Multi-Objective Recommendations and Promotions at TOTAL

International audienceIn this paper, we revisit the semantics of recommendations and promotional offers using multi-objective optimization principles. We investigate two formulations of product recommendation that go beyond traditional settings by optimizing simultaneously two conflicting objectives: Budget-Reco optimizes two customer-centric goals, namely utility and budget, and Business-Reco optimizes utility, a customer-centric goal, and profit margin, a business-oriented goal. To capture those objectives, we formulate knapsack problems and propose adaptations of exact and approximate algorithms. We also propose Group-Promo, the problem of generating product promotions that we model as a group discovery problem with multiple objectives and develop a Pareto-based solution. Our experiments on our TOTAL datasets demonstrate the importance of multi-objective optimization in the retail context, as well as the usefulness of our solutions when compared to their exact baselines. The results are valuable to TOTAL's marketing department that has been improving hand-crafted strategies by launching several promotional campaigns using our algorithms

Circulating current reduction-based hybrid controller of an electrical drive system fed by two parallel inverters

International audienceThis paper presents a control technique of an electrical drivesystem fed by two parallel-connected voltage source inverters(VSIs). Two types of controllers are used to ensure a correctcontrol of the system under different situations, especially, incase of structural or control imbalances between the two VSIs,which leads to parasitic zero-sequence circulating currents (ZSCC)appearance. So, a linear PI controller and a nonlinear sliding modecontroller are combined together to act simultaneously based on thefrequency separation principle and form hybrid controller.Therefore, the designed controller allows reduced ZSCC and offersstability and robustness against external disturbances. Simulationand experimental investigations shown that the proposed hybridcontroller ensures the control of the drive system with ZSCCsuppression even in the presence of imbalances

Circulating current reduction-based hybrid controller of an electrical drive system fed by two parallel inverters

International audienceThis paper presents a control technique of an electrical drivesystem fed by two parallel-connected voltage source inverters(VSIs). Two types of controllers are used to ensure a correctcontrol of the system under different situations, especially, incase of structural or control imbalances between the two VSIs,which leads to parasitic zero-sequence circulating currents (ZSCC)appearance. So, a linear PI controller and a nonlinear sliding modecontroller are combined together to act simultaneously based on thefrequency separation principle and form hybrid controller.Therefore, the designed controller allows reduced ZSCC and offersstability and robustness against external disturbances. Simulationand experimental investigations shown that the proposed hybridcontroller ensures the control of the drive system with ZSCCsuppression even in the presence of imbalances

Spray Pyrolysis Synthesis of Pure and Mg-Doped Manganese Oxide Thin Films

International audiencePure and Mg-doped manganese oxide thin films were synthesized on heated glass substrates using the spray pyrolysis technique. The surface chemical composition was investigated by the use of X-ray photoelectron spectroscopy (XPS). Structural and morphological properties were studied by using X-ray diffraction (XRD), scanning electron microscope (SEM) and atomic force microscopy (AFM). Optical properties were characterized by UV-visible spectroscopy. XPS spectra showed typical Mn (2p3/2), (2p1/2) and O (1s) peaks of Mn3O4 with a slight shift attributed to the formation of different chemical states of manganese. XRD analysis revealed the tetragonal phase of Mn3O4 with a preferred (211) growth orientation that improved with Mg-doping; likewise, grain size is observed to increase with the Mg doping. SEM images of Mn3O4 films showed rough surfaces composed of uniformly distributed nanograins whose size decreases with the Mg-doping. The manganese oxide films surface observed in AFM show a textured, rough and porous surface. The combination of transmittance and absorption data in the UV-visible range allowed determining the energy values of the Eg band gap (1.5–2.5 eV). The decrease of the band gap with the Mg-doping increase is attributed to the influence of the greater size of the Mg2+ ion in the manganese oxide lattice

A new numerical approach for efficient modeling of positive corona discharge and its associated electric wind

Research on corona wind generation has been increasing in recent years because of its potential technological applications, particularly those related to improving heat transfer in small-scale devices. Since numerical simulations play a key role in the design of these applications, computationally efficient modeling of corona discharge is imperative. This work presents a new approach that allows rapid computation of the electrohydrodynamic (EHD) force density responsible for the generation of electric wind. Arbitrary electrode configurations can easily be dealt with in the model, since only the Laplacian electric field lines have to be determined numerically. Then, using approximated analytical approximations of the electric field intensity along the field lines, the spatial distribution of the current density and the space charge density can be easily determined. The model has been satisfactorily tested against experimental measurements of the current–voltage characteristic and the current density distribution on the cathode. Furthermore, the electric wind computed from the EHD force agrees quite satisfactorily with measurements carried out in different electrode configurations. Finally, the model has been applied to a new electrode configuration that has greater potential for heat transfer applications

An ML-Powered Human Behavior Management System

International audienceOur work aims to develop novel technologies for building an efficient data infrastructure as a backbone for a human behavior management system. Our infrastructure aims at facilitating behavior modeling, discovery, and exploitation, leading to two major outcomes: a behavior data management back-end and a high-level behavior specification API that supports mining, indexing and search, and AI-powered algorithms that provide the ability to extract insights on human behavior and to leverage data to advance human capital. We discuss the role of ML in populating and maintaining the back-end, and in exploiting it for human interest