1. FAULT TOLERANT TECHNIQUES FOR WIRELESS AD HOC SENSOR NETWORKS
RAM MOHAN BOPPUDI
EE 585 :CASE STUDY 2
ram mohan
university of kentucky

2. WIRELESS AD HOC SENSOR NETWORK
ram mohan
university of kentucky

3. university of kentucky
INTRODUCTION
A wireless ad hoc sensor network.
Some examples of wireless ad hoc sensor networks are the following:
Military sensor networks .  
Sensor networks to detect and characterize Chemical, Biological, Radiological, Nuclear, and Explosive (CBRNE) attacks and material.  
Sensor networks to detect and monitor environmental changes.  
Wireless traffic sensor networks.  
Wireless surveillance sensor networks.  
Wireless parking lot sensor networks.
ram mohan
university of kentucky

4. university of kentucky
INTRODUCTION(CONT..)
Wireless ad hoc sensor network requirements include the
following:
Large number of (mostly stationary) sensors.  
Low energy use.  
Network self-organization.  
Collaborative signal processing.  
Querying ability.
ram mohan
university of kentucky

5. university of kentucky
GOALS
The basic goals of a wireless ad hoc sensor network
generally depend upon the application, but the following
tasks are common to many networks:
Determine the value of some parameter at a given location.  
Detect the occurrence of events of interest and estimate parameters of the detected event or events .  
Classify a detected object .  
Track an object.
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university of kentucky

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SENSOR
We focus our attention on how to back-up one type of sensor with another.
There are two main reasons for this decision. The first is that technology trends indicate that sensing has by far the highest fault rates.
The second is that there is a wide consensus that multi-modal sensor fusion is the key for successful and widespread use of embedded sensor networks.
Two fault models:
-sensors that produce binary outputs.
-sensors with multilevel digital outputs.
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university of kentucky

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SENSOR NODE
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university of kentucky

8. MULTIMODAL SENSOR FUSION
Problem of multi modal sensor fusion for digital binary sensors.
Sensor resource allocation and assignment problems ask to identify the minimal number of sensors.
ram mohan
university of kentucky

9. MULTI MODAL SENSOR NETWORK
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university of kentucky

10. FAULT TOLERANT SOLUTION
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university of kentucky

11. TRADITIONAL VS HETEROGENEOUS
Traditional methods – double redundancy.
- triple redundancy.
Importance of heterogeneous over traditional.
-low energy.
-cost.
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university of kentucky

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EXPERIMENTAL RESULTS
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university of kentucky

13. ALGORITHMIC ENGINES TO SRA PROBLEM
Two different techniques to solve the allocation problem:
ILP-based and
Simulated annealing based.
-move.
-objective function.
-cooling schedule.
-stop ping criteria.
ram mohan
university of kentucky

14. FAULT TOLERANCE IN MULTIMODAL SENSORY SYSTEMS
A number of sensors, some of them different with modalities.
The goal is to extract as accurately as possible the information requested by a user from noisy measurements.
Four types of sensors in following example for introduced approach.
ram mohan
university of kentucky

15. university of kentucky
ram mohan
university of kentucky

16. MULTI MODAL SENSOR SYSTEMS
ram mohan
university of kentucky

17. FAULT TOLERANCE IN MULTIMODAL SENSOR SYSTEMS
ram mohan
university of kentucky

18. MULTIMODAL SENSOR SYSTEMS
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university of kentucky

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CONCLUSION
New approach to multimodal sensor fusion.
Key idea is to use one type of sensor to back up sensors of different types by exploiting flexibility during multimodal sensor data fusion.
Formulated the problem for 2 diff. type of sensors binary and multi-level sensors.
Developed algorithms to solve them .
ram mohan
university of kentucky

20. university of kentucky
REFERENCES
Fault tolerance techniques for wireless ad hoc sensor networks by
Farinaz Kounshafar
Miodrag Potkonjak
Alberto Vincentilli.
ram mohan
university of kentucky