Some results of the queueing system E/M/c

This paper analyses the E/M/c queueing system and shows how to calculate the expected number in the system, both at a random epoch and immediately preceding an arrival. These expectations are expressed in terms of certain initial probabilities which are determined by linear equations. The advantages and disadvantages of this method are also discussed.     

Congestion tolls: Equilibrium and optimality

An example of a network with flow costs depending on congestion is presented for which no system of tolls and subsidies exists which can ensure that all equilibria in the game of route selection are Pareto optimal.     

The M/G/1 queue with instantaneous bernoulli feedback

In this paper we are concerned with several random processes that occur in M/G/1 queues with instantaneous feedback in which the feedback decision process is a Bernoulli process. Queue length processes embedded at various times are studied. It is shown that these do not all have the same asymptotic distribution, and that in general none of the output, input, or feedback processes is renewal. These results have implications in the application of certain decomposition results to queueing networks.     

On convexity proofs in location theory

It is often assumed in the facility location literature that functions of the type ø_i(x_i, y) = β_i[(x_i-x)²+(y_i-y)²]^K/2 are twice differentiable. Here we point out that this is true only for certain values of K. Convexity proofs that are independent of the value of K are given.     

Markov chain with taboo states and reliability

A computationally feasible matrix method is presented to find the first-passage probabilities in a Markov chain where a set of states is taboo during transit. This concept has been used to evaluate the reliability of a system whose changes in strength can be thought of as a Markov chain, while the environment in which it is functioning generates stresses which can also be envisaged as another Markov chain.     

Multivariate dependent relevations with applications,and related topics

“Relevation” is the name given by Krakowski to the distribution of failure time of a replacement from an aging stock. The present authors have extended this concept to include (i) hierarchal replacement systems and (ii) dependence between lifetimes of original and replacement items. In this article, we present some further developments, including first steps toward a synthesis of (i) and (ii).     

The mother of all post-mortems

The most striking finding of the Chilcot Report is that the record reveals little that was previously unknown. A key point for its authors is that diplomatic alternatives had not been exhausted when the US and UK went to war. But, short of an armed attack by the other side, it is hard to say when they would have been. Here what was crucial was the belief shared by Bush and Blair that Saddam Hussain would not and could not change. For the British the issue of whether alternatives to war remained is particularly important because of its implications for international law, something that did not trouble the Americans. It remains unclear if Blair would have gained or lost leverage over Bush had he made British participation contingent on better American policy, for example on developing a workable plan for the reconstruction of Iraq.