光电成像系统的协同设计方法研究（英文）

在传统的光电成像系统设计中,光学子系统和电子学子系统是分开设计的.这导致两个子系统的参数化之间协调程度降低,导致子系统兼容性不完善.为了提高各子系统之间的兼容性,缩短设计时间,减少开发成本,本文提出了一种协同设计方法.在端到端光电性能评价的基础上,采用多目标多参数优化算法对光电成像系统的配置参数进行优化.利用该方法对空间红外成像系统配置参数进行了优化,且获得良好在轨成像效果.结果表明,该方法对优化光电成像系统的参数配置,评价光电成像系统的性能具有积极的作用.     

基于信息理论的成像系统干扰效果评估

把信息熵应用于成像系统中,用端到端的互信息评价图像成像系统,研究成像系统的干扰设计方法.模拟系统设计参数,计算机仿真分析了三种性质的干扰对成像系统的影响,做出了基于互信息量的干扰效果仿真曲线.这对于光电对抗装备的研制、开发和效能评估具有一定的参考价值.     

机载光电成像系统电磁兼容性设计

为了提高机载光电成像系统抗电磁干扰能力,使其能适应复杂的战场电磁环境,对机载光电成像系统进行了电磁兼容性设计。采用屏蔽、滤波、接地等技术措施对系统中易产生或引起干扰的部位进行了电磁兼容性设计,并对电源线传导发射和电场辐射发射两项最容易超标的项目进行了测试试验。实验结果表明,机载光电成像系统经过电磁兼容性设计后,其电源线传导发射值降低了35 dBμV 以上,电场辐射发射的辐射值降低了约27 dBμV ／m,并且有较大的裕量。满足机载光电成像系统在复杂战场电磁环境下使用的要求。     

一种改进的CNN端到端自编码器通信系统

针对现有端到端神经网络通信系统的泛化能力改进及自编码器优化等问题,提出了一种基于卷积神经网络(Convolutional Neural Network,CNN)的端到端通信系统改进方案。该方案在自编码器结构中引入一维卷积层(Conv1D),通过对参数的重新设计,优化了网络性能。发送端采用多层Conv1D对输入序列进行特征提取,通过训练获得发送信号的最佳调制和编码方案;接收端同样采用多层Conv1D,来恢复受到噪声污染的符号。仿真实验表明,在不同输入比特长度及编码速率条件下,所提系统表现出了良好的泛化能力。并且,在加性高斯白噪声信道和瑞利衰落信道下,训练模型的误码性能与传统的调制方式性能相吻合,验证了系统方案的可行性和有效性。此外,对于数字传输常见的突发信道,所提方案具有良好的适应性,可获得1 dB左右误码性能的改善。     

基于MRTD信道宽度的热成像系统性能评价理论研究

热成像系统与人眼之间存在最佳匹配问题,存在一个最佳的角放大率使人眼与成像系统达到最佳的匹配状态,使系统性能达到最佳.本文提出一种基于信噪比模型的热成像系统性能评价方法,导出了一个基于MRTD信道宽度的热成像系统评价参量.通过对实际热成像系统的观察实验和分析比较,表明使用这个评价参量,可以获得热成像系统的最佳角放大率或最佳观察距离,使系统与人眼视觉得到最佳的匹配状态.结果对于进一步发展光电成像系统的性能评价理论具有理论意义,而且可望对实际系统的设计提供理论指导.     

基于编码成像的激光能量调控方法研究

为了有效提升光电成像系统焦平面探测器在外界存在激光干扰条件下的环境适应性,同时不显著降低原成像系统成像性能,提出了一种基于编码成像的激光能量调控方法,构建了一套以液晶空间光调制器为核心器件的编码成像实验系统并对该系统的成像性能进行了测试,设计了一套基于编码成像的激光能量调控实验验证系统并开展了多参数条件下编码成像抗激光干扰实验研究。实验结果表明,基于编码成像的激光能量调控方法可在不显著降低成像质量前提下有效提升焦平面探测器的抗激光干扰性能。     

耦合式背光介观荧光分子成像系统设计北大核心CSCD

在生物组织工程的应用中需要有对生物结构标记的三维、纵向评估。一般来说,这些生物组织的结构通常是几毫米厚和浑浊的,因此对图像成像有很大挑战性,且经典荧光显微技术不能满足于其需要。介观荧光分子成像系统是一种新兴的成像系统,该系统基于介观荧光分子层析方法,它填补了显微荧光分子成像技术和宏观荧光分子成像技术之间的空白。为提升介观荧光分子重建的性能,本文主要基于光学原理对光学系统的配置参数进行了优化和改进,包括探测器布局、非耦合或耦合的扫描模式,并对介观荧光分子成像系统的三维成像性能进行了评价和对比。结果表明,本文设计的耦合式背光介观荧光分子层析成像(mesoscopic fluorescence molecular tomography imaging,MFMT)系统能够很好地提升重建性能,获得高质量的重建结果。     

基于信息理论的采样成像系统优化设计方法

本文把信息论应用于采样成像系统中，用端到端的互信息量评价图像捕捉系统，研究光电一体化系统优化设计方法。模拟系统设计参数，计算机仿真分析了采样成像系统中普遍存在的欠采样噪声、光学成像系统的模糊效应以及二者之间的涨落、平衡，做出了基于互信息量的系统评价仿真曲线，提出了光学成像系统与图像捕捉系统的匹配条件和优化设计方法。     

基于SSA ELM和自适应差分进化算法的拉曼放大器设计北大核心CSCD

提出了一种将樽海鞘群算法优化极限学习机与自适应差分进化算法相结合的方法,并利用该方法优化多泵浦拉曼光纤放大器的参数配置。采用极限学习机构建泵浦参数和拉曼增益之间的非线性映射,并利用樽海鞘群优化算法对极限学习机参数进行优化获得最佳模型。对比分析了上述模型与BP神经网络和传统的极限学习机模型在评价指标方面的差异,结果表明本文所提出的模型预测性能较好。为了提高增益平坦性,利用自适应差分进化算法优化泵浦参数,得到最佳的参数配置。仿真结果表明,利用该方法设计出的拉曼放大器达到了预期效果,其目标增益与预测增益的最大误差不超过05dB。该方法为今后拉曼光纤放大器的设计提供了一种新的思路方法。     

时间触发总线时间同步和端到端时延测试方法

分析了TTP总线时间同步机制和基于中断方式的端到端数据传输模式,以及节点间时间同步、端到端时延和抖动等参数,设计了同步精度和时延测试方法,构建测试原型系统和配置场景并开发测试用例。结果表明,各节点间的时间偏差小于总线配置场景所允许的同步精度上限5us,端到端时延263.30～267.43us。因时间槽设置为250us,可知主机应用层与总线控制器同步方式下数据传输的端到端时延主要取决于时间槽所占时间。此测试方法和所用的原型系统可用于TTP总线通信系统设计和部署的优化。     

Overrun Methods and Resource Holding Times for Hierarchical Scheduling of Semi-Independent Real-Time Systems

The Hierarchical Scheduling Framework (HSF) has been introduced as a design-time framework to enable compositional schedulability analysis of embedded software systems with real-time properties. In this paper, a software system consists of a number of semi-independent components called subsystems. Subsystems are developed independently and later integrated to form a system. To support this design process, in the paper, the proposed methods allow non-intrusive configuration and tuning of subsystem timing-behavior via subsystem interfaces for selecting scheduling parameters.      

Tuning hydrostatic two-output drive-train controllers using reinforcement learning

When controlling a complex system consisting of several subsystems, a simple divide and conquer approach is to design a controller for each system separately. However, this does not necessarily result in a good overall control behavior. Especially when there are strong interactions between the subsystems, the selfish behavior of one controller might deteriorate the performance of the other subsystems. An alternative approach is to design a global controller for the entire mechatronic system. Such a design procedure might result in more optimal behavior, however it requires a lot more effort, especially when the interactions between the different subsystems cannot be modeled exactly or if the number of parameters is large.In this paper we present a hybrid approach to this problem that overcomes the problems encountered when using several independent subsystems. Starting from such a system with individual subsystem controllers, we add a global layer which uses reinforcement learning to simultaneously tune the lower level controllers. While each subsystem still has its own individual controller, the reinforcement learning layer is used to tune these controllers in order to optimize global system behavior. This mitigates both the problem of subsystems behaving selfishly without the added complexity of designing a global controller for the entire system. Our approach is validated on a hydrostatic drive train.     

Modeling and maximizing burn-in effectiveness

System burn-in can get rid of many residual defects left from component and subsystem burn-in since incompatibility exists not only among components but also among different subsystems and at the system level. Even if system, subsystem, and component burn-in are performed, the system reliability often does not achieve the requirement. In this case, redundancy is a good way to increase system reliability when improving component reliability is expensive. This paper proposes a nonlinear model to: estimate the optimal burn-in times for all levels, and determine the optimal amount of redundancy for each subsystem. For illustration, a bridge system configuration is considered; however, the model can be easily applied to other system configurations. Since there are few studies on system, subsystem, and component incompatibility, reasonable values are assigned for the compatibility factors at each level     

区域超声影像远程会诊网络平台的构建及质量控制

远程医学会诊网络系统基本包括3大系统：远程疑难病会诊系统，远程影像学会诊系统及远程病理学会诊系统。本文重点论述远程影像学会诊系统——超声影像远程会诊网络平台的设计、构建实施及会诊质量控制。     

两轴四环架光电平台的多变量H∞控制方法

高精度光电稳定平台采用两轴四环架的结构形式扩展其跟踪范围,但增加了环架闻的耦合和系统的复杂度.提高稳定精度是控制系统设计的核心指标.以平台系统的动力学方程为基础,导出状态空间模型.针对内、外环架间的耦合特性,提出将内、外环架分系统作为多入多出对象进行多变量控制设计.采用H∞控制设计方法,根据平台系统对稳定性能和随动性能...     

Capacity analysis of spectrally overlaid macro/microcellular CDMA systems supporting multiple types of traffic

The reverse link capacity of a spectrally overlaid macrocell/microcell cellular code-division multiple-access system supporting various types of traffic is analyzed. Several narrowband subsystems are overlaid with a wideband subsystem in macrocells, while in a microcell, a single narrowband subsystem is operated with the same spectrum as one of the macrocell narrowband subsystems. Using a typical propagation model, the reverse link signal power and interference are characterized as the relative user signal power and the cross-tier interference factors between the macrocell and the microcell, considering various system parameters. The reverse link capacity of the overlay system is then analyzed. Results show that the dominant parameters affecting the system performance are the spectral overlay ratio and the distance between the microcell and macrocell base stations. In particular, when the distance equals half of the macrocell radius, optimum performance can be achieved by minimizing the cross-tier interference factors. These results can be applied to network planning for future wireless communication services.     

雷达电源系统技术发展现状

雷达电源系统承担为雷达其他各组成分系统提供电能的任务,处于最为基础的地位。雷达电源系统随着雷达功率的提高、雷达载体平台装备的增多而不断发展,变得日益复杂,面临着兼容性、稳定性等问题。雷达电源系统的设计目标是为雷达提供稳定可靠、性能优越、性价比高的电源系统。文中阐述了电源系统技术的概念,简述了当前雷达电源系统技术发展现状,讨论了雷达电源系统技术的发展趋势,总结了雷达电源系统的发展路径。     

Integrated design methodology of ball-screw driven servomechanisms with discrete controllers. Part II: Formulation and synthesis of the integrated design

In order to acquire high-speed and high-precision performances in ball-screw driven servomechanisms, an integrated design methodology has been proposed. Based on strict mathematical modeling and analysis of servomechanism performance according to design and operating parameters, a nonlinear constrained optimization problem including the relevant subsystem parameters of a ball-screw driven servomechanism is formulated. A multi-objective function and nondimensional variables are introduced in the design process. Constraints for the mechanical and control subsystems render the integrated design problem accurate. Optimum design results of the mechanical and control subsystems are obtained according to the design parameters specified by designers through the integrated design process. Motors are optimally selected from the servo motor database according to the iteration process. Both geometric errors due to Abbe offset and contour errors are minimized while required constraints such as stability and saturated conditions are satisfied. This design methodology not only optimizes the dynamic performance of the servomechanism, but also improves quality of the design process to achieve the required performance for ball-screw driven servomechanisms.     

Subsystem backstepping design for controlling a class of nonlinear SISO systems with cascade structure

This paper presents a controller design, referred to as the subsystem backstepping design (SSBD), for a class of nonlinear SISO mechatronic systems that comprise several cascaded subsystems. Compared with the conventional integrator backstepping design (CIBD) that deals with a first-order equation at each design step, the SSBD manages at each design step a subsystem that can be of high order. This both simplifies the design procedure and also makes controller parameters conveniently determined according to dynamic characteristics of each subsystem as in the conventional cascade control design with multiple feedback loops. However, in contrast to the conventional cascade control design, the SSBD does not require the inner feedback loop to respond much faster than the outer feedback loop, while guaranteeing system stability for a class of nonlinear systems. In addition, a variant of the SSBD, called internal model principle-based SSBD (IMP-SSBD), is presented to both further demonstrate the advantages of the SSBD procedure over the CIBD and also achieve robust tracking performance. The effectiveness of the proposed scheme is demonstrated through experimental studies of a harmonic drive system suffering from transmission compliance and periodic disturbances.     

光电探测技术在火控系统中的应用及发展

针对新型光电火控系统的应用和发展,结合光电探测技术在火控系统中的具体应用,对配备了光电传感器(激光测距、电视跟踪、红外跟踪)的新型光电火控系统的特点进行了分析。并以洛克希德.马丁公司为美国海军陆战队的AH-1Z"眼镜蛇"直升机研制的光电火控目标瞄准系统(TSS)为例,对目前世界上先进的多传感器火控系统的主要性能参数和功能特性进行了分析,并初步探讨了新型光电火控系统的发展趋势,即光电火控系统正朝着各光电系统光轴合一、功能多样化、多目标跟踪的方向发展。新型光电火控系统将进一步提高目标识别、定位距离和装备平台的存活能力。