Web图形技术与X3D的应用

Web图形技术包括二维矢量图形和三维图形.其中,X3D定义了如何在多媒体中整合基于网络传播的网络多媒体内容,及建立三维图形与交互多媒体的统一交换格式,并达到如HTML或XML的标准性或可扩展性.     

弹道导弹中段机动突防制导问题的仿真研究

对弹道导弹中段机动突防制导问题进行了仿真研究.完成了导弹高空机动突防系统概念设计,建立了大气层外飞行的导弹突防制导问题的数学模型,设计了非线性规划求解突防制导指令的两种算法:基于解析解的Bang-Bang控制形式求解和多重参数化法求解.最后基于以上数学模型和算法模型建立仿真系统,对突防制导问题的两种算法进行仿真验证.     

基于匈牙利算法的协同作战排序问题最优解

介绍了匈牙利算法,讨论了多目标空战中,将多个目标机分派给多攻击机进行攻击的排序问题,并利用匈牙利算法得到问题最优解.利用数值例子说明了求解过程.     

基于CPLD的多路数据采集系统

提出了一种基于CPLD的多路高速实时数据采集系统的新方法.该系统利用4片AD7655可以实现8通道同步采样或16通道异步采样,其中CPLD完成对A/D转换的逻辑控制,使用DSP21160对A/D转换数据进行处理.8路同步采样时最大采样频率可达700kHz,16路异步采样时最大采样频率可达350kHz.通过MAX+PLUSⅡ仿真及实际测试结果表明,所设计的基于CPLD的多通道数据采集系统,能够准确有效地进行A/D数据采集.     

硼酸-柠檬酸比色法测银杏枝叶中黄酮苷含量

用硼酸-柠檬酸比色法测定了银杏枝叶不同季节黄酮苷的含量,结果表明:硼酸-柠檬酸比色法测定银杏枝叶中的黄酮苷含量稳定性好,精度高,标准差为0.06,黄酮苷测定回收率为98.3%～101.1%,测定结果不受脂溶性杂质的干扰;银杏枝叶中的黄酮苷含量随季节的变化而变化,8月黄酮苷含量最高。     

Cooperative Transmissions in 5G Large-scale Relay Systems: How to Keep a Balance Between Performance and Complexity?

This paper presents a generalized i-vector representation framework with phonetic tokenization and tandem features for text independent as well as text dependent speaker verification. In the conventional i-vector framework, the tokens for calculating the zero-order and first-order Baum-Welch statistics are Gaussian Mixture Model (GMM) components trained from acoustic level MFCC features. Yet besides MFCC, we believe that phonetic information makes another direction that can benefit the system performance. Our contribution in this paper lies in integrating phonetic information into the i-vector representation by several extensions, forming a more generalized i-vector framework. First, the tokens for calculating the zero-order statistics is extended from the MFCC trained GMM components to phonetic phonemes, trigrams and tandem feature trained GMM components, using phoneme posterior probabilities. Second, given the zero-order statistics (posterior probabilities on tokens), the feature used to calculate the first-order statistics is also extended from MFCC to tandem feature, and is not necessarily the same feature employed by the tokenizer. Third, the zero-order and first-order statistics vectors are then concatenated and represented by the simplified supervised i-vector approach followed by the standard Probabilistic Linear Discriminant Analysis (PLDA) back-end. We study different token and feature combinations, and we show that the feature level fusion of acoustic level MFCC features and phonetic level tandem features with GMM based i-vector representation achieves the best performance for text independent speaker verification. Furthermore, we demonstrate that the phonetic level phoneme constraints introduced by the tandem features help the text dependent speaker verification system to reject wrong password trials and improve the performance dramatically. Experimental results are reported on the NIST SRE 2010 common condition 5 female part task and the RSR 2015 part 1 female part task for text independent and text dependent speaker verification, respectively. For the text independent speaker verification task, the proposed generalized i-vector representation outperforms the i-vector baseline by relatively 53 % in terms of equal error rate (EER) and norm minDCF values. For the text dependent speaker verification task, our proposed approach also reduced the EER significantly from 23 % to 90 % relatively for different types of trials.     

基于LS-SVM的机载天线伺服机构自适应控制

针对机载天线伺服机构运行时所受外力是快时变、变化范围大、且自身摩擦等非线性特性不能忽略的问题,提出一种基于最小二乘支持向量机(LS-SVM)的自适应控制设计方法。此方法将摩擦等非线性特性视为未知项,并利用LS-SVM在线估计被控对象的非线性未知项,从而设计得到LS-SVM的学习规则。系统运行结果证明:该方法能够很好地解决全范围内的系统稳定问题,并能在线跟踪任何光滑的输入信号,同时补偿摩擦等非线性特性,改善系统的动态品质和静态特性。     

Zone melting recrystallization of polysilicon by a focused-lamp with unsymmetric trapezoidal power distribution

Unsymmetric trapezoidal power distribution produced by a tungsten halogen lamp and a focusing mirror has been employed in zone-melting recrystallization of polysilicon. Focusing mirror is designed based on the ray-tracing method. Experimental results show that the trapezoidal type power distribution is superior to the Gaussian type which is obtained with a conventional strip heater, in that the controllability and reproducibility are significantly improved while the recrystallized film shows comparable or slightly better crystal quality. It has been found that a lower thermal gradient at the liquid-tosolid interface under a lower scan speed improves the quality of the recrystallized film prepared by the trapezoidal power distribution.     

Numerical investigation on spectral compression of femtosecond soliton in a dispersion-increasing fiber

The spectral compression performance of the fundamental soliton in a dispersion-increasing fiber is investigated through numerically solving the generalized nonlinear Schrödinger equation. Based on the calculation results, we detailedly analyze the influence of the input peak power, the fiber length, and the initial chirping on the output pulse, e.g. the spectral width, the spectral width ratio, and the center wavelength. The calculation results show that spectral compression from 12.6 nm to 5.2 nm, can be realized for the soliton with pulse width of 200 fs and center wavelength of 1550 nm propagating in the dispersion-increasing fiber with length of 100 m and the group-velocity dispersion parameter linearly varying from −1 ps²/km to −11 ps²/km.     

A Low Loss X-Band Quasi-Elliptic Ferroelectric Tunable Filter

A compact high quality factor four-pole X-band tunable quasi-elliptic bandpass filter is presented in this letter. The filter is enabled by high-Q ferroelectric barium strontium titanate capacitors and open-loop resonators. The central frequency of 8.35 GHz and the frequency tuning range of 500 MHz (6%) are achieved with a dc bias voltage of 30 V. The selective filter has a fractional 1 dB bandwidth ranging from 5.5% up to 7.3%. The measured insertion loss and return loss are 5.7-3.5 dB and 10.2-7.9 dB, respectively, with a dc bias range of 0 to 30 V. To the best of our knowledge, this is the best analog tunable performance and selectivity in X-band.