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Power-Aware State Dissemination inMobile Distributed Virtual
Environments
Weidong Shi
Kalyan Perumalla
Richard FujimotoCollege of Computing, Georgia Tech
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Introduction Problem:
interactive applications execute over battery operated mobile platforms.
Goal:minimize the energy consumed by exploiting application level information.
Scheme:maintain distributed simulation state consistency while at the same time
yielding lower energy consumption.
Approach:use a closely coupled feedback loop to achieve a balance between powerconservation and simulation quality.
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Applications
Mobile Distributed Virtual Environment
Mobile Augmented Reality
Wireless Gaming
Interactive Distributed Simulation
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Power-Aware State Updates
The application exposes a slack time to the power
management service so that communication
devices can be suspended with minimal, bounded
impact on space-time consistency.
A new state update algorithm that can maximize
device suspension time while meeting minimum
latency requirements.
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Power-Aware Dead Reckoning
Algorithm
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2
4
6
8
10
12
1 2 3 4 5 6 7 8 9 10 11Time
Cons
istencyError
d
trigger a state update
Trigger calculation ofnew suspension interval
Suspension interval hint h
d
1Update Ptrue
(t) and Pdr(t) with usual dead reckoning
If there is no outstanding publication ofstate update waiting to be acked
{If | P
true(t) - P
dr(t) | > d' {
If local hosts communication device ispowered off, resume it
Send Ptrue(t) to other host(s)Set tpub = tMark that there is an outstanding
state publication not acked yet} else {
h = h + k*step;If h> MAX_SUSPENTION_TIME
Let h=MAX_SUSPENSION_TIME}
} else {If | P
true(t) - P
dr(t) | > dand
there is an un-acked state publication {Set h = ttpubSend threshold-triggering event to all other hosts
}}1Post the new h value to the underlyingmessaging mechanism.
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Consistency and Power Savings
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1
2
3
4
2 4 6 8 10 12 14 16
Dead-reckoning Threshold (pixels)
PowerSavin
gs&
Error
Baseline Error Pow er-aw are ErrorPow er Savings
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Power vs. User Input Rate
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0.2
0.4
0.6
0.8
2 4 6 8 10 12 14 16
Dead-reckoning Threshold
Power
savings
1-key per second 4-key per second
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Scalability and Consistency
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2 4 6 8 10 12 14 16
Dead-reckoning Threshold
Powe
rSavings
3-nodes 4-nodes 5-nodes
6-nodes 7-nodes 8-nodes
0
1
2
3
2 4 6 8 10 12 14 16
Dead-reckoning Threshold
Consis
tencyError
200 millisend threshold 100 millisend threshold
50 millisend threshold
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Summary Proposed a new power conservation scheme and a
new state update protocol.
Optimize the trade-off between consistency andpower reduction.
Achieve power reduction without greatly violatingconsistency constraints (9% to 69% undersimulation).
Show robustness with respect to human input rate andentity moving speed.
Achieve moderate scalability based on simulation.