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 Pb−-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}=2.76 TeV measured with ALICE

Femtoscopic correlations between charged pions and kaons for different charge combinations are measured in Pb$-$Pb collisions at $\sqrt{s_{\rm NN}}=2.76$ TeV with ALICE at the LHC. The three-dimensional pion-kaon ($\pi-{\rm K}$) correlation functions and double ratios in the out-side-long pair rest frame are studied in different centrality bins. The $\pi-{\rm K}$ femtoscopic source size parameter ($R_{\rm out}$) and emission asymmetry ($\mu_{\rm out}$) 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 Pb−-Pb collisions at sNN=2.76 \mathbf{\sqrt{{\textit s}_{\rm NN}}}=2.76 TeV measured with ALICE

Two-particle femtoscopic correlations between non-identical charged particles for different charge combinations are measured in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 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 ($R_{Out}$) and emission asymmetry ($\mu$) 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