The cloud is generally used for data storage and service provision. Cloudlets can also be used to
provide the mentioned things. The provision of a large number of cloud services in a cloudlet
scenario would be beneficial, however, for this project a single service will be offered due to time
constraints. There are numerous aspects the current cloud computing paradigm is lacking in, these
limitations carry over to cloudlets. The following are the motivational factors of the project.
- Information Ownership, Control and Security: Data centres for cloud computing service
providers can be located in any country in the world. Users may be concerned about where
their information is stored. Users may want the ability to control where their data is stored
and who has access to it. This may be due to privacy laws and government organizations in
- Cellular networks: Connecting to the Internet via cell phone networks is generally slower
than connecting to local WiFi networks. They also introduce high charges from cell phone
providers in some cases. These two factors therefore limit the use of cloud services by users
of mobile devices.
The project focusses on the following two research questions:
- Can we create an effective common sandbox for data?
- What interface conceptual metaphors are effect in conveying the properties of the
cloudlets as ephemeral data stores?
An application was developed that allowed file sharing between Android devices connected to the
This investigation set out to evaluate the feasibility of a Cloudlet running on the Raspberry Pi to
allow co-located file sharing between users with smartphones. An experimental design process was
used which allowed for incremental improvements on the system and its interface after each phase.
Here is a general overview of the design process that occurred:
- Design of initial paper prototypes (P1);
- Heuristic evaluation of those paper prototypes (using P1);
- Re-design of the paper prototypes (P2);
- Carrying out participant observations with the paper prototypes (using P2);
- Re-design of the paper prototypes to get final paper prototypes (P3);
- Implementing the system (I1 using P3);
- Carrying out the first HCI expert evaluation on the implementation (using I1);
- Re-design of the implementation (I2);
- Carrying out a second HCI expert evaluation (using I2)(It should be noted
at this point a third implementation (I3) couldn’t be developed due to time constraints).
- Carrying out usability testing (using I2)
The key research questions included:
- Determining if a common sandbox (public digital table/shelve) for ephemeral data (i.e.
data that’s not permanently on the cloudlet) could be implemented and used in a practical
setting. This was a success but it could be investigated further because although it was
implemented on the Android OS and tested on Samsung Galaxy Pockets, to fully test the
practicality of a common sandbox, the application would have to be implemented on other
mobile devices running on different software (e.g. having a cloudlet with Apple, Android
and BlackBerry devices all sharing files). However, implementing it on different mobile
operating systems was out of the projects scope.
- Determining if there is an effective interface for conveying the cloudlet and the ephemeral
nature of the file shared. This was fairly successful because most users understood the
functions of the cloudlet immediately after completing a few short tasks on the cloudlet
in one session. However, the final HCI expert evaluation pointed out ways in which the
interface could be improved slightly to convey the conceptualisation better.
The Cloudlet app was met with fair enthusiasm with the user groups and there was genuine interest
in using the Cloudlet beyond the scope of the project. The success can be attributed to carrying out
evaluations and getting feedback along the design process which led to revamping the application a
An interesting lesson learned during this project was the effectiveness of using different ways to
evaluate the system. This allowed for flaws to be pointed out which were missed by other methods
on previous phases. For example, users didn’t notice that the conceptualisation of the cloudlet
(namely, the conference table) may have been difficult to get in the first participant observation
however this issue was brought to the light right after in the first expert evaluation.
third implementation (I3) couldn’t be developed due to time constraints).
- Jarvis Mutakha