130 likes | 227 Views
ECET 581. Wireless Sensor Networks Sensor Network Data Management December 5, 2006 Fall 2006 http://www.etcs.ipfw.edu/~lin References:
E N D
ECET 581 Wireless Sensor Networks Sensor Network Data Management December 5, 2006 Fall 2006 http://www.etcs.ipfw.edu/~lin References: **Ch 6 Sensor Network Databases of the book: "Wireless Sensor Networks - An Information Processing Approach," by Feng Zhao and Leonidas Guibas, from Morgan Kaufmann/Elsevier inc, 2004 ** Ch 10 Data Management of the book: Principles of Embedded Networked System Design, by Gregory and William Kaiser, from Cambridge University Press **TMote Sky Web site: www.moteiv.com WSN Mote- MCU & Sensor Hardware
Sensor Networks Data Management • Traditional Database Management System • Sensor Data & Database • Sensor data organization • Distributed storage • Query & access • Wireless Sensor Database Design • Data Flow in Sensor Networks • High-level Reasoning WSN Mote- MCU & Sensor Hardware
Traditional Database Management System – an overview • Layered Architecture • Database • DBMS (Database Management System) • Communication Network • Client WSN Mote- MCU & Sensor Hardware
Traditional Database Management System – an overview • Database Schema – the structure and constraints of the data format defined through Data Definition Language (DDL) • Table • Rows - record tuples • Column – data attributes • DDL Compiler • Translates these definitions into Metadata • Metadata – a data structure describing the structure of database and constraints WSN Mote- MCU & Sensor Hardware
Traditional Database Management System – an overview • Transactions - a sequence of operations • Retrieving data • Database updating • Producing new tables • ACID Properties • Atomicity – all of the transaction takes place or nothing changes in the DB • Consistency – correctness (from begin to end) • Isolation – the transaction is concealed from other transactions until it commits • Durability – update effected by a transaction survive until affected by other transactions WSN Mote- MCU & Sensor Hardware
Traditional Database Management System – an overview • Query • Query Language – SQL (Structured Query Language) • Join, group-by, sort, scan • Query processor • Execution engine • Data storage • Geographically distributed at various locations • Robust to failure • Web-based access, remote access WSN Mote- MCU & Sensor Hardware
Sensor Data & Database • Data Info of Sensor Network • Time-stamped measurements of physical phenomena • Heat, sound, light, pressure, motion, etc • Abstract data representation • Detection, classification, tracking, etc • Sensor Description: location, types, etc • Database? • Traditional DBMS system • DB within the network WSN Mote- MCU & Sensor Hardware
Sensor Data & Database • Challenges • The system is highly volatile • Relational data tables are not static – new data is continuously being sensed • High energy cost in communication – encourage in network query • Long delay, need to continuously monitor the rates and availability of data • Maintain high-level statistical summaries: Limited storage on node and high communication cost • Sensor queries: queries from others, and self generated queries • Metrics of performance WSN Mote- MCU & Sensor Hardware
Distributed Database – Wireless Sensor Network • A set of database sites, each is a complete database system • Local DB – store frequently used data to minimize long-distance retrieval of large quantities of data • Fault tolerant • Primary copy, Secondary copies • Data object naming: • Creator ID • Creator Site ID • Local name • Birth site ID WSN Mote- MCU & Sensor Hardware
Data Flow in Sensor Networks • Data Management • Queries should direct • collection, storage, and transport of data and geographical and temporal scope • Signal processing, aggregation, and routing strategies • Must still consider • Concurrency • Integrity • Security • Efficiency WSN Mote- MCU & Sensor Hardware
Data Flow in Sensor Networks • Dealing with the infinite • Probabilistic data collection • Sensor networks as data compression engine • Interest diffusion • Adaptive data collection • Standards vs. custom design WSN Mote- MCU & Sensor Hardware
TinyDB Features • Metadata management • High-level queries: SQL like • Network topology • Tracking neighbors, and maintaining routing tables to determine how to deliver data efficiently • Multiple queries • diff sample rate and access diff sensors • Incremental deployment using query sharing WSN Mote- MCU & Sensor Hardware
High-Level Reasoning • Data Mining • Logic: if, then, else, not, therefore • Bayesian Networks – Belief networks • Language • Prolog WSN Mote- MCU & Sensor Hardware