NrBAlone
Native Community Search Mobile Application
Class Code: EEL 6788
Date: 04-18-2011
Instructor: Dr. Damla Turgut
Presenter: Taranjeet Singh Bhatia
Abstract
An urban sensing smart phone application
which enables new arrivals into a
cosmopolitan community to locate people
of their own native country. The
application, which runs on Android
phones, detects and displays the other
members of the community which are in
200 meter proximity of the user.
Application Usage Scenarios
A student who has recently entered into foreign land for education somehow
manage to get living resource but do not feel at home. The display on his
device reinforces his senses to integrate within his neighborhood, and
reassure him that native country people are nearby. But he does not have
any idea to approach or even find out how many are surround him
A new immigrant family is looking for secure and familiar living neighborhood
in foreign land. They visited a quiet and sophisticated township for buying
new home but they do not have any immediate idea about number of
families’ who are their country-native living in that township
During long distance journey we normally find co-country familiar stranger
sitting next to us but due to lack of confidence about their origin we gain
hesitation in starting conversation
Application overview
Application overview
Download manager
Map Display
GPS Sensor
Back Light Status
Accelerometer
Sensor
Update Service
Uploading manager
Application Feature
1.
2.
3.
4.
5.
6.
Optimized power consumption using adaptive GPS interval
No past data saved on server reducing the risk of tracking users
location history
User identity saved on server in non-reversal encrypted form
Maximum of 20 user will be visible on map which reduces the data
download
Proximity of user is restricted to 200m distance
User can see common information shared by other users
System Requirement


Continuously monitoring User Location
Reduced Power consumption by Sensor such as
Accelerometer and GPS sensor

Reduced data transfer usage

User Privacy
Power Consumption Tests And Results:
1. Test 1: GPS ON without loading a GPS enabled application
Result: 5 hours later: 92% battery remaining
2. Test 2: GPS ON with continuous GPS tracking application
running in the background
Result: 5 hours later: 30% battery remaining
3. Test 3: Accelerometer ON by Elixir app accelerometer test
function
Result: 5 hour later: 1% battery remaining
Optimizing power consumption using adaptive GPS
interval
Case 1:
Condition: If less than 5 meter of distance is covered by user in two consecutive GPS
coordinates with update frequency of 20s
Assumptions: User is not using mobile phone or sitting or standing
Action:
1. Start Accelerometer
2. When the device is in static condition such as kept on a table (and obviously not
accelerating), the accelerometer reads a magnitude of g = 9.81 m/s2 on Z- axis. In
this circumstance we can reduce the frequency of GPS update by the exponential
factor of 2seconds in next iteration of GPS location fetch. This reduction in GPS
update occurs continuously until maximum value of 10 min is reached. At this upper
limit, it will be assumed that user is sleeping and so shut down GPS update. Start
polling for other event such as screen backlight turn on or keypad unlock event to
start GPS update again with initial update frequency of 20s.
Optimizing power consumption using adaptive GPS
interval
3. When the user is in static condition and not moving very frequently such as at
community gathering or Waiting for bus, the accelerometer reads a magnitude of g
on Z axis other than 9.81 m/s2. In this condition, we can reduce the frequency of
GPS update by the constant increment of 10 seconds in next iteration of GPS
location fetch. This reduction in GPS update occurs continuously until GPS update
maximum value of 10 min is reached.
4. Whenever new GPS coordinate occur it will be update on server too
Optimizing power consumption using adaptive GPS
interval
Case 2:
Condition: If 1-10 meter of distance is covered by user in two consecutive GPS
coordinates with update frequency of 20s
Assumptions: User is walking or running or playing some sports such as basketball or
football.
Action: No changes require in GPS update frequency. As application covers the 200
meter of radius we need to keep the track of user location in this case. As this
condition will not last for long time we do not need to change the GPS location
update frequency. Whenever new GPS coordinate occur it will be update on server
too
Optimizing power consumption using adaptive GPS
interval
Case 3:
Condition: If more than 10 meter of distance is covered by user in two consecutive GPS
coordinates with update frequency of 20s
Assumptions: User is bicycling or driving or using transport
Action: In this circumstance we reduce the frequency of GPS update by the power of 2
in next iteration of GPS coordinate fetch. This reduction in GPS update occurs
continuously until maximum value of 10 min is reached. In this case, we are not
uploading the GPS coordinate on server because user is moving fast and will exist
shorter at one place which make his location difficult to appear in the proximity of
other users.
Future Implementation
Ability to initiate chat, SMS or email from within the NrBAlone application.
Ability to broadcast notifications to all the nearby members of a specific
community. This would enable application scenarios such as car pooling for
shopping trips, car pickup for commute, organization of instant events and
special offers from merchants and restaurants of interest to a specific
community.
The tools will be used to collect statistical data about the geographical and
temporal distribution of members of communities as well as their interaction
patterns.
NrBAlone
Demo