低功耗数字控制超长波发射与接收系统

针对管道、矿山和水下等特殊环境中的信息通讯与信号传输等问题,根据超长波(ELF Electromagnetic Wave)具有传播损耗小且相位稳定等特点,给出了超长波发射与接收系统的设计原理与实现过程.发射系统采用单片机控制,输出的信号经发射天线产生23 Hz超长波,接收系统对采集到的信号进行带通滤波及放大处理.工程实验表明,所设计的系统在锂电池供电状态下,具有发射功耗低(连续工作时间大于72 h)、发射功率大(传播距离大于10 m)、且对接收的信号处理快速可靠(动态时滞小于5 s)等优点.     

Synthesis of symmetric and asymmetric singly terminated elliptic ladder filters for multiplexing applications

An extension of the Cauer ladder development for synthesizing singly terminated filters with symmetric and asymmetric responses is presented. Basically, a driving‐point immittance including reactive constant elements is carried out in such a way that provides the transmission zeros. The reactive constant elements are introduced into the synthesis for two reasons. The first is to consider the possibility of the asymmetric position of transmission zeros in the real frequency axis. The second one is to obtain canonical forms, i.e. networks with the minimum number of elements in the case of symmetrical responses. To validate the proposed method, a filter with asymmetrical response has been synthesized, comparing different topologies for its use in multiplexers. This fact is illustrated with a Ku‐band elliptic response diplexer designed in H‐plane rectangular waveguide. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

Technology for simulating crowd evacuation behaviors

This paper presents a model for simulating crowd evacuation and investigates three widely recognized problems. For the space continuity problem, this paper presents two computation algorithms: one uses grid space to evaluate the coordinates of the obstacle's bounding box and the other employs the geometry rule to establish individual evacuation routes. For the problem of collision, avoidance, and excess among the individuals, this paper computes the generalized force and friction force and then modifies the direction of march to obtain a speed model based on the crowd density and real time speed. For the exit selection problem, this paper establishes a method of selecting the exits by combining the exit's crowd state with the individuals. Finally, a particle system is used to simulate the behavior of crowd evacuation and produces useful test results.     

A new SQP algorithm based on semidefinite programming

The paper gives a new filter-SQP algorithm of the semidefinite programming through combining the sequence nonlinear algorithm of solving the semidefinite programming, low rank conversion, and filter method, which, under certain conditions, proves that the algorithm is global convergence.     

改进的粒子群算法

针对基本粒子群算法容易陷入局部最优点,进化后期速度慢等缺点,设计了一种新的粒子群算法,将基本粒子群算法粒子行为基于个体极值点转化为个体自身极值与其他某一个个体极值的加权平均值,而全局极值点转化为群体中优秀个体极值的加权平均值。数值仿真实验表明,新算法比PSO具有更好的收敛性,能更快地找到问题的最优解。     

中文网页内容柔性过滤器的研究与实现

不法分子为了逃避过滤,将不良信息中的敏感关键词进行变形。为了识别这些变形的关键词,提出了一种柔性过滤算法。在此基础上,利用浏览器帮助对象（BHO）,构建了一个中文网页内容柔性过滤器,用于实时过滤由变形关键词生成的不良网页。该过滤器改善了传统过滤器不能过滤变形关键词的现状,是对传统的基于关键词过滤方法的补充。     

Cryo-EM image alignment based on nonuniform fast Fourier transform

In single particle analysis, two-dimensional (2-D) alignment is a fundamental step intended to put into register various particle projections of biological macromolecules collected at the electron microscope. The efficiency and quality of three-dimensional (3-D) structure reconstruction largely depends on the computational speed and alignment accuracy of this crucial step. In order to improve the performance of alignment, we introduce a new method that takes advantage of the highly accurate interpolation scheme based on the gridding method, a version of the nonuniform fast Fourier transform, and utilizes a multi-dimensional optimization algorithm for the refinement of the orientation parameters. Using simulated data, we demonstrate that by using less than half of the sample points and taking twice the runtime, our new 2-D alignment method achieves dramatically better alignment accuracy than that based on quadratic interpolation. We also apply our method to image to volume registration, the key step in the single particle EM structure refinement protocol. We find that in this case the accuracy of the method not only surpasses the accuracy of the commonly used real-space implementation, but results are achieved in much shorter time, making gridding-based alignment a perfect candidate for efficient structure determination in single particle analysis.     

Adaptive IIR/FIR fusion filter and its application to the INS/GPS integrated system

Motivated by the complementary features of the IIR-type filter and the FIR-type filter, this paper proposes a robust IIR/FIR fusion filter and an INS/GPS integrated system designed with the fusion filter. In the fusion filter, an IIR-type filter (SPKF) and a FIR-type filter (MRHKF filter) are processed independently, and then the two filters are merged using the mixing probability calculated using the residuals and residual covariance information of the two filters. The merits of the SPKF and the MRHKF filter are integrated and the demerits of the filters are diminished through the filter fusion. Consequently, the proposed fusion filter shows robustness against model uncertainty, temporary disturbing noise, large initial estimation error, etc. The stability of the fusion filter is verified by showing the closeness of two filters in the mixing/redistribution process and the upper bound of the error covariance matrices. This fusion filter is applied to an INS/GPS integrated system. The performance of the INS/GPS integrated system designed using the fusion filter is verified through a simulation under various error environments and is experimentally confirmed.     

基于视频序列的火焰模拟

在现有火焰模拟方法的基础上,提出了基于视频序列的火焰模拟方法.该方法首先用火焰视频帧图像提取火焰边界,然后用提取出来的边界对火焰形状建模,并在相邻模型间进行线性插值,获得火焰燃烧过程的形状变化3D动态模型,最后用粒子系统模拟,给出了具体的模拟步骤和实际的模拟效果.     

一种新的半监督入侵检测算法

针对无监督学习的入侵检测算法准确度不高、监督学习的入侵检测算法训练样本难以获取的问题,提出了一种粒子群改进的K均值半监督入侵检测算法,利用少量的标记数据生成正确样本模型来指导大量的未标记数据聚类,对聚类后仍未能标记的数据采用粒群优化的K均值聚类,有效提高分类器的分类准确性,并实现了对新类型攻击的检测。实验结果表明,算法的整体检测效果明显优于基于无监督学习和监督学习的检测算法。