We study the on-line version of the well known problem of scheduling a set of $n$ independent multiprocessor tasks with prespecified processor allocations on a set of identical processors in order to minimize the makespan. Recently, it has been proven that even in the off-line case with unit processing time tasks no polynomial time approximation algorithm can be found with approximation factor $m^{{1}/{2}-\eps}$ for any $\eps >0$, unless \NP=\ZPP. We first study simple approximation and on-line algorithms based on the classical first-fit technique.

We present a multiscale approach to the modeling of polymer dynamics in the presence of a fluid solvent. The approach combines Langevin molecular dynamics ( MD) techniques with a mesoscopic lattice Boltzmann (LB) method for the solvent dynamics. A unique feature of the present approach is that hydrodynamic interactions between the solute macromolecule and the aqueous solvent are handled explicitly, and yet in a computationally tractable way due to the dual particle-field nature of the LB solver.

PELCR is an environment for lambda-terms reduction on parallel/distributed computing systems. The computation performed in this environment is a distributed graph rewriting and a major optimization to achieve efficient execution consists of a message aggregation technique exhibiting the potential for strong reduction of the communication overhead. In this paper we discuss the interaction between the effectiveness of aggregation and the schedule sequence of rewriting operations. Then we present a Priority Based (BP) scheduling algorithm well suited for the speci c aggregation technique.

The need for anti-HIV-1 vaccines is universally recognized. Although several potential vaccine formulations are being tested in clinical trials, the complexity of the viral system and the length of the experimentation required and its costs makes the goal of obtaining such a vaccine still elusive. We have built a mathematical model for the simulation of HIV-1 infection spreading into the body, which allows us study in silico the effect of hypothetical anti-HIV-1 vaccines having different properties.

We present a mesoscopic lattice model for non-ideal fluid flows with directional interactions, mimicking the effects of hydrogen bonds in water. The model supports a rich and complex structural dynamics of the orientational order parameter, and exhibits the formation of disordered domains whose size and shape depend on the relative strength of directional order and thermal diffusivity.

The statistical properties of velocity and acceleration fields along the trajectories of fluid particles transported by a fully developed turbulent flow are investigated by means of high resolution direct numerical simulations. We present results for Lagrangian velocity structure functions, the acceleration probability density function, and the acceleration variance conditioned on the instantaneous velocity. These are compared with predictions of the multifractal formalism, and its merits and limitations are discussed.

Precise knowledge of X-ray diffraction profile shape is crucial in the investigation of the properties of matter in crystals powder. Line-broadening analysis is the fourth pre-processing step in most of the full powder pattern fitting softwares. The final result of line-broadening analysis strongly depends on three further steps: noise filtering, removal of background signal, and peak fitting. In this work a new model independent procedure for two of the aforementioned steps (background suppression and peak fitting) is presented.

Sharp constants are exhibited in exponential inequalities corresponding to the limiting case of the Sobolev inequalities in Lorentz-Sobolev spaces of arbitrary order.

Cloud detection from geostationary satellite multispectral images through statistical methodologies is investigated. Discriminant analysis methods are considered to this purpose, endowed with a nonparametric density estimation and a linear transform into principal and independent components. The whole methodology is applied to the MSG-SEVIRI sensor through a set of test images covering the central and southern part of Europe.