Analysis of power-down systems with five states.

摘要

We consider a device, which has states ON, OFF and fixed number of intermediate states.In the ON state the device uses full power whereas in the OFF state the device consumes no energy but a constant cost is associated with switching back to ON. Intermediate states use some fraction of energy proportional to the usage time but switching back to the ON state has a constant setup cost depending on the current state. Such systems are widely used to conserve energy, for example to speed scale CPUs, to control data centers, or to manage renewable energy.;We analyze such a system in terms of competitive analysis and give a heuristic for finding optimal online algorithms. We then use our approach to discuss five-state systems which are widely used in practice.