信号相关杂波背景中极化雷达发射波形优化

波形优化可有效抑制干扰,显著改善雷达探测性能.针对全极化雷达,考虑发射波形满足能量和相似性双重约束,以最大化信杂噪比为准则,对发射波形和接收滤波器进行联合优化.该文设计了一种波形和滤波器的迭代优化算法,该方法序贯提高输出信杂噪比.算法的每一次迭代需要分别解决一个凸问题和隐凸问题,整个算法的计算量与迭代次数和接收滤波器长度分别呈线性和多项式关系.最后,通过仿真实验分析了算法的收敛性、优化波形的模糊度函数方面的性质,与其他算法进行了对比,结果表明:与现有方法相比,该文方法可实现信杂噪比的有效提升.     

基于智能手机平台的计算光学显微成像技术研究综述

计算光学显微成像技术将光学编码和计算解码相结合,通过光学操作和图像算法重建来恢复微观物体的多维信息,为显微成像技术突破传统成像能力提供了强大的助力。这项技术的发展得益于现代光学系统、图像传感器以及高性能数据处理设备的优化,同时也被先进的通信技术和设备的发展所赋能。智能手机平台作为高度集成化的电子设备,具有先进的图像传感器和高性能的处理器,可以采集光学系统的图像并运行图像处理算法,为计算光学显微成像技术的实现创造了全新的方式。进一步地,作为可移动通信终端,智能手机平台开放的操作系统和多样的无线网络接入方法,赋予了显微镜灵活智能化操控能力与丰富的显示和处理分析功能,可用于实现各种复杂环境下多样化的生物学检测应用。文中从四个方面综述了基于智能手机平台的计算光学显微成像技术,首先综述了智能手机平台作为光学成像器件的新型显微成像光路设计,接下来介绍了基于智能手机平台先进传感器的计算光学高通量显微成像技术,然后介绍了智能手机平台的数据处理能力和互联能力在计算显微成像中的应用,最后讨论了这项技术现存在的一些问题及解决方向。     

采用自适应模糊优化的目标跟踪加速方案

目标跟踪作为计算机视觉的重要方向之一,在自动驾驶、安防监控等方面有着广泛的应用,但是目标跟踪算法还无法有效地运行在嵌入式设备上。针对目标跟踪算法计算量大、复杂度高,难以部署在资源受限的嵌入式设备的问题,提出了一种基于相关滤波目标跟踪的加速方案。首先采用自适应模糊算法优化了跟踪算法整体运算量,它可以根据目标跟踪框的尺寸判定是否降低图像质量。其次采用了跟踪响应结果的峰值旁瓣比与平均相关能量比判据来评估跟踪结果的可信度,从而实现跟踪模型的自适应更新以及目标位置的重搜索。最后基于FPGA并行实现相关运算和跟踪检测器训练阶段的矩阵相乘运算,以提升算法实时能效性。所提出的加速算法基于PYNQ-Z2进行硬件测试,并在OTB-2015跟踪数据集上进行验证,该算法的跟踪精度与跟踪实时性分别为65.8%,17.28 frame/s,相比于原始算法,跟踪精度、跟踪实时分别提高了9.12%、703.7%。     

空间边缘计算:需求、架构及关键技术

随着航天电子技术的迅猛发展,特别是商用货架器件(COTS)的广泛使用,星载计算处理能力获得大幅跃升。空间边缘计算将广域分散的星载计算资源通过星间链路临机自组织成一个空间分布、计算协同的云环境,实现资源相助、任务协同,可以有效摆脱对地面的依赖、提升服务响应速度。该文首先从空间边缘计算的应用需求出发,梳理了空间边缘计算的发展现状以及存在的问题与挑战;然后在此基础上总结分析,提出一种空间边缘计算架构,并从物理架构、功能架构、软件架构以及服务流程等多维角度进行了阐述;最后对涉及的关键技术进行了概述和分析,以期能够为后续的研究提供有价值的建议和参考。     

Improved DV-Hop based on parallel and compact whale optimization algorithm for localization in wireless sensor networks

Wireless Networks - Improving localization performance is one of the critical issues in Wireless Sensor Networks (WSN). As a range-free localization algorithm, Distance Vector-Hop(DV-Hop) is...     

Origin and manifestation of the anharmonic potential felt by an ion-cloud in an actual Paul trap

The anharmonic potential felt by a single-species ions confined in a rf quadrupole trap which results from a non-ideal trap configuration and the charge distribution of the ion cloud is studied. The rf resonance-absorption spectra are explained by a Duffing oscillator and a representation of the line-shape parameter is derived. For > 0.77, the electric signals will exhibit hysteresis. The relation with the anharmonic potential is discussed.     

Finite-element analysis of planar dielectric waveguide discontinuities

The finite element method is combined with the mode-matching method and the multi-mode network method to analyze the scattering and radiation characteristics of a class of planar dielectric waveguide discontinuities. Unlike the conventional method to treat the radiation as a source-field problem, in the present approach, the dispersion characteristics of dielectric guided-wave structures are calculated first, and then the radiation problem is transferred to the propagation problem of a series of surface-waves and space waves from the viewpoint of scattering, thus the analysis is tremendously simplified.     

Foxby duality and Gorenstein injective and projective modules

In 1966, Auslander introduced the notion of the -dimension of a finitely generated module over a Cohen-Macaulay noetherian ring and found the basic properties of these dimensions. His results were valid over a local Cohen-Macaulay ring admitting a dualizing module (also see Auslander and Bridger (Mem. Amer. Math. Soc., vol. 94, 1969)). Enochs and Jenda attempted to dualize the notion of -dimensions. It seemed appropriate to call the modules with -dimension 0 Gorenstein projective, so the basic problem was to define Gorenstein injective modules. These were defined in Math. Z. 220 (1995), 611--633 and were shown to have properties predicted by Auslander's results. The way we define Gorenstein injective modules can be dualized, and so we can define Gorenstein projective modules (i.e. modules of -dimension 0) whether the modules are finitely generated or not. The investigation of these modules and also Gorenstein flat modules was continued by Enochs, Jenda, Xu and Torrecillas. However, to get good results it was necessary to take the base ring Gorenstein. H.-B. Foxby introduced a duality between two full subcategories in the category of modules over a local Cohen-Macaulay ring admitting a dualizing module. He proved that the finitely generated modules in one category are precisely those of finite -dimension. We extend this result to modules which are not necessarily finitely generated and also prove the dual result, i.e. we characterize the modules in the other class defined by Foxby. The basic result of this paper is that the two classes involved in Foxby's duality coincide with the classes of those modules having finite Gorenstein projective and those having finite Gorenstein injective dimensions. We note that this duality then allows us to extend many of our results to the original Auslander setting.