We study phase transitions in models of opinion formation which are based on the social impact theory. Two different models are discussed: (i) a cellular-automata-based model of a finite group with a strong leader where persons can change their opinions but not their spatial positions, and (ii)...

We study a model of opinion formation based on the theory of social impact and the concept of cellular automata. The case is considered when two strong agents influence the group: a strong leader and an external social impact acting uniformly on every individual. There are two basic stationary...

In many social dilemmas, individuals tend to generate a situation with low payoffs instead of a system optimum ("tragedy of the commons"). Is the routing of traffic a similar problem? In order to address this question, we present experimental results on humans playing a route choice game in a...

The influence of node–node degree correlations on distances in complex networks has been studied. We have found that even the presence of strong correlations in complex networks does not break a universal scaling of distances between vertices of such networks as science collaboration networks,...

In the present study we consider relations between companies in Poland taking into account common branches they belong to. It is clear that companies belonging to the same branch compete for similar customers, so the market induces correlations between them. On the other hand two branches can be...

We measure the content of random uncorrelated noise in heart rate variability using a general method of noise level estimation using a coarse-grained entropy. We show that usually, except for atrial fibrillation, the level of such noise is within 5–15% of the variance of the data and that the...

Periodical perturbations of market dynamics are analyzed using a method of time scales separation similar to the approach that is usually applied for the analysis of Kapitza pendulum. It is shown that if the perturbations are fast enough then the market oscillates around a new equilibrium price...

Interbank deposits (loans and credits) are quite common in banking system all over the world. Such interbank co-operation is profitable for banks but it can also lead to collective financial failures. In this paper, we introduce a new model of directed percolation as a simple representation for...

We investigated distributions of short term price trends for high frequency stock market data. A number of trends as a function of their lengths were measured. We found that such a distribution does not fit to the results following from an uncorrelated stochastic process. We proposed a simple...

We give a microscopic explanation of both Debye and non-Debye thermalization processes that have been recently reported by Gall and Kutner [Physica A 352 (2005) 347]. Due to reduction of the problem to first passage phenomena we argue that relaxation functions f(t) introduced by the authors...