368 research outputs found
Adaptive Coordination and Aggregate Efficiency in Minority Games
No full textR. Cowan and N. Jonard (eds.
Fits and Misfits: Technological Matching and R&D Networks
No full textThis paper presents an economic model of R&D network formation through the creation of strategic alliances. Firms are randomly endowed with knowledge elements. They base their alliance decisions purely on the technological fit of potential partners, ignoring social capital considerations and indirect benefits on the network. This is sufficient to generate equilibrium networks with the small world properties of observed alliance networks, namely short pairwise distances and local clustering. The equilibrium networks are more clustered than "comparable" random graphs, while they have similar characteristic path length. Two extreme regimes of competition are examined, to show that while the competition has a quantitative effect on the equilibrium networks (density is lower with competition), the small world features of the equilibrium networks are preserved.network formation, small worlds, R&D networks, strategic alliances, business clusters
Radiative transfer modeling in structurally-complex stands: what aspects matter most?: Dataset
No full textThis repository is linked to the paper "Radiative transfer modeling in structurally-complex stands: what aspects matter most?" submitted to Annals of Forest Science and written by Frédéric ANDRÉ (corresponding author), Louis DE WERGIFOSSE, François DE COLIGNY, Nicolas BEUDEZ, Gauthier LIGOT, Vincent GAUTHRAY-GUYÉNET, Benoit COURBAUD and Mathieu JONARD.
The repository contains the three following files :
CalibrationResults.csv: Bayes factors and summary statistics of parameter estimates for each calibration run
ParameterPosteriorDistributions.csv: median values and 90% credible intervals for the parameter posterior distributions
StatisticalComparison.csv: statistics (Fractional bias, Root mean square error, Paired Student test, Pearson correlation coefficient, Parameters of the Deming regression between observed and predicted values) used to compare the 'Best model configurations'
For more information concerning this repository or the study, please do not hesitate to contact Frédéric ANDRÉ ([email protected]) or Mathieu JONARD ([email protected])
Compact convex sets in 2-dimensional asymmetric normed lattices
No full text[EN] In this note, we study the geometric structure of compact convex sets in 2-dimensional asymmetric normed lattices. We prove that every q-compact convex set is strongly q-compact and we give a complete geometric description of the compact convex set with non empty interior in (R-2, q), where q is an asymmetric lattice norm.The first author has been supported by CONACYT (Mexico) under Grant 204028. The second author has been supported by the Ministerio de Economia y Competitividad (Spain) under Grant MTM2012-36740-C02-02.Jonard-Perez, N.; Sánchez Pérez, EA. (2016). Compact convex sets in 2-dimensional asymmetric normed lattices. Quaestiones Mathematicae. 39(1):73-82. https://doi.org/10.2989/16073606.2015.1023864S738239
Local compactness in right bounded asymmetric normed spaces
No full text[EN] We characterize the ¿nite dimensional asymmetric normed spaces which are right bounded and the relation of this property with the natural compactness properties of the unit ball, such as compactness and strong compactness. In contrast with some results found in the ex-isting literature, we show that not all right bounded asymmetric norms have compact closed balls. We also prove that there are ¿nite dimen-sional asymmetric normed spaces that satisfy that the closed unit ball is compact, but not strongly compact, closing in this way an open ques-tion on the topology of ¿nite dimensional asymmetric normed spaces. In the positive direction, we will prove that a ¿nite dimensional asym-metric normed space is strongly locally compact if and only if it is right bounded.The first author has been supported by Conacyt grant 252849 (Mexico) and by PAPIIT grant IA104816 (UNAM, Mexico). The second author has been supported by Ministerio de Economia y Competitividad (Spain) (project MTM2016-77054-C2-1-P)Jonard Pérez, N.; Sánchez Pérez, EA. (2018). Local compactness in right bounded asymmetric normed spaces. Quaestiones Mathematicae. 41(4):549-563. https://doi.org/10.2989/16073606.2017.1391351S54956341
Primer reporte de Dendropsophus columbianus (Boettger, 1892) (Anura: Hylidae) para el departamento del Chocó, Colombia
No full textObjective: Document the rst record of the well Dendropsophus columbianus frog in low montane rain forest (bp-MB), in the department of Chocó, Colombia. Materials and Methods: During a rapid assessment of the anuran community in the municipality of Carmen de Atrato (5°53’42.2’’N, 76°08’38.9’’W, 1763 msnm), through the method of searching for visual encounters (VES, for its acronym in English), a specimen of D. Columbianus, was detected in an area with strong agricultural and livestock pressure. Results: A female of D. columbianus was observed on a patch of vegetation surrounding an abandoned pond. The indivi- dual was collected, determined and deposited in the Scienti c Collection of Zoological Reference of Chocó-Herpetology. Conclusion: This record becomes the rst for the department of Chocó. Objetivo: Documentar el primer registro de la rana de pozo Dendropsophus columbianus, en bosque pluvial montano bajo (bp-MB), en el departamento del Chocó, Colombia. Materiales y métodos: Durante una evaluación rápida de la comunidad de anuros, en el municipio de El Carmen de Atrato (5°53’42.2’’N, 76°08’38.9’’W, 1763 msnm), mediante el método de búsqueda por encuentros visuales (VES, por sus siglas en inglés), se detectó un ejemplar de D. columbianus, en un área con una fuerte presión agrícola y ganadera. Resultados: Se observó una hembra de D. columbianus sobre un parche de vegetación que rodeaba un estanque abandonado. El individuo fue colectado, determinado y depositado en la Colección Cientí ca de Referencia Zoológica del Chocó-Herpetología. Conclusión: Este registro se convierte en el primero para el departamento del Chocó.
In-flight measurement of kite deformations with inertial sensors
No full textThe control and design of kites for airborne wind energy requires an extensive understanding of kite dynamics. While these have been thoroughly analyzed with fluid-structure interaction models, very little experimental data exists to validate them. Specifically, most experiments on kites so far have not obtained local measurements that can be compared to these models. Measuring deformations of a kite during flight can provide a basis to validate computational models and additional insights on its dynamics. In this study, a kite shape measurement method using inertial measurement units is developed. In parallel, a stereo-photogrammetry technique is implemented in the software Blender and used to validate the new method.The inertial sensors are placed along the leading edge of a leading-edge inflatable kite to obtain the orientations of its tubular elements. The misalignment between the sensors and the leading edge elements is determined using a short photogrammetric measurement of the kite shape. With the corrected orientations, the shape of the kite is reconstituted using an algorithm that uses a reference shape of the leading edge and a basic structural model. Both measurement methods are used on a small-scale setup with a kite-surfing kite. Photogrammetry and the inertial shape measurement are compared and show a moderate agreement, but the two measurements could not properly aligned, making the comparison unreliable. Nonetheless, the inertial measurement is consistent with the turn rate, according to theory, and the new method is considered partially validated.The inertial shape measurement is used to establish a link between the tip deflection and three flight parameters: the apparent wind speed, the turn rate, and the roll angle of the kite. The data is fitted to a function with physically relevant parameters that describe the sensitivity of the deflection to the different variables. The fitted function accurately follows the main trend of the data, but many outlier points cause a significant error, due to the poor quality of the measured data. This analysis still shows a possibility of empirically developing a simple description of kite deformations from shape measurements.<br/
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