From SIR to SEAIRD: A novel data-driven modeling approach based on the Grey-box System Theory to predict the dynamics of COVID-19

Applied Intelligence - Common compartmental modeling for COVID-19 is based on a priori knowledge and numerous assumptions. Additionally, they do not systematically incorporate asymptomatic cases....     

Toward the heat convection enhancement of nanofluids flowing in a 3D microchannel affected by a nonuniform magnetic field

In the present investigation, the behavior of laminar convective flow and heat transfer in a three-dimensional horizontal square duct using different water-based nanofluids (Fe₃O₄/water, and carbon nanotubes/water) is numerically investigated. The channel is subjected to a periodic partial or full magnetic field. The outer surface is subjected to a constant heat flux density. The problem is numerically solved via the finite volume method with a second-order precision. The numerical simulations covered a range of the Reynolds number 50 ≤ Re ≤ 400, Hartmann number 0 ≤ Ha ≤ 50, and concentration of nanoparticles 0 ≤ ϕ ≤ 0.02 for different modes of the magnetic field application and direction. Examination of the hydrodynamic and thermal behavior shows significant heat transfer performances obtained when applying transversal and partial periodic magnetic fields simultaneously. More precisely, it is found that the favorable protocol improved the heat transfer rate by 85% in the duct flowing by the Ferrofluid at Ha = 50. Furthermore, findings illustrate that the overall heat transfer rate presented in terms of the mean Nusselt number and the highest compromise (heat transfer augmentation-pressure losses diminution) are obtained in the case of Fe₃O₄ nanoparticles for all taken values of Reynolds and Hartmann numbers, whatever the manner and direction of the applied magnetic field.     

Study of C.I. Reactive Yellow 145, C.I. Reactive Red 238 and C.I. Reactive Blue 235 dyestuffs in order to use them in color formulation. Part 2: modeling and optimization of dyeing performances

Abstract

This article models and optimizes the effect of dyeing parameters on obtained color of fabric samples dyed with three cold bifunctional reactive dyes, namely, C.I. Reactive Yellow 145, C.I. Reactive Red 238 and C.I. Reactive Blue 235, in order to use them in color formulation. The studied dyeing parameters are electrolyte concentration, alkali concentration, liquor-to-fiber ratio and temperature of dyeing process. The influence of these parameters was analyzed for four different shades: 0.1%, 1%, 2% and 4%. Two criteria of evaluation are studied and optimized: the exhaustion and the fixation yields. Linear modeling of optimal concentrations of electrolyte and alkali according to the dye concentration was developed, allowing the calculation of optimal quantities which should be added to the dye bath for any dye concentration. Color coordinates and fastness (washing, rubbing and light fastness) of samples dyed with optimal conditions are also evaluated and discussed.     

Towards understanding socio-cognitive behaviors of crowds from visual surveillance data

Multimedia Tools and Applications - The problem of understanding socio-cognitive aspects of crowd behavior is a challenging yet critical task particularly for human-computer interaction...     

Using the expert system to analyze loom performance

In this paper, the development of a warp tension simulation is presented. A system analysis of modern weaving machines led to a suitable simulation model to calculate the warp tension. The validation of the simulation demonstrates that the results correspond well with reality. In a second step, an improved model of this simulation was used in combination with a genetic algorithm and a gradient-based method to calculate optimized setting parameters for the weaving process. In order to do so, a cost function was defined taking into account a desired course of the warp tension. Actually, it is known, that a low and constant warp tension course is suitable for weaving. Using the genetic algorithm or the gradient-based method leads to optimized weaving machine parameters. Both algorithms do get nearly the same results for the optimized weaving machine setting. Applying the optimized setting parameters on a loom did not demonstrate that the productivity of a weaving machine can be raised. Analysis of the produced fabrics did not show an influence of optimization on the fabric quality. The reduction of warp tension was not sufficient in order to have an impact on the mechanical properties of the fabric. Thus, fabric defects could be eliminated using the optimized weaving machine settings.     

Earliness–tardiness minimization on a single machine to schedule preventive maintenance tasks: metaheuristic and exact methods

In this paper, we consider the problem of scheduling a set of M preventive maintenance tasks to be performed on M machines. The machines are assigned to execute production tasks. We aim to minimize the total preventive maintenance cost such that the maintenance tasks have to continuously be run during the schedule horizon. Such a constraint holds when the maintenance resources are not sufficient. We solve the problem by two exact methods and meta-heuristic algorithms. As exact procedures we used linear programming and branch and bound methods. As meta-heuristics, we propose a local search approach as well as a genetic algorithm. Computational experiments are performed on randomly generated instances to show that the proposed methods produce appropriate solutions for the problem. The computational results show that the deviation of the meta-heuristics solutions to the optimal one is very small, which confirms the effectiveness of meta-heuristics as new approaches for solving hard scheduling problems.     

Lithium diffusion profile onto highly resistive p-type silicon

In this work, the effect of temperature and time of diffusion on the lithium (Li) profile into p-type highly resistive silicon have been investigated. The high-purity Li metal (99.995%) was deposited onto p-type (1 1 1) silicon surface and thermally diffused into the bulk at a 2×10⁻⁶ Torr vacuum pressure. The four-probes technique was used to determine the diffusion profile of Li impurities into silicon. Scanning electron microscopy (SEM) was used to measure the diffused junction depth (X_j). The Li diffusion constant D_Li was then extracted using the measured surface concentration N_Li. Thus, the variation of D_Li as a function of diffusion temperature was determined. Simulated profiles was obtained by means PC1D calculate tool. A good agreement was found when the simulated and experimental results were compared with those of the literature values.     

Comments on “A General Model of Multipath Error for Coherently Tracked BOC Modulated Signals”

The mathematical formulation of the discriminator and the multipath error models presented by Harris and Lightsey contains some typing errors. In this comment, we review the formalism of aforementioned models and we fix and correct these typing errors. The simulation results show that the original analytical models, with these corrections, coincide with the numerical models.