161 research outputs found
Special issue featuring selected papers from the International Workshop on Bio-Inspired Robots (Nantes, France, 6-8 April 2011)
No full textsj-pdf-1-mav-10.1177_17568293221148380 - Supplemental material for Indoor and outdoor in-flight odometry based solely on optic flows with oscillatory trajectories
No full textSupplemental material, sj-pdf-1-mav-10.1177_17568293221148380 for Indoor and outdoor in-flight odometry based solely on optic flows with oscillatory trajectories by L Bergantin, C Coquet, J Dumon, A Negre, T Raharijaona, N Marchand and F Ruffier in International Journal of Micro Air Vehicles</p
A biphasic navigational strategy in loggerhead sea turtles
No full textThe homing journeys of nine loggerhead turtles translocated from their nesting beach to offshore release sites, were reconstructed through Argos and GPS telemetry while their water-related orientation was simultaneously recorded at high temporal resolution by multi-sensor data loggers featuring a three-axis magnetic sensor. All turtles managed to return to the nesting beach area, although with indirect routes encompassing an initial straight leg not precisely oriented towards home, and a successive homebound segment carried out along the coast. Logger data revealed that, after an initial period of disorientation, turtles were able to precisely maintain a consistent direction for several hours while moving in the open sea, even during night-time. Their water-related headings were in accordance with the orientation of the resulting route, showing little or no effect of current drift. This study reveals a biphasic homing strategy of displaced turtles involving an initial orientation weakly related to home and a successive shift to coastal navigation, which is in line with the modern conceptual framework of animal migratory navigation as deriving from sequential mechanisms acting at different spatial scales
Behaviour of buried pipelines subjected to external loading.
No full textThe research presented in this Thesis was carried out at the University of Sheffield under
the supervision of Dr I. C. Pyrah and Dr W. F. Anderson, and Mr G. Leach at British Gas
Engineering Research Station (ERS). The research was financially supported by a British
Gas Research Scholarship and by the Overseas Research Students Awards Scheme.
The Author would like to express his sincere gratitude to his supervisors for their invaluable
help, guidance and encouragement during the development of the research.
The Author is also grateful to Dr S. R. Mi for his interest and assistance throughout the
research. Special thanks also go to Dr S. J. Wheeler for his supervision during the first year
of the research and sound advice in the initial stage of the work.
The Author would like to express his gratitude to all members of the geotechnics group at
the University of Sheffield for the useful discussions and comments. Special thanks and
appreciation are extended to the staff at the ERS, particularly Mr E. Middleton for
providing the data of the field tests and constructive comments.
The laboratory tests were performed at ERS Soils Laboratory for which the Author is
thankful to the laboratory staff. The Author must also thank British Gas for providing the
computer hardware and software for performing the numerical analyses, and the printing
facilities to produce the Thesis. Thanks also go to Mr D. Reay and Mr B. Bellwood at the
Gas Research Centre of British Gas for ensuring continuous financial support throughout
the award period.
Finally, the Author wishes to thank his family and friends for their endless support and
encouragement throughout the period of study in the UK. Without them, this Thesis may
never have been completed
Code and data for the article "Accommodating unobservability to control flight attitude with optic flow"
No full textThis dataset contains the MATLAB code and experimental data for reproducing the observability analysis, simulation experiments, and plotting of robotic results for the article:
“Accommodating unobservability to control flight attitude with optic flow”, by G.C.H.E. de Croon, J.J.G. Dupeyroux, C. De Wagter, A. Chatterjee, D.A. Olejnik, F. Ruffier.
The dataset contains the logged flight data from quadrotor experiments (with a Parrot Bebop 2) and flapping wing robot experiments (with a Flapper Drone), as performed for the paper mentioned above.
Moreover, it contains the post-processed data (positions, pitch attitudes, as extracted with computer vision scripts from the images captured in the experimental setup) from the honeybee experiments performed in the article: Portelli, G., Ruffier, F., Roubieu, F. L., & Franceschini, N. (2011). Honeybees' speed depends on dorsal as well as lateral, ventral and frontal optic flows. PloS one, 6(5), e19486. This data has been re-analyzed in the light of the proposed new theory on estimating attitude with the help of optic flow.
The dataset contains a README document that further explains how to reproduce the results with the MATLAB code.
</p
From bees’ surface following to lunar landing
No full textInternational audienceTo better grasp the visuomotor control system underlying insects’ height and speed control (Srinivasan et al. 1996, Portelli et al. 2010a), we attempted to interfere with this system by producing a major perturbation on the free flying insect and observing the effect of thisperturbation. Honeybees were trained to fly along a high-roofed tunnel, part of which was equipped with a moving floor. The bees followed the stationary part of the floor at a given height. On encountering the moving part of the floor, which moved in the same direction as their flight, honeybees descended and flew at a lower height (See Fig. 1 E-F). In so doing, bees gradually restored their ventral optic flow (OF) to a similar optic flow value to that they had perceived when flying over the stationary part of the floor. OF restoration therefore relied on lowering the groundheight rather than increasing the groundspeed (Portelli, Ruffier, Franceschini 2010b).This result can be accounted for by a control system called an optic flow regulator, that is, a feedback control system based on an OF sensor, which strives to maintain the ventrally perceived OF at a constant set point by adjusting the vertical lift (See Fig. 1 A-D) (Ruffier, Franceschini 2005;Franceschini, Ruffier, Serres 2007). This visuo-motor control scheme may not only explain how honeybees land at a constant descent angle (Srinivasan et al. 2000) but also how they navigate safely along surfaces on the sole basis of OF measurements, without any need to measure either their speed or their distance from the ground, the ceiling or the surrounding walls (Serres et al. 2008, Portelli et al. 2010a), that is, without relying on any of the conventional avionic sensors such as velocimeters or rangefinders. Results obtained in neurophysiological, behavioural, and biorobotic studies on insect flight control were used to safely land a spacecraft on the Moon in a simulated environment. The optic flowregulator for automatic landing was tested in a realistic simulated Lunar environment (Valette et al. 2010). Visual information was provided using the ESA’s PANGU software program and used to regulate the optic flow sensed during the descent of a 2-DOF spacecraft. The results of thesimulation showed that a single 2-pixel optic flow sensor coupled to an optic flow regulator was able to robustly control the autonomous descent of the simulated lunar lander (See Fig. 2). “Low gate” located approximately 10 m above the ground was reached with reduced vertical andhorizontal speeds of 4m/s and 5m/s, respectively. It was also established that optic flow sensing methods can be used successfully to cope with temporary sensor blinding and poor lighting conditions (Valette et al. 2010), as typically occurs at the Moon south pole that the 2018 Next ESAmission is planning to explore
From bees’ surface following to lunar landing
No full textInternational audienceTo better grasp the visuomotor control system underlying insects’ height and speed control (Srinivasan et al. 1996, Portelli et al. 2010a), we attempted to interfere with this system by producing a major perturbation on the free flying insect and observing the effect of thisperturbation. Honeybees were trained to fly along a high-roofed tunnel, part of which was equipped with a moving floor. The bees followed the stationary part of the floor at a given height. On encountering the moving part of the floor, which moved in the same direction as their flight, honeybees descended and flew at a lower height (See Fig. 1 E-F). In so doing, bees gradually restored their ventral optic flow (OF) to a similar optic flow value to that they had perceived when flying over the stationary part of the floor. OF restoration therefore relied on lowering the groundheight rather than increasing the groundspeed (Portelli, Ruffier, Franceschini 2010b).This result can be accounted for by a control system called an optic flow regulator, that is, a feedback control system based on an OF sensor, which strives to maintain the ventrally perceived OF at a constant set point by adjusting the vertical lift (See Fig. 1 A-D) (Ruffier, Franceschini 2005;Franceschini, Ruffier, Serres 2007). This visuo-motor control scheme may not only explain how honeybees land at a constant descent angle (Srinivasan et al. 2000) but also how they navigate safely along surfaces on the sole basis of OF measurements, without any need to measure either their speed or their distance from the ground, the ceiling or the surrounding walls (Serres et al. 2008, Portelli et al. 2010a), that is, without relying on any of the conventional avionic sensors such as velocimeters or rangefinders. Results obtained in neurophysiological, behavioural, and biorobotic studies on insect flight control were used to safely land a spacecraft on the Moon in a simulated environment. The optic flowregulator for automatic landing was tested in a realistic simulated Lunar environment (Valette et al. 2010). Visual information was provided using the ESA’s PANGU software program and used to regulate the optic flow sensed during the descent of a 2-DOF spacecraft. The results of thesimulation showed that a single 2-pixel optic flow sensor coupled to an optic flow regulator was able to robustly control the autonomous descent of the simulated lunar lander (See Fig. 2). “Low gate” located approximately 10 m above the ground was reached with reduced vertical andhorizontal speeds of 4m/s and 5m/s, respectively. It was also established that optic flow sensing methods can be used successfully to cope with temporary sensor blinding and poor lighting conditions (Valette et al. 2010), as typically occurs at the Moon south pole that the 2018 Next ESAmission is planning to explore
Le travail des dominations - De l’emprise aux résistances
No full textNous vous signalons la parution chez Octarès d'un ouvrage coordonné par G. Flocco, F. Mougeot et C. Ruffier Le sommaire Préface Jean-Claude Barbier, Jean-Pierre Durand et Salvatore Maugeri Introduction générale Gaëtan Flocco, Frédéric Mougeot et Clément Ruffier Des pensées fondatrices Le consentement à la domination L’autonomie et les résistances des dominés La dimension expressive du travail et ses résistances Les travailleurs sous la férule du capitalisme financiarisé La domi..
Um modelo de realização de baixo contínuo para trechos da ópera Ariane et Bacchus, de Marin Marais (1696), segundo as regras do Nouveau traité de l’accompagnement de Saint-Lambert (1707)
No full textOrientador: Profª. Drª. Silvana Ruffier ScarinciMonografia (bacharelado) - Universidade Federal do Paraná, Setor de Setor de Artes, Comunicação e Design, Curso de Graduação em MúsicaInclui referênciasResumo : O presente trabalho propõe uma discussão sobre a técnica de baixo contínuo, baseando-se no Nouveau traité de l’accompagnement de Saint-Lambert, publicado no ano de 1707. As regras apresentadas por Saint-Lambert foram aplicadas a trechos selecionados da ópera Ariane et Bacchus, de Marin Marais, do ano de 1696. A aplicação das regras de Saint-Lambert sobre os trechos da ópera gerou, como produto final, uma sugestão de realização do acompanhamento destas partes ao cravo. O tratado de Saint-Lambert e o conteúdo de suas regras serão disponibilizados pela primeira vez para público lusófono pela tradução do tratado, que está incluída como anexo desta monografia. Os conceitos e normas apresentados pelo autor poderão, na posteridade, ser aplicados às demais partes da ópera e outras obras de semelhante contexto históricoAbstract : The current monograph presents a discussion about the thoroughbass technique, based on SaintLambert’s Nouveau traité de l’accompagnement, published in 1707. The rules presented by Saint-Lambert were applied upon selected excerpts of the opera Ariane et Bacchus, by Marin Marais, from 1696. The application of Saint-Lambert’s rules upon excerpts of the opera has generated, as a final product, a suggestion of thoroughbass realization for these excerpts to be played on the harpsichord. Saint-Lambert’s treatise and the content of its rules will be made available for the first time for the Lusophone public by the treatise’s translation, which is included as an attachment of this monograph. The concepts and rules presented by the author could, in posterity, be applied to the remaining excerpts of the opera and to other works with a similar historical backgroun
Exploraciones y restauraciones en Palenque, 1968-1970.. Anales del Instituto Nacional de Antropología e Historia. Num. 51 Tomo III (1970-1971) Séptima Época (1967-1976)
No full textEn la presente temporada se continuaron los trabajos emprendidos en 1967 que, en general, fueron para salvar los estucos que se encuentran sobre los pilares de El Palacio y dentro de la cripta del Templo de las Inscripciones. En El Palacio, era cuestión de consolidar los techos que, con poca excepción, se encontraban en muy malas condiciones. Ya al finalizar la temporada, todos fueron reparados. En el Templo de las Inscripciones, después de muchas dificultades debidas a los constantes derrumbes, se pudo levantar el primer cuerpo de la pirámide en la sección al oeste de la escalera central, cosa que no se pudo hacer en 1967. Ya con esto, se podrán reconstruir los demás cuerpos hasta la plataforma superior. Mientras no se termine esta obra, siempre habrán filtraciones dentro de la cripta. Por desgracia, el intento de sacar el agua que se acumula en el piso de la cámara, por medio de una bomba, no dio resultado por la razón expuesta; sin embargo, tenemos la esperanza de que los 2 pozos de absorción ayudarán a eliminar en parte esta agua. Se continuaron los trabajos en la escalera oeste de El Palacio y se llegó al extremo norte de ella, y al prolongar en esta misma dirección, se llegó al ángulo noroeste de la plataforma, apareciendo, durante el proceso, una subestructura con tableros. En el sur no se pudo hacer lo mismo en vista de la excesiva cantidad de escombro y por un cambio radical en el tipo de edificio que dificultaba el progreso de la exploración. Los trabajos de consolidación en el Edificio XII fueron indispensables, ya que el templo peligraba derrumbarse en cualquier momento. Aprovechando la presencia de trabajadores en el lugar, se realizó una exploración debajo del mismo, hallándose otro edificio más antiguo en buenas condiciones; sin embargo, no se encontraron tumbas ni ofrendas. Sin duda el resultado más importante de la temporada fue la exploración del Edificio XIV situado cerca y al norte del Templo de la Cruz Foliada. Apareció un pequeño basamento de 2 cuerpos en magníficas condiciones y, sobre la plataforma superior, los restos de un santuario decorado con bajorrelieves de estuco; debajo del piso se halló una ofrenda bastante pobre en relación con la calidad de la estructura. En la parte posterior se encontraron numerosos fragmentos de las lápidas que, por lo general, se encuentran colocadas en el fondo de los templos superiores. Fueron reparadas; pero, mientras no se haga la restauración total del edificio, no se les podrá colocar en su sitio original. Mientras tanto, se encuentran empotradas en uno de los muros del campamento de la zona arqueológica para su mayor seguridad. No hay duda que es uno de los mejores ejemplos del alto grado de perfección que alcanzaron los escultores palencanos. En lo relacionado con la interpretación de los glifos, poco se ha podido decir porque el autor no es un especialista en la materia. Según Thompson se trata de una fecha relacionada con cálculos cosmogónicos que retroceden un mínimo de 300 mil años en el pasado. Desde luego, en la zona maya existen cálculos que no sólo llegan a los cientos de miles de años sino hasta millones de años hacia atrás; pero son escasas. En la inmensa mayoría de los casos se trata de fechas contemporáneas como, por ejemplo, la dedicación del monumento o la coronación de un dignatario. La fecha que está en E-1 y F-1 que ha sido interpretada como 9.10.15.7.10. 13 Oc 18 Uo, o sea 649 dC, sí parece indicar un suceso histórico, ya que está relacionado directamente con el personaje central que ocupa el sitio de honor en la lápida. En vista de esto, se ha designado el Edificio XIV como el Templo del Gran Sacerdote. Que Thompson tenga o no la razón, lo dejo en manos de los expertos en la epigrafía maya. La presencia de los conservadores del Departamento de Catálogo y Restauración fue de gran utilidad para limpiar y consolidar numerosos estucos y lápidas, entre otras, las de los templos del Sol y de La Cruz Foliada que estaban tan cubiertas de musgos que era imposible ver sus preciosos relieves. Aunque en lo general se ha adelantado mucho, se necesitarán por lo menos dos temporadas más para terminar las obras en el Templo de las Inscripciones, para que la cripta quede a salvo de las filtraciones que tanto daño están causando a los estucos en su interior
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