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Location Based Time Capsule on Android

Meng ChengQin Huang

Yiteng ZhangZhong Ren

Overview

“Sensing data without knowing the location is meaningless.”

User can save a message inside a “capsule” and bind it to a certain time and/or location

Leave the “capsule” for him/herself or for other users Potential use cases:

Birthday/anniversary greetings Location-based reminders Leave a note for whoever comes to Yale Send a message to the future self

Client

Easy, smooth navigation using Fragments Send capsule to other users from the contact

list User can directly select any location on the map Conveniently select any date/time on the

calendar

Server

MySQL + JDBC HTTP + JSON

http://<server>/contacts?user_id=<userid> {"contacts":[{"id":1,"name":"zr36"},{"id":2,"name":"yry3"}]}

DB connection pool to support concurrent access Commit / rollback to ensure data integrity Optimized search on location

GCM Service

Each device has a unique key for GCM The key registered both on GCM and Server Push time/location capsule to user’s device Instantaneous and Energy-efficient

What is novel?

Users can define a “capsule” in three dimensions: Time Location User visibility

Server can instantaneously push matched capsule via GCM to the corresponding users

What is substantial?

Client adaptively updates its location Adjust update interval according to the search

result on the server and the location change of the device

Extend battery life time Server adaptively searches for location capsules

Search inside a latitude/longitude-bounded square centered at the client’s location

If no match found, enlarge the search square and reduce the update rate of the device

Future Improvements

More furnished UI More efficient server setup e.g. MongoDB Enable capsules to store pictures or audio Use Amazon S3 to separate persistent storage

from application server Integration with Facebook / Google+

Demo

Thanks for your attention!