Medium access control( MAC) protocol of underwater acoustic communication network is a key technology for underwater acoustic networks( UANs). Most of the MAC protocols for wireless terrestrial communication networks ...Medium access control( MAC) protocol of underwater acoustic communication network is a key technology for underwater acoustic networks( UANs). Most of the MAC protocols for wireless terrestrial communication networks have been designed with negligible propagation delay. If it is deployed directly in an underwater environment,the UANs will perform inefficiently. In this paper,the characteristics of underwater acoustic channel are modeled and simulated by using the OPNET simulation tool,which are the speed of sound, propagation loss, and four sources for ambient noise: the turbulence,shipping,wind driven waves and thermal noise. The performance of pure Aloha( P-Aloha),carrier sense multiple access with collision avoidance( CSMA / CA) and multiple access collision avoidance for wireless local area network( MACAW) protocols in underwater acoustic channel environment are evaluated. The different performance of protocols in underwater environment is compared in the simulation.展开更多
针对煤矿下复杂环境及其安全管理需求,提出一种基于WLAN(Wireless Local Area Network)的全景视觉煤矿安全监控系统,采用ODVS(Omni-Directional Vision Sensors)配合有线和无线通信方式传输图像、信息、指令和数据,实时获取、传输井下...针对煤矿下复杂环境及其安全管理需求,提出一种基于WLAN(Wireless Local Area Network)的全景视觉煤矿安全监控系统,采用ODVS(Omni-Directional Vision Sensors)配合有线和无线通信方式传输图像、信息、指令和数据,实时获取、传输井下实时全景视频图像,利用无线全景摄像机和无线局域网的相关协议绑定矿工身份信息,并利用绑定的信息将矿工定位和跟踪服务整合到煤矿安全监控系统中;该系统能作为监控煤矿环境安全、煤矿生产安全、煤矿机车运输安全和人员安全的一种全新的解决方案,具有十分重要的应用价值和市场前景;测试结果表明设计的ODVS水平方向的成像范围为360°,垂直方向的成像范围为224°,其中仰角为22°、俯角为63°;压缩后的全景图像分辨率为640×480像素和320×240像素(可选),能够很好地实现煤矿安全的监控。展开更多
基金National Natural Science Foundations of China(Nos.60872073,6097501,and 51075068)the Doctoral Fund of Ministry of Education of China(No.20110092130004)the Research Foundation and Education Bureau of Anhui Province of China(No.KJ2009B137)
文摘Medium access control( MAC) protocol of underwater acoustic communication network is a key technology for underwater acoustic networks( UANs). Most of the MAC protocols for wireless terrestrial communication networks have been designed with negligible propagation delay. If it is deployed directly in an underwater environment,the UANs will perform inefficiently. In this paper,the characteristics of underwater acoustic channel are modeled and simulated by using the OPNET simulation tool,which are the speed of sound, propagation loss, and four sources for ambient noise: the turbulence,shipping,wind driven waves and thermal noise. The performance of pure Aloha( P-Aloha),carrier sense multiple access with collision avoidance( CSMA / CA) and multiple access collision avoidance for wireless local area network( MACAW) protocols in underwater acoustic channel environment are evaluated. The different performance of protocols in underwater environment is compared in the simulation.
文摘针对煤矿下复杂环境及其安全管理需求,提出一种基于WLAN(Wireless Local Area Network)的全景视觉煤矿安全监控系统,采用ODVS(Omni-Directional Vision Sensors)配合有线和无线通信方式传输图像、信息、指令和数据,实时获取、传输井下实时全景视频图像,利用无线全景摄像机和无线局域网的相关协议绑定矿工身份信息,并利用绑定的信息将矿工定位和跟踪服务整合到煤矿安全监控系统中;该系统能作为监控煤矿环境安全、煤矿生产安全、煤矿机车运输安全和人员安全的一种全新的解决方案,具有十分重要的应用价值和市场前景;测试结果表明设计的ODVS水平方向的成像范围为360°,垂直方向的成像范围为224°,其中仰角为22°、俯角为63°;压缩后的全景图像分辨率为640×480像素和320×240像素(可选),能够很好地实现煤矿安全的监控。
