Betweenness estimation in OLSR-based multi-hop networks for distributed filtering

In traditional networks special efforts are put to secure the perimeter with firewalls: particular routers that analyze and filter the traffic to separate zones with different levels of trust. In wireless multi-hop networks the perimeter is a concept extremely hard to identify, thus, it is much more effective to enforce control on the nodes that will route more traffic. But traffic filtering and traffic analysis are costly activities for the limited resources of mesh nodes, so a trade-off must be reached limiting the number of nodes that enforce them. This work shows how, using the OLSR protocol, the centrality of groups of nodes with reference to traffic can be estimated with high accuracy independently of the network topology or size. We also show how this approach greatly limits the impact of an attack to the network using a number of firewalls that is only a fraction of the available nodes.     

多点成形压力机中基本体群安装模板的有限元分析

应用ANSYS商业软件，对多点成形压力机基本体群安装模板的强度与刚度进行了分析，获得了不同厚度、不同载荷工况下的应力分布规律和变形状况，为多点成形压力机的设计提供了重要的参考依据。     

盒形件多点成形压痕现象数值模拟研究

以盒形件多点成形过程为例,从拉深形状、板厚、材质等方面进行比较,针对多点成形过程中最主要的缺陷之一—压痕现象的产生原因及其抑制方法进行了数值模拟研究,并进行了实验验证。     

2000kN板材多点成形机及其调形误差

介绍了2000kN多点成形机成形流程、参数、成形方式及特点。论述了基本体调形的理论误差,并与传统整体模具板料成形作了比较,指出多点成形是一种可实现三维板件经济、快速的柔性成形方法。     

基于STM32和小波自适应滤波算法的生理参数监测系统的研究

针对心血管疾病的高死亡率以及人口老龄化的现象,本篇文章开发了基于STM32单片机和小波自适应阈值滤波算法的可穿戴式健康监测系统。系统可分为系统微处理器、数字系统模块、人机交互模块、信号采集模块和无线通信模块等几个部分,针对人体的心率、血氧、体温等重要生理参数进行处理分析,进而对人体实时监护。系统处理器选取STM32F103C8T6作为控制芯片,显示模块选用了OLED。生理参数采集系统选用了MAX30102传感器和Pulse sense传感器分别对人体腕部和指尖心率进行采集。生理参数采集完毕后,通过进一步的A/D转化,基于提出的一种改进小波自适应阈值滤波算法降噪滤波,从而将人体的生理特征参数记录下来。再将采集的生理数据通过蓝牙传输至手机端,其中的ZigBee模块主要是把获得的数据再次输送到远程控制端内,让患者能够远程得到更好的医疗监控。本系统通过软件与硬件相结合的方式。最后通过对比论证其中心率（BPM）结果误差为±2BPM,血氧含量监测结果误差在±2%以内。     

多点测温与长线传输在分布式测温系统中的研究

针对分布式温度测量系统中多点温度测量问题,设计了长线传输电路.详细阐述了利用一个I/O端口连接多个传感器来编制公用程序的方法,以实现多个温度测量的方法,较好地解决了多个I/O口多点测温的设计问题;给出了单总线温度传感器多点测温硬件连接方法,解决了数字温度传感器在长线传输中温度的正确读取以及电路设计的关键问题.     

一种网络多点备份系统的设计和实现

该文提出并实现了一种网络多点备份系统。通过在本地应用服务器的设备驱动层之上加入写监控驱动,所有写操作将被封装成备份记录并发往本地缓存网关暂存,然后由本地缓存网关异步地将备份记录发送到多个处于不同地域的远程备份网关,最后在远程备份网关上重建写操作。该系统实现了对本地数据的多点异地备份,能够适应多种网络状况,支持Linux下所有文件系统和物理存储设备     

Model-order reduction for differential-algebraic equation systems with higher index

In this paper, a new model-order reduction (MOR) approach is presented for reducing large-scale differential-algebraic equation (DAE) systems with higher index. This approach is based upon the balanced truncation, single-point, and multi-point MOR methods. We decompose the DAE system into an ordinary differential equation (ODE) subsystem and a DAE subsystem. The DAE subsystem has the same index as the original DAE system. Then, the balanced truncation method is applied to the ODE subsystem. Both single-point and multi-point methods are used to reduce the DAE subsystem. In generally, the multi-point method can perform better than the single-point method across a wide-range of frequencies. Some numerical examples demonstrate the effectiveness of our approach.     

Assessment of forming parameters influencing spring-back in multi-point forming process: A comprehensive experimental and numerical study

Like all sheet metal forming methods, one of the main characteristics of parts formed by multi-point forming is dimensional deviation caused by elastic recovery that is known as spring-back. In this paper the effects of material property, sheet thickness and anisotropy ratio along with process parameters such as elastic layer thickness, elastic layer hardness and number of punch elements on spring-back are studied utilizing finite element simulations and experimental tests. Experimental tests are carried out under various conditions by forming V-shaped and Sin-shaped geometries. Aluminum alloy 3105, stainless steel 304 and pure copper were used as sheet materials for experiments. Likewise, black rubber with shore A hardness of 50 and polyurethane with hardness of 65 and 85 were allocated as elastic layers. The Abaqus® commercial code is employed for finite element simulations. The definition of yield behavior of utilized sheet materials is fulfilled by using three yield criteria of Barlat-89, Hill-48 and Von-Mises. Since the Barlat-89 is not adopted in Abaqus, VUMAT and UMAT user defined subroutines are provided and integrated with explicit simulation of forming process and implicit simulation of spring-back phenomenon respectively. The results indicate that parameters such as material property, blank thickness and anisotropy affect spring-back in multi-point forming. Also the thickness and hardness of elastic layers are novel ideas that should be considered in order to minimize the spring-back. In general, using the elastic layer with minimum possible thickness and greater hardness beside the maximum number of pins leads to minimum spring-back.     

面向3G的移动流媒体解决方案初探

对移动流媒体的概念和主流的Real Networks移动流媒体解决方案进行了分析,并结合3G标准和国内主要运营商的业务流程,提出了移动流媒体的可行性方案。