A Tree-Based Data Collecting Network Structure for Wireless Sensor Networks

In a sensor network with a large number of densely populated sensor nodes, a single target of interest may be detected by multiple sensor nodes simultaneously. Data collected from the sensor nodes are usually highly correlated, and hence energy saving using in-network data fusion becomes possible. A traditional data fusion scheme starts with dividing the network into clusters, followed by electing a sensor node as cluster head in each cluster. A cluster head is responsible for collecting data from all its cluster members, performing data fusion on these data and transmitting the fused data to the base station. Assuming that a sensor node is only capable of handling a single node-to-node transmission at a time and each transmission takes T time-slots, a cluster head with n cluster members will take at least nT time-slots to collect data from all its cluster members. In this paper, a tree-based network structure and its formation algorithms are proposed. Simulation results show that the proposed network structure can greatly reduce the delay in data collection.     

无线传感网络中的动态集群密钥管理方案

Wireless sensor networks are open architectures, so any potential threat can easily intercept, wiretap and counterfeit the information. Therefore, the safety of WSN is very important. Since any single key system cannot guarantee the security of the wireless sensor network for communications, this paper introduces a hierarchical key management scheme based on the different abilities of different sensor nodes in the clustered wireless sensor network. In this scheme, the nodes are distributed into several clusters, and a cluster head must be elected for each cluster. Private communication between cluster heads is realized through the encryption system based on the identity of each head while private communication between cluster nodes in a same cluster head is achieved through the random key preliminary distribution system. Considering the characteristics of WSN, we adopt dynamic means called dynamic cluster key management scheme to deal with master key, so master key will be updated according to the changed dynamic network topology. For cluster head node plays a pivotal role in this scheme, a trust manage-ment system should be introduced into the election of the cluster head which will exclude the malicious node from outside the cluster, thus improve the whole network security.     

A Cooperative Security Monitoring Mechanism Aided by Optimal Multiple Slave Cluster Heads for UASNs

As each cluster head(CH) sensor node is used to aggregate, fuse, and forward data from different sensor nodes in an underwater acoustic sensor network(UASN), guaranteeing the data security in a CH is very critical. In this paper, a cooperative security monitoring mechanism aided by multiple slave cluster heads(SCHs) is proposed to keep track of the data security of a CH. By designing a low complexity "equilateral triangle algorithm(ETA)", the optimal SCHs(named as ETA-based multiple SCHs) are se...     

面向精准农业的无线多媒体传感网设计(英文)

To satisfy the needs of modern precision agriculture, a Precision Agriculture Sensing System (PASS) is designed, which is based on wireless multimedia sensor network. Both hardware and software of PASS are tailored for sensing in wide farmland without human supervision. A dedicated single-chip sensor node platform is designed specially for wireless multi-media sensor network. To guarantee the bulky data transmission, a bitmap index reliable data transmission mechanism is proposed. And a battery-array switching system is design to power the sensor node to elongate the lifetime. The effectiveness and performance of PASS have been evaluated through comprehensive experiments and large-scale real-life deployment.     

Near optimal cluster-head selection for wireless sensor networks

Clustering in wireless sensor networks is an effective way to save energy and reuse band- width. To our best knowledge, most of the clustering protocols proposed in literature are of a dynamic type, where cluster heads are selected in each period, followed by cluster formation. In this paper, a new static type clustering method called Hausdorff clustering, which is based on the location of sensor nodes as well as communication efficiency and network connectivity, is proposed. The cluster head, however, is rotated within the cluster by a fuzzy logic algorithm that optimizes the network lifetime. Simulation results show that this approach can significantly increase the lifetime of the sensor network.     

Energy efficient fault-tolerant multipath routing scheme for wireless sensor networks

In wireless sensor network （MSN）, reliability is the main issue to design any routing technique. To design a comprehensive reliable wireless sensor network, it is essential to consider node failure and energy constrain as inevitable phenomena. In this paper we present energy efficient node fault diagnosis and recovery for wireless sensor networks referred as energy efficient fault tolerant multipath routing scheme for wireless sensor network. The scheme is based on multipath data routing. One shortest path is used for main data routing in our scheme and other two backup paths are used as alternative path for faulty network and to handle the overloaded traffic on main channel. Shortest pat data routing ensures energy efficient data routing. Extensive simulation results have revealed that the performance of the proposed scheme is energy efficient and can tolerates more than 60% of fault.     

An Improved Underwater Acoustic Network Localization Algorithm

Underwater sensor network can achieve the unmanned environmental monitoring and military monitoring missions.Underwater acoustic sensor node cannot rely on the GPS to position itself,and the traditional indirect positioning methods used in Ad Hoc networks are not fully applicable to the localization of underwater acoustic sensor networks.In this paper,we introduce an improved underwater acoustic network localization algorithm.The algorithm processes the raw data before localization calculation to enhance the tolerance of random noise.We reduce the redundancy of the calculation results by using a more accurate basic algorithm and an adjusted calculation strategy.The improved algorithm is more suitable for the underwater acoustic sensor network positioning.     

Top-K Query Framework in Wireless Sensor Networks for Smart Grid

The smart grid has caught great attentions in recent years, which is poised to transform a centralized, producer-controlled network to a decentralized, consumer- interactive network that＇s supported by fine-grained monitoring. Large-scale WSNs （Wireless Sensor Networks） have been considered one of the very promising technologies to support the implementation of smart grid. WSNs are applied in almost every aspect of smart grid, including power generation, power transmission, power distribution, power utilization and power dispatch, and the data query processing of ＇WSNs in power grid＇ become an hotspot issue due to the amount of data of power grid is very large and the requirement of response time is very high. To meet the demands, top-k query processing is a good choice, which performs the cooperative query by aggregating the database objects＇ degree of match for each different query predicate and returning the best k matching objects. In this paper, a framework that can effectively apply top-k query to wireless sensor network in smart grid is proposed, which is based on the cluster-topology sensor network. In the new method, local indices are used to optimize the necessary query routing and process intermediate results inside the cluster to cut down the data traffic, and the hierarchical join query is executed based on the local results.Besides, top-k query results are verified by the clean-up process, and two schemes are taken to deal with the problem of node＇s dynamicity, which further reduce communication cost. Case studies and experimental results show that our algorithm has outperformed the current existing one with higher quality results and better efficiently.     

P-Zone： Connectivity-based Packet Path Tracing in Wireless Sensor Networks

In large-scale Wireless sensor networks （WSNs）, the network status is complex and unpredictable, which brings great challenges to practical network design and management. Tracing the route path of each data packet in the network is an important way to observe network behaviors and understand network dynamics. However, tracing the full route path of each packet could be highly challenging, due to the hard resource con- straint in WSNs. Our previous work proposes a hash-based path tracing mechanism, and leverages network connectivity and node locations to reduce the computational complexity. However, the node locations may be unavailable in some scenarios. In this work, we further propose a location-free enhancement to the hash-based path tracing mechanism, called P-Zone. P-Zone requires only network connectivity information to reduce the computational complexity. Theoretical analysis and practical simulations are conducted to evaluate the effectiveness and performance of our design. The results indicate that P-Zone can significantly reduce the computational complexity of the hashbased path tracing mechanism, while effectively tracing the full route path of each packet in the network in a real-time manner, and outperforms the state-of-the-art methods.     

Systematic energy-balanced cooperative transmission scheme in wireless sensor networks

Energy efficiency is a critical issue in wireless sensor networks(WSNs).In order to minimize energy consumption and balance energy dissipation throughout the whole network,a systematic energy-balanced cooperative transmission scheme in WSNs is proposed in this paper.This scheme studies energy efficiency in systematic view.For three main steps,namely nodes clustering,data aggregation and cooperative transmission,corresponding measures are put forward to save energy.These measures are well designed and tightly coupled to achieve optimal performance.A half-controlled dynamic clustering method is proposed to avoid concentrated distribution of cluster heads caused by selecting cluster heads randomly and to get high spatial correlation between cluster nodes.Based on clusters built,data aggregation,with the adoption of dynamic data compression,is performed by cluster heads to get better use of data correlation.Cooperative multiple input multiple output(CMIMO) with an energy-balanced cooperative cluster heads selection method is proposed to transmit data to sink node.System model of this scheme is also given in this paper.And simulation results show that,compared with other traditional schemes,the proposed scheme can efficiently distribute the energy dissipation evenly throughout the network and achieve higher energy efficiency,which leads to longer network lifetime span.By adopting orthogonal space time block code(STBC),the optimal number of the cooperative transmission nodes varying with the percentage of cluster heads is also concluded,which can help to improve energy efficiency by choosing the optimal number of cooperative nodes and making the most use of CMIMO.     

基于数据库的IP网络管理研究

针对广泛应用的网络管理协议SNMP,研究了如何高效地进行基于SNMP的IP网络管理。首先分析了目前基于SNMP的IP网络管理框架结构中存在的一些问题,然后有针对性地提出了基于数据库的SNMP网络管理结构,并具体分析了改进结构的工作机制。     

基于SNMP的EPON网管系统的设计与实现

以太无源光网络(EPON)即将成为宽带接入的最有效的通信方法,为EPON系统提供一个稳定、有效的网络管理系统显得尤为重要。简单网络管理协议(SNMP)是当今应用最广泛的网络管理协议。本文分析了基于SNMP的EPON网管结构,按配置管理、性能管理、故障管理、安全管理等功能设计了EPON网管系统,并分别在管理站和代理站上予以实现。     

基于移动代理的网络管理系统研究

大多数网络管理系统都是通过基于一种管理者／代理者（Manager／Agent）模型的简单网络管理协议（SNMP）实现，它具有一定的局限性，并且在管理上缺乏足够的灵活性和智能性。移动代理具有移动性和智能性等特点，通过将其与网络管理技术相结合，能够大大提高网络管理系统的灵活性和可扩展性，使整个网络管理系统的性能得到很好的改善。     

SNMP二级代理机制的研究与实现

首先描述了SNMP协议及其网络管理机制，然后对SNMP二级代理机制进行了探讨，并给出了具体的实现过程。     

基于SNMP和AgentX的SDH网络管理

网络管理是同步数字体系(SDH)网络的重要组成部分。考虑到简单网络管理协议 (SNMP)自身拥有的简单实用特性,以及AgentX协议为网络设备带来了灵活的可扩展性,本文提出了一个基于SNMP和AgentX的SDH网络管理方案。文中详细论述了该管理方案,划分、说明了实现过程中几个关键的设计模块。该方案的实施,使得SDH的网络管理更加灵活且高效。     

SNMPv3网络安全管理研究

提出计算机网络管理面临的安全威胁，分析了简单网络管协议SNMPv3及其基于用户的安全模型USM的安全机制，最后总结SNMPv3有待考虑的问题并总体评价了SNMPv3的安全性。     

一种安全网络管理协议的设计与实现

文章以SNMP简单网络管理协议为参照对象,针对SNMP协议现有的一些安全隐患及管理效率的不足,从安全性增强和新型管理库(TLV)设计的角度介绍了一种增强型安全网络管理协议的设计思路及实现方案,并且通过介绍该协议在工程中的应用情况,体现了使用该协议可增加网络传输安全性、可扩展性强和可提高管理效率等优势。     

在VC++6.O平台下基于SNMP网络管理软件的开发

SNMP（简单网络管理协议）是目前TCP/IP网络中应用最为广泛的网络管理协议.本文详细介绍了SNMP的基本原理和框架结构,并给出了一个在VC＋＋6.0平台下利用SNMP＋＋进行快速网络管理应用程序开发的简单例子.     

Ad Hoc网络中SNMP代理的研究和实现

研究了在基于TCP／IP体制的Ad Hoc网络中,利用简单网络管理协议SNMP和网管代理解决严重和复杂的网络管理问题。在分析SNMP协议工作原理的基础上,探讨了SNMP代理的工作流程、组成模块和实现方式,并搭建Ad Hoc网络实验环境进行了测试验证。实验结果表明,通过SNMP协议和代理,能够有效管理和控制Ad Hoc网络中的关键参数,降低了系统的复杂程度和技术风险。     

基于Browser/Server模式的网络管理模型

研究基于ＴＣＰ／ＩＰ的简单网络管理协议（ＳＮＭＰ）及管理信息库（ＭＩＢ）的信息特点,提出一种基于Ｂｒｏｗｓｅｒ／Ｓｅｒｖｅｒ模式的网络管理模型,该模型将数据库数据分成动态数据和准静态数据,采用浏览器／Ｄａｔａｂａｓｅ服务器二元模式表现形式,提高了网络的信息处理速度,具有一定的理论意义和实用价值。