基于Host Link网络的气体浓度报警控制系统

在冶金行业和石油化工行业生产过程中可能产生或使用易燃易爆气体,利用PLC和上位机组成的Host Link网络系统能实现气体浓度自动监测和报警。采用“三取二”原则、空气取样、系统自检等措施提高了系统可靠性。     

隧道反光环清洗机器人的设计与实验研究北大核心

为解决隧道反光环清洗困难的问题,设计一种隧道反光环自动清洗机器人。分别对机器人主框架、行走装置、清洗装置和智能检测系统等部分进行了规划与设计,确定各部分的主要功能和实现方式,并利用ANSYS Workbench对主框架进行静力学分析。机器人样机真实隧道环境实验结果表明:该隧道反光环清洗机器人结构与控制设计合理,工作状况良好,在不影响隧道正常通车的情况下完成了反光环的清洗。     

数控车床碰撞检测系统中NC程序检错与纠错模块的开发

讨论了对NC程序进行检错的意义，提出了数控车床碰撞检测系统的总体结构，包括机床、夹具等加工环境。以及与CAD软件的集成模块。介绍了NC程序的特点，并在VC6．0环境下开发了NC程序检错与纠错模块．通过设计数据结构解决了碰撞检查过程中工件不断变化的难题，为进一步具体研究奠定了基础。     

20G钢氢腐蚀的超声背散检测

选用20G低碳钢,经450℃和500℃,18MPa氢气中分别暴露240,480和720小时,使材料发生不同程度氢腐蚀,用背散法对氢蚀进行了超声波检测结果表明,背散法对氢蚀程度非常敏感,用杂草波平均高度与原始波高之比做为信噪比,能很好地反映氢蚀程度,论证了用背散法检测氢蚀程度的可能性.     

Subpixel accuracy for extracting groove center based on corner detection

0IntroductionWelds quality is directly affected by the location accu-racy of welding torch to groove center in vision sensor robotwelding. Therefore, it is very significant to increase theextraction accuracy of groove center. A common method isto use high resolution CCD and high speed image collectingcard, but it costs high or sometimes there are limits inuse.Subpixel detection is an effective soft method to in-crease image location accuracy[1 -2]. Compared with chan-ging hardwares , it is v…     

芦村旧排站电气设备现场安全检测

东莞市芦村旧排站主要电气设备有6台130 k W低压电动机、3台变压器、2台配电柜和6台启动柜,经过几十年的运行,设备老化严重,经过现场安全检测,技术指标不能满足要求,应进行更新改造。     

DOBNet: exploiting the discourse of deception behaviour to uncover online deception strategies

Online deception is fuelled by the escalated penetration of the Internet and social media. As the threat of online deception increases, understanding deception behaviour and underlying strategies is having a greater social impact. The verbal behaviour of online deception has recently been extended to the discourse level; nevertheless, discourse behaviours have been examined in isolation without referring to other behaviours in the discourse. By conceptualising the discourse of online behaviour as a social network (DOBNet), this research investigates possible impacts of deception intent on the central structures of DOBNet at three different levels: the discourse behaviour, subnetwork, and whole network. The empirical results of discourse network analysis and statistical tests provide partial support for each of the hypothesised effects. The findings not only demonstrate the efficacy of discourse in distinguishing deceivers from truth-tellers but also extend deception theories by confirming deception strategies from the perspective of discourse network and by uncovering unique characteristics of online deception strategies.     

Guided Volume Editing based on Histogram Dissimilarity

Segmentation of volumetric data is an important part of many analysis pipelines, but frequently requires manual inspection and correction. While plenty of volume editing techniques exist, it remains cumbersome and errorprone for the user to find and select appropriate regions for editing. We propose an approach to improve volume editing by detecting potential segmentation defects while considering the underlying structure of the object of interest. Our method is based on a novel histogram dissimilarity measure between individual regions, derived from structural information extracted from the initial segmentation. Based on this information, our interactive system guides the user towards potential defects, provides integrated tools for their inspection, and automatically generates suggestions for their resolution. We demonstrate that our approach can reduce interaction effort and supports the user in a comprehensive investigation for high‐quality segmentations.     

基于轮廓几何稀疏表示的刚性目标模型及其分级检测算法

刚性目标轮廓具有明显几何特性且不易受光照、纹理和颜色等因素影响.结合上述特性和图像稀疏表示原理,提出一种适用于刚性目标的分级检测算法.在基于部件模型(Part-based model, PBM)的框架下,采用匹配追踪算法将目标轮廓自适应地稀疏表示为几何部件的组合,根据部件与目标轮廓的匹配度,构建描述部件空间关系的有序链式结构.利用该链式结构的有序特性逐级缩小待检测范围,以匹配度为权值对各级部件显著图进行加权融合生成目标显著图. PASCAL图像库上的检测结果表明,该检测方法对具有显著轮廓特征的刚性目标有较好的检测结果,检测时耗较现有算法减少约60%~90%.     

一种基于OpenFlow的SDN访问控制策略实时冲突检测与解决方法

软件定义网络SDN(Software-Defined Networking)是由美国斯坦福大学Clean Slate研究组提出的一种新型网络创新架构,可通过软件编程的形式定义和控制网络,其控制平面和转发平面分离及开放性可编程的特点,为新型互联网体系结构研究提供了新的实验途径,也极大地推动了下一代互联网的发展.OpenFlow是SDN的主要协议,定义了SDN控制器与交换机之间的通信标准.目前,很多基于OpenFlow的SDN设备已经在实际中得到了部署.但是,基于OpenFlow的SDN却面临很多安全挑战.其中一个重要的挑战是如何建立一个安全可靠的SDN防火墙应用.由于OpenFlow协议的无状态性,现有的SDN防火墙可以被通过改写交换机中的流表项轻松绕过.针对这一安全威胁,作者提出了基于Flowpath的实时动态策略冲突检测与解决方法.通过获取实时的SDN网络状态,能够准确地检测防火墙策略的直接和间接违反,并且一旦发现冲突,可以基于Flowpath进行自动化和细粒度的冲突解决.最后,作者在开源控制器Floodlight上实现了一个安全增强的防火墙应用FlowVerifier,并基于Mininet对FlowVerifier的性能进行了评估.结果表明FlowVerifier能够检测和自动化地解决SDN网络中由于流表改写而引入的策略冲突及其带来的安全威胁.