Abstract:One novel microwave bandpass filter is introduced in this paper.This filter,which is easy to be implemented physically,has the skirt selectivity intermediate between Chebyshev filters and the elliptic-function filters. The transfer function of the filter

Abstract:为了满足在脉冲γ辐射测量中对测量动态范围大、对中子相对不灵敏、而对γ灵敏且γ灵敏度约10-14C?cm2的电流型探测器的要求,介绍一种新型半导体探测器的物理设计思想,提供φ80mm×800μmPIN阵列探测器实物照片和部分性能参数测量结果。结果表明:可以通过改变构成探测器阵列的单一PIN探测器数量,使探测器阵列系统灵敏度在10-15～10-14C?cm2范围附近调节;当供电电压大于600V时,灵敏度已基本稳定;构成阵列探测器的单个探测器数量越多,时间响应波形展宽越多。

Abstract:Firstly,the Web Service model framework is introduced in this paper.Then,the application design of the distributed Web Service model based on .NET is discussed.Furthermore,the steps of how to develop the Web service in the .Net is expatiated in detail.And

Abstract:Although the developers can create complicated workflow application using Mail database and Lotus workflow tool on Lotus Domino platform,they have to pay more efforts.On Lotus platform,in order to create workflow application rapidly and decrease the workl

Abstract:在软件无线电的系统设计以及接收信号的数字化、软件化的实现中,数字下变频对信道访问起着重要作用。本文首先介绍了数字下变频的工作原理,然后详细分析了数字下变频的组成结构,讨论了接收机中数字下变频的概念和种类,分析了两种数字下变频频谱的特点,并推导了数字下变频在时域的表达式,最后给出了两种数字下变频适用的范围。

Abstract:Two kinds of vehicle synchronous orbiting satellite mobile communication systems are introduced.One is phased array antenna tracking UHF satellite mobile communication system;the other is laser gyro tracking Ku broadband satellite mobile communication sys