Christian RohnerPer Gunningberg

Uppsala Universitet, Sweden

Twitter in Disaster Mode:Opportunistic Communication and

Distribution of Sensor Data in Emergencies

Theus HossmannFranck Legendre

Paolo CartaETH Zurich, Switzerland

2hossmann@tik.ee.ethz.ch

Source: XKCD (http://xkcd.com/723/)

3hossmann@tik.ee.ethz.ch

Source: Twitter Blog (http://blog.twitter.com/2011/06/global-pulse.html)

Network Outage in Japan

4hossmann@tik.ee.ethz.ch

Operator # inoperative BS

NTT DoCoMo 6720

KDDI 3800

Softbank 3786

Your Smart Phone, the Emergency Kit

• Temporary GSM network• Wireless mesh network• Satellite communication

• Opportunistic Communication• DTN2• Haggle• PodNet

5hossmann@tik.ee.ethz.ch

Deployment, configuration, etc.• Requires experts• > 1-2 days

✗• No expert skills required• Instantly ready✓

Goal: Enable disaster victims to tweet instantaneouslyGoal: Enable disaster victims to tweet instantaneously

6hossmann@tik.ee.ethz.ch

Twimight

• Simple yet flexible• Wide spread (200M users)

• Simple yet flexible• Wide spread (200M users)

• Wide spread • Developer friendly• Wide spread • Developer friendly

• Disaster Mode (user enabled with a simple settings check-box)

✓ Opportunistic Communication

✓Spreading of sensor data

• Disaster Mode (user enabled with a simple settings check-box)

✓ Opportunistic Communication

✓Spreading of sensor data

• Open source (Google Code)

• Open source (Google Code)

Opportunistic Spreading of Tweets

• Bluetooth communication• Requires pairing• Scanning (2min ± 20sec)

• Power saving heuristic• Reduced scanning interval at battery levels < 50%• No more scanning at levels below 30%

• Epidemic spreading (flooding)• Small data volumes• FIFO buffer

• Publish tweets once connectivity is restored7hossmann@tik.ee.ethz.ch

Tweeting of Sensor Data

• Twimight plugin: Accessing disaster tweet DB• User activity detection

• Monitoring acceleration sensor• Classify: {Still | walking | running}• Nearest Neighbor classification

• Environment detection• Monitoring microphone• Classify: {Silence | Speech | Music}• Decision tree classification

• Posting tweet on activity change

8hossmann@tik.ee.ethz.ch

Das et al. “Detecting User Activities using the Accelerometer on Android Smartphones“

Das et al. “Detecting User Activities using the Accelerometer on Android Smartphones“

Lu et al. “SoundSense: Scalable Sound Sensing for People-CentricApplications on Mobile Phones“

Lu et al. “SoundSense: Scalable Sound Sensing for People-CentricApplications on Mobile Phones“

What’s next?

9hossmann@tik.ee.ethz.ch

• Security (in progress)• Asymmetric crypto for signing (tweets) and encrypting (DM)• “Pragmatic” hybrid approach: Key distribution before

disaster• Twitter Disaster Server

• Smart tweet delivery• Contact Graph based routing for Direct Messages• Interest matching for tweets

• In parallel• Improvements in User Interface• Advanced Plugin System: Browse and install plugins within

Twimight• Plugins, plugins, plugins…

Get Involved

• Twimight: http://code.google.com/p/twimight• Sensor:

http://code.google.com/p/android-sensor-twitteth/

10hossmann@tik.ee.ethz.ch

Video

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12hossmann@tik.ee.ethz.ch

Thank You For Installing & Using Twimight