28-03-2014, 04:36 PM
Detecting User Activities using the Accelerometer on Android Smartphones
Detecting User Activities.pdf (Size: 1.87 MB / Downloads: 156)
Abstract
The purpose of this study is to identify whether
smartphones pose a security threat to the user.
The accelerometer and other sensors within the
device can be used without the users consent.
Our intent in this is to show that the accelerom-
eter can be used to obtain sensitive information
about the user. Using the magnitude of the ac-
celerometer data we found that we could iden-
tify general activities preformed by the user.
INTRODUCTION
Smartphone security is becoming increas-
ingly important as consumers rely more
and more on their smartphones to store
personal information.
With the devel-
opment of smartphone operating systems,
such as Apple’s iOs, Google’s Android and
Blakcberry’s RIM operating systems on the
rise, it is imperative that security measures
are in place to protect the privacy of the user.
This is especially true for Google’s Android
platform, being that it has an open develop-
ment environment.
What is Android?
The Android platform is an open platform
for mobile devices consisting of an operat-
ing system, applications and middleware1 .
Android gives users the opportunity to
build and publish their own applications by
providing an open development environ-
ment. Android treats all applications (na-
tive and third-party) as equals2 . Therefore,
having such an open development environ-
ment requires security measures to be taken
in order to protect the integrity of the An-
droid platform and the privacy of its users.
Data Acquisition
The device used was the Motorola Droid.
To acquire the accelerometer data, we cre-
ated an application for the Droid using the
Android SDK. Training data was acquired
by having users perform an instructed task
(e.g., walking, running, jumping) while the
data was either being exported to a server or
written to the Droid’s SD card. The applica-
tion also graphed the sampled acceleration
data, allowing for a real-time preview of the
data. Figure 1 shows a screenshot of the
application running on the Droid.
Conclusions and Future
Work
The research shows that sensors in the an-
droid platform could constitute a violation
of privacy for the users. Still to be done
on the activity recognition implementation
would be to use a better classifier that would
predict for a greater amount of people with-
out having to go through the training pro-
cess. The accelerometer proved to be a use-
ful tool in identifying activities based on
your phone’s movements and other uses of
the accelerometer could potentially include
its use in detecting key presses and even text
without the knowledge of the user. Another
interesting application would be the trans-
fer of information between phones based on
the matching acceleration values between
them.