tailieunhanh - A Database in Every Sensor

This paper describes the compilation of the first truly comprehensive historical public debt database (HPDD) covering gross government debt-to-GDP ratios for nearly the entire country membership of the IMF and spanning a long time period. The HPDD covers 174 countries and starts from 1880 for most G-7 countries and a few other advanced and emerging economies, and from 1920 for additional advanced and emerging economies. 2 For low-income countries (LICs), data coverage generally starts in 1970. The HPDD was compiled by bringing together a number of other databases of individual researchers or institutional bodies, as well as information from official government. | A Database in Every Sensor Nicolas Tsiftes Swedish Institute of Computer Science Box 1263 SE-16429 Kista Sweden nvt@ Adam Dunkels Swedish Institute of Computer Science Box 1263 SE-16429 Kista Sweden adam@ Abstract We make the case for a sensor network model in which each mote stores sensor data locally and provides a database query interface to the data. Unlike TinyDB and Cougar in which a sink node provides a database-like front end for filtering the current sensor values from a data collection network we propose that each sensor device should run its own database system. We present Antelope a database management system for resource-constrained sensors. Antelope provides a dynamic database system that enables run-time creation and deletion of databases and indexes. Antelope uses energy-efficient indexing techniques that significantly improve the performance of queries. The energy cost of a query that selects 100 tuples is less than the cost of a single packet transmission. Moving forward we believe that database techniques will be increasingly important in many emerging applications. Categories and Subject Descriptors Computer-Communication Networks Network Architecture and Design Wireless communication Database Management Systems General Terms Design Experimentation Measurement Performance Keywords Antelope Database Energy Efficiency Sensor Network 1 Introduction Over the last years low-power flash memory has both rapidly decreased in cost and rapidly increased in storage capacity. For sensor nodes today s flash memories can for most practical purposes be considered infinite nodes will run out of battery before running out of storage space. We argue that this opens for a new sensor network model where nodes store their data in a local flash storage and provide Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for .