FloatBag选择性神经网络集成及其在人脸检测中的应用

神经网络集成利用多个神经网络对同一个问题进行学习,集成在某输入示例下的输出由构成集成的各神经网络在该示例下的输出共同决定.本文提出利用FloatBag的方法择优选择个体神经网络,进而用平均值的方法组合各个体网络.最后,我们将FloatBag方法应用于多角度人脸检测中.实验证明,这种方法优于一般的神经网络集成方法.     

A study on photo-induced intramolecular electron-transfer in fullerene-benzothiadiazole-triphenylamine using time-dependent density functional theory

We employed first-principle calculations to study the photo-induced electron transfer (PIET) process of a fullerene-benzothiadiazole-triphenylamine (C60-BTD-TPA), fullerene-diphenylbenzothiadiazole-triphenylamine (C60-PBTD-TPA), and fullerene-triphenylamine (C60-TPA). The ground state geometries of C60-BTD-TPA, C60-PBTD-TPA, and C60-TPA were optimized using density functional theory (DFT). Their excited states were investigated using time-dependent HF, and time-dependent DFT (TDDFT) methods. The long-range corrected CAM-B3LYP functional was found to give the best agreements with the experimentally observed transition energies. CAM-B3LYP-based wave functions were also employed to calculate the charge transfer integrals using generalized Mulliken–Hush (GMH) approach, and the photo-induced charge separation (k_CS) and charge recombination rate constants (k_CR) were calculated using Marcus theory. The results showed the calculated k_CS and observed k_CS of C60-PBTD-TPA and C60-TPA correspond to each other, however, the both of C60-BTD-TPA differ by two orders of magnitude. For k_CR of these compounds, the calculated and observed values were more contrary to each other due to improper application of Marcus electron-transfer theory.     

某火炮膛口流场数值仿真

用Osher格式求解三维、可压缩流动方程组,计算和分析了某火炮膛口气流现象.在建立差分算法时,将有限体积离散和黎曼解算器相结合,简化了计算工作.首先,以楔形风洞中马赫数为Ma∞=2.0的超音速流动问题开展数值实验,数值结果与理论值吻合很好;其次,计算了火炮膛口气流问题,取得包括炮车表面等位置的膛口全流场的流动参数分布,数值结果较详细地描述了此气流发展过程.     

基于因特网的液压系统远程控制的基础研究

本文以液压系统为被控对象,对在因特网环境下的远程控制系统提出了具有挑战性的研究.仿真及实验结果表明,采用适当的补偿器结构和时延预测算法可以比较好地解决因特网在传递控制信息时的时延及时延的不确定性对液压远程控制系统的影响,使采用因特网的机械运动的远程控制成为可能.本文还提出了实现这种远程控制时需要对远程端采样信息进行适当的处理;为保证在相同的网络条件下进行实验研究,需要构筑能对因特网网络时延及时延的不确定性进行再现的因特网远程控制实验系统.     

改进的正弦波拟合法评价数据采集系统通道间延时

针对正弦波拟合法的缺陷,介绍了一种新的方法来评价高速同步数据采集系统通道间延时,即多谐波正弦拟合法。讨论了评价过程的误差来源,同时给出了评价过程的计算机仿真,并比较了两种方法估计正弦信号初相的优劣。仿真结果表明,多谐波正弦拟合法相对于正弦波拟合法有更好的测量精度,并降低了信号源谐波失真及频率误差带来的影响。     

Detection Probability Estimation of Directional Antennas and Omni-Directional Antennas

This paper studies the problem of detection of directional antennas and omni-directional antennas by hostile detection systems. We present a model for calculating the probability of detecting a transmitter at arbitrary location around the transmitter. Our study shows that, if a directional antenna employs the same transmit power as an omni-directional antenna, the directional antenna can not decrease the probability of being detected. In some scenarios, a directional antenna is more likely to be detected than an omni-directional antenna. However, if a directional antenna provides the same Effective Isotropic Radiated Power in the direction of the receiver as an omni-directional antenna, the transmit power needed by a directional antenna to send data is much less than that of an omni-directional antenna. In this scenario, the probability of detecting a directional antenna is reduced by over 90%. This reveals that directional antennas can be used to build a secure path to send data at low probability of being detected by adversaries.     

弹载捷联惯导系统空中传递对准精度评估

弹载捷联惯导系统空中传递对准是机载战术导弹发射前必须完成的任务,其对准精度直接影响导弹系统的制导精度。但传递对准误差无法直接测量,使其评估成为一个难题。文中提出以载机主惯导为参考系统,以主子惯导系统的速度差和位置差作为观测量,采用固定点平滑和固定区间平滑滤波的评估方案。利用Matlab/Simulink建立评估仿真平台,得出仿真结果。分析结果表明,该方案是可行的。     

一种消除杆臂挠曲运动影响的传递对准方法

正确消除飞行器杆臂挠曲运动的不利影响是提高惯导系统传递对准性能的关键技术之一.文中在继承速度积分匹配方法优点的基础上,提出一种平均速度匹配传递对准方案,能够有效降低杆臂的挠曲运动对速度匹配传递对准精度和滤波稳定性的影响.通过在线计算滤波器的系统噪声矩阵Q,避免了飞行器杆臂挠曲运动建模的问题.系统仿真结果表明,该传递对准方案能够提高滤波器的稳定性,并对杆臂挠曲运动进行有效抑制.     

Improved low-distortion sigma-delta ADC with DWA for WLAN standards

An improved low distortion sigma-delta ADC(analog-to-digital converter) for wireless local area network standards is presented.A feed-forward MASH 2-2 multi-bit cascaded sigma-delta ADC is adopted;however,this work shows a much better performance than the ADCs which have been presented to date by adding a feedback factor in the second stage to improve the performance of the in-band SNDR(signal to noise and distortion ratio),using 4-bit ADCs in both stages to minimize the quantization noise.Data weighted ...     

High-speed low-power voltage-programmed driving scheme for AMOLED displays

A new voltage-programmed driving scheme named the mixed parallel addressing scheme is presented for AMOLED displays, in which one compensation interval can be divided into the first compensation frame and the consequent N-1 post-compensation frames without periods of initialization and threshold voltage detection. The proposed driving scheme has the advantages of both high speed and low driving power due to the mixture of the pipeline technology and the threshold voltage one-time detection technology. Corresponding to the proposed driving scheme, we also propose a new voltage-programmed compensation pixel circuit, which consists of five TFTs and two capacitors(5T2C). In-Zn-O thin-film transistors(IZO TFTs) are used to build the proposed 5T2C pixel circuit. It is shown that the non-uniformity of the proposed pixel circuit is considerably reduced compared with that of the conventional 2T1C pixel circuit. The number of frames(N) preserved in the proposed driving scheme are measured and can be up to 35 with the variation of the OLED current remaining in an acceptable range. Moreover, the proposed voltage-programmed driving scheme can be more valuable for an AMOLED display with high resolution, and may also be applied to other compensation pixel circuits.