EFFECTS OF AGENT'S REPULSION IN 2D FLOCKING MODELS

2011 ◽  
Vol 22 (07) ◽  
pp. 661-668 ◽  
Author(s):  
NAJEM MOUSSA ◽  
ILIASS TARRAS ◽  
M'HAMMED MAZROUI ◽  
YAHYA BOUGHALEB
Keyword(s):  
Phase Transition ◽  
Phase Diagrams ◽  
Minimum Distance ◽  
Complex Behavior ◽  
Two Dimensional ◽  
Vicsek Model ◽  
Fish Schools ◽  
Numerical Investigations ◽  
Structural Order ◽  
Kinetic Phase Transition

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.

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

2016 ◽  
Vol 30 (04) ◽  
pp. 1650002 ◽  
Author(s):  
Tarras Iliass ◽  
Dorilson Cambui
Keyword(s):  
Collective Motion ◽  
Numerical Study ◽  
Biological Behavior ◽  
Behavior Patterns ◽  
Vicsek Model ◽  
Agent Based ◽  
Fish Schools ◽  
Behavioral Rules ◽  
Parallel Group ◽  
Kinetic Phase Transition

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.

Liquid–liquid phase transition in quasi-two-dimensional supercooled silicon

2014 ◽  
Vol 16 (33) ◽  
pp. 18023-18028 ◽  
Author(s):  
K. Zhang ◽  
H. Li ◽  
Y. Y. Jiang
Keyword(s):  
Phase Transition ◽  
Liquid Phase ◽  
Liquid Silicon ◽  
Two Dimensional ◽  
Liquid Phase Transition ◽  
Structural Order

Anomalies of the local structural order in quasi-two-dimensional liquid silicon upon cooling are investigated.

Temperature Effect on the Two-Dimensional Phase Transition Kinetics of Adenine Adsorbed at the Hg Electrode/Aqueous Solution Interface

2003 ◽  
Vol 68 (8) ◽  
pp. 1407-1419 ◽  
Author(s):  
Claudio Fontanesi ◽  
Roberto Andreoli ◽  
Luca Benedetti ◽  
Roberto Giovanardi ◽  
Paolo Ferrarini
Keyword(s):  
Phase Transition ◽  
Aqueous Solution ◽  
Phase Change ◽  
Temperature Effect ◽  
Transition Rate ◽  
Effect Of Temperature ◽  
Two Dimensional ◽  
Solution Interface ◽  
Phase Transition Kinetics ◽  
Kinetics Of

The kinetics of the liquid-like → solid-like 2D phase transition of adenine adsorbed at the Hg/aqueous solution interface is studied. Attention is focused on the effect of temperature on the rate of phase change; an increase in temperature is found to cause a decrease of transition rate.

scholarly journals Pricing and Return Policies in a Competitive Market: A Consumer-Valuation Based Analysis with Valuation Uncertainties

2021 ◽  
Vol 13 (3) ◽  
pp. 1432
Author(s):  
Huifang Jiao ◽  
Xuan Wang ◽  
Chi To Ng ◽  
Lijun Ma
Keyword(s):  
Competitive Market ◽  
Two Dimensional ◽  
Competitive Markets ◽  
Return Policies ◽  
Numerical Investigations ◽  
Return Policy ◽  
Consumer Valuation ◽  
Competition Models ◽  
Monopoly Market ◽  
Duopoly Market

In this study, we develop a series of consumer-valuation-based models to investigate the pricing and return policies of the sellers in a competitive e-commerce market. Differing from the competition models in literature, a novel two-dimensional valuation structure is built, which considers the valuations of a consumer on two products and the valuation differentiation of all consumers on each product. We consider both monopoly and duopoly (competitive) markets. In each market, two models are respectively developed, one with and one without the return policies. We derive the solutions for the four models, and conduct some analytical and numerical investigations. The results show that return policy with a partial refund is always chosen by the sellers in both monopoly and duopoly markets. Return policy benefits the seller in a monopoly market, but may not benefit the sellers in a duopoly market. In the duopoly models, one seller can be considered as a monopoly seller who meets a new competitor. Our results show that the monopoly seller will reduce its price by no more than 20% when there comes a competitor, and, counter-intuitively, it will meanwhile adopt a severer return policy to the consumers.

scholarly journals Quantum effects on the BKT phase transition of two-dimensional Josephson arrays

2000 ◽  
Vol 61 (17) ◽  
pp. 11289-11292 ◽  
Author(s):  
Alessandro Cuccoli ◽  
Andrea Fubini ◽  
Valerio Tognetti ◽  
Ruggero Vaia
Keyword(s):  
Phase Transition ◽  
Quantum Effects ◽  
Two Dimensional ◽  
Josephson Arrays ◽  
Bkt Phase Transition

Numerical Analysis of Two-Phase Pipe Flow of Liquid Helium Using Multi-Fluid Model

2001 ◽  
Vol 123 (4) ◽  
pp. 811-818 ◽  
Author(s):  
Jun Ishimoto ◽  
Mamoru Oike ◽  
Kenjiro Kamijo
Keyword(s):  
Phase Transition ◽  
Gas Phase ◽  
Liquid Helium ◽  
Two Phase Flow ◽  
Fluid Model ◽  
Numerical Results ◽  
Phase Flow ◽  
Two Dimensional ◽  
Two Phase ◽  
Normal Fluid

The two-dimensional characteristics of the vapor-liquid two-phase flow of liquid helium in a pipe are numerically investigated to realize the further development and high performance of new cryogenic engineering applications. First, the governing equations of the two-phase flow of liquid helium based on the unsteady thermal nonequilibrium multi-fluid model are presented and several flow characteristics are numerically calculated, taking into account the effect of superfluidity. Based on the numerical results, the two-dimensional structure of the two-phase flow of liquid helium is shown in detail, and it is also found that the phase transition of the normal fluid to the superfluid and the generation of superfluid counterflow against normal fluid flow are conspicuous in the large gas phase volume fraction region where the liquid to gas phase change actively occurs. Furthermore, it is clarified that the mechanism of the He I to He II phase transition caused by the temperature decrease is due to the deprivation of latent heat for vaporization from the liquid phase. According to these theoretical results, the fundamental characteristics of the cryogenic two-phase flow are predicted. The numerical results obtained should contribute to the realization of advanced cryogenic industrial applications.

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