Self-organized Density Research Articles

Macro SOStream: An Evolving Algorithm to Self Organizing Density-Based Clustering with Micro and Macroclusters

This paper proposes a new evolving algorithm named Macro SOStream with entirely online learning and based on self-organizing density for data stream clustering. The Macro SOStream is based on the SOStream algorithm, but we incorporate macroclusters composed of microclusters. While microclusters have spherical shapes, macroclusters can have arbitrary shapes. Moreover, the Macro SOStream has the macrocluster merge functionality specially designed to improve its performance under data drift contexts. The Macro SOStream’s performance is compared to SOStream and DenStream algorithms’ performance using four synthetic datasets and the ARI performance metric to validate our proposal. Furthermore, we carry out an exhaustive analysis on the influence of adequate hyperparameter setup on these algorithms’ performance. As a result, the Macro SOStream presents good performance mainly in the context of data drift and for demands of non-spherical clusters.

Molecular motor traffic: From biological nanomachines to macroscopic transport

All cells of animals and plants contain complex transport systems based on molecular motors which walk along cytoskeletal filaments. These motors are rather small and have a size of 20–100 nm but are able to pull vesicles, organelles and other types of cargo over large distances, from micrometers up to meters. There are several families of motors: kinesins, dyneins, and myosins. Most of these motors have two heads which are used as legs and perform discrete steps along the filaments. Several aspects of the motor behavior will be discussed: motor cycles of two-headed motors; walks of single motors or cargo particles which consist of directed movements interrupted by random, diffusive motion; cargo transport through tube-like compartments; active diffusion of cargo particles in slab-like compartments; cooperative transport of cargo by several motors which may be uni- or bi-directional; and systems with many interacting motors that exhibit traffic jams, self-organized density and flux patterns, and traffic phase transitions far from equilibrium. It is necessary to understand these traffic phenomena in a quantitative manner in order to construct and optimize biomimetic transport systems based on motors and filaments with many possible applications in bioengineering, pharmacology, and medicine.