“Half of the Node Records Are Forged?”: The Problemof Node Records Forgery in Ethereum Network

Ethereum, currently the most widely utilized smart contracts platform, anchors the security of myriad smartcontracts upon its own robustness. Its foundational peer-to-peer network facilitates a dependable node connectionmechanism, whereas an efficient data-sharing protocol constitutes as the bedrock of Blockchain network security.In this paper, we propose NodeHunter, an Ethereum network detector implemented through the application ofsimulation technology, which is capable of aggregating all node records within the network and the interconnectednessbetween them. Utilizing this connection information, NodeHunter can procure more comprehensive insightsfor network status analysis compared to preceding detection methodologies. Throughout a three-month period ofunbroken surveillance of the Ethereum network, we obtained an excess of two million node records along with overone hundred million node acquaintances. Analysis of the gathered data revealed that an alarming 49% or more ofthese node records were maliciously forged.

一种基于空洞节点检测的可靠无人机自组网路由协议

针对高动态无人机自组网中节点之间链路生存时间(Link Live Time,LLT)短和节点遭遇路由空洞次数多的问题,提出了一种基于空洞节点检测的可靠无人机自组网路由协议——GPSR-HND(Greedy Perimeter Stateless Routing Based on Hollow Node Detection)。GPSR-HND协议中,转发节点通过空洞节点检测机制检测邻居节点状态,将有效邻居节点加入待选邻居节点集;然后基于层次分析法(Analytic Hierarchy Process,AHP)的多度量下一跳节点选择机制从待选邻居节点集中选择权重最大的邻居节点贪婪转发数据;如果待选邻居节点集为空,则从空洞邻居节点集中选择权重最大的空洞节点启动改进的周边转发机制,寻找可恢复贪婪转发模式的节点。与GPSR-NS协议和GPSR协议相比,GPSR-HND协议表现出了更好的性能,包括平均端到端时延和丢包率的改善,以及吞吐量的提高。

基于遗传算法和蚁群算法的LEACH改进协议

针对无线传感器网络低功耗自适应集簇分层(Low Energy Adaptive Clustering Hierarchy,LEACH)路由协议因能耗不均衡导致节点过早死亡的问题,提出了一种基于遗传算法和蚁群算法改进的LEACH路由协议。在分簇阶段,通过遗传算法选举合理的簇头节点并根据节点的分布划分簇群;在数据传输阶段,通过蚁群算法使簇头节点尽可能选择能量充足且距离较短的路径进行数据传输。仿真结果表明,与传统的分簇路由协议LEACH和LEACH-C相比,改进算法可以使网络的能量消耗更加均衡,并延长网络的生命周期。

基于快速原型化的小型涡喷发动机起动过程控制

为快速验证小型涡喷发动机起动过程控制规律,基于快速原型化技术搭建了半物理试验平台。设计了快速原型试验系统整体架构,对控制系统的软硬件设计和智能节点的工作原理进行了说明,使用Speedgoat Mobile实时目标机作为电子控制器,以STM32为核心设计智能节点,选用Modbus协议对信号进行编码,实现电子控制器和智能节点之间的数据通信。针对小型涡喷发动机的起动过程设计了一种控制规律,利用自动代码生成技术生成电子控制器可执行程序,部署到实时目标机中,完成了起动过程控制规律的试验验证。仿真结果表明,电子控制器和智能节点通信正常,工作可靠稳定,起动过程平稳迅速、不熄火、不超温、不超转,提出的快速原型化控制技术能够有效地缩短开发周期,具有良好的工程实用价值。

适用于水声传感器网络的混合路由协议

针对水声传感器网络中静态节点与移动节点不同路由设计需求,分析确定性路由和机会路由的特点,提出一种适用于水声传感器网络的混合路由协议(HRP-USN),将水声传感器网络区分为静态节点和移动节点开展设计。静态节点路由协议融合静态路由和动态路由优点,路由建立过程手动配置路由表,路由维护和重建过程采用联合MAC层反馈及聚焦转发控制的方式,兼顾自组织性和协议复杂性;移动节点采用机会路由,将数据以单跳方式发送到静态节点,自适应确定最优中继节点后按照已有路由传输到网关节点,利用水声信道广播特性,提升网络弱通信条件下数据包投递率。通过仿真分析,在不同节点移动速度和误码率条件下,HRP-USN数据包投递率明显优于其他传统路由协议,更加适合水声传感器网络。

LRCRaft:支持节点数据快速恢复的共识协议

在支持纠删码的分布式存储系统中,最常用的编码是RS(Reed-Solomon)码.对于一个RS(k,m)编码条带,常见的配置是一个节点仅存储条带中的一个分片,这导致在节点出现故障的情况下,对其存储分片的恢复需要跨多个节点读取分片并重新编码生成恢复分片,容易造成系统网络拥塞.在需要恢复大量数据的场合,系统在恢复期间会处于较长时间的脆弱期,容错能力和吞吐量下降、读写时延升高时有发生.LRCRaft是一个基于LRC(local reconstruction code)的改进Raft共识协议,通过在Raft中引入LRC码、动态日志增补、状态机删减和分片版本一致性等机制,降低了Raft的读写时延,缩短了节点故障恢复时间.实验结果表明,相较于Raft,LRCRaft在不同恢复模式中恢复一个单节点故障数据时,恢复用时有着49.25%–74.97%的减少.

一种板级多处理器间的高效通信方式

文章设计的协议方案通过建立虚拟设备节点的处理方式,在多个处理器、多台车辆接入通信时,在保证传输效率与正确性的同时,还能够显著降低代码量,提升代码复用率,大幅降低维护成本,提高车辆通信的服务品质。

Bidirectional Clone Node Model of Optimizing Performance of Structured P2P Overlay Network

In order to reduce the maintenance cost of structured Peer-to-Peer (P2P),Clone Node Protocol (CNP) based on user behavior is proposed.CNP considers the regularity of user behavior and uses the method of clone node.A Bidirectional Clone Node Chord model (BCNChord) based on CNP protocol is designed and realized.In BCNChord,Anticlockwise Searching Algorithm,Difference Push Synchronize Algorithm and Optimal Maintenance Algorithm are put forward to increase the performances.In experiments,according to the frequency of nodes,the maintenance cost of BCNChord can be 3.5%～32.5% lower than that of Chord.In the network of 212 nodes,the logic path hop is steady at 6,which is much more prior to 12 of Chord and 10 of CNChord.Theoretical analysis and experimental results show that BCNChord can effectively reduce the maintenance cost of its structure and simultaneously improve the query efficiency up to (1/4)O(logN).BCNChord is more suitable for highly dynamic environment and higher real-time system.

无线传感网LEACH协议的改进方法

为解决传统LEACH(Low Energy Adaptive Clustering Hierarchy)协议网络节点能量消耗高、存活数量少和生存寿命短等问题,提出了一种LEACH-AD改进方案。该算法引入最优簇头比率P值、加入距离因子、剩余能量因子和密度因子等因素更新的阈值公式进行分簇以及簇间的传输。实验结果表明,改进后的LEACH-AD协议在首个死亡节点、10%死亡节点以及全部死亡节点分别比原LEACH协议延长138轮、195轮、628轮。在能量消耗方面比原LEACH协议多持续了631轮,改进后的路由协议减少了网络节点的能量消耗量,从而有效延长了无线网络与传感节点的工作时间,这对无线监测系统的研究与开发意义重大。

Detection of Insider Selective Forwarding Attack Based on Monitor Node and Trust Mechanism in WSN

The security problems of wireless sensor networks (WSN) have attracted people’s wide attention. In this paper, after we have summarized the existing security problems and solutions in WSN, we find that the insider attack to WSN is hard to solve. Insider attack is different from outsider attack, because it can’t be solved by the traditional encryption and message authentication. Therefore, a reliable secure routing protocol should be proposed in order to defense the insider attack. In this paper, we focus on insider selective forwarding attack. The existing detection mechanisms, such as watchdog, multipath retreat, neighbor-based monitoring and so on, have both advantages and disadvantages. According to their characteristics, we proposed a secure routing protocol based on monitor node and trust mechanism. The reputation value is made up with packet forwarding rate and node’s residual energy. So this detection and routing mechanism is universal because it can take account of both the safety and lifetime of network. Finally, we use OPNET simulation to verify the performance of our algorithm.

An Improved AOMDV Routing Protocol for Airspace Communication Network

The airspace communication network based on spacecraft has a wide range of applications in regional information enhancement and emergency communication. In this paper, a routing algorithm for congestion degree detection of multipath routing (CD_AOMDV) is proposed. The method of combining the whole congestion degree detection and local congestion degree detection before service initiation is adopted. Timely and accurate judgment of the congestion degree reduced the loss rate of the hot nodes, so the average packet loss rate reduced. Simulation results show that compared with the traditional AOMDV protocol, the CD_AOMDV proposed in this paper has reduced the packet loss and improved delay performance, which is more suitable for the airspace communication network.

Receiver-Controlled Multi-Node Cooperation

Since wireless links in Ad hoc networks are more fragile than those in traditional wireless networks due to route flapping,multi-node cooperation plays an important role in ensuring the quality of service( QoS). Based on the authors' previous work,this paper proposes a receiver-controlled multi-node cooperation routing protocol,known as AODV-RCC. In this protocol,nodes form a cooperation group based on signal power. In a cooperation group,signal power between a partner and a transmitter,as well as signal power between the partner and the receiver,must be larger than the signal power between the transmitter and the receiver. Otherwise,the transmission will not benefit from cooperation. To avoid collision or congestion,each cooperation group only contains one partner. This partner offers both data and ACK cooperative retransmission. Its retransmission time should be shorter than the internal retry time of the transmitter's MAC layer,because it is better for the partner to retransmit firstly,as it offers a more reliable cooperative link. In AODV-RCC,it is the receiver that chooses the partner,because the link between the partner and the receiver is the most important. According to our simulation results,AODV-RCC shortens the end-to-end delay and increases the packet delivery ratio.

一种快速低开销的移动节点分布式寻路RPL路由协议

针对低功耗有损网络(Low Power and Lossy Network,LLN)中移动节点作为中继节点时,存在无线链路易断开、数据传输成功率较低和控制开销较高的问题,提出了一种快速低开销的移动节点分布式寻路RPL路由协议(Mobile Node Distributed Pathfinding RPL Routing Protocol,MNA-RPL)。首先,提出一种邻居表自适应更新机制,依据邻居表快速切换父节点;其次,提出一种父子节点双断开机制,能够有效减少数据包丢失;最后,提出一种基于速度动态管理的Trickle计时器,根据自身速度动态调整DIO广播周期。理论分析和仿真结果表明,与主流路由协议相比,该协议在数据传输和控制开销等方面的性能均有一定的提升。

Enhancing Delay in MANET Using OLSR Protocol

The performance of a Mobile Ad hoc Network (MANET) is closely related to the capability of the implemented routing protocol to adapt itself to unpredictable changes of topology network and link status. The Optimized Link State Routing (OLSR) protocol is a one key of the proactive routing protocols for MANETs. It is based on the multi-point relays (MPRs) technique to reach all nodes in the network with a limited number of broadcasts. In this paper, we propose new versions of the original OLSR protocol based on a new mobility parameter, in the goal to enhance and adapt it in the presence of the mobility. For this objective we define new three criterions for MPRs selection. The first criteria take for selection, just the mobility of nodes at one-hop. The two others criterions are based on both mobility of nodes at one-hop and two-hops.

铁路沿线线型无线传感器网络高效路由协议

为防止网络“热区”现象,针对铁路沿线无线传感器网络多呈线型分布的结构特点,提出一种基于服务质量的能耗均衡分簇路由协议(ECRPQ)。首先,部署网络节点,计算节点能量消耗,建立能耗均衡的非均匀节点部署模型并进行网络分簇。然后,设计路由协议,在簇首选举时引入节点动态剩余能量和节点担任簇首轮次的影响因素,在通信阶段采用TDMA机制和CDMA机制相结合的方式,在进行时间同步校准时严格保证簇内节点时间同步。最后,通过MATLAB进行仿真实验,从网络生命周期、网络吞吐量和节点平均时延3个方面将ECRPQ与LEACH、LEACH-C这2种经典协议进行对比。结果表明:当网络节点总数为200个时,ECRPQ的网络生命周期明显更长,达到600 s;ECRPQ的网络吞吐量更大,分别比LEACH和LEACH-C提高128.7%和84.6%;ECRPQ的节点平均时延更低,分别比LEACH和LEACH-C降低52.8%和43.2%。

一种水下接收端同步的并发媒体接入控制协议

针对水下声信号的低传播速度导致的时空不确定性问题,能够高效的利用水下声信道的长传播时延的信道预约技术,常被水下传感器网络的媒体接入控制协议的设计所采用,为了探索设计水下传感器网络的高性能媒体接入控制协议,以信道预约技术为基础,提出了一种新型的适用于移动水下传感器网络的,基于接收端同步的并发媒体接入控制协议,即CMACRS(concurrent medium access control based on receiver synchronization),新协议采用信道预约方法,实现了多个发送节点的并发传输。广泛的仿真结果显示,在吞吐量等性能方面,新协议优于非时隙级并发传输的水下媒体接入控制协议。

WSN中基于区域感知的改进AODV路由协议

AODV路由协议是无线自组网中的经典协议,适用于无线传感器网络(WSN)。但是该协议在路由发现阶段通过跳数建立路径,导致网络拥塞严重、部分节点过早失效以及活动路由频繁断裂,从而引起传输时延延长、路由开销增大、网络寿命缩短等问题。针对WSN中能量分布不均衡以及对邻居节点依赖性强的特点,提出基于区域感知的改进AODV路由协议。在路由发现阶段,引入QoS需求参数中的时延作为路径主权重,并计算区域变化率对路径主权重产生的正负增益,采用最优路径选择算法选取权重最小的路径,并将其作为最优路径。在路由维护阶段,通过计算区域能量和节点距离,丢弃区域中质量较差的节点,减少冗余拓扑和链路故障现象的发生。实验结果表明,相比传统的AODV协议,该协议的端到端时延和路由开销分别降低47.73%和48.00%,分组转发率和网络生存时间分别提升6.97%和14.80%。

无线网络中多址接入协议仿真测试

无线网络中的多址接入协议直接影响信道利用率和数据分组传输效率,为此对其展开研究。分析无线网络模型和CAP广播覆盖范围,通过调整智能天线模式使所有移动用户站点都能被光束覆盖;明确节点移动对数据分组收发的影响后,选择PB-AB FMA协议作为无线网络的多址接入协议。在协议中,CAP通过不断轮询节点完成数据分组的收发。对于待接入到信道中的新节点,通过竞争确定接入的优先级,当所有待接入节点都有对应的NEW时隙,且不再发生碰撞,即完成了无线网络多址接入协议的确定。在仿真测试中,所提方法较其它方法相比,有着最低的总信道利用率和平均信道利用率,可在不浪费信道资源的前提下,高效的完成数据分组收发任务。

基于簇头节点能量均衡选择的LEACH优化算法

针对无线传感网络中LEACH协议在进行簇头节点选择时能量消耗过快导致的生存周期短、数据吞吐量低等问题,提出了一种基于簇头节点能量均衡选择的LEACH优化算法。该算法选取WSNs中剩余能量高的普通节点作为簇头节点,同时考虑普通节点与簇头节点、簇头节点与基站之间的距离,以及所有节点的剩余能量和平均能量等因素来选择通信方式和传输路径。通过MATLAB工具,对提出的算法进行了仿真实验。结果表明,在100 m×100 m的小面积监测区域和200 m×200 m的大面积监测区域内,与LEACH、DEEC、IMP-LEACH算法相比,该算法降低了WSNs中节点的能量消耗,延长了生存周期,同时提高了数据吞吐量。