David Rogers, Stu Andrzejewski,
Kelly Desmond, Brad Garrod
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Receiving correct data
Communicating across network nodes
accurately
Proper operation
EKG graphs
Insufficient Node Power
Environmental Factors
Malicious Nodes

Can destroy…
◦ Health/Lives
 Air Pollution
◦ Equipment
 Automobile
◦ Environment
 Forest Fire
Overall failing sensors can lead to
millions of dollars in damage!
1.
2.
3.
4.
Configure a sensor network
Collect metrics about the network
Create human/network interface
Analyze correlations between metrics and
node failure
5. Validate metrics and test for accuracy
1. Configure a sensor network
A. Define network topology
B. Identify vital components of sensor hardware
C. Select sensor network hardware
2. Collect metrics about the network
3. Create human/network interface
4. Analyze correlations between metrics and
node failure
5. Validate metrics for accuracy
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Star Topology
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◦ Cluster head controls data
communication between
nodes
• Advantages
• Disadvantages
•
•
•
•
Better
performance
Benefits from
centralization
Isolation of
nodes
Simple
•
•
•
Centralization
dependency
Expensive
Central hub
failure =
network
failure
Mesh Topology
◦ Nodes communicate directly
to other nodes without the
need of a cluster head
• Advantages
•
•
•
Self- healing
Less traffic load
Isolation of
node faults
• Disadvantages
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•
•
Complexity
Installation
Price

What kinds of information from the sensor would
be useful to understand how well they are
functioning?
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Battery life
Current draw
RF transmission power
Received signal strength
Processor load
Memory utilization
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Powercast P2110-EVAL

Features
Low-power
Battery-free (RF Power)
Pre-loaded, custom firmware
Temperature, Humidity, and Light
Sensors
◦ External Sensor Port
◦ RSSI Calculation
◦ USB interface for power and data
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
SunSPOT

Features
◦ Embedded Development Platform
◦ Extremely flexible hardware and
software package
◦ Easy to program - Java top to bottom
◦ Connected – Wireless Communication
◦ Mobile & Secure
◦ Built in Lithium Ion battery charged
through USB
◦ Able to sense and affect surroundings
◦ Built-in high grade ECC public key
cryptography
1. Configure a sensor network
2. Collect metrics about the network
A. What to monitor?
3. Create human/network interface
4. Analyze correlations between metrics and
node failure
5. Validate metrics for accuracy
2A. What to monitor?

External
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Humidity
Temperature
Light
Sound
Motion
Pressure
Vibration
Electrical Fields
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Internal
Current Draw
Battery Life
Voltage Reported
RF Transmission
Received Signal
Strength
◦ Channel Availability
◦ Processor Load
◦ Memory Utilization
(RAM)
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1. Configure a sensor network
2. Collect metrics about the network
3. Create human/network interface
A. Identify ideal communication protocol
B. Create graphical user interface
4. Analyze correlations between metrics and
node failure
5. Validate metrics for accuracy


Must be able to communicate with sensors
remotely
IEEE 802.15.4
◦ Includes ZigBee, Bluetooth, Wifi
◦ Uses CSMA/CA for secure communications
 Nodes only transmit when the channel is idle
◦ Devices also include power management functions
such as link quality and energy detection.

Create user-friendly display
◦ Handles all incoming data packets from sensor
nodes behind the scenes
 The data will be displayed in a way for easy evaluation
of the sensor data stream and network health
◦ Alerts the operator when failures have occurred or
are occurring
1.
2.
3.
4.
Configure a sensor network
Collect metrics about the network
Create human/network interface
Analyze correlations between metrics and
node failure
5. Validate metrics for accuracy


Determine the most important metrics that
identify node failure
Algorithms for detecting malfunctioning nodes
◦ Majority Voting
◦ Thresholding
◦ Weighted average

Understanding associations between multiple
metrics
◦ Attempting to measure current draw while the
sensor is transmitting back to the cluster head
1.
2.
3.
4.
Configure a sensor network
Collect metrics about the network
Create human/network interface
Analyze correlations between metrics and
node failure
5. Validate metrics for accuracy

Design a test plan to ensure a high quality
health diagnostic
◦ Series of controlled experiments

Statistically validate chosen algorithms
◦ Reduce false positives and false negatives


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Monitoring sensor health is vital for proper
function of a wireless sensor network
Many external and internal factors attribute
to sensor node failure
By designing algorithms and a test plan to
systematically validate failures, important
metrics relating to the health of a wireless
sensor network can be determined