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排序方式: 共有179条查询结果,搜索用时 15 毫秒
41.
提出了一种基于人眼视觉特性的小波变换数字水印算法,该算法能够依据人眼视觉特性,将水印信息嵌入到小波变换域的不同尺度、不同方向分量上,从而提供检测局部空域和频域变化的能力,实现局部水印和全局水印之双重目的.实验结果表明:所提出的数字水印不仅具有较好的透明性,而且对诸如剪切、低通滤波等攻击均具有较好的鲁棒性. 相似文献
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The group-cycling behaviours of over 16,000 members of the London Cycle Hire Scheme (LCHS), a large public bikeshare system, are identified and analysed. Group journeys are defined as trips made by two or more cyclists together in space and time. Detailed insights into group-cycling behaviour are generated using specifically designed visualization software. We find that in many respects group-cycle journeys fit an expected pattern of discretionary activity: group journeys are more likely at weekends, late evenings and lunchtimes; they generally take place within more pleasant parts of the city; and between individuals apparently known to each other. A separate set of group activity is found, however, that coincides with commuting peaks and that appears to be imposed onto LCHS users by the scheme’s design. Studying the characteristics of individuals making group journeys, we identify a group of less experienced LCHS cyclists that appear to make more spatially extensive journeys than they would do normally while cycling with others; and that female cyclists are more likely to make late evening journeys when cycling in groups. For 20% of group cyclists, the first journey ever made through the LCHS was a group journey; this is particularly surprising since just 9% of all group cyclists’ journeys are group journeys. Moreover, we find that women are very significantly (p < 0.001) overrepresented amongst these ‘first time group cyclists’. Studying the bikeshare cyclists, or bike share ‘friends’, that individuals make ‘first time group journeys’ with, we find a significantly high incidence (p < 0.001) of group journeys being made with friends of the opposite gender, and for a very large proportion (55%) of members these first ever journeys are made with a friend that shares the same postcode. A substantial insight, then, is that group cycling appears to be a means through which early LCHS usage is initiated. 相似文献
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Jenhwa Guo 《Journal of Marine Science and Technology》2008,13(2):147-153
This study presents a localization system using visual information for guidance and navigation of a biomimetic autonomous
underwater vehicle (BAUV). The BAUV tracks a mooring cable using two cameras and sonar. Sonar has good accuracy in detecting
longitudinal distances but is poor in detecting lateral distances. Since a stereo image has quantization errors, for the cameras,
measurement errors in lateral directions are less than those in the optic-axis direction. An extended Kalman filter was employed
to combine observational information derived from the cameras and sonar of the mooring cable position with the navigation
data of the BAUV. This work demonstrates, using water tank experiments, the effectiveness of the proposed tracking technique
in decreasing uncertainty in position estimations of the BAUV and mooring cable. 相似文献
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李兴田 《兰州交通大学学报》2011,30(1)
基于Intel Visual Fortran编译器,充分利用Fortran语言在数值计算方面的优势,结合业界优秀的OpenGL图形函数库,开发了可用于土木工程设计计算及其仿真的OpenGL框架,避免了其他语言和Fortran混合编程的复杂性,为工程仿真系统的开发提供了便捷的思路. 相似文献
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介绍上位机与欧姆龙V600系列RFID控制器串行通信连接方式、通信命令和通信数据帧格式.阐述了在VB环境下使用MSComm控件实现上位机与RFID控制器串行通信的方法,并给出了串口初始化、发送数据及串口事件处理程序代码.此方法为进一步开发RFID应用系统提供了有价值的参考. 相似文献
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陈亚梅 《广东交通职业技术学院学报》2007,6(4):40-41,45
文中主要介绍Visual Basic在实现PC与单片机89C51之间串行通讯中的应用。 相似文献