We ask the question, "for minimizing mean response time, which is preferable: one fast server of speed 1, or A; slow servers each of speed I/A:?" Our setting is the M/Gl/k system with two priority classes of customers, high priority and low priority, where G is a phase-type distribution. We find that multiple slow servers are often preferable — and we demonstrate exactly how many servers are pr...

Recall that a (hyper)graph is d-degenerate if every of its nonempty subgraphs has a vertex of degree at most d. Every d-degenerate (hyper)graph is (easily) (d + 1)colorable. A (hyper)graph is almost d-degenerate if it is not d-degenerate, but every its proper subgraph is d-degenerate. In particular, if G is almost (k − 1)-degenerate, then after deleting any edge it is k-colorable. For k ≥ 2, we...

This study deals with point and interval estimations for the scale shape parameters of component lifetime distribution a k-component series system when lifetimes are assumed to be independently identically Erlang-truncated exponential distributions. It is that components exposed progressive Type-II censoring scheme. Each failure in this plan random subject binomial distribution. Parameter obtai...

2 Stretched exponential relaxation in glassy systems 2 2.1 Mathematical properties of the stretched exponential . . . . . . . . . . . . . . . . 3 2.1.1 τ distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1.2 Behavior near zero . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1.3 Properties of G(k)/G(τ) . . . . . . . . . . . . . . . . . . . . ....

In this paper the kurtosis of the logistic-exponential distribution is analyzed. All the moments of this survival distribution are finite, but do not possess closed-form expressions. The standardized fourth central moment, known as Pearson’s coeffi cient of kurtosis and often used to describe the kurtosis of a distribution, can thus also not be expressed in closed form for the logistic-exponent...

This paper studies supply chain repairable system with a number of the same type of independent parts suppliers and the single demander. Suppose that the supply time of the component suppliers has exponential distribution, and the repair/restore time after the supply break has general continuous distribution. Using supplementary variable method, generalized Markov process theory and the Laplace...

BACKGROUND AND AIMS The distribution of photosynthetic enzymes, or nitrogen, through the canopy affects canopy photosynthesis, as well as plant quality and nitrogen demand. Most canopy photosynthesis models assume an exponential distribution of nitrogen, or protein, through the canopy, although this is rarely consistent with experimental observation. Previous optimization schemes to derive the ...