Scaling Argument of Anisotropic Random Walk

In this paper, we analytically discuss the scaling properties of the average square end-to-end distance 〈R²〉for anisotropic random walk in D-dimensional space (D≥2), and the returning probability P_n( r₀) for the walker into a certain neighborhood of the origin. We will not only give the calculating formula for 〈R²〉and P_n(r₀), but also point out that if there is a symmetric axis for the distribution of the probability density of a single step displacement, we always obtain 〈R²_⊥n〉～n, where ⊥ refers to the projections of the displacement perpendicular to each symmetric axes of the walk; in D-dimensional space with D symmetric axes perpendicular to each other, we always have 〈R_n²〉～n and the random walk will be like a purely random motion; if the number of inter-perpendicular symmetric axis is smaller than the dimensions of the space, we must have 〈R_n²〉～n² for very large n and the walk will be like a ballistic motion. It is worth while to point out that unlike the isotropic random walk in one and two dimensions, which is certain to return into the neighborhood of the origin, generally there is only a nonzero probability for the anisotropic random walker in two dimensions to return to the neighborhood.     

基于空间转换网络的端到端车牌检测与识别

在复杂场景中,许多现有的车牌检测和识别方面 的研究方法存在数据集单一且有限、算法复杂等问题。因此提出了一个端到端的统一网络: 残差-空间变换-连接时序分类融合的 车辆号牌检测识别网络(LPDR-RSCNet)。该网络结合残差神经网络、空间变压器网络和连 接主义者时间分类,联合训练检测和识别模块,以减少中间错误积累。通过在残差神经网络 提取特征过程中引入空间变换网络,使特征提取器具有平移不变性、旋转不变性和缩放不变 性;在分类器引入连接时序分类,可以自动识别图片标签和特征之间的关系。同时,还可以 适应可变长度序列的识别。在中国城市停车场数据集(CCPD)上进行了比较实验,CCPD是一 个大规模、多样的中文车牌数据集。实验证明LPDR-RSCNet模型在实际应用中可实现98.8％ 的识别精度和34 fps的速度,并且相较于YOLO9000、Faster-RCNN、SSD300, 具有更好的检测准确度,可满足智能交通系统中对移动车辆实时车牌检测和识别的要求。     

Research on End-to-End Encryption of TETRA

1Introduction TETRAisanETSI standardizeddigitalradiooperat ingsystembasedontrunkedmobileradiotechnolo gy[1-3].ItistypicallydesignedfortheProfessionalMo bileRadio(PMR)marketandincludessystems,typi callyforMilitaryandPublicSafetyorganizations,as wellasPubli…     

Worst case response times in a Bluetooth piconet: scheduling combining 1-RR or E-RR with FIFO or EDF

In this paper, we focus on the Bluetooth wireless network, analyzing its ability to support the Quality of Service (QoS) requirements defined by QoS sensitive applications. The QoS perceived by the application depends on the scheduling mechanisms chosen at the medium access layer. Hence, we propose to evaluate the ability of different Bluetooth scheduling algorithms (1-RR/FIFO, 1-RR/EDF, E-RR/FIFO and E-RR/EDF) to guarantee bounded transmission delays. First, we establish a bound on the worst case response time of any sporadic message using a worst case analysis. We then compare the computed bounds with the worst case response times obtained by simulation for different traffic distributions and show in which configurations our bounds are tight. We finally compare those different schedulings and show how to extend our results on worst case response times taking into account message segmentation.     

Improving the Analysis of Distributed Non-Preemptive FP/DP* Scheduling with the Trajectory Approach

In this paper, we are interested in real-time flows requiring quantitative and deterministic Quality of Service (QoS) guarantees. We focus more particularly on two QoS parameters: the worst case end-to-end response time and jitter. We consider a non-preemptive scheduling of flows, called fp/dp*, combining fixed priority and dynamic priority established on the first node visited in the network. Examples of such a scheduling are fp/fifo* and fp/edf*. With any flow is associated a fixed priority denoting the importance of the flow from the user point of view. The arbritation between packets having the same fixed priority is done according to their dynamic priority. A classical approach used to compute the worst case end-to-end response time is the holistic one. We show that this approach leads to pessimistic upper bounds and propose the trajectory approach to improve the accuracy of the results. Indeed, the trajectory approach considers the worst case scenarios experienced by a flow along its trajectory. It then eliminates scenarios that cannot occur.     

IPv6部署对移动网络QoS影响分析

随着物联网的兴起和移动数据业务的增长,在移动网络中引入IPv6成为大势所趋。首先介绍了移动网络中Qos的架构,其次从终端、无线接入侧、核心网和外部承载网等方面对移动网络引入IPv6后给QoS所带来的影响进行了分析,提出了移动网络在向IPv6演进的过程中保障QoS需要注意的问题及方案,为在移动网络中引入IPv6提供了参考。     

话务网管端到端数据质量监控的设计与实现

为了解决话务网管中性能统计的完整率问题,通过对系统中数据流向进行研究,逐层分析控制点,关联性能统计与相关配置信息,从数据源到上层应用分层检测,做到分层监控,将数据完整性检测结果以矩阵图形式展现,达到数据完整性可视化.采用监控矩阵图直观地定位问题点的方法,有助于快速分析、解决问题,缩短了对网络运行分析和监控的影响时间,从而有力支撑网络精细化生产的需要.     

CDMA 2000 1xEVDO Rev.A系统的QoS应用

随着数据用户和数据业务的迅猛发展,运营商网络的承载压力不断加大,如何综合考虑网络资源利用最大化和用户间公平性,是目前网络运行商面临的主要问题。文章对QoS概念、QoS模型、3G业务的QoS分类以及CDMA 2000 1xEVDORev.A端到端QoS的体系结构进行了说明,并对EVDORev.A系统中端到端QoS保证的系统实现进行了介绍。文章认为第三代无线通信技术CDMA 2000 1xEVDORev.A能提供端到端的QoS解决方案,它不仅增强了对实时业务的支持,还可以大大提升网络服务性能。     

复杂对抗下军事通信系统的随机延迟分析

随着信息化技术的发展,现代军事指挥越来越依靠综合化、集群化的军事通信系统。在战争局势复杂多变,尤其是敌方干扰严重、战场环境复杂等对抗性强的环境下,如何确保有效军事情报及时地准确地传递给指挥者显得尤为重要。针对战场有效数据产生的随机性和传输过程的不稳定性,提出了一种基于随机网络演算的端到端延迟分析方法。由此获得的端到端延迟上界,不仅为有效信息的传输提供了实时性能保证,而且能充分的利用系统资源。这对于军事通信系统的设计以及传输系统的性能改善有着非常重要的指导意义。     

WSN中基于势能场的多策略路由协议

文章结合无线传感器网络（WSN）中流量分布的向心性特点,借鉴物理学中势能场的概念与机理,提出一种开放的路由协议实现框架。利用不同的网络参数构造不同的“虚拟势能场”,叠加后形成的复合势能场将驱动数据分组沿着势场梯度变化最快的方向移动,一方面可以最终将网络中的数据分组汇聚于目的节点,实现路由协议的基本功能;同时,在动态时变“虚拟势能场”的调节下,还可以为路由协议附加各种有利于实现其他优化目标的策略与属性,如能耗均衡、拥塞避免、支持服务质量保障和利于数据聚合等,在无线传感器网络中实现多策略路由。作为例子,文章提出了一个基于势能场的提供实时传输的路由协议,它能在严格保障实时分组获得最小化端到端延迟的前提下,有效缓解网络拥塞,提高全网吞吐量。