Alarm-Based Prescriptive Process Monitoring

Predictive process monitoring is concerned with the analysis of events produced during the execution of a process in order to predict the future state of ongoing cases thereof. Existing techniques in this field are able to predict, at each step of a case, the likelihood that the case will end up in an undesired outcome. These techniques, however, do not take into account what process workers may do with the generated predictions in order to decrease the likelihood of undesired outcomes. This paper proposes a framework for prescriptive process monitoring, which extends predictive process monitoring approaches with the concepts of alarms, interventions, compensations, and mitigation effects. The framework incorporates a parameterized cost model to assess the cost-benefit tradeoffs of applying prescriptive process monitoring in a given setting. The paper also outlines an approach to optimize the generation of alarms given a dataset and a set of cost model parameters. The proposed approach is empirically evaluated using a range of real-life event logs

Advances in ab-initio theory of Multiferroics. Materials and mechanisms: modelling and understanding

Within the broad class of multiferroics (compounds showing a coexistence of magnetism and ferroelectricity), we focus on the subclass of "improper electronic ferroelectrics", i.e. correlated materials where electronic degrees of freedom (such as spin, charge or orbital) drive ferroelectricity. In particular, in spin-induced ferroelectrics, there is not only a {\em coexistence} of the two intriguing magnetic and dipolar orders; rather, there is such an intimate link that one drives the other, suggesting a giant magnetoelectric coupling. Via first-principles approaches based on density functional theory, we review the microscopic mechanisms at the basis of multiferroicity in several compounds, ranging from transition metal oxides to organic multiferroics (MFs) to organic-inorganic hybrids (i.e. metal-organic frameworks, MOFs)Comment: 22 pages, 9 figure

Annealing study and thermal investigation on bismuth sulfide thin films prepared by chemical bath deposition in basic medium

This is a post-peer-review, pre-copyedit version of an article published in Applied Physics A 124.2 (2018): 166. The final authenticated version is available online at: http://doi.org/10.1007/s00339-018-1584-7Bismuth sulfide thin films were prepared by chemical bath deposition using thiourea as sulfide ion source in basic medium. First, the effects of both the deposition parameters on films growth as well as the annealing effect under argon and sulfur atmosphere on as-deposited thin films were studied. The parameters were found to be influential using the Doehlert matrix experimental design methodology. Ranges for a maximum surface mass of films (3 mg cm-2) were determined. A well crystallized major phase of bismuth sulfide with stoichiometric composition was achieved at 190°C for 3 hours. The prepared thin films were characterized using Grazing Incidence X-ray diffraction (GIXRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDX). Second, the band gap energy value was found to be 1.5 eV. Finally, the thermal properties have been studied for the first time by means of the electropyroelectric (EPE) technique. Indeed, the thermal conductivity varied in the range of 1.20 - 0.60 W m-1 K-1 while the thermal diffusivity values increased in terms of the annealing effect ranging from 1.8 to 3.5 10-7 m2s-1This work was financially supported by the Tunisian Ministry of Higher Education and Scientific Research and by the WINCOST (ENE2016-80788-C5-2-R) project funded by the Spanish Ministry of Economy and Competitivenes

Cold ablation driven by localized forces in alkali halides

Laser ablation has been widely used for a variety of applications. Since the mechanisms for ablation are strongly dependent on the photoexcitation level, so called cold material processing has relied on the use of high-peak-power laser fluences for which nonthermal processes become dominant; often reaching the universal threshold for plasma formation of ∼1 J cm-2 in most solids. Here we show single-shot time-resolved femtosecond electron diffraction, femtosecond optical reflectivity and ion detection experiments to study the evolution of the ablation process that follows femtosecond 400 nm laser excitation in crystalline sodium chloride, caesium iodide and potassium iodide. The phenomenon in this class of materials occurs well below the threshold for plasma formation and even below the melting point. The results reveal fast electronic and localized structural changes that lead to the ejection of particulates and the formation of micron-deep craters, reflecting the very nature of the strong repulsive forces at play

Cellules solaires CdS/CuInS2, préparées par pulvérisation chimique sans air

Nous avons étudié les propriétés structurales et optiques des couches minces de CuInS2 préparées par pulvérisation chimique réactive sans air. L'analyse par diffraction aux rayons X a montré que ces couches sont bien cristallisées et leur orientation principale (112) est nettement privilégiée pour un rapport de concentrations (Cu(I))/(In(III)) = 1 dans la solution à pulvériser. La valeur de la largeur de bande interdite, de l'ordre de 1,45 eV, a été obtenue à partir des mesures de transmission et de réflexion optiques. Les valeurs de la tension de circuit ouvert et de courant de court-circuit, de la photopile CdS/CuInS2 réalisée, sont respectivement de l'ordre de 0,3 V et 2,7 mA. cm-2

Cellules solaires CdS/CuInS2, préparées par pulvérisation chimique sans air

We have studied the structural and optical properties of CuInS2 thin layers prepared by airless spray. The X-ray diffraction analysis showed that these layers are well crystallized with (112) principal orientation which is clearly privileged for a concentration ratio (Cu(I))/(In(III)) = 1 in the pulverization solution. The value of the gap, of the order of 1.45 eV, was obtained from transmission and reflection optical measurements. The values of open circuit voltage and short circuit current of CdS/CuInS 2 cell are respectively of the order of 0.3 V and 2,7 mA. cm-2 .Nous avons étudié les propriétés structurales et optiques des couches minces de CuInS2 préparées par pulvérisation chimique réactive sans air. L'analyse par diffraction aux rayons X a montré que ces couches sont bien cristallisées et leur orientation principale (112) est nettement privilégiée pour un rapport de concentrations (Cu(I))/(In(III)) = 1 dans la solution à pulvériser. La valeur de la largeur de bande interdite, de l'ordre de 1,45 eV, a été obtenue à partir des mesures de transmission et de réflexion optiques. Les valeurs de la tension de circuit ouvert et de courant de court-circuit, de la photopile CdS/CuInS2 réalisée, sont respectivement de l'ordre de 0,3 V et 2,7 mA. cm-2