System Support for Distributed Information Change Monitoring

该项目调查了在诸如因特网和万维网等大型分布式网络中监测信息变化的设计和实施问题。目标之一是为分布式控制大量信息更改监视请求开发高效且可伸缩的策略、技术和系统支持。要解决的研究问题包括以下内容。哪些软件技术和工具能够在半结构化或非结构化数据上提取、集成和查询数据流？在存在数百万个信息更改监视请求的情况下，哪种分布式触发器和数据处理技术是最具可伸缩性且最有效的？更改监控器如何适应运行时环境（如Internet）中广泛的系统参数变化？当信息源的数量达到数百万时，它们如何扩大规模？关键的系统组件包括变更检测算法（例如，网页的树比较），触发和查询分组，索引和缓存，以及并行处理。将通过因特网上的模拟和测量来实现和评估适当的组件。这些实验将强调互联网规模的信息变化监测系统的效率和可扩展性。研究结果将有助于系统和中间件软件的工程、实现和评估，以支持分布式触发器和查询的可扩展和有效处理，以及有效检测和通知信息变化。

The project investigates the design and implementation issues in the mointoring of information changes in large distributed networks such as the Internet and World Wide Web. One of the objectives is to develop efficient and scalable strategies, techniques, and systems support for distributed control of large numbers of information change monitoring requests. Research questions to be addressed include the following. What software techniques and tools are able to extract, integrate, and query streams of data over semi-structured or unstructured data? Which distributed trigger and data processing techniques are most scalable and yet efficient in the presence of millions of information change monitoring requests? How do change monitors adapt to wide system parameter variations in runtime environments such as the Internet? How do they scale up as the number of information sources reach millions? Critical system components include change detection algorithms (e.g., tree comparison for web pages), trigger and query grouping, indexing, and caching, as well as parallel processing. Appropriate components will be implemented and evaluated through simulation and measurements on the Internet. These experiments will emphasize the efficiency and scalability of Internet-scale information change monitoring systems. The research results will aid in the engineering, implementation and evaluation of systems and middleware software support for scalable and efficient processing of distributed triggers and queries, as well as effective detection and notification of information changes.