基于GPS的物流车辆智能监控系统设计

为对物流车辆进行精准定位、检测和实时跟踪,需要物流车辆智能监控系统设计。当前使用的监控系统,在物流车辆进行运输的过程中,有遮挡物出现时无法精准的对物流车辆进行定位,当物流车辆停放在室内停车场时可能出现定位不到物流车辆的情况。为此,提出一种基于GPS的物流车辆智能监控系统设计方案。该系统硬件部分包括：GPS车载终端、监控中心服务器群和控制终端三部分,同时将全球定位系统与地理道路信息相结合,利用联通网络与国际互联网传输相关信息;系统软件部分使用联通分组通信技术,通过GIS软件与管理信息系统进行无缝连接,并由单片机S3C2440A向GPS模块发送控制中心下达指令,GPS接收指令并给予反馈,通过有效的分析反馈结果来提高监控终端的运行速度、稳定性以及精准度;GPS定位功能采用TDOA算法对物流车辆进行定位。实验证明,所提系统可以对物流车辆精准定位、实时监测和有效跟踪。     

基于BDS/GPS和百度地图的现代有轨电车监控系统的设计

为实现对现代有轨电车车辆的位置及运行状态进行实时监控,设计了一个基于BDS/GPS和百度地图的现代有轨电车监控系统;定位终端以具有我国自主知识产权的BDS/GPS双模定位模块为主,RFID系统作为辅助定位手段;数据通过HTTP的GET方法提交至服务器,由服务器端的PHP页面自动处理后存储到MySQL数据库,中心管理平台显示页面调用百度地图API,将数据显示在百度地图上;最终该系统可以实时获取并存储列车的位置坐标、速度、时间等信息,并在百度地图上以点、线和图表的形式显示出车辆的坐标和运行轨迹等;测试结果表明,该系统运行稳定,定位精度高,获取数据准确、时延小,能够满足应用需求。     

多参数远程无线监控技术研究

针对我国烟花爆竹的运输现状,基于多参数远程无线监控技术,有针对性地选择压力、温度等多种传感器,运用信号处理技术,将多传感器信号进行处理和融合,利用传感监测技术、GPS卫星定位技术、CDMA数据传输技术等搭建通信系统和监测平台,对烟花爆竹运输车辆状态进行监测和预警及报警。通过进行系统的硬件及软件设计,实现了一种烟花爆竹运输过程的安全监控系统。进一步的,完成了系统的测试试验,试验结果表明,该系统可以实时地采集烟花爆竹运输车辆车厢的安全参数,并具有对数据进行比较,超限预警等功能,系统精度可以达到监控目的,且稳定,可有利地防止爆炸对周边人员和环境的危害。     

商用车维修服务链关键技术研究

作为构建商用车维修服务链的关键设备,设计了一种基于J1939协议的车载商用车故障诊断系统。该系统扩展了传统车载故障诊断系统,利用无线通讯技术将采集到的J1939车辆故障信息和GPS定位信息实时上传至车辆监控中心。目标是实现商用车车辆动态监控、故障诊断和预警以及车辆维修保养服务的网络协同管理。系统以Cortex-A8为主控制器和嵌入式Linux为平台,包括故障采集与分析模块,利用Qt设计用户界面。经多次测试实验,故障诊断快速准确,无线传输数据实时性强,丢包率低。     

基于LabVIEW的支架结构安全监控系统设计

针对路桥施工过程中支架结构的安全性能问题,设计开发一套基于LabVIEW的安全监控系统,通过采集应变和倾角信息,全面地监测支架结构所承受的载荷与稳定性;软件的开发融合了多种技术,利用LabVIEW软件实现串口通信、GPRS网络通信、数据库访问、数据报警以及Web发布等功能,将无线传感器网络采集到的数据信息实时地反映给操作人员,并同时具备数据报警、查询等功能;测试结果显示,系统构建了一个包含10个传感器节点的ZigBee网络,并准确地获得了支架结构在受力变化时参数的变动,且实现了GPRS远程监控的功能,说明系统能够稳定、准确地对支架的应变和倾角信息进行监测,并具有良好的后续开发空间和应用前景。     

基于改进YOLOv3网络的无人车夜间环境感知

环境感知是无人车夜间行驶中的一项关键任务，提出一种改进的YOLOv3网络，以实现夜间对无人车获取的红外图像中行人、车辆的检测，将判断周边车辆的行驶方向问题转化为预测车辆位置的角度大小问题，并与深度估计信息进行融合对周边车辆行驶的距离和速度作出判断，从而实现夜间无人车对周边车辆行驶意图的感知。该网络具有端到端的优点，能实现整张图像作为网络的输入，直接在输出层回归检测目标的边界框位置、所属的类别和车辆的角度预测结果，并和深度估计信息融合得到周边车辆的距离和速度信息。实验结果表明，使用改进的YOLOv3网络对夜间无人车获取的红外图像进行目标检测的时间为0.04 s/帧，角度和速度预测效果较好，准确性和实时性达到了实际应用要求。     

基于GPS的智能农机载高光谱采集系统的初步研究

为了解决精确农业中高密度的和全面的农田信息采集的需要,本系统利用visual basic和map objects对GPS, GIS和RS进行有机集成, 一方面系统通过集成GPS, 能为采集到的光谱数据提供高精度的空间位置属性,实现光谱数据采集、定位和存储一体化; 另一方面通过集成GIS,实现了具有空间属性的光谱数据可视化管理和分析处理, 实时地显示动点轨迹和各图层对应点属性,计算作物微分光谱和植被指数NDVI等功能, 为专家系统和决策支持系统提供充足的信息。     

基于无线数传技术的智能农机载高光谱采集系统的研究

为了解决精确农业中高密度的、全面的农田信息采集、数据无线传输和实时处理分析的需要,文章中所讨论的系统利用计算机技术和无线数传技术对GPS, GIS和RS进行有机集成,一方面系统通过AT89lv52单片机,使差分GPS和高光谱仪有机集成,能为采集到的光谱数据提供高精度的空间位置属性,实现光谱数据采集、定位一体化;另一方面利用nRF905数传模块实现数据采集控制系统与微机的数据信息和控制信息互传;同时利用Visual Basic和Map Objects控件集成GIS,实现了具有空间属性的光谱数据可视化管理和分析处理,实时地显示动点轨迹、各图层对应点属性,计算作物微分光谱和植被指数NDVI等功能,为专家系统和决策支持系统提供充足的信息。     

基于智能视觉的车辆事故预警监控系统设计

针对车辆行驶中驾驶员视觉盲区或注意力不集中而造成的交通事故问题,提出采用智能视觉技术对车辆行驶过程中四周的异常物体进行视频监控,对动态视频场景中的运动目标进行检测、识别与实时测距,通过车辆智能视频监控系统最大程度的为驾驶员提供更多预警信息,预防交通事故的发生。本文介绍了车辆智能视觉监控系统的硬件设计方法与软件工作流程,并研究了运动目标检测算法与单目视觉测距算法,通过仿真实验,验证了本智能视觉车辆监控系统对于运动目标进行检测、识别与智能测距判断的实验结果。     

物联网环境下的车辆监控信息平台设计

为使车辆管理更加科学化以及合理化,并在提高车辆管理水平的同时减少不必要的开支,需要对车辆监控信息平台进行设计。当前采用的车辆监控信息平台设计方法是利用视频图像对其进行监控,监控过程中由于视频储存占用空间大,无法设置缩小占用空间,导致监控不能及时发送信息,存在监控性能较差,安全性低的问题。为此,提出一种物联网环境下的车辆监控信息平台设计方法。该方法首先对车辆监控信息硬件平台进行设计,硬件平台是由通信平台、数据平台以及信息共享平台三部分构成,利用Adaboost算法对车辆监控信息数据进行提取,以提取的车辆监控信息数据为基础,结合REDD方案的分簇性能将终端监控的信息数据传输至通信平台,最后在通信平台进行信息发布与展示,由此完成对车辆监控信息平台设计。实验结果表明,所提方法可对车辆信息进行全方位安全监控,实现车辆的科学化管理,为车辆监控的发展提供有效依据。     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.     

A stereo matching algorithm using multi-peak candidate matches and geometric constraints

Gray cross correlation matching technique is adopted to extract candidate matches with gray cross correla- tion coefficients less than some certain range of maximal correlation coefficient called multi-peak candidate matches. Multi-peak candidates are extracted corresponding to three closest feature points at first. The corresponding multi-peak candidate matches are used to construct the model polygon. Correspondence is determined based on the local geometric relations between the three feature points and the multi-peak candidates. The disparity test and the global consistency checkout are applied to eliminate the remaining ambiguous matches that are not removed by the local geometric relational test. Experimental results show that the proposed algorithm is feasible and accurate.     

Hybrid Wavelength and Code Division Multiple Access in Optical Networks

A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.     

Fiber Modal Index Measurements Based on Fiber Gratings

A novel method based on fiber gratings for measuring the effective indices of fiber modes is proposed. The effective index difference between the core mode and a cladding mode was obtained by analyzing the interference fringe of a pair of cascaded long-period fiber gratings. In order to extract the core mode index from the measured index difference, an index matching oil immersion method is proposed. By analyzing the interaction between the cladding mode and the oil applied on the cladding surface, the mode order and the effective index of the involved cladding mode might be calculated. Experimental results about the interference fringe shifts induced by the oil index and the oil-applied length are also presented.     

Optical Pulse Compression Schemes That Use Nonlinear Bragg Gratings

Nonlinear optical pulse compression of picosecond pulses typically requires long lengths of optical fiber and multiple components. Periodic structures, such as fiber Bragg gratings, are highly dispersive at wavelengths outside of the photonic bandgap. This implies that such gratings can be used as very short all-fiber compressors. In this paper a number of such compression schemes are reviewed involving uniform and nonuniform fiber Bragg gratings, relying on both soliton and nonsoliton compression principles. Experimental results supporting the corresponding underlying theory are also presented. Finally, an extension of one of the compression schemes is shown, which allows the generation of adjustable high-repetition rate soliton trains.