无线网状网技术与应用

无线网状网(WMNs)由网状路由器节点和客户机节点组成,其中的网状路由器节点组成了无线网状网的网络骨干,其移动性很小。他们一起为无线网状网和其他常规无线网络的客户机节点提供网络的无线接入。WMNs技术结合了中心式控制的蜂窝网与分布式控制的无线自组织网的优点,可有效克服这两种技术的缺陷并显著提高无线网络的性能,已经成为下一代无线通信网络的研究热点之一。WMNs可为无线个域网、局域网、校园网、城域网的一系列应用提供高速无线宽带接入服务。虽然目前WMNs技术发展很快,但其协议栈各层仍存在许多有待研究的课题。首先简要介绍了无线网状网的结构与特点;随后重点分析了其主要的几个应用领域;最后探讨了WMNs各协议层的研究现状与关键技术,并分析了该技术存在的问题及未来的研究方向。     

融合指标分组的高维混合多目标进化优化

高维混合多目标优化问题因包含多个不同类型指标,目前尚缺乏有效求解该问题的进化优化方法。提出一种基于目标分组的高维混合多目标并行进化优化方法。采用深度学习神经网络预测种群隐式性能指标;基于指标相关性,将高维混合多目标优化问题分解为若干子优化问题;采用多种群并行进化算法,求解分解后的每一子优化问题,并基于各子种群的非被占优解构建外部保存集;采用聚合函数对外部保存集个体进一步优化,得到Pareto最优解集。在室内布局优化问题中验证所提方法,实验结果表明,所提方法的Pareto最优解在收敛性、分布性以及延展性等方面均优于对比方法。     

多功能太阳能供电设备的设计与实现

根据太阳能电池以及蓄电池的充放电特性,设计并实现了一个利用太阳能电池的多功能供电设备,该供设备具有充电功能,防止过充过放,延长蓄电池的使用寿命。它可以作为无线传感节点的电源,还能将直流电逆变成市电供家用电器,并具有自动控制照明开关、显示及监控等功能。     

Preparation of aqueous soluble polyamides from renewable succinic acid and citric acid as a new approach to design bio‐inspired polymers

A novel type of aqueous soluble polyamides were prepared as renewable substitutes for ecologically benign poly(aspartic acid) by polymerization of succinic acid ester and hexamethylene diamine in the presence of citric acid ester. The copolymerization resulted in the formation of poly(amide imide) intermediates, which were hydrolyzed to aqueous solutions of polyamides. The hydrolyzed products were confirmed to be copolymers of succinamide and citramide with COOH side chains, similar to poly(aspartic acid). The polyamides showed strong chelating abilities to Ca²⁺ and Pb²⁺ metals, comparable to poly(aspartic acid). Interestingly, they also demonstrated antifreeze activities in water by reducing the ice fractions. The polyamides represent a new class of metal chelators and antifreeze protein mimics derived from succinamide and citramide. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39807.     

火箭发动机法兰连接结构的受力与变形分析

法兰连接结构在火箭发动机上得到了大量应用,但由于其结构的非线性和静不定性,给精确的应力一应变分析带来了很大的困难。文中分别在预紧和操作情况下,应用弹性理论对火箭发动机法兰连接结构进行了较为详细的载荷一变形分析。算例的计算结果表明,考虑法兰环旋转时更能反映火箭发动机法兰连接结构的真实受力情况。     

铝液静置炉炉底铝液净化系统

本文简要介绍了铝液静置炉炉底铝液净化系统的组成,通过采用炉底铝液净化系统,可有效降低炉内铝液的含氢量及杂质的含量,达到精炼的目的,并具有控制方便、自动化程度高等优点。随着技术的发展,该项技术已经得到了用户的认可。     

Rigid-flexible coupling dynamic modeling and characteristic analysis of the chain ramming mechanism

The previous studies on the dynamic characteristics of chain ramming mechanism have ignored the linkage effect of factors such as the elastic deformation of components, transmission clearance, stiffness of support body. In the model established in this paper, of which the effectiveness is verified by comparing with the experimental data, the influence of the main factors such as the elastic deformation of the chain link, the transmission clearance, the stiffness of the support body of the dynamic component and the linkage effect are all considered. The results show that the support stiffness of the sprocket shaft and the transversal support stiffness of the oil cylinder affect the longitudinal vibration of the chain. The chain link/roller clearance affects the longitudinal vibration of the chain. The track/roller clearance affects the transversal vibration of the chain at the beginning time of the ramming process and during the deceleration of the projectile.

     

高阶常系数非齐次线性微分方程特解的简捷求法

本文给出了微分方程ｙ￣（ｎ）＋ｐ＿１ｙ￣（ｎ－１）＋ｐ＿２ｙ￣（ｎ－２）＋…＋ｐ＿ｎｙ＝ｐ＿ｍ（ｘ）ｅ￣（λｘ）（其中ｐ＿１，ｐ＿２，…ｐ＿ｎ及λ为实常数，ｐ＿ｍ（ｘ）为ｍ次多项式），求特解的一种简捷方法。     

基于侧信道特征的安全代理流量分类方法

安全代理被越来越多的互联网用户用于规避网络审查和访问受限资源,因此安全代理流量的分类对于网络安全和网络管理具有重要意义.为弥补深度包检测技术在过滤和识别不良信息上的不足,提高防火墙流量探测能力,提出一种安全代理流量分类方法.提取用于安全代理流量分类的侧信道特征,包括有效载荷长度序列、信号序列等,使用机器学习和深度学习算...     

M2M energy saving strategy in 5G millimeter wave system

Telecommunication Systems - Machine to Machine technology has a broad application prospect in the 5G network, but there is a bottleneck in the energy consumption of intelligent devices powered by...