IRA码在体全息存储系统中的应用研究

在全息存储系统中,噪声分布是不均匀的,为了对存储的信息位进行不等保护,文中采用能纠不均匀错误的IRA码为系统的纠错码。通过高斯估计方法设计出适合全息存储系统的IRA码,并对其在系统中的应用进行了仿真,结果表明全息信道中IRA码的性能要远优于RS码。     

一种混合多边缘型LDPC码密度进化算法

在二进制输入加性高斯白噪声信道下,研究了基于多边缘型低密度奇偶校验码（Multi-edge Low Density Parity Check,MET-LDPC）的密度进化算法。针对高斯近似算法在前期迭代中的不准确问题,提出了一种改进算法。在分析MET-LDPC码的密度进化的基础上,将全密度进化与高斯近似算法结合,通过设置切换限制条件,弥补早期迭代的不准确,提高编码阈值估计的准确性。仿真结果表明,与MET-LDPC全密度进化算法相比,所提算法可以有效提高编码阈值估计的准确性,对LDPC编码的设计有一定的参考价值。     

单站两坐标雷达空间目标跟踪新算法研究

在以常规卡尔曼滤波器为基础的各种跟踪算法中，要求精确的模型和噪声统计，但在实际问题中，大多数情况上述要求不能满足。本文给出了考虑初始条件不精确性的改进型卡尔曼滤波算法，并在引入速度量测信息的基础上，运用该滤波方法进行空间目标二维定位。蒙特卡洛仿真表明该方法降低了对模型精度的要求，在工程上是可行的。     

利用光折射法的牛乳乳糖质量分数测量技术

为了快速准确测量牛乳乳糖成分,依据光折射理论,提出了牛乳乳糖质量分数的快速准确测量方法.牛乳乳糖溶液样品的获取、温度的影响、试样盒的形状是该测试方法的关键,根据测试要求和测量原理,进行了测试系统的硬件设计、制作和调试,依据乳糖溶液的浓度与CCD上记录的光斑位置存在唯一确定的函数关系,并利用测试系统进行了实验测量,证明了...     

数值积分的校正公式研究

讨论了积分校正公式的一般形式,利用代数精度的概念给出了确定了校正公式中的参数方法。给出了左矩形公式、梯形公式、辛甫生公式、一点高斯公式、二点高斯公式的校正公式,其它公式可类似处理。通过数值实例进行了比较。     

基于高斯混合带势概率假设密度滤波器的未知杂波下多机动目标跟踪算法

多模型的随机有限集(RFS)类方法是一类有效的多机动目标跟踪算法,但是现有算法都假定杂波统计特性先验已知,不适用于未知杂波背景。该文以高斯混合带势概率假设密度滤波器(GMCPHDF)为基础,提出一种未知杂波下的多机动目标跟踪算法。该算法对目标和杂波分别独立建模,通过最优高斯(BFG)估计方法对真实目标的强度函数进行预测,从而使多目标强度函数独立于机动目标的运动模型,实现各时刻真实目标的强度函数、杂波源期望个数以及真实目标和杂波源的混合势分布的迭代。仿真结果表明,该算法能够有效地联合估计多机动目标状态以及杂波期望个数。     

数字可调中频噪声源设计

介绍了用FPGA和AD9739产生可调中频噪声源的方法.采用Combined Tausworthe方法产生均匀分布,根据均匀分布和高斯分布之间的映射关系,使用折线逼近的方法产生基带的高斯分布.采用可配置HR IP核实现中心频率和带宽可调的中频噪声.FPCA产生的中频噪声源通过LVDS接口输出给AD9739.     

Recognizing jump patterns with physics-based validation in human moving trajectory

This paper presents an approach to recognize jump patterns in human moving trajectory, differentiating jump tracks from planar moving tracks. Since human moving trajectory is one of the most informative representations for content understanding and event detection, trajectory-based video analysis has been gaining popularity. However, a jump action typically leads to violent change in human moving trajectory, since the person suddenly leaves the original plane on which he/she has been moving. The abnormal tracks of the trajectory would influence the performance of trajectory-based video analysis. Hence, differentiating jump tracks from planar moving tracks is of vital importance, not to mention that jump actions typically imply significant events, especially in sports games. In this paper, volleyball videos are used as case study to demonstrate the effectiveness of our proposed jump pattern recognition approach. We derive player trajectory by head tracking, analyze the movement of each player, and recognize potential jump tracks in player trajectories based on two important characteristics: (1) jumps cause pulse-like tracks in the trajectory and (2) the extensions of such tracks go through the vanishing point of vertical lines in the scenes. Finally, the jump positions/heights are estimated, in addition to the planar moving trajectory of each player on the court ground. The experiments show that satisfactory results can be obtained with the proposed recognition scheme.     

An adaptive-weighted two-dimensional data aggregation algorithm for clustered wireless sensor networks

In this paper, an Adaptive-Weighted Time-Dimensional and Space-Dimensional （AWTDSD） data aggregation algorithm for a clustered sensor network is proposed for prolonging the lifetime of the network as well as improving the accuracy of the data gathered in the network. AWTDSD contains three phases： （1） the time-dimensional aggregation phase for eliminating the data redundancy; （2） the adaptive-weighted aggregation phase for further aggregating the data as well as improving the accuracy of the aggregated data; and （3） the space-dimensional aggregation phase for reducing the size and the amount of the data transmission to the base station. AWTDSD utilizes the correlations between the sensed data for reducing the data transmission and increasing the data accuracy as well. Experimental result shows that AWTDSD can not only save almost a half of the total energy consumption but also greatly increase the accuracy of the data monitored by the sensors in the clustered network.