面向5G网络的MEC部署方案

多接入边缘计算技术通过将计算存储能力与业务服务能力向网络边缘迁移,使应用、服务和内容可以实现本地化、近距离、分布式部署,从而在一定程度上解决了5G增强移动宽带、低时延高可靠以及大规模机器通信类终端连接等场景的业务需求.本文在分析MEC技术在LTE网络中的应用方案以及对于5G网络的价值与意义的基础上,给出了5G MEC部...     

从硬件角度优化GSM系统低话务小区的几种方法

本文通过对GSM系统低话务小区产生原因的分析,提出从硬件角度优化此类小区的几种方法.主要有覆盖调增、硬件排障、载波池技术使用等.     

激光测速系统中驱动电路的研究

激光测速技术的主要方法有脉冲法和相位法。由于激光相位法测速系统设计复杂,成本较高,因此只考虑脉冲法激光测速。针对脉冲法激光测速,提出了两种易于实现的脉冲驱动电路的设计方法,方法一基于555振荡电路和CPLD,主要利用了CPLD的逻辑延时;方法二完全基于CPLD的逻辑实现。逻辑分析和仿真结果证明,两种方法都可以驱动激光器工作,产生的驱动脉冲的频率和脉宽均可调节。     

MSComm串行端口通信技术应用分析

阐述了串行端口通信技术的发展,介绍了MSComm控件的部分属性,用流程图方式对MSComm控件的使用流程进行了详细说明,分析了MSComm控件在工程实例中的应用,论述了自动化数据采集、处理系统的工作原理,对系统的软硬件进行了设计,能够满足系统实时性、稳定性的需求.     

WDM疏导网络中一种新的多播业务路由算法

研究了波分复用(WDM)网状网中动态多播业务量疏导,提出一种新的辅助疏导模型,其可以描述当前网络资源状况和节点分光特点,并动态更新.进而提出一种有效的多播业务量疏导启发式算法(MGA),将业务的多播选路和波长分配同时完成.仿真表明,该算法在波长连续性限制、网络波长和节点收发器数目有限的情况下,具有较低网络阻塞率.     

Review and perspective on encrypted traffic identification research

Considering the importance of encrypted traffic identification technology and existing research work,first,the type of encrypted traffic identification according to the demand of traffic analysis were introduced,such as protocols,applications and services.Second,the encrypted traffic identification technology was summarized,and identification technology was compared from multiple views.Third,the deficiencies and the affecting factors of the existing encrypted traffic identification technologies were induced,such as tunneling,traffic camouflage technology,new protocols of HTTP/2.0 and QUIC.Finally,prospect trends and directions of future research on encrypted traffic identification were discussed.     

A well‐balanced upstream flux‐splitting finite‐volume scheme for shallow‐water flow simulations with irregular bed topography

This study extends the upstream flux‐splitting finite‐volume (UFF) scheme to shallow water equations with source terms. Coupling the hydrostatic reconstruction method (HRM) with the UFF scheme achieves a resultant numerical scheme that adequately balances flux gradients and source terms. The proposed scheme is validated in three benchmark problems and applied to flood flows in the natural/irregular river with bridge pier obstructions. The results of the simulations are in satisfactory agreement with the available analytical solutions, experimental data and field measurements. Comparisons of the present results with those obtained by the surface gradient method (SGM) demonstrate the superior stability and higher accuracy of the HRM. The stability test results also show that the HRM requires less CPU time (up to 60%) than the SGM. The proposed well‐balanced UFF scheme is accurate, stable and efficient to solve flow problems involving irregular bed topography. Copyright © 2009 John Wiley & Sons, Ltd.     

全球网络中立进展及对OTT的影响

随着互联网的普及，特别是移动互联网的日益广泛，网络中立问题仍然是热点问题，从美国逐步扩展到全球其他地区，如亚洲、欧洲和南美洲等。目前网络中立问题主要聚焦在对运营商网络管理策略合法性的争论之上，特别是对OTT服务的管理问题。由于OTT应用不断涌现，给电信运营商网络带来很大压力，多国运营商采取措施应对OTT。     

IP网流量工程的一种权值设置方法

提出一种新的基于传统路由协议的流量控制方法。该方法首先在不限制总流量条件下求解最小化最大连接利用率。然后在固定最大连接利用率条件下最小化总流量。由此求得最优流量分配方案并从其对偶问题中求出各连接的权值配置。实验结果显示，文中算法较现有算法明显降低最大连接利用率，并且增加了稳定性。     

Optimization of listening time of S-MAC for wireless sensor networks

In wireless sensor networks, sensor nodes are usually battery-operated computing and sensing devices, hence operations are limited by the initially equipped batteries, which are hard to be recharged or replaced. In this sense, saving energy consumption becomes significant. As most energy waste is from the always-on wireless interface, S-MAC is suggested to reduce energy consumption by introducing periodic listen/sleep scheme. However, when designing the listening time, S-MAC fails to consider the traffic distribution factor. In this article, an optimization for this scheme is proposed based on the distribution model. Evaluations show that the optimized S-MAC achieves considerable improvement in energy and latency.