基于SIFT特征匹配算子的三维重建方法研究

为了改善基于双目立体视觉的逆向工程中零件三维重建的精度,提出了一种基于尺度不变特征变换(SIFT)算子的三维重建方法.该方法通过SIFT算子搜索得到两幅对应的数字图像中的匹配特征点,并利用标定好的摄像机参数将图像特征点映射成空间直线,最后采用异面直线公垂线中点逼近法求取三维空间点的坐标.该方法不需要额外的设备来辅助特征点的匹配,实验结果表明该方法具有良好的鲁棒性.     

车载环境下基于样本熵的语音端点检测方法

在语音处理中一个关键性问题是如何准确找到语音的起止位置,目前提出许多的语音端点检测算法不能得到理想的检测结果.由于样本熵是近似熵的改进算法,提出车载环境下基于样本熵的语音端点检测方法.并采用模糊C均值聚类算法和贝叶斯信息判决算法进行样本熵特征门限估计,以及使用双门限法进行语音端点检测.在TIMIT连续语音库上的实验表明,车载噪声环境下,样本熵法和近似熵法的检测正确率均远高于谱熵法和能量谱熵法,而样本熵法相对于近似熵法具有更好的检测效果,特别是当信噪比小于等于OdB时,样本熵法的检测性能优于近似熵法近10%.因此,样本熵法在车栽智能语音领域具有很好的应用前景,能够为车载导航提供准确的语音端点检测技术.     

通用鱼雷模拟器适应性软件开发

提出一种具有动态重配置功能的分布式仿真系统成员适应性软件构架,开发通用鱼雷模拟器的适应性软件,它由接口通信层、需求管理层、适应性重配层以及功能实现层构成,给出软件开发所需的关键技术,包括动态重配引擎、可配置化构件模型与功能构件库。利用该通用鱼雷模拟器适应性软件进行实例测试,结果验证了其可行性与有效性。     

一种基于最小均方误差原理的位同步捕捉算法

提出一种数字通信系统中基于最小均方误差原理的位同步捕捉算法,对算法的提出、原理以及性能进行了理论分析,同时在加性高斯白噪声信道下进行了大量的计算机仿真,给出了在某无线通信系统中的应用结果.此算法通用性强,实现位同步捕捉速度快,易于高速单片机及DSP实现,具有良好的抗噪性能.     

归一化算法在文字识别系统中的应用研究

针对汉字图像预处理过程中归一化算法进行了改进.先对单个汉字进行大小归一化,并在此基础上对汉字进行细化,最后对骨架图像进行修正.实验结果表明该算法有效可行,可应用于汉字识别的后续处理.     

Profibus-DP数据显示从站设计

用于设备级控制系统与分散式I/O通信的Profibus-DP是市场占有率绝对领先的总线技术.设计了一种基于西门子的SPC3的Profibus-DP的数据显示智能从站,详细分析了从站的硬件及软件结构,研究并解决了RS485通信现场设备与Profibus-DP现场总线通信问题.测试实验采用基于PC加软PLC构成Profibus-DP 1类主站,数据显示单元做从站,通过在PC机上监控Profibus通信报文的方法,成功验证了此显示单元模块能和西门子的设备进行互连,符合Profibus-DP标准.     

一种认知无线电网络接入控制和功率控制联合设计

在underlay频谱共享模式下,提出一种认知无线电网络接入控制和功率控制的联合算法。该算法针对主用户干扰温度和次用户信号干扰噪声比(SINR)限制,通过引入冲突因子,实现网络自适应调整被拒绝参与频谱共享的次用户数目,通过迭代进行接入控制和功率分配实现频谱共享。仿真结果表明,该算法能够保证接入共享主网络频带的次用户数近似最优,而且缩短了接入控制的时间。     

The estimation of probability distribution of SDE by only one sample trajectory

This paper focuses on the method of the simulation of a stochastic system and the main method of our paper is the Monte Carlo computation simulation method. Taking the stochastic Logistic equation as an example, we present the simulation of the sample trajectory by Euler scheme and the invariant probability distribution of stochastic differential equations with the Monte Carlo method. We also compare the simulation result with the analytical result for the autonomous stochastic Logistic model. Moreover, the stochastic Logistic equation with Markovian switching which is described by a Markov chain taking values in a finite state space is considered.     

A hybrid differential evolution algorithm integrated with an ant system and its application

A new hybrid differential evolution algorithm, in which an ant system is used to select the optimal base vector of mutation operation, named the ant system differential evolution (ASDE), is proposed. In ASDE, each dimension in the feasible solution space is divided into several subspaces evenly, and each subspace is marked with the same initial intensity of pheromone trails. The probability of choosing an individual as the base vector is influenced by the visibility and pheromone quantity of the individual. The trail of the selected base vector’s location subspaces will be reinforced with some pheromones, when the offspring is better than its parent. The experimental results show that the ASDE generally outperforms the other differential evolution algorithms for nine benchmark functions. Furthermore, the ASDE is applied to develop the global kinetic model for SO₂ oxidation on the Cs-Rb-V catalyst, and satisfactory results are obtained.     

Synthesis of quantum size ZnO crystals and their gas sensing properties for NO2

Quantum size ZnO crystals have been synthesized successfully by a room temperature sol-gel process. Oleic acid (OA) has been used as capping agent to control the particle size of ZnO. The crystal structure and size of the ZnO are characterized by the X-ray diffraction (XRD) and transmission electron microscope (TEM). The XRD results show the as-synthesized ZnO has hexagonal wurtzite structure and the average crystallite size is 5.7 nm which is little less than TEM result. It is testified by photoluminescence (PL) and Raman spectra that the quantum size ZnO keeps the crystal structure of the bulk ZnO and possesses more surface defects. The quantum size ZnO has the highest response of 280 to NO₂ and the highest selectivity of 31 and 49 corresponding to CO and CH₄ at operating temperature of 290 °C. The effect of calcination temperatures on sensing property and transient response of the ZnO sensor are also investigated.