2,705 research outputs found
Quantitative Assessment of Stress Through EEG During a Virtual Reality Stress-Relax Session
This work was supported by the project PGC2018-098813-B-C31 (the Spanish Ministry of Science, Innovation and Universities, by European Regional Development Funds).Recent studies have addressed stress level classification via electroencephalography
(EEG) and machine learning. These works typically use EEG-based features, like power
spectral density (PSD), to develop stress classifiers. Nonetheless, these classifiers are
usually limited to the discrimination of two (stress and no stress) or three (low, medium,
and high) stress levels. In this study we propose an alternative for quantitative stress
assessment based on EEG and regression algorithms. To this aim, we conducted a
group of 23 participants (mean age 22.65 5.48) over a stress-relax experience while
monitoring their EEG. First, we stressed the participants via the Montreal imaging stress
task (MIST), and then we led them through a 360-degree virtual reality (VR) relaxation
experience. Throughout the session, the participants reported their self-perceived stress
level (SPSL) via surveys. Subsequently, we extracted spectral features from the EEG of
the participants and we developed individual models based on regression algorithms
to predict their SPSL. We evaluated stress regression performance in terms of the
mean squared percentage error (MSPE) and the correlation coefficient (R2). The results
yielded from this evaluation (MSPE = 10.62 2.12, R2 = 0.92 0.02) suggest that our
approach predicted the stress level of the participants with remarkable performance.
These results may have a positive impact in diverse areas that could benefit from stress
level quantitative prediction. These areas include research fields like neuromarketing,
and training of professionals such as surgeons, industrial workers, or firefighters, that
often face stressful situations.Spanish Ministry of Science, Innovation and Universities, by European Regional Development Funds PGC2018-098813-B-C3
Quantum Flows for Secret Key Distribution
Despite the unconditionally secure theory of quantum key distribution (QKD), several attacks have been successfully implemented against commercial QKD systems. Those systems have exhibited some flaws, as the secret key rate of corresponding protocols remains unaltered, while the eavesdropper obtains the entire secret key. We propose a new theoretical approach called quantum flows to be able to detect the eavesdropping activity in the channel without requiring additional optical components different from the BB84 protocol because the system can be implemented as a high software module. In this approach, the transmitter interleaves pairs of quantum states, referred to here as parallel and orthogonal (non-orthogonal) states, while the receiver uses active basis selection
Exploiting graphic processing units parallelism to improve intelligent data acquisition system performance in JET's correlation reflectometer
The performance of intelligent data acquisition systems relies heavily on their processing capabilities and local bus bandwidth, especially in applications with high sample rates or high number of channels. This is the case of the self adaptive sampling rate data acquisition system installed as a pilot experiment in KG8B correlation reflectometer at JET. The system, which is based on the ITMS platform, continuously adapts the sample rate during the acquisition depending on the signal bandwidth. In order to do so it must transfer acquired data to a memory buffer in the host processor and run heavy computational algorithms for each data block. The processing capabilities of the host CPU and the bandwidth of the PXI bus limit the maximum sample rate that can be achieved, therefore limiting the maximum bandwidth of the phenomena that can be studied. Graphic processing units (GPU) are becoming an alternative for speeding up compute intensive kernels of scientific, imaging and simulation applications. However, integrating this technology into data acquisition systems is not a straight forward step, not to mention exploiting their parallelism efficiently. This paper discusses the use of GPUs with new high speed data bus interfaces to improve the performance of the self adaptive sampling rate data acquisition system installed on JET. Integration issues are discussed and performance evaluations are presente
Water vapor emission from IRC+10216 and other carbon-rich stars: model predictions and prospects for multitransition observations
We have modeled the emission of H2O rotational lines from the extreme C-rich
star IRC+10216. Our treatment of the excitation of H2O emissions takes into
account the excitation of H2O both through collisions, and through the pumping
of the nu2 and nu3 vibrational states by dust emission and subsequent decay to
the ground state. Regardless of the spatial distribution of the water
molecules, the H2O 1_{10}-1_{01} line at 557 GHz observed by the Submillimeter
Wave Astronomy Satellite (SWAS) is found to be pumped primarily through the
absorption of dust-emitted photons at 6 m in the nu2 band. As noted by
previous authors, the inclusion of radiative pumping lowers the ortho-H2O
abundance required to account for the 557 GHz emission, which is found to be
(0.5-1)x10^{-7} if the presence of H2O is a consequence of vaporization of
orbiting comets or Fischer-Tropsch catalysis. Predictions for other
submillimeter H2O lines that can be observed by the Herschel Space Observatory
(HSO) are reported. Multitransition HSO observations promise to reveal the
spatial distribution of the circumstellar water vapor, discriminating among the
several hypotheses that have been proposed for the origin of the H2O vapor in
the envelope of IRC+10216. We also show that, for observations with HSO, the
H2O 1_{10}-1_{01} 557 GHz line affords the greatest sensitivity in searching
for H2O in other C-rich AGB stars.Comment: 35 pages, 12 figures, to be published in The Astrophysical Journa
Universal structure of the edge states of the fractional quantum Hall states
We present an effective theory for the bulk fractional quantum Hall states on
the Jain sequences on closed surfaces and show that it has a universal form
whose structure does not change from fraction to fraction. The structure of
this effective theory follows from the condition of global consistency of the
flux attachment transformation on closed surfaces. We derive the theory of the
edge states on a disk that follows naturally from this globally consistent
theory on a torus. We find that, for a fully polarized two-dimensional electron
gas, the edge states for all the Jain filling fractions have
only one propagating edge field that carries both energy and charge, and two
non-propagating edge fields of topological origin that are responsible for the
statistics of the excitations. Explicit results are derived for the electron
and quasiparticle operators and for their propagators at the edge. We show that
these operators create states with the correct charge and statistics. It is
found that the tunneling density of states for all the Jain states scales with
frequency as .Comment: 10 page
Unusual Tachycardia Association In A patient Without Structural Heart Disease
We report an unusual association of persistent atrial flutter and bundle branch re-entrant ventricular tachycardia in a young patient without structural heart disease. Atrial flutter masked the infra-Hisian conduction disease, was fundamentally dependent on a long PR interval, and could be a possible trigger of ventricular tachycardia
Particle Swarm Optimization Algorithm with a Bio-Inspired Aging Model
A Particle Swarm Optimization with a Bio-inspired Aging Model (BAM-PSO) algorithm is proposed to alleviate the premature convergence problem of other PSO algorithms. Each particle within the swarm is subjected to aging based on the age-related changes observed in immune system cells. The proposed algorithm is tested with several popular and well-established benchmark functions and its performance is compared to other evolutionary algorithms in both low and high dimensional scenarios. Simulation results reveal that at the cost of computational time, the proposed algorithm has the potential to solve the premature convergence problem that affects PSO-based algorithms; showing good results for both low and high dimensional problems. This work suggests that aging mechanisms do have further implications in computational intelligence
Three Presentations of Takayasu’s Arteritis in Hispanic Patients
Takayasu’s arteritis (TA) is a medium and large vessel vasculitis, defined as a nonspecific aortitis that usually involves the aorta and its branches Kobayashi and Numano (2002). Its etiology remains unclear, and its complications are diverse and severe, including stenosis of the thoracic and abdominal aorta, aortic valve damage and regurgitation, and stenosis of the branches of the aorta. Carotid stenosis, coronary artery aneurysms, and renal artery stenosis resulting in renovascular hypertension are also reported sequellae of TA Kobayashi and Numano (2002). The disease was first described in Japan, but has also been diagnosed in India and Mexico Johnston (2002). Its incidence in the United States has been quoted as 2.6 patients per 1,000,000 people/year Johnston (2002). In Japan, its incidence is 3.6 patients per 1,000,000 patients/year and prevalence is 7.85 patients per 100,000 per year Morita et al. (1996). The natural history of this disease, which is commonly present in Asian populations, has only recently been studied in Hispanic patients despite the notable incidence and prevalence of TA in Mexican, South American, and Indian populations (Johnston 2002, Gamarra et al. 2010 ). We present three cases of Hispanic patients who presented with TA at Olive-View-UCLA Medical Center (OVMC). We review their clinical and radiographic presentations. Finally, we review the literature to compare the clinical features of our three patients with data regarding the presentation of TA in more traditional Asian populations
Integrated phased array transducer for on-board structural health monitoring
Permanently bonded onto a structure, an integrated Phased Array (PhA II) transducer that can provide reliable electromechanical connection with corresponding sophisticated miniaturized ?all in one? SHM electronic device installed directly above it, without need for any interface cabling, during all aerospace structure lifecycle phases and for a huge variety of real harsh service environments of structures to be monitored is presented. This integrated PhA II transducer [1], as a key component of the PAMELA SHM? (Phased Array Monitoring for Enhanced Life Assessment) system, has two principal tasks at the same time, reliably transceive elastic waves in real aerospace service environments and serves as a reliable sole carrier or support for associated integrated on-board SHM electronic device attached above. The PhA II transducer successfully accomplished both required task throughout extensive test campaigns which included low to high temperature tests, temperature cycling, mechanical loading, combined thermo- mechanical loading and vibration resistance, etc. both with and without SHM device attached above due to RTCA DO-160F
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