location tracking in a wireless sensor network by mobile agents and its data fusion strategies...
TRANSCRIPT
Location Tracking in a Wireless Sensor Network by Mobile Agents and Its
Data Fusion Strategies Yu-Chee Tseng, Sheng-Po Kuo, Hung-Wei Lee and Chi-Fu Huang
The Computer Journal 2004Special Focus-Mobile and pervasive computing Volume 47, Issue 4, July 2004: pp. 448-460
Bao-Hua Yang
Outline
Introduction Network Model and Problem Statement The Location Tracking Protocol Fusion and Delivery of Tracking Results Prototyping Experiences and Simulation
Results Conclusion
Introduction
Many issues remain to be resolved for success of sensor network Scalability
Sensor network comprises a large number of nodes How to manage resources and information is not easy
Stability Be installed in outdoor or hostile environments Protocols should be stable and fault-tolerant
Power-saving Energy conservation should be kept in mind in all cases
Introduction
GoalLocation tracking: to monitor the roaming path
of a moving object An object is detected
A mobile agent will be initiated to track the roaming path
The agent will choose the sensor closest to the object to stay
Network Model and Problem Statement
Network Model and Problem Statement---Assumption
In order to track objects’ location, the sensor should know: Aware of its physical location Aware of the neighbor physical location The capability of compute and communication Sensing scope: R = the side length of the triangles
Object Assume that sensors can distinguish one object from
another
Network Model and Problem Statement
Working area: A0
Backup area:A1,A2,A3
The Location Tracking Protocol--- Basic idea
Master
Slave2 Slave1
The Location Tracking Protocol--- Basic idea
MasterSlave2
Slave1
The Location Tracking Protocol--- Basic idea
MasterSlave2
Slave1
The Location Tracking Protocol--- Basic idea
Master
Slave2 Slave1
The Location Tracking Protocol--- Protocol detail
•Status: Idle
Bid_master(ID,sig)
The Location Tracking Protocol--- Protocol detail
The Location Tracking Protocol--- Protocol detail
The Location Tracking Protocol--- Protocol detail
The Location Tracking Protocol--- Protocol detail
The Location Tracking Protocol--- Protocol detail
The Location Tracking Protocol--- Protocol detail
S0 S2
S1
The Location Tracking Protocol--- Protocol detail
(1):Master will revoke all slaves and invite two new one
(2):Master revoke slave S1 and invite a new one
(3):Master migrate itself to a sensor with strongest receive signals and revoke all slaves
slaveslave
Master
(4)
(5)
(6)
The Location Tracking Protocol--- Protocol detail
The Location Tracking Protocol--- Protocol detail
S0 S2
S1
The Location Tracking Protocol--- Protocol detail
S0 S2
S1
The Location Tracking Protocol--- Extension to irregular network topologies
The election process does not need to be changesSensors can still bid for serving as a
master/slave based on their signal strengths Only the rules to migrate masters/slaves
need to be modified
The Location Tracking Protocol--- Extension to irregular network topologies
Using Voronoi graphs to find the master and slaves
(b)The Voronoi graphs after removing the master
(c)The Voronoi graphs after removing the master and the first slave
(a)The Voronoi graphs of all vertics
The Location Tracking Protocol--- Extension to irregular network topologies
Working and backup areas
Backup area
Working area
Fusion and Delivery of Tracking Results Non-Agent-Based (NAB) strategy
Each sensor works independently and forward its sensing results back to the gateway
Threshold-Based (TB) strategy
Si Si+1
G
(1)The amount of result < Threshold carry(2)The amount of result > Threshold forward
1
12
Fusion and Delivery of Tracking Results Distance-Based (DB) strategy
The distance from the agent’s current and next sensors to the gateway are considered
Fusion and Delivery of Tracking Results G
iff C1 < C2 : the master agent will carry the results with itOtherwise: the results will be sent back to the gateway
Si Si+1
Si decides to carry the tracking result with it:
Si decides to deliver its current tracking result to the gateway:
1
12
Ni=
Prototyping Experiences and Simulation Results Simulation environment
Sensing field: 10000m*10000m Distance between two neighboring sensors:80mGateway is located at the center of the networkObject moves at a constant speed: 1~3mControl packet, location information, packet head
er: 2 bytes
Prototyping Experiences and Simulation Results
Experimental environment: (a) Triangular sensor network(b) Square sensor network
Prototyping Experiences and Simulation Results
Prototyping Experiences and Simulation Results
Prototyping Experiences and Simulation Results
Prototyping Experiences and Simulation Results
Prototyping Experiences and Simulation Results
Conclusion
Proposed a location-tracking protocol for regular and irregular sensor network Reducing communication and sensing
overhead