ITR: Keyword Searching in Loosely Coupled Distributed Systems

松散耦合的分布式系统是指节点在没有集中控制的情况下可以高速率地加入、离开或发生故障，并且网络连接或拓扑可能非常不稳定。例子包括自组织覆盖网络、移动自组织网络(MANET)和传感器网络。该提案旨在解决在这些动态系统中支持关键字搜索的问题。关键字搜索对于覆盖网络中的信息检索和传感器网络的栖息地监测等高层分布式服务是一种非常有效的工具，该方案旨在构建一个分布式关键字搜索框架，以达到系统可伸缩性、搜索速度、内容陈旧和搜索质量的理想水平。提议的设计的核心是一种称为摘要索引的分布式数据结构，它为更远的内容维护逐渐不那么准确的搜索索引，以实现可伸缩性。该项目包含三个主要内容：1.为松散耦合的分布式系统创建一个健壮的基于“摘要索引”的关键字搜索框架；2.研究各种系统组件的设计并研究性能指标之间的权衡；3.结合系统集成和应用研究。

Loosely coupled distributed systems are those in which nodes can join, leave, or fail at high rates without centralized control and network connections or topology can be highly unstable. Examples include self-organizing overlay networks, mobile ad hoc networks (MANET), and sensor networks. This proposal seeks to address issues in supporting key searching in these dynamic systems. Keyword searching is an extremely effective utility for many higher-level distributed services, such as information retrieval in overlay networks and habitat monitoring for sensor networks.This proposal seeks to build a distributed keyword searching framework that achieves a desirable level of system scalability, search speed, content staleness, and quality of search. The heart of the proposed design is a distributed data structure called a summary index, which maintains gradually less accurate search index for content farther away to achieve scalability. This project contains three main thrusts: 1. creating a robust "summary index"-based keyword searching framework for loosely coupled distributed systems, 2. examining the design of various system components and studying the tradeoffs among performance metrics, and 3. incorporating system integration and application studies.