Quality-adaptice methods dor elastic real time applications

这项工作的广泛目标是开发新的系统和网络技术，以支持时间敏感的分布式应用程序，使用尽力而为的商品基础设施。这项工作的研究目标是相关的质量适应的一般主题，其动机是解决时间敏感的应用程序和最大努力的服务模式，仍然是唯一的选择提供给绝大多数互联网用户之间的冲突。我们的目标是探索如何应用上下文感知计算的原理来增强面向用户和社区的视频制作和分发过程。质量自适应的一般思想是构建系统，以便它们可以动态地调整其结果的质量，从而使用碰巧可用的资源来达到应用的基本时序要求（网络带宽、处理器周期、存储空间、显示区域等）。这种方法的动机是解决两个基本的障碍，可预测的时间：设备多样性和动态共享资源。从长远来看，这里提出的工作旨在实现“无处不在的媒体访问”的愿景，其中商品设备-可以预期是丰富的，非常多样化的，多媒体能力和网络能力-能够作为端点的连续媒体流，有效地和协调的方式，从而形成了广泛的新的分布式应用程序的基础。

The broad goal of this work is to develop new systems and networking techniques to support time-sensitive distributed applications, using a best-effort commodity infrastructure. The research objectives of this work are related by a general theme of quality adaptation, the motivation of which is to address the conflict between time-sensitive applications and the best effort service model that still remains the sole option available to the vast majority of Internet users. We also aim to explore how to apply principles of context-aware computing to enhance the process of user and community oriented video production and distribution.The general idea of quality adaptation is to structure systems so that they can dynamically adapt the quality of their results, in such a way as to attain the basic timing requirements of the application, using the resources that happen to be available (network bandwidth, processor cycles, storage space, display area, etc.). This approach is motivated to address two fundamental obstactles to predictable timing: device diversity and dynamic sharing of resources. In the long term, the work proposed here aims toward a vision of "ubiquitious media access", wherein commodity devices---which can be expected to be abundant, vastly diverse, multimedia-capable, and network capable---are able to act as endpoints for the streaming of continuous media, effectively and in a co-ordinated fashion, thereby forming the basis for a broad range of new distributed applications.