ZigBee网络移动节点接入与切换机制仿真分析

ZigBee技术是一种基于IEEE802．15．4的物理层和媒体访问层标准,与其他短距离无线协议相比,是有低功耗、高可靠性、低复杂度和支持大量网络节点等显著优点的无线通信协议。在工业、家居、军事等很多领域有着广阔的前景。本文首先对网络移动节点的接入和切换机制进行了介绍,然后对网络移动节点的接入和切换机制进行仿真和分析,最后提出了对网络移动节点的接入和切换机制的改进。     

一种在铸件缺陷识别中的区域分形分割方法

在利用X射线对铸造缺陷识别的过程中,由于X光图像中铸件形成的背景复杂,传统的区域分割技术难以分割出缺陷集中的兴趣区域。利用缺陷边缘的分形特性从铸件边缘线图中确定缺陷的边缘线,以聚类方法将缺陷边缘线聚集的区域,即缺陷集中的兴趣区域分割出来。针对汽车铝合金轮毂铸件X光图像,用铸造缺陷区域的分割实验结果证明了该方法的有效性。     

基于最优形态学滤波的面料缝纫加工检测

为了对服装加工质量进行自动检测,提出了一种对针织面料缝纫加工的疵点进行自动检验的方法。该方法首先基于遗传算法进行结构元素的寻优,然后通过图像的数学形态学滤波处理来消除面料组织的正常纹理对图像分割的干扰;最后利用灰度阈值实现图像分割来得到表现缝线和加工疵点特征的二值图像。实验结果表明,该方法是有效的。     

基于改进EOH特征的行人检测

行人检测是物体检测领域的一大难点。为了进一步提高行人检测的精度和速度,将Kobi Levi和Yair Weiss提出的边缘方向直方图特征和传统的Adaboost算法两者有机地结合起来,提出了一种基于改进的EOH特征的行人检测算法。该算法首先对原先只适用于较为简单的人脸检测的EOH(edge orientation histogram)特征进行了改进,弥补了其对于行人的对称性特征的描述能力不足的问题,然后通过改进Adaboost算法中对样本权值进行调整的策略来减少overfitting。实验证明,该方法的检测性能能够接近目前行人检测的领先水平。在误报率为1/10000时,该算法在一个复杂的Inria行人数据集上的检测率可以达到90%。对于640×480大小的图片,该算法的检测速度可以达到2fps。     

新舟60模拟机飞行指引系统实现

以新舟60飞机为模型,C 语言为开发工具,开发出一套完整可行的飞行指引(F/D)软件.用以替代Collins APS-85飞控计算机完成飞行指引功能,并成功地在飞行模拟机上通过测试且得到应用.具有成本低廉,稳定可靠的特点,能够满足飞行员训练的需要.     

Computer aided measurement of the electromagnetic parameter for the microwave absorbing materials

The electromagnetic parameters of microwave absorbing materials are important criteria when appraising the properties of absorbents. For reconstruction of parameters which belongs to the inverse scattering problem, the test data in requirement of traditional impedance method are "just enough" and not "redundant" to comprehensively evaluate the electromagnetic properties of materials. A novel optimization approach involving multiple impedance measurements is introduced in this paper to implement automatic measurement for electromagnetic parameters on microwave slot-line. Some results for standard samples and microwave absorbing materials are given.     

Iteration algorithm for computer-aided speckle interferometry

An iteration algorithm for the analysis of speckle interference patterns is presented. First, four digitized phase-shifted patterns are locally averaged. The phase information is then extracted by the usual phase shift algorithm. The wrapped phase is in turn used to reconstruct four new phase-shifted patterns. These three steps form a cycle. Repetition of the three steps has a great effect on suppressing speckle noise. Theoretical study shows that the iterated phase converges to a perfect result under ideal conditions. In general, the iteration causes little error but improves the phase information a great deal. The signal-to-noise ratio rises when additional iterations are performed.     

A quantitative solution to Constraint Satisfaction Problem (CSP)

Constraint Satisfaction Problem (CSP) is an important problem in artificial intelligence and operations research. Many practical problems can be formulated as CSP, i.e., finding a consistent value assignment to variables subject to a set of constraints. In this paper, we give a quantitative approach to solve the CSPs which deals uniformly with binary constraints as well as high order,k-ary (k ≥ 2) constraints. In this quantitative approach, using variable transformation and constraint transformation, a CSP is transformed into a satisfiability (SAT) problem. The SAT problem is then solved within a continuous search space. We will evaluate the performance of this method based on randomly generated SAT problem instances and regularly generatedk-ary (k ≥ 2) CSP problem instances.     

Diffractive-phase-element design that implements several optical functions

A scheme for the design of diffractive phase elements (DPE's) that integrates several optical functions is presented in a consistent sense based on the general theory of amplitude-phase retrieval and the Yang-Gu algorithm [Appl. Opt. 33, 209 (1994)]. We extend the original Yang-Gu algorithm to treat a system illuminated by a beam of incident light whose components are at different wavelengths, and a set of equations for determining the phase distribution of the DPE is derived. The profile of a surface-relief DPE can be designed with an iterative algorithm. Numerical simulations are carried out for the design of one-dimensional DPE's capable of both demultiplexing different wavelength components and focusing each partial wave at predetermined positions. The influence of the extension of sampling points in the DPE's from ideal geometric points to physical spots on design results is also investigated. The numerical simulation results show that the new algorithm can be used successfully to design the desired DPE's. It is therefore expected to be useful in the design of DPE's for micro-optical systems.