11,134 research outputs found
Safe Schedulability of Bounded-Rate Multi-Mode Systems
Bounded-rate multi-mode systems (BMMS) are hybrid systems that can switch
freely among a finite set of modes, and whose dynamics is specified by a finite
number of real-valued variables with mode-dependent rates that can vary within
given bounded sets. The schedulability problem for BMMS is defined as an
infinite-round game between two players---the scheduler and the
environment---where in each round the scheduler proposes a time and a mode
while the environment chooses an allowable rate for that mode, and the state of
the system changes linearly in the direction of the rate vector. The goal of
the scheduler is to keep the state of the system within a pre-specified safe
set using a non-Zeno schedule, while the goal of the environment is the
opposite. Green scheduling under uncertainty is a paradigmatic example of BMMS
where a winning strategy of the scheduler corresponds to a robust
energy-optimal policy. We present an algorithm to decide whether the scheduler
has a winning strategy from an arbitrary starting state, and give an algorithm
to compute such a winning strategy, if it exists. We show that the
schedulability problem for BMMS is co-NP complete in general, but for two
variables it is in PTIME. We also study the discrete schedulability problem
where the environment has only finitely many choices of rate vectors in each
mode and the scheduler can make decisions only at multiples of a given clock
period, and show it to be EXPTIME-complete.Comment: Technical report for a paper presented at HSCC 201
Calvin Massey: Gentleman and Scholar
I first met Calvin Massey in person in 1994, when I joined the U.C. Hastings faculty. However, I knew of and admired Calvin’s scholarship long before that. Six years earlier, I was a law student at the University of Chicago, and a student editor at the law review. In that role, I helped cite-check and edit a major article authored by Calvin, as well as a series of short responses by Calvin and other scholars, debating the meaning and scope of the Eleventh Amendment to the U.S. Constitution. I was struck then, and continue to be amazed, by the clarity, thoroughness, and intellectual rigor of this exchange, and especially Calvin’s contributions to it. I truly believe that these papers provide a model for what engaged, respectful, and careful scholarly debate should look like. They certainly provided an inspiration to me as I began my scholarly career, just as Calvin provided crucial mentorship during my early years at Hastings. In this brief essay I summarize this intellectual exchange, and explain why I think it epitomizes Calvin’s extraordinary strengths as a scholar, and as a gentleman
High Energy electron and proton acceleration by circularly polarized laser pulse from near critical density hydrogen gas target
We demonstrate in this research the quasi-monoenergetic electron and proton
acceleration through three dimensional particle-in-cell simulations of short
petawatt circular polarized laser pulse interactions with near critical density
hydrogen target. We numerically show that under controlled choice of laser and
target parameters, the high energy electrons and protons can be illustrated in
experiment at advanced high power laser facilities eg ELI - ALPS. We detailed
the microphysics involved in the acceleration mechanism, which required
investigating the role of plasma density gradients, plasma density, and target
thickness. The role of selfgenerated plasma electric and magnetic fields is
depicted on proton energy and density distribution. We numerically investigate
here the laser driven proton acceleration where energetic protons with energies
more than 200 MeV and charge in excess of 10 nC and conversion efficiency more
than 6 percent (which implies 2.4 J proton beam out of the 40 J incident laser
energy). Additionally and interestingly, we show from simulation study first
time the quasi-monoenergetic ring shaped electron beam driven by circularly
polarised laser which may prove useful for plasma based-based X-ray source and
collimation of positron beam
Pion-kaon femtoscopy in PbPb collisions at TeV measured with ALICE
Femtoscopic correlations between charged pions and kaons for different charge
combinations are measured in PbPb collisions at TeV
with ALICE at the LHC. The three-dimensional pion-kaon ()
correlation functions and double ratios in the out-side-long pair rest frame
are studied in different centrality bins. The femtoscopic source
size parameter () and emission asymmetry () are
extracted. It is observed that the average source size of the system and the
emission asymmetry between pions and kaons increase from peripheral to central
events.Comment: 4 pages, 4 figures, Proceedings of XXVIIth International Conference
on Ultrarelativistic Nucleus-Nucleus Collisions (Quark Matter 2018
Non-identical particle femtoscopy in PbPb collisions at TeV measured with ALICE
Two-particle femtoscopic correlations between non-identical charged particles
for different charge combinations are measured in Pb-Pb collisions at
= 2.76 TeV with ALICE at the LHC. The three-dimensional
two-particle correlation functions are studied in different centrality bins.
The femtoscopic source size parameter () and emission asymmetry
() are extracted. It is observed that the average source size of the
system and emission asymmetry between particles increase from peripheral to
central events.Comment: 3 pages, 2 figures, Proceedings of XXXIX International Conference on
High Energy Physics (ICHEP 2018
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