A NEW ADMISSION CONTROL APPROACH BASED ON PREDICTION

Admission control plays an important role in providing QoS to network users.Mo-tivated by the measurement-based admission control algorithm,this letter proposed a new ad-mission control approach for integrated service packet network based on traffic prediction .In the letter ,FARIMA(p,d,q,)models in the admission control algorithm is deployed.A method to simplify the FARIMA model fitting procedure and hence to reduce the time of traffic modeling and prediction is suggested.The feasibility-study experiments show that FARIMA models which have less number of parameters can be used to model and predict actual traffic on quite a large time scale.Simulation results validate the promising approach.     

Advanced approaches to high precision MEMS metrology based on interferometric, confocal, and tactile techniques

Geometrical features of micro-systems can be determined by either tactile or optical profiling techniques, which show different non-linear transfer characteristics. This has to be considered especially, if the instruments operate close to their physical limitations. Depending on the specific measuring task either point-wise or areal optical measurement may be advantageous. Hence, examples for both approaches are discussed. Furthermore, systematic effects, which are related to the measuring principle have to be taken into account, e.g. if sharp edges or slopes are present on the measuring object. As it is shown, for white-light interferometry these difficulties can be solved by a two-wavelength technique.     

一种基于复合测量体制的高精度轨道测量方法

为解决特殊飞行器超长距离飞行时全航路飞行轨迹的高精度测量难题,提出了一种兼容我国目前两种主流测量体制的复合体制高精度测量系统方案和一种复合转发器构建思路,分析论证了其工作原理,建立了基于复合体制的轨道测量精度评估模型,并结合理论轨道完成了系统测量精度评估的仿真计算。结果表明,复合测量体制可以实现飞行器载荷的高效复用和装备资源的有效整合,弥补了单一测量体制轨道覆盖能力的不足,过渡段测速精度提升70%以上。基于其兼容属性,该体制可适用于后续1 000 km以上超长航路飞行器的轨道测量需求。     

A high precision Doppler radar based on optical fiber delay loops

The proposed theory shows that, by using optical fiber delay lines or loops, it is no longer necessary to compress pulses with matched filters for optimum detection and it is possible to suppress interference from undesirable zones. The suppression leads to lessening of Doppler and range ambiguity. The theory further shows that it is feasible to measure Doppler beating with high precision based on a single pulse. Thus, with a single pulse, there is no Doppler and range ambiguity; interference from undesirable range zones due to Doppler range fold-over will no longer present; and the troublesome ground clutter problem would be greatly suppressed. The high precision Doppler beating provides a mechanism to reveal intrinsic characteristics of a target without time average blurring or masking. New information can be acquired on targets of interest for purpose of passive identification.     

基于ADS1278的高精度微应变信号采集系统

以24位工业模数转换器ADS1278为核心,设计了一个高精度微应变信号采集系统,给出对应的前端调理电路和数字采集模块等.模拟测试结果显示,该系统方案可行,可有效采集微应变信号,已成功应用于桥梁振动检测等产品.     

Motion estimation based on global and local uncompensabilityanalysis

This correspondence reports our study of a novel motion estimation technique for image sequence coding by exploiting the uncompensable characteristic of the motion field. Preliminary results indicate that this technique not only reduces the estimation burden drastically but also improves the subjective picture quality and signal-to-noise ratio (SNR).     

基于传感器的精密光学位移测量预测研究

考虑到当前的精密光学位移测量预测因其动态预测能力较差,导致位移测量预测结果误差较大的问题,设计基于传感器的精密光学位移测量预测方法。选择合适的传感器,设定测距获取光学测量原始数据。对采集到的数据进行整理与分析,获取待测目标位移特征参数。使用支持向量机理论结合位移特征参数,构建位移测量预测模型。计算预测模型损失函数,控制预测误差。通过数据采集传感器获取振动系统的位移,将其作为实验对比过程中的对照位移值。经实验结果证实,采用本方法的位移精度高达52%,而位移耗时高达3%,在不同的测距与振幅条件下,此方法的预测误差小于当前方法预测误差,且预测结果与实测结果较为一致。     

基于单片机高精度电子天平设计

本系统是以单片机为核心,设计带有通讯和U盘存储功能的高精度电子天平.数据采集部分采用高精度电阻式应变片压力传感器,数据处理部分采用了24位A/D转换芯片HX711.该天平电路简单,寿命长,应用范围广,可以应用于商场、家庭等场所,成为人们日常生活中不可少的必需品.并且此次电子天平的设计了带有通讯和U盘存储功能,更是向部分实验人员提供了一个很好选择.本次设计采用新型电阻式应变片压力传感器、高精度AD、STC12C5A60S2单片机设计实现,具有测量精度高、低成本,易携带等特点.     

一种基于特征多项式局部逻辑替代新方法研究

将验证和测试阶段的一种特征多项式方法应用于布局后逻辑重综合中,以此寻找满足时序要求的可替换模块,通过在域上计算其特征多项式来比较模块的等价性.可以大大提高综合效率,通过实验结果说明了本方法的有效性,具有一定的借鉴意义.     

A high temperature precision amplifier

A precision operational amplifier has been developed for instrumentation applications in which the circuitry must operate in ambient temperatures as high as 200°C. At 200°C the amplifier maintains an input offset voltage and current of less than 200 μV and 1 nA respectively, a gain bandwidth product of 2.2 MHz, and a slew rate of 5.4 V/μS. The amplifier is fabricated in a standard CMOS process and consumes 5.5 mW of power at a supply voltage of 5 V. A continuous time auto-zeroed amplifier topology is used to achieve the low offset voltage levels. At high temperatures the leakage currents of the sample and hold switches used to achieve auto-zeroing, degrading the offset correction voltages stored on the hold capacitors. This degradation is reduced by using large external hold capacitors and by minimizing the diffusion area of the switches through the use of a doughnut shaped layout. The effect of the voltage degradation is reduced by sensing the offset correction voltage with a low sensitivity differential auxiliary input stage. A new input switch topology is used to reduce the amplifier's input offset current at high temperatures     

基于全局-局部SVM的钢板表面缺陷分类

为了提高钢板表面缺陷分类识别,提出一种新的全局和局部支持向量机分类模型。首先,通过样本提取算法将整个训练样本划分为非边界样本和边界样本。非边界样本用于训练全局支持向量机,并获得两条全局决策边界。边界样本用于寻找测试样本的K-近邻样本,通过训练K-近邻样本获得相应的局部支持向量机。若测试样本位于全局决策边界线两侧,直接给出分类结果,否则,由局部支持向量机进行分类决策。最终,新的模型结合二叉树算法实现了4种钢板表面缺陷的分类问题。实验结果显示,全局和局部支持向量机模型有令人满意的综合性能。     

一种基于全局和局部特征的LBP算法应用

提出一种基于全局和局部特征的LBP人脸识别算法。首先将人脸图像进行LBP提取全局直方图特征,再将图像分块,提取每块的LBP局部直方图特征,最后将全局和局部特征按一定的顺序相结合作为图像的总体特征。然后通过RBF神经网络进行分类识别。在ORL人脸库上的实验结果表明,该算法具有较高的识别率。     

基于TDC-GP2的高精度超声波流量计的设计

基于高精度和可靠性的设计思想,针对传统型超声波流量计精度不高、电路复杂和需要对管道进行改装的问题,提出了一种基于FPGA和TDC-GP2高精度时间测量芯片的流量计系统设计。以FPGA为核心逻辑控制模块,结合时差法超声波流量计的原理,采用TDC-GP2实现时差的精确测量,通过串口上传数据给上位机进行数据处理和结果显示。测试结果表明,系统测量精确度和可靠性满足要求。     

基于时间交替采样技术的高速高精度ADC系统

介绍了一种基于时间交替采样结构的高速ADC系统,整个系统采用全数字方式实现时间交替采样技术,结构灵活多变。使用2片ADC芯片及外围电路、FPGA作为逻辑控制和数据接收缓存,来搭建时间交替ADC系统的硬件电路。其最高采样率可达400MSPS,采样精度为12位。通过分析时间交替ADC系统的原理及其通道误差特性,利用Matlab软件分析通道失配误差来源,对采集到的数据进行误差估计和校正     

高精度DDFS信号源FPGA实现

为进行高精度信号源的设计,同时降低设计成本,以Cyclone Ⅱ系列低端FPGA为核心,利用直接频率合成技术,对正弦信号等数据进行1/4周期压缩存储到ROM中,在外部时钟频率为50 MHz,实现了正弦信号源的设计,同时,实现三角波、锯齿波、矩形脉冲及2-ASK、2-PSK和2-FSK等数字调制信号,系统还具有扫频、指定波形次数等功能.仿真结果表明,信号源精度高,频率调整步进可达0.034 92 Hz,频率范围为0.034 92 Hz~9.375 MHz,制作成本低,功能丰富.     

以CPLD为控制核心的16位高精度数字电压表设计

介绍了基于EDA技术的智能数字电压表的实现。本系统以CPLD为控制核心，在MAX PLUSⅡ环境下采用VHDL语言实现了数据采集、转换及显示。该系统具有集成度高、灵活性强、易于开发、维护、扩展等特点。     

基于SDH网络的高精度授时研究

针对目前基于数字同步体系(SDH)网络的长距离时 频同步精度不高、不易与现有网络相融合等问题,提出了一种采 用桥接测量方式拓展SDH网络无源双向比对授时距离的新方法。分析了桥接测量法的中间站 时延测量误差。搭建了220km的4节点SDH实验网络,通过桥接测量法 跨越两个 SDH网元设备,利用桥接站时延数据的测量结果对终端时钟实施伺服控制,使其跟踪于 主站时钟。授时 系统的同步误差峰-峰值为965ps,均方差为117.7ps。实验结果表明,使用桥接测量和时钟伺服技术不但能有 效拓展授时距离,而且能在SDH网络终端再生与基准时钟高度同步的时间频率信号,达到较 高的授时精度水平。     

一种基于相位测量的快速高精度大范围的激光测距法

为满足快速、高精度和大范围的激 光测距需求,分析了现有单频和多频相位激光测距方法存在的 问题,提出了基于降频及高精度测时技术的 相位激光测距方法,并根据测距 要求以及按照测尺频率、测时精度和参考频率的顺序建立了测距系统参数选择模型,进而 按照测距参数需求搭建了实 验系统。实验表明,在300kHz单频测尺、260kHz参考频率和50ps测时精度条件下,实验系统具有500m测距范围、1.08mm 测距精度和0.03～0.04s测量速度,可为快速、高精度和大范围测距 奠定基础。