Search results for "Modeling"
showing 10 items of 4489 documents
Opinion dynamics and stubbornness through mean-field games
2013
This paper provides a mean field game theoretic interpretation of opinion dynamics and stubbornness. The model describes a crowd-seeking homogeneous population of agents, under the influence of one stubborn agent. The game takes on the form of two partial differential equations, the Hamilton-Jacobi-Bellman equation and the Kolmogorov-Fokker-Planck equation for the individual optimal response and the population evolution, respectively. For the game of interest, we establish a mean field equilibrium where all agents reach epsilon-consensus in a neighborhood of the stubborn agent's opinion.
FAST OSCILLATING MIGRATIONS IN A PREDATOR-PREY MODEL
1996
The aim of this paper is to give a method which permits us to describe how individual properties can emerge at the population level, in population dynamics. We consider interacting populations. In order to take into account the spatial or behavioral heterogeneity, we subdivide each population into subpopulations. A given subpopulation corresponds to those individuals having the same behavior and who are in a homogeneous environment. Furthermore, we assume that the migration process is faster than the growth and interaction processes. Therefore, we must study models with many variables coupled together into large scaled differential systems. Firstly, our method permits us to reduce these co…
Validation of the F-DBQ: A short (and accurate) risky driving behavior questionnaire for long-haul professional drivers
2021
Abstract Although the Driving Behavior Questionnaire (DBQ) remains the most known tool for assessing risky road behaviors among motor vehicle drivers, recent studies have raised several concerns on the specificity of both driving task conditions and behavioral repertory of certain segments of the driving population. Among them, long-haul (cargo) professional drivers constitute one of the “intensive driving” groups for which the existing adapted behavioral research tools are still very scarce. Purpose The aim of the present study was to test and validate the F-DBQ (or “Freight Driving Behavior Questionnaire”), a short version of the DBQ adapted to the occupational driving conditions and typi…
Autism spectrum disorders and anxiety: measurement and treatment
2021
Abstract Autism spectrum disorders (ASDs) are a group of neurodevelopmental disorders that have, in common, deficits in communication and social interaction and present repetitive behaviors and restricted interests. There is a great variability of symptoms associated with ASD. Among them, anxiety disorders are perhaps one of the most frequent and most developmentally disruptive in children, youths, and adults, which generate alterations in family life also. The treatments based on cognitive–behavioral therapy (CBT) have the highest scientific evidence. In a population with ASD, both program adaptations and specific programs have been developed. Due to its characteristics, the most studied p…
ON THE EXISTENCE OF LIMIT CYCLES IN OPINION FORMATION PROCESSES UNDER TIME PERIODIC INFLUENCE OF PERSUADERS
2008
This paper concerns a model of opinion formation in a population of interacting individuals under the influence of external leaders or persuaders, which act in a time periodic fashion. The model is formulated within a general framework inspired to a discrete generalized kinetic approach, which has been developed in Ref. 6. It is expressed by a system of non-autonomous nonlinear ordinary differential equations. The dynamics of such a system is investigated and the existence of a globally asymptotically stable periodic solution is analytically proved in three example cases, each one corresponding to a different quantitative choice of the actions of the persuaders. Equivalently, in three part…
Generating a Located Synthetic Population of Individuals, Households, and Dwellings
2017
Some of the new approaches in urban modeling, such as multi-agent systems (MAS) or activity-based models (ABM), require inputs in the form of disaggregated individual data. But for privacy protection reasons, such data is seldom available at this level. One way to get around this obstacle is to generate a synthetic population. This paper presents a method for generating a population from fully aggregated socio-demographic and geographic data. Based on French examples, this method can be reproduced anywhere in the country providing a relevant linkage between the characteristics of agents and those of urban spaces. The proposed method is subdivided into two steps. First, a population of agent…
An individual based model for the conservation of the endangered Large Blue Butterfly, Maculinea arion (Lepidoptera: Lycaenidae)
2002
Abstract European populations of the Large Blue Butterfly Maculinea arion have experienced severe declines during the 20th century, especially in the northern part of the species’ range. This endangered lycaenid butterfly needs two resources for development: flower buds of specific plants ( Thymus spp., Origanum vulgare ), on which young caterpillars briefly feed, and red ants of the genus Myrmica , whose nests support caterpillars during a prolonged final instar. In order to improve understanding of those mechanisms that are most influential to population dynamics of the butterfly, we developed a stochastic population model. This individual based model implements three main biological comp…
Modelling drift of pelagic offspring: the importance of egg surveys in providing a realistic model initialization
2015
Abstract Having valid information about the location and dynamics of biological processes is important for coastal management. In this context modelling, the pelagic drift of early life stages has been shown to be an important tool for understanding the spatial scale of population dynamics in marine systems. Often simulated particles are released in hypothetical quantities at assumed spawning grounds with no or few field data to guide the model parametrization. In this study, we combine high-resolution field data and state-of-the-art oceanographic modelling and use a probabilistic approach to construct kernel density distributions of the dispersal of pelagic fish eggs. Specifically, the pot…
Mathematical modelling of social obesity epidemic in the region of Valencia, Spain
2010
In this article, we analyse the incidence of excess weight in 24- to 65-year-old residents in the region of Valencia, Spain, and predict its behaviour in the coming years. In addition, we present some possible strategies to prevent the spread of the obesity epidemic. We use classical logistic regression analysis to find out that a sedentary lifestyle and unhealthy nutritional habits are the most important causes of obesity in the 24- to 65-year-old population in Valencia. We propose a new mathematical model of epidemiological type to predict the incidence of excess weight in this population in the coming years. Based on the mathematical model sensitivity analysis, some possible general stra…