Optimal design of a three tape-spring hinge deployable space structure using an experimentally validated physics-based model

An optimal design approach is developed for a self-driven, self-locking tape-spring under a pure bending load in deployable space structures. A novel hinge with three tape springs is investigated and designed via an optimization process. Firstly, we investigate the steady-state moment and maximum stress of the hinge during deploying and folding processes using physics-based simulations. Experimental analyses are then conducted to verify the physics-based simulation results. Secondly, a parametric analysis is carried out to prove that both the tape spring thickness and subtended angle have significant effect on steady-state moment. A Response Surface Methodology (RSM) is employed to define an optimal surrogate model aimed at maximizing the steady-state moment, subjected to allowable stress. Finally, the Large Scale Generalized Reduced Gradient (LSGRG) optimization algorithm is used to solve the optimal design problem. Optimization results show that steady-state moment is increased by 19.5% while satisfying a maximum stress constraint. The proposed method is promising for designing novel deployable structures with high stability and reliability.     

使用系数矩阵变换极性转换的MPRM电路面积优化

为缩短布尔函数系统混合极性Reed-Muller(mixed-polarity Reed-Muller,MPRM)电路面积优化过程的时间,提出了能在任意极性值的MPRM间进行极性转换的系数矩阵变换方法.使用系数矩阵表示布尔函数系统,通过对系数矩阵进行分隔,使用置换和折叠操作完成MPRM极性转换以加快极性转换速度;在此基础上,给出了适用于较大规模MPRM电路的面积优化算法,其中使用遗传算法进行极性空间搜索,并采用基于最短个体距离的适应度计算方法进一步缩短优化过程中的极性转换时间.实验结果表明,与其他MPRM极性转换方法相比,文中方法能够提高MPRM电路面积优化的速度.     

基于三网合一解决方案的研究

从现有3种主要网络的现状、特点分析出发,对“三网合一”概念从全新的角度进行剖析,同时探讨了局域网三网合一的两种解决方案,这对广泛采用、建立直接交换通路的“大一统”的组网方式有重要意义。     

泄水闸预应力锚索的设计与研究

针对目前大型工程泄水闸预应力锚索设计方法和控制标准不统一的问题,本文根据《水工混凝土结构设计规范》（DL/T 5057—2009）对弧形闸门预应力混凝土闸墩的颈部提出的抗裂验算的控制标准,以某工程为例,采用工程中成熟的U型主锚索布置方式,探索泄水闸预应力锚索的设计与研究,并提出了一套以三维有限元分析为基础的设计方法和思路,对类似工程问题提供借鉴。     

基于FPGA的全局异步局部同步四相单轨握手协议实现

在常规FPGA中设计了基于LUT的异步状态保持单元,实现了全局异步局部同步系统的接口电路、时钟暂停电路,进一步完成四相单轨握手协议。基于Quartus软件的逻辑锁定技术,采用Verilog HDL进行行为描述,构建了无冒险C单元库。在Altera CycloneⅡEP2C35F672C6器件上,完成了GALS系统的时序仿真,证明了四相单轨握手的正确性。     

基于FPGA的PUSCH信道估计仿真与实现

基于最小平方(LS)算法,利用FPGA实现了一种适用于TD-LTE系统的上行信道估计算法。主要研究了如何利用FPGA实现LS算法,包括算法的介绍、方案的形成、FPGA实现的处理流程、FPGA实现结果及分析。以Virtex-5芯片为硬件平台,完成了仿真、综合、板级验证等工作。实现结果表明,该信道估计算法应用到TD-LTE系统具有良好的稳定性和可行性。     

Color texture segmentation based on image pixel classification

Image segmentation partitions an image into nonoverlapping regions, which ideally should be meaningful for a certain purpose. Thus, image segmentation plays an important role in many multimedia applications. In recent years, many image segmentation algorithms have been developed, but they are often very complex and some undesired results occur frequently. By combination of Fuzzy Support Vector Machine (FSVM) and Fuzzy C-Means (FCM), a color texture segmentation based on image pixel classification is proposed in this paper. Specifically, we first extract the pixel-level color feature and texture feature of the image via the local spatial similarity measure model and localized Fourier transform, which is used as input of FSVM model (classifier). We then train the FSVM model (classifier) by using FCM with the extracted pixel-level features. Color image segmentation can be then performed through the trained FSVM model (classifier). Compared with three other segmentation algorithms, the results show that the proposed algorithm is more effective in color image segmentation.     

Q345B钢动态再结晶动力学模型研究

在Gleeble1500热模拟机上进行Q345B钢单道次压缩变形实验,得到其真应力-真应变曲线,结合加工硬化率曲线,确定了Q345B钢动态再结晶临界应变εc、峰值应变εP和稳态应变εs。根据实验结果得到Zener-Hollomon方程和动态再结晶状态图,利用Johnson-Mehl-Avrami（JMA）方程法得到再结晶体积分数实际值,采用3种不同的再结晶体积分数预报模型对实验数据进行回归,并对再结晶体积分数实测值和预报值进行对比。结果表明,Epsilon-S／Epsilon-C模型精度最高,Epsilon-S模型精度次之,Epsilon-P模型精度最差。     

面向冗余度控制的中文多文档自动文摘

多文档自动文摘能够帮助人们自动、快速地获取信息,是目前的一个研究热点。相比于单文档自动文摘,多文档自动文摘需要更多考虑文档之间的相关性,以及文档信息之间的冗余性。因此如何控制信息冗余是多文档自动文摘的一个关键所在。该文在考虑文摘特性的基础上提出了一个冗余度控制模型,该模型通过计算文本单元在主题概率分布之间的相似度来决定句子的选择,从而达到控制冗余的目的。实验结果表明,该方法能够有效降低冗余度,且总体性能优于现有的自动文摘系统。