Search results for " COMPUTATION"

A low complexity distributed cluster based algorithm for spatial prediction

2017

Los mapas del entorno radioeléctrico (REM) pueden ser una herramienta esencial para numerosas aplicaciones en las futuras redes inalámbricas 5G. En este trabajo, empleamos un popular método geoestadístico llamado kriging ordinario para estimar el REM de un área cubierta por un eNodeB equipado con múltiples antenas. Los sensores inalámbricos se distribuyen por el área de interés y se organizan clústeres adaptativos de sensores para mejorar la calidad de la estimación del canal. En este trabajo, modificamos el algoritmo de clustering distribuido propuesto en un trabajo anterior para reducir la complejidad de la predicción de kriging. Se realizan simulaciones para detallar la técnica de formac…

Avaluació psicomètrica de l'estimació en numeració i càlcul a l'educació primària

2006

L'estimació en numeració i càlcul ha pres rellevància en les dues darreres dècades per la seva importància i necessitat social i, per aquest motiu, ha estat progressivament inclosa en els currículums de matemàtiques de l'educació obligatòria. Tanmateix, el treball de l'estimació a l'aula es veu reduït freqüentment a les tècniques d'arrodoniment i els alumnes no es mostren hàbils a l'hora de desenvolupar estratègies d'estimació o de decidir quan un càlcul estimat és adient per a una situació problemàtica. En aquest article es presenta un test adreçat a estudiar els processos utilitzats en tasques d'estimació en numeració i càlcul per infants que han acabat l'educació primària. S'explica el m…

A computation study to evaluate indoor gamma dose-rate on the basis of outdoor measurements

2006

Genetic structure and differentiation from early bronze age in the mediterranean island of sicily: Insights from ancient mitochondrial genomes

2022

Sicily is one of the main islands of the Mediterranean Sea, and it is characterized by a variety of archaeological records, material culture and traditions, reflecting the history of migrations and populations’ interaction since its first colonization, during the Paleolithic. These deep and complex demographic and cultural dynamics should have affected the genomic landscape of Sicily at different levels; however, the relative impact of these migrations on the genomic structure and differentiation within the island remains largely unknown. The available Sicilian modern genetic data gave a picture of the current genetic structure, but the paucity of ancient data did not allow so far to make p…

Large numbers of cold positronium atoms created in laser-selected Rydberg states using resonant charge exchange

2016

Lasers are used to control the production of highly excited positronium atoms (Ps*). The laser light excites Cs atoms to Rydberg states that have a large cross section for resonant charge-exchange collisions with cold trapped positrons. For each trial with 30 million trapped positrons, more than 700 000 of the created Ps* have trajectories near the axis of the apparatus, and are detected using Stark ionization. This number of Ps* is 500 times higher than realized in an earlier proof-of-principle demonstration (2004 Phys. Lett. B 597 257). A second charge exchange of these near-axis Ps* with trapped antiprotons could be used to produce cold antihydrogen, and this antihydrogen production is e…

Indefinite integrals involving the incomplete elliptic integrals of the first and second kinds

2016

ABSTRACTA substantial number of indefinite integrals are presented for the incomplete elliptic integrals of the first and second kinds. The number of new results presented is about three times the total number to be found in the current literature. These integrals were obtained with a Lagrangian method based on the differential equations which these functions obey. All results have been checked numerically with Mathematica. Similar results for the incomplete elliptic integral of the third kind will be presented separately.

Indefinite integrals involving the incomplete elliptic integral of the third kind

2016

ABSTRACTA substantial number of new indefinite integrals involving the incomplete elliptic integral of the third kind are presented, together with a few integrals for the other two kinds of incomplete elliptic integral. These have been derived using a Lagrangian method which is based on the differential equations which these functions satisfy. Techniques for obtaining new integrals are discussed, together with transformations of the governing differential equations. Integrals involving products combining elliptic integrals of different kinds are also presented.

Factors affecting basket catheter detection of real and phantom rotors in the atria: A computational study

2018

[EN] Anatomically based procedures to ablate atrial fibrillation (AF) are often successful in terminating paroxysmal AF. However, the ability to terminate persistent AF remains disappointing. New mechanistic approaches use multiple-electrode basket catheter mapping to localize and target AF drivers in the form of rotors but significant concerns remain about their accuracy. We aimed to evaluate how electrode-endocardium distance, far-field sources and inter-electrode distance affect the accuracy of localizing rotors. Sustained rotor activation of the atria was simulated numerically and mapped using a virtual basket catheter with varying electrode densities placed at different positions withi…

Electronic signature of the instantaneous asymmetry in the first coordination shell of liquid water

2013

Interpretation of the X-ray spectra of water as evidence for its asymmetric structure has challenged the conventional symmetric nearly-tetrahedral model and initiated an intense debate about the order and symmetry of the hydrogen bond network in water. Here, we present new insights into the nature of local interactions in water obtained using a novel energy decomposition method. Our simulations reveal that while a water molecule forms, on average, two strong donor and two strong acceptor bonds, there is a significant asymmetry in the energy of these contacts. We demonstrate that this asymmetry is a result of small instantaneous distortions of hydrogen bonds, which appear as fluctuations on …

Quantum logic gates by adiabatic passage

2006

International audience; We present adiabatic passage techniques for the realisation of one and two-qubit quantum Gates. These methods use evolution along dark-states of the system, avoiding decoherence effects such as spontaneous emission. The advantage of these methods is their robustness: they are insensitive to the fluctuations of the parameters and to partial knowledge of the system.