基于ProModel的实心半轴生产线平衡仿真研究

在竞争日益激烈的汽车零部件市场,我国汽车零部件的竞争力仍然较弱。本文针对某实心半轴公司的生产线,进行生产线平衡的分析和研究,并利用ProM odel仿真软件对其生产线进行仿真,在逐步改善系统的最后提出一个可靠的优化方案。通过最经济的方式提高某实心半轴公司在汽车零部件市场上的竞争力。     

新的基于机器学习的入侵检测方法

提出了一种基于机器学习的用户行为异常检测方法,主要用于UNIX平台上以shell命令为审计数据的入侵检测系统。该方法在LaneT等人提出的检测方法的基础上,改进了对用户行为模式和行为轮廓的表示方式,在检测中以行为模式所对应的命令序列为单位进行相似度赋值;在对相似度流进行平滑时,引入了“可变窗长度”的概念,并联合采用多个判决门限对被监测用户的行为进行判决。实验表明,该方法在检测准确度和实时性上均优于LaneT等人提出的方法。     

基于Rough Set理论的综合分类器设计与实现

在入侵检测系统中为了降低神经网络结构的复杂性和网络计算负担,提高学习和收敛速度,将综合分类器分解为由一些单一功能的基础分类器组成,从而将复杂多变的攻击任务分解为针对不同服务的简单攻击;采用Rough Set约简理论,对该综合分类器的输入和隐含层节点进行优化,在保证信息完整性下减少网络节点.使用Matlab和VC++程序设计语言实现了此设计,并给出了实现的关键算法.通过实验验证,取得了一定成效.     

一种基于新型寄存器结构的逐次逼近A/D转换器

介绍了一种10位CMOS逐次逼近型A/D转换器。在25 kSPS采样频率以下,根据模拟输入端输入的0~10 V模拟信号,通过逐次逼近逻辑,将其转化为10位无极性数字码。转换器的SAR寄存器结构采用了一种新的结构来实现D触发器。该转换器采用3μm CMOS工艺制作,信噪比为49 dB,积分非线性为±0.5 LSB。     

基于多维时空的NPCA-PSR-IGM(1,1)组合模型的短时交通流预测

针对城市短时交通流序列非线性和混沌性的特点,为提高短时交通流的预测精度,该文提出一种基于多维时空的非线性主成分分析(NPCA)和相空间重构(PSR)的改进灰色(IGM(1,1))组合预测模型。首先,使用数据相关性的非线性主成分分析算法对多维交通流量序列进行时空降维,同时保留影响预测点的主要交通流量数据,从而提高建模的精确度;其次,利用多维时空交通流量序列相空间重构放大交通流量内部的细微特征,以使其内在规律得以充分展现,进一步提升预测精度;最后,结合背景值改进的灰色模型适应于线性、非线性以及所需数据少的特点,进行短时交通流预测。实验结果表明,NPCA-PSR-IGM(1,1)组合预测模型的平均相对误差相比NPCA-PSR-GM(1,1)组合预测模型减小3.12%,其标准偏差相对PCA-PSR-IGM(1,1)组合预测模型从15.7091下降到2.0589。同时与最新的预测模型相比,该组合预测模型也提高了预测精度,达到了较好的预测效果。     

A study on tunable spectral frequency shift method with low phase noise

Based on the theory of dispersion characteristics of double-ring photoelectric oscillator and chirped grating, a broadband ultra-low phase noise spectral frequency shift system is constructed. Firstly, the mathematical model is discussed. Secondly, according to the frequency response of the photonic filter formed by the chirped grating interfering with the optoelectronic oscillation circuit, the simulation of the effect of grating dispersion on oscillation frequency is performed. The simulation results show that the oscillation frequency decreases with the increase of grating dispersion value. In the range of 350—4 000 ps/nm, the oscillation frequency varies from 5 GHz to 16.9 GHz, and the phase noise can reach ?140.5 dBc/Hz at 10 kHz, which realizes the generation of ultra-low phase noise spectral shift with broadband tuning.     

Multi-point path planning based on the algorithm of colony-particle swarm optimization

The problem of multi-point path planning is a NP-hard problem,which is equivalent to finding the shortest path of a starting point and some specific node.Aiming at the problem of multi-point path planning,a retrospective ant colony-particle swarm optimization algorithm was proposed.This algorithm used Floyd-Warshall to transform the graph and combined ant colony algorithm and particle swarm algorithm to find the shortest path.The experimental results show that this algorithm can find the precise solution under small data,at the same time,under a large amount of data,can be better than the maximum minimum ant colony algorithm and genetic algorithm.     

Identity-based cloud storage integrity checking from lattices

With the rapid development of cloud storage,more and more users are storing their data in the cloud.To verify whether the users’ data stored in the cloud is corrupted,one effective method is to adopt cloud storage integrity checking schemes.An identity-based cloud storage integrity checking scheme was proposed on the small integer solution problem over ideal lattices,and it was proven to be secure against the adaptive identity attacks of clouds in the random oracle model.To validate the efficiency of the scheme,extensive experiments were conducted to make performance-comparisons between the scheme and the existing two identity-based cloud storage integrity checking schemes.The experimental results show that the online tag-generation time and the proof-verification time of the scheme are respectively reduced by 88.32%～93.74% and 98.81%～99.73%.     

导航设备中频数字解调的软件实现

本文简明阐明了导航设备中频数字化解调的数据处理过程,介绍了NCO的软件实现,基于该种导航设备的窄带中频特性,对DSP中的牛顿迭代方根运算作了说明。     

塔康机载设备识别信号的设计与实现

音频识别是塔康机载设备的一个重要功能指标。早期的塔康机载设备都是通过硬件输出模拟的识别音来实现的。为了增强识别信号的实用性和使用的方便性,本文提出了一种基于 FPGA 可编程逻辑器件的数字化译码方法,实现了塔康机载设备输出模拟识别音和 ASCII 码形式的识别码。