ECET 581

1
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

2
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

3
Traditional Database Management System an
overview

• Layered Architecture
• Database
• DBMS (Database Management System)
• Communication Network
• Client

4
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

5
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

6
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

7
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

8
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

9
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

10
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

11
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

12
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

13
High-Level Reasoning

• Data Mining
• Logic if, then, else, not, therefore
• Bayesian Networks Belief networks
• Language
• Prolog