Search results for " feedback"
showing 10 items of 291 documents
Q-switching of an erbium-doped fibre laser modulated by a Bragg grating fixed to a piezoelectric
2003
The performance of the Q-switched erbium-doped fibre laser with two fibre Bragg gratings as cavity mirrors was theoretically analysed, employing a set of rate equations for the ion populations and the photon flux inside the cavity. The simulation considers a system where the pulsed laser emission is produced by the temporal modulation of a Bragg grating fixed to a piezoelectric and operating in the 1550 nm spectral region. The temporal evolution of different frequency components of the laser emission produced is governed by the instantaneous overlap between the two gratings. Theoretical results are in agreement with previously reported experimental values.
Tunable Dual-Wavelength Thulium-Doped Fiber Laser Based on FBGs and a Hi-Bi FOLM
2017
A tunable dual-wavelength thulium doped fiber laser is demonstrated experimentally. For the first time for the 2- $\mu \text{m}$ wavelength band we propose the independent tuning of the generated laser lines based on fiber Bragg gratings and the use of a Hi-Bi fiber optic loop mirror for the fine adjustment of the cavity losses to obtain stable dual-wavelength operation. Dual-wavelength laser generation with the laser lines separation in the range from 0.3 to 6.5 nm is obtained. The laser emission exhibits an optical signal-to-noise ratio better than 56 dB. Improved stability with output power fluctuations less than 1 dB is observed in dual-wavelength generation with equal power of lines.
Robust reliable control of uncertain discrete impulsive switched systems with state delays
2013
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2013/197819 Open access This paper is concerned with the problem of robust reliable control for a class of uncertain discrete impulsive switched systems with state delays, where the actuators are subjected to failures. The parameter uncertainties are assumed to be norm-bounded, and the average dwell time approach is utilized for the stability analysis and controller design. Firstly, an exponential stability criterion is established in terms of linear matrix inequalities (LMIs). Then, a state feedback controller is constructed for the underlyin…
Robust control of uncertain multi-inventory systems via linear matrix inequality
2008
We consider a continuous time linear multi inventory system with unknown demands bounded within ellipsoids and controls bounded within ellipsoids or polytopes. We address the problem of "-stabilizing the inventory since this implies some reduction of the inventory costs. The main results are certain conditions under which "-stabilizability is possible through a saturated linear state feedback control. All the results are based on a Linear Matrix Inequalities (LMIs) approach and on some recent techniques for the modeling and analysis of polytopic systems with saturations.
The Peer Observation: “Mentore” Project at University of Palermo
2019
During the last 6 years at the University of Palermo, a group of academics has been involved in a project called “MENTORE” (“Modifying and ENhancing Teaching through peer Observation and Reflections with Experts.”) The objectives of the project are to help teachers improve their teaching, through the help of two mentors; to experiment new approaches in pilot courses to extend, if useful, to other ones; and to change the traditional model of academic teaching based on one single teacher with the class to go toward a model where there is a group of teachers working together in search of improvements. All the participants of the MENTORE project attend to lectures/workshops on teaching and lear…
Feedback-Based Algorithm for Negotiating Human Preferences and Making Risk Assessment Decisions
2023
Work equipment risk assessment is essential for guaranteeing health and safety of workers in industrial contexts.Many and varied hazards are involved in the use of equipment,which have to be periodically subject to thorough controls required by law. This research proposes a novel hybrid decision-making framework aimed at integrating flexible negotiation on human preferences. This goal will be achieved by establishing effective feedback exchanges with expert(s) familiarwith the field of risk and maintenance of work equipment. We extend a previous research that proposed a user-friendly negotiation procedure to increase consistency of judgments provided by experts about relevant risk factors. …
Video feedback in higher education - a contribution to improving the quality of written feedback
2012
Author's version of an article in the journal: Nordic Journal of Digital Literacy. Also available from the publisher at: http://www.idunn.no/ts/dk/2012/02/video_feedback_in_higher_education_-_a_contribution_to_impr The purpose of this article is to promote the significance of feedback regarding students’ working with written texts in higher education and to point out how technology can develop the quality and form of teachers’ feedback. The results of studies and tests completed in eight separate subject areas demonstrate that video feedback simplifies and increases the efficiency of responding to students’ work, as it allows the opportunity to achieve increased levels of precision and qual…
Sources of nitrous oxide and fate of mineral nitrogen in sub-Arctic permafrost peat soils
2021
Nitrous oxide (N2O) emissions from permafrost-affected terrestrial ecosystems have received little attention, largely because they have been thought to be negligible. Recent studies, however, have shown that there are habitats in subarctic tundra emitting N2O at high rates, such as bare peat surfaces on permafrost peatlands. The processes behind N2O production in these high-emitting habitats are, however, poorly understood. In this study, we established an in situ 15N-labelling experiment with the main objectives to partition the microbial sources of N2O emitted from bare peat surfaces (BP) on permafrost peatlands and to study the fate of ammonium and nitrate in these soils and in adjacent …
Coaches’ Corrective Feedback, Psychological Needs, and Subjective Vitality in Mexican Soccer Players
2021
In the sport context, an essential aspect of an athlete’s development and performance happens during the interaction with the coach while receiving information on the aspects of performance that need to be modified (corrective feedback). Grounded in the Self-Determination Theory and particularly on the basic psychological needs theory, a structural equation model (SEM) was tested with the following sequence: perception of the amount of corrective feedback generated by the coach, perceived legitimacy of corrective feedback, satisfaction of basic psychological needs, and vitality in soccer players. Additionally, simple mediation and serial (double) mediation models were also tested. Participa…
Imbalance of Neuronal Excitability as a Cause of Psychic Disorder
1989
Electrical activity of neurons is characterized by an equilibrium between excitation and inhibition, maintained by negative feedback mechanisms at the cellular, synaptic and neurohumoral level. A central mechanism is the interaction between excitatory calcium currents and inhibitory potassium currents, linked by intracellular calcium concentration. These conductances are located in the somato-dendritic part of the neuron and fundamentally influence spontaneous activity and the processing of synaptic input. The electrical equilibrium is altered by different neuromodulators, such as biogenic amines, peptides, and steroids and by several drugs. Neuromodulatory desequilibration towards increase…