A combination algorithm for MEMS hydrophone signal and noise separation北大核心CSCD

In the light of the problem of MEMS hydrophone data “submerged” in strong noise field, the combination filter of LMS adaptive noise cancellation and Fourier transform filtering is proposed. The filter algorithm is applied to MEMS hydrophone signal and noise separation. When the frequency of signal is given, the combination filter algorithm is used for signal extraction and the ideal signal performance comparison. Simulation results show that the effect of extraction resolution in strong noise field of -15 dB is higher in the algorithm. The algorithm can be used to search similar to the “black box” case. The filter is used to separate signal and noise in the Fen machine test of North University of China. The results show that the algorithm is efficient and Practicability. ©, 2014, The Editorial Office of Chinese Journal of Sensors and Actuators. All right reserved.     

Gibbs sampling based distributed OFDMA resource allocation

In this article, we present a distributed resource and power allocation scheme for muRip]e-resource wireless cellular networks. The global optimization of multi-cell multi-link resource allocation problem is known to be NP-hard in the general case. We use Gibbs sampling based algorithms to perform a distributed optimization that would lead to the global optimum of the problem. The objective of this article is to show how to use the Gibbs sampling （GS） algorithm and its variant the Metropolis-Hastings （MH） algorithm. We also propose an enhanced method of the MH algorithm, based on a priori known target state distribution, which improves the convergence speed without increasing the complexity. Also, we study different temperature cooling strategies and investigate their impact on the network optimization and convergence speed. Simulation results have also shown the effectiveness of the proposed methods.     

Sensor Placement for Sensing Coverage and Data Precision in Wireless Sensor Networks

We present a novel paradigm of sensor placement concerning data precision and estimation. Multiple abstract sensors are used to measure a quantity of a moving target in the scenario of a wireless sensor network. These sensors can cooperate with each other to obtain a precise estimate of the quantity in a real-time manner. We consider a problem on planning a minimum-cost scheme of sensor placement with desired data precision and resource consumption. Measured data is modeled as a Gaussian random variable with a changeable variance. A gird model is used to approximate the problem. We solve the problem with a heuristic algorithm using branch-and-bound method and tabu search. Our experiments demonstrate that the algorithm is correct in a certain tolerance, and it is also efficient and scalable.     

Community structure detection in social networks based on dictionary learning

Discovering community structures is a fundamental problem concerning how to understand the topology and the functions of complex network. In this paper, we propose how to apply dictionary learning algorithm to community structure detection. We present a new dictionary learning algorithm and systematically compare it with other state-of-the-art models/algorithms. The results show that the proposed algorithm is highly effectively at finding the community structures in both synthetic datasets, including three types of data structures, and real world networks coming from different areas.     

Theoretical Treatment of Target Coverage in Wireless Sensor Networks

The target coverage is an important yet challenging problem in wireless sensor networks,especially when both coverage and energy constraints should be taken into account.Due to its nonlinear nature,previous studies of this problem have mainly focused on heuristic algorithms;the theoretical bound remains unknown.Moreover,the most popular method used in the previous literature,i.e.,discretization of continuous time,has yet to be justified.This paper fills in these gaps with two theoretical results.The first one is a formal justification for the method.We use a simple example to illustrate the procedure of transforming a solution in time domain into a corresponding solution in the pattern domain with the same network lifetime and obtain two key observations.After that,we formally prove these two observations and use them as the basis to justify the method.The second result is an algorithm that can guarantee the network lifetime to be at least (1-ε) of the optimal network lifetime,where e can be made arbitrarily small depending on the required precision.The algorithm is based on the column generation(CG) theory,which decomposes the original problem into two sub-problems and iteratively solves them in a way that approaches the optimal solution.Moreover,we developed several constructive approaches to further optimize the algorithm.Numerical results verify the efficiency of our CG-based algorithm.     

Robust RBPF for mobile robot using panoramic vision

We present a novel vision-based approach to self-localization that uses an improved scheme to integrate feature-based matching of panoramic images with a Rao-Blackwellized Particle Filter （RBPF） for mobile robot Simultaneous Localization and Mapping （SLAM）. The matching for SIFT multi-dimension features is implemented with a KD-tree which introduce the Mahalanobis distance instead of the Euclidean distance for matching features. The particle filter is combined with Gaussian Mixture Unscented Particle Filters （GMUPF） to for initializing landmarks and a Single-Cluster Graph-Partitioning algorithm for outlier rejection. The landmark position estimation and update is also implemented through GMUPF by which a single update step from moving and sensing can be done and the change to the map certainty can be done in constant time. Experiment results on real robot in our indoor environment show the advantages of our methods over previous approaches.     

A differential evolutionary based algorithm for multiuser OFDMA system adaptive resource allocation

In this paper, the problems of radio resource allocation for Orthogonal Frequency Division Multiple Access （OFDMA） systems are addressed. The main goal of this paper is to present and analyze base station allocation of subcarriers and adaptive modulation. We impose a set of proportional fairness constraints to assure that each user can achieve a required data rate. Since the optimal solution to the fairness problem is extremely computationally complex to obtain, we propose an adaptive radio resource allocation method based on differential evolutionary algorithm for multiuser OFDMA system. The performance of the described schemes is further evaluated in numerical experiments. We improve the convergence of the differential evolutionary algorithm through the method of elitist selection and adding some individuals with ＇good＇ genes to the initial population. Simulation results show that out proposed algorithm better than static subcarrier allocation schemes TDMA in muhiuser OFDMA system.     

Target tracking based on the extended H-infinity filter in wireless sensor networks

In this paper, we propose a new target tracking approach for wireless sensor networks (WSNs) by using the extended H-infinity filter. First, the extended H-infinity filter for nonlinear discrete-time systems is deduced through the Krein space analysis scheme. Then, the proposed extended H-infinity filtering algorithm is applied to target tracking in wireless sensor networks. Finally, experiments are conducted through a small wireless sensor network test-bed. Both experimental and simulation results illustrate that the extended H-infinity filtering algorithm is more accurate to track a moving target in wireless sensor networks than using the extended Kalman filter in the case of having no knowledge of the statistics of the environment and the target to be tracked.     

基于多传感融合的路面机动目标跟踪

Maneuvering targets tracking is a fundamental task in intelligent vehicle research. This paper focuses on the problem of fusion between radar and image sensors in targets tracking. In order to improve positioning accuracy and narrow down the image working area, a novel method that integrates radar filter with image intensity is proposed to establish an adaptive vision window. A weighted Hausdorff distance is introduced to define the functional relationship between image and model projection, and a modified simulated annealing algorithm is used to find optimum orientation parameter. Furthermore, the global state is estimated, which refers to the distributed data fusion algorithm. Experiment results show that our method is accurate.     

A distributed algorithm for multi-region problem in BEM

The situation of multi-region problem may oftem appear when boundary element method(BEM)is applied in practical problems especially in VLSI-CAD.It is difficult to deal with this problem if traditional methods are used.Particularly. when the problem to be solved contains a lot of materials,the advantages of using BEM such as simplicity,convenience and rapidity will be weakened due to the complexity of solving complex boundary element equation.In this paper a distributed algorithm for multi-region problem in BEM is presented.This algorithm has been implemented in a distributed system consisting of 3 workstations to extract VLSI layout parameters.The results show that the calculation time of this distributed algorithm is less than that of the traditional methods.The results also demonstrate that this algorithm can speed up the computation and has the features of parallelism and high efficiency.     

跟踪遮挡目标的一种鲁棒算法

为了解决在跟踪目标过程中的遮挡问题,引入Kalman滤波器为Mean Shift跟踪算法选择初始点,在跟踪稳定的情况下进行模型更新以消除由于目标缓慢变化而产生的累积误差对跟踪结果的影响。根据Kalman滤波器残差的大小判定是否发生遮挡,遮拦检测算法对目标进行分块检测从而把遮挡分为部分遮挡和完全遮挡两种情况,并对两种情况进行区别讨论：对部分遮挡情况不做特殊处理;对完全遮挡情况,结合目标的运动方向提出6点搜索策略来找回目标。实验表明,该算法能很好地解决跟踪运动目标过程中目标的遮挡问题。     

灰度与速度线索融合红外小目标跟踪

红外小目标跟踪易受到相似目标与背景的干扰,针对此问题提出一种融合灰度与速度线索的红外小目标跟踪算法。该算法通过快速时域高通滤波器滤除噪声并突出目标,利用主分量分析提取速度特征;以分层粒子滤波为框架,首先利用高通滤波图像灰度核函数加权直方图进行第1层粒子滤波,粗略地估计目标状态;然后利用速度线索进行第2层粒子滤波,精确地估计目标状态。实验结果表明,提出的红外小目标跟踪算法具有较强的抗干扰性能和较高的跟踪精度。     

粒子滤波在无线传感器网络目标跟踪中的应用

将粒子滤波（PF）算法应用于无线传感器网络（WSNS）的目标跟踪,并给出了粒子滤波实现的具体步骤。动态组织传感器网络节点成簇,实现了对网络中做匀速直线运动的单个目标的跟踪。分别采用扩展卡尔曼滤波（EKF）、无迹卡尔曼滤波（UKF）和PF算法进行了仿真试验。结果表明,在无线传感器网络目标跟踪领域,PF算法比EKF算法、UKF算法的滤波精度更高,性能更好,并且在实际应用中,由于该算法能够有效解决非线性、非高斯环境中的目标跟踪问题,实现简单而增强了可用性。     

具有慢速时滞机动目标三维跟踪

目标运动状态模型的建立是机动目标跟踪的关键问题．本文首先通过对目标加速度的运动建模．建立了具有时滞的目标状态运动学模型．然后,应用H∞滤波算法进行了跟踪．大射电望远镜50 m模型实验结果表明馈源舱在恒定速率运动的条件下,本文算法显著提高了徕卡(Leica)的测量精度．     

Interacting multiple model and sensor selection algorithms for manoeuvring target tracking in wireless sensor networks with multiplicative noise

This article addresses the problem of tracking a manoeuvring target in a wireless sensor network (WSN) consisting of distance-measuring sensor nodes. In order to cope with target manoeuvres, an interacting multiple model (IMM) filter is applied to estimate the position and velocity of the target. The distance-dependent measurement error of sensors is formulated as both additive and multiplicative noise in the observation equation. To deal with nonlinearities in the process and observation equations and also to solve the problem of multiplicative measurement noise, a new particle filter (PF)-based IMM approach is developed. Furthermore, the multiple-model posterior Cramér-Rao lower bound (PCRLB) is derived in the presence of both additive and multiplicative noise and it is used to perform a sensor selection algorithm to reduce energy consumption in WSN nodes. Simulation results show the effectiveness of the proposed IMMPF and sensor selection algorithms in target tracking.     

结合Kalman滤波器的Mean-Shift跟踪算法

针对经典Mean-Shift算法要求相邻两帧间目标模板区域必须重叠的缺陷,结合Kalman滤波器,提出了改进算法。算法首先将Kalman滤波器预测的目标位置作为Mean-Shift算法中的初始搜索中心进行跟踪,然后再将Mean-Shift算法得到的新的目标位置作为下一帧Kalman滤波器的输入参数,循环执行。实验证明,该算法能够解决由于目标运动速度突然变化以及目标快速运动情况下所带来的相邻两帧间目标模板区域非重叠问题,而且对于一般的遮挡问题也能得到较好的效果。     

面向量测的◢m-最优N◣扫描多假设跟踪方法

为解决联合概率数据互联只能跟踪已知数目目标和互联模糊,以及传统多假设跟踪算法生成假设数目随时间积累呈指数增长问题。提出一种面向量测m-最优假设N扫描MHT方法。首先,在每一假设下生成m-最优假设,在每帧产生既定数目最优及次优假设;然后,通过N宽度滑窗产生最优可行假设,完成数据互联,并分别使用两点差分线性法和全局最小二乘估计完成单个新目标和多个新目标航迹起始。仿真结果表明,该方法与MHT-DAM算法相比较,获得了跟踪性能和运算时间上的平衡。     

融合帧间差分与碰撞算法的快速跟踪预测算法

传统的运动目标跟踪预测算法难以保证机器人对高速运动目标的快速捕捉和提前预测,尤其是运动目标在滑行过程中发生碰撞改变了原有的运动方向,针对这一问题提出了基于帧间差分与碰撞算法相结合的运动目标跟踪预测算法.通过帧间差分法快速识别出平面内运动物体的具体位置和运动速度,根据其运动速度方向判别运动目标是否发生碰撞.当运动目标在运动过程中发生碰撞,采用LS-DYNA显示动力分析软件建立碰撞仿真模型,并用MATLAB拟合仿真数据得到碰撞算法,结合碰撞算法对运动目标的运动轨迹进行预测.结果表明以帧间差分和碰撞算法相结合的运动目标检测跟踪算法对于在平面内运动目标的跟踪预测方面速度更快,完全能够满足机器人对算法快速性的要求.     

仅有角测量的被动式机动目标跟踪

以往的被动式跟踪研究往往假定目标作匀速直线运动, 采用目标与跟踪站的相对距离和速度为状态变量, 因而相应的跟踪滤波器不能跟踪机动目标. 研究了仅有角测量的机动目标跟踪问题, 采用目标的位置、速度及加速度作为状态变量, 并对测量方程进行适当变换, 推导出一种伪线性机动目标自适应跟踪算法, 可用于单站或多站被动式机动目标跟踪. 大量的仿真研究表明了本算法的有效性, 其中多站跟踪比单站跟踪具有更高的精度、算法稳定性和快速收敛性.