Systematic measurements and simulations are reported for the transition from growth by nucleation accretion of two-dimensional islands to step advancement on misoriented GaAs(001) surfaces during epitaxial growth. The conditions have been chosen in order satisfy as much possible underlying assumptions a solid-on-solid model growth, namely, that adatom mobility is isotropic (by using surface toward [010] direction), effect As not rate determining As/Ga ratio 2.5), presence any reconstruction...

We report an analytic derivation of the Langevin equations motion for surface a solid that evolves under typical epitaxial-growth conditions. Our treatment begins with master-equation description microscopic dynamics solid-on-solid model and presumes all processes obey Arrhenius-type rate laws. basic takes account atomic deposition from low-density vapor, thermal desorption, diffusion. Refinements to include effects hot-atom knockout asymmetric energy barriers near step edges. A...

COVID-19 has become a major global issue with large social-economic and health impacts, which led to important changes in people's behavior. One of these affected the way people use public transport. In this work we present data-driven analysis impact on transport demand Community Madrid, Spain, using data from ticket validations between February September 2020. This period time covers all stages pandemic including de-escalation phases. We find that ridership dramatically decreased by 95% at...

Reentrant layer-by-layer growth is studied using a Monte Carlo simulation of solid-on-solid model. A previously proposed explanation the phenomenon based on existence an activation barrier for adatom hops off descending steps has been used to reproduce correctly most available experimental data. However, detailed inspection kinetics, we propose different interpretation origin low-temperature growth, which stresses importance incorporation mechanism atom arriving surface.

The misorientation direction dependence of the transition from growth by formation and coalescence two-dimensional clusters to step advancement has been examined systematically with reflection high-energy electron-diffraction (RHEED) measurements during molecular-beam epitaxy on GaAs(001). Accompanying simulations a solid-on-solid model have reproduced qualitatively all dominant features measured RHEED through comparisons based upon densities simulated surfaces. We reported earlier that Ga...

The development of advanced driver assistance systems (ADASs) will be a crucial element in the construction future intelligent transportation with objective reducing number traffic accidents and their subsequent fatalities. Specifically, driving behaviors could monitored online to determine crash risk provide warning information via ADAS. In this paper, we focus on aggressiveness as one potential causes accidents. We demonstrate that can detected by monitoring external signals such lateral...

Indoor location systems based on IEEE 802.11b (WiFi) mobile devices often rely the received signal strength indicator to estimate user position. Two key characteristics of these have not yet been fully analyzed, namely, temporal and spatial sampling process required adequately describe distribution electromagnetic field in indoor scenarios; device calibration, necessary for supporting different within same system. By using a previously proposed nonparametric methodology system comparison, we...

COVID-19 has dramatically struck each section of our society: health, economy, employment, and mobility. This work presents a data-driven characterization the impact pandemic on public private mobility in mid-size city Spain (Fuenlabrada). Our analysis used real data collected from transport smart card system Bluetooth traffic monitoring network, February to September 2020, thus covering relevant phases pandemic. results show that, at peak pandemic, decreased 95% 86% their pre-COVID-19...

Abstract E-scooter services have multiplied worldwide as a form of urban transport. Their use has grown so quickly that policymakers and researchers still need to understand their interrelation with other transport modes. At present, e-scooter are primarily seen first-and-last-mile solution for public However, we demonstrate $$50\,\%$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>50</mml:mn> <mml:mspace/> <mml:mo>%</mml:mo> </mml:mrow> </mml:math> trips either...

Indoor location (IL) using received signal strength (RSS) is receiving much attention, mainly due to its ease of use in deployed IEEE 802.11b (Wi-Fi) wireless networks. Fingerprinting the most widely used technique. It consists estimating position by comparison a set RSS measurements, made mobile device, with database measurements whose locations are known. However, convenient data structure be and actual performance proposed fingerprinting algorithms still controversial. In addition,...

A Bluetooth traffic monitoring system (BTMS) is capable of identifying vehicles and estimate their travel time (TT) in a route. This information key for intelligent transportation systems. Although BTMSs are currently deployed several cities throughout the world, there no formal methodology TT estimation they generate. In this paper, we first analyze specific features technology that affect estimation. particular, study reliability measurements, representativeness estimates, issues regarding...

Reflection high-energy electron diffraction (RHEED) measurements have been carried out on vicinal GaAs(001) surfaces which are misoriented by 2° and 3° toward the [010] direction. The misorientation-angle dependence Ga-flux of growth-mode transitions for a fixed As/Ga ratio approximately 2.5 reproduced Monte Carlo simulations solid-on-solid model. surface step-density evolutions generated remarkably similar in profile to measured RHEED oscillations, show same relative change amplitude with...

The exponents that characterize the asymptotic scaling behavior of a solid-on-solid model epitaxial growth are obtained from Monte Carlo simulations in several substrate dimensions. This has been used successfully past for quantitative analysis molecular-beam-epitaxy experiments transient regime. d=1, 2, and 3 dimensions agree with those predicted on basis an analytic proposed by Villain Lai Das Sarma. In d=1 we find crossover linear model.

The explosion of the Internet Things has dramatically increased data load on networks that cannot indefinitely increment their capacity to support these new services. Edge computing is a viable approach fuse and process sensor platforms so information can be created locally. However, integration complex heterogeneous sensors producing great amount diverse opens challenges faced. Rather than generating usable straight away, demand prior calculations supply meaningful information. In addition,...

We present computer simulations of growth interruption in Si(001) molecular-beam epitaxy. Inclusion an explicit anisotropy surface nearest-neighbor diffusion barriers enables detailed reproduction observed layer completion dependencies the recovery profile reflection high-energy electron-diffraction (RHEED) specular intensity. The origin this dependency is identified and discussed light sensitivity RHEED intensity to morphology.

We report the observation of a thermally driven monolayer to bilayer transition in period reflection high-energy electron diffraction oscillations during molecular beam epitaxy on Si(001). This behavior is reproduced Monte Carlo growth simulation, from which we infer origin results competition between incorporation and diffusion kinetics.

AbstractAdvanced traffic management systems rely heavily on technology to perform accurate estimations of the current state as well its short-term evolution. The objectives are improving flow and enhancing road safety. Their success is based monitoring two key variables, specifically speed occupancy. latter has, date, received significantly less attention from scientific community. In this work we present a lightweight method “on-line” occupancy estimation. We first propose three...