Improvement on threshold proxy signcryption scheme

Signcryption is a public key or asymmetric cryptographic method that provides simultaneously both message confidentiality and integrity at a lower computational and communication cost. This paper presents a （t, n） threshold proxy signcryption scheme in which no less than t proxy agents in the proxy group can produce the signcryption cryptogram. combines the functionality of threshold proxy signing and encryption. The proposed scheme combines the functionality of both threshold proxy signing and encryption, and provides fair protection for the sender and the proxy agents. This scheme is secure against attack of public key substitution. It also satisfies security properties such as confidentiality and authenticity.     

Magnetic properties of high-temperature superconductors: Analysis within the framework of the impurity mechanism

The impurity mechanism proposed earlier is used to interpret the magnetic properties of hightemperature superconductors. The appearance of superconductive granules and the existence of weak bonds in grains of ceramics and in single crystals is explained. The irreversibility line is obtained and its new interpretation as the line of thresholds of appearance of infinite nonsuperconductive cluster is given. The relaxation time of the magnetic susceptibility in alternating magnetic fields is calculated. The decrease of the Meissner fraction with increase in magnetic field and decrease in doping, and other magnetic properties are explained.     

图像阈值自动选取算法的C＋＋实现

图像分割是运动目标检测与跟踪技术必须要解决的问题,在很多时候它涉及到图像阈值的选取。文章采用的算法首先计算图像中不同区域的灰度均值,结合最小差值条件,反复修订由计算所得的阈值,从而达到自动选优的目的。在此基础上,文章进一步给出了用C＋＋语言实现算法的关键代码。测试表明此方法选择阈值简便实用,图像的二值化效果良好。     

"震网"引发网络安全新思考

本文概述了近期发生的"震网"事件.同时分析了"震网"的特点和行为特征.并根据我国的具体情况给出了安全警示和安全防范建议.     

New receipt-free voting scheme using double-trapdoor commitment

It is considered to be the most suitable solution for large scale elections to design an electronic voting scheme using blind signatures and anonymous channels. Based on this framework, Okamoto first proposed a receipt-free voting scheme [30] for large scale elections. However, in the following paper, Okamoto [31] proved that the scheme [30] was not receipt-free and presented two improved schemes. One scheme requires the help of the parameter registration committee and the other needs a stronger physical assumption of the voting booth. In this paper, we utilize the double-trapdoor commitment to propose a new receipt-free voting scheme based on blind signatures for large scale elections. Neither the parameter registration committee nor the voting booth is required in our scheme. We also present a more efficient zero-knowledge proof for secret permutation. Therefore, our scheme is much more efficient than Okamoto’s schemes [30] and [31] with the weaker physical assumptions. Moreover, we prove that our scheme can achieve the desired security properties.     

基于小波分析的听觉滤波器组模型

对听觉滤波器组模型进行了研究。比较分析了伽马通(Gammatone)听觉滤波器组模型和基于小波分析的高斯小波听觉滤波器组模型,分别给出了预测听阈曲线并且与标准听闻曲线进行了比较,结果表明高斯小波听觉滤波器组模型更接近实际人耳滤波效果。将高斯小波听觉滤波器组模型的预测特征响度与德国朗德(Head Acoustics)公司的Artemis软件计算出的特征响度进行分析比较,结果表明,每个特征频带的响度差值都小于0.6 sone。     

改进的基于梯度幅值的自适应边缘检测算法

分析文献[1]给出的算法.针对其中存在的问题和不足,给出了一个改进算法.实验结果表明,改进算法弥补了原文算法中的缺陷,在获取连续边缘的同时也较好地抑制了噪声,在运算效率方面有了明显的提升,并节省了大量的内存空间.     

一种基于软阈值方法的改进A1/A2极化干涉分类算法

在分析了极化干涉技术的发展现状和发展趋势的基础上,从极化干涉的特殊性入手,分析了干涉相干系数在极化干涉分类中的作用,并且系统分析了基于相干最优优化后的相干系数进行极化干涉分类过程的原理,总结了现有极化干涉分类算法在阈值选择方面存在的不足,阐述了硬阈值方法和软阈值方法的基本原理和它们之间的区别,最后提出基于软阈值方法的改进A1/A2非监督极化干涉分类算法,解决了极化干涉分类现有的分类空间中的阈值问题。实验表明这种方法能够得到更好的分类结果,做出了改进。     

Control of sonoluminescence signal in deionized water using carbon dioxide

Megasonic cleaning is routinely employed in semiconductor industry for cleaning of wafers. However, the method also results in damage to wafer features and such damage has been proposed to arise from transient, imploding cavities formed during megasonic processing. Transient cavitation is associated with the release of light, a phenomenon called sonoluminescence (SL) and the extent of damage has been shown to correlate with the intensity of SL. Control of sonoluminescence may therefore allow control of damage during megasonic processing of wafers. In this study, the ability of carbon dioxide to quench sonoluminescence generation in deionized water exposed to megasonic field of varying power density and duty cycle has been systematically investigated. It has been found that CO₂ is not only incapable but also a potent inhibitor of sonoluminescence, providing a potential means for selective alleviation of the violent effects of transient cavitation in process fluids. A novel chemical method has been established for in situ release of CO₂ from NH₄HCO₃ through a pH induced shift in the carbonic acid equilibria in deionized water. Using this method, a precisely controlled, progressive decrease in SL of air saturated deionized water through addition of NH₄HCO₃ has been demonstrated. It has been determined that 130 ppm of released CO₂ is sufficient for complete inhibition of sonoluminescence generated in air saturated deionized water.     

一种改进的可控制匿名性的离线电子现金系统

利用RSA盲签名算法和Schnorr一次数字签名算法,对Juels的电子现金方案[1]做了改进,提出一个新的可控制匿名性的电子现金系统。在用户向商家支付电子现金时,用户利用自己的秘密密钥对其将要支付的信息进行数字签名,解决了原方案中TTP(可信第三方)能冒充用户去花费用户的电子现金、他人获得合法用户的电子现金可盗用的问题,而且TTP使用公钥数字签名算法对可信标记签名,进一步增强了系统的安全性。最后对系统的安全性进行了分析。