CAREER: NetTraveler: A Database Middleware System for Ubiquitous Data Access on Wide-Area Networks

在广域网上部署的下一波信息系统将以驻留在支持internet的手持设备、移动笔记本电脑和其他小型设备上的数据源为特征。这些主机将管理重要的数据集（例如，传感器读数、医疗信息、金融数据），并随着它们的所有者跨越地理区域而改变网络位置。这个项目的目标是NetTraveler的设计、实现和评估，NetTraveler是一个数据库中间件基础设施，用于定位、动态联合和集成驻留在移动设备和企业服务器上的数据源。NetTraveler的核心创新是它的软件抽象、协议和算法，使NetTraveler能够有效地在可能是移动主机的站点上运行查询。NetTraveler提供了一个上下文感知的查询处理框架，根据主机的性质来调度查询操作符，这在每个主机提交的动态配置文件中指定。NetTraveler通过缓存查询结果或保存在先前断开的源重新连接时恢复查询执行所需的最小状态信息的算法来防止由于间歇性连接而导致的查询处理工作的损失。就更广泛的影响而言，该项目将研究和教育活动结合起来，为西班牙裔研究生和本科生提供沉浸在数据库研究中的机会。新课程将在中间件系统和移动主机的应用程序开发中开发。这些活动的预期成果包括NetTraveler的源代码、课程材料、教程、研讨会和研究论文。这些活动的所有材料都可以从项目网站（http://www.ece.uprm.edu/~manuel/nettraveler/）免费获得。

The next wave of information systems to be deployed over Wide-Area Networks will feature data sources residing on Internet-enabled handheld devices, mobile laptops, and other small devices. These hosts will manage important data sets (e.g., sensor readings, medical information, financial data), and change network location as their owners move with them across geographical regions. The goal of this project is the design, implementation, and evaluation of NetTraveler, a database middleware infrastructure that locates, dynamically federates and integrates data sources residing on mobile devices and enterprise servers. The core innovations in NetTraveler are its software abstractions, protocols, and algorithms that enable NetTraveler to efficiently run queries over sites that might be mobile hosts. NetTraveler provides a context-aware query processing framework to schedule query operators based on the nature of hosts, as specified in a dynamic profile submitted by each host. NetTraveler prevents loss of query processing effort due to intermittent connectivity by means of algorithms that either cache query results, or save minimal state information necessary to resume query execution once a previously disconnected source reconnects again. Regarding broader impacts, this project combines research and educational activities to provide Hispanic graduate and undergraduate students at UPRM with the opportunity to become immerse in database research. New courses will be developed in middleware systems, and application development for mobile hosts. Expected outcomes of these activities include the source code for NetTraveler, course materials, tutorials, seminars, and research papers. All materials for these activities are freely available from the project Web site (http://www.ece.uprm.edu/~manuel/nettraveler/).