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Discrete-time queues with zero-regenerative arrivals: moments and examples
In this paper we investigate a single-server discrete-time queueing system with single-slot service times. The stationary ergodic arrival process this queueing system is subject to, satisfies a regeneration property when there are no arrivals during a slot. Expressions for the mean and the variance of the queue content in steady state are obtained for this broad class which includes among others autoregressive arrival processes and M/G/infinity-input or train arrival processes. To illustrate our results, we then consider a number of numerical examples
Deep space experiment to measure
Responding to calls from the National Science Foundation (NSF) for new
proposals to measure the gravitational constant , we offer an interesting
experiment in deep space employing the classic gravity train mechanism. Our
setup requires three bodies: a larger layered solid sphere with a cylindrical
hole through its center, a much smaller retroreflector which will undergo
harmonic motion within the hole and a host spacecraft with laser ranging
capabilities to measure round trip light-times to the retroreflector but
ultimately separated a significant distance away from the sphere-retroreflector
apparatus. Measurements of the period of oscillation of the retroreflector in
terms of host spacecraft clock time using existing technology could give
determinations of nearly three orders of magnitude more accurate than
current measurements here on Earth. However, significant engineering advances
in the release mechanism of the apparatus from the host spacecraft will likely
be necessary. Issues with regard to the stability of the system are briefly
addressed.Comment: 13 pp, 3 figs, accepted CQ
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