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Overview and applications
Vinod Kulathumani
West Virginia University
2
Outline
• Vision for sensor actuator networks
Networked embedded systems
Enabling technology
Application areas
• Sensing-only systems
Monitoring related applications
Application examples
Challenges and design space
• Sensing + actuation
Examples
Challenges and design space
• ExScal, an example surveillance application
3
Embedded systems
• Found in variety of devices
Aircraft, radar systems, nuclear and chemical plants
Vehicles, TVs, camcorders, elevators
> 90% of CPUs used for embedded devices
4
Networked embedded systemsCurrently
• Embedded processors - part of a larger system
• Application known apriori
Little flexibility in programming
What if?
• embedded processors were connected – preferably wireless?
• there was greater flexibility in programming ?
• sensing and actuation capabilities were included ?
5
The Vision for WSANs
• Combine wireless networks with sensing / actuation
Ubiquitous computing / pervasive computing
• Fine-grained monitoring and control of environment
• Network and interact with billions of embedded computers
Reasons
• Wireless communication - no need for infrastructure setup
• Drop and play
• Nodes are built using off-the-shelf cheap components
• Feasible to deploy nodes densely
6
New Class of Computing
year
log
(p
eo
ple
pe
r c
om
pu
ter)
streaming informationto/from physical world
Number CrunchingData Storage
productivityinteractive
Mainframe
Minicomputer
Workstation
PC
Laptop
PDA
Slide courtesy: Murat Demirbas
7
Opinions
Tiny computers that constantly monitor ecosystems, buildings, and even human bodies could turn science on its head.
- Nature, March 2006
The use of sensornets throughout society could well dwarf previous milestones in information revolution.
- National Research Council report, 2001
Reinventing computer science
- David Tennenhouse, Intel, 2000
8
Enabling technology
• Powerful microprocessors
Small form factor
Low energy consumption
• Micro-sensors (MEMS, Materials, Circuits)
acceleration, vibration, gyroscope, tilt, motion magnetic, heat, pressure, temp, light, moisture, humidity, barometric
chemical (CO, CO2, radon), biological, micro-radar
actuators (mirrors, motors, smart surfaces, micro-robots)
• Communication
short range, low bit-rate, CMOS radios
9
A typical sensor node
• Telosb (2007)
8 MHz MSP430 processor
10kB RAM
250 Kbps data rate
Integrated temperature, humidity, light sensors
• Others
10
Application areas for WSANs
• Science
Environmental and habitat monitoring
Oceanography, seismology, water management, …
• Engineering
Precision agriculture
Industrial automation
Control systems, …
• Daily life
Detecting emergencies and alerting, disaster recovery
Health care
Traffic management and many more
11
Sensing only systems
• Popular as wireless sensor networks
• Useful for monitoring based applications
• Large scale networks of embedded sensors
Connected to a remote base station
Self-configuring
Typically resource constrained (Why?)
12
Block diagram of a sensor node
Substitute any sensing / actuating modality
Actuator(Buzzer)
Processor
Application
NetworkInterface
PROCESSINGSUB-SYSTEM
COMMUNICATIONSUB-SYSTEM
SENSINGSUB-SYSTEM
POWER MGMT.SUB-SYSTEM
ACTUATIONSUB-SYSTEM
SECURITYSUB-SYSTEMSensor
(Light)
13
Application category – Monitoring type
Environmental monitoring
Perimeter security
Infrastructure monitoringBody sensor networks
Object tracking
Camera sensor networks
14
Emerging applications
• Combination of sensors with mobile devices
Social networking
Participatory urban sensing
• Assisted living – health monitoring
• Vehicular networks with variety of sensors
15
Specific examples
• Detect and track intruders in a secure area
• Detect chemical or biological attacks
• Detect building fires and set up evacuation routes
• Monitoring dangerous plants
• Monitoring social behavior of animals in farms and natural habitats
• Monitoring salinity of water
• Monitoring cracks in bridges
• Tracking dangerous goods
• Shooter Localization
• Epilepsy monitoring and suppression
• Camera networks for urban surveillance
• Monitoring traffic on a highway
16
Challenges in sensor networks
• Energy constraint
• Unreliable communication
• Unreliable sensors
• Ad hoc deployment
• Large scale networks
• Distributed execution
• Ease of use
: Nodes are battery powered
: Radio broadcast, limited bandwidth, bursty traffic
: False positives
: Pre-configuration inapplicable
: Algorithms should scale well
: Difficult to debug & get it right
: All Scientists not programmers
17
Sensing + actuation systems
• Not simply monitoring events, objects
Combined with actuation
• Traditional control applications
Decouple information availability
Control assumes information is instantaneously available
• What if information is transmitted over a sensor network?
Losses, delays in information
• New tools needed for programming, reasoning about such systems
• Building blocks for Cyber-physical systems - recent buzzword!
18
Sensing + actuation systems
• Not simply monitoring events, objects
Combined with actuation
• Traditional control applications
Decouple information availability
Control assumes information is instantaneously available
• What if information is transmitted over a sensor network?
Losses, delays in information
• New tools needed for programming, reasoning about such systems
• Building blocks for Cyber-physical systems - recent buzzword!
Note
Applying control theory for network systems – has existed before (example: TCP congestion)
This is control systems designed on top of networks
19
Example sensor actuator networks
• Robotic systems
Self-configuring structures
Robotic surgery
Self-configuring table
http://www.youtube.com/ssrlab0/#p/u/24/5uR34U1qc-Q
• Autonomic vehicular platoons
Use in UAV swarms
Autonomous driving – Google Car!
• Distributed vibration control
• Distributed illumination control, irrigation, process control
• Smart power grid
20
We saw all these challenges for sensor networks
• Energy constraint
• Unreliable communication
• Unreliable sensors
• Ad hoc deployment
• Large scale networks
• Distributed execution
• Ease of use
: Nodes are battery powered
: Wireless, limited bandwidth, bursty traffic
: False positives, negatives
: Pre-configuration inapplicable
: Algorithms should scale well
: Difficult to debug & get it right
: All Scientists not programmers
21
Add to these ....
• Energy constraint
• Unreliable communication
• Unreliable sensors
• Ad hoc deployment
• Large scale networks
• Distributed execution
• Ease of use
: Nodes are battery powered
: Wireless, limited bandwidth, bursty traffic
: False positives, negatives
: Pre-configuration inapplicable
: Algorithms should scale well
: Difficult to debug & get it right
: All Scientists not programmers
…. A control application that sits on top
Requires information guarantees from network below!
22
Relation to CPS
“Cyber-physical systems are physical, biological, and engineered systems whose operations are integrated, monitored, and/or controlled by a computational core.
Components are networked at every scale. Computing is deeply embedded into every physical component, possibly even into materials.
The computational core is an embedded system, usually demands real-time response, and is most often distributed.
The behavior of a cyber-physical system is a fully-integrated hybridization of computational (logical), physical, and human action.”
- National Science Foundation
23
Characteristics of CPS
• Cyber capability in every physical component
• Interaction at large scales with wired or wireless networks
• Dynamically re-organizing
• Novel computational substrates (bio / nano)
• Tight integration of computation, communication and control
High degree of automation
Operation must be dependable and certified
Sensor nets + control + distributed computing + real-time systems
24
Example: Automotive Telematics
• Intra-vehicular sensing and control Engine control, Break system, Airbag deployment system, windshield
wiper, Door locks, Entertainment system
• V2V networks Cars are sensors and actuators
Vehicular safety
Autonomous navigation
• Future Transportation Systems Incorporate both single person and mass transportation vehicles, air and
ground transportations.
achieve efficiency, safety, stability using real-time control and optimization.
25
Example: Health Care and Medicine
• Electronic Patient Records
Records accessible anywhere, any time
• Home care: monitoring and control
Pulse oximeters, blood glucose monitors, infusion pumps, accelerometers, …
• Operating Room of the Future
Closed loop monitoring and control; multiple treatment stations, plug and play devices; robotic microsurgery
System coordination challenge
• Progress in bioinformatics: gene, protein expression, systems biology, disease dynamics, control mechanisms
26
Example: Electric Power Grid
• Current picture Equipment protection devices trip locally, reactively
Cascading failure
• Better future? Real-time cooperative control of protection devices
Self-healing, aggregate islands of stable bulk power
Green technologies
Coordinate distributed and dynamically interacting participants
27
Assignment 1
• Choose a WSAN application paper and prepare a report and ppt
Prepare a 2 page report
11 point font
Latex typesetting preferred
Conference style formatting
Prepare list of references
Text in your own words State system requirements and challenges
List enabling technologies
Discuss how wireless networking of embedded devices play a role
Discuss scalability and robustness of solution
Discuss improvements and extensions
State one new application of your choice for WSNs
28
Assignment 1
• Samba: A Smartphone-Based Robot System for Energy-Efficient Aquatic Environment Monitoring [ipsn 2015]
• LookUp: Enabling Pedestrian Safety Services via shoe Sensing [mobisys 2015]
• Contactless sleep apnea detection using smartphones [mobisys 2015]
• AccelWord: Energy Efficient Hotword Detection through Accelerometer [Mobisys 2015
29
Assignment 1
• A System for Fine-Grained Remote Monitoring, Control and Pre-Paid Electrical Service in Rural Microgrids (CMU, IPSN 2014)
• Aquatic Debris Monitoring Using Smartphone-Based Robotic Sensors (MSU, IPSN 2014)
• Airplanes Aloft as a Sensor Network for Wind Forecasting (Microsoft Research, IPSN 2014)
• One Meter to Find Them All - Water Network Leak Localization Using a Single Flow Meter (Penn state, IPSN 2014)
30
Assignment 1
• Magneto-Inductive NEtworked Rescue System (MINERS): Taking sensor networks underground(Oxford, IPSN 2012)
• Sensing Through the Continent: Towards Monitoring Migratory Birds using Cellular Sensor Networks (Nebraska, IPSN 2012)
• Non-invasive Respiration Rate Monitoring Using a Single COTS TX-RX Pair (Aalto university, IPSN 2014)
• Using wearable inertial sensors for posture and position tracking in unconstrained environments through learned translation manifolds (Edinburgh, IPSN 2013)
31
Other previous applications
SLEWS: A Sensorbased Landslide Early Warning System
Power grid monitoring
Embedded systems for energy-efficient buildings (eDIANA)
Water quality monitoring
Sensor networks for UV radiation control
Precision agriculture and Agricultural applications
Indoor environmental monitoring systems
Damage detection in civil structures
Participatory urban sensing
32
Other previous applications
Micro-strain sensor network for monitoring shuttle launch
Smart room using camera networks
Active visitor guidance system
Analysis of a habitat monitoring application
Smart-tag based data dissemination
Meteorology and Hydrology in Yosemite
Continuous medical monitoring
ZebraNet
Virtual fences
33
Other previous applications
SenseWeb
CarTel
Assisted Living
Wearable wireless body area networks (Health care)
Adaptive house
House_n project
Responsive Environments
Counter-sniper system
Self-healing land mines
34
Other previous applications
• Take a look at Libelium Top 50 applications
These are some of the potential application areas for sensor actuator networks: mostly non-military
http://www.libelium.com/top_50_iot_sensor_applications_ranking/
• AN APLICATION THAT I JUST SAW TODAY
SMART DIAPERS!
• THE IOT SPACE IS BOOMING
LOTS OF APPLICATIONS
CREATIVITY AND IMAGINATION IS THE LIMIT
35
Put tripwires anywhere—in deserts, other areas where physical
terrain does not constrain troop or vehicle movement—to
detect, classify & track intruders [Computer Networks 2004,
ALineInTheSand webpage, ExScal webpage]
Project ExScal: Concept of operation
37
Application design choice
• One large powerful sensor vs many distributed sensors
• Distribution favours
Robustness
Overall coverage
Overall cost
• Focus is on distributed computing and networking
38
ExScal summary
• Application has tight constraints of event detection scenarios: long life but still low latency, high accuracy over large perimeter area
• Demonstrated in December 2004 in Florida
• Deployment area: 1,260m x 288m
• ~1000 XSMs, the largest WSN
• ~200 XSSs, the largest 802.11b ad hoc network
39
One of ExScal sensors - PIR
PIR is a differential sensor: detects target as it crosses the “beams”
produced by the optic
40
PIR signal: Frequency
Human at 10 m Car at 25m
Energy content for these two targets is in low frequency band
41
Pir target detector
Person at 12 m
Bandpass: [0.4- 2 Hz]
[0-0.3 Hz]
Bandpass: [2- 4 Hz]
SUV at 25 m
42
A distributed classification approach
Assume a dense WSN
– Concept: each target type has unique influence field
– Multiple sensors which detect target coordinate,
potentially each with multiple sensing modalities
– Classification is via reliable estimation of influence field size
[Computer Networks 2004]
43
Further reading
The Computer for 21st Century
Next century challenges: mobile networking for Smart Dust
Connecting the physical world with pervasive networks
D. Tennenhouse, Proactive computing
Energy and performance considerations for smart dust
Interesting Links on Sensor Networks
www.wsnblog.com
44
Further reading
Some good advice for graduate students:
• Edsger Dijkstra, The Three Golden Rules for Successful Scientific Research
• Edsger Dijkstra, To a New Member of the Tuesday Afternoon Club
• Jim Kurose, Ten Pieces of Advice I Wish My PhD Advisor Had Given Me
• Andre DeHon, Advice for Students Starting into Research
• S. Keshav, How to Read a Paper
• Philip W. L. Fong, How to Read a CS Research Paper?
• William Strunk Jr., E. B. White, The Elements of Style. (Recommended book on writing)