Precision laser spectroscopy of the ground state hyperfine splitting of hydrogenlike ^209 Bi^82+

The first direct observation of a hyperfine splitting in the optical regime is reported. The wavelength of the M1 transition between the F = 4 and F = 5 hyperfine levels of the ground state of hydrogenlike ^209 Bi^82+ was measured to be \lamda_0 = 243.87(4) nm by detection of laser induced fluorescence at the heavy-ion storage ring ESR at GSI. In addition, the lifetime of the laser excited F = 5 sublevel was determined to be \tau_0 = 0.351(16) ms. The method can be applied to a number of other nuclei and should allow a novel test of QED corrections in the previously unexplored combination of strong magnetic and electric fields in highly charged ions.

Generalization over contrast and mirror reversal, but not figure-ground reversal, in an "edge-based

Baylis & Driver (Nature Neuroscience, 2001) have recently presented data on the response of neurons in macaque inferotemporal cortex (IT) to various stimulus transformations. They report that neurons can generalize over contrast and mirror reversal, but not over figure-ground reversal. This finding is taken to demonstrate that ``the selectivity of IT neurons is not determined simply by the distinctive contours in a display, contrary to simple edge-based models of shape recognition'', citing our recently presented model of object recognition in cortex (Riesenhuber & Poggio, Nature Neuroscience, 1999). In this memo, I show that the main effects of the experiment can be obtained by performing the appropriate simulations in our simple feedforward model. This suggests for IT cell tuning that the possible contributions of explicit edge assignment processes postulated in (Baylis & Driver, 2001) might be smaller than expected.

Estudi de l’eficiència aerodinàmica de vehicles pesants de transport de passatgers

Estudi de l’eficiència aerodinàmica de les carrosseries de vehicles pesants de cara a reduir el consum de combustible en autocars de llarg trajecte. L’estudi es basa en tres aspectes: validació del programa de simulació, estudi aerodinàmic de diferents carrosseries d’autocar de mercat i estudi aerodinàmic de diferents complements

Influència de l'ús del biodièsel en les emissions contaminants i en el consum de combustible en vehicles pesants

L’objecte d’aquest estudi consisteix en determinar la influència de l’ús del biodièsel en: 1.- Les variacions en comparació amb el combustible convencional (gasoil A) en les emissions de gasos i partícules contaminants en motors de vehicles pesants de transport de mercaderies. 2.- Les variacions en comparació amb el combustible convencional (gasoil A) en el nivell de so emès per motors de vehicles pesants de transport de mercaderies. 3.- Els canvis en el consum de combustible en vehicles pesants en comparació amb la utilització de gasoil A. 4.- Els problemes tècnics observats en motors de vehicles pesants de transport de mercaderies durant un període de funcionament elevat

Estudi de la influència del vent en l’estabilitat de vehicles pesants de transport de viatgers.

Investigacions recents revelen com l’acció del vent lateral és un efecte molt important en bona part dels accidents ocorreguts en vehicles pesants de transport per carretera. És per això que el perfil aerodinàmic del vehicle esdevé determinant en l’avaluació de les forces laterals que hi actuen. El present projecte té per objecte determinar les forces laterals que s’exerceixen en vehicles pesants de transport de passatgers degut a l’acció del vent i investigar-ne la seva perillositat. Per fer-ho s’utilitzen models numèrics de dinàmica de fluids i, per diferents velocitats del vehicle, es simulen vents amb diferent intensitat i direcció. D’aquí es determinen unes condicions de perillositat en funció, entre d’altres variables, de l’angle d’incidència del vent i de la seva velocitat

Aplicació de la tècnica d’ espectroscòpia d’ absorció atòmica de flama com a eina per al manteniment de vehicles

L’objectiu d’aquest projecte fi de carrera és en primer lloc, determinar les modificacions a realitzar en el laboratori de lubricants i combustibles de l’EPS per a la utilització de l’espectrofotòmetre d’absorció atòmica de flama; en segon lloc, posar a punt l’aparell establint els paràmetres i les condicions d’assaig idònies per a portar a terme les anàlisis de metalls de desgast presents en olis lubricants usats de motors de combustió interna. I finalment, establir un protocol de treball al laboratori i estudiar la viabilitat d’oferir el servei d’anàlisi de lubricants a empreses i particulars

A behavior-based scheme using reinforcement learning for autonomous underwater vehicles

This paper presents a hybrid behavior-based scheme using reinforcement learning for high-level control of autonomous underwater vehicles (AUVs). Two main features of the presented approach are hybrid behavior coordination and semi on-line neural-Q_learning (SONQL). Hybrid behavior coordination takes advantages of robustness and modularity in the competitive approach as well as efficient trajectories in the cooperative approach. SONQL, a new continuous approach of the Q_learning algorithm with a multilayer neural network is used to learn behavior state/action mapping online. Experimental results show the feasibility of the presented approach for AUVs

Model-based objects recognition in industrial environments for autonomous vehicles control

Behavior-based navigation of autonomous vehicles requires the recognition of the navigable areas and the potential obstacles. In this paper we describe a model-based objects recognition system which is part of an image interpretation system intended to assist the navigation of autonomous vehicles that operate in industrial environments. The recognition system integrates color, shape and texture information together with the location of the vanishing point. The recognition process starts from some prior scene knowledge, that is, a generic model of the expected scene and the potential objects. The recognition system constitutes an approach where different low-level vision techniques extract a multitude of image descriptors which are then analyzed using a rule-based reasoning system to interpret the image content. This system has been implemented using a rule-based cooperative expert system

Using petri nets to specify and execute missions for autonomous underwater vehicles

This paper presents the design and implementation of a mission control system (MCS) for an autonomous underwater vehicle (AUV) based on Petri nets. In the proposed approach the Petri nets are used to specify as well as to execute the desired autonomous vehicle mission. The mission is easily described using an imperative programming language called mission control language (MCL) that formally describes the mission execution thread. A mission control language compiler (MCL-C) able to automatically translate the MCL into a Petri net is described and a real-time Petri net player that allows to execute the resulting Petri net onboard an AUV are also presented

Visual SLAM for 3D large-scale seabed acquisition employing underwater vehicles

This paper presents a novel technique to align partial 3D reconstructions of the seabed acquired by a stereo camera mounted on an autonomous underwater vehicle. Vehicle localization and seabed mapping is performed simultaneously by means of an Extended Kalman Filter. Passive landmarks are detected on the images and characterized considering 2D and 3D features. Landmarks are re-observed while the robot is navigating and data association becomes easier but robust. Once the survey is completed, vehicle trajectory is smoothed by a Rauch-Tung-Striebel filter obtaining an even better alignment of the 3D views and yet a large-scale acquisition of the seabed

Visual SLAM for underwater vehicles using video velocity log and natural landmarks

A visual SLAM system has been implemented and optimised for real-time deployment on an AUV equipped with calibrated stereo cameras. The system incorporates a novel approach to landmark description in which landmarks are local sub maps that consist of a cloud of 3D points and their associated SIFT/SURF descriptors. Landmarks are also sparsely distributed which simplifies and accelerates data association and map updates. In addition to landmark-based localisation the system utilises visual odometry to estimate the pose of the vehicle in 6 degrees of freedom by identifying temporal matches between consecutive local sub maps and computing the motion. Both the extended Kalman filter and unscented Kalman filter have been considered for filtering the observations. The output of the filter is also smoothed using the Rauch-Tung-Striebel (RTS) method to obtain a better alignment of the sequence of local sub maps and to deliver a large-scale 3D acquisition of the surveyed area. Synthetic experiments have been performed using a simulation environment in which ray tracing is used to generate synthetic images for the stereo system

Sonic Labyrinths - 3 upon a ground (dance mix)

Electronic music based on an algorithm, but with a good deal of human influence. See other items with keywords 'sonic labyrinths' for details.

Sonic Labyrinths - 3 upon a ground (minimal mix)

Electronic music based on an algorithm, but with a good deal of human influence. See other items with keywords 'sonic labyrinths' for details.

Les Carr explains the moral high ground on open educational resources

In this video, taken in front of the Parthenon at the Acropolis in Athens, Su White interviews Les Carr about why he asserts that there is a moral duty for teachers who create educational content to put that content in the public domain, rather than hoarding it in their institution.