KINETIC PHASE TRANSITION IN HONEYBEE FORAGING DYNAMICS: SYNERGY OF INDIVIDUAL AND COLLECTIVE

We consider a honeybee colony as a dynamical system gathering information from an environment and accordingly adjusting its behavior. Collective foraging behavior is shown to be triggered by the change of either colony size or profitability of exploited nectar sources. The collective mode provides greater productivity compared to the individual one. The latter does not diminish the importance of individual behavior that ensures the adaptivity of the system. Thus, the transition from the phase of individual behavior to a more complex phase, combining both individual and collective modes, provides the most effective scenario of honeybee colony foraging.

The combined effect of attraction and orientation zones in 2D flocking models

In nature, many animal groups, such as fish schools or bird flocks, clearly display structural order and appear to move as a single coherent entity. In order to understand the complex motion of these systems, we study the Vicsek model of self-propelled particles (SPP) which is an important tool to investigate the behavior of collective motion of live organisms. This model reproduces the biological behavior patterns in the two-dimensional (2D) space. Within the framework of this model, the particles move with the same absolute velocity and interact locally in the zone of orientation by trying to align their direction with that of the neighbors. In this paper, we model the collective movement of SPP using an agent-based model which follows biologically motivated behavioral rules, by adding a second region called the attraction zone, where each particles move towards each other avoiding being isolated. Our main goal is to present a detailed numerical study on the effect of the zone of attraction on the kinetic phase transition of our system. In our study, the consideration of this zone seems to play an important role in the cohesion. Consequently, in the directional orientation, the zone that we added forms the compact particle group. In our simulation, we show clearly that the model proposed here can produce two collective behavior patterns: torus and dynamic parallel group. Implications of these findings are discussed.

Evolution of the Entropy of Dislocation Structures with Strain in Solid Solutions of Cu-0.5at.% Al

The study on the evolution of the dislocation structure (DS) parameters with strain of solid solutions of Cu-0.5 at.% Al at different test temperatures has been carried out. It has been shown that in substructures with a disordered type of DS (disorder), the disordered mixtures with non-disoriented cells, as well as mixtures of non-disoriented and disoriented cellular structures, the entropy density increases with strain. It has been shown that formation of the cellular substructure corresponds to a diffuse kinetic phase transition of the 1-st kind in the DS. A jump-like decrease in entropy accompanying this phase transition is associated with the annihilation of dislocations in cellular walls and formation of excess dislocation density.

EFFECTS OF AGENT'S REPULSION IN 2D FLOCKING MODELS

In nature many animal groups, such as fish schools or bird flocks, clearly display structural order and appear to move as a single coherent entity. In order to understand the complex behavior of these systems, many models have been proposed and tested so far. This paper deals with an extension of the Vicsek model, by including a second zone of repulsion, where each agent attempts to maintain a minimum distance from the others. The consideration of this zone in our study seems to play an important role during the travel of agents in the two-dimensional (2D) flocking models. Our numerical investigations show that depending on the basic ingredients such as repulsion radius (R1), effect of density of agents (ρ) and noise (η), our nonequilibrium system can undergo a kinetic phase transition from no transport to finite net transport. For different values of ρ, kinetic phase diagrams in the plane (η ,R1) are found. Implications of these findings are discussed.