分布式压缩视频编码的帧分类重构方法研究

在很多的应用场景中需要具有低复杂度的视频编码器,新兴的分布式视频编码和压缩感知技术正好适用于这些场景中,因而出现了一种新的视频编码方案——分布式压缩视频编码。在现有的一些分布式压缩视频编码方案中,视频帧在编码端是独立编码,在解码端进行联合解码,具体来说就是关键帧独立解码,非关键帧在由关键帧生成的边信息的帮助下进行解码,这就忽略了非关键帧之间的相关性。本文提出一个新的分布式视频编码方案,将非关键帧分为主非关键帧和次非关键帧,主非关键帧利用关键帧生成地边信息进行解码,而次非关键帧先利用相邻的主非关键帧进行观测值预测,然后再利用关键帧生成的边信息进行解码。实验结果表明,在本文提出的框架下,非关键帧的重构质量提高了有2dB~4dB。      

信息安全管理与对策

随着信息技术的发展和信息化建设的高速推进,网络安全问题日益突出.针对信息安全面临的各种威胁,提出了这些安全问题的解决方法,如防火墙技术、VPN技术、入侵检测技术(IDS)等,同时分析了企业信息的安全管理策略.通过这一系列的安全技术和安全管理,使得网络信息更加安全可靠.     

Corrosion behaviors of arc spraying single and double layer coatings in simulated Dagang soil solution

Three kinds of single layer coatings of Zn, Zn15Al, 316L stainless steel and two kinds of double layer coatings with inner layer of Zn or Zn15Al and outer layer of 316L stainless steel by arc spraying were developed to protect the metal ends of prestressed high-strength concrete (PHC) pipe piles against soil corrosion. The corrosion behaviors of the coated Q235 steel samples in the simulated Dagang soil solution were investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and natural immersion tests. The results show that the corrosion of the matrix Q235 steel is effectively inhibited by Zn, Zn15Al, Zn+316L and Zn15Al+316L coatings. The corrosion rate value of Zn15Al coated samples is negative. The corrosion products on Zn and Zn15Al coated samples are compact and firm. The corrosion resistance indexes of both Zn and Zn15Al coated samples are improved significantly with corrosion time, and the latter are more outstanding than the former. But the corrosion resistance of 316L coated samples is decreased quickly with the increase in immersion time. When the coatings are sealed with epoxy resin, the corrosion resistance of the coatings will be enhanced significantly.     

受火后CFRP布加固钢筋混凝土梁受剪性能试验研究

通过2根未受火钢筋混凝土梁、2根受火后钢筋混凝土梁和4根受火后CFRP布加固钢筋混凝土梁的静载试验,研究了剪跨比、CFRP布加固量和楼板翼缘对受火后钢筋混凝土梁受剪加固效果的影响。采用自编有限元程序分析受火损伤的混凝土梁截面通过等截面修复后截面混凝土抗拉强度的平均折减系数,提出受火后CFRP布加固钢筋混凝土梁受剪承载力的实用计算方法。研究结果表明:加固梁破坏时,外包的CFRP布发生拉断破坏,"U形包裹加压条"的CFRP布发生剥离破坏;受火后外包CFRP布加固混凝土矩形梁的受剪承载力相比未受火钢筋混凝土梁提高了5.3%~16.6%;受火后"U形包裹加压条"方式加固混凝土T形梁的受剪承载力相比对应未受火矩形梁提高了34.0%。提出的受火后CFRP布加固钢筋混凝土梁受剪承载力的计算式具备一定的安全保证率,可用于该类构件受火后的受剪加固计算。     

磷化/硅酸盐溶胶封闭后处理复合膜的自愈机理(英文)

通过磷化/硅酸盐溶胶封闭后处理技术,在镀锌钢表面生成完整的复合膜。采用X射线光电子能谱研究复合膜的化学组成。将复合膜用刀片划伤至露出锌层,经中性盐雾(NSS)腐蚀若干时间后,采用SEM和EDS研究划痕表面腐蚀产物的显微组织和化学成分,并与未划伤的腐蚀试样进行对比。探讨复合膜的自愈机理。结果表明,在腐蚀过程中,复合膜溶解出的自愈性离子扩散迁移至划痕表面或缺陷处,与Zn2+重新结合生成不溶性化合物,覆盖划痕或缺陷表面。腐蚀产物中含有Si、P、O、Cl和Zn五种元素,为致密细小的针片状,能较好阻滞裸露锌层腐蚀的形成和扩展。复合膜具有良好的自愈性能。     

热力学计算与动力学模拟在材料设计中的应用探索

介绍了材料设计的研究现状,利用热力学计算与动力学模拟方法预测了不同制备条件下复合材料、梯度材料及聚合物太阳能电池的组织演化。结合材料设计理念,提出通过改变混合体系的成分、淬火条件等,从制备过程中组织结构演化控制材料的形态获得所需性能材料的材料设计思路。     

胶质磷酸钛表调预处理对热镀锌层表面磷化膜的影响

通过扫描电镜(SEM)分析、磷化膜增重和开路电位-磷化时间的测量及中性盐雾(NSS)试验,研究了胶质磷酸钛表调预处理对热镀锌层表面磷酸锌转化膜的影响.结果表明,热镀锌钢经胶质磷酸钛表调预处理后再磷化,与不经表调直接磷化相比,磷酸锌晶体的形核率与生长速率明显提高,可获得较细小致密的磷酸锌晶体和较大的膜层增重;且前者由于磷酸锌晶体细化和覆盖率提高,磷化膜的耐蚀性也有所增强.     

PHC管桩三种常用金属端头在土壤模拟液中的电化学腐蚀行为

金属端头的耐蚀性取决于其各部件(包括端板、裙板和主筋)的材质,进而影响预应力高强混凝土管桩(PHC管桩)的耐久性。通过自然浸泡和电化学测量技术研究了实际工程中PHC管桩三种常用金属端头(其中端板分别用铸钢、冷弯钢和Q235A钢)在四种典型土壤(氯盐土、盐碱土、中性草甸土和酸性红土)模拟液中的腐蚀行为。结果表明,实际工程所用端板的腐蚀速率均小于主筋和裙板,铸钢端板加速裙板和主筋腐蚀的程度不如冷弯钢或Q235A钢端板,但铸钢端板本身耐蚀性极差;端板与裙板、端板与主筋在土壤中存在接触电偶腐蚀,端板/裙板电偶对中裙板均为阳极,铸钢端板/主筋电偶对在盐渍土中铸钢为阳极,冷弯钢或Q235A钢端板与主筋电偶对中主筋也均为阳极;接触腐蚀加速了薄壁裙板和小面积主筋的破坏,将导致预应力的过早失效;现有金属端头需进行防腐蚀控制。     

Electrochemical corrosion behavior of arc sprayed Zn and Zn15Al coatings in simulated salina soil and neutral meadow soil solutions

Arc sprayed Zn and Zn15Al coatings were chosen to protect the metal ends of prestressed high-strength concrete (PHC) pipe piles against corrosion of salina soil in northern china and neutral meadow soil in northeast China. The corrosion behavior of the coated Q235 steel samples in two simulated soil solutions were investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. The experimental results show that the corrosion of the matrix Q235 steel in both simulated solutions is remarkably inhibited by Zn and Zn15Al coatings. The corrosion products on Zn and Zn15Al are thick, compact, firm and protective. The corrosion current density icorr of both Zn and Zn15Al-coated samples is decreased evidently with corrosion time, and the charge transfer resistance Rct is increased greatly. The corrosion resistance indexes of Zn and Zn15Al in simulated neutral meadow soil solution are more outstanding than those in salina soil. The corrosion resistance of Zn15Al in salina soil is slightly superior to that of Zn. When the sprayed coatings are sealed with epoxy resin, the corrosion resistance of the coatings is further enhanced markedly.     

分布式压缩感知视频编码中CS帧的二次修正准则研究

分布式视频编码是新的视频编码体系,与传统的视频编码体系相比,具有编码端相对简单、解码端相对复杂的特点。此外,压缩感知突破了奈奎斯特采样定理,降低了信号的采样率。将压缩感知理论应与分布式视频编码相结合,使编码端复杂度降低。在一些分布式压缩视频编码研究中,CS帧是由边信息和发送端传送的信息联合重建的,由于不同CS帧的边信息的预测准确度不同,导致不同CS帧恢复质量相差较大。为了解决这个问题,本文对CS帧的二次修正准则的进行研究,首先从理论上推导出方差作为修正准则的可行性,并在实验中加以验证。实验可知,本文提出的方法在一定程度上改善了这些帧的重建质量。