A novel 1D chaotic system for image encryption,authentication and compression in cloud

Multimedia Tools and Applications - To solve the privacy image problem stored in cloud, we propose a compressive sensing (CS) based image compression, authentication, encryption algorithm in cloud,...     

A novel elevator group control algorithm based on binocular-cameras corridor passenger detection and tracking

Multimedia Tools and Applications - The conventional elevator arrives at the floor in response to the user request and where is to dispatch an elevator car. There is one big problem that when...     

焦炉煤气原位整体式干法样气处理系统研究与实践

焦炉煤气样气处理系统是在线分析样气处理系统的技术制高点之一,焦炉煤气中的焦油、萘等有害污染物的处理非常困难,至今都未能完全解决。本研究提出的焦炉煤气原位整体式干法样气处理系统,能够很好适应焦炉煤气含尘量高,焦油和萘污染严重的特殊样气条件,具有体积小、免维护、零排放和响应快速的优点。采用该样气处理系统组合构建的焦炉煤气干法防爆氧分析系统已进入工程应用考核阶段。本设计的原位处理和原位分析,由于是干法样气处理技术,能够实现氧含量的高准确度在线分析,对安全生产有特殊的重要意义。     

高温下奥克托今单晶冲击响应数值计算

为研究奥克托今(HMX)单晶在高温下的冲击响应,发展了基于热激活和声子拖曳位错滑移机制的非线性热弹黏塑性模型。该模型可再现平板撞击实验中HMX单晶Hugoniot弹性极限(HEL)的热硬化效应。通过定量分析声子散射和辐射阻尼对热硬化效应的影响,可研究373 K、423 K高温下受冲击HMX单晶位错滑移机制演变以及相关热力学响应。结果表明：随着初温由300 K升 高至423 K,声子散射和辐射阻尼效应增强导致声子拖曳系数增大,使可移动位错黏性摩擦增强,平均位错速度由2 237 m/s减小至1 537 m/s,进而产生较低的塑性剪应变率和较高的流动应力,引起HMX单晶HEL的热硬化效应;剪切模量随着初温升高变化较小(约1.0 GPa),导致辐射阻尼对热硬化效应的贡献小于声子散射。     

缓冲区溢出攻击的防护技术分析

缓冲区溢出攻击已经成为网络攻击的主要方式.本文首先分析了缓冲区溢出攻击的基本原理,然后分析了形成缓冲区溢出攻击的必要条件,并详细讨论了溢出攻击的防护技术.     

无刷励磁发电机可靠性设计研究

无刷励磁机之励磁机电枢绕组由多路并联改为一路并联,可减少端部连线,减少故障环节.通过对并联支路改进前后性能比较,提出优化设计方案.     

基于改进型序阻抗原理的变压器保护方案

基于序阻抗原理的变压器保护方案利用变压器发生区内外故障时,变压器两侧正负序阻抗所在象限的不同,来有效识别变压器区内外故障,文中在此方案基础上,改进了象平面区域的划分,补充了励磁涌流识别判据,并讨论了在特殊情况下所应采取的措施.在构建电流互感器饱和模型的基础上,利用HYBRISIM进行了大量的仿真实验,仿真结果表明:基于改进型序阻抗原理的保护方案,较原方案在保护动作的可靠性和灵敏性等方面均有较大的改善和提高,与传统的比率制动型差动保护相配合,可构成一种较理想的变压器主保护方案.     

间隙法测量矩形角尺外角的不确定度分析

矩形角尺在实验室检测、现场调试的运用越来越广泛。矩形直角尺的检定及校准,既可以通过测微表直接测量,也可以通过间隙法间接测量。文章主要介绍间隙法测量0级及以下矩形角尺外角的不确定度分析。     

分层地电模型的正演递推关系

通过对分层地电模型中电磁波传播的路径分析。我们导出了一种逐向层向上的地电系统正演迭代关系。研究了系统函数特性，可以得出：１．层次地电结构对于垂直入射电磁波的脉冲响应为低通特性；２．在低频端，浅层路径对于深层界面反射的掩盖是严重的；３．根据脉冲响应反演分层参数存在着不适定性。     

Robust palmprint identification based on directional representations and compressed sensing

In this paper, we propose a novel approach for palmprint recognition, which contains two interesting components: directional representation and compressed sensing. Gabor wavelets can be well represented for biometric image for their similar characteristics to human visual system. However, these Gabor-based algorithms are not robust for image recognition under non-uniform illumination and suffer from the heavy computational burden. To improve the recognition performance under the low quality conditions with a fast operation speed, we propose novel palmprint recognition approach using directional representations. Firstly, the directional representation for palmprint appearance is obtained by the anisotropy filter, which is robust to drastic illumination changes and preserves important discriminative information. Then, the principal component analysis (PCA) is used for feature extraction to reduce the dimensions of the palmprint images. At last, based on a sparse representation on PCA feature, the compressed sensing is used to distinguish palms from different hands. Experimental results on the PolyU palmprint database show the proposed algorithm have better performance than that of the Gabor based methods.