在线轨面伤损检测软件系统优化设计与实现

针对实际应用中轨面伤损检测系统检测速度较慢的问题,在保证检测精度的前提下,结合轨面图像特点及软件工程的思想,提出了面向算法、编程技术和存储介质3个层面的优化方法。算法优化通过重新设计算法流程,合理取舍步骤,实现算法到CPU的高效映射;编程技术优化使用多线程编程,通过并行运算充分利用处理器的多核优势;存储介质优化通过使用读写快、质量轻、能耗低、体积小的固态硬盘进行图像读写,有效地提升了硬件效率。实验结果表明,优化后平均每幅轨面图像检测耗时由17.94 ms降低到仅8.33 ms,速度提升了53.57%,在分辨率为1 mm的精度下换算成车速约为207 km/h,可以满足铁路轨面伤损在线检测需求。     

一种基于非扫描式F-P标准具的激光告警虚警抑制方法

为了降低激光告警系统的虚警率,提出了一种基于非扫描式F-P标准具结构的光学虚警抑制方法。该方法采用相干长度作为判据,因此可大大抑制背景辐射的干扰。通过计算机仿真验证了该方案的可行性。对该方案中的关键技术F-P标准具的设计进行了详细讨论,定性分析了F-P标准具结构参数对其工作性能的影响,并通过实验优选确定设计参数。结果表明,该方案结构简单,可有效排除非相干光的干扰,光学虚警率近乎为0,漏警率小于0.25%。     

基于物联网的人工智能图像检测系统设计与实现

物联网络的建立促使人工智能领域取得飞跃性进展。传统图像检测方法利用小波能算法进行背景与边缘噪声划分方式进行图像检测,存在低分辨率图像检测精度低、检测速度慢、缺乏图像深度分析等一系列问题。物联网人工智能发展迅速的环境下,提出基于物联网的人工智能图像检测系统设计。采用智能人工像素点特征采集技术(IAPCCT),对图像进行逐点特征提取,运用物联网丰富数据量资源与处理运算能力对采集图像像素点进行特征分析回馈,回馈信号经人工智能信号图像合成模块(AISIS),对信号做图像转换处理并输出分析结果完成图像检测。通过仿真实验测试证明,基于物联网的人工智能图像检测系统设计具有图像检测率高、识别准确度高、运行稳定、处理高效等优点。     

Structural similarity determines search time and detection probability

The recently introduced TSSIM clutter metric is currently the best predictor of human visual search performance for natural images (Chang and Zhang [1]). The TSSIM quantifies the similarity of a target to its background in terms luminance, contrast and structure. It correlates stronger with experimental mean search times and detection probabilities than other clutter metrics (Chang and Zhang [1], [2]). Here we show that it is predominantly the structural similarity component of the TSSIM which determines human visual search performance, whereas the luminance and contrast components of the TSSIM show no relation with human performance. This result agrees with previous reports that human observers mainly rely on structural features to recognize image content. Since the structural similarity component of the TSSIM is equivalent to a matched filter, it appears that matched filtering predicts human visual performance when searching for a known target.     

Detection probability and detection time using clutter metrics

We modified the structure similarity index, which is extensively used for image quality assessment, to be clutter metrics and call them target structure similarity measures (TSSIM). Two methods for calculating the TSSIM metrics were suggested. In this paper, via different mathematical formulas, the metrics are used to predict detection probabilities and detection times. The degrees of correlation between various clutter metrics and both the target detection probabilities and the mean detection times, which are obtained from the Search_2 dataset, are presented. Based on these data, comparisons between TSSIMs and three other typical clutter metrics are demonstrated. Experiment results show the TSSIMrms measure generates much better predictive capabilities for both the experimental detection probabilities and the mean detection times than other clutter measures being compared.     

Vision-based vehicle detection and inter-vehicle distance estimation for driver alarm system

In this paper, we propose a robust real-time vehicle detection and inter-vehicle distance estimation algorithm for vision-based driving assistance system. The proposed vehicle detection method uses the combination of multiple vehicle features, which are the usual Harr-like intensity features of car-rear shadows and additional Haar-like edge features. The combination of two distinctive Haar-like intensity and edge features greatly reduces the false-positive vehicle detection errors in real-time. And, after analyzing two inter-vehicle distance estimation methods: the vehicle position-based and the vehicle width-based, we present a novel improved inter-vehicle distance estimation algorithm that uses the advantage of both methods. Various experimental results show the effectiveness of the proposed method.     

Complex-order Fourier transforms and their implementation

Based on the ABCD matrix formalism, it is shown that by introducing two thin lenses and/or two Gaussian apertures with appropriate geometric parameters into the input and output planes of a general complex ABCD system, the resulting system can be expressed in terms of the complex-order Fourier transform. Detailed analytical results are given and confirmed with illustrative examples.     

基于UML技术的空间基础数据库设计与实现

设计合理的空间基础数据库不仅能提高整个空间数据操作时的性能和效率,而且还可以减少后期的维护修复工作,使整个空间基础数据运行的更加快捷,需要对空间基础数据建立数据库。当前的空间基础数据库设计方法采用ArcSDE数据引擎对空间基础数据进行不断地更新调整,再利用多源空间数据格式转换的技术对空间基础数据库进行设计,存在空间基础数据运行时速度缓慢,计算精度低的问题。为此,提出了一种基于UML技术的空间基础数据库设计方法。该方法首先在空间基础数据库设计中建立空间基础数据索引结构,利用R-树族构建空间基础数据索引树,依据空间基础数据索引树,扫描索引空间基础数据,过滤掉不满足查询条件的空间基础数据对象,使空间数据查询结果可以在额定时间内获得,然后采用空间基础数据点、数据线、以及由数据线组成的区域、一组区域、空间基础数据网络的详细存储方式对空间基础数据进行存储,利用MongoDB驱动程序对矢量空间数据进行存储存储,最后通过对空间基础数据库索引、查询、存储等设计实现了空间基础数据库的建立。仿真实验结果证明,所提方法提高了空间基础数据的建库速度,减少了数据运行的时间,提升了空间基础数据的利用率。     

False Positive and False Negative Effects on Network Attacks

Robustness against attacks serves as evidence for complex network structures and failure mechanisms that lie behind them. Most often, due to detection capability limitation or good disguises, attacks on networks are subject to false positives and false negatives, meaning that functional nodes may be falsely regarded as compromised by the attacker and vice versa. In this work, we initiate a study of false positive/negative effects on network robustness against three fundamental types of attack strategies, namely, random attacks (RA), localized attacks (LA), and targeted attack (TA). By developing a general mathematical framework based upon the percolation model, we investigate analytically and by numerical simulations of attack robustness with false positive/negative rate (FPR/FNR) on three benchmark models including Erd?s-Rényi (ER) networks, random regular (RR) networks, and scale-free (SF) networks. We show that ER networks are equivalently robust against RA and LA only when FPR equals zero or the initial network is intact. We find several interesting crossovers in RR and SF networks when FPR is taken into consideration. By defining the cost of attack, we observe diminishing marginal attack efficiency for RA, LA, and TA. Our finding highlights the potential risk of underestimating or ignoring FPR in understanding attack robustness. The results may provide insights into ways of enhancing robustness of network architecture and improve the level of protection of critical infrastructures.     

Maximum confidence measurements and their optical implementation

Perfect discrimination between non-orthogonal states is forbidden by the laws of quantum mechanics. Several strategies to discriminate optimally between states of an arbitrary set exist, and many of these have been implemented in experiments using optical polarisation. In this paper we discuss maximum confidence measurements and their recent optical implementation.     

USB3.0接口在数据存储系统中的应用

USB3.0的传输速率最快可达5Gbps,因此,为实现大量数据的快速稳定传输,介绍了一种以FPGA为控制核心,DDR2 SDRAM为高速大容量缓存,USB3.0为记录器与计算机进行数据通信接口的高速数据传输系统,通过模块硬件电路及软件协议实现了数据的高可靠性稳定传输,解决了大容量记录器的数据传输速度瓶颈。经长期试验证明：该接口传输速度可稳定到达150M/s,且数据可靠无误,满足任务设计要求。     

纠缠态量子探测系统的恒虚警检测方法研究

纠缠态量子探测是将量子力学与信息科学相结合,应用在目标探测领域的一种新技术,其在灵敏度、抗干扰能力等方面具有突破传统探测技术的潜力.在雷达探测领域,恒虚警检测是一项具有重要的意义和应用价值的技术.然而,对于纠缠态量子探测系统中恒虚警检测方法的研究还没有展开,本文针对这一问题,提出了一种纠缠态量子探测系统的恒虚警检测方法.该方法通过系统对噪声的实时估计,自适应调整检测门限,使得纠缠态量子探测系统在检测过程中始终保持恒定的虚警概率.仿真结果表明,所提恒虚警检测方法是正确和有效的,能够实现纠缠态量子探测系统的恒虚警检测功能.该方法提升了纠缠态量子探测系统的灵活性和适应性,为量子探测技术进一步走向实用及应用奠定了理论基础.     

基于NAS的私有云存储平台的设计与实现

随着大数据时代的到来与高速网络建设的快速推进,数据化网络资源共享已渗透到人们的日常工作、学习、生活当中。数据网络化储存、多人资源共享成为现代信息传播与保存的重要方式。但是,网络储存平台的安全性一直令使用者担忧。因此,各种各样的私有云储存平台孕育而生,为使用者提供相对独立的个人使用空间。经过长期的使用发现,传统的私有云存储平台虽然可以达到一定的安全性,但是,安全性只相对公共开放网盘而言。同时,存在多用户瞬时访问下协议拥堵、大数据交互节点回馈延迟高的问题。针对传统私有云的架构特点与问题产生原因,提出基于NAS的私有云存储平台的设计与实现方法。采用基于NAS的协议加密技术、多路访问优化单元、数据压缩单元对传统私有云存在的问题进行针对性解决。通过仿真实验证明,提出的基于NAS的私有云存储平台的设计与实现方法,具有数据储存安全性高、峰值状态下访问点网络畅通性好、数据网络传输交互率高、延迟小等优点。     

船舶分油机模拟器设计与实现

针对分油机控制系统的仿真设计落后于当前先进控制系统的问题,提出了一种以Alfa Laval S系列分油机的EPC-60控制系统为母型的分油机模拟控制系统。介绍了分油机模拟器的整体结构,设计了以ARM为主控元件的仿真控制箱,实现了网络通信、液晶显示、按键扫描等功能。采用Visual C#编程语言在PC机上设计出仿真控制界面。实验结果表明：基于EPC-60为母型控制系统的分油机模拟器具有功能全、运行稳定、和实物相似度高的优点,能够实现轮机教学实验和海员培训的功能。     

基于PCIe总线的数据采集卡设计与实现

为了实现对多路高速光信号采集,利用FPGA设计基于PCIe总线的数据采集系统。对PCIe总线低速Slave通道与高速DMA通道的关键算法进行了研究。首先,介绍了数据采集卡的硬件构成及基本工作原理,提出了PCIe总线算法需要解决的数据传输问题;然后,分析数据采集卡PCIe总线低速Slave通道和高速DMA通道原理以及实现的关键算法。通过Modelsim和SignalTap工具分别对数据传输算法进行功能验证和在线仿真;最后,将设计数据采集卡互联PCIe上位机进行实际测试。实验结果表明,本设计PCIe总线采用X4接口模式,数据传输系统的数据上传峰值速率为615.38MB/s,可以满足稳定可靠、高带宽、模块化等要求。     

Multifolded torus chaotic attractors: design and implementation

This paper proposes a systematic methodology for creating multifolded torus chaotic attractors from a simple three-dimensional piecewise-linear system. Theoretical analysis shows that the multifolded torus chaotic attractors can be generated via alternative switchings between two basic linear systems. The theoretical design principle and the underlying dynamic mechanism are then further investigated by analyzing the emerging bifurcation and the stable and unstable subspaces of the two basic linear systems. A novel block circuit diagram is also designed for hardware implementation of 3-, 5-, 7-, 9-folded torus chaotic attractors via switching the corresponding switches. This is the first time a 9-folded torus chaotic attractor generated by an analog circuit has been verified experimentally. Furthermore, some recursive formulas of system parameters are rigorously derived, which is useful for improving hardware implementation.     

The effects of air temperature and humidity on the acoustic design of voice alarm systems on underground stations

Sound attenuation of air due to climatic conditions is often assumed to be constant and/or negligible in the electro acoustic design of voice alarm (VA) systems. However, air attenuation variations can be significant in large underground spaces and particularly as the frequency increases to the mid to high frequencies which are the most relevant to speech intelligibility. This investigation evaluates and quantifies the impact of the variability of the most influential climatic parameters, air temperature and relative humidity, on the performance of VA systems in underground stations. Computer simulations were employed to predict the effect of varying these climatic parameters on key performance metrics. Results demonstrated a significant increase in the values of reverberation time parameters with both temperature and humidity, at frequencies critical for speech intelligibility. Consequently the values of speech intelligibility related metrics decreased with rising temperatures and humidity. Hence, the study shows how ignoring temperature and humidity effects can lead to calculation errors in the design of VA systems. These errors could cause over-specification of the absorption required of surface materials, and the inaccurate prediction of acoustic and speech intelligibility related parameters.     

Study on probability of detection for fatigue cracks in sonic infrared imaging

Detection reliability of sonic infrared imaging is one of the increasingly important aspects for out of lab applications. And for the detection reliability evaluation, probability of detection (POD) for different defects under given test conditions has been successfully used as an accepted quantitative measurement. In this study, we test a set of C45 ferritic steel plates with artificial fatigue cracks. Experimental results show that the crack heating response increases with the increasing crack length, and the relationship between the logarithmic form of heat response signal and the crack length appears to be linear. Based on the above statistic characteristics, the linear regression analysis and the Wald method are adopted to estimate the POD function and its confidence interval. The study aims to provide a quantitative evaluation method for detection reliability in sonic infrared imaging.     

基于RapidIO技术的网络交换板卡的设计与实现

为了满足新的信号处理平台使用RapidIO技术来进行重构的要求,实现DSP芯片在信号处理板之间和机箱之间的动态连接配置,提出了一种基于RapidIO的网络交换板卡的设计和实现方式。板卡使用TSI578交换芯片构成RapidIO交换机,来实现信号处理板和网络交换板之间的RapidIO数据包路由交换;使用千兆以太网和光纤来实现机箱间的互连;使用FPGA芯片来实现RapidIO和千兆以太网、光纤数据之间的协议转换。应用结果表明,利用该网络交换板能够很好的实现DSP芯片在板卡间与机箱间的互连重构。     

一种牧场配料系统的设计与实现

提出了一种应用于移动Ad Hoc网络的分布式资源接纳控制机制,在目的节点和中间节点部署不同的资源接纳控制模块,能以接近通话或者分组传输的时间间隔适应网络的动态变化,为业务提供较好的QoS保障,并且能够支持多播及接收者异质性。仿真结果表明,添加资源接纳控制机制后,时延、抖动及丢包率分别降低了25.75%,51.76%和24.15%。