We consider a facility location problem, where the objective is to “disperse” a number of facilities, i.e., select a given number k of locations from a discrete set of n candidates, such that the average distance between selected locations is maximized. In particular, we present algorithmic results for the case where vertices are represented by points in d-dimensional space, and edge weights co...

We provide an asymptotic linear representation for the Breslow estimator for the baseline cumulative hazard function in the Cox model. The representation consists of an average of independent random variables and a term involving the difference between the maximum partial likelihood estimator and the underlying regression parameter. The order of the remainder term is arbitrarily close to n−1.

A technique for isolating and establishing long-term cultures of rat urinary bladder epithelium has been devised. Cells isolated and cultured by this method have been grown for 12 weeks without subculturing. Rat bladder epithelial cells require the addition of putrescine, spermine, and spermidine to attain maximum growth and long-term survival. Monolayer cultures have been subcultured and carri...

HIV dynamics studies, based on differential equations, have significantly improved the knowledge on HIV infection. While first studies used simplified short-term dynamic models, recent works considered more complex long-term models combined with a global analysis of whole patient data based on nonlinear mixed models, increasing the accuracy of the HIV dynamic analysis. However statistical issue...

The volatility structure of 90-day bill futures traded on the Sydney Futures Exchange is analysed within the framework of the Heath-Jarrow-Morton model. The method involves characterisation of the transition probability density function for the forward rate process represented by the stochastic differential equation in the arbitrage-free economy. Maximisation of the likelihood function then res...

This paper proposes a simple class of threshold autoregressive model for purpose of forecasting daily maximum ozone concentrations in Southern California. Linear time series model has been widely considered in environmental modeling. However, this class of models fails to capture the nonlinearity in ozone process and the complexity of meteorological interactions with ozone. In this article, we ...

In this work, we study, analytically and employing Monte Carlo simulations, the influence of the competition between several activity-dependent synaptic processes, such as short-term synaptic facilitation and depression, on the maximum memory storage capacity in a neural network. In contrast to the case of synaptic depression, which drastically reduces the capacity of the network to store and r...