A feedback control method for phase signal demodulation in fber-optic hydrophones

In the realm of acoustic signal detection,the identification of weak signals,particularly in the presence of negative signal-to-noise ratios,poses a significant challenge.This challenge is further heightened when signals are acquired through fiber-optic hydrophones,as these signals often lack physical significance and resist clear systematic modeling.Conventional processing methods,e.g.,low-pass filter(LPF),require a thorough understanding of the effective signal bandwidth for noise reduction,and may introduce undesirable time lags.This paper introduces an innovative feedback control method with dual Kalman filters for the demodulation of phase signals with noises in fiber-optic hydrophones.A mathematical model of the closed-loop system is established to guide the design of the feedback control,aiming to achieve a balance with the input phase signal.The dual Kalman filters are instrumental in mitigating the effects of signal noise,observation noise,and control execution noise,thereby enabling precise estimation for the input phase signals.The effectiveness of this feedback control method is demonstrated through examples,showcasing the restoration of low-noise signals,negative signal-to-noise ratio signals,and multi-frequency signals.This research contributes to the technical advancement of high-performance devices,including fiber-optic hydrophones and phase-locked amplifiers.

A new approach to detecting weak signal in strong noise based on chaos system control

In this paper, a chaos system and proportional differential control are both used to detect the frequency of an unknown signal. In traditional methods the useful signal is obtained through the Duffing equation or other chaotic oscillators. But these methods are too complex because of using a lot of chaos oscillators. In this paper a new method is presented that uses the Rossler equation and proportional differential control to detect a weak signal frequency. Substituting the detected signal frequency into the RSssler equation leads the Rossler phase state to be considerably changed. The chaos state can be controlled through the proportional differential method. Through its phase diagram and spectrum analysis, the unknown frequency is obtained. The simulation results verify that the presented method is feasible and that the detection accuracy is higher than those of other methods.

选择不同对照疫苗对疑似预防接种异常反应信号检测的影响

目的探索不同类型疫苗做对照时的信号检出情况,为疑似预防接种异常反应(AEFI)信号检测中选择适宜对照疫苗提供参考。方法分别选择所有其他疫苗和同技术路线其他疫苗做对照,对所有疫苗和特定疫苗进行信号检测,汇总所有其他疫苗和同技术路线其他疫苗做对照时信号检出数量,相同信号、新出现信号和消失信号个数及其反应分类分布,检测灵敏度和特异度。结果与所有其他疫苗做对照时相比,同技术路线其他疫苗做对照时,各种类疫苗信号检出个数均明显减少,全部信号检出数从501个减少至254个;新出现信号35个,新出现信号比例最大的是多糖疫苗,为24.39%(10/41),反应分类为一般反应(10个)、异常反应(3个)、偶合症(2个);消失信号282个,消失信号比例最大的是重组蛋白疫苗,为94.92%(56/59),消失信号的反应分类为偶合症(53个)、异常反应(23个)、一般反应(13个)。同技术路线其他疫苗做对照时,检测一般反应和异常反应的灵敏度降低,特异度增加,但减毒活疫苗和多糖疫苗中检测一般反应的灵敏度增加。结论不同类型疫苗做对照时,检出信号数差异较大;同技术路线其他疫苗做对照时,可以增加一般反应中信号的检出数量,但可能会造成较多异常反应信号消失。建议对于较严重的异常反应进行检测时,使用所有其他疫苗做对照。

基于活动性检测动态估计噪声的心音降噪算法

针对基于小波分解和最优改进对数幅度谱估计的心音降噪算法存在噪声残留和心音失真的问题,提出一种基于心音活动性检测(HSAD)动态估计噪声的心音降噪算法。通过设计的HSAD判断当前心音帧是否为基础心音帧(FHS),根据判断结果分别采用改进最小值控制递归平均(IMCRA)算法和递归平滑算法对噪声功率进行动态估计与更新,采用非因果先验信噪比,实现心音信号的降噪。实验结果表明,提出算法能更好在提升降噪性能的同时,降低FHS的失真。

铁路通信信号检测控制与编辑系统设计与实现

为提升铁路通信信号检测的效率和智能化水平,设计了通信信号检测控制与编辑系统;应用FreeSql及数据库触发机制、异步TCP通信及多点连接技术、断线重连机制,实现了通信信号检测系统的运行状态监测、任务自动控制、检测数据复核,以及检测日报一键生成功能;试验结果表明,该系统提升了通信信号检测效率和质量,实现了通信信号智能化检测。

同步性质控在海洋地震采集中的重要应用

地震采集中震源和仪器记录的同步性质控对地震资料采集质量至关重要。实际地震采集过程中,由于设备的迭代发展,震源与仪器记录的同步性方面有了较高发展,反而在质控过程中容易忽略。一旦发生非人为设置造成的同步误差,会直接影响到采集资料的质量。而且同步误差通常难以准确测量,造成后期数据处理中无法予以精准消除相应误差。本文主要结合中海油服所使用的设备以及在实际施工过程中出现的问题,探讨触发信号异常和GPS授时系统出现异常造成的同步误差发生原因及相应的解决方案。

Industrial shape detecting system of cold rolling strip

A high-precision shape detecting system of cold rolling strip is developed to meet industrial application,which mainly consists of the shape detecting roller,the collecting ring,the digital signal processing(DSP) shape signal processing board and the shape control model.Based on the shape detecting principle,the shape detecting roller is designed with a new integral structure for improving the precision of shape detecting and avoiding scratching strip surface.Based on the DSP technology,the DSP shape signal processing circuit board is designed and embedded in the shape detecting system for the reliability and stability of shape signal processing.The shape detecting system was successfully used in Angang 1 250 mm HC 6-high reversible cold rolling mill.The precision of shape detecting is 0.2 I and the shape deviation is controlled within 6 I after the close loop shape control is input.

A Model with Traffic Routers, Dynamically Managing Signal Phases to Address Traffic Congestion in Real Time

On-road Vehicular traffic congestion has detrimental effect on three lifelines: Economy, Productivity and Pollution (EPP). With ever increasing population of vehicles on road, traffic congestion is a major challenge to the economy, productivity and pollution, notwithstanding continuous developments in alternative fuels, alternative sources of energy. The research develops accurate and precise model in real time which computes congestion detection, dynamic signaling algorithm to evenly distribute vehicle densities while ensuring avoidance of starvation and deadlock situation. The model incorporates road segment length and breadth, quality and achievable average speed to compute road capacity. Vehicles installed with GPS enabled devices provide their location, which enables computing road occupancy. Road occupancy is evaluated based on number of vehicles as well as area occupied by vehicles. Ratio of road occupancy and road capacity provides congestion index important to compute signal phases. The algorithm ensures every direction is serviced once during a signaling cycle ensuring no starvation. Secondly, the definition of minimum and maximum signal timings ensures against dead lock situation. A simulator is developed to validate the proposition and proves it can ease congestion by more than 50% which is better than any of the contemporary approaches offering 15% improvement. In case of higher congestion index, alternate routes are suggested based on evaluation of traffic density graphs for shortest route or knowledge database. The algorithm to compute shortest route is optimized drastically, reducing computation cost to 3*√2N vis-à-vis computation cost of N2 by classical algorithms. The proposal brings down the cost of implementation per traffic junction from USD 30,000 to USD 2000.

Detecting Objectionable Videos

This paper addresses the problem of detecting objectionable videos, which has never been carefully studied before. Our method can be efficiently used to filter objectionable videos on Internet. One tensor based key-frame selection algorithm, one cube based color model and one objectionable video estimation algorithm are presented. The key frame selection is based on motion analysis using the three-dimensional structure tensor. Then the cube based color model is employed to detect skin color in each key frame. Finally, the video estimation algorithm is applied to estimate objectionable degree in videos. Experimental results on a variety of real-world videos downloaded from Internet show that this method is promising.

Evolution of Road Traffic Congestion Control:A Survey from Perspective of Sensing,Communication,and Computation

Road traffic congestion can inevitably de-grade road infrastructure and decrease travel efficiency in urban traffic networks,which can be relieved by employing appropriate congestion control.Accord-ing to different developmental driving forces,in this paper,the evolution of road traffic congestion control is divided into two stages.The ever-growing num-ber of advanced sensing techniques can be seen as the key driving force of the first stage,called the sens-ing stage,in which congestion control strategies ex-perienced rapid growth owing to the accessibility of traffic data.At the second stage,i.e.,the communica-tion stage,communication and computation capabil-ity can be regarded as the identifying symbols for this stage,where the ability of collecting finer-grained in-sight into transportation and mobility reality improves dramatically with advances in vehicular networks,Big Data,and artificial intelligence.Specifically,as the pre-requisite for congestion control,in this paper,ex-isting congestion detection techniques are first elab-orated and classified.Then,a comprehensive survey of the recent advances for current congestion control strategies with a focus on traffic signal control,vehi-cle route guidance,and their combined techniques is provided.In this regard,the evolution of these strate-gies with continuous development of sensing,com-munication,and computation capability are also intro-duced.Finally,the paper concludes with several re-search challenges and trends to fully promote the in-tegration of advanced techniques for traffic congestion mitigation in transportation systems.

非分光红外(NDIR)探硫传感器的研究与设计

通过调研和分析得出国内非分光红外探硫传感器存在的工艺、检测精度和稳定度问题。文中从气室工艺、光源调制方式与稳定度、设计精密的微弱信号处理电路和恒温控制系统等影响检测结果的因素出发,依次进行改进设计和实验测试,完成气室抛光管的镀金与打磨;并对光源的电调制频率进行反复测试和验证,设计完成一种具有良好平坦特性的微弱信号处理电路。在控温精度为0.1℃的恒温系统中进行实践测试,测试结果表明,所设计的探硫传感器信号的噪声下降约73.7%,检出限达到0.01 ppm,在现有水平的基础上提升近500倍,能够实现低硫的高精密测量,为后续低硫探测的非分光红外传感器研制提供了思路和借鉴。

基于辅助信息补偿和控制信号编码的重放攻击检测方法

向最优控制信号中加入编码信号是实现信息物理系统(Cyber physical system,CPS)重放攻击检测的有效方法,但会造成系统控制性能的损失.如何在保证重放攻击检测率条件下降低系统的控制性能损失是一个值得研究的问题.为此,提出一种基于辅助信息补偿的控制信号编码检测方法,通过向测量值添加辅助信号补偿控制编码信号对最优状态估计的影响.首先,证明了此方案下重放攻击的可检测性,导出检测率的上界与检测函数阈值间的定量关系.其次,证明了加入辅助信号后系统控制信号与未添加编码信息时相同,之前时刻的控制编码信号不会造成累积效应.因此,系统当前时刻的控制性能损失仅与当前时刻编码信号的大小有关.最后,将编码信号的协方差矩阵、检测率和检测阈值之间的关系表示成一个最优化问题,给出了编码信号方差的计算方法.仿真结果表明,本文方法能有效地检测重放攻击的发生,且系统控制性能的损失较小.

基于神经网络的智能交通系统交通信号灯设计

随着城市生活节奏的加快,通过设计智能的交通控制系统提高交通效率是一个重要途径。文章以神经网络在智能交通控制系统中涉及的交通模式分析、交通流量预测、交通控制方式选择等方面的应用为基础,对车流量及车道通行能力、神经网络的模型设计与车流量检测、神经网络模型训练、GUI设计与系统测试进行科学设计与详细分析,以此为实现智能交通灯控制系统的设计提供有益参考,进而实现对信号灯的智能控制,有效缩短车辆在路口的等待时间,缓解交通拥堵。

基于STM32的靶机安控器自动检测系统研究

为保障靶场飞行试验的安全性,安控系统在多个重要靶机项目中得到了成功应用;安控器是安控系统的核心部件,目前其地面检测以人工方式为主,费时费力、效率不高,且检测结果容易受到人为因素影响;文章基于信号门限技术设计了一键式、全自动安控器检测系统方案,硬件以STM32F767ZIT6为主控芯片,通过扩展ADAS3022模数转换芯片、串口转换芯片、信号调理等外围电路,设计了主机板、串口板和电源板,研制了安控器自动检测设备;软件设计了硬件底层驱动、供电控制、接口信息模拟、功能检测与故障告警等模块,实现了安控器的全自动检测;通过对某型安控器检测和认为故障注入测试,结果表明:该系统工作状态稳定,能够实现一键式全自动检测,检测结果可信,可以代替繁琐的人工检测方法,具有一定的工程应用前景。

基于反相积分峰值检测法的高频信号AGC系统

针对现有非射频自动增益控制系统难以处理高频信号的问题,提出了一种反相积分峰值检测方法,并基于此方法设计了高频信号自动增益控制系统。反相积分峰值检测法是针对低频MCU设计的高频信号峰值检测方法,可以实现宽频带上的高精度峰值检测。系统由反相积分峰值检测模块对输出信号进行峰值检测,由MCU控制模块根据峰值检测结果调控可变增益放大模块的增益,实现自动增益控制。实验结果表明:该自动增益控制系统最高工作带宽可达200 MHz,相对误差在0.7%以内,相较现有基于非射频峰值检测法的自动增益控制系统,最高工作带宽在控制精度更高的前提下提升到2倍以上。

基于BP神经网络的光伏发电设备故障检测方法研究

针对光伏发电设备工作过程中存在的故障检测低下问题,设计了集采样、稳压、采样保持和故障采集于一体的集成电路,并提出了故障检测方法。通过分布式测控网络,使系统能够实时、准确地获得光伏发电设备的运行状态。故障检测装置自带计算处理模块智能对比检测数据,为实现故障检测算法提供数据支撑。为了更好地识别光伏发电设备的故障,提出了基于反向传播(BP)神经网络引入可信度检测度量参数的故障监测算法。该算法不仅能够消除误差,并且有很强的抗干扰性。试验结果证明,在不同的干扰信噪比下,检测故障的时间仅在5 ms左右,能够自主地对光伏发电设备运行过程中产生的故障进行识别,极大地提高了光伏发电设备故障检测的工作效率。

基于霍尔负序解调法的无轴承永磁薄片电机径向位移检测方法

传统的无轴承薄片电机系统由于存在位移传感器,难以满足心脏泵等医疗器械高精度、高集成的需求,已有基频位移自检测算法采用传统幅值解调法,对于低极对数电机难以实现两方向位移的解耦,同时需要低通滤波器滤除无效信号,存在延迟长以及误差大的缺陷;高频注入法利用的是电枢磁链之间的互感,并没有利用永磁体磁链,信噪比不高,难以实现稳定悬浮。基于此,该文提出基于霍尔负序解调法的位移检测方法,利用基频永磁磁链与检测霍尔的互感获取位移信息,通过特殊的负序正弦调制霍尔信号并求和的方式,直接解除转角在霍尔信号中的耦合,瞬时解算位移信息,位移解算精度高且无延迟,适用的转速范围宽。该文首先建立磁路模型,通过理论及仿真分析霍尔感应磁链和位移的关系;其次,给出负序解调法的详细数学推导过程并推广至其他极对数电机;最后,在平台上完成已有的两种位移检测算法与所提算法的实验,实验验证所提算法在宽速度范围内的有效性。

基于毫米波雷达的桥梁索杆振动检测及自动控制

在多因素耦合作用下桥梁结构会产生振动,以毫米波雷达技术为测量手段,提出桥梁索杆振动检测及自动控制方法。分析在恒载作用下桥梁索杆静止状态与振动状态的应变能,结合动能、势能和恒载做功等建立索杆平面内与平面外的振动特征描述方程。通过发送多周期连续毫米波雷达探测信号,取得同周期回波信号。根据回波信号与对应瞬时相位得到单频差拍信号及瞬时相位,检测出索杆振动幅值。利用半正定矩阵和正定矩阵等函数,建立令振动幅值达到最小值的桥梁索杆振动自动控制模型。实验结果表明,所提方法检测精准度较高,自动控制效果较好,并有效抑制了振动幅度,具备良好的应用性能。

高速棒材线生产线稳定运行的实践探究

对高速棒材线生产线稳定运行进行研究,通过结合广西钢铁高速棒材生产线实例,探讨3#飞剪、模块轧机润滑、高速区信号检测等实践环节,提出合理运用控制系统、掌握剪切过程和优化升级飞剪设备等,保证3#飞剪高效、顺利运作。并基于优化油膜的油温油流实现稳态控制、科学应用油品在线智能监测系统等,保障模块轧机润滑效果提升。同时针对程序锁定、硬线传输等进行有效处理,避免出现信号闪断等故障,保证高速棒材生产线实现稳定运行。综合研究成果,在3#飞剪控制、模块轧机润滑系统、高速区信号检测等方面的设备适应性改造,有利于促使高速棒材线生产线运行平稳,提高作业效率,减少故障影响因素,旨在进一步提升生产效率,增加企业经济效益。

超塑成形液压机加热平台测温系统的结构及原理分析

针对超塑成形对温度控制有严格要求的状况,对其加热平台进行温度探测,采集加热平台上多点的温度,将温度信号反馈至PLC,通过触摸屏显示,并通过PLC对各点温度进行对比,控制不同加电热管之间或同支电加热管的不同分段处的电流强度,达到平台各点温度迅速平衡的目的。测温系统由热电偶、西门子SM331热电偶模块、西门子S7-300 PLC可编程控制器、西门子FM355 PID闭环控制器、工业触摸屏等组成。通过热电偶直接测量温度输出电动势信号,并把电动势信号转换成PLC内部处理用的数字信号,最终由PLC进行处理后对相应电加热管的开关时间进行控制。