EM框架下实现被动测距的状态估计和参数学习

在红外成像跟踪系统中,通常仅能测量目标的角度信息,不能直接测量目标与观测站间的距离。研究了基于红外成像系统的被动测距技术,首先利用状态空间模型的分析方法建立被动测距的状态估计和参数学习的混合估计模型,然后介绍EM的基本原理和参数的最大似然估计。EM算法的E步利用粒子滤波和粒子平滑器来完成,实现被动测距的状态估计;M步利用梯度搜索的方法来求解参数。被动测距是一个带有未知参数的非线性系统的状态估计,文中利用状态估计与参数学习的状态空间模型来描述,并利用EM法来求解,为被动测距的求解提供了一条新的途径。模拟实验表明,基于粒子滤波和梯度搜索的EM方法能同时完成被动测距的状态估计和参数学习。     

100 nm P型超浅结制作工艺研究

介绍了一种P型超浅结的制作工艺。该工艺通过F离子注入和快速热退火技术相结合,获得了比较先进的100nm以内的P型超浅结;重点研究了影响超浅结形成的沟道效应和瞬态增强扩散效应;详细介绍了制作过程中对沟道效应和瞬态增强扩散效应的抑制。     

维护军队电磁空间安全的对策思考

军队电磁空间事关军队战略安全,不仅是信息时代军队战斗力生成的重要支撑,而且是信息化条件下争夺战争主动权的焦点。当前,军队电磁空间主要面临着作战对手的信息攻击、己方信息系统的电磁冲突以及非传统安全领域威胁等多重威胁。维护军队电磁空间安全,要重点从强化军队人员的电磁空间安全意识、建立维护电磁空间安全的长效机制、发展电磁空间安全领域的关键技术、组织平战一致的信息防御行动等方面研究对策措施。     

基于电磁场原理的航天器变频吸振技术

为了有效抑制航天器转动部件对敏感载荷的扰动,将电磁技术应用于变频吸振器上,从经典电磁理论出发,建立了斥力悬浮型电磁变频装置的数学模型。该型电磁变频装置通过两个电磁铁对中间的永磁体产生排斥作用来产生恢复力:当中间永磁体偏离平衡位置时,由于两边电磁铁斥力的非线性变化使得二者对中间永磁体产生一个指向平衡位置的恢复力。理论分析表明,在气隙不大的情况下,该力与永磁体偏离平衡位置的位移成正比,同时其与电磁铁中通入的电流成正比关系,进一步的仿真也验证了该结论,这为有效、精确控制变频吸振器的工作频率提供了理论依据。根据理论计算和有限元仿真,采用了电磁技术的变频装置可以提供4 500 N/m左右的刚度变化范围,应用该变频装置的吸振器可以提供近50 Hz的频率变化范围,同时其调节速度和精度也能满足航天器对变频吸振器相关性能的要求。     

Robust depth map inpainting using superpixels and non-local Gauss–Markov random field prior

Depth maps contain 3D geometrical information of a scene which can be useful in many applications. In this work we address the task of inpainting a depth map afflicted by regions with missing data. Initially, we inpaint depth values missing at random locations as well as due to overlaid text. Subsequently, we propose an approach for filling large holes in the input depth map wherein superpixel division of the corresponding RGB image is also exploited. We use a non-local extension of the classical Gauss–Markov random field model for the completed depth map, so that missing information in the degraded observation can be estimated depending upon self-similarities between non-local patches inside a superpixel based search window. Several experiments performed with disparity maps and real world depth data exhibit the efficacy of the proposed algorithm.     

TD‐CFIE Formulation for Transient Electromagnetic Scattering from 3‐D Dielectric Objects

In this paper, we present a time domain combined field integral equation formulation (TD‐CFIE) to analyze the transient electromagnetic response from dielectric objects. The solution method is based on the method of moments which involves separate spatial and temporal testing procedures. A set of the RWG functions is used for spatial expansion of the equivalent electric and magnetic current densities, and a combination of RWG and its orthogonal component is used for spatial testing. The time domain unknowns are approximated by a set of orthonormal basis functions derived from the Laguerre polynomials. These basis functions are also used for temporal testing. Use of this temporal expansion function characterizing the time variable makes it possible to handle the time derivative terms in the integral equation and decouples the space‐time continuum in an analytic fashion. Numerical results computed by the proposed formulation are compared with the solutions of the frequency domain combined field integral equation.     

一种基于车载MP3播放机的倒车雷达设计

提出了一种基于车载MP3播放机-SH252的倒车雷达设计方案,并介绍了系统的软硬件设计思路。系统采用EM78P153单片机作为倒车雷达数据采集部分,采用超声波探测方式测距。在倒车时,倒车雷达会自动启动,并在EM78P153的控制下,由装置于车尾保险杠上的探头发送超声波信号,当遇到障碍物时,产生回波信号,探头接收到回波信号后经控制器进行数据处理并计算出车体与障碍物之间的实际距离,然后将数据发送到车载MP3播放机上进行距离显示和语音同步提示,为驾驶员提供报警提示,提高驾驶的安全性。     

基于EM78P419N单片机的消毒烘干机的设计

为了改善传统烘干机烘手时间长、易交叉感染、可靠性低等问题,进行了消毒干手机的设计。该设计利用红外技术检测信号,再将光信号转换成电信号送入EM78P419N单片机,通过单片机的处理后,启动电磁阀和滴水泵进行消毒。定时完成后,启动加热器和风扇进行烘干。整个过程完全自动控制,避免了交叉感染,手伸即喷,手离即停。同时,研制出的样品具有成本低、体积小、可靠性高、干手时间短等优点,在各类人员聚集或流动的场所应用广泛。     

Markovian场中四能级系统的窄带五阶非线性效应

本文采用高阶相干函数理论研究了四能级系统在Markovian场下的窄带五阶非线性效应（NFPBFMS）。我们得到了混沌场模型、相散场模型及实高斯场模型下窄带拍频信号强度随时间的变化规律，并讨论了三种模型对测量原子能级分裂精度的影响。     

Application of Green's functions for analysis of transient thermal states in electronic circuits

This paper presents an approach to the modelling of transient thermal states in electronic circuits using an analytical solution of the heat equation. Fully three-dimensional analytical time dependent solutions are determined with the help of Green's functions. The solution method is illustrated in detail on a practical example, where the results of transient thermal simulations of a real hybrid circuit are compared with infrared measurements.