GLUE Project: A Geo-cache based Mobile Sensor Network System Bin - PowerPoint PPT Presentation

GLUE Project: A Geo-cache based Mobile Sensor Network System Bin Zan,Tingting Sun, Marco Gruteser, Yanyong Zhang WINLAB, Rutgers University {zanb,tsun,gruteser,yyzhang} @winlab.rutgers.edu 1

Mobile Sensor Networks � Technology trends � Increasing integration of sensors into mobile platforms � Accurate localization � Large storage � Applications � accident analysis and avoidance � dynamic noise pollution mapping through cell phone � pothole detection 2

Pothole Detection Example � Basic centralized approach: Transmit all data to external server immediately � Pro: complete information available at the server � Con: will soon saturate server capacity 3

Pothole Detection Example � Basic distributed approach: Store locally and retrieved by server later � Pro: no servers storage required � Con: high retrieval overhead 4

Challenge in Mobile Sensor Networks • How do we efficiently manage mobile sensor data for applications that need to access information from multiple nodes? 5

Key idea: tie data to the location Car 1: Here might be a pothole Car 4: Here might be a pothole Car 8: Here might be a pothole … 4 8 1 6

7 Query The Geo-Cache Concept

The Geo-Cache entries and I-page • Geo-cache page is the basic storage unit • Geo-cache page is bound to “Anchor Location” A • Each entry is a 4- attribute tuple • I-page contains the latest entries about a location and is kept around the location • Older entries can be accessed through chaining 8

Miss something?… How do the moving nodes hand off the Geo-Cache page among themselves? Answer: the anchoring protocol 9

Anchoring Protocol: Relay Relay Geo-cache Mode 10

Anchoring Protocol: Boomerang Boomerang Geo-cache Mode 11

More about anchoring protocol •Switching •high geo-cache coverage (relay) •short geo-cache delay (relay) •low communication overhead (boomerang) •low node density (boomerang) •Reliability •Energy Efficiency … Achieve reliability in boomerang mode 12

Preliminary Evaluation mean message per car mean message per car Broadcast Relay Relay Boomerang mean inter-car distance detection probability % � NS-2 simulation, with a 70-km two-lane road • ns2 � Pothole in the middle of the road � Each data point averaged over 1000 situations � Average speed 30m/s, and radio range 100m 13

Implementation In-Car Applications In-Car Sensor In-Car Sensor Sensor Event Event Event Event Detection Aggregation Event Event Detection Camera Aggregation Module Module Detection Aggregation Module Module Module Module Other Other Sensor Other Sensor Sensor Glue Subsystem GPS Relay Mode Boomerang I-page Mode Radio Storage 14

15 Data Collection

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Summary � Propose a distributed sensing and monitoring system for highly mobile vehicular networks named GLUE •Geo-cache •Anchoring protocol � The system is relying on inter-vehicle communication to exchange sensed and aggregated information. � The Geo-cache abstraction allows nodes to specify a geographic location to store information. 17

18 Questions?