牵引供电设备巡视监控系统设计

根据当前国内电气化铁路对牵引供电系统的安全可靠运行的要求,结合保定电务段的实际情况设计了一套供电设备巡视监控系统,本文介绍了该系统的系统结构及其基本组成单元,对信息的采集、传输及处理进行了分析.     

基于模型的开发方法在通讯管理模块软件中的应用

本文介绍了Harmony的基于模型的嵌入式软件开发方法,并采用该方法对综合数据管理系统中的通讯管理模块应用软件进行了软件实现。介绍了通讯管理模块所应完成的功能,阐述了采用基于模型的开发方法所设计的类及其功能,也描述了这些类的关系以及状态图。最后阐述了Rhapsody根据模型自动生成代码和可执行文件的方法。     

一种融合指纹信息的二维码智能锁设计

针对传统锁具安全系数低、识别困难、远程解锁困难等缺点,基于51单片机设计了一款二维码智能锁.智能锁集指纹采集、二维码生成、扫描开锁于一体,由锁体和二维码生成软件两部分组成,由上位机采集用户指纹信息生成二维码钥匙,并将获取的二维码信息发送至锁体,当用户开锁时由锁体将两者信息进行比对实现开锁.实验表明,智能锁一定程度上满足了多种应用场景下的用户身份认证需求,具有较高的应用推广价值.     

Abnormal Shape Mould Winding

为解决网格化芯模的缠绕问题,本文提出了复合材料面片缠绕机理;接着详细分析了面片缠绕过程中的芯模凹曲面上纤维滑线和架空现象,应用微分几何曲面理论和空间几何理论,提出判据及其解决方案;最后,针对飞机发动机进气道的缠绕成型,编制缠绕控制程序并进行相应的实验,验证了面片缠绕方法的可行性。     

无源互调对直扩系统伪码捕获性能的影响

无源互调干扰信号会对无线通信系统造成不同程度的影响,轻则干扰无线通信系统,严重时阻塞无线通信系统信号传输通道。为了定量分析无源互调干扰信号对直扩系统伪码捕获性能的影响,建立了无源互调干扰下直扩系统模型,考虑卫星接收机中噪声的影响,采用修正柯西分布概率密度模型,分别对平方律检波器捕获方法和平方检波累积器捕获方法在无源互调干扰下的捕获性能进行了理论推导和仿真验证。仿真结果表明,高信干噪比下无源互调干扰对通信系统的影响比噪声小,90%捕获检测概率下相差2.92dB;采用平方检波累积方法可获得一定的累积增益,90%捕获检测概率下的累积增益为2.36dB。     

基于半无码的P(Y)码自相关GNSS-R海面测高方法

针对传统GPS C/A码延迟测高方法测高精度低和互相关测高方法时延波形信噪比低的问题,研究了基于半无码的P（Y）码自相关海面测高方法。首先,通过理论测高精度模型,对比分析了C/A码和P（Y）码的测高精度;然后,描述了L1、L2双频反射信号基于半无码的P（Y）码自相关处理架构,并论述了测高模型和L1、L2双频电离层时延误差修正方法;最后,利用模拟的L1、L2反射信号对比分析了基于半无码的P（Y）码自相关、C/A码自相关以及信号互相关方法的海面测高精度。结果表明:相比于C/A码自相关和信号互相关测高精度,基于半无码的P（Y）码自相关的测高精度分别提高了3.97倍和1.47倍。      

基于CCSDS的低码率图像压缩优化算法

为了提高空间数据系统咨询委员会（CCSDS）采用的图像压缩算法的编码效率,提出了一种二维预测模型。通过利用图像像素之间的空间相关性对直流系数的预测模式及其熵编码算法进行改进和优化,该算法在有效地提高了直流系数的压缩比的同时,也增强了其抗误码性能。试验结果表明,该算法在低码率条件下能获得更好的图像编码质量,与CCSDS原有算法相比,峰值信噪比值提高了0.1~0.3dB。算法可极大地满足星载图像压缩数据在低码率下传输的要求。     

基于文本编码分割的医学影像文本水印算法

针对已有文本水印嵌入算法中所采用的二进制数据流描述文本水印时所表达的信息有限、水印容量较小的问题,提出了一种基于文本编码分割的医学影像文本水印算法,通过二维离散小波变换对医学影像的不同层次进行分解,将编码分割处理后的文本水印嵌入到小波分解的三级低频部分,实现了文本水印的隐秘嵌入。实验结果表明,该算法可提高医学影像文本水印容量2-3倍。     

飞机研发中的精益设计与敏捷管理

本文针对传统飞机设计和研发管理方面存在的问题,提出了精益设计与敏捷管理的观点。首先对精益设计与敏捷管理的内涵和关系进行概述;然后从飞机研制中的物理设计和试验,系统、软件设计和试验,多学科优化设计,产品数据管理,协同设计等方面提出了提高飞机精益设计的主要手段;从战略、组织、技术、管理、文化等方面阐述了提高敏捷管理的主要做法;最后以研究所为例,概要阐述了精益设计与敏捷管理的应用及实施效果。     

An update about recent developments of the PHITS code

PHITS (Particle and Heavy-Ion Transport code System) is a general-purpose three-dimensional Monte Carlo code, developed and maintained by RIST, JAEA and KEK in Japan together with Sihver et al. at Chalmers in Sweden. PHITS can deal with the transports of all varieties of hadrons and heavy ions with energies up to around 100 GeV/nucleon, and in this paper the current status of PHITS is presented. We introduce a relativistically covariant version of JQMD, called R-JQMD, that features an improved ground state initialization algorithm, and we will present the introduction of electron and photon transport in PHITS using EGS5, which have increased the energy region for the photon and energy transport from up to around 3 GeV to up to several hundred GeV depending on the atomic number of the target. We show how the accuracy in dose and fluence calculations can be improved by using tabulated cross sections. Benchmarking of shielding and irradiation effects of high energy protons in different materials relevant for shielding of accelerator facilities is also presented. In particular, we show that PHITS can be used for estimating the dose received by aircrews and personnel in space. In recent years, many countries have issued regulations or recommendations to set annual dose limitations for aircrews. Since estimation of cosmic-ray spectra in the atmosphere is an essential issue for the evaluation of aviation doses, we have calculated these spectra using PHITS. The accuracy of the atmospheric propagation simulation of cosmic-ray performed by PHITS has been well verified by experimental cosmic-ray spectra taken under various conditions. Based on a comprehensive analysis of the simulation results, an analytical model called “PARMA” has been proposed for instantaneously estimating the atmospheric cosmic-ray spectra below the altitude of 20 km. We have also performed preliminary simulations of long-term dose distribution measurements at the ISS performed with the joint ESA-FSA experiment MATROSHKA-R (MTR-R) led by the Russian Federation Institute of Biomedical Problems (IMBP) and the ESA supported experiment MATROSHKA (MTR), led by the German Aerospace Center (DLR). For the purpose of examining the applicability of PHITS to the shielding design in space, the absorbed doses in a tissue equivalent water phantom inside an imaginary space vessel has been estimated for different shielding materials of different thicknesses. The results confirm previous results which indicate that PHITS is a suitable tool when performing shielding design studies of spacecrafts.