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Costas BuschLouisiana State University
CCW’08
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Becomes an issue when designing algorithms
The output of the algorithms may affect the energy efficiency
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Computation power at each node is abundant◦ Unlimited energy for computations at each node◦ Computation time at each node does not affect
total time complexity
Point to point communication◦ Messages in local neighborhood can be sent
simultaneously ◦ Message delivery dominates time complexity
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The network is reliable◦ The network topology does not change◦ The messages are delivered as expected
Global Synchronization◦ All nodes can synchronize◦ A special node initiates the algorithm
The algorithm runs only once◦ One shot problems
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Computation power is limited Communication is not point-to-point
◦ Requires more energy due to channel interference
The network is unreliable (ad hoc, mobility)◦ More energy to transfer messages
Global synchronization is not easy◦ More messages, energy to achieve synchronization
An algorithm may run forever◦ It continuously consumes energy
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Consider energy consumption when designing algorithms
Do not make strong assumptions
Design algorithms with: Smaller computation at each node Low message complexity Self-stabilizing Local Online
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Classic metrics: Number of messages Total time
New metrics: Max, Average utilization of the nodes Combination of the above metrics
◦ Number of Messages X Total Time? What are realistic metrics of performance?
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Topology Control◦ Focuses on obtaining sparse connected spanners,◦ But what is the effect on load balancing?
Routing◦ Focuses on just obtaining routing paths,◦ But what is the effect on congestion?
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Peer-to-peer◦ Focus on uniformly distributing and accessing the
data◦ But what about the actual node utilization and
actual network paths?
Data aggregation◦ Focus on minimizing the total aggregation cost,◦ But how does this affect the max cost at a node?
Facility location◦ Focus on path distances◦ But how about the load on each facility?
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How frequently do uniform disc graphs appear in practice?
Can we afford to ignore maximum node utilization?
Is the computation power at each node abundant?