We propose a two-dimensional geometrical model that takes into account geometrical effects of frustration in the rearrangement processes in granular systems. In particular we related the microscopic motor of compaction to the need of cooperative rearrangements in order to find a better packing....

We analyze the non-equilibrium relaxation properties of granular materials in the perspective of a cooperative length approach of Adam and Gibbs. The existence of complex geometrical interactions between the grains induces a rough landscape in the structure of the allowable phase space and in...

How often will elections end in landslides and what is the probability for a head-to-head race? Analyzing ballot results from several large countries rather anomalous and yet unexplained distributions have been observed. We identify tactical voting as the driving ingredient for the anomalies and...

The design of efficient large scale networks is a common problem in Operations Research. Some of those, such as electric power grids, transportation systems, communication networks, and others, must maintain their efficiency even after several failures, or malicious attacks. In this work, we...

We disclose that only considering the largest cluster suffices to obtain a first-order percolation transition. As opposed to previous realizations of explosive percolation our novel models obtain Gaussian cluster distributions and compact clusters as one would expect at first-order transitions....

Motivated by experimental results in granular media, and some recently proposed scalar force models for these materials, some aspects of packing properties and their force distributions are studied in a frustrated Ising lattice gas.

A new trend in physics, namely the building of special purpose computers (SPC), is reviewed. Special emphasis is given to the following questions: Why does one build SPC's? When is it worthwhile to build an SPC? How does one proceed if one wants to build an SPC? Finally the most important...

We study several deterministic one-dimensional traffic models. For integer positions and velocities we find the typical high and low density phases separated by a simple transition. If positions and velocities are continuous variables the model shows self-organized critically driven by the...

We study numerically the avalanches in a two-dimensional critical height sandpile model with sand grains added at the center of the systems. Smaller avalanches near the center of the system are isotropic. Larger avalanches are, however, affected by the boundary of the system, to a degree that...

Rocks and ceramics are the typical prototypes for brittle materials. When they are very strongly sheared they can also flow plastically if the hydrostatic pressures are strong enough. Both cases have been studied extensively experimentally and numerically. The cracks in the brittle case and the...