Search results for " Computer Science"
showing 10 items of 3983 documents
Identification and characterisation of the dopamine receptor II from the cat flea Ctenocephalides felis (CfDopRII)
2006
International audience; G protein-coupled receptors (GPCRs) represent a protein family with a wide range of functions. Approximately 30% of human drug targets are GPCRs, illustrating their pharmaceutical relevance. In contrast, the knowledge about invertebrate GPCRs is limited and is mainly restricted to model organisms like Drosophila melanogaster and Caenorhabditis elegans. Especially in ectoparasites like ticks and fleas, only few GPCRs are characterised. From the cat flea Ctenocephalides felis, a relevant parasite of cats and dogs, no GPCRs are known so far. Thus, we performed a bioinformatic analysis of available insect GPCR sequences from the honeybee Apis mellifera, the mosquito Anop…
On Approximation of Entropy Solutions for One System of Nonlinear Hyperbolic Conservation Laws with Impulse Source Terms
2010
We study one class of nonlinear fluid dynamic models with impulse source terms. The model consists of a system of two hyperbolic conservation laws: a nonlinear conservation law for the goods density and a linear evolution equation for the processing rate. We consider the case when influx-rates in the second equation take the form of impulse functions. Using the vanishing viscosity method and the so-called principle of fictitious controls, we show that entropy solutions to the original Cauchy problem can be approximated by optimal solutions of special optimization problems.
Modeling Local Social Migrations: A Cellular Automata Approach
2015
In local social migrations, agents move from their initial location looking for a better local social environment. Social migrations processes do not change the number of social agents of a given type (i.e., the empirical distribution of the population) but their spatial location. Although cellular automata seems to appear as a natural approach to model of social migrations, the evolution of the configuration through a cellular automata might induce a new configuration wherein the number of agents of each type might be actually modified. This article provides a characterization of these cellular automata rules such that for any initial empirical distribution, the evolution of the configurat…
Social Simulation Based on Cellular Automata: Modeling Language Shifts
2011
Nowadays, language shifts (i.e., a community of speakers stops using their traditional language and speaks a new one in all communication settings) may produce a massive extinction of languages throughout the world. In this context, an important task for social sciences research should therefore be to achieve a deep comprehension of language shifts. However, modeling the social and behavioral variables that guide the social behavior of individuals and groups has traditionally been tricky in all the social sciences. In this situation, social simulation provides a tool for testing hypotheses and building models of social phenomena (see, for example, Gilbert, 1996; Gilbert & Toitzsch, 2005; an…
Analysis of neuronal networks in the visual system of the cat using statistical signals--simple and complex cells. Part II.
1978
Superimposing additively a two-dimensional noise process to deterministic input signals (bars) the neurons of area 17 show a class-specific reaction for the task of signal extraction. Moving both parts of the signals simultaneously and varying the signal to noise ratio (S/N) the simple cells achieve the same performance as resulted from the psychophysical experiment. Type I complex cells extract moving deterministic signals (i.e. bars) from the stationary noise, whereas in the answers of Type II complex cells the statistical parts of the signals predominate. Considering the different cell types each as a series of a linear and a nonlinear system one obtains the cell specific space-time freq…
System-theoretical analysis of the Clare Bishop Area in the cat
1980
The Clare Bishop Area (CBA) is a retinotopically organized cortical area in the cat brain connected to a great variety of visual areas in a very complex wax (Fig. 1). Experimental analysis is difficult because of the following aspects: 1. As the distance from the retina increases, the signal combinations necessary to analyse the system become more and more specific. 2. Feedback loops cannot be opened, so an unequivocal identification of CBA cell properties is impossible. 3. The nonlinear character seems to have a great influence on signal processing. To circumvent these problems, specific signal combinations leading to a separation of input subsystems have been developed (Hoffmann and v. Se…
On localization of moving objects in the visual system of cats.
1980
In cortical areas direction-specific receptive fields occur systematically. Direction specifity is based on unsymmetric coupling of neurons. Such a coupling allows an exact localization of moved stimuli. For this task, the asymmetry in the time domain is compensated for by a spatial asymmetry.
Sensor Calibration and Registration for Mobile Manipulators
2016
International audience; —This paper describes the methods used to register a mobile manipulator to a workstation to perform assembly tasks. The nonlinear, least square model of the system is formulated and Ceres Solver is used to compute the position of the robot arm relative to the mobile base. The use of non-contact fiducials to test the accuracy and repeatability of the mobile manipulator positioning in the context of an assembly operation is also discussed. Using mathematical methods and indirect measurements it is possible to compute the offset between physical components of the system where direct measurement is not feasible.
Adding symbolic information to picture models: definitions and properties
2005
AbstractIn the paper we propose extensions of some picture models, such as colored, drawn and pixel pictures. Such extensions are conceived by observing that a picture may embed more information than the shape, such as colors, labels, etc., which can be represented by a symbol from an alphabet and can be associated to segments, points or pixels. New interesting issues derived from the introduction of symbols will be investigated together with some complexity and decidability questions for the proposed extensions.
Qui a peur du changement climatique?
2019
ABSTRACT.The French "Grand Débat National" (Great National Debate) was animportant political event in 2019. Using the online proposals collected during thisconsultation, we propose a representation of the feeling of the impact of climate changeamong the contributors to the "Grand Débat National" in Metropolitan France. Weanalyze the causes of this feeling, through a supervised analysis of the contributions(via the Great Annotation) and we show the complementary interest of an unsuper-vised analysis (by extracting keywords). We show the richness of the data set that constitutes the "Grand Débat National", and the analytical stakes around these data.We also point out some important limitation…