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2. Contents
• Introduction
• Rover Services
• Rover Architecture
• Rover Clients
• Rover Controller
• Rover Database
• Bottlenecks
• Conclusions
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3. Introduction
“ROVER stands for Remotely
Operated Video
Enhanced Receiver system”.
Location-aware computing
involves the automatic tailoring
of information and services based
other current location of the user.
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4. Introduction(Cont…)
We have designed and implemented Rover, a
system that enables location-based services, as
well as the traditional user-
aware and device-aware services.
Traditional notions of User-aware, and
Device-aware. + Location-aware (in Rover).
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5. Introduction(Cont…)
Location service that can track the location of
every user, either by automated location
determination technology or by the user
manually entering current location.
Available via a variety of wireless access
technologies. (IEEE 802.11 wireless
LANs, Bluetooth, Infrared, cellular services)
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6. Introduction(Cont…)
 Devices
(laptop, PDA, cellular phone)
 Scales to a very large client population.
 Rover achieves this
 through fine resolution
application specific scheduling
of resources at the servers and
the network.
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7. Introduction(Cont…)
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8. Rover Services
Enables a Basic set of data services in different
media formats, including
text, graphics, audio, and video.
Transactional services coordination of state
between the clients and rover servers.
ex). e-commerce interactions.
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9. Rover Services(Cont…)
Services that require location manipulation are
a particularly important class of data services
in Rover.
Locations an important attribute of all objects
in Rover. – value, error, timestamp.
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10. Map based services
Filter : Applied to maps to select the
appropriate subset of objects to display
to the users.
Zoom : Displayed map identifies it’s
granularity.
Translate : Translated from the previously
displayed map.
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11. Rover Architecture
Rover maintains a user profile for each end-
user, that defines specific interests of the user
and is used to customize the content served.
Rover-clients are the client devices through
which users interact with Rover.
 Rover maintains a device profile for each
device.
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12. Rover physical architecture
Wireless access infrastructure
Servers
– Rover controller ( Brain of Rover system)
– Location server
– Media streaming unit
– Rover database
– Logger
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13. Rover physical architecture(Cont…)
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14. Action model
Ready-to-run: At least one action of the
server operation is eligible to be executed but
no action of the server operation is executing.
Running: One action of the server operation is
executing ( in a multi-processor setup, several
actions of the operation can be executing
simultaneously ).
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15. Action model(Cont…)
Blocked: The server operation is waiting for
asynchronous I/O response and no actions are
eligible to be executed.
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16. Action model(Cont…)
Rover technology tracks the location of
system users and dynamically configures
application-level information to different
link-layer technologies and client-device
capabilities.
A Rover system represents a single domain of
administrative control, managed and
moderated by a Rover controller.
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17. Rover Controller
17
• The interaction of the
• Rover controller with all
other components of
the system is presented .
The Rover controller
interacts with the external
world through the
following interfaces:
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18. Rover Controller(Cont…)
Location Interface:
This interface is used by the Rover
controller to query the location service about the
positions of client devices.
The location of a device is defined as a tuple
representing the estimate of its position the
accuracy of the estimate, and the time of location
measurement.
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19. Rover Controller(Cont…)
 Admin Interface:
This interface is used by system administrators
to over see the Rover system, including
monitoring the Rover controller, querying
client devices, updating security policies,
issuing system specific commands.
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20. Rover Controller(Cont…)
Content Interface:
This interface is used by the content provider
to update the content that is served by the
Rover controller to the client device
Having a separate content interface decouples
the data from the control path.
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21. Rover Database
 User InfoBase and Content InfoBase.
 Each transaction is identified
- Lock-Acquiring
- Blocking
 Avoiding Deadlocks
- Two phase Locking Protocol.
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22. Initial Implementation
Indoor and Outdoor environments.
- developed under the Linux operating
system.
- Compaq iPAQs Pocket PC.
 A GPS-device to the Compaq iPAQs and
obtained device location accuracy of
between 3-4 meters of outdoor.
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23. Initial Implementation(Cont…)
12 base stations that are distributed all over
the building and typically the client device
can receive signals from five or six of the base
stations.
get an accuracy of better than a meter in this
environment, using very simple signal strength
based estimation techniques.
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24. Bottlenecks
A large number of client requests with tight
real time constraints.
 Wireless access points
– Limited bandwidth.
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25. Conclusions
We believe that Rover Technology will
greatly enhance the user experience in a
large number places, including visits to
museums, shopping malls, game
fields, offices and business centers.
The system has been designed specifically to
scale to large user populations.
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26. Reference
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• www.rovertechnologies.com
• en.wikipedia.org/wiki/ROVER
• www.ejournal.aessangli.in
• marsrover.nasa.gov/technology
• www.indiastudychannel.com

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