Application of Wireless Local Area Network Technology in Mobile Robot for Finned Tube Inspection

This paper introduces a novel robot for outer surface inspection of boiler tubes. The paper describes the hardware system, wireless communication strategy, communication procedure and system software of the robot. The WLAN technology is used in the robot. It solves the problem of shielding generated by iron boiler and 11Mbps bandwidth made it possible for video and control stream real-time transmit within the same channel. Though TCP/IP protocol is robust, serial server is a transparent channel but cannot detect error and retransmit the data. In order to improve the reliability of serial communication, a new communication protocol is proposed. Key words boiler tubes - mobile robotics - wireless local area network Project Supported by the National High-Tech Program (Grant No. 2002AA420080)

Security Analysis of Application Layer Protocols on Wireless Local Area Networks

This paper aims at analyzing the security issues that lie in the application layer (AL) protocols when users connect to the Internet via a wireless local area network (WLAN) through an access point. When adversaries launch deauthentication flood attacks cutting users' connection, the connection managers will automatically research the last access point's extended service set identifier (ESSID) and then re-establish connection. However, such re-connection can lead the users to a fake access point with the same ESSID set by attackers. As the attackers hide behind users' access points, they can pass AL's authentication and security schemes, e.g. secure socket layer (SSL). We have proved that they can even spy on users' account details, passwords, data and privacy.

Optical local area network emulations over Ethernet passive optical networks:A survey

As a promising solution to efficiently achieving fiber to the home （FTTH）, Ethernet passive optical network （EPON） is currently improved to provide intercommunication among customers, together with normal traffic delivery, via optical local area network emulation. It is a new research direction and expected to enhance the normal EPON performances. The purpose of this article is to review the state-of -the-art solutions to emulating optical local area networks （OLANs） over EPON. We discuss the major problems involved, e.g., network architecture, control mechanisms, and other potential enhancements. We also outline areas for future researches.

STAR-TYPE LOCAL AREA NETWORK ACCESS CONTROL

The multiple access fashion is a new resolution for the star-type local area network (LAN) access control and star-type optical fibre LAN. Arguments about this network are discussed, and the results are introduced.

Multiple Welding Seam Video Transmission and Monitoring of Welding Robot in Local Area Network

A method of transmission and monitoring in local area network(LAN) for the welding seam video information of binocular vision welding robot is proposed.This paper uses MPEG-4 video CODEC functions of DivX,video for Windows(VFW) video capture technology,multi-threaded network communication idea and WinSock Socket in Visual C++ 6.0.In the end,client/server(C/S) communication model based on TCP/IP protocol has been developed.Experimental results show that the method can achieve the multiple welding seam video's real-time transmission in LAN.Moreover,the Canny operator is used to realize the edge feature extraction of the seam image which is captured by the client,so that the edge of the seam extracted is continuous and clear.

HUSTRING—A LOCAL AREA NETWORK WITH PERFORMANCE BETTER THAN TOKEN RING

HUSTRING, a local area network named after the Harbin University of Science and Technology, uses a combination of token-passing approach and register insertion technology as its medium access control mechanism. The results of theoretical analysis and computer simulation indicate that the real-time performance of the HUSTRING is much better than that of the well-known token-ring local area network.The network topology of the HUSTRING, the architecture of its physical layer, medium access layer and logic link layer and the configuration of its ring interface are describedand its performance is compared with the token ring local area network.

基于local-area的Internet路由级拓扑抽象算法

通过分析Internet的本地聚集特性，给出了local-area和connect—area的定义，并基于此，为提高并行网络模拟性能，提出一种新型拓扑抽象算法——基于local—area的拓扑抽象（TABLA）算法。TABLA算法在给定的聚合粒度下，迭代搜索网络内的local-area，对拓扑进行抽象。模拟结果表明在Internet路由级拓扑上采用该算法，拓扑规模大约压缩为原先的45％，初始化内存节省约60％，模拟运行时间约缩短80％，大幅度提高了并行网络模拟性能。

Resource Exhaustion Attack Detection Scheme for WLAN Using Artificial Neural Network

IEEE 802.11 Wi-Fi networks are prone to many denial of service(DoS)attacks due to vulnerabilities at the media access control(MAC)layer of the 802.11 protocol.Due to the data transmission nature of the wireless local area network(WLAN)through radio waves,its communication is exposed to the possibility of being attacked by illegitimate users.Moreover,the security design of the wireless structure is vulnerable to versatile attacks.For example,the attacker can imitate genuine features,rendering classificationbased methods inaccurate in differentiating between real and false messages.Althoughmany security standards have been proposed over the last decades to overcome many wireless network attacks,effectively detecting such attacks is crucial in today’s real-world applications.This paper presents a novel resource exhaustion attack detection scheme(READS)to detect resource exhaustion attacks effectively.The proposed scheme can differentiate between the genuine and fake management frames in the early stages of the attack such that access points can effectively mitigate the consequences of the attack.The scheme is built through learning from clustered samples using artificial neural networks to identify the genuine and rogue resource exhaustion management frames effectively and efficiently in theWLAN.The proposed scheme consists of four modules whichmake it capable to alleviates the attack impact more effectively than the related work.The experimental results show the effectiveness of the proposed technique by gaining an 89.11%improvement compared to the existing works in terms of detection.

农机具田间试验动态遥测系统设计

针对当前农机具田间试验参数检测技术薄弱、无法全面综合评估农机关键部件作业性能的情况,设计了农机具田间试验的遥测系统。在当前农机具三点悬挂连接方式利用上拉杆拉压力传感器、下悬挂销剪切力传感器、角传感器、动态扭矩传感器等实现机具作业过程中的多分量力有效检测。系统检测终端采用STM32F429单片机为主核心芯片,设计了多通道传感器数据融合同步采集处理电路、以太网处理电路及外部输出电路等,可实时对前端传感器数据进行采集、处理及存储,并采用RTK差分定位系统准确检测机组的作业速度及位置,通过大功率WiFi模块经局域网络将作业参数实时传输给田间远程监测平台。用户可通过上位机软件实现对作业参数进行计算存储、曲线绘制、时域分析、统计设置等。测试结果表明:系统结构简单,检测精度高,能够实现机具作业同步受力分析及技术参数测量,可作为田间试验的有效检测手段。

基于自发数据传输的高效双LAN太赫兹无线局域网MAC协议

针对现有的双局域网(LAN)太赫兹无线局域网(Dual-LAN THz WLAN)相关介质访问控制(MAC)协议中存在的某些节点会在多个超帧内重复发送相同的信道时隙请求帧以申请时隙资源以及网络运行的一些时段存在空闲时隙等问题,提出一种基于自发数据传输的高效MAC协议——SDTE-MAC(high-Efficiency MAC protocol based on Spontaneous Data Transmission)。SDTE-MAC通过让各节点都维护一张或多张时间单元链表,使各节点与其余节点在网络运行时间上达到同步,从而获悉各节点应该在信道空闲时隙的什么位置开始发送数据帧,优化了传统的信道时隙分配和信道剩余时隙再分配的流程,提高了网络吞吐量和信道时隙利用率,降低了数据时延,能够进一步提升双LAN太赫兹无线局域网的性能。仿真结果表明,网络饱和时,相较于AHT-MAC(Adaptive High Throughout multi-pan MAC protocol)中的N-CTAP(Normal Channel Time Allocation Period)时段时隙资源分配新机制以及自适应缩短超帧时段机制,SDTE-MAC的MAC层吞吐量提升了9.2%,信道时隙利用率提升了10.9%,数据时延降低了22.2%。

模态分解下的无线局域网室内全覆盖通信方法

室内无线局域网的覆盖率是影响用户网络通信效率的关键因素。若室内面积越大以及墙体过厚,且终端使用环境密封会导致通过折射等途径传输通信信号非常微弱,严重影响无线局域网的通信覆盖范围。为此,提出模态分解下的无线局域网室内全覆盖通信方法。通过划分局域网模态单元和确定室内信号振幅阈值,构建模态振幅阈值模型,消除无线局域网室内信号滤波噪声。从终端无线访问节点(AccessPoint,AP)的信号容量和天线传播损耗两方面分析影响无线局域网通信覆盖范围的原因。基于此,利用非朗伯发射器扩充无线局域网终端AP的信号容量,实现无线局域网的室内全覆盖通信。实验结果表明,研究方法应用下无线局域网的室内通信的盲点面积小,覆盖效率更高,实验场景室内通信信息传输率约为6.8Mbit·s^(-1),说明上述方法的可应用性更强。

基于BEGAN的汽车CAN网络入侵检测数据增强方法研究

针对目前汽车CAN网络入侵检测算法因攻击样本缺少而导致数据不平衡问题,提出一种基于BEGAN的CAN入侵检测数据增强方法,引入one-hot编码将CAN报文特征图像化,结合构建的生成对抗网络,生成与真实攻击格式一致且内容差异的有效样本。通过采集实车数据作为真实样本进行训练,从特征图、t-SNE可视化、统计学分析和分类器验证角度验证了所生成的增强数据集的实用性,可提高入侵检测分类器准确率;与传统过采样算法含随机过采样(ROS)、合成少数过采样(SMOTE)、SMOTE-ENN、自适应合成过采样(ADASYN)相比,具有更高的准确率。

基于STM32的塔机数据采集和监控系统设计

针对塔机作业对运行状态参数和作业环境实时监测的需求,设计了一种基于STM32的塔机数据采集和监控系统。该系统采用STM32F103RCT6为核心的微处理器对塔机运行各项状态参数结合传感器进行数据采集和处理,传感器信号经带数字隔离的A/D转换模块和RS485转TTL模块传输到微处理器,微处理器通过串口转以太网模块将采集的传感器数据发送到由工业交换机和网络摄像机组建的局域网中。最后,采用Java语言结合Spring Boot框架开发系统上位机页面对传感器数据和视频监控画面进行显示。通过测试,该系统能够对塔机运行状态参数和塔机作业环境进行实时监测,传感器采集数据的平均相对误差为0.74%,摄像机监控画面平均延时20.4 ms,实现了数据高速准确的实时监测,满足了监测塔机的系统需求。

地方性与现代性:江南水网乡村景观空间特征与文脉传承

人居环境“地方性”侧重立足本土特质的空间表达,“现代性”倾向立足功能主义的空间表达,二者看似矛盾,实则相辅相成。基于“地方性”与“现代性”辩证统一的视角,评析1984–2023年国内有关江南水网乡村景观空间特征与文脉传承研究进展。基于筛选获得的498篇有效文献,首先运用文献计量分析识别出研究热点方向,包括景观空间形态认知、演变认知、价值认知、机制认知以及景观文脉传承的理论研究、实践探索共6个方面。在进一步分析文献内容的基础上,分别评述各个热点方向的研究内容进展,并针对研究局限提出5点研究展望,分别是构建景观空间形态认知框架、扩展景观空间演变研究内容、探索景观空间多元价值评价体系、重视景观空间机制“过程”研究,以及搭接文脉传承理论研究与实践探索之间的桥梁。以期能为江南水网乡村景观空间特征与文脉传承相关研究提供借鉴,为该地区乡村景观规划设计实践提供理论参考。

基于IRF-PF算法的WLAN室内定位方法

针对室内复杂环境下无线局域网接收信号强度的时变波动性,提出一种基于改进随机森林算法并融合粒子滤波的室内定位方法。首先,通过自适应滑动窗口选取接收信号强度较为平滑的信号接入点作为定位指纹特征建立决策树,从而减少特征空间的噪声;然后,利用bagging抽样后的袋外数据赋予决策树不同的投票权重等级,增大决策树类别间判别差异性,优化随机森林算法在目标位置与接收信号强度间弱映射关联性场景下定位精度低的问题,依据改进的随机森林算法建立位置坐标与接收信号强度间的映射模型,计算定位点的位置;最后,为了提高定位准确性与稳定性,将依据改进随机森林算法计算出的位置作为粒子滤波的观测量,利用粒子滤波对目标位置进行估计和预测。在Zenodo数据集上的实验结果表明:提出的算法在定位误差2 m范围内精度达到75.8%,在4 m范围内精度已经高达94.8%;相比于传统随机森林算法,能够将2 m内的定位精度提高11.5%;与K近邻、岭回归和贝叶斯等室内定位算法相比,定位精度和算法实时性也得到明显提升。

联合特征概率分布和时间相关性的无线网络业务建模方法

民用无线网络以及航空无线网络等未来无线网络需要承载需求多样化的业务类型和信息交互。数据包尺寸特征和数据包到达间隔等不同业务特征,对无线网络有至关重要的意义。然而,当前无线网络业务建模研究鲜有同时建模业务特征和业务特征的时间相关性,这导致对业务的建模刻画不够准确。本文提出一种联合业务特征概率分布和时间相关性的无线网络业务建模方法,保障了业务特征的概率分布和业务特征的时间相关性。本方法具有一般性,可以应用于民用无线网络的业务建模,也可以应用到航空无线领域,有利于对业务特性的把握,从而进行更加优化和确定性的资源分配。

Radio map updated method based on subscriber locations in indoor WLAN localization

With the rapid development of wireless local area network （WLAN） technology, an important target of indoor positioning systems is to improve the positioning accuracy while reducing the online calibration effort to overcome signal time-varying. A novel fingerprint positioning algorithm, known as the adaptive radio map with updated method based on hidden Markov model （HMM）, is proposed. It is shown that by using a collection of user traces that can be cheaply obtained, the proposed algorithm can take advantage of these data to update the labeled calibration data to further improve the position estimation accuracy. This algorithm is a combination of machine learning, information gain theory and fingerprinting. By collecting data and testing the algorithm in a realistic indoor WLAN environment, the experiment results indicate that, compared with the widely used K nearest neighbor algorithm, the proposed algorithm can improve the positioning accuracy while greatly reduce the calibration effort.

基于VLAN的多信道卫星通信地面系统设计

随着卫星通信技术的日益发展,系统内部多信道并存的现象越来越普遍,信道间传输的业务容易引起相互干扰,单纯运用传统路由器很难完成系统中不同信道间的业务完整隔离;同时,多信道卫星通信系统网络拓扑结构复杂,易引起控制混乱等问题。针对这些问题,提出一种基于虚拟局域网(Virtual Local Area Network,VLAN)的多信道卫星通信地面系统的设计方法。该方法充分利用网络划分VLAN技术的隔离性和安全性特征,结合多信道通信技术使用多个信道同时传输业务的特征,提升特征维度,实现高效、可靠的多信道卫星通信,具有易于硬件实现的特点,提高网络通信的吞吐量。

A Semi-Supervised WLAN Indoor Localization Method Based on l1-Graph Algorithm

For indoor location estimation based on received signal strength( RSS) in wireless local area networks( WLAN),in order to reduce the influence of noise on the positioning accuracy,a large number of RSS should be collected in offline phase. Therefore,collecting training data with positioning information is time consuming which becomes the bottleneck of WLAN indoor localization. In this paper,the traditional semisupervised learning method based on k-NN and ε-NN graph for reducing collection workload of offline phase are analyzed,and the result shows that the k-NN or ε-NN graph are sensitive to data noise,which limit the performance of semi-supervised learning WLAN indoor localization system. Aiming at the above problem,it proposes a l1-graph-algorithm-based semi-supervised learning( LG-SSL) indoor localization method in which the graph is built by l1-norm algorithm. In our system,it firstly labels the unlabeled data using LG-SSL and labeled data to build the Radio Map in offline training phase,and then uses LG-SSL to estimate user's location in online phase. Extensive experimental results show that,benefit from the robustness to noise and sparsity ofl1-graph,LG-SSL exhibits superior performance by effectively reducing the collection workload in offline phase and improving localization accuracy in online phase.