5,470 research outputs found
Energy-Aware Lease Scheduling in Virtualized Data Centers
Energy efficiency has become an important measurement of scheduling
algorithms in virtualized data centers. One of the challenges of
energy-efficient scheduling algorithms, however, is the trade-off between
minimizing energy consumption and satisfying quality of service (e.g.
performance, resource availability on time for reservation requests). We
consider resource needs in the context of virtualized data centers of a private
cloud system, which provides resource leases in terms of virtual machines (VMs)
for user applications. In this paper, we propose heuristics for scheduling VMs
that address the above challenge. On performance evaluation, simulated results
have shown a significant reduction on total energy consumption of our proposed
algorithms compared with an existing First-Come-First-Serve (FCFS) scheduling
algorithm with the same fulfillment of performance requirements. We also
discuss the improvement of energy saving when additionally using migration
policies to the above mentioned algorithms.Comment: 10 pages, 2 figures, Proceedings of the Fifth International
Conference on High Performance Scientific Computing, March 5-9, 2012, Hanoi,
Vietna
GW quasiparticle calculations with spin-orbit coupling for the light actinides
We report on the importance of GW self-energy corrections for the electronic
structure of light actinides in the weak-to-intermediate coupling regime. Our
study is based on calculations of the band structure and total density of
states of Np, U, and Pu using a one-shot GW approximation that includes
spin-orbit coupling within a full potential LAPW framework. We also present RPA
screened effective Coulomb interactions for the f-electron orbitals for
different lattice constants, and show that there is an increased contribution
from electron-electron correlation in these systems for expanded lattices. We
find a significant amount of electronic correlation in these highly localized
electronic systems.Comment: Accepted and to appear in Phys. Rev.
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