9,352 research outputs found
Phase Transitions in a Kinetic Flocking Model of Cucker-Smale Type
We consider a collective behavior model in which individuals try to imitate each others' velocity and have a preferred speed. We show that a phase change phenomenon takes place as diffusion decreases, bringing the system from a âdisorderedâ to an âorderedâ state. This effect is related to recently noticed phenomena for the diffusive Vicsek model. We also carry out numerical simulations of the system and give further details on the phase transition
Trajectories of functioning and mental health: determinants in general population
Tesis doctoral inĂ©dita leĂda en la Universidad AutĂłnoma de Madrid, Facultad de Medicina, Departamento de PsiquiatrĂa. Fecha de lectura: 17-10-201
Particle interactions mediated by dynamical networks: assessment of macroscopic descriptions
We provide a numerical study of the macroscopic model of [3] derived from an
agent-based model for a system of particles interacting through a dynamical
network of links. Assuming that the network remodelling process is very fast,
the macroscopic model takes the form of a single aggregation diffusion equation
for the density of particles. The theoretical study of the macroscopic model
gives precise criteria for the phase transitions of the steady states, and in
the 1-dimensional case, we show numerically that the stationary solutions of
the microscopic model undergo the same phase transitions and bifurcation types
as the macroscopic model. In the 2-dimensional case, we show that the numerical
simulations of the macroscopic model are in excellent agreement with the
predicted theoretical values. This study provides a partial validation of the
formal derivation of the macroscopic model from a microscopic formulation and
shows that the former is a consistent approximation of an underlying particle
dynamics, making it a powerful tool for the modelling of dynamical networks at
a large scale
The CIAO multiparadigm compiler and system: A progress report
Abstract is not available
Womenâs disengagement from legal proceedings for intimate partner violence in southern Spain: Variables related to legal proceedings
This article studies the relationship between a set of variables related to the
legal process and womenâs disengagement from legal proceedings against
their (ex)partners in Southern Spain. A total of 345 women answered a
questionnaire. Results evidenced that request for a protection order (PO),
granting such PO, imprisonment of the offender, and womenâs perception of
who decided during the process were significantly related to disengagement
(medium effect size). In addition, a logistic regression model was developed
to predict disengagement with two variables: granting a PO and womenâs
perception of who decided. Results are interpreted in terms of the necessity
that the judicial system gives support, protects, and provides women with
opportunities to participate in the recovery process.Junta de AndalucĂa 1071/0453Ministerio de EducaciĂłn, Cultura y Deporte (España) FPU15/0037
Computation of the optimal relative pose between overlapping grid maps through discrepancy minimization
Grid maps are a common environment representation in mobile robotics. Many Simultaneous Localization and Mapping (SLAM) solutions divide the global map into submaps, forming some kind of graph or tree to represent the structure of the environment, while the metric details are captured in the submaps. This work presents a novel algorithm that is able to compute a physically feasible relative pose between two overlapping grid maps. Our algorithm can be used for correspondence search (data association), but also for integrating negative information in a unified way. This paper proposes a discrepancy measure between two overlapping grid maps and its application in a quasi Newton optimization algorithm, with the hypothesis that minimizing such discrepancy could provide useful information for SLAM. Experimental evidence is provided showing the high potential of the algorithm
Asymptotic L1-decay of solutions of the porous medium equation to self-similarity
We consider the ïŹow of gas in an N -dimensional porous medium with initial density v0 (x) â„ 0. The density v(x, t) then satisïŹes the nonlinear degenerate parabolic equation vt = âv m where m > 1 is a physical constant. Assuming that (1 + , t). We prove that the L1 -distance decays at a rate t 1/((N+2)mâN) . Moreover, if N = 1, we obtain an explicit time decay for the Lâ distance at a suboptimal rate. The method we use is based on recent results we obtained for the Fokker-Planck equation [2], [3]
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