期刊文献+
共找到8篇文章
< 1 >
每页显示 20 50 100
全局结构引导的人造物体参数化基元检测
1
作者 陈柱瀚 黄惠 《计算机辅助设计与图形学学报》 EI CSCD 北大核心 2023年第11期1769-1779,共11页
点云是表达三维数据的常见形式,点云数据提取出的几何基元能够帮助人们快速地理解并处理场景信息,也方便后续其他任务的开展.为了更好地利用人造物体中普遍存在的全局结构关系,增强基元检测过程中全局结构的正向引导,提出参数化基元检... 点云是表达三维数据的常见形式,点云数据提取出的几何基元能够帮助人们快速地理解并处理场景信息,也方便后续其他任务的开展.为了更好地利用人造物体中普遍存在的全局结构关系,增强基元检测过程中全局结构的正向引导,提出参数化基元检测网络——RelationNet,包括2个子模块.首先,为了更好地编码三维点与其所在基元的结构关系,通过空间偏移预测模块预测三维点所在基元中心的偏移向量,提升点对其所在基元的位置感知能力,为后续分割任务提供更多的特征依据;其次,人造物体的基元与基元之间常常具有如平行、垂直、轴对齐等结构关系,为了更好地利用这些关系实现对几何基元检测结果的改进,还包含全局结构关系提取模块,利用基元拟合后获得的参数判断各个基元之间的结构关系,并通过设置相应的损失函数对提取到的结果进行引导监督.在大型ABC数据集与基元监督拟合(SPFN),ParseNet等主流算法进行对比的实验结果表明,RelationNet在基元分割和基元分类任务上的MIoU分别达到85.32%和90.10%,与当前先进方法相比有明显的效果提升. 展开更多
关键词 几何基元检测 全局结构关系 参数化
下载PDF
图像视觉条状纹理矢量方向场检测技术
2
作者 秦文 李在铭 《信息与电子工程》 2004年第4期252-255,296,共5页
方向场是条纹图像的重要特征量。本文提出了条纹图像矢量方向场模型,相比于通常的标量方向场,更符合方向的角度特性,并能通过矢量的模携带方向估计的锐度系数,使得对方向场的运算具有加权特性。同时,在矢量方向场的检测中,提出基元检测... 方向场是条纹图像的重要特征量。本文提出了条纹图像矢量方向场模型,相比于通常的标量方向场,更符合方向的角度特性,并能通过矢量的模携带方向估计的锐度系数,使得对方向场的运算具有加权特性。同时,在矢量方向场的检测中,提出基元检测的概念。实验表明,通过建立矢量方向场,能够更准确地描述条纹图像的方向特征,并且有利于图像的后续处理。 展开更多
关键词 信息处理技术 矢量方向场 基元检测 条状纹理 锐度系数
下载PDF
多形态布料仿真中与刚体的实时碰撞检测 被引量:3
3
作者 唐勇 严凯丽 +1 位作者 刘宇涵 吕梦雅 《小型微型计算机系统》 CSCD 北大核心 2016年第10期2347-2350,共4页
现实环境中布料存在多种形态并不可避免的与其他物体发生碰撞.为了丰富布料动画模拟的场景,采用不同硬度、不同分辨率、不同风速条件下的布料与物体发生碰撞,实时模拟多种条件下的布料动态场景,进一步提高布料动画模拟的实用性.首先,使... 现实环境中布料存在多种形态并不可避免的与其他物体发生碰撞.为了丰富布料动画模拟的场景,采用不同硬度、不同分辨率、不同风速条件下的布料与物体发生碰撞,实时模拟多种条件下的布料动态场景,进一步提高布料动画模拟的实用性.首先,使用改进后的质点弹簧模型对布料进行建模,有效减少了虚拟弹簧的种类数,提高了计算速度和算法的稳定性.其次,提出一种简单风场模型描述真实风场,将布料受力均匀离散到各个质点上,简化了计算的复杂性;再次,使用改进的基元相交检测算法检测布料质点与碰撞物体三角面是否相交,有效避免了误判的产生;最后,根据布料与物体碰撞后会发生能量的耗散原理,修正碰撞后质点的位置和速度,有效解决了布料与物体的碰撞响应问题,大大增强了布料动画模拟的真实感. 展开更多
关键词 布料模拟 风场 质点弹簧模型 基元相交检测 能量耗散
下载PDF
一种多关节机械臂运动过程中的碰撞检测方法 被引量:7
4
作者 王新达 韩宝玲 +1 位作者 陈禹含 郑凯林 《科学技术与工程》 北大核心 2019年第14期218-223,共6页
针对多自由度机械臂在运动过程中自身会发生碰撞的问题,建立机器人的简化模型(关节为球体,连杆为胶囊体),进而将多自由度机械臂的碰撞检测问题转化为简化后的几何模型(碰撞检测基元)之间的干涉计算问题。将此干涉问题进一步分解,最终转... 针对多自由度机械臂在运动过程中自身会发生碰撞的问题,建立机器人的简化模型(关节为球体,连杆为胶囊体),进而将多自由度机械臂的碰撞检测问题转化为简化后的几何模型(碰撞检测基元)之间的干涉计算问题。将此干涉问题进一步分解,最终转化为两球体之间、两胶囊体之间、球体与胶囊体之间的最小距离求解,并针对空间两胶囊体轴线之间距离计算问题,提出一种精确并快速的碰撞检测方法。将该算法实现并应用于6R串联机器人,最终利用MATLAB和ADAMS联合仿真进行验证。仿真结果验证了该算法的有效性。 展开更多
关键词 多关节机械臂 碰撞检测 检测基元 最小距离
下载PDF
Study on Agrobacterium tumefaciens-mediated Transformation of Brassica campestris L. with Fusion Gene Ycoil-bFGF
5
作者 徐岩 肖艳双 +4 位作者 杜金霞 汪洪 郑伟 李营 庞实锋 《Agricultural Science & Technology》 CAS 2009年第4期31-36,共6页
[ Objective] The study is to generate pharmaceutical protein via plant transgenic technique. [Methed] Using the cotyledons with petiole as transformation receptor, the fusion gene of rapeseed oil-body gene and bFGF wa... [ Objective] The study is to generate pharmaceutical protein via plant transgenic technique. [Methed] Using the cotyledons with petiole as transformation receptor, the fusion gene of rapeseed oil-body gene and bFGF was introduced into the rapeseed ( Brassica campestris L. ) by Agrobacterium tumefaciens-mediated transformation; meanwhile regeneration conditions of rapeseed were also optimized, and the regenerated resistant plantlets were detected by PCR and Southern blot. [ Result] This fusion gene had been integrated into rapeseed genome successfully, and the optimized conditions of transformation and regeneration were as follows: explants pre-culture for 2 d, co-culture for 3 d, bacteria solution OD600 for 0.3 and infection time for 5 min. [ Conclusion] The results laid a solid foundation for extraction, isolation and purification of protein in transgenic plant seeds. 展开更多
关键词 Basic fibroblast growth factor (bFGF) Plant bioreactor Oil-body system Agrobacterium tumefaciens Brassica campestris L.
下载PDF
Damage alarming for bridge expansion joints using novelty detection technique based on long-term monitoring data 被引量:4
6
作者 缪长青 邓扬 +1 位作者 丁幼亮 李爱群 《Journal of Central South University》 SCIE EI CAS 2013年第1期226-235,共10页
Damage alarming and safety evaluation using long-term monitoring data is an area of significant research activity for long-span bridges. In order to extend the research in this field, the damage alarming technique for... Damage alarming and safety evaluation using long-term monitoring data is an area of significant research activity for long-span bridges. In order to extend the research in this field, the damage alarming technique for bridge expansion joints based on long-term monitoring data was developed. The effects of environmental factors on the expansion joint displacement were analyzed. Multiple linear regression models were obtained to describe the correlation between displacements and the dominant environmental factors. The damage alarming index was defined based on the multiple regression models. At last, the X-bar control chart was utilized to detect the abnormal change of the displacements. Analysis results reveal that temperature and traffic condition are the dominant environmental factors to influence the displacement. When the confidence level of X-bar control chart is set to be 0.003, the false-positive indications of damage can be avoided. The damage sensitivity analysis shows that the proper X-bar control chart can detect 0.1 cm damage-induced change of the expansion joint displacement. It is reasonably believed that the proposed technique is robust against false-positive indication of damage and suitable to alarm the possible future damage of the expansion joints. 展开更多
关键词 damage alarming expansion joint TEMPERATURE traffic condition control chart suspension bridge
下载PDF
彩色车牌图像转换成可识别的二值化字符的一种新的算法
7
作者 韩配富 王航楠 +1 位作者 李忠君 王洋 《电子技术(上海)》 2009年第4期32-34,共3页
现有的在显示设备上的数字图像处理系统上进行的,是将连续的模拟图像变成离散的数字图像后,用建立在特定的物理模型和数学模型基础上编制的程序(软件)控制,运行并实现种种要求的处理。提出了一种新的算法可以更好的将彩色车牌图像进行... 现有的在显示设备上的数字图像处理系统上进行的,是将连续的模拟图像变成离散的数字图像后,用建立在特定的物理模型和数学模型基础上编制的程序(软件)控制,运行并实现种种要求的处理。提出了一种新的算法可以更好的将彩色车牌图像进行处理并将其变成可识别的二值化图像。 展开更多
关键词 数字图像处理 基元检测 二值化 灰度处理
原文传递
NIPAD: a non-invasive power-based anomaly detection scheme for programmable logic controllers 被引量:4
8
作者 Yu-jun XIAO Wen-yuan XU +2 位作者 Zhen-hua JIA Zhuo-ran MA Dong-lian QI 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2017年第4期519-534,共16页
Industrial control systems (ICSs) are widely used in critical infrastructures, making them popular targets for attacks to cause catastrophic physical damage. As one of the most critical components in ICSs, the progr... Industrial control systems (ICSs) are widely used in critical infrastructures, making them popular targets for attacks to cause catastrophic physical damage. As one of the most critical components in ICSs, the programmable logic controller (PLC) controls the actuators directly. A PLC executing a malicious program can cause significant property loss or even casualties. The number of attacks targeted at PLCs has increased noticeably over the last few years, exposing the vulnerability of the PLC and the importance of PLC protection. Unfortunately, PLCs cannot be protected by traditional intrusion detection systems or antivirus software. Thus, an effective method for PLC protection is yet to be designed. Motivated by these concerns, we propose a non-invasive power- based anomaly detection scheme for PLCs. The basic idea is to detect malicious software execution in a PLC through analyzing its power consumption, which is measured by inserting a shunt resistor in series with the CPU in a PLC while it is executing instructions. To analyze the power measurements, we extract a discriminative feature set from the power trace, and then train a long short-term memory (LSTM) neural network with the features of normal samples to predict the next time step of a normal sample. Finally, an abnormal sample is identified through comparing the predicted sample and the actual sample. The advantages of our method are that it requires no software modification on the original system and is able to detect unknown attacks effectively. The method is evaluated on a lab testbed, and for a trojan attack whose difference from the normal program is around 0.63%, the detection accuracy reaches 99.83%. 展开更多
关键词 Industrial control system Programmable logic controller Side-channel Anomaly detection Long short-term memory neural networks
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部