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。     

Assessment of reconfiguration schemes for Reconfigurable Manufacturing Systems based on resources and lead time

Reconfigurable manufacturing equipment is developed to meet the growing demand for more agile production. Agile manufacturing technology can improve the turnover of a company if it enables fast market introduction for volume production. Modular reconfiguration, defined as changing the structure of the machine, enables larger variation of products on a single manufacturing system; these solutions are called Reconfigurable Manufacturing Systems (RMS). The quality of RMS, and the required resources to bring it to reliable production, is largely determined by a swift execution of the reconfiguration process. This paper proposes a method to compare alternatives for the ways to implement reconfiguration. Three classes of reconfiguration are defined to distinguish the impact of the proposed alternatives. The procedure uses a recently introduced index method for development of RMS process modules, based on the Axiomatic Design methodology. Weighting factors are used to calculate the resources and lead time needed to implement the reconfiguration process. Application of the method leads to quick comparison of alternatives in the early stage of development. Successful execution of the method was demonstrated for the manufacturing process of a 3D measuring probe.     

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。     

Metrics to identify meaningful downscaling skill in WRF simulations of intense rainfall events

Dynamical downscaling attempts to provide regional detail to climate change projections that subsequently can be used as input to climate change impact models. However, unlike forecasts by numerical weather prediction models, downscaled projections cannot be tested for skill because the future of interest is decades away. Nevertheless, models can be tested in terms of how well they simulate current weather or climate, thus giving an indication of skill in representing the process of interest. Here, six configurations using different combinations of three microphysics and two planetary boundary layer schemes are assessed on their skill to simulate desired characteristics in daily rainfall fields from three two week simulations in southeast Australia; ‘desired’ meaning desirable in relation to the intended application. Of different metrics and analysis assessed, a metric based on variography analysis, summarising characteristics about spatial variability and dissimilarity, is shown to provide the most informative guidance relative to the desirable characteristics.     

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.     

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.     

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.     

基于RSA的可截取签名改进方案

在多方参与的签名环境中,可截取签名体制（CES）解决了信息的多次签名和多次传递等问题。对现有CES方案进行了分析,发现现有方案截取后的文档存在版式凌乱的缺陷。针对该缺陷,结合批签名思想,提出了一种基于RSA的可截取签名改进方案,并分析了截取者的各种行为对签名验证的影响?。研究表明,新方案在保持原方案安全性能不变的基础上,优化了截取文档的结构,提高了签名效率。     

对两种基于离散对数代理盲签名的分析

高炜等人和Yu Bao-zheng等人分别提出了两种基于离散对数的代理盲签名方案。对这两种方案进行了安全性分析。研究表明,这两种方案存在以下不足之处：高炜等人的代理盲签名方案是对谭等方案的改进,新的方案仍然具有可连接性,即代理签名者可以从一个合法的代理盲签名中恢复出此签名的中间值从而跟踪消息的拥有者。Yu Bao-zheng等人的代理盲签名方案同样具有可连接性的缺点。除此之外,用户可以通过自己持有的代理盲签名信息恢复出代理签名私钥,从而可以冒充代理签名者伪造消息m的代理盲签名或者直接利用一个合法的代理盲签名伪造出其它消息的合法代理盲签名。为了避免上述不足之处,给出了一个防止代理签名者连接性攻击的改进方案。     

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....     

Ordering of simultaneous events in distributed DEVS simulation

Simultaneous events are the events scheduled to occur at the same simulation time. This paper proposes a new event ordering mechanism for handling simultaneous events of DEVS models in distributed simulation. The DEVS formalism provides a formal framework for specifying discrete event models in a modular, hierarchical form. Thus, the formalism can ease the model verification and validation problems of distributed simulation. Also, the formalism separates models from underlying simulation algorithms. Hence, DEVS models can be simulated in both sequential and distributed environments without any modification. One important issue for such framework is to obtain the same results in both simulation environments. However, in distributed simulation of DEVS models, the processing order of simultaneous events may affect the simulation results. Thus, some ordering mechanism of events is required for well-defined simulation results. The proposed mechanism orders simultaneous events correctly with respect to their causal relationships in distributed DEVS simulation. Also, the mechanism guarantees the same ordering of simultaneous events in both sequential and distributed simulation environments.     

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.     

基于极限学习机的网页分类应用

极限学习机ELM不同于传统的神经网络学习算法（如BP算法）,是一种高效的单隐层前馈神经网络（SLFNs）学习算法。将极限学习机引入到中文网页分类任务中。对中文网页进行预处理,提取其特性信息,从而形成网页特征树,产生定长编码作为极限学习机的输入数据。实验结果表明该方法能够有效地分类网页。     

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.     

基于极端途径的生化网络模块化分析

近年来,对于复杂生化网络系统进行模块化分析引起了科研人员的极大关注。一般认为,模块化分析有助于理解这些网络的结构与功能关系。但是,当前的模块化分析方法大多将生化网络考虑为普通的复杂网络,所得模块的生物学意义较低。介绍了化学计量矩阵及极端途径分析等基本概念,对苏云金杆菌的丁醇代谢系统进行建模分析,研究结果表明：极端途径分析可用于识别网络中的功能模块,具备较好的生物学意义。     

基于多种偏好信息的物流方案评估方法

为了有效地反映物流方案评价中评价信息的模糊性,提出了基于多种偏好信息的物流方案评估方法。决策者采用各自偏好的信息形式对物流方案进行评价;利用转换函数将多种形式的偏好信息一致化为模糊互补判断矩阵,应用行和归一化方法计算排序向量,从而将决策成员的权重集结并获得物流方案的初始优先度;合成初始优先度与各项评价相应的修正系数,并通过规范化处理得到物流方案的优先度。通过一个实例验证所提方法。     

基于极端学习机的MANET移动性预测模型

针对移动自组织网络移动性在管理无线网络带宽资源可用性方面的重要性,为了更好地规划连续服务可用性和有效能源管理以提升网络的整体服务质量,提出了一种基于极端学习机的MANET移动性预测模型。利用ELM对MANET中的任意节点进行建模;假设已知每个移动节点当前的移动性信息（位置、速度和运动方向角度）,以这种方式预测节点未来的位置和相邻节点之间未来的距离;基于几个标准移动性模型,产生更加真实、精确的移动性预测,从而更好地捕捉任意节点直角坐标系之间现有交互/相关性。使用标准移动性模型的仿真结果验证了所提模型的有效性,实验结果表明,提出的预测模型明显改进了传统基于多层感知器的模型,此外,当预测相邻节点之间未来距离时,避免了当前算法对预测精度的限制。     

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。