545 research outputs found
Neurophysiological vigilance characterisation and assessment: Laboratory and realistic validations involving professional air traffic controllers
Vigilance degradation usually causes significant performance decrement. It is also considered the major factor causing the out-of-the-loop phenomenon (OOTL) occurrence. OOTL is strongly related to a high level of automation in operative contexts such as the Air Traffic Management (ATM), and it could lead to a negative impact on the Air Traffic Controllers’ (ATCOs) engagement. As a consequence, being able to monitor the ATCOs’ vigilance would be very important to prevent risky situations. In this context, the present study aimed to characterise and assess the vigilance level by using electroencephalographic (EEG) measures. The first study, involving 13 participants in laboratory settings allowed to find out the neurophysiological features mostly related to vigilance decrements. Those results were also confirmed under realistic ATM settings recruiting 10 professional ATCOs. The results demonstrated that (i) there was a significant performance decrement related to vigilance reduction; (ii) there were no substantial differences between the identified neurophysiological features in controlled and ecological settings, and the EEG-channel configuration defined in laboratory was able to discriminate and classify vigilance changes in ATCOs’ vigilance with high accuracy (up to 84%); (iii) the derived two EEG-channel configuration was able to assess vigilance variations reporting only slight accuracy reduction
Cortical Cataract and Refractive Error
Purpose: To evaluate the relationship between the presence
of cortical cataract and accommodation effort, using refractive
error as a proxy. Methods: Patients between 50 and 90
years, scheduled for cataract surgery, were selected with the
help of a photographic database. Nuclear and cortical cataract
were graded and patients grouped having no cataract,
pure cortical, mixed or pure nuclear cataract. Refraction data
at the time of the photograph was converted to estimated
spherical equivalent refractive error each patient would
have had at the age of 45 years. Results: From the initial 239
eyes from 239 patients, cases with myopia below –6.5 dpt
and hyperopia above 6.5 dpt were excluded, resulting in 199
cases for final analysis. Eyes with no cataract showed the
lowest median refractive error (–3.65 dpt), followed by the
pure nuclear group (–2.69 dpt). The median refractive error
for pure cortical (–0.23 dpt) and mixed cataracts (–0.87 dpt)
were close to emmetropia. Cortical cataracts were found in
37% of myopes, 82% of emmetropes, and 85% of hyperopes.
Conclusion: Emmetropes and hyperopes tend to develop
more cortical cataract than myopes. These cortical cataracts
might be caused by shear stress inside the crystalline lens
due to accommodation efforts at the time of onset of presbyopia
Preliminary results using a P300 brain-computer interface speller: a possible interaction effect between presentation paradigm and set of stimuli
Fernández-Rodríguez Á., Medina-Juliá M.T., Velasco-Álvarez F., Ron-Angevin R. (2019) Preliminary Results Using a P300 Brain-Computer Interface Speller: A Possible Interaction Effect Between Presentation Paradigm and Set of Stimuli. In: Rojas I., Joya G., Catala A. (eds) Advances in Computational Intelligence. IWANN 2019. Lecture Notes in Computer Science, vol 11506. Springer, ChamSeveral proposals to improve the performance controlling a P300-based BCI speller have been studied using the standard row-column presentation (RCP) par-adigm. However, this paradigm could not be suitable for those patients with lack of gaze control. To solve that, the rapid serial visual presentation (RSVP) para-digm, which presents the stimuli located in the same position, has been proposed in previous studies. Thus, the aim of the present work is to assess if a stimuli set of pictures that improves the performance in RCP, could also improve the per-formance in a RSVP paradigm. Six participants have controlled four conditions in a calibration task: letters in RCP, pictures in RCP, letters in RSVP and pictures in RSVP. The results showed that pictures in RCP obtained the best accuracy and information transfer rate. The improvement effect given by pictures was greater in the RCP paradigm than in RSVP. Therefore, the improvements reached under RCP may not be directly transferred to the RSVP.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Recognition of Intentional Violations of Active Constraints in Cooperative Manipulation Tasks
Active Constraints (ACs) are high-level control algorithms deployed to assist a human operator in man-machine cooperative tasks [1], and define regions within which it is safe for the robot to move and cut [2]. To enhance the performance in cooperative surgical tasks,
adaptive constraints have been exploited to optimally adjust the provided level of assistance according to some knowledge of the task, hardware or user. In [3] Hidden Markov Models were used for the run-time detection of the user intention to leave a guidance
constraint to circumvent an obstacle. In this work, we present a novel, Neural Network (NN)-based method for the runtime classification of intentional and unintentional violations of ACs, that is trained on either statistical or frequency features from the enforced
constraint forces. We investigate which set of parameters yield faster and more reliable classification results, both for guidance and regional constraints
Multiphase oxidation of alcohols and sulfides with hydrogen peroxide catalyzedby heteropolyacids
This work describes the application of a multiphase system for the oxidation of alcohols to ketones or
aldehydes, and the selective conversion of sulfides to sulfoxides or sulfones using Keggin-type
heteropolyacids and hydrogen peroxide. Benzylic and secondary alcohols were oxidized to ketones or
aldehydes at 70 °C in good yield and selectivity. Similarly, sulfides were converted to sulfoxides or sulfones at
room temperature with high yields and selectivity
The cosmology dependence of the concentration-mass-redshift relation
The concentrations of dark matter haloes provide crucial information about
their internal structure and how it depends on mass and redshift -- the
so-called concentration-mass-redshift relation, denoted . We present
here an extensive study of the cosmology-dependence of that is based
on a suite of 72 gravity-only, full N-body simulations in which the following
cosmological parameters were varied: , ,
, , , , and
. We characterize the impact of these parameters on
concentrations for different halo masses and redshifts. In agreement with
previous works, and for all cosmologies studied, we find that there exists a
tight correlation between the characteristic densities of dark matter haloes
within their scale radii, , and the critical density of the Universe at
a suitably defined formation time. This finding, when combined with excursion
set modelling of halo formation histories, allows us to accurately predict the
concentrations of dark matter haloes as a function of mass, redshift, and
cosmology. We use our simulations to test the reliability of a number of
published models for predicting halo concentration and highlight when they
succeed or fail to reproduce the cosmological relation.Comment: 11 pages, 9 figure
The effect of thermal treatment on structure and surface composition of PtCo electro-catalysts for application in PEMFCs operating under automotive conditions
Reaction of dialkyl carbonates with alcohols:Defining a scale of the best leaving and entering groups
A series of dialkyl and methyl alkyl carbonates has been synthesized and their reactivity investigated. The behavior of preferential leaving and entering groups for the newly synthesized carbonates has been accurately investigated. Both experimental and computational studies agreed that the scale of leaving groups follows the trend: PhCH2O–, MeO– ≥ EtO–, CH3(CH2)2O–, CH3(CH2)7O– > (CH3)2CHO– > (CH3)3CO–. Accordingly, the scale of the entering group has the same trend, with t-butoxide being the worst entering group. A preliminary attempt to rationalize the nucleofugality trends, limited to the (CH3)3CO– and CH3O– groups, has indicated that a likely origin of the observed trends lies in the different entropic contributions and solvation effects
The effect of thermal treatment on structure and surface composition of PtCo electro-catalysts for application in PEMFCs operating under automotive conditions
Ontem, como aqui escrevi, José Eduardo Moniz, Director-Geral da TVI, fez uma conferência intitulada A Televisão num Mundo Audiovisual em Mudança na UCP. No vídeo, Moniz fala de seis assuntos: 1) televisão generalista e novas plataformas, 2) perfil de oferta para o telespectador, 3) surgimento do quinto canal, 4) três canais de notícias, 5) programação de qualidade, e 6) blocos informativos
smt: a Matlab structured matrices toolbox
We introduce the smt toolbox for Matlab. It implements optimized storage and
fast arithmetics for circulant and Toeplitz matrices, and is intended to be
transparent to the user and easily extensible. It also provides a set of test
matrices, computation of circulant preconditioners, and two fast algorithms for
Toeplitz linear systems.Comment: 19 pages, 1 figure, 1 typo corrected in the abstrac
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