325 research outputs found

    A recommender system for process discovery

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    Over the last decade, several algorithms for process discovery and process conformance have been proposed. Still, it is well-accepted that there is no dominant algorithm in any of these two disciplines, and then it is often difficult to apply them successfully. Most of these algorithms need a close-to expert knowledge in order to be applied satisfactorily. In this paper, we present a recommender system that uses portfolio-based algorithm selection strategies to face the following problems: to find the best discovery algorithm for the data at hand, and to allow bridging the gap between general users and process mining algorithms. Experiments performed with the developed tool witness the usefulness of the approach for a variety of instances.Peer ReviewedPostprint (author’s final draft

    Low temperature CO oxidation

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    Catalytic low-temperature abatement of carbon monoxide becomes essential in environmental pollution control. CO Oxidation, CO Preferential Oxidation (PROX) and Water Gas Shift (WGS) reaction are the conventional technologies used to remove carbon monoxide at low temperature. Perovskite-type oxides have been extensively studied in the last years as catalysts for these reactions due to their high activity and catalytic stability. This chapter describes the state-of-the-art of using perovskite-based catalysts of general formula ABO3 in these reactions. Key factors such as the type and nature of A and B ions or the formation of oxygen vacancies or interstitials by doping are discussed in the light of the reaction mechanism in each casePeer reviewe

    Gold Functionalized Supported Ionic Liquids Catalyst for CO Oxidation.

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    The present study tries to give an insight to the combination of the homogeneous and heterogeneous catalytic properties in a new class of materials. Well dispersed gold nanoparticles on an ionic liquid layer supported on a mineral carrier have been prepared. This work is concentrated on the characterizations and understanding of the interactions between all the components of the catalytic system. The application of the materials in the reaction of oxidation of carbon monoxide shows rather unexpected results¿a good catalytic activity completely independent of the temperature.L. Bobadilla acknowledges Junta de Andalucía (Project PDG-TEP01965). S. Ivanova and A. Penkova acknowledge MEC for their contracts Ramon y Cajal and Juan de la Cierva.Peer Reviewe

    To dd, or not to dd: Recent developments and comparisons of regularization schemes

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    We give an introduction to several regularization schemes that deal with ultraviolet and infrared singularities appearing in higher-order computations in quantum field theories. Comparing the computation of simple quantities in the various schemes, we point out similarities and differences between them.Comment: 61 pages, 12 figures; version sent to EPJC, references update

    OPTIMIZATION OF COAGULATION PARAMETERS IN THE REMOVAL OF TURBIDITY AND SUSPENDED SOLIDS FROM TANNERY EFFLUENTS USING THE BOX - BEHNKEN DESIGN

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    The present study evaluated the performance of tannery effluent treatments by coagulation processes. This was done by combining each of the organic coagulants L-1544, L-1541, and L-1700 with aluminium sulphate, respectively, as an inorganic coagulant in different mixing ratios. Subsequently, the response surface method optimized the coagulation conditions: agitation speed, time, and total coagulant concentration. The best results were obtained with the cationic coagulant based on L-1544; likewise, by superposition of contours plots, the conditions that maximize the percentages of simultaneous removal of turbidity and suspended solids were determined, the optimum coagulation values being time 4 minutes, agitation speed 169.7 rpm and total coagulant concentration 1354 ppm, obtaining 100 and 61.9 % removal of turbidity and suspended solids respectively. The R-Squared statistics show that the models explain 92.99 % and 93.94 % of the variabilities in turbidity and Suspended Solids Removal, respectively

    Two-Loop Four-Fermion Scattering Amplitude in QED

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    We present the first fully analytic evaluation of the transition amplitude for the scattering of a massless into a massive pair of fermions at the two-loop level in quantum electrodynamics. Our result is an essential ingredient for the determination of the electromagnetic coupling within scattering reactions, beyond the currently known accuracy, which has a crucial impact on the evaluation of the anomalous magnetic moment of the muon. It will allow, in particular, for a precise determination of the leading hadronic contribution to the (g−2)μ in the MUonE experiment at CERN, and therefore can be used to shed light on the current discrepancy between the standard model prediction and the experimental measurement for this important physical observable

    The two-loop four-fermion scattering amplitude in QED

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    We present the analytic evaluation of the two-loop corrections to the amplitude for the scattering of four fermions in Quantum Electrodynamics, f+f++F+F+0f^- + f^+ + F^- + F^+ \to 0, with ff and FF representing a massless and a massive lepton, respectively. Dimensional regularization is employed to evaluate the loop integrals. Ultraviolet divergences are removed by renormalizing the coupling constant in the MS{\overline{\text{MS}}}-scheme, and the lepton mass as well as the external fields in the on-shell scheme. The analytic result for the renormalized amplitude is expressed as Laurent series around d=4d=4 space-time dimensions, and contains Generalized Polylogarithms with up to weight four. The structure of the residual infrared divergences of the virtual amplitude is in agreement with the prediction of the Soft Collinear Effective Theory. Our analytic results are an essential ingredient for the computation of the scattering cross section for massive fermion-pair production in massless fermion-pair annihilation, i.e. ff+FF+f^- f^+ \to F^- F^+, and crossing related processes such as the elastic scattering fFfFf F \to f F, with up to Next-to-Next to Leading Order accuracy.Comment: 5 pages, 2 figures, 1 table + supplemental materia

    May the four be with you: novel IR-subtraction methods to tackle NNLO calculations

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    In this manuscript, we summarise all discussions originated as a result of the WorkStop/ThinkStart 3.0: paving the way to alternative NNLO strategies that took place on 4.-6. November 2019 at the Galileo Galilei Institute for Theoretical Physics (GGI). We gratefully acknowledge the support of GGI and the COST Action CA16201 PARTICLEFACE. We wish to thank toW.M. Marroquin and M. Morandini for their help in organising the workshop. P. Banerjee acknowledges support by the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 701647. A.L. Cherchiglia, B. Hiller and M.Sampaio acknowledge support from Fundacao para a Ciencia e Tecnologia (FCT) through the projects UID/FIS/04564/2020 and CERN/FIS-COM/0035/2019. The work of L. Cieri has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 754496. The work of F. Driencourt-Mangin, G. Rodrigo, G. Sborlini and W.J. Torres Bobadilla is supported by the Spanish Government (Agencia Estatal de Investigacion), ERDF funds from European Commission (Grant No. FPA2017-84445-P), Generalitat Valenciana (Grant No. PROMETEO/2017/053) and from the SpanishGovernment (FJCI-2017-32128). T. Engel acknowledges support by the Swiss National Science Foundation (SNF) under contract 200021_178967. C. Gnendiger, R. Pittau, A. Signer and D. Stockinger wish to thank B. Page for his help in establishing (2.60). The work of R. J. Hernandez-Pinto is supported by CONACyT through the Project No. A1-S-33202 (Ciencia Basica) and Sistema Nacional de Investigadores. G. Pelliccioli was supported by the Bundesministerium fur Bildung und Forschung (BMBF, German Federal Ministry for Education and Research) under contract no. 05H18WWCA1. J. Pires was supported by Fundacao para a Ciencia e Tecnologia (FCT, Portugal) through the contract UIDP/50007/2020 and project CERN/FIS-PAR/0024/2019. The work of R. Pittau has been supported by the SpanishGovernment grant PID2019-106087GB-C21 and by the Junta de Andalucia project P18-FR-4314 (fondos FEDER). M. Sampaio acknowledges a research grant from CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico 303482/2017-6). C. Signorile-Signorile was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Grant no. 396021762 - TRR 257.In this manuscript, we report the outcome of the topical workshop: paving the way to alternative NNLO strategies (https://indico.ific.uv.es/e/WorkStop-ThinkStart_3.0), by presenting a discussion about different frameworks to perform precise higher-order computations for high-energy physics. These approaches implement novel strategies to deal with infrared and ultraviolet singularities in quantum field theories. A special emphasis is devoted to the local cancellation of these singularities, which can enhance the efficiency of computations and lead to discover novel mathematical properties in quantum field theories.European Commission 701647Portuguese Foundation for Science and Technology European Commission UID/FIS/04564/2020 CERN/FIS-COM/0035/2019European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant 754496Spanish Government (Agencia Estatal de Investigacion)ERDF funds from European Commission FPA2017-84445-PGeneralitat Valenciana European Commission PROMETEO/2017/053Spanish Government European Commission FJCI-2017-32128 PID2019-106087GB-C21Swiss National Science Foundation (SNSF) 200021_178967Consejo Nacional de Ciencia y Tecnologia (CONACyT) A1-S-33202Sistema Nacional de InvestigadoresFederal Ministry of Education & Research (BMBF) 05H18WWCA1Portuguese Foundation for Science and Technology UIDP/50007/2020 CERN/FIS-PAR/0024/2019Junta de Andalucia P18-FR-4314Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ) 303482/2017-6German Research Foundation (DFG) 396021762 - TRR 257GGIEuropean Cooperation in Science and Technology (COST) CA16201 PARTICLEFAC

    To d , or not to d : recent developments and comparisons of regularization schemes

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    We give an introduction to several regularization schemes that deal with ultraviolet and infrared singularities appearing in higher-order computations in quantum field theories. Comparing the computation of simple quantities in the various schemes, we point out similarities and differences between them
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