基于测距的无线传感网络定位方法

为了在无线传感网络中实现简单可靠的定位,采用节点与节点间直接测距的方式.研究了使用双边对称测距法来进行两点间的测距,并建立了一种测距同步的机制.根据测得的锚节点与目标节点间的距离,使用一种几何算法,来对目标节点的位置进行解算.     

The Effects of Visual and Auditory Models on the Learning of a Rhythmical Synchronization Dance Skill

The purpose of this study was to investigate the effect of visual and auditory concurrent models on the acquisition of a rhythmical synchronization task. Subjects attempted to synchronize a series of dance steps to the beat of two auditory rhythms. Subjects performed five trial blocks in one of four practice conditions: (a) audio-visual (auditory rhythms combined with a visual model), (b) audio-auditory (auditory rhythms combined with an auditory model), (c) auditory only (auditory rhythms with no model), and (d) visual only (no auditory rhythms but exposure to a visual model). Rhythmical timing and synchronization accuracy served as the dependent variables. Results revealed no practice condition learning differences for rhythmical timing. For synchronization accuracy, the audio-auditory group produced significantly lower error scores at acquisition, but no differences were found at retention. Apparently, the availability of models created an information dependency that resulted in a decrease of performance and, consequently, no group differences in retention.     

中国边境省区入境旅游发展的时间同步性与区域响应

依据1980—2011年中国边境9省区入境旅游客流量和旅游收入数据,分析其入境旅游发展的时间同步性与区域响应,结果表明:中国边境省区入境旅游可分为1980—1991年的缓慢增长期、1992—2003年的快速增长期和2004—2011年的加速增长期3个发展阶段;边境9省区入境旅游的增长变化、波动周期大致相同,但相关系数较低;各边境省区入境旅游发展还存在着较大的差异。依据基准年数值划分边境各省区各阶段入境旅游发展的起点,依据平均增速划分边境各省区各阶段入境旅游的发展速度,可动态地刻画不同省区不同阶段入境旅游的发展态势,揭示各省区入境旅游发展的区域响应,并为各省区入境旅游发展的动态比较研究和旅游发展规划制定提供参考依据。     

DVB-S2 inner receiver design for broadcasting mode

INTRODUCTION The second generation satellite digital video broadcasting standard (ETSI, 2004) has come out recently. Compared with the previous satellite stan-dard DVB-S (ETSI, 2003), DVB-S2 has more ad-vantages, such as the 30% increase in channel capac-ity, the more reliable performance, and the more ef-ficient usage of transponders. The DVB-S2 standard has been designed having in mind the peculiarities of the satellite channel, particularly the link fading im-pairments and the …     

星型网络中的混沌同步

Using an example,it was analytically proved that the dynamical systems constructed on a star coupled network is more easy to be synchronized than that in coupled map lattices(CML).The result shows that the synchronization in small-world networks may be realized more easily.     

异构数据库更新同步研究与实现

数据库同步是实现不同系统之间数据共享的有效方法。现有异构数据库同步模型能有效解决记录的同步新增,但由于同步记录查询基于数据表名和关键字值,若不考虑同步数据库节点变化,将导致数据库不适用于某些遗留系统。针对该问题,提出同步控制和主从记录映射方法,在同步控制层记录主从记录映射关系。在采用双向中间件方法的同步技术基础上,设计基于标准数据格式的数据转换,降低数据转换模块开发维护成本,并根据模型应用WCF框架实现系统。实践应用表明,该模型可实现异构数库之间同步更新。     

基于视频桥墩防撞预警系统的软件设计

通过分析摄像机传回的视频图像,实现对桥墩防撞的预警。用摄像机获取当前江面图像,利用图像处理技术,识别过往船舶;通过摄像机测距技术,测量船舶与桥墩的相对位置,起到预警作用。     

Distance Education in the Rural K-12 Environment

Abstract

A small rural school in Idaho tried various forms of distance education to broaden the range of subjects offered to students. It gave up on satellite-based coursework because of high cost and synchronization problems. Correspondence courses solved the synchronization problem, but still required expensive adult supervision to keep students on task. IP-based videoconferencing appeared to promise lower costs and better synchronization, but in practice it proved to be difficult to implement and exhausting for course teachers. The school began to view videoconferencing in terms of its enrichment and collaboration values. The Internet, together with other distance education technologies, may one day erase the educational disadvantages of rural isolation. They also promise to make lifelong learning the expected norm.     

用旋转相量分析振荡器的强迫同步现象

用旋转相量分析了振荡器的强迫同步现象 ,并给出了强迫同步频带宽度     

Java的多线程动画技术

讨论了网络教学软件中原始图像的加载问题,给出了一种高效正确的多线程解决方案和其例程片断。