117 research outputs found
A double-ended queue with catastrophes and repairs, and a jump-diffusion approximation
Consider a system performing a continuous-time random walk on the integers,
subject to catastrophes occurring at constant rate, and followed by
exponentially-distributed repair times. After any repair the system starts anew
from state zero. We study both the transient and steady-state probability laws
of the stochastic process that describes the state of the system. We then
derive a heavy-traffic approximation to the model that yields a jump-diffusion
process. The latter is equivalent to a Wiener process subject to randomly
occurring jumps, whose probability law is obtained. The goodness of the
approximation is finally discussed.Comment: 18 pages, 5 figures, paper accepted by "Methodology and Computing in
Applied Probability", the final publication is available at
http://www.springerlink.co
Design, optimization and experimental characterization of RF injectors for high brightness electron beams and plasma acceleration
In this article, we share our experience related to the new photo-injector
commissioning at the SPARC\_LAB test facility. The new photo-injector was
installed into an existing machine and our goal was not only to improve the
final beam parameters themselves but to improve the machine handling in
day-to-day operations as well. Thus, besides the pure beam characterization,
this article contains information about the improvements, that were introduced
into the new photo-injector design from the machine maintenance point of view,
and the benefits, that we gained by using the new technique to assemble the gun
itself
Effect of N-acetylcysteine and allopurinol combination to protect spinal cord ischemia/reperfusion injury induced by aortic cross-clamping in rat model
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