Real Problems.Real Research?

Vicraj (Vic) Thomasvic.thomas@honeywell.com

22 March 2007

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Background

• Staff Scientist at Honeywell Labs, Minneapolis• Research Interests

- Distributed embedded systems

- Sensor networks

- Wireless networks for flight-essential aircraft systems

- Dependable system design

• Recent sensor networking related projects- Wireless sensor networks for vehicle health management

- Wireless sensors for avionics systems

- Networked MEMS optical sensors for battlefield situation awareness

- Quality of information from sensor networks

I’m not young enough to know everything— Oscar Wilde

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Observations

• Fielding a sensor network is non-trivial …• …But not for reasons you’d expect if you delve into

the research out there• It’s the mundane realities of life that get you

Practical wisdom is only to be learned in theschool of experience

— Samuel Smiles

Real Problems

True Stories from Sensor Network Deployments

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1. The Grass Grows Fast in Florida

• System: Sensor network to detect an event• Our focus

- Minimize false positives and negatives

- Maximize lifetime of network

• Observed system behavior- Large number of false positives

- High energy consumption: lot more messages than expected

• Problem: Noisy PIR sensors• Cause: Tall grass blowing in the wind• Solution: Get facilities to mow the grass short

For every problem there is a solutionwhich is simple, clean and wrong.

— Henry Louis Mencken

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2: It’s a Cold December Morning in Albuquerque

• System: Sensor network for vehicle health management

• Our focus- System reliability

- Maximize battery life

- Easy of use

• Observed system behavior- Everything worked great night

before demo

- Nothing worked next morning

• Problem- Sensor nodes behaving erratically

• Cause: One of the crystals was rated for >0°C• Solution: Postpone demo to the afternoon

There are three intolerable things in life: cold crystals (coffee), lukewarm champagne,

and overexcited women.— Orson Welles (with apologies)

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3: Radio Waves Can’t Read “Do Not Disturb” Signs

• Situation- Multiple teams in the same hotel for sensor network

demonstrations

- Teams worked late into the night fine-tuning their software

• Problem- Next day one team finds its sensor network behaving very

strangely

• Cause- This teams sensor nodes had gotten accidentally

reprogrammed by different team working in nearby room

- Both teams were using the same default “system ID” used by the “over-the-air” programming software

• Solution: Change system ID

Whenever evil spreads, it is only by default.— Ayn Rand

Real Research?

Observations on Sensor Network Research

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Sensor Network Research

• Is this a hot area of research?- 42 conferences/workshops in 2007 with interest in

sensor networks http://www.cs.virginia.edu/~adw5p/conferences.html

• Common research topics- Sensor network services

Routing, time-synchronization, localization, management Cross-layer protocol design

- Sensor network security

- Programming Operating systems, simulation tools

• Is this research important?- Yes, but need proper perspective on importance

- Too much “old wine in new bottles” Wireless aspect of these sensor networks often ignored

vs.

When we try to do something new, we don't know what we're doing. That's the biggest challenge.

— Jeffrey Kalmikoff

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Research Needs

• Compensating for the poor quality of the sensing- Sensor malfunction most likely failure mode- Sensing channel attacks most likely security threat- Can we make up in quantity what we’ve lost in quality?

• More realistic failure models- Account for faults induced by the environment

• Scientific bases for designing, deploying and operating sensor networks- Estimates of confidence that can be placed on the data- Optimal data fusion architectures- Quantifying trade-offs

• Alternate energy sources• Don’t dream up problems to be solved

- Plenty of real problems waiting to be solved

Nature is ugly, and I prefer the monsters of my fancy to what is positively trivial

— Charles Baudelaire