Search results for "traje"
showing 10 items of 382 documents
Localization of hidden Chua's attractors
2011
Abstract The classical attractors of Lorenz, Rossler, Chua, Chen, and other widely-known attractors are those excited from unstable equilibria. From computational point of view this allows one to use numerical method, in which after transient process a trajectory, started from a point of unstable manifold in the neighborhood of equilibrium, reaches an attractor and identifies it. However there are attractors of another type: hidden attractors, a basin of attraction of which does not contain neighborhoods of equilibria . In the present Letter for localization of hidden attractors of Chuaʼs circuit it is suggested to use a special analytical–numerical algorithm.
Functional Analysis Method for Nonlinear Theory of Gyrotrons
2019
This paper proposes an analyzing method for the nonlinear theory of gyrotrons based on the functional analysis theory. This method is computationally efficient and highly practical, and the results have good accuracy as that of the self-consistent theory. Moreover, the stability of the gyrotron can be easily analyzed by the trajectory of the mapped efficiency space based on the fixed point of the functional analysis theory. The validity and effectiveness of the presented method are verified by the results of self-consistent theory and experiments presented in the references, such as typical examples of gyrotrons working at various frequencies and modes.
Proton Direct Ionization Upsets at Tens of MeV
2023
Experimental monoenergetic proton single-event upset (SEU) cross sections of a 65-nm low core-voltage static random access memory (SRAM) were found to be exceptionally high not only at low energies ($ 3 MeV and extending up to tens of MeV. The SEU cross Section from 20-MeV protons exceeds the 200-MeV proton SEU cross Section by almost a factor of 3. Similarly, monoenergetic neutron cross sections at 14 MeV are about a factor of 3 lower than the 20-MeV proton cross section. Because of Monte Carlo (MC) simulations, it was determined that this strong enhancement is due to the proton direct ionization process as opposed to the elastic and inelastic scattering processes that dominate the SEU res…
State feedback control against sensor faults for Lipschitz nonlinear systems via new sliding mode observer techniques
2011
This paper investigates the problem of simultaneous state and fault estimation and observer-based fault tolerant controller design for Lipschitz nonlinear systems with sensor failure. A new estimation technique is presented in this paper to deal with this design problem. In the proposed approaches, the original system is first augmented by a descriptor model transformation, then a new Proportional and Derivative sliding mode observer technique is developed to obtain accurate estimations of both system states and sensor faults. The designing observer is generalized from the PD observer in [3], but is not a trivial extension. Based on the state estimates, a observer-based control strategy is …
A Planning and Control System for Self-Driving Racing Vehicles
2018
Autonomous robots will soon enter our everyday life as self-driving cars. These vehicles are designed to behave according to certain sets of cooperative rules, such as traffic ones, and to respond to events that might be unpredictable in their occurrence but predictable in their nature, such as a pedestrian suddenly crossing a street, or another car losing control. As civilian autonomous cars will cross the road, racing autonomous cars are under development, which will require superior Artificial Intelligence Drivers to perform in structured but uncertain conditions. We describe some preliminary results obtained during the development of a planning and control system as key elements of an A…
A system-level mathematical model of Basal Ganglia motor-circuit for kinematic planning of arm movements
2017
International audience; In this paper, a novel system-level mathematical model of the Basal Ganglia (BG) for kinematic planning, is proposed. An arm composed of several segments presents a geometric redundancy. Thus, selecting one trajectory among an infinite number of possible ones requires overcoming redundancy, according to some kinds of optimization. Solving this optimization is assumed to be the function of BG in planning. In the proposed model, first, a mathematical solution of kinematic planning is proposed for movements of a redundant arm in a plane, based on minimizing energy consumption. Next, the function of each part in the model is interpreted as a possible role of a nucleus of…
Improved Performance in Quadrotor Trajectory Tracking Using MIMO PIλ-D Control
2022
This paper aims to develop a fractional control approach for quadrotor trajectory tracking. A fractional-order integrator (PIλ) with a feedback derivative scheme is designed to control each state of the MIMO system. The designed feedback controller stabilizes the initially unstable decoupled states and widens the stability, while PIλ provides precise trajectory tracking capabilities. After a successful simulation study, the new PIλ-D controller is implemented in the hardware environment. The various performance and load disturbance analyses reveal the effectiveness of the proposed scheme compared with the classical PD/PID controllers. The real-time study also shows that this scheme is a sim…
The Moderating Role of Work-Related Rumination in Nurses’ Sleep Quality Trajectory During Morning Shift Work
2020
Abstract. This diary study investigated nurses’ recovery after transitioning to morning shift work (i.e., their short-term adaptation to shift work) by examining the change trajectory of sleep quality over the course of five consecutive morning shifts. Results of latent growth analyses ( N = 132) showed that nurses’ sleep quality started at low levels and increased rapidly in the beginning until it stabilized toward the end of the shift work period. Moreover, work-related rumination moderated the sleep quality trajectory. When rumination was low, nurses’ sleep quality showed a quadratic trajectory, whereas when rumination was high, sleep quality showed a flatter and linear trajectory, sugg…
Reliability and validity evidence of the early numeracy test for identifying children at risk for mathematical learning difficulties
2020
Abstract This study investigated reliability and validity evidence regarding the Early Numeracy test (EN-test) in a sample of 1139 Swedish-speaking children (587 girls) in kindergarten (n = 361), first grade (n = 321), and second grade (n = 457). Structural validity evidence was established through confirmatory factor analysis (CFA), which showed that a four-factor model fit the data significantly better than a one-factor or two-factor model. The known-group and cross-cultural validity were established through multigroup CFAs, finding that the four-factor model fit the gender, age and language groups equally well. Internal consistency for the test and sub-skills varied from good to excellen…
Les trajectoires scolaires des élèves issus de l'immigration selon le genre et l'origine : quelles évolutions ?
2016
En ligne sur http://www.cnesco.fr/wp-content/uploads/2016/09/brinbaum1.pdf; L'objectif de ce rapport est d'actualiser les connaissances sur la scolarité des élèves dits de la "seconde génération" -nés en France de parents immigrés - en prenant en compte la diversité des origines. Sont mobilisés quatre indicateurs : les notes en 6e et en 3e, la situation scolaire en 2012-2013 soit six ans après l'entrée en 6e (avec les filières suivies) et les aspirations des familles.