27,413 research outputs found
Qualitative Properties of alpha-Weighted Scheduling Policies
We consider a switched network, a fairly general constrained queueing network
model that has been used successfully to model the detailed packet-level
dynamics in communication networks, such as input-queued switches and wireless
networks. The main operational issue in this model is that of deciding which
queues to serve, subject to certain constraints. In this paper, we study
qualitative performance properties of the well known -weighted
scheduling policies. The stability, in the sense of positive recurrence, of
these policies has been well understood. We establish exponential upper bounds
on the tail of the steady-state distribution of the backlog. Along the way, we
prove finiteness of the expected steady-state backlog when , a
property that was known only for . Finally, we analyze the
excursions of the maximum backlog over a finite time horizon for . As a consequence, for , we establish the full state space
collapse property.Comment: 13 page
Ground State Energy for Fermions in a 1D Harmonic Trap with Delta Function Interaction
Conjectures are made for the ground state energy of a large spin 1/2 Fermion
system trapped in a 1D harmonic trap with delta function interaction. States
with different spin J are separately studied. The Thomas-Fermi method is used
as an effective test for the conjecture.Comment: 4 pages, 3 figure
Pointed Hopf Algebras with classical Weyl Groups
We prove that Nichols algebras of irreducible Yetter-Drinfeld modules over
classical Weyl groups supported by are
infinite dimensional, except in three cases. We give necessary and sufficient
conditions for Nichols algebras of Yetter-Drinfeld modules over classical Weyl
groups supported by to be finite dimensional.Comment: Combined with arXiv:0902.4748 plus substantial changes. To appear
International Journal of Mathematic
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