基于代价策略的H.264/AVC半脆弱水印算法

In order to solve some existing problems on detecting malicious tampering by video watermarking based on H.264/AVC video compression standard,a semi-fragile video watermarking algorithm for H.264/AVC based on cost strategy was proposed.To further improve the robustness of the feature codes in semi-fragile video watermarking algorithm,a new generation algorithm for feature codes by eliminating the correlation of them was proposed.In order to meet the requirement that the semi-fragile watermarks should be uniformly embedded into the video frames to locate the tampered region accurately,a minimal cost function was introduced to select a DCT coefficient in the 4 × 4 block residual to embed watermark which had minimal impact on the video quality and bit rates.Experimental results show that the proposed algorithm can significantly reduce impact on video quality and bit rate because of embedding the watermarking by adopting the minimum cost function and it is sensitive to malicious manipulations.The retrieved feature code and watermarking can detect and locate malicious manipulations.     

刍议生物制药中的细胞工程

细胞工程,有时也称动物细胞技术,是生物技术领域中重要的组成部分,它是利用动物细胞体外培养和扩增来生产生物产品,或者作为发现和测试新药的工具。如今这一技术已广泛应用于现代生物制药的研究和生产中。本文针对细胞工程在生物制药中的广泛应用进行了研究,重点分析了悬浮培养技术在生物制药工业中的地位。     

空冷机组喷雾降温系统的设计研究

在夏季高温时节,空冷发电机组通常不能满发.采用喷雾降温系统后,可提高空冷塔散热器进风侧的换热性能,降低汽轮机背压,提高机组的出力.结合直接空冷和间接空冷机组中的应用实例,对汽轮机背压、环境温度、喷雾水量等参数进行计算分析,并优化了喷淋泵组、喷嘴型式、电气控制等相关配置,提出了完整的设计思路和解决方案.     

不同钙含量、不同白度滑石粉的应用

义是华泰集团公司对低钙低白度、低钙高白度、高钙高白度的滑石粉进行了对比研究,分析不同钙含量、不同白度的滑石粉在实际生产中的应用效果。义是滑石粉的特性见表1。义是经实验试验和生产应用得出如下结论:不同钙含量、不同白度的滑石粉各有优缺点。生产试验在1760mm长网纸机进行。纸机车速240m/min,使用80注:#1为低钙低白度滑石粉,#2为低钙高白度滑石粉,#3为高钙高白度滑石粉。#1、#3为山东境内滑石粉,#2为辽宁滑石粉。表1不不同滑石粉的特性比较编号白度%筛余物%CaCO3含量 %沉降速度ml/15min烧失量%#1#2#378.386.690.91.31.51.0 4.6 1…     

双足机器人NAO爬楼步态规划

双足机器人的爬楼梯性能是衡量其在复杂环境下行走能力的一项重要指标.本文针对双足机器人NAO爬楼梯步态规划问题,提出一种离线步态规划方法：基于几何法建立机器人爬楼梯逆运动学模型;将运动解耦为前向运动和侧向运动,对于起步、中步和止步三个阶段,采用加速度空间法和几何约束规划法,计算各关节运动轨迹,并基于其逆运动学模型,得到各关节角序列;分别基于NAOSim和NAO进行虚拟样机仿真实验和实物样机验证.实验结果表明,步态规划方法合理有效.     

An investigation on electrochemical performances of as-cast and annealed La0.8Mg0.2Ni3.3Co0.2Six（x = 0-0.2） alloy electrodes for Ni/MH battery application

The La-Mg-Ni-based A2B7-type La0.5Mg0.2Ni3.3Co0.2Six （x=0-0.2） electrode alloys were prepared by casting and annealing. The influences of the additional silicon and the annealing treatment on the structure and electrochemical performances of the alloys were investigated systemically. Both of the analyses of XRD and SEM reveal that the as-cast and annealed alloys are of a multiphase structure, involving two main phases （La, Mg）2Ni7 and LaNi5 as well as one minor phase LaNi3. The addition of Si and annealing treatment bring on an evident change in the phase abundances and cell parameters of （La, Mg）2Ni7 and LaNi5 phase for the alloy without altering its phase structure. The phase abundances decrease from 74.3% （x=0） to 57.8% （x=0.2） for the （La, Mg）2Ni7 phase, and those of LaNi5 phase increase from 20.2% （x~0） to 37.3% （x=0.2）. As for the electrochemical measurements, adding Si and performing annealing treatment have engendered obvious impacts. The cycle stability of the alloys is improved dramatically, being enhanced from 80.3% to 93.7% for the as-annealed （950 ℃） alloys with Si content increasing from 0 to 0.2. However, the discharge capacity is reduced by adding Si, from 399.4 to 345.3 mA.h/g as the Si content increases from 0 to 0.2. Furthermore, such addition makes the electrochemical kinetic properties of the alloy electrodes first increase and then decrease. Also, it is found that the overall electrochemical properties of the alloys first augment and then fall with the annealing temperature rising.     

浅谈高效学生择业跟踪分析系统的设计

就业,对于毕业生来说是一个至关重要的问题,是否能成功就业将直接影响毕业生的未来.而就业对于高校来说,毕业生的就业率同样也是影响其教育教学发展的重点要素.在当今的大数据时代,收集、整理与挖掘毕业生的就业数据,是指导高校制定更加优良的人才培养方案、教学计划和安排的必要工作.随着毕业生的逐年增加,就业数据的收集与整理对于高校来说都是一个痛点.所以,依托现代技术整理与分析就业数据,建立一个便捷、有效的就业信息管理系统的工作迫在眉睫.     

脱墨剂的起泡性能及其泡沫稳定性

对表面活性剂的起泡性能和泡沫稳定性进行了研究,研究结果表明,单一表面活性剂中起泡效果最好的是LCS;而2种表面活性剂复配后起泡效果最好的是m(LWE-7)∶m(LCS)=1∶2以及m(WNL-9)∶m(LCS)=1∶2。     

新闻纸机胶粘物控制的实验室评估

在实验室条件下评估国外某公司酶产品处理新闻纸脱墨浆中胶粘物的效果,为实际应用提供依据.