Improved ant colony optimization algorithms for determining project critical paths

In project management, a project can be represented as a network in two ways; namely, activity-on-arc (AoA) and activity-on-node (AoN). Two recent papers have shown that ant colony optimization (ACO) could find critical path(s) in projects represented as AoA networks. This paper points out that the number and placement of logical dummy activities associated with AoA-based networks can pose serious problems. To get around the problems, an ACO technique based on AoN networks is then proposed. For comparison, the two existing AoA-based ACO algorithms were reproduced and modified into AoN-based algorithms. Moreover, the proposed ACO algorithm was applied to AoA networks as well. All six algorithms were tested with several benchmark problems. The test results strongly indicate that AoN-based ACO algorithms are more effective and efficient in finding critical paths than AoA-based algorithms.     

主变保护差动比率制动曲线的测试

介绍了目前常见的主变保护装置在差动保护两侧电流的移相方式及消除主变变比和TV变比对差动保护的影响上的不同,例举了常见主变保护差动比率制动曲线的测试方法。     

延迟双向联想记忆神经网络的周期振荡现象研究

带轴突信号传输延迟的双向联想记忆(BAM)神经网络是两层异联想网络,本文详细讨论带延迟BAM网络周期解的存在与唯一性,得到了一个充分条件;并用具体例子验证了所得结论的正确性。我们的结果对于具体的延迟BAM振荡神经电路的设计和应用具有重要的指导意义。     

磁滞及磁饱和效应对磁光光纤传感器的影响

给出了ＩｎＢｉＣａＶＩＧ晶体的磁滞回线,详细分析了磁滞及磁饱和效应对磁光光纤传感器的影响。当所测磁场信号为交变量时,磁滞的影响主要是相位延迟,对幅度及频谱分布影响较小;饱和效应不仅使响应幅值减小,同时还导致明显的频谱变化。     

增材制造TC4钛合金在激光抛光前后的电化学腐蚀性能

对表面已进行喷砂处理的增材制造TC4钛合金在氩气环境下进行激光抛光实验,通过极化曲线测试研究了抛光前、后钛合金的耐蚀性,并结合表面粗糙度、晶粒尺寸、表面残余应力以及显微组织分析了激光抛光对TC4钛合金耐蚀性的影响。研究结果表明:抛光钛合金的自腐蚀电位与自腐蚀电流密度均大于未抛光钛合金,说明抛光钛合金相比于原始钛合金的被腐蚀倾向更小,但其一旦受到腐蚀,腐蚀速率会略大于原始钛合金。自腐蚀电位的升高源于钛合金表面粗糙度的降低,自腐蚀电流密度的增大则是因为表面晶粒的细化以及残余拉应力的存在。     

基于IMS的多媒体彩铃业务的设计和实现

多媒体彩铃(MRBT)业务是一种采用多种媒体作为回铃音的增值业务.结合IMS网络体系结构和MRBT业务属性,提出一种利用多媒体彩铃业务平台来实现MRBT业务的方案,包括系统设计和基于SIP(会话发起协议)的信令流程.同时,给出相关的特点分析并进行总结.     

位置服务平台解决方案

本文讨论了东信北邮信息技术有限公司位置服务平台的系统总体结构设计、功能模块设计、进程拓扑图.     

基于JAIN SLEE的业务逻辑执行环境的设计与实现

本文简要分析了下一代业务逻辑执行环境(SLEE,Service Logic Execution Environment)JAIN SLEE规范,在此基础上给出了基于规范的SLEE设计与实现.     

矢量传感器误差校正与补偿

当阵列模型存在误差时,子空间类方法的高分辨性能会显著下降,因此必须进行有效的校正。由于矢量天线本身的复杂性,其相位误差很难精确校准且原有的基于标量天线相位误差的估计方法已经不再适应于矢量天线。该文在到达角已知情况下,给出了一种估计矢量天线阵列相位误差的新方法,并导出了各通道相位误差的计算公式。最后的数值模拟结果说明了本文方法是简单有效的。     

An efficient approach for DVB-H handover in DVB-H/UMTS hybrid networks

Handover in Digital Video Broadcasting for Handhelds （DVB-H） aims to provide continuous mobile broadcasting services when a user is traveling through cell boundaries. A good handover control can improve the power efficiency and gain much better reception quality. This letter provides a novel approach for DVB-H handover based on DVB-H/Universal Mobile Telecommunications System （UMTS） hybrid network, which moves the main handover function from the terminals to the networks, so that it reduces the operation complexity of the terminals and increases the power saving. When the terminal can not receive the DVB-H signal in the transmission shadow areas or because of some other reasons, the UMTS networks may offer the same service to users to make the service continuous. As the UMTS networks have the topology of the DVB-H networks, by communicating with the terminals, the UMTS networks can help the terminals to predict the handover, and avoid unnecessary handover.