Tracking Mobile Users with Uncertain Parameters

A method of reducing the wireless cost of tracking mobile users with uncertain parameters is developed in this paper. Such uncertainty arises naturally in wireless networks, since an efficient user tracking is based on a prediction of its future call and mobility parameters. The conventional approach based on dynamic tracking is not reliable in the sense that inaccurate prediction of the user mobility parameters may significantly reduce the tracking efficiency. Unfortunately, such uncertainty is unavoidable for mobile users, especially for a bursty mobility pattern. The two main contributions of this study are a novel method for topology-independent distance tracking, and a combination of a distance-based tracking with a distance-sensitive timer that guarantees both efficiency and robustness. The expected wireless cost of tracking under the proposed method is significantly reduced, in comparison to the existing methods currently used in cellular networks. Furthermore, as opposed to other tracking methods, the worst case tracking cost is bounded from above and governed by the system, such that it outperforms the existing methods. The proposed strategy can be easily implemented, and it does not require a significant computational power from the user.     

基于无线传感器网络的活动目标跟踪

无线传感器网络WSN是目前通信和计算机领域的研究热点。WSN的各种应用中,活动目标跟踪在军事和民用上都具有广泛的应用前景,也是技术上具有挑战性的课题。总结了目前传感器网络目标跟踪中节点的组织和路由,目标的侦测、定位,目标轨迹的估计和预测等方面的一些研究成果,比较了各个方法的优缺点,提出了以后跟踪应用中值得注意的问题和方向。     

面向移动目标跟踪的动态联盟平滑切换方法

针对传统动态联盟离散生成方式所导致的能耗较大且历史信息易失等不足,提出一种动态联盟的平滑切换方法。首先,预估目标移动的下一位置;然后,检测联盟切换的触发条件;最后,通过新盟主选择、新旧盟主交接以及盟员变动等一系列过程实现联盟的平滑切换。并在目标丢失后,进行联盟修复。联盟的平滑切换将避免联盟因目标移动而反复生成和解散,并保持和利用联盟收集的历史信息。仿真结果显示,该方法能有效维持动态联盟,实现联盟的平滑切换,与传统动态联盟方法相比,降低了系统的能耗和通信成本,提高了目标跟踪的精度,验证了该方法的有效性。     

移动卫星通信终端天线极化跟踪研究

针对移动通信终端天线的极化失配损失问题,利用两个正交线极化天线结合相应的馈电网络实现了任意方向的线极化波,用于移动状态下的天线极化跟踪。提出了通过控制两个正交线极化天线的相位差来接收任意线极化波的方法,并给出了相位差与极化角的关系。当两个正交线极化天线增益及其对应通道间的幅度和相位均相同时,接收到的信号强度随相位差的变化而作余弦,且当相位差ψ为2θ-π2时,信号强度有最大值。基于该方法进行理论仿真,并得到了极化跟踪曲线,与测试结果相比,吻合良好。将该方法应用到卫星通信移动终端,在运动过程中信号稳定,未出现明显极化失配现象,验证了该算法的有效性。     

认知无线电中基于高斯混合概率假设密度滤波的主用户跟踪算法

基于随机集的高斯混合概率假设密度滤波算法是一种典型的多目标跟踪算法,可以在目标数目未知的情况下进行多目标跟踪,但是该算法要求已知目标的起始位置,在很多情况下,目标的起始位置信息是无法获得的。本文针对这一问题,提出了改进的高斯混合概率假设密度滤波算法,并将本文算法应用于认知无线电系统的主用户跟踪问题。该算法利用双向预测的方式对检测结果进行估计,即使用正向预测算法来估计现存主用户的位置,然后采用后向预测算法来搜索新生的主用户并估计出新生主用户的位置。本文算法的主要优点是在主用户的数目、出现的时间和起始位置均未知的情况下仍可以有效的跟踪目标。最后,通过仿真对本文算法的性能进行了分析。仿真结果表明,本文算法在误检率较高的情况下可以准确地跟踪主用户。      

车式移动机器人轨迹跟踪控制方法

针对车式移动机器人轨迹跟踪这一典型控制任务,本文提出一种滑模轨迹跟踪控制方法.该方法采用PI型滑模面设计等效控制律,利用变速函数代替符号函数获得切换控制率,并运用Lyapunov理论证明系统的稳定性.仿真结果表明该方法不但能使机器人有效跟踪任意参考轨迹,而且能减小在控制中的抖振现象,即使在外界干扰影响的情况下,也具有良好的控制品质.     

移动机器人全局轨迹跟踪的自适应滑模控制

讨论了两驱动后轮角速度为控制输入的移动机器人轨迹跟踪问题，针对含有未知参数的非完整移动机器人运动学模型．基于反演（backstepping）控制算法的思想设计了变结构控制的切换函数，并由此构造了具有全局渐近稳定的白适应滑模轨迹跟踪控制器。该方法设计过程简单并具有直观的稳定性分析，适用于移动机器人的全局轨迹跟踪控制。仿真结果表明了该方法的有效性和正确性。     

基于OPNET的移动IP通信仿真跟踪及分析

基于OPNET仿真平台,本文设计了一个简单的移动IP网络,并对其通信过程进行了仿真跟踪,掌握了数据包的流动路线、数据包在传送过程中封装和拆封、移动IP网络在不同阶段通过不同网段进行通信的情况,并对发送和接收的数据进行了分析,对网络的总体性能进行了评估,从而为设计和优化IP移动网络提供参考。     

Authentication of Mobile Users in Third Generation Mobile Systems

The goal of the third-generation mobile systems is to provide worldwide operation, enhance service capabilities, and improve performance over the second-generation mobile systems. In this paper, we propose an authentication procedure for third-generation mobile systems. The authentication procedure is a protocol suite consisting of two subprotocols: a certificate-based authentication (CBA) protocol and a ticket-based authentication (TBA) protocol. Only two parties, MS and VLR, are involved in executing our protocol. Our authentication procedure uses both public- and secret-key cryptosystems. Our authentication procedure not only provides uniform authentication across domains, but also reduces computational costs in the process of repeated authentication. We provide firm proof of our procedure's correctness.     

Hyper-Erlang Distribution Model and its Application in Wireless Mobile Networks

This paper presents the study of the hyper-Erlang distribution model and its applications in wireless networks and mobile computing systems. We demonstrate that the hyper-Erlang model provides a very general model for users' mobility and may provide a viable approximation to fat-tailed distribution which leads to the self-similar traffic. The significant difference from the traditional approach in the self-similarity study is that we want to provide an approximation model which preserves the Markovian property of the resulting queueing systems. We also illustrate that the hyper-Erlang distribution is a natural model for the characterization of the systems with mixed types of traffics. As an application, we apply the hyper-Erlang distribution to model the cell residence time (for users' mobility) and demonstrate the effect on channel holding time. This research may open a new avenue for traffic modeling and performance evaluation for future wireless networks and mobile computing systems, over which multiple types of services (voice, data or multimedia) will be supported.     

基于评分机制的移动用户隐私保护方案研究

开发人员的技术缺陷和用户隐私数据的潜在商业价值,使得用户隐私面临巨大安全威胁,针对恶意应用软件和应用自身缺陷带来的安全危机,结合应用市场的评分评价机制,提出一种方便用户安装和使用移动应用的用户隐私保护方案MURT。此方案提供接口设定终端应用信任阈值,并在应用和隐私数据之间添加强制访问控制模块,该模块会拦截综合评级低于信任阈值的应用的访问请求,并为请求者提供虚假服务,保证应用顺利运行的前提下确保隐私数据的完整性和安全性。方案在Android平台上编码实现,实验表明:MURT在保障用户体验的基础上,有效地扼制了隐私数据泄漏。     

中国3G智能手机消费者需求的区域性差异研究

通过对我国14个城市2 648名消费者的实证调查,从消费者心理层面出发,基于生活方式和价值观的差异性,并结合地理行政划分与经济发展水平,将我国消费者划归到三大区域。研究表明,3个区域的消费者在"身份/尊贵"、"基本/实用"、"时尚/个性/娱乐"和"价格关注"4个3G手机购买和需求动机因子上存在显著的区域性差异,最后对上述需求差异进行了归纳。     

Intelligent Handoff for Mobile Wireless Internet

This paper presents an intelligent mobility management scheme for Mobile Wireless InterNet – MWIN. MWIN is a wireless service networks wherein its core network consisting of Internet routers and its access network can be built from any Internet-capable radio network. Two major standards are currently available for MWIN, i.e., the mobile IP and wireless LAN. Mobile IP solves address mobility problem with the Internet protocol while wireless LAN provides a wireless Internet access in the local area. However, both schemes solve problems independently at different layers, thereby some additional problems occur, e.g., delayed handoff, packet loss, and inefficient routing. This paper identifies these new problems and performs analyses and some real measurements on the handoff within MWIN. Then, a new handoff architecture that extends the features of both mobile IP and wireless LAN handoff mechanism was proposed. This new architecture consists of mobile IP extensions and a modified wireless LAN handoff algorithm. The effect of this enhancement provides a linkage between different layers for preventing packet loss and reducing handoff latency. Finally, some optimization issues regarding network planning and routing are addressed.     

移动互联网用户隐私信息检测保护技术研究及应用

智能终端及应用作为“大连接”中的重要节点和业务载体，直接或间接接触大量用户敏感隐私信息，近年来，App强制授权、过度索权、超范围收集个人信息的现象大量存在， 违法违规使用个人信息的问题十分突出，用户隐私泄露的情况愈演愈烈，安全及隐私问题引发社会广泛关注。本论文根据不同源头的APP隐私安全风险全面梳理排查，创新提出“静态权限检测+动态行为特征+网络DPI智能分析”的隐私信息检测防护技术体系，实现了敏感权限智能分析、违规索权动态监控、隐私泄露探测预警、敏感信息深度追踪，确保移动应用APP安全、可信、可控，保障了业务单位和用户隐私安全权益。     

Adaptive Trajectory Tracking Control of Wheeled Mobile Robots with Nonholonomic Constraint

Wheeled mobile robots (WMR) have been widely applied in a lot of areas that range from the teleoperated Sojourner on the Mars Path finder mission to cleaning robots in the Paris Metro. As a result, the interest of the Robotics Community for the wheeled mobile robots’ tracking control problem has grown rapidly[1-13]. WMR is one of the well-known system with nonholonomic constrains and it contains a class of mechanical systems characterized by kinematic constrains that are not integrable an…     

参数不确定移动机器人全局轨迹跟踪的自适应滑模控制

通过对一类质心和几何中心不重合情况下移动机器人轨迹跟踪问题的研究,得到了两独立驱动轮角速度为控制输入的机器人运动学模型.对于车轮半径和两驱动轮之间距离参数已知的情况,基于反演控制的思想设计了变结构控制的切换函数,构造了具有全局渐近稳定的滑模轨迹跟踪控制律,并针对这两个参数未知时,通过自适应方法对其进行参数估计,给出了自适应滑模轨迹跟踪控制律的设计方法.该方法设计过程简单且具有直观的稳定性分析,适用于移动机器人的全局轨迹跟踪控制.仿真算例验证了所提控制律的有效性和正确性.     

一个可切实服务于运营商的移动无线因特网

本文在简单介绍了移动IP及其路由优化，无线局域网（WLAN）和GPRS的基础上，提出了一个新的利用移动IP来融合WLAN和GPRS的移动无线因特网的网络结构，详细论述了其多连接的路由过程，平滑垂直切换，AAA，并做了简要的性能分析。     

基于无线传感器网络的移动机器人定位导航系统

设计了一种基于无线传感器网络(WSN)的移动机器人轨迹跟踪定位系统,通过测算移动机器人和信标节点之间的无线电接收信号强度(RSSI)进而估计出它们之间的距离,采用自适应的扩展卡尔曼滤波算法对RSSI数据处理得到机器人的当前位置、速度、加速度等状态信息.为了提高系统的实时性和计算效率,动态选用网络中一部份信标节点进行轨迹跟踪定位计算,降低了移动机器人CPU的负担.采用CC2430芯片作为节点的通信和数据处理单元,现场试验结果表明该方法具有轨迹跟踪定位精度高、实现简单、成本低廉等特点.     

A Novel Modelling Technique for Tracing Mobile Users in a Cellular Mobile Communication System

Mobility of users in a cellular mobile communication system has been formulated mathematically under generalized conditions. Based on this model a computer simulation has been developed. This mobility model is used to examine cell residence time distribution in cellular environments defined by different cell sizes and mobility parameters. It is shown that cell residence time can be described by the generalized gamma distribution.     

移动机器人轨迹跟踪的模糊PID-P型迭代学习控制

本文针对移动机器人轨迹跟踪控制问题的研究,提出了一种基于移动机器人运动模型的模糊开闭环PID-P型非线性离散迭代学习控制方法,给出了PID-P型迭代学习的收敛条件及其证明过程,并采用模糊控制的原理整定PID三个学习增益矩阵的参数.该控制方法提高了移动机器人对特定轨迹的重复跟踪能力,具有算法实现简单的特点.实验仿真结果表明,采用模糊开闭环PID-P型迭代学习控制算法对轨迹跟踪是可行有效的.