Search results for " Trajectory"
showing 10 items of 36 documents
Maternal body mass index, change in weight status from childhood to late adulthood and physical activity in older age
2021
This study aimed to examine the longitudinal associations of maternal body mass index (BMI), weight status in childhood and late adulthood and device-measured total physical activity (TPA) in older age. The study involves 552 participants from Helsinki Birth Cohort Study who were born in Helsinki, Finland, in 1934-1944. TPA was measured with a multisensory body monitor at a mean age of 70 years and expressed in metabolic equivalent of task hours/day (METh/d). Childhood overweight (BMI > 85th percentile) was based on school health records at 6-7 years of age, and late adulthood overweight (BMI >= 25 kg/m(2)) was based on clinical measurements at the mean age of 61 years. Childhood overweight…
Studies on the response of a water-Cherenkov detector of the Pierre Auger Observatory to atmospheric muons using an RPC hodoscope
2020
Extensive air showers, originating from ultra-high energy cosmic rays, have been successfully measured through the use of arrays of water-Cherenkov detectors (WCDs). Sophisticated analyses exploiting WCD data have made it possible to demonstrate that shower simulations, based on different hadronic-interaction models, cannot reproduce the observed number of muons at the ground. The accurate knowledge of the WCD response to muons is paramount in establishing the exact level of this discrepancy. In this work, we report on a study of the response of a WCD of the Pierre Auger Observatory to atmospheric muons performed with a hodoscope made of resistive plate chambers (RPCs), enabling us to selec…
Operation of the MAMI accelerator with a Wien filter based spin rotation system
2006
A compact spin rotation system based on a Wien filter has been installed at the Mainz microtron accelerator (MAMI). Under operation with varying spin rotation angles a significant change of focal length together with a shift of the central beam trajectory is expected. We demonstrate that these effects can be kept under control. As a consequence operation with spin rotation angles between 0° and ±90° has been achieved without compromising the beam quality and operational stability of MAMI.
Time-optimal control of SU(2) quantum operations
2013
We propose an analysis of the time-optimal control of SU(2) quantum operations. By using the Pontryagin Maximum Principle, we show how to determine the optimal trajectory reaching a given target state. Explicit analytical solutions are given for two specific examples. We discuss the role of the detuning in the construction of the optimal synthesis.
Classical-to-quantum crossover in electron on-demand emission
2017
Emergence of a classical particle trajectory concept from the full quantum description is a key feature of quantum mechanics. Recent progress of solid state on-demand sources has brought single-electron manipulation into the quantum regime, however, the quantum-to-classical crossover remains unprobed. Here we describe theoretically a mechanism for generating single-electron wave packets by tunneling from a driven localized state, and show how to tune the degree of quantumness. Applying our theory to existing on-demand sources, we demonstrate the feasibility of an experimental investigation of quantum-to-classical crossover for single electrons, and open up yet unexplored potential for few-e…
Vinculación entre la vulnerabilidad y la exclusión social y las trayectorias delictivas. Un estudio de asociación
2017
RESUMEN Este estudio tiene por objeto identificar la relación existente entre las trayectorias delictivas y los factores de vulnerabilidad y exclusión social en adolescentes en conflicto con la ley. Para ello se analizan 281 expedientes de adolescentes en conflicto con la ley de la ciudad de València y se generan 3 trayectorias delictivas: inicial, moderada y consolidada, que se asocian a indicadores de vulnerabilidad y exclusión social. Se muestran evidencias empíricas de su relación. Las trayectorias delictivas y los factores de vulnerabilidad y exclusión social se hallan plenamente conectados, entrelazados y superpuestos. La acumulación de factores de vulnerabilidad y exclusión social en…
Robust Discrete-Time Lateral Control of Racecars by Unknown Input Observers
2023
This brief addresses the robust lateral control problem for self-driving racecars. It proposes a discrete-time estimation and control solution consisting of a delayed unknown input-state observer (UIO) and a robust tracking controller. Based on a nominal vehicle model, describing its motion with respect to a generic desired trajectory and requiring no information about the surrounding environment, the observer reconstructs the total force disturbance signal, resulting from imperfect knowledge of the time-varying tire-road interface characteristics, presence of other vehicles nearby, wind gusts, and other model uncertainty. Then, the controller actively compensates the estimated force and as…
Piecewise planar underwater mosaicing
2015
A commonly ignored problem in planar mosaics, yet often present in practice, is the selection of a reference homography reprojection frame where to attach the successive image frames of the mosaic. A bad choice for the reference frame can lead to severe distortions in the mosaic and can degenerate in incorrect configurations after some sequential frame concatenations. This problem is accentuated in uncontrolled underwater acquisition setups as those provided by AUVs or ROVs due to both the noisy trajectory of the acquisition vehicle — with roll and pitch shakes — and to the non-flat nature of the seabed which tends to break the planarity assumption implicit in the mosaic construction. These…
De l'égalité formelle aux usages réels : déterminants et effets du suivi des MOOC dans les trajectoires socio-professionnelles
2018
Education and vocational training are central institutions in today’s society. They play an important role in guaranteeing people’s social and professional integration. They are also considered strategic pillars of economic growth in “the knowledge society” (CE, 2000). However, despite their basis in democratic values and principles, there are still many inequalities in access and outcomes in both compulsory academic and vocational education. Moreover, because of the increasing flexibility and insecurity of work in the current labor market, a diploma is a necessary, but not sufficient, condition for stable employment. In this context, the rise of Massive Open Online Courses (MOOC) raises qu…
Symbolic Reductionist Model for Program Comprehension
2007
This article presents the main features of a novel construction, symbolic analysis, for automatic source code processing. The method is superior to the known methods, because it uses a semiotic, interpretative approach. Its most important processes and characteristics are considered here. We describe symbolic information retrieval and the process of analysis in which it can be used in order to obtain pragmatic information. This, in turn, is useful in understanding a current Java program version when developing a new version.