Vehicle and pedestrian detection method based on improved YOLOv4-tiny

Aiming at the problem of low detection accuracy of vehicle and pedestrian detection models, this paper proposes an improved you only look once v4 (YOLOv4)-tiny vehicle and pedestrian target detection algorithm. Convolutional block attention module (CBAM) is introduced into cross stage partial Darknet-53 (CSPDarknet53)-tiny module to enhance feature extraction capabilities. In addition, the cross stage partial dense block layer (CSP-DBL) module is used to replace the original simple convolutional module superposition, which compensates for the high-resolution characteristic information and further improves the detection accuracy of the network. Finally, the test results on the BDD100K traffic dataset show that the mean average precision (mAP) value of the final network of the proposed method is 88.74%, and the detection speed reaches 63 frames per second (FPS), which improves the detection accuracy of the network and meets the real-time detection speed.     

区块链电子存证系统的设计与实现

文中介绍了区块链技术在电子证据存证方面的应用。通过将需要的电子证据以交易的形式记录下来,并明确记录时间戳,然后将记录存储在节点账本中。利用分布式数据存储技术完成电子存证过程,区块链技术可以实现不可篡改的信息存取和交换,有效保证电子数据的安全性和可信性。文中还探讨了区块链技术在降低处理电子证据时的技术风险和存储成本以及其对司法机构的协助作用。     

Numerical research on mid-infrared supercontinuum generation in Ge11.5As24Se64.5 few-mode photonic crystal fibers

Based on the nonlinear and mode coupling effect in few-mode photonic crystal fiber (FM-PCF), an approach for supercontinuum (SC) generation in the mid-infrared (MIR) region is proposed. The propagation characteristics of Ge11.5As24Se64.5 FM-PCF have been analyzed and optimized by the full-vector finite element method. The two-mode generalized nonlinear Schrodinger equation (TM-GNLSE) is set up, and the SC generation has been analyzed by the split-step Fourier method. The SC from 1.80 μm to 11.32 μm is generated by pumping 3.0-cm-long fiber at the central wavelength of 3.0 μm, the peak power of 120 W, and the pulse duration of 250 fs.     

基于测量误差不确定性加权的快速相机位姿估计算法

在相机位姿估计任务中,参考点位置的测量容易受测量仪器或者所处环境影响,出现一定程度的测量误差,其中误差较大的点对最终求解精度的影响很大,被称为野值点。文章针对现有算法抗野值点能力较弱的问题,提出一种基于测量误差不确定性加权的快速相机位姿估计算法。该算法以经典的正交迭代算法为基础,引入M估计方法,对目标函数根据参考点的测量误差赋予相应大小的权值,最大程度地将野值点的影响排除,并引入Kronecker积对计算过程进行优化,减少了迭代过程中的冗余计算,提高运算速度。仿真实验结果表明,改进后的算法提升了原算法的抗野值点能力,且计算速度更快。     

民航空管系统空中交通管理生产数据中心建设分析

随着民航空管事业的快速发展,运输量也越来越大,如果单靠人力很难做到对民航空管系统的有效管控,信息化技术可为民用航空发展提供强有力的技术支撑,通过建立数据中心可将空中交通管理经验储存起来,从而为民航提供更加精准、及时的服务信息,使民航空管的安全水平和服务质量得以提高,这也是民航建设的最终目标。     

一种Ku波段综合馈电多功能板的研制

基于多层微波数字复合基板层叠互联技术,研制的Ku波段综合馈电多功能板集成了射频收发网络、电源分配网络、阵面波控及波控分配网络,主要负责16个片式T/R组件的功率分配与合成,同时为各T/R组件提供电源及控制信号。文中对多功能板的架构设计、工作原理进行了说明,重点介绍了各微波垂直互联电路和射频收发网络的设计,最后加工并测试了验证样件,测试结果良好。收发网络总口驻波＜1.9,分口驻波＜1.3,插损＜16 dB,相邻端口的隔离度＞20 dB,且幅度一致性≤0.602 dB,相位一致性≤6.429°。工程应用可行性和实用性得到了验证。