Search results for " Control"
showing 10 items of 7691 documents
Geometric optimal control : homotopic methods and applications
2012
This work is about geometric optimal control applied to celestial and quantum mechanics. We first dealt with the minimum fuel consumption problem of transfering a satellite around the Earth. This brought to the creation of the code HamPath which permits first of all to solve optimal control problem for which the command law is smooth. It is based on the Pontryagin Maximum Principle (PMP) and on the notion of conjugate point. This program combines shooting method, differential homotopic methods and tools to compute second order optimality conditions. Then we are interested in quantum control. We study first a system which consists in two different particles of spin 1/2 having two different r…
Şeffaf cisimlerim 3B taranması
2010
Many practical tasks in industry, such as automatic inspection or robot vision, often require scanning of three-dimensional shapes with non-contact techniques. However, transparent objects, such as those made of glass, still pose difficulties for classical scanning techniques. The reconstruction of surface geometry for transparent objects is complicated by the fact that light is transmitted through, refracted and in some cases reflected by the surface. Current approaches can only deal relatively well with sub-classes of objects. The algorithms are still very specific and not generally applicable. Furthermore, many techniques require considerable acquisition effort and careful calibration. T…
Equivalence of Open-Loop and Closed-Loop Operation of SAW Resonators and Delay Lines
2019
International audience; Surface acoustic wave (SAW) sensors in the form of two-port resonators or delay lines are widely used in various fields of application. The readout of such sensors is achieved by electronic systems operating either in an open-loop or in a closed-loop configuration. The mode of operation of the sensor system is usually chosen based on requirements like, e.g., bandwidth, dynamic range, linearity, costs, and immunity against environmental influences. Because the limit of detection (LOD) at the output of a sensor system is often one of the most important figures of merit, both readout structures, i.e., open-loop and closed-loop systems, are analyzed in terms of the minim…
Temporal-range estimation of multiple objects: evidence for an early bottleneck.
2011
When making parallel time-to-contact (TTC) estimates of two approaching objects, the two respective TTC estimates interfere with one another in an asymmetric fashion. The TTC of the later-arriving object is systematically overestimated, while the estimated TTC for the first-arriving object is as accurate as in a condition presenting only a single object. This asymmetric interference points to a processing bottleneck that could be due to early (e.g., during the estimation of the TTC from the optic flow) or late (e.g., during the timing of the response or the motor execution) constraints in the TTC estimation process. We used a Sperling-like prediction-motion task to differentiate between the…
Frequency Stability Measurement of Cryogenic Sapphire Oscillators with a Multichannel Tracking DDS and the Two-Sample Covariance
2018
This article shows the first measurement of three 100 MHz signals exhibiting fluctuations from 2E-16 to parts in 1E-15 for integration time tau between 1 s and 1 day. Such stable signals are provided by three Cryogenic Sapphire Oscillators (CSOs) operating at about 10 GHz, also delivering the 100 MHz output via a dedicated synthesizer. The measurement is made possible by a 6-channel Tracking DDS (TDDS) and the two-sample covariance tool, used to estimate the Allan variance. The use of two TDDS channels per CSO enables high rejection of the instrument background noise. The covariance outperforms the Three-Cornered Hat (TCH) method in that the background converges to zero "out of the box," wi…
A new loading problem: product size reduction
2017
International audience
Comparación de las lesiones por accidente de trabajo en trabajadores extranjeros y españoles por actividad económica y comunidad autónoma (España, 20…
2008
Fundamento: Aunque el colectivo de personas inmigrantes en nuestro país se ha incrementado notablemente en los últimos años, poco se sabe de sus condiciones de trabajo y de los efectos de éstas en términos de lesiones por accidentes de trabajo. El objetivo de este trabajo fue comparar, para el año 2005, la incidencia de lesiones mortales y no mortales de las personas extranjeras con las de las españolas por actividad económica y comunidad autónoma. Métodos: Los datos de lesiones por accidentes de trabajo (LAT) procedieron del Registro de Accidentes de Trabajo del Ministerio de Trabajo y Asuntos Sociales y los denominadores se obtuvieron de las estadísticas disponibles sobre afiliación a la …
Taking action or thinking about it? : State orientation and rumination are correlated in athletes
2019
Athletic performance in competitive sports relies heavily on the ability to cope effectively with stressful situations. In contrast, some athletes report that their thoughts revolve around the future or past and not around the actual demands during competitions. In those specific stressful situations, the lack of focus like an unintended fixation on repetitive cognitions can have fatal consequences with regard to the performance. Especially when competitors are close in their athletic capabilities, differences in effectively coping with stress and mental stability may decide about winning and losing. One established factor of performing effectively under pressure is the individual tendency …
Associations of adverse childhood experiences and bullying on physical pain in the general population of Germany
2018
Rebecca C Brown,1,* Paul L Plener,1,2,* Elmar Braehler,3,4 Joerg M Fegert,1 Markus Huber-Lang5 1Department of Child and Adolescent Psychiatry/Psychotherapy, University of Ulm, Ulm, Germany; 2Department of Child and Adolescent Psychiatry, Medical University of Vienna, Vienna, Austria; 3Department of Psychosomatic Medicine and Psychotherapy, University Medical Center of The Johannes Gutenberg University of Mainz, Mainz, Germany; 4University of Leipzig, Department of Medical Psychology and Medical Sociology, Leipzig, Germany; 5Institute of Clinical and Experimental Trauma-Immunology, University of Ulm, Ulm, Germany *These authors contributed equally to this work Background: Chronic pain is a f…
Harmonic Balance Method and Stability of Discontinuous Systems
2019
The development of the theory of discontinuous dynamical systems and differential inclusions was not only due to research in the field of abstract mathematics but also a result of studies of particular problems in mechanics. One of first methods, used for the analysis of dynamics in discontinuous mechanical systems, was the harmonic balance method developed in the thirties of the 20th century. In our work the results of analysis obtained by the method of harmonic balance, which is an approximate method, are compared with the results obtained by rigorous mathematical methods and numerical simulation. peerReviewed