New algorithm for variable-rate linear broadcast network coding

To adjust the variance of source rate in linear broadcast networks,global encoding kernels should have corresponding dimensions to instruct the decoding process.The algorithm of constructing such global encoding kernels is to adjust heterogeneous network to possible link failures.Linear algebra,graph theory and group theory are applied to construct one series of global encoding kernels which are applicable to all source rates.The effectiveness and existence of such global encoding kernels are proved.Based on information flow,the algorithm of construction is explicitly given within polynomial time(|E·|T|ω2max) and the memory complexity of algorithm is O(|E|).Both time and memory complexity of this algorithm proposed can be O(ωmax) less than those of algorithms in related works.

Network Coding-based Reliable Broadcast Transmission in Wireless Networks

Recently, network coding has been applied to the loss recovery of reliable broadcast transmission in wireless networks. Since it was proved that fi nding the optimal set of lost packets for XOR-ing is a complex NP-complete problem, the available time-based retransmission scheme and its enhanced retransmission scheme have exponential computational complexity and thus are not scalable to large networks. In this paper, we present an efficient heuristic scheme based on hypergraph coloring and also its enhanced heuristic scheme to improve the transmission efficiency. Basically, our proposed schemes fi rst create a hypergraph according to the packet-loss matrix. Then our schemes solve the problem of generating XORed packets by coloring the edges of hypergraph. Extensive simulation results demonstrate that, the heuristic scheme based on hypergraph coloring and its enhanced scheme can achieve almost the same transmission efficiency as the available ones, but have much lower computational complexity, which is very important for the wireless devices without high computation capacity.

New mixed broadcast scheduling approach using neural networks and graph coloring in wireless sensor network

Due to the mutual interference and sharing of wireless links in TDMA wireless sensor networks, conflicts will occur when data messages are transmitting between nodes. The broadcast scheduling problem （BSP） is aimed to schedule each node in different slot of fixed length frame at least once, and the objective of BSP is to seek for the optimal feasible solution, which has the shortest length of frame slots, as well as the maximum node transmission. A two-stage mixed algorithm based on a fuzzy Hopfield neural network is proposed to solve this BSP in wireless sensor network. In the first stage, a modified sequential vertex coloring algorithm is adopted to obtain a minimal TDMA frame length. In the second stage, the fuzzy Hopfleld network is utilized to maximize the channel utilization ratio. Experimental results, obtained from the running on three benchmark graphs, show that the algorithm can achieve better performance with shorter frame length and higher channel utilizing ratio than other exiting BSP solutions.

Impact of small-world topologies on broadcasting for wireless sensor networks

Broadcasting is an important operation and been widely used in wireless sensor networks （WSNs）. These networks are power constrained as nodes operate with limited battery power. Wireless sensor networks are spatial graphs that have much more clustered and much high path-length characteristics. After considering energy- efficient broadcasting in such networks, by combining the small-world characteristic of WSNs and the properties of ant algorithm to quickly identify an optimal path, small-world power-aware broadcast algorithm is introduced and evaluated. Given different densities of network, simulation results show that our algorithm significantly improves life of networks and also reduces communication distances and power consumption.

A NEW METHOD FOR CONSTRUCTING MINIMAL BROADCAST NETWORKS

Ⅰ. INTRODUCTION Broadcast is the process of message dissemination in a communication network whereby a message, originated by a node (originator), is transmitted to all the other nodes of the network. This concept finds wide applications in the control of distributed systems. Broadcast considered in this note possesses the following constraints:

Scheduling for Uncertain Data Broadcast in Mobile Networks

With the increasing popularity of wireless sensor network and GPS （ global positioning system）, uncertain data as a new type of data brings a new challenge for the traditional data processing methods. Data broadcast is an effective means for data dissemination in mobile networks. In this paper, the def＇mition of the mean uncertainty ratio of data is presented and a broadcasting scheme is proposed for uncertain data dissemination. Simulation results show that the scheme can reduce the uncertainty of the broadcasted uncertain data effectively at the cost of a minor increase in data access time, in the case of no transmission error and presence of transmission errors. As a result, lower uncertainty of data benefits the qualifies of the query results based on the data.

BROADCAST SCHEDULING WITH MIMO LINKS IN MULTI-HOP AD HOC NETWORKS

As the current medium access control protocols with Multiple Input Multiple Output (MIMO) links only bear point to point service, broadcast scheduling algorithm in ad hoc networks with MIMO links is proposed. The key to the proposed broadcast scheduling algorithm is the time slot scheduling algorithm which guarantees collision-free transmissions for every node and the mini- mum frame length. The proposed algorithm increases the simultaneous transmissions of MIMO links efficiently. Due to the interference null capacity of MIMO links, the interference node set of each node can decrease from two-hop neighbors to one-hop neighbors possibly. Simulation results show that our algorithm can greatly improve network capacity and decrease average packet delay.

Broadcasting with Controlled Redundancy and Improved Localization in Wireless Sensor Networks

Wireless sensor networks （WSNs） consist of sensor nodes that broadcast a message within a network. Efficient broadcasting is a key requirement in sensor networks and has been a focal point of research over the last few years. There are many challenging tasks in the network, including redundancy control and sensor node localization that mainly depend on broadcasting. In this paper, we propose a broadcasting algorithm to control redundancy and improve localization （BACRIL） in WSNs. The proposed algorithm incorporates the benefits of the gossip protocol for optimizing message broadcasting within the network. Simulation results show a controlled level of redundancy, which is up to 57.6% if the number of sensor nodes deployed in a 500 m×500 m area are increased from 50 to 500.

A Preamble-Based Broadcasting Technique for Wireless Ad Hoc Sensor Networks

Broadcasting is a fundamental operation in any wireless networks, more so in wireless ad hoc sensor networks, where each sensor node has limited transmission range as well as battery power. Although broadcasting in wireless ad hoc sensor networks has many advantages but it can cause serious problems like-broadcast storm, which could cause a lot of contention, redundant retransmission, collision and most importantly, drain immense amount of energy from limited battery powered sensor nodes. In this work, our objective is to reduce the number of retransmission and energy consumption of sensor nodes by using the duty cycle property of wireless ad hoc sensor networks. We propose a preamble-based broadcasting technique for wireless ad hoc sensor networks. We show that in dense wireless ad hoc sensor networks a small size preamble can give maximum network-wide data dissemination rather than using the large preamble, which will only consume immense amount of energy during packet reception.

Quantum Secret Broadcast for Wireless Quantum Networks

In wireless quantum networks, nodes communicate by means of pre-distribution for entangled pairs and relay path establishment for quantum teleportation. However, simple point-to-point communication seriously restricts the efficiency of quantum communication. Inspired by sharing idea of quantum secret sharing (QSS), which is based on three collaborative nodes with pre-shared GHZ (Greenberger-Horne-Zeilinger) states, we propose a quantum secret broadcast scheme to improve network performance. In a cluster net-work cored on three parties of QSS, three cluster heads with pre-shared GHZ states are senders, while cluster members are receivers. One cluster head encodes secret messages on auxiliary particles by performing certain operations on them with GHZ particles, then three cluster heads measure their own par-ticles and broadcast measurement results honestly. Based on the specific correlation of measurement results and secret messages, all receivers can re-cover the secret messages. Furthermore, to prevent eavesdropping, cluster heads can update an encoding key periodically. Analysis shows the proposed scheme is more efficient than previous schemes in wireless quantum net-works, especially when the number of receivers is larger. Besides, in the proposed scheme, attacks on quantum channel based on GHZ state can be detected, and eavesdroppers cannot recover messages correctly for lack of suitable decoding key.

Forwarding vs. Network Coding: Efficient Broadcasting in Multihop Wireless Networks

Broadcasting is used as a building block in many MANET (Mobile Ad hoc Network) routing protocols. In addition, broadcasting is a key primitive in ad hoc networks to support group-based applications. Efficiently supporting broadcasting in multihop wireless networks is therefore important. In this paper, we compare ef-ficient broadcasting protocols based on packet forwarding with those based on network coding. Using a number of network scenarios, we derive lower bounds for the required number of packet retransmissions at the MAC layer to support broadcast with and without applying network coding techniques. We compare these lower bounds with each other, as well as with protocols proposed for each approach. More specifically, we use SMF and PDP as sample forwarding-based broadcast protocols, and a simple XOR-based coding protocol over SMF and PDP as representative network coding solution. The results show that neither packet forwarding protocols nor network coding protocols achieve the theoretical lower bounds, in particular as the size of the network area (at constant density) increases. The comparison of the lower bounds also shows that network coding does have a potential performance advantage over packet forwarding solutions for broad-casting in multi-hop wireless networks, in particular for larger fixed density networks, justifying its inherent increased complexity.

Joint Power Control and Scheduling for Two-Cell Energy Efficient Broadcasting with Network Coding

We consider the energy minimization problem for a two-cell broadcasting system, where the focus is devising energy efficient joint power control and scheduling algorithms. To improve the retransmission efficiency, linear network coding is applied to broadcast packets. Combined with network coding, an optimal algorithm is proposed, which is based on dynamic programming. To reduce computational complexity, two sub-optimal algorithms are also proposed for large networks. Simulation results show that the proposed schemes can reduce energy consumption up to 57% compared with the traditional Automatic Repeat-reQuest (ARQ).

Network coding-aware cache replacement policy in on-demand 0broadcast environments

Network coding has been proved to be an effective technique in improving the performance of data broadcast systems because clients requesting different data items can be served simultaneously in one broadcast. Previous studies showed that its efficiency is highly related to the content of clients' cache. However, existing data broadcast systems do not take network coding information into account when making cache replacement decisions. In this paper, we propose two networks coding-aware cache replacement policies called DLRU and DLRU-CP to supplement network coding assisted data broadcast in on-demand broadcast environments. In DLRU, both data access and decoding contribution are taken into account to make replacement decisions. DLRU-CP is based on DLRU but allows clients to retrieve decodable data items that have not been requested yet. The performance gain of our proposed cache replacement policies over traditional cache replacement policy is shown in the simulation results, which demonstrate conclusively that the proposed policies can effectively reduce the overall response time.

校园网二层环路防治技术研究

作为校园网常见问题,二层环路故障不仅隐蔽性强,而且定位也较为困难。文章分析了二层环路网络故障所带来的危害,给出了具体检测方法和防范措施。研究对于优化校园网运维管理体系,进一步提高校园网的可靠性和稳定性具有一定实践意义。

基于深度学习的乘务英语自动播报检测系统设计

乘务英语能够引导国外游客做出正确的选择,因此,为了使乘务英语自动播报中的表达更为准确和清晰,提出了一种基于深度学习的乘务英语播报语法纠错检测系统。在系统中利用深度置信网络来构建乘务英语播报语法纠错模型,并在此模型基础上进行乘务英语自动播报语法检测和纠正系统。在模型和系统的测试中显示,基于深度置信网络的语法纠错模型帧损失率仅为0.11%,乘务英语播报检测系统也能够在运行中不断进行更新,确保语音数据的实效性。以上结果表明,深度置信网络能够对乘务英语进行语法纠错,并通过反馈提升乘务英语播报的准确性,对我国商用英语的应用和发展具有重要意义。

无线发射台站智慧运维支撑管理系统审计日志模块的设计与实现

阐述应用于广播电视无线发射台站智慧运维支撑管理系统审计日志模块的总体设计思路和实现要点。该模块通过对系统操作和事件进行全面收集、存储、分析和告警通知,旨在提高广播电视的安全播出和网络安全水平。

5G时代网络直播赋能高校党员教育培训创新研究

网络直播在高校党员教育培训中的应用蓬勃发展,并且随着5G技术的驱动迎来了新的发展契机,具有实现资源共享、强化群体认同、打造沉浸体验、为受众精准画像等功能价值。尽管5G网络直播赋能高校党员教育培训全新的场景形态和实践样貌,但仍然存在软硬件基础条件尚不成熟、技术附魅弱化人文关怀、复合型人才缺位等诸多挑战。推动5G网络直播与党员教育培训融合发展,落实立德树人根本任务,需要构建共建共治共享新格局,砥砺初心坚持“内容为王”,加强人才引育管用汇聚发展动能。

面向信息年龄的车辆状态更新网络采样与功率控制

针对基于广播通信的车辆状态更新网络,采用最小时间戳优先的D/Geo/1/1排队系统模型传输数据包,利用排队论分析了接收端的信息年龄(AoI,age-of-information)中断概率和发送端的平均发送功率,根据AoI中断概率随数据包采样速率和发送功率变化的单调性,提出了基于迭代的采样速率和发送功率联合优化算法,通过采样与功率控制在功率受限的条件下最小化所有接收端中的最大AoI中断概率,实现了接收端信息新鲜度的公平提升。仿真结果验证了理论分析的准确性和算法的高效性。

基于“声”态环境下的网络音频平台播音创作优化方法研究

随着互联网的不断发展和相关技术水平的提升,目前人们接收信息的方式和习惯发生了重大改变。以移动设备和网络的发展为例,快捷的网络服务和高质量设备的使用导致人们的收听状态呈现移动化、碎片化特征,而网络音频平台作为播音节目的主要载体,在内容的生产创作上需要进一步满足时代发展和人们收听的需求。本文从“声”态环境出发,针对网络音频平台播音创作的发展需求,提出了具体的优化策略,为“声”态环境下的播音工作者提供新的创作思路,促进行业的未来发展。