Evolutionary circuit design for fast FPGA-based classification of network application protocols

The evolutionary design can produce fast and efficient implementations of digital circuits. It is shown in this paper how evolved circuits, optimized for the latency and area, can increase the throughput of a manually designed classifier of application protocols. The classifier is intended for high speed networks operating at 100 Gbps. Because a very low latency is the main design constraint, the classifier is constructed as a combinational circuit in a field programmable gate array (FPGA). The classification is performed using the first packet carrying the application payload. The improvements in latency (and area) obtained by Cartesian genetic programming are validated using a professional FPGA design tool. The quality of classification is evaluated by means of real network data. All results are compared with commonly used classifiers based on regular expressions describing application protocols.     

人机交互中的声源定位与增强方法

基于人机交互的实际应用场景,提出了一种交互目标声源三维定位与语音增强算法。该算法首先在广义相关法的基础上提出一种声达时延差的估计方法,通过由6个麦克风构成的平行均匀线阵接收模型,实现对目标声源的三维定位;然后在交互目标声源定位的基础上,通过调整时延波束叠加的权值,实现对目标语音的增强。仿真实验结果表明,文中提出的算法能够准确定位目标声源并对目标语音进行有效增强。在信噪比大于1.5 dB 的环境中,该算法可使目标声源达到98%以上定位精度,5 dB 以上信噪比改善,同时算法运算量小且易于硬件实现。     

Design of a printed log‐periodic dipole array antenna with high gain for millimeter‐wave applications

In this article, a V‐band printed log‐periodic dipole array (PLPDA) antenna with high gain is proposed. The antenna prototype is designed, simulated, fabricated, and tested. Simulation results show that this antenna can operate from 42 to 82 GHz with a fractional impedance bandwidth of 64.5% covering the whole V‐band (50–75 GHz). The antenna has a measured impedance matching bandwidth that starts from 42 to beyond 65 GHz with good agreement between the experimental and simulated results. At 50 and 65 GHz, the antenna has a measured gain of 10.45 and 10.28 dBi, respectively, with a gain variation of 2.6 dBi across the measured frequency range. The antenna prototype exhibits also stable radiation patterns over the operating band. It achieves side‐lobe suppression better than 17.26 dB in the H‐plane and better than 8.95 dB in the E‐plane, respectively. In addition, the cross‐polarization component is 18.5 dB lower than the copolarization with front‐to‐back ratio lower than 24.1 dB in both E‐ and H‐planes across the desired frequency range. Based on a comparison of performance among the reported work in the literature, we can say that the proposed PLPDA antenna is a proper candidate to be used in many applications at V‐band frequency. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:185–193, 2015.     

Novel ultra‐compact two‐dimensional waveguide‐based metasurface for electromagnetic coupling reduction of microstrip antenna array

A novel ultracompact two‐dimensional (2D) waveguide‐based metasurface is proposed herein and applied for the first time to reduce mutual coupling in antenna array for multiple‐input multiple‐output applications. The unit cell of the proposed 2D waveguide‐based metasurface is ultracompact (8.6 mm × 4.8 mm, equal to λ₀/14.2 × λ₀/25.5) mainly due to the symmetrical spiral lines etched on the ground. The metasurface exhibits a bandgap with two transmission zeros attributing to the negative permeability in the vicinity of magnetic resonance and the negative permittivity in the vicinity of electric resonance. Taking advantage of these two features, a microstrip antenna array is then designed, fabricated, and measured by embedding an 8 × 1 array of the well‐engineered 2D waveguide‐based metasurface elements between two closely spaced (9.2 mm, equal to λ₀/13.3) H‐plane coupled rectangular patches. There is good agreement between the simulated and measured results, indicating that the metasurface effectively reduces antenna mutual coupling by more than 11.18 dB and improves forward gain. The proposed compact structure has one of the highest reported decoupling efficiencies among similar periodic structures with comparable dimensions. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:789–794, 2015.     

海量数据处理器MPC860T的DSP阵列设计

现代通信的数据量日益增加,数据处理的复杂度也日益加强,如何有效处理这些海量数据,是目前研究的难点,基于DSP阵列的数据处理系统是解决这些问题的有效方法。本文选用TI公司的TMS320C6713浮点型数字信号处理器以及Freescale公司的MPC860T通用通信处理器,设计了16颗浮点型DSP阵列来完成海量数据实时处理。详细介绍了该系统的DSP阵列的管理,包括复位、HPI数据管理通道设计。通过测试和实际应用验证,该系统不仅满足性能上的要求,还是一个通用的数据采集和处理平台。     

一种高增益宽频带圆极化微带阵列天线的研制

针对微带天线阻抗匹配带宽一般较窄的自身缺陷,基于相控阵雷达天线的应用背景,设计了一种工作在X波段的双层圆极化微带天线结构,且优化发现,其各电磁参数良好。为提高其增益,还在此基础上设计并最终制作了双层2×2结构的微带天线阵列,其实测性能与设计值相符,增益达到10.7dB,带宽1.2GHz,相应轴比为4dB,符合圆极化要求。     

Bacteria foraging optimization in antenna engineering: An application to array fault finding

Finding fault elements in linear antenna arrays using bacteria foraging optimization (BFO) is presented. One of the better options of array diagnosis is to perform it by measuring the radiated field, because in this case, removal of the array from its working site is not required and thereby not interrupting its normal operation. This task of fault finding from far‐field data is designed as an optimization problem where the difference between the far‐field power pattern obtained for a given configuration of failed element(s) and the measured one is minimized w. r. t. the excitations of the array elements. This set of excitations on comparison with the excitations of the original array gives the idea of the fault position and their type, such as either complete fault or partial fault. BFO being relatively new to microwave community when compared with other soft‐computing techniques, its performance was observed w. r. t. time of computation and convergence of the iterative process. Possibility of finding the faults from random sample points and use of minimum number of sample points for array fault finding are the novelties of the present work. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

汉江兴隆水利枢纽一期土石围堰二维渗流分析

汉江兴隆水利枢纽一期土石围堰坐落在50~60 m深的覆盖层上,覆盖层上层为厚15~30 m粉细砂、含泥粉细砂层,抗渗稳定性差,下层为30余m厚的砂砾石层,透水性大。围堰防渗采用塑性混凝土防渗墙上接复合土工膜心墙方案。为了解方案的防渗效果,采用二维稳定渗流模型和理正渗流分析软件,计算比较了不同防渗墙深度对应的渗透出逸比降和单宽渗流量。结果表明,悬挂式防渗墙不能有效控制渗透出逸比降和渗流量,与下部相对不透水层接触的着底式防渗墙渗流控制效果显著。     

基于双机热备的瓦斯灾害预警系统设计

针对煤矿瓦斯灾害预警系统软硬件运行环境的单点失效问题,设计了一种基于双机热备的瓦斯灾害预警系统,介绍了该系统的双机热备方案、软硬件结构设计及实现方法。该系统选用互备运行模式的双机备份高可用性集群及基于RoseHA和共享磁盘阵列的双机热备方案,提高了系统的可靠性。应用结果表明,与单服务器的预警系统相比,基于双机热备的瓦斯灾害预警系统的平均无故障间隔时间大幅增加,平均故障修复时间大大缩短,系统可用性有了较大提高。     

基于数学形态学边缘检测的车牌字符分割算法

汽车牌照字符分割是车牌识别过程中的关键步骤,直接影响到字符识别的效果。传统的方法对车牌图像质量要求较高,且抗干扰能力较差。提出一种基于Renyi熵和数学形态学边缘检测的车牌字符投影分割算法,首先用二维Renyi熵最大阈值法对车牌图像做二值化处理,然后用形态学腐蚀运算进行边缘检测,再去除车牌边框,最后通过投影分割提取车牌字符。仿真实验表明,基于Renyi熵最大阈值法和数学形态学边缘检测车牌图像预处理使得车牌字符边缘清晰,降低了噪声的干扰,有利于进行字符投影分割。该算法分割速度快,鲁棒性好,可获得比传统方法更好的分割效果。