基于神经网络的微波均衡器建模与仿真

采用 RBF 神经网络对微波均衡器进行建模,并应用到微波均衡器的分析与设计中。由于神经网络具有精度高、实时调用速度快等优点,因此建立的微波均衡器神经网络设计方法具有准确、可靠、省时、辅助设计等优点。仿真结果证明了该方法在微波均衡器分析设计中的有效性。     

基于PID控制LLC微波电源的仿真研究

研制了一款基于PID控制输出电压的高频软开关电源。主电路采用了倍压整流输出LLC谐振变换器,利用PID控制闭环电压反馈,并通过对谐振变换器的特性分析绘制了直流增益曲线。根据理论分析与计算并结合实际调试情况,对LLC微波电源的主要参数进行设计,得到的仿真实验结果验证了分析计算的正确性。     

基于三维仿真技术的降水现象仪视频课件开发

采用三维仿真技术,开发气象观测业务改革调整后的降水现象仪装备保障视频课件.根据降水现象仪视频课件教学内容,利用三维仿真技术,设计降水现象仪视频课件三维动画呈现形式降水现象仪视频课件开发的完成及其推广应用,丰富了气象装备保障学习资源库,提升了气象教育培训教学效果.     

MERADGEN 1.0: Monte Carlo generator for the simulation of radiative events in parity conserving doubly-polarized Møller scattering

The Monte Carlo generator MERADGEN 1.0 for the simulation of radiative events in parity conserving doubly-polarized Møller scattering has been developed. Analytical integration wherever it is possible provides rather fast and accurate generation. Some numerical tests and histograms are presented.

Program summary

Program title: MERADGEN 1.0Catalogue identifier:ADYM_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADYM_v1_0Program obtainable from: CPC Program Library, Queen's University of Belfast, N. IrelandLicensing provisions: noneProgramming language: FORTRAN 77Computer(s) for which the program has been designed: allOperating system(s) for which the program has been designed: LinuxRAM required to execute with typical data: 1 MBNo. of lines in distributed program, including test data, etc.:2196No. of bytes in distributed program, including test data, etc.:23 501Distribution format:tar.gzHas the code been vectorized or parallelized?: noNumber of processors used: 1Supplementary material: noneExternal routines/libraries used: noneCPC Program Library subprograms used: noneNature of problem: Simulation of radiative events in parity conserving doubly-polarized Møller scattering.Solution method: Monte Carlo method for simulation within QED, analytical integration wherever it is possible that provides rather fast and accurate generation.Restrictions: noneUnusual features: noneAdditional comments: noneRunning time: The simulation of 10⁸ radiative events for itest:=1 takes up to 45 seconds on AMD Athlon 2.80 GHz processor.     

Dual nature of events in discrete simulation

The problem caused by the representation of different types of events in discrete simulation is discussed and a solution based on their dual nature is presented.     

Design of vehicle certification schemes in IoV based on blockchain

World Wide Web - Because of a large number of vehicles in Internet of Vehicle(IoV), distributed nodes and complex driving environment, data security and certification speed are easily affected....     

Some filing schemes based on finite groups of automorphisms

From some families of partialt-designs which have automorphism groups of high transitivity new algebro-algorithmical filing systems permittingt-queries are constructed. Due to the computational properties of the groups used, new bounds for the retrieval times are obtained in several cases.     

The physical,radiative and microwave scattering characteristics of melt ponds on Arctic landfast sea ice

Melt ponds are an important characteristic of Arctic sea ice because of their control on the surface radiation balance. Little is known about the physical nature of these features and to date there is no operational method for detection of their formation or estimation of their aerial fraction. Coincident in situ observations, aerial surveys and synthetic aperture radar data from a field site in Arctic Canada are compared in an evaluation of the physical, radiative and electrical properties of melt ponds on first-year and multiyear sea ice. Results show that the interrelationships between the thermal diffusivity and conductivity of the snow cover control the mechanisms of snow ablation. Aerial fractions of snow patches, and light and dark coloured melt ponds, show considerable variation both as a function of proximity to land and due to ice type. First-year sea ice is shown to have a water background with discrete snow patches distributed throughout. Multiyear sea ice consists of discrete 'particles' within a snow background. Morphological measurements indicate that snow patches range in size with average areas of from 5 to 20m2 . Pond sizes over multiyear sea ice are also highly variable with averages ranging from 15 to 20m2. The integrated shortwave albedo was measured in the field and averaged to: snow patches (0.64 0.07); light melt ponds (0.29 0.04); and dark melt ponds (0.14 0.03). Snow patch size statistics explained a statistically significant proportion of the surface shortwave albedo. We found that microwave scattering could be used to obtain a measure of the onset ofmelt and had utility in detecting subtle details ofthe thermodynamic transition from winter through early melt into pond formation. We formalized a statistical relationship between microwave scattering and surface climatological albedo (sigma-alpha relationship). We found the relationship valid only for landfast firstyear sea ice under windy conditions. We conclude with a discussion of the role of surface wind stress and diurnal cycling in specification of the sigma-alpha relationship.     

Sidelobe reduction based on spectrum reshaping in microwave imaging

Sidelobe artifacts are a common problem in image reconstruction from finite-extent Fourier data obtained by microwave imaging system.In order to enhance the image quality,sidelobe reduction must be implemented.Taking the sidelobe reduction in microwave imaging as the research subject,this paper presents Fourier imaging technique firstly.Then the point spread function is obtained through Fourier inversion of rectangular spectral support data and the changing effect of sidelobe direction due to reshaping spec...     

基于STBC与V-BALST的虚拟MIMO方案研究

提出了一种比较不同编码速率的方法,并使用此方法分析了不同节点下基于V-BLAST和STBC两种虚拟MIMO方案的性能,得出了虚拟MIMO方案选择的一些结论。采用理论分析与Mento Carlo仿真相结合的方法,仿真结果为虚拟MIMO方案选择提供了理论依据,这对加速无线传感网的发展与应用无疑有重要意义。     

基于认知系统的编码调制体系研究

利用NMSK(N重最小频移键控)的旁瓣快速衰减特性,提出了一种新型OFDM-NMSK编码调制体系用于降低OFDM认知无线电系统的带外干扰.该方法仅通过关闭干扰频段上的相应NMSK子载波,能够快速生成符合要求的频谱凹槽深度,从而实现与其地窄带系统的共存.理论与仿真表明,与传统的相邻频带编码( AFC)方法相比,OFDM-NMSK编码效果更佳.     

基于Hash函数的秘密共享方案安全研究

分析了当前几种秘密共享方案的不足,且给出了一个基于单向Hash函数的动态秘密共享方案的改进算法,它的特性如下：更新系统密钥时,无须更改每个子密钥;当某个子密钥泄密时,不对其它子密钥的安全构成威胁;系统为新共享者分配子密钥时,其它子密钥不受任何影响;子密钥可无限制地多次使用;具有很强的防欺诈和欺诈识别功能,该算法已在计算机上进行模拟,该文将给出一些实验数据,并对算法性能进行分析。     

基于事件的主动队列管理研究

针对随机早期检测RED存在的对参数过于敏感、时延抖动、队长不稳定等问题,采用特殊事件标记法,通过调整丢弃概率的增减幅度,对RED算法进行了改进。实验表明,改进的算法在稳定性、链路利用率方面有了较好的改善。     

Development of a nanostructural microwave probe based on GaAs

In order to develop a new structural microwave probe, we studied the fabrication of an AFM probe on a GaAs wafer. A waveguide was introduced by evaporating Au film on the top and bottom surfaces of the GaAs AFM probe where a tip 7 μm high with a 2.0 aspect ratio was formed and the dimensions of the cantilever were 250 × 30 × 15 μm. The open structure of the waveguide at the tip of the probe was obtained by FIB fabrication. An AFM image and profile analysis for a standard sample, obtained by the fabricated GaAs microwave probe and a commercial Si AFM probe, indicate that the fabricated probe has a similar capability for measurement of material topography as compared to the commercial probe.     

Human face recognition based on ensemble of polyharmonic extreme learning machine

This paper proposes a classifier named ensemble of polyharmonic extreme learning machine, whose part weights are randomly assigned, and it is harmonic between the feedforward neural network and polynomial. The proposed classifier provides a method for human face recognition integrating fast discrete curvelet transform (FDCT) with 2-dimension principal component analysis (2DPCA). FDCT is taken to be a feature extractor to obtain facial features, and then these features are dimensionality reduced by 2DPCA to decrease the computational complexity before they are input to the classifier. Comparison experiments of the proposed method with some other state-of-the-art approaches for human face recognition have been carried out on five well-known face databases, and the experimental results show that the proposed method can achieve higher recognition rate.     

Three schemes of remote information concentration based on ancilla-free phase-covariant telecloning

In this paper, remote information concentration is investigated which is the reverse process of the $1\rightarrow 3$ optimal asymmetric economical phase-covariant telecloning (OAEPCT). The OAEPCT is different from the reverse process of optimal universal telecloning. It is shown that the quantum information via $1\rightarrow 3$ OAEPCT procedure can be remotely concentrated back to a single qubit with a certain probability via several quantum channels. In these schemes, we adopt Bell measurement to measure the joint systems and use projected measurement and positive operator-valued measure to recover the original quantum state. The results shows non-maximally entangled quantum resource can be applied to information concentration.     

基于表观BRDF的泡沫金属辐射特性反演测量方法

泡沫金属是通过在金属基体上形成大量孔隙结构而得到的一类新型多功能材料,在太阳能利用、强化换热等领域有重要应用价值,其辐射特性参数是分析其内部辐射传递的必要物性数据。提出一种基于表观双向反射分布函数（ BRDF）测量数据反演泡沫金属热辐射物性的方法,利用测量的多角度入射的表观BRDF数据结合辐射传递方程求解来反演泡沫金属的等效辐射特性。对泡沫铁镍（50 ppi ）、泡沫铜（90 ppi）及泡沫镍（30 ppi）三种泡沫金属样品在波长660 nm激光照射下1/2半球空间的表观BRDF分布进行了实验测量,并对其辐射特性进行了反演,首次获得了这三种材料的辐射特性参数,其辐射物性表现出明显的半透明性质,散射反照率随着孔隙数密度的增加而增加,散射相函数呈后向散射占优。     

基于OSG粒子系统的雪景模拟

为了模拟真实降雪场景,建立逼真的雪景仿真系统,提出了一种基于OSG (open scene graph)粒子系统的仿真模拟技术,建立以雪粒子受力情况分析为核心的自定义雪粒子模型.该模型分析了雪粒子的具体受力情况,随机确定雪粒子的各初始属性,并在每帧中动态的赋予雪粒子不同的风力值以模拟真实降雪场景中的风力情况,解决了传统模型中雪粒子受力不够真实的情况.实验结果表明,自定义雪粒子模型能够更加真实的模拟降雪场景,具有逼真的仿真效果.