BDN染料的锁模特性和基态恢复时间

本文报道了国产BDN染料的碘乙烷溶液、吡啶溶液和二甲亚砜溶液的锁模特性和基态恢复时间。     

基于趋近律滑模最优控制的无人机撞网回收轨迹控制

针对舰载无人机撞网回收过程的下滑轨迹跟踪控制问题,在设计基于α β滤波器的轨迹控制外回路的基础上,着重设计了趋近律滑模控制与最优控制相结合的姿态控制内回路,提高了系统的稳定性并改善了系统的动态性能。以某小型无人机为例进行了撞网回收全过程三维数值仿真,仿真结果表明,该撞网回收着舰轨迹控制系统能够实现下滑过程飞行姿态及轨迹的精确控制,且能够在舰船甲板运动情况下实现较精确的撞网回收。     

Tree Recovery in PIM Sparse Mode

A PIM–SM-built multicast tree must be restructured when the underlying unicast routing tables change. We describe the PIM–SM recovery mechanisms and evaluate the recovery performance, showing its dependence on a range of network and session parameters. Our results show that a substantial packet loss can be caused by nonreductive, benign events in the network, such as an addition of a new link. We propose and evaluate an improvement to the standard PIM–SM recovery procedure aimed to reduce the packet loss caused by the benign events. Our evaluation shows that the data loss caused by these events can be significantly decreased regardless of the topology and session parameters.     

An Efficient Rerouting Scheme for MPLS-Based Recovery and Its Performance Evaluation

The path recovery in MPLS is the technique to reroute traffic around a failure or congestion in a LSP. Currently, there are two kinds of model for path recovery: rerouting and protection switching. The existing schemes based on rerouting model have the disadvantage of more difficulty in handling node failures or concurrent node faults. Similarly, the existing schemes based on protection switching model have some difficulty in solving problem such as resource utilization and protection of recovery path. This paper proposes an efficient rerouting scheme to establish a LSP along the least-cost recovery path of all possible alternative paths that can be found on a working path, which is calculated by the upstream LSR that has detected a failure. The proposed scheme can increase resource utilization, establish a recovery path relatively fast, support almost all failure types such as link failures, node failures, failures on both a working path and its recovery path, and concurrent faults. Through simulation, the performance of the proposed scheme is measured and compared with the existing schemes.     

适用于高阶QAM解调的载波恢复算法及其实现验证

高阶正交幅度调制（QAM）系统中,随着QAM信号阶数的提高,频偏和相偏对系统解调性能的影响越敏感,其对同步性能的要求也越来越高。因此,必须在接收端对系统中的频偏和相偏进行更精确的补偿,使得接收端与发送端的载波信号达到同频同相,来提高解调系统的性能。本文首先简单介绍了两种常用两种面向判决的载波相位恢复算法,并利用MATLAB／Simulink为该算法搭建了系统仿真模型进行分析,然后给出了具体的实现方法并对其性能进行了分析。仿真结果表明,面向判决的载波恢复算法实现简单,稳态时抖动较小,非常适用于高阶QAM解调系统。     

高阶QAM载波恢复的FPGA设计实现

本文介绍了适用于高阶QAM载波恢复的极性判决算法。该算法利用极性判决器捕获大概频偏,再利用DD算法跟踪并进一步纠正频偏,减小抖动误差,从而相较传统算法具有更好的频偏捕获能力和健壮性。同时,该算法能对两种算法模式进行自动切换以达到精确的频偏纠正目的。本文采用实用有效的MSE方法对这两种算法模式进行自动转换控制,并以128QAM为例对该算法进行MATLAB仿真分析。最后在FPGA平台上实现了128QAM的载波恢复算法,并且效果理想,有很好的移植性。     

制冷剂回收设备用压缩机容积系数对回收速度的影响

论述了制冷剂回收设备用压缩机容积系数的影响因素余隙容积、压力比、膨胀指数的大小变化对回收速度的影响情况。通过理论计算和实际验证认为余隙间隙和压缩比对回收速度的影响最大。     

分组密码算法CTC的立方分析

立方攻击是在2009年欧洲密码年会上由Dinur和Shamir提出的一种新型密码分析方法,该方法旨在寻找密钥比特之间的线性关系。CTC(Courtois Toy Cipher)是N.Courtois设计的一种用于密码分析研究的分组密码算法,该算法的密钥长度、明文长度和迭代轮数都是可变的。文中利用立方攻击方法针对密钥长度为60bit的4轮CTC进行了分析,在选择明文攻击条件下,结合二次测试可恢复全部密钥,密钥恢复阶段仅需要不到2~10次加密算法。     

一种新型的漂移阶跃恢复二极管脉冲源设计

提出了一种基于漂移阶跃恢复二极管（DSRD）、结构简单的新型大功率脉冲源电路.论述了阶跃恢复二极管的快速开关特性,分析了该新型脉冲源电路的工作原理,并进行了实验测试.实验结果表明,脉冲源电路能够产生峰峰值为760 V、脉宽（10％-10％）8 ns的平衡输出脉冲信号,具有脉冲重频高、振铃小、波形质量高、无需高压供电等特点,适用于深层探测超宽带时域脉冲探地雷达系统.     

具有消息恢复签名方案的伪造攻击

本文对具有消息恢复的数字签名方案的安全性进行了分析 ,对Nyberg和Rueppel提出的签名方案 (NR签名方案 )和Miyaji最近提出的签名方案 (F1)和 (F2 )分别设计了一种新的伪造攻击(ForgeryAttack)方法。