An range-free localization scheme for large scale underwater wireless sensor networks

In this paper, we study an area localization problem in large scale underwater wireless sensor networks (UWSNs). The limited bandwidth, the severely impaired channel and the cost of underwater equipment all make the underwater localization problem very challenging. Exact localization is very difficult for UWSNs in deep underwater environment. We propose a range free method based on mobile detachable elevator transceiver (DET) and 3D multi-power area localization scheme (3D-MALS) to address the challenging problem. In the proposed scheme, the ideas of 2D multi-power area localization scheme (2D-ALS) and utilizing DET are used to achieve the simplicity, location accuracy, scalability and low cost performances. The DET can rise and get down to broadcast its position. And it is assumed that all the underwater nodes underwater have pressure sensors and know their z coordinates. We evaluate the performances of 2D-ALS and our proposed 3D-MALS schemes under both ideal and non-ideal channel propagation conditions, in terms of localization error and localization ratio. The simulation results show that our proposed scheme is much more efficient than the 2D-ALS.     

基于抗局部攻击的无线传感器网络定位方法

为了解决无线传感器网络定位过程中的常见安全问题,提出了一种抗攻击的定位方法.该方法通过高效的认证机制和检测机制帮助待定位节点验证信标节点的合法性及检测定位信息的可靠性,筛选出值得信赖的定位信息用于节点的定位计算,能够有效抵御定位过程中的女巫攻击和虫洞攻击.实验结果验证了该方法能够在存在安全威胁的网络环境下,有效提高无线传感器节点的定位精度.     

New Iris Localization Method Based on Chaos Genetic Algorithm

This paper present a new method based on Chaos Genetic Algorithm (CGA) to localize the human iris in a given image. First, the iris image is preprocessed to estimate the range of the iris localization, and then CGA is used to extract the boundary of the iris. Simulation results show that the proposed algorithms is efficient and robust, and can achieve sub pixel precision. Because Genetic Algorithms (GAs) can search in a large space, the algorithm does not need accurate estimation of iris center for subsequent localization, and hence can lower the requirement for original iris image processing. On this point, the present localization algirithm is superior to Daugman‘s algorithm.     

一种基于直方图的车辆检测方法

获得车辆图像的准确定位是视频交通检测的关键,在分析传统车辆检测方法不足的基础上,提出的基于直方图的检测方法,能够提高图像分割的准确性,确保对车辆目标的顺利提取,具有一定的实际应用价值。     

基于GPS与图像融合的智能车辆高精度定位算法

车辆自定位是实现智能车辆环境感知的核心问题之一.全球定位系统(Global Positioning System,GPS)定位误差通常在10 m左右,不能满足智能车辆的定位需求;惯性导航系统成本较高,不适于智能车辆的推广.本文在视觉地图基础上,提出一种基于GPS与图像融合的智能车辆定位算法.该算法以计算当前位置距离视觉地图中最近一个数据采集点的位姿为目标,首先运用GPS信息进行初定位,在视觉地图中选取若干采集点作为初步候选,其次运用Oriented FAST and Rotated BRIEF(ORB)全局特征进行特征匹配,得到一个候选定位结果,最后通过待检测图像中的局部特征点与候选定位结果中的三维局部特征点建立透视n点模型(Perspective-n-Point,Pn P),得到车辆当前的位姿,并以此对候选定位结果进行修正,得到最终定位结果.实验在长为5 km的路段中进行,并在不同天气及不同智能车辆平台测试.经验证,平均定位精度为11.6 cm,最大定位误差为37 cm,同时对不同天气具有较强鲁棒性.该算法满足了智能车定位需求,且大幅降低了高精度定位成本.     

一种基于地图辅助的自动驾驶视-惯融合定位方法

视觉同步定位与建图(Simultaneous Localization and Mapping, SLAM)方法广泛应用于自动驾驶领域。传统的方法利用车载摄像头表征车辆周围环境，同时估计自身位置，当车辆运动过快时，定位精度和鲁棒性会下降。针对此问题，本文提出一种地图辅助的视-惯融合定位方法。该方法在ORB-SLAM2(Oriented FAST and Rotated BRIEF SLAM2)的基础上拓展地图保存功能，将建图和定位拆分为两个独立模块，车辆首先以较慢的速度构建并保存具有视觉特征的地图，然后，在第2次运行时车载计算机调用预先保存的地图实现精确且稳定的定位性能。由于构建地图阶段采用了图优化算法融合惯性测量单元(Inertial Measurement Unit, IMU)的信息，地图误差得到有效校正。在KITTI数据集场景和实际场景中验证了所提方法的良好性能。实验结果表明，所提方法在4, 8, 16 m·s-1 驾驶速度下的定位精度分别为2.59，2.61，2.73 m，图像失帧率和路径丢失率分别为3.76%和1.38%，3.89%和1.69%，4.27%和1.84%。相比原始的ORB-SLAM2方法，系统定位精度和鲁棒性均得到了提高。     

Rigid sensor allocation and placement technique for reducing the number of sensors in thermal monitoring

Using embedded thermal sensors, dynamic thermal management (DTM) techniques measure runtime thermal behavior of high-performance microprocessors so as to prevent thermal runaway situations. The number of placed sensors should be minimized, while guaranteeing accurate tracking of hot spots and full thermal characterization. In this paper, we propose a rigid sensor allocation and placement technique for determining the minimal number of thermal sensors and the optimal locations while satisfying an expected accuracy of hot spot temperature error based on dual clustering. We analyze the false alarm rates of hot spots using the proposed methods in noise-free, with noise and sensor calibration scenarios, respectively. Experimental results confirm that our proposed methods are capable of accurately characterizing the temperatures of microprocessors.     

基于小波和RBF神经网络的多传感器时间对准算法研究

提出利用小波降噪和RBF神经网络进行时间对准算法,该方法先对采集到的数据进行降噪处理,为下一步操作提供准确数据;然后利用RBF神经网络将不同传感器采集不同采样周期的数据对应到同一个时间点上,进行多传感器时间对准,为后面数据特征提取和数据融合提供高精度数据支持。通过仿真结果与其它方法的对比可得该方法运算速度快,具有数据修正能力和精确度高的特点,适用于多传感器的时间对准。     

基于残差卷积网络的浮置板轨道钢弹簧损伤检测

针对传统故障诊断方法难以有效检测浮置板轨道钢弹簧损伤这一挑战性问题，提出了一种基于一维残差卷积网络的损伤检测方法；建立了车辆-浮置板轨道耦合动力学模型，得到了多种工况下列车通过导致的浮置板振动响应数据集；利用残差卷积网络对不同损伤情形下的振动响应进行特征提取和数据分类，实现了对损伤钢弹簧的准确定位；研究了残差卷积网络在不同传感器布置方案上的检测性能，分析了损伤钢弹簧和传感器之间的复杂位置关系对检测性能的影响规律，优化并确定了经济可靠的传感器布置方案。研究结果表明:传感器的位置越靠近浮置板中部，残差卷积网络对不同损伤情形下的数据分类准确性和鲁棒性越好；传感器的布置数量增多，损伤检测方法的性能也随之改善，但传感器过多地集中于浮置板中部并不会带来显著的性能提升；在浮置板中部的钢弹簧损伤比在浮置板端部的钢弹簧损伤更难识别；损伤检测方法在全覆盖式布置方案下达到了99.11%的分类准确率，对复杂多变的检测情景具有良好适应性，而优化后双传感器布置方案和三传感器布置方案的分类准确率分别达到了98.23%和98.96%，优化后传感器布置方案具有良好的检测性能，同时也保持了损伤检测方法对复杂情景的适应性。      

不均匀地质条件下地震动目标定位方法

针对不均匀地质条件下地震动信号传播速度差异造成定位精度较低的问题,通过将位置域的传播速度转换为时延域的等效传播速度,提出了一种基于时延-等效传播速度检索表的到达时间差(TDOA)目标定位方法.对等腰直角三角形传感器阵列的定位盲区进行了仿真分析,为消除定位盲区,提出了五元十字阵传感器布置方法;进行了场地试验,对运动车辆进行目标定位,对基于时延-等效传播速度检索表的TDOA定位方法与固定传播速度TDOA定位方法的定位结果进行了比较,结果表明,前者的定位效果远优于后者.      

基于几何约束及迭代的NLOS环境定位算法

针对在非视距 （non-line-of-sight,NLOS）环境中传统最优化定位算法抗NLOS误差能力较弱、且需要一个较准确的初始估计位置以确保算法收敛这一问题,提出一种应用在双基站场景下的基于几何约束及迭代的定位算法. 通过引入最大散射半径作为几何约束条件,以线性迭代方式进行一维全局搜索,并采用最小二乘算法获得移动台（mobile station,MS）初始估计位置,然后利用设定的阈值门限对各初始位置点进行筛选,最后通过加权平均获得MS的最终估计位置. 仿真结果表明:当散射半径为200 m时,本文算法的定位误差在200 m以下的概率能达到100%;在相同环境下,本文算法计算时间开销仅是网格搜索法的0.4%.      

基于DAB信号的城市车辆定位方法研究

通过阐述数字音频广播的特点,发现DAB／GIS组合定位是一个高精度、高可靠性、经济、适用于车辆在复杂城市环境中的定位方案。同时,基于DAB定位伪距测量的原理和定位实现方法,可有效分析DAB信号定位技术的特点。该方法可对现有定位技术如GPS定位形成有益的补充。     

A real-time collision-free path planning of a rust removal robot using an improved neural network

In this paper, a real-time collision-free path planning of the rust removal robot in a ship environment is proposed, which is based on an improved biologically inspired neural network algorithm. This improved algorithm is based on the biologically inspired neural network and modified with obstacle detection sensors and kinematic state templates, and is implemented in a ship rust removal robot planning system for dynamic trajectory generation. The real-time optimal trajectory is generated by the biologically inspired neural network, and the moving obstacle detection process of a ship robot working on the wall is simulated with the obstacle detection sensors models. The local real-time trajectory can be re-planned by the updated local map information, where the obstacle detection sensors are used to inspect partial environment information and update the robot nearby information in real time in the original neural network algorithm. At the same time, the method of the kinematic state templates matching and searching is used to solve the pipes’ influence of the rust removal robot climbing on the wall, which can not only provide a smooth path, but also can judge the motion direction and turning angle of the robot. Comparison of the proposed approach with the simulation shows that the improved algorithm is capable of planning a real-time collision-free path with achieving the local environmental information and judging the rust removal robot’s motion direction and turning angle. This proposed algorithm can be good used in the ship rust removal robot.     

基于BPF 的分布系统数字仿真方法

西南交通大学　电气工程学院　成都　610031      

一种新的异类多传感器系统误差融合估计算法

为解决由测向测时差无源被动传感器与主动传感器组网探测时异类多传感器系统误差估计问题,提出了一种新的异类多传感器系统误差融合估计算法.首先,通过对主被动传感器进行组合并构建异类传感器系统误差量测模型,实现了各组合传感器系统误差的实时估计;其次,通过建立多传感器融合估计结构,对多传感器系统误差的组合估计信息进行融合并反馈,获得了各传感器系统误差的全局融合估计.蒙特卡罗仿真结果表明:该算法能够对组网探测系统中各主、被动传感器的测向测时差及测距系统误差进行有效的融合估计,具有较高的工程应用价值.     

基于多种方位角计算方法的超短波AOA定位比较

考虑到方位角计算是AOA （angle of arrival）定位的基础之一，首先，提出了以大地坐标计算方位角的球面近似法和正轴圆柱投影-平面法；进而，建立了球面精确AOA定位方程、球面近似AOA定位方程和正轴圆柱投影-平面AOA定位方程；最后，采用无约束非线性规划方法建立了基于大地坐标的分别与上述方程相对应的3个最优化AOA定位模型，并以网格逐点搜索求解法进行了模型验证. 验证结果的分析表明:在不考虑测向误差时，球面精确AOA定位模型的精度最高，且与纬度无关，但其定位运算时间最长；球面近似AOA定位模型和正轴圆柱投影-平面AOA定位模型的精度均较高，后者的定位误差略大于前者，定位运算时间也长于前者；要提高AOA定位网的定位精度，既可提高各站点的测向精度，也可增加测向站点数，并应综合考虑定位时效性要求和精度要求选择合适的AOA定位模型.      

一种无线传感器网络抗虫洞攻击DV-HOP定位算法

为抵御虫洞攻击,改善定位性能,提出了一种基于安全邻居发现的抗虫洞攻击DV-HOP (distance vector-Hop)算法(secure neighbor discovery based DV-HOP, NDDV).该算法基于虫洞攻击时网络节点间通信跳数出现的异常,依据节点间路径跳数差异检测虫洞,通过搜索发现、滤除各虚假链路,以保障DV-HOP跳数跳距的准确性,减轻虫洞攻击的影响,提升节点定位精度.以变化参考节点比例的方式,对144个节点进行150次定位仿真实验,结果表明,平均节点度数达到5以上,NDDV即能有效滤除虫洞链路,提升节点定位精度;同等定位精度的情况下相比LBDV (label-based DV-HOP localization against wormhole attacks)算法所需的参考节点比例平均低约17.5%.      

Iris Localization Based on Edge Searching Strategies

An iris localization scheme based on edge searching strategies is presented. First, the edge detection operator Laplacian-of-Gaussian （LOG） is used to iris original image to search its inner boundary. Then, a circle detection operator is introduced to locate the outer boundary and its center, which is invariant of translation, rotation and scale. Finally, the method of curve fitting is developed in localization of eyelid. The performance of the proposed method is tested with 756 iris images from 108 different classes in CASIA Iris Database and compared with the conventional Hough transform method. The experimental results show that without loss of localization accuracy, the proposed iris localization algorithm is apparendy faster than Hough transform.     

基于频响函数的动车组构架传感器优化布置

为了实现传感器布置的位置和数量双重优化,提出了一种基于频率响应函数的传感器优化布置方法. 首先,对结构进行模态分析并提取模态振型,计算结构的频率响应函数;然后,基于独立分量分析和K-均值聚类法优化传感器布置位置;最后,计算不同传感器数量对应的布置结果的Fisher信息矩阵及其熵,信息熵的极小值对应的传感器数量即为传感器布置最优的数量. CRH3型动车组构架传感器优化布置结果表明,传感器均布置在符合国际铁路联盟标准UIC615-4规定的所有工况下构架产生最大应力位置附近,并且布置结果可以使数量有限的传感器获得的信息量最大化.      

An Improved Singularity Computing Algorithm Based on Wavelet Transform Modulus Maxima Method

IntroductionA recent finding is that noise signal may con-tain hidden information.Such information promis-es to be of application value(forecasting suddencardiac death in patients,or analyzing financialmarkets fluctuation,or predicting the properties ofelectric devices).We must use some approachesfor extracting such hidden information from noise.Conventional approaches include analysis ofmeans,standard deviations and other features ofhistograms,along with classical power spectrumanalysis.Thos…