放大转发中继网络中绿色的物理层安全通信技术

该文基于物理层安全理论,针对能量受限的无线中继网络提出一种绿色的保密通信方案。该方案在节点功率约束和系统最小目标保密速率要求下,通过最优功率控制实现系统的安全能效最大化,并基于分式规划、对偶分解和DC(Difference of Convex functions)规划理论提出了一种迭代的功率分配算法。通过仿真比较,能效优化可以显著提升系统的安全能效,然而相对于保密速率最大化会有一定保密速率损失,这是由于能效和保密之间存在固有的折中。但是,能效优化的保密速率仍然大于发送总功率最小化的保密速率。     

A Novel Quarter-Circular Arc Multi-Direction Piezo electric VEH and Its Theoretical Model

A quarter-circular arc piezoelectric Vibra-tion energy harvester (VEH) based on nonlinear geometry is proposed with both bending moment and torque deformation mode, so it can effectively absorb multi-directional vibration at the same resonance frequency. The theoretical model of quarter-circular arc piezoelectric VEH is established to study the resonance frequency and the output voltage. In order to demonstrate multi-directional performance of the quarter-circular arc VEH, the stress distribution is compared with that of the traditional piezoelectric VEH in multi-direction vibration, and the output voltage of the circular arc piezoelectric VEH are relatively increased 267.26％ in X-direction, 463.18％ in Y-direction, and 17.24％ in Z-direction. The external load is equipped in circuit to measure output power, whose matching resistance is around 21k?, and the maximum output powers are 7.57mW in X-direction, 2.39mW in Y-direction, and 9.93mW in Z-direction.     

DRM广播外辐射源雷达模拟信号源设计

DRM数字调幅广播在全球获得蓬勃发展,但目前可收听时段较为有限.为开展DRM新体制外辐射源雷达预研的需要,给出了一种DRM外辐射源雷达模拟信号源的软硬件实现方法.基于DRM信号结构分析了基带信号的产生和接收信号的数学模型;介绍了硬件平台结构、实现方法和工作流程,并通过双通道合成输出,成功模拟了直达波与目标回波信号;通过后续信号处理准确地提取了目标信号的时延多普勒信息.试验结果表明,模拟信号源能够满足外辐射源雷达的预研需求,为基于实测数据的目标提取等算法奠定了基础.     

非醇醚类助焊剂及其焊膏的研究

研究了多元醇类溶剂及其复配物对Sn0.3Ag0.7Cu焊膏性能的影响。结果表明:四氢糠醇和聚丙二醇对冰白和水白松香都具有较强的溶解性。当四氢糠醇和聚丙二醇以质量比9:1复配时,获得的焊膏平均铺展率可达87%以上,焊点完整、饱满、无焊球和桥连等缺陷,储存时间较长,是一种综合性能良好的焊膏。     

基于STM32的医疗康复室智能家居系统

本文提出一种基于红外通信互联的、可无线操控的医疗康复室智能家居系统设计.此系统一方面实现了家居设施的智能控制,同时可由护士及病患通过红外、语音两种方式对各类家居进行遥控,另一方面红外无线通信具有低功耗、低电磁干扰等优点,减轻了环境中辐射对病人的伤害.这分担了护士的工作,让护士专注于病人病情的诊查,还有利于病人的康复.     

Weak signal detection and adaptive synchronous stability of a novel fifth-order memristive circuit system

This paper is devoted to introduce a novel complex fifth-order memristive circuit system and its applications in synchronous stability and weak signal detection. Firstly, the typical dynamical behaviors of the memristive system are discussed by chaotic phase portrait, complexity analysis, one-parameter bifurcation and Lyapunov exponent spectrum. Secondly, the adaptive control method is applied to realize the synchronization between the drive memristive system (DMS) and the response memristive system (RMS). The results indicate that the synchronization method has strong robustness and anti-interference ability. Thirdly, the weak signal detection of the novel five-dimensional memristive system is realized by using the extreme sensitivity of chaotic system to initial values. Finally, the fifth-order memristive circuit is designed by using basic electronic elements and simulated by Multisim software. And the anti-interference ability and sensitivity of the fifth-order memristive circuit are further verified by adding different weak disturbance signals at different positions of the circuit.     

基于微波多层板的小型化多通道接收前端设计

基于微波多层板技术,通过对单片微波集成电路(MMIC)、微机电系统(MEMS)和低温共烧陶瓷(LTCC)滤波器等微组装工艺的优化和分析,使多通道接收前端进一步实现小型化设计和应用。同时,对电路和结构进行改进,使前端组件具有更好的幅相一致性和高隔离度。最终实现的C频段四通道接收前端尺寸为120 mm×50 mm×12 mm,幅相一致性分别小于±0.8 d B和±5°,通道间隔离度高于60 d Bc。该设计方法的实现为小型化多通道接收前端的工程化应用提供了一种有效的解决方案。     

LTE核心网与PTN组网方案研究

研究了LTE核心网集中部署时PTN网络的组网方案,在此基础上分析了未来LTE核心网规模扩大局点分裂或下沉后PTN网络可能的组网演变,以期为LTE核心网与PTN承载网的合理组网提供借鉴。     

基于高精度边缘方向求解的红外弱小目标检测

针对边缘方向误差较大导致各向异性 SUSAN 算法背景抑制能力降低的问题,提出了一种高精度边缘方向求解算法来确定实际边缘方向;并引入独立强度模型来确定短轴的尺度以实现滤波器长、短轴自适应地确定。实验表明：高精度边缘方向求解算法的引入能显著提升红外背景重建的精确度,从而提高了算法的背景抑制能力,经过该算法滤波后的图像其信噪比、检测率都获得显著提升,虚警率明显降低,能有效提高系统的单帧红外弱小目标的检测能力。     

信号频率和到达角联合估计新方法

提出了一种类L型阵,并运用快速子空间法得到噪声子空间,然后进行频率、到达角二维搜索。此方法阵元结构简单,物理易实现;无需特征分解,计算量大大降低;参数估计精度较高,与多抽头MUSIC方法相当。仿真试验证明了此方法的可行性。