System Support for Distributed Information Change Monitoring

该项目研究了在诸如因特网和万维网的大型分布式网络中监视信息变化的设计和实现问题。目标之一是开发高效且可扩展的策略、技术和系统支持，以分布式控制大量信息更改监视请求。需要解决的研究问题包括以下几个方面。哪些软件技术和工具能够提取、集成和查询半结构化或非结构化数据上的数据流？在存在数百万个信息更改监视请求的情况下，哪些分布式触发器和数据处理技术最具可伸缩性且效率最高？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？随着信息源的数量达到数百万，它们如何扩大规模？关键系统组件包括变化检测算法(例如，网页的树比较)、触发器和查询分组、索引和高速缓存以及并行处理。将通过互联网上的模拟和测量来实施和评估适当的组件。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。研究成果将有助于设计、实施和评估系统和中间件软件，以支持可伸缩和高效地处理分布式触发和查询，以及有效地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.