罗兰-C信号快速捕获方法及其性能分析

罗兰-C系统与全球导航定位系统(GNSS)相结合已成为新的应用模式,为用户提供可靠的定位、导航和授时服务。针对传统罗兰-C接收机信号捕获时间长、抗噪性能差等缺点,该文提出一种基于延迟相关技术的罗兰-C信号抗噪快速捕获方法,并从理论分析和仿真实验两个方面验证了该方法的有效性,解决了强噪声背景下罗兰-C信号的快速捕获问题。结果表明：罗兰-C延迟相关捕获方法的捕获时间优于200 ms,抗噪性能优于-10 dB。     

Automatic,fast, online calibration between depth and color cameras

Automatic camera calibration has remained a hard topic in computer vision since its inception due to its reliance on the image correspondence problem. This problem becomes even more pronounced when calibrating a depth image with a color image due to a lack of simple correspondences between the two modalities. In this work, we develop a completely automatic, very fast, online algorithm that demonstrates how a consumer-grade depth camera can be calibrated with a color camera with minimal user interaction.     

基于FPGA的简易频谱分析仪

观测信号频谱在科研中具有重大意义.在教学实验中也有利于学生更直观深入地了解信号特征.采用单片机C8051和FPGA.外加高速A/D转换器设计一种简易的频谱分析仪.该系统主要包括信号采集、频谱搬移、数字滤波、数字FFT和LCD显示.经测试.该系统能够分析信号带宽为0～5 MHz,最低分辨率达到1 Hz.而且信号频谱图能够很好地显示在LCD上.整个系统工作稳定,操作方便,且成本比其他频谱分析仪低很多.     

Protected session keys context for distributed session key management

Handoffs must be fast for wireless mobile nodes (MN) without sacrificing security between the MN and the wireless access points in the access networks. We describe and analyze our new secure Session Keys Context (SKC) scheme which has all the good features, like mobility and security optimization, of the currently existing key distribution proposals, namely key-request, pre-authentication, and pre-distribution. We analyze these solutions together, and provide some conclusions on possible co-operative scenarios and on which level of the network to implement them. Finally before conclusions we provide some handoff delay simulation results with SKC and key request schemes with corresponding example handoff scenarios with a next generation radio link layer.     

一种可快速关断的新型横向绝缘栅双极晶体管

提出了一种可快速关断的新型横向绝缘栅双极晶体管(LIGBT)。在LIGBT关断时,利用一个集成的PMOS晶体管来短路发射结,以获得短的关断时间。PMOS晶体管由LIGBT驱动,不需要外部驱动电路。新器件在没有带来任何副作用(如snap-back现象和工艺制造上的困难)的情况下,获得了低的导通压降和快的关断速度。数值仿真结果表明,新器件在不增加导通压降的同时,将关断时间从120ns降到12ns。     

单探测器型复合轴系统设计中的若干问题

针对单探测型复合轴系统设计中存在的控制回路耦合问题,脱靶量解算问题和实时稳定补偿问题,进行了详细分析和推导。首先,给出了系统设计中控制回路耦合的解耦控制方案;其次,推导了探测器获得的脱靶量和快速反射镜(Fast Steering Mirror,FSM)补偿角度之间精确的数学表达式;最后,提出了一种通过实时解算稳定误差,并利用高带宽和高精度的FSM对误差进行高精度补偿的方法。这些方案和表达式可有效地解决设计中的原理性问题和误差解算问题,进而提高系统精度,因此具有相当大的实用性。     

基于信令数据的轨迹驻留点识别算法研究

针对密度聚类算法只能识别密度相近的簇类且计算复杂度高等问题,该文提出一种基于信令数据中时空轨迹信息的密度峰值快速聚类(ST-CFSFDP)算法。首先对低采样密度的信令数据进行预处理,消除轨迹震荡现象;然后基于密度峰值快速聚类(CFSFDP)算法显式地增加时间维度限制,将局部密度由2维扩展到3维,并提出高密度时间间隔以表征簇中心在时间维度上的数据特征;接着设计筛选策略以选取聚类中心;最后识别用户出行轨迹中的驻留点,完成出行链的划分。实验结果表明,所提算法适用于采样密度低且定位精度差的信令数据,相比CFSFDP算法更适用于时空数据,相比基于密度的时空聚类算法(ST-DBSCAN)召回率提升14%,准确率提升8%,同时降低计算复杂度。     

Self-learning residual model for fast intra CU size decision in 3D-HEVC

As an extension of the High Efficiency Video Coding (HEVC) standard, 3D-HEVC requires to encode multiple texture views and depth maps, which inherits the same quad-tree coding structure as HEVC. Due to the distinct properties of texture views and depth maps, existing fast intra prediction approaches were presented for the coding of texture views and depth maps, respectively. To further reduce the coding complexity of 3D-HEVC, a self-learning residual model-based fast coding unit (CU) size decision approach is proposed for the intra coding of both texture views and depth maps. Residual signal, which is defined as the difference between the original luminance pixel and the optimal prediction luminance pixel, is firstly extracted from each CU. Since residue signal is strongly correlated with the optimal CU partition, it is used as the feature of each CU. Then, a self-learning residual model is established by intra feature learning, which iteratively learns the features of the previously encoded coding tree unit (CTU) generated by itself. Finally, a binary classifier is developed with the self-learning residual model to early terminate CU size decision of both texture views and depth maps. Experimental results show the proposed fast intra CU size decision approach achieves 33.3% and 49.3% encoding time reduction on average for texture views and depth maps with negligible loss of overall video quality, respectively.     

快速轨道交通无线通信频段的选择和频率配置

探讨了城市快速轨道交通中无线通信频段的选择及频率配置问题,介绍了一种用无线电频率管理程序提高频率利用率的方法。