End-to-end neural network architecture for fraud scoring in card payments

[EN] Millions of euros are lost every year due to fraudulent card transactions. The design and implementation of efficient fraud detection methods is mandatory to minimize such losses. In this paper, we present a neural network based system for fraud detection in banking systems. We use a real world dataset, and describe an end-to-end solution from the practitioner's perspective, by focusing on the following crucial aspects: unbalancedness, data processing and cost metric evaluation. Our analysis shows that the proposed solution achieves comparable performance values with state-of-the-art proprietary and costly solutions. (c) 2017 Elsevier B.V. All rights reserved.Gomez, J.; Arévalo, J.; Paredes Palacios, R.; Nin, J. (2018). End-to-end neural network architecture for fraud scoring in card payments. Pattern Recognition Letters. 105:175-181. https://doi.org/10.1016/j.patrec.2017.08.024S17518110

Type Tests of JT-60SA Central Solenoid / Equilibrium Field (CS/EF) Super-Conducting Magnet Power Supplies

JT-60SA is a Superconducting Tokamak in the framework of the Broader Approach Agreement between Europe and Japan. For this International Project among its various procurements, the Italian National Agency for New Technology Energy and Sustainable Economic Development (ENEA) is providing: four AC/DC converters for the central solenoid superconducting magnets (CS1, CS2, CS3 and CS4 PSs rated ±20 kA and ±1 kV); two AC/DC converters for the Equilibrium Field superconducting magnets (EF1 and EF6 PSs rated in the range +10 kA -20 kA and ±1 kV); and two AC/DC converters Fast Plasma Position Control Coils (rated ±5 kA and ±1 kV). Furthermore, ENEA is also providing six converter transformers of which: four dry type for FPPCC PSs and two oil type for CS PSs. These systems, being procured by ENEA through a contract signed in August 2013 with Industrial Suppliers (Poseico and Jema in Join-Venture), have been already constructed and they are in advanced testing phase. The basic devices of a CS/EF PS consist in: a thyristors rectifier or base PS, a converter transformer, a crowbar (to protect by over-voltages and/or over-currents); whereas the load of the CS/EF PS is a Super-Conducting Magnet, whose purpose is the generation of strong magnetic fields able to induce and confine the plasma current in a prefixed geometrical configuration. This requires that the control system of CS/EF PSs is able to comply with a reference current profile, known as “scenario”. The scenarios are particularly critical in these systems for the high currents required and hence for the high magnetic energy stored. The installed total electric power in JT-60SA is about 400 MVA, with a peak of reactive power equal to 330 MVAR and an energy consumption up to 1.5 GJ. The main characteristics of CS/EF base thyristor rectifier are: 4-quadrant AC/DC converter 12-pulses with circulating current in back-to-back configuration, with a DC current of ±20 kA, a DC voltage of 1 kV and an accuracy of ±1%. The design phase was completed in 2015, the construction of all EF/CS PSs was completed in 2016 whereas all PSs were tested in 2016 except EF PSs that are currently ongoing. All performed type tests were carried out both in closed loop feedback current control and in open loop feed forward voltage control and in accordance to the IEC60146 Standards. The electric load used for these tests the consists of three inductances connected in series, whole resulting values of 3.3mH and 3mΩ. The measure electric scheme is fed by the 30kV electric power grid and by an autotransformer, that offers the possibility to increase or decrease the voltage that is going to the converter transformers, that power the EF/CS PS. These tests, made at full current, pointed out a good dynamic behaviour of the control system both for forward and for reverse rectifier bridges, assuring the smooth transitions between different operating modes: single mode, circulating current mode and dual mode. This is the focus of the paper. The complete systems will be delivered to Japan by 2017.27th IEEE Symposium on Fusion Engineering (SOFE-2017

Type Tests of JT-60SA Central Solenoid / Equilibrium Field (CS/EF) Super-Conducting Magnet Power Supplies

JT-60SA is a superconducting tokamak in theframework of the broader approach agreement between Europeand Japan. For this international project among its various procurements,the Italian National Agency for new technology energyand sustainable economic development (ENEA) is providing fourac/dc converters for the central solenoid (CS) superconductingmagnets, two ac/dc converters for the equilibrium field (EF)superconducting magnets, and two ac/dc converters for the fastplasma position control coils (FPPCC). Furthermore, ENEA isalso providing six converter transformers of which four areof the dry type for FPPCC power supplies (PSs) and two ofoil type for CS PSs. CS/EF PSs feed poloidal superconductingmagnets of JT-60SA, whose purpose is the generation of strongmagnetic fields able to induce and confine the plasma currentin a prefixed geometrical configuration. The control systemof CS/EF PSs has to be able to reproduce in real-time areference current or voltage profile, known as “scenario” andthese are particularly critical in these systems for the highcurrents required and for the high magnetic energy stored in thesuperconducting magnets. All performed type tests, carried outin accordance to the IEC60146 Standards, pointed toward a gooddynamic behavior of the control system both for forward and forreverse rectifier bridges, assuring the smooth transitions betweendifferent operating modes: single mode, circulating current modeand dual mode. This is the focus of this paper