摘要
从BitTorrent协议算法在遥感影像流式传输中的局限性入手,研究BitTorrent结构中影像流式传输的实现机制,并提出一种基于BitTorrent的影像流式传输模型。模型在利用追踪服务器进行资源定位的基础上,使用适合影像流传输的影像瓦片动态下载队列机制,并对瓦片块选择下载算法进行改进。通过模拟试验测试表明,模型在影像瓦片块选择算法参数K取0.8时性能最佳,在大量用户并发访问场景中具有良好的稳定性。此外,模型在控制网络平衡性方面也较同类方式有所改进。
The limitations of the traditional BitTorrent protocol in providing spatial image streaming services are identified.The mechanism which support spatial image streaming in BitTorrent is described.A spatial image streaming model based on BitTorrent is also proposed.The model makes use of tracker in locating resources.Further,dynamic image tiles downloading queue which optimize image transmission is adopted in our model.Considering that the piece selection algorithms of the traditional BitTorrent protocol have many limitations in supporting image streaming,our approach gives image tiles different priorities firstly before they＇re requested.Then a parameter K to strike the balance between high priority tiles and low priority image tiles is used.Experimental results show that the model has the best performance when parameter K equals to 0.8 and maintains stable in the scenario of flash crowd.Also,the model gets improvement in controlling the workload balance of the network.
出处
《测绘学报》
EI
CSCD
北大核心
2013年第2期225-232,共8页
Acta Geodaetica et Cartographica Sinica
基金
水利部公益性行业科研专项经费(201001046)
