Ricerc@Sapienza

The space-fractional and the time-fractional Poisson processes are two well-known models of fractional evolution. They can be constructed as standard Poisson processes with the time variable replaced by a stable subordinator and its inverse, respectively. The aim of this paper is to study nonhomogeneous versions of such models, which can be defined by means of the so-called multistable subordinator (a jump process with nonstationary increments), denoted by H:=H(t), t≥0.

Questo articolo tratta del modello di Ising stocastico con una temperatura che si riduce a zero con il passare del tempo. Si considera una generalizzazione della dinamica di Glauber, sulla base dell'esistenza di aggiornamenti simultanei di alcuni spin. Tali dinamiche agiscono su un'ampia classe di grafici che sono periodici. Si presume che le interazioni tra coppie di spin siano variabili aleatorie i.i.d. che seguono una distribuzione di Bernoulli con supporto -1, + 1. Il problema specifico qui analizzato riguarda la valutazione di quante volte un fissato spin cambia il suo stato.

Machine learning software accounts for a significant amount of energy consumed in data centers. These algorithms are usually optimized towards predictive performance, i.e. accuracy, and scalability. This is the case of data stream mining algorithms. Although these algorithms are adaptive to the incoming data, they have fixed parameters from the beginning of the execution. We have observed that having fixed parameters lead to unnecessary computations, thus making the algorithm energy inefficient. In this paper we present the nmin adaptation method for Hoeffding trees.

Time-lapse optical microscopy datasets from living cells can potentially afford an enormous amount of quantitative information on the relevant structural and dynamic properties of sub-cellular organelles/ structures, provided that both the spatial and temporal dimensions are properly sampled during the experiment. Here we provide exemplary live-cell, time-lapse confocal imaging datasets corresponding to three sub-cellular structures of the endo-lysosomal pathway, i.e. early endosomes, late endosomes and lysosomes, along with detailed guidelines to produce analogous experiments.