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1. How does Internationalisation affect the productivity of R&D activities in large innovative firms? A conditional nonparametric investigation

Author

Laurens, P., Toma, P., Schoen, A., Daraio, C., Laredo, P., Laboratoire Interdisciplinaire Sciences, Innovations, Sociétés (LISIS), Institut National de la Recherche Agronomique (INRA)-Université Paris-Est Marne-la-Vallée (UPEM)-ESIEE Paris-Centre National de la Recherche Scientifique (CNRS), Laurens, Patricia, Toma, Pierluigi, Schoen, Antoine, Daraio, Cinzia, Larédo, Philippe, Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Gustave Eiffel, University of Salento [Lecce], Department of Informatics and System Sciences (Sapienza University of Rome), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), University of Manchester [Manchester], The research has received funding from RISIS projects funded by the European Union's Seventh Framework Programme FP7/RISIS project, 313082) and the European Union's H2020/RISIS2 project, 821491)., European Project: 313082,EC:FP7:INFRA,FP7-INFRASTRUCTURES-2012-1,RISIS(2014), and European Project: 8911552(1989)

Subjects
Statistics and Probability, multinationality, L25, JEL: F - International Economics/F.F2 - International Factor Movements and International Business/F.F2.F23 - Multinational Firms • International Business, patents, Conditional efficiency, JEL: O - Economic Development, Innovation, Technological Change, and Growth/O.O3 - Innovation • Research and Development • Technological Change • Intellectual Property Rights/O.O3.O32 - Management of Technological Innovation and R&D, General Social Sciences, DEA modelling JEL classification O32, JEL: C - Mathematical and Quantitative Methods/C.C4 - Econometric and Statistical Methods: Special Topics/C.C4.C44 - Operations Research • Statistical Decision Theory, JEL: L - Industrial Organization/L.L2 - Firm Objectives, Organization, and Behavior/L.L2.L25 - Firm Performance: Size, Diversification, and Scope, DEA modelling, Multinationality, Patents, R&D productivity, [SHS.GESTION]Humanities and Social Sciences/Business administration, F23, C44
Abstract

This work explores the relationship between multinational R&D and innovation productivity among top corporate knowledge and R&D producers by adopting a twofold concept of internationalisation: (1) the firm’s degree of R&D internationalisation, and (2) the firm’s geographic diversification. We model the patent production process with an appropriate and robust conditional Data Envelopment Analysis (DEA) estimator, using a unique database of firms that matches financial indicators and patent information. Our results reinforce the fundamental role of internationalisation in the knowledge production process when the internationalisation process is properly and strategically managed. We interpret our empirical evidence through the theoretical lens of the learning theory of internationalisation, and we postulate that a high R&D intensity is a key driver to overcoming the challenges of internationalisation.

Published
2022

2. Infodemics: A new challenge for public health

Author

Sylvie C. Briand, Matteo Cinelli, Tim Nguyen, Rosamund Lewis, Dimitri Prybylski, Carlo M. Valensise, Vittoria Colizza, Alberto Eugenio Tozzi, Nicola Perra, Andrea Baronchelli, Michele Tizzoni, Fabiana Zollo, Antonio Scala, Tina Purnat, Christine Czerniak, Adam J. Kucharski, Akhona Tshangela, Lei Zhou, Walter Quattrociocchi, Organisation Mondiale de la Santé / World Health Organization Office (OMS / WHO), University of Ca’ Foscari [Venice, Italy], Centers for Disease Control and Prevention [Atlanta] (CDC), Centers for Disease Control and Prevention, Enrico Fermi Center for Study and Research | Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Institut Pierre Louis d'Epidémiologie et de Santé Publique (iPLESP), Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU), Bambino Gesù Children’s Hospital [Rome, Italy], University of Greenwich, City University of London, The Alan Turing Institute, Institute for Scientific Interchange Foundation [Turin, Italy] (ISI Foundation ), Institute for Complex Systems [Rome] (CNR - ISC), Consiglio Nazionale delle Ricerche [Roma] (CNR), London School of Hygiene and Tropical Medicine (LSHTM), Africa Centers for Disease Control and Prevention [Addis Ababa], Chinese Center for Disease Control and Prevention, Department of Informatics and System Sciences (Sapienza University of Rome), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), and HAL-SU, Gestionnaire

Subjects
Infodemic, Settore INF/01 - Informatica, Infodemics, Information Dissemination, SARS-CoV-2, [SDV]Life Sciences [q-bio], Research, Data Science, COVID-19, Complex Systems, Infodemics, Data Science, Complex Systems, General Biochemistry, Genetics and Molecular Biology, [SDV] Life Sciences [q-bio], RA0421, Commentary, Humans, Public Health, Epidemics
Abstract

International audience; The COVID-19 information epidemic, or "infodemic," demonstrates how unlimited access to information may confuse and influence behaviors during a health emergency. However, the study of infodemics is relatively new, and little is known about their relationship with epidemics management. Here, we discuss unresolved issues and propose research directions to enhance preparedness for future health crises.

Published
2021

3. A versatile and interoperable computational framework for the analysis and modeling of COVID-19 disease mechanisms

Author

Niarakis, Anna, Ostaszewski, Marek, Mazein, Alexander, Kuperstein, Inna, Kutmon, Martina, Gillespie, Marc, Funahashi, Akira, Acencio, Marcio, Hemedan, Ahmed, Aichem, Michael, Klein, Karsten, Czauderna, Tobias, Burtscher, Felicia, Yamada, Takahiro, Hiki, Yusuke, Hiroi, Noriko, Hu, Finterly, Pham, Nhung, Ehrhart, Friederike, Willighagen, Egon, Valdeolivas, Alberto, Dugourd, Aurelien, Messina, Francesco, Esteban-Medina, Marina, Pena-Chilet, Maria, Rian, Kinza, Soliman, Sylvain, Aghamiri, Sara, Puniya, Bhanwar, Naldi, Aurelien, Helikar, Tomas, Singh, Vidisha, Farinas Fernandez, Marco, Bermudez, Viviam, Tsirvouli, Eirini, Montagud, Arnau, Noel, Vincent, Ponce de Leon, Miguel, Maier, Dieter, Bauch, Angela, Gyori, Benjamin, Bachman, John, Luna, Agustin, Pinero, Janet, Furlong, Laura, Balaur, Irina, Rougny, Adrien, Jarosz, Yohan, Overall, Rupert, Phair, Robert, Perfetto, Livia, Matthews, Lisa, Rex, Devasahayam, Orlic-Milacic, Marija, Monraz Gomez, Luis, de Meulder, Bertrand, Ravel, Jean, Jassal, Bijay, Satagopam, Venkata, Wu, Guanming, Golebiewski, Martin, Gawron, Piotr, Calzone, Laurence, Beckmann, Jacques, Evelo, Chris, d'Eustachio, Peter, Schreiber, Falk, Saez-Rodriguez, Julio, Dopazo, Joaquin, Kuiper, Martin, Valencia, Alfonso, Wolkenhauer, Olaf, Kitano, Hiroaki, Barillot, Emmanuel, Auffray, Charles, Balling, Rudi, Schneider, Reinhard, Computational systems biology and optimization (Lifeware), Inria Saclay - Ile de France, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Laboratoire de recherche européen pour la polyarthrite rhumatoïde (GenHotel), Université d'Évry-Val-d'Essonne (UEVE)-Université Paris-Saclay, University of Luxembourg [Luxembourg], Cancer et génome: Bioinformatique, biostatistiques et épidémiologie d'un système complexe, Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut Curie [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM), Université Paris sciences et lettres (PSL), Maastricht Centre for Systems Biology [Maastricht] (MaCSBio), Maastricht University [Maastricht], Ontario Institute for Cancer Research [Canada] (OICR), Ontario Institute for Cancer Research, Keio University, Luxembourg Centre For Systems Biomedicine (LCSB), University of Konstanz, Hochschule Mittweida - University of Applied Sciences, Kanagawa Institute of Technology, Heidelberg University Hospital [Heidelberg], National Institute for Infectious Diseases 'Lazzaro Spallanzani', Hospital Universitario Virgen del Rocío [Sevilla], Biomedicine Institute of Sevilla [Seville, Spain], University of Nebraska–Lincoln, University of Nebraska System, Norwegian University of Science and Technology [Trondheim] (NTNU), Norwegian University of Science and Technology (NTNU), Barcelona Supercomputing Center - Centro Nacional de Supercomputacion (BSC - CNS), Harvard Medical School [Boston] (HMS), Universitat Pompeu Fabra [Barcelona] (UPF), National Institute of Advanced Industrial Science and Technology (AIST), Humboldt University Of Berlin, Integrative Bioinformatics Inc [Mountain View], Department of Informatics and System Sciences (Sapienza University of Rome), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), New York University Langone Medical Center (NYU Langone Medical Center), NYU System (NYU), Yenepoya University, Janet Piñero, Laura I. Furlong: IMI2-JU grants, resources which are composed of financial contributions from the European Union’s Horizon 2020 Research and Innovation Programme and EFPIA [GA: 777365 eTRANSAFE], and the EU H2020 Programme [GA:964537 RISKHUNT3R], Project 001-P-001647—Valorisation of EGA for Industry and Society funded by the European Regional Development Fund (ERDF) and Generalitat de Catalunya, and Institute of Health Carlos III (project IMPaCT-Data, exp. IMP/00019), co-funded by the European Union, European Regional Development Fund (ERDF, 'A way to make Europe').

Subjects
SARS-CoV-2, disease maps, systems biology, dynamic models, systems medicine, large-scale community effort, [INFO.INFO-BI]Computer Science [cs]/Bioinformatics [q-bio.QM], mechanistic models
Abstract

The COVID-19 Disease Map project is a large-scale community effort uniting 277 scientists from 130 Institutions around the globe. We use high-quality, mechanistic content describing SARS-CoV-2-host interactions and develop interoperable bioinformatic pipelines for novel target identification and drug repurposing. Community-driven and highly interdisciplinary, the project is collaborative and supports community standards, open access, and the FAIR data principles. The coordination of community work allowed for an impressive step forward in building interfaces between Systems Biology tools and platforms. Our framework links key molecules highlighted from broad omics data analysis and computational modeling to dysregulated pathways in a cell-, tissue- or patient-specific manner. We also employ text mining and AI-assisted analysis to identify potential drugs and drug targets and use topological analysis to reveal interesting structural features of the map. The proposed framework is versatile and expandable, offering a significant upgrade in the arsenal used to understand virus-host interactions and other complex pathologies.

Published
2022

4. On the domination number of $t$-constrained de Bruijn graphs

Author

Calamoneri, Tiziana, Monti, Angelo, Sinaimeri, Blerina, Department of Informatics and System Sciences (Sapienza University of Rome), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), Libera Università Internazionale degli Studi Sociali Guido Carli [Roma] (LUISS), Equipe de recherche européenne en algorithmique et biologie formelle et expérimentale (ERABLE), Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Inria Lyon, Institut National de Recherche en Informatique et en Automatique (Inria), and This work is partially supported by the following research projects: Sapienza University of Rome, projects: no. RM120172A3F313FE 'Measuring the similarity of biological and medical structures through graph isomorphism', no. RM11916B462574AD 'A deep study of phylogenetic tree reconciliations' and no. RM1181642702045E 'Comparative Analysis of Phylogenies

Subjects
Mathematics::Combinatorics, Domination number, de Bruijn graph, Kautz graph, General Computer Science, Mathematics::History and Overview, 05Cxx, 05C69, Kautz graph, Domination number, Nonlinear Sciences::Cellular Automata and Lattice Gases, Quantitative Biology::Genomics, Theoretical Computer Science, TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES, TheoryofComputation_LOGICSANDMEANINGSOFPROGRAMS, FOS: Mathematics, Discrete Mathematics and Combinatorics, Computer Science::Programming Languages, Mathematics - Combinatorics, [INFO]Computer Science [cs], Combinatorics (math.CO), de Bruijn graph, MathematicsofComputing_DISCRETEMATHEMATICS
Abstract

Motivated by the work on the domination number of directed de Bruijn graphs and some of its generalizations, in this paper we introduce a natural generalization of de Bruijn graphs (directed and undirected), namely $t$-constrained de Bruijn graphs, where $t$ is a positive integer, and then study the domination number of these graphs. Within the definition of $t$-constrained de Bruijn graphs, de Bruijn and Kautz graphs correspond to 1-constrained and 2-constrained de Bruijn graphs, respectively. This generalization inherits many structural properties of de Bruijn graphs and may have similar applications in interconnection networks or bioinformatics. We establish upper and lower bounds for the domination number on $t$-constrained de Bruijn graphs both in the directed and in the undirected case. These bounds are often very close and in some cases we are able to find the exact value.

Published
2022

5. Reduced Representation of Deformation Fields for Effective Non-rigid Shape Matching

Author

Sundararaman, Ramana, Marin, Riccardo, Rodola, Emanuele, Ovsjanikov, Maks, Sundararaman, Ramana, La Géometrie au Service du Numérique (GEOMERIX), Laboratoire d'informatique de l'École polytechnique [Palaiseau] (LIX), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)-Inria Saclay - Ile de France, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Paris (IP Paris), University of Tübingen, Department of Informatics and System Sciences (Sapienza University of Rome), and Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA)

Subjects
FOS: Computer and information sciences, Computer Science - Graphics, [INFO.INFO-CV] Computer Science [cs]/Computer Vision and Pattern Recognition [cs.CV], Computer Vision and Pattern Recognition (cs.CV), Computer Science - Computer Vision and Pattern Recognition, [INFO.INFO-CV]Computer Science [cs]/Computer Vision and Pattern Recognition [cs.CV], Graphics (cs.GR)
Abstract

International audience; In this work we present a novel approach for computing correspondences between non-rigid objects, by exploiting a reduced representation of deformation fields. Different from existing works that represent deformation fields by training a generalpurpose neural network, we advocate for an approximation based on mesh-free methods. By letting the network learn deformation parameters at a sparse set of positions in space (nodes), we reconstruct the continuous deformation field in a closed-form with guaranteed smoothness. With this reduction in degrees of freedom, we show significant improvement in terms of data-efficiency thus enabling limited supervision. Furthermore, our approximation provides direct access to first-order derivatives of deformation fields, which facilitates enforcing desirable regularization effectively. Our resulting model has high expressive power and is able to capture complex deformations. We illustrate its effectiveness through stateof-the-art results across multiple deformable shape matching benchmarks. Our code and data are publicly available at: https://github.com/Sentient07/ DeformationBasis.

Published
2022

6. A Hierarchical Framework for Collaborative Artificial Intelligence

Author

James L. Crowley, Joëlle Coutaz, Jasmin Grosinger, Javier Vazquez-Salceda, Cecilio Angulo, Alberto Sanfeliu, Luca Iocchi, Anthony G. Cohn, Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Multimodal Perception and Sociable Interaction (M-PSI), Laboratoire d'Informatique de Grenoble (LIG), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Örebro University, Universitat Politècnica de Catalunya [Barcelona] (UPC), Department of Informatics and System Sciences (Sapienza University of Rome), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), University of Leeds, ANR-19-P3IA-0003,MIAI,MIAI @ Grenoble Alpes(2019), European Project: 952026,EC:H2020 | RIA,HumanE AI Network(2020), European Project: AI4EU (grant agreement No. 825619), Universitat Politècnica de Catalunya. Departament de Ciències de la Computació, Universitat Politècnica de Catalunya. Departament d'Enginyeria de Sistemes, Automàtica i Informàtica Industrial, and Universitat Politècnica de Catalunya. VIS - Visió Artificial i Sistemes Intel·ligents

Subjects
FOS: Computer and information sciences, Informàtica::Intel·ligència artificial::Aprenentatge automàtic [Àrees temàtiques de la UPC], Computer Science - Artificial Intelligence, Computer Science - Human-Computer Interaction, [INFO.INFO-AI]Computer Science [cs]/Artificial Intelligence [cs.AI], Human-Computer Interaction (cs.HC), [INFO.INFO-IU]Computer Science [cs]/Ubiquitous Computing, Computer Science - Robotics, Agents intel·ligents (Programari), Machine learning, Robot sensing systems, Aprenentatge automàtic, Intelligent systems, [INFO.INFO-RB]Computer Science [cs]/Robotics [cs.RO], Computer Science - Multiagent Systems, [INFO.INFO-HC]Computer Science [cs]/Human-Computer Interaction [cs.HC], Intelligent agents (Computer software), Collaboration, Computer Science Applications, Behavioral sciences, Artificial Intelligence (cs.AI), Computational Theory and Mathematics, [INFO.INFO-MA]Computer Science [cs]/Multiagent Systems [cs.MA], Task analysis, Robots, Robotics (cs.RO), Software, Protocols, Multiagent Systems (cs.MA)
Abstract

International audience; We propose a hierarchical framework for collaborative intelligent systems. This framework organizes research challenges based on the nature of the collaborative activity and the information that must be shared, with each level building on capabilities provided by lower levels. We review research paradigms at each level, with a description of classical engineering-based approaches and modern alternatives based on machine learning, illustrated with a running example using a hypothetical personal service robot. We discuss cross-cutting issues that occur at all levels, focusing on the problem of communicating and sharing comprehension, the role of explanation and the social nature of collaboration. We conclude with a summary of research challenges and a discussion of the potential for economic and societal impact provided by technologies that enhance human abilities and empower people and society through collaboration with Intelligent Systems.; Nous proposons un cadre hiérarchique pour les systèmes intelligents collaboratifs. Ce cadre organise les défis de recherche en fonction de la nature de l'activité collaborative et des informations qui doivent être partagées, chaque niveau s'appuyant sur les capacités fournies par les niveaux inférieurs. Nous passons en revue les paradigmes de recherche à chaque niveau, avec une description des approches classiques basées sur l'ingénierie et des alternatives modernes basées sur l'apprentissage automatique, illustrées par un exemple courant utilisant un hypothétique robot de service personnel. Nous discutons des questions transversales qui se produisent à tous les niveaux, en nous concentrant sur le problème de la communication et du partage de la compréhension, le rôle de l'explication et la nature sociale de la collaboration. Nous concluons par un résumé des défis de la recherche et une discussion sur le potentiel d'impact économique et sociétal fourni par les technologies qui améliorent les capacités humaines et autonomisent les personnes et la société grâce à la collaboration avec les systèmes intelligents.

Published
2022
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7. Applications of a cloudsat-trmm and cloudsat-gpm satellite coincidence dataset

Author

Andrea Camplani, Giulia Panegrossi, Jean François Rysman, Ardeshir Ebtehaj, Daniele Casella, Sajad Vahedizade, Ramon Padullés, Guosheng Liu, Jie Gong, F. Joseph Turk, Norman B. Wood, Paolo Sanò, Lisa Milani, Mark S. Kulie, Sarah Ringerud, Randy J. Chase, National Aeronautics and Space Administration (US), California Institute of Technology (CALTECH), Earth Science System Interdisciplinary Center [College Park] (ESSIC), College of Computer, Mathematical, and Natural Sciences [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System-University of Maryland [College Park], University of Maryland System-University of Maryland System, NASA Goddard Space Flight Center (GSFC), Department of Informatics and System Sciences (Sapienza University of Rome), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], CNR Institute of Atmospheric Sciences and Climate (ISAC), Consiglio Nazionale delle Ricerche (CNR), University of Oklahoma (OU), Department of Civil, Environmental and Geo-Engineering [Minneapolis], University of Minnesota [Twin Cities] (UMN), University of Minnesota System-University of Minnesota System, National Oceanic and Atmospheric Administration (NOAA), Florida State University [Tallahassee] (FSU), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), University of Minnesota System, and University of Wisconsin-Madison

Subjects
010504 meteorology & atmospheric sciences, Science, 0211 other engineering and technologies, 02 engineering and technology, Precipitation, 01 natural sciences, Microphysics, law.invention, CloudSat, law, Cloud sat, Snow, Emissivity, Radar, TRMM, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Radiometer, Ice, 13. Climate action, GPM, ice, radar, radiometer, microwave, precipitation, snow, emissivity, microphysics, General Earth and Planetary Sciences, Environmental science, Satellite, Global Precipitation Measurement, Microwave
Abstract

The Global Precipitation Measurement (GPM) Dual-Frequency Precipitation Radar (DPR) (Ku-and Ka-band, or 14 and 35 GHz) provides the capability to resolve the precipitation structure under moderate to heavy precipitation conditions. In this manuscript, the use of near-coincident observations between GPM and the CloudSat Profiling Radar (CPR) (W-band, or 94 GHz) are demonstrated to extend the capability of representing light rain and cold-season precipitation from DPR and the GPM passive microwave constellation sensors. These unique triple-frequency data have opened up applications related to cold-season precipitation, ice microphysics, and light rainfall and surface emissivity effects., J.G. acknowledges the efforts by Ian Adams (NASA Goddard Space Flight Center) for support of airborne data collection during the IMPACTS campaign, and support from NASA grant 80NSSC20K0087.

Published
2021

8. String factorisations with maximum or minimum dimension

Author

Blerina Sinaimeri, Angelo Monti, Department of Informatics and System Sciences (Sapienza University of Rome), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), Equipe de recherche européenne en algorithmique et biologie formelle et expérimentale (ERABLE), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Baobab, Département PEGASE [LBBE] (PEGASE), Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS), and Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome]

Subjects
FOS: Computer and information sciences, General Computer Science, Dimension (graph theory), NP-hard problems, 0102 computer and information sciences, Computational Complexity (cs.CC), 01 natural sciences, Theoretical Computer Science, Combinatorics, 03 medical and health sciences, Integer, Factorization, Computer Science - Data Structures and Algorithms, Data Structures and Algorithms (cs.DS), [INFO]Computer Science [cs], Approximation algorithms, String factorisation, 030304 developmental biology, Mathematics, 0303 health sciences, String (computer science), Approximation algorithm, Computer Science - Computational Complexity, 010201 computation theory & mathematics, Bounded function
Abstract

In this paper we consider two problems concerning string factorisation. Specifically given a string w and an integer k find a factorisation of w where each factor has length bounded by k and has the minimum (the F-Min-D problem) or the maximum (the F-Max-D problem) number of different factors. The F-Min-D has been proved to be NP-hard even if k = 2 in [9] and for this case we provide a 3/2-approximation algorithm. The F-Max-D problem, up to our knowledge has not been considered in the literature. We show that this problem is NP-hard for any k ≥ 3 . In view of this we propose a 2-approximation algorithm (for any k) and an FPT algorithm w.r.t. parameter max ⁡ { k , | Σ | } .

Published
2020

9. Science Advice for Policy by European Academies A SUSTAINABLE FOOD SYSTEM FOR THE EUROPEAN UNION

Author

Jackson, Peter, Candel, Jeroen, Davies, Anna, DE VRIES, Hugo, Cristiane, Derani, Dragović-Uzelac, Verica, Hoel, Alf Håkon, Holm, Lotte, Morone, Piergiuseppe, Penker, Marianne, Rivera-Ferre, Marta Guadalupe, Spiewak, Ruta, Termeer, Katrien, Thogersen, John, Mathijs, Erik, University of Sheffield [Sheffield], Wageningen University and Research [Wageningen] (WUR), Trinity College Dublin, Ingénierie des Agro-polymères et Technologies Émergentes (UMR IATE), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Université de Montpellier (UM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Universidade Federal de Santa Catarina = Federal University of Santa Catarina [Florianópolis] (UFSC), University of Cambridge [UK] (CAM), University of Zagreb, University of Tromsø (UiT), IT University of Copenhagen, Department of Informatics and System Sciences (Sapienza University of Rome), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], University of Natural Resources and Life Sciences (BOKU), Open University of Catalonia [Barcelona], Institut of Mathematics - Polish Academy of Sciences (PAN), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Aarhus University [Aarhus], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Science Advice for Policy by European Academies, and Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Université de Montpellier (UM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)

Subjects
[SHS]Humanities and Social Sciences
Published
2020

10. In Silico Validation of MCID Platform for Monte Carlo-Based Voxel Dosimetry Applied to 90Y-Radioembolization of Liver Malignancies

Author

Marta Cremonesi, Salvatore Gallo, Alex Vergara Gil, Massimiliano Pacilio, Ivan Veronese, Alessia Milano, Riccardo Faccini, Nico Lanconelli, Enrico Fabrizi, Vergara Gil, Alex, Università cattolica del Sacro Cuore = Catholic University of the Sacred Heart [Roma] (Unicatt), Centre de Recherches en Cancérologie de Toulouse (CRCT), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Department of Informatics and System Sciences (Sapienza University of Rome), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), Istituto Europeo di Oncologia (IEO), Istituto Nazionale di Fisica Nucleare, Sezione di Milano (INFN), Istituto Nazionale di Fisica Nucleare (INFN), University of Bologna/Università di Bologna, Department of Physics [Roma La Sapienza], Istituto Nazionale di Fisica Nucleare, Sezione di Roma 3 (INFN, Sezione di Roma 3), Policlinico Umberto I [Rome, Italy], Università cattolica del Sacro Cuore [Roma] (Unicatt), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], University of Bologna, Milano, A., Gil, A.V., Fabrizi, E., Cremonesi, M., Veronese, I., Gallo, S., Lanconelli, N., Faccini, R., and Pacilio, M

Subjects
radioembolization, Monte Carlo-based dosimetry, Monte Carlo method, Partial volume, computer.software_genre, lcsh:Technology, 030218 nuclear medicine & medical imaging, lcsh:Chemistry, 03 medical and health sciences, 0302 clinical medicine, Voxel, Dosimetry, General Materials Science, Internal dosimetry, lcsh:QH301-705.5, Instrumentation, Mathematics, internal dosimetry, Fluid Flow and Transfer Processes, [SDV.IB] Life Sciences [q-bio]/Bioengineering, lcsh:T, Process Chemistry and Technology, General Engineering, Image segmentation, lcsh:QC1-999, Computer Science Applications, lcsh:Biology (General), lcsh:QD1-999, lcsh:TA1-2040, Homogeneous, 030220 oncology & carcinogenesis, Absorbed dose, [SDV.IB]Life Sciences [q-bio]/Bioengineering, lcsh:Engineering (General). Civil engineering (General), computer, lcsh:Physics, Biomedical engineering
Abstract

International audience; The aim was the validation of a platform for internal dosimetry, named MCID, based on patient-specific images and direct Monte Carlo (MC) simulations, for radioembolization of liver tumors with 90Y-labeled microspheres. CT of real patients were used to create voxelized phantoms with different density and activity maps. SPECT acquisitions were simulated by the SIMIND MC code. Input macros for the GATE/Geant4 code were generated by MCID, loading coregistered morphological and functional images and performing image segmentation. The dosimetric results obtained from the direct MC simulations and from conventional MIRD approach at both organ and voxel level, in condition of homogeneous tissues, were compared, obtaining differences of about 0.3% and within 3%, respectively, whereas differences increased (up to 14%) introducing tissue heterogeneities in phantoms. Mean absorbed dose for spherical regions of different sizes (10 mm ≤ r ≤ 30 mm) from MC code and from OLINDA/EXM were also compared obtaining differences varying in the range 7–69%, which decreased to 2–9% after correcting for partial volume effects (PVEs) from imaging, confirming that differences were mostly due to PVEs, even though a still high difference for the smallest sphere suggested possible source description mismatching. This study validated the MCID platform, which allows the fast implementation of a patient-specific GATE simulation, avoiding complex and time-consuming manual coding. It also points out the relevance of personalized dosimetry, accounting for inhomogeneities, in order to avoid absorbed dose misestimations.

Published
2020

11. Knowledge Graphs

Author

Axel Polleres, Lukas Schmelzeisen, Axel-Cyrille Ngonga Ngomo, Roberto Navigli, Steffen Staab, Eva Blomqvist, Claudio Gutierrez, José Emilio Labra Gayo, Juan F. Sequeda, Sabrina Kirrane, Aidan Hogan, Sabbir M. Rashid, Michael Cochez, Claudia d'Amato, Antoine Zimmermann, Sebastian Neumaier, Gerard de Melo, Anisa Rula, Millennium Institute for Foundational Research on Data (IMFD), Pontificia Universidad Católica de Chile (UC), Linköping University (LIU), Vrije Universiteit Brussel (VUB), Discovery Lab, Polytechnic University of Bari, Rutgers University System (Rutgers), WU Vienna, Universidad de Oviedo [Oviedo], Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Universität Paderborn (UPB), Tetherless World Constellation, Rensselaer Polytechnic Institute (RPI), University of Milano, University of Bonn, Universität Stuttgart [Stuttgart], data.world, École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT), Laboratoire d'Informatique, de Modélisation et d'Optimisation des Systèmes (LIMOS), Ecole Nationale Supérieure des Mines de St Etienne-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national polytechnique Clermont Auvergne (INP Clermont Auvergne), Université Clermont Auvergne (UCA)-Université Clermont Auvergne (UCA), Institut Henri Fayol (FAYOL-ENSMSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Département Informatique et systèmes intelligents ( FAYOL-ENSMSE), Ecole Nationale Supérieure des Mines de St Etienne, Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), Universität Bonn = University of Bonn, Ecole Nationale Supérieure des Mines de St Etienne (ENSM ST-ETIENNE)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national polytechnique Clermont Auvergne (INP Clermont Auvergne), Ecole Nationale Supérieure des Mines de St Etienne (ENSM ST-ETIENNE), Department of Computer and Information Science - Linköping University, Computer Systems Section - Vrije Universiteit Amsterdam, Vrije Universiteit Amsterdam [Amsterdam] (VU), University of Bari Aldo Moro (UNIBA), Department of Informatics and System Sciences (Sapienza University of Rome), Università degli Studi di Milano-Bicocca [Milano] (UNIMIB), Universität Koblenz-Landau [Koblenz], University of Southampton, Laboratoire Hubert Curien [Saint Etienne] (LHC), Institut d'Optique Graduate School (IOGS)-Université Jean Monnet [Saint-Étienne] (UJM)-Centre National de la Recherche Scientifique (CNRS), Département Informatique et systèmes intelligents (FAYOL-ENSMSE), Mines Saint-Etienne, Breuil, Florent, Hogan, A, Blomqvist, E, Cochez, M, D'Amato, C, Melo, G, Gutierrez, C, Kirrane, S, Gayo, J, Navigli, R, Neumaier, S, Ngomo, A, Polleres, A, Rashid, S, Rula, A, Schmelzeisen, L, Sequeda, J, Staab, S, and Zimmermann, A

Subjects
FOS: Computer and information sciences, Computer Science - Machine Learning, Graph databases, Theoretical computer science, Computer science, 505002 Data protection, Ontologie, 02 engineering and technology, computer.software_genre, Data modeling, [INFO.INFO-AI]Computer Science [cs]/Artificial Intelligence [cs.AI], Machine Learning (cs.LG), 102001 Artificial intelligence, 0202 electrical engineering, electronic engineering, information engineering, Graph query language, Graph algorithms, 102015 Informationssysteme, Computer Sciences, Graph algorithm, Shape, Contrast (statistics), Databases (cs.DB), Graph neural network, Embeddings, Graph (abstract data type), Graph neural networks, Graph query languages, Knowledge graphs, Ontologies, Rule mining, Shapes, 020201 artificial intelligence & image processing, [INFO.INFO-MO] Computer Science [cs]/Modeling and Simulation, Embedding, [INFO.INFO-AI] Computer Science [cs]/Artificial Intelligence [cs.AI], General Computer Science, Computer Science - Artificial Intelligence, [INFO] Computer Science [cs], Theoretical Computer Science, 502050 Wirtschaftsinformatik, Computer Science - Databases, 020204 information systems, 505002 Datenschutz, Knowledge graphs, graph databases, graph query languages, shapes, ontologies, graph algorithms, embeddings, graph neural networks, rule mining, 102015 Information systems, [INFO]Computer Science [cs], graph databases, graph query languages, shapes, ontologies, graph algorithms, embeddings, graph neural networks, rule mining, Knowledge graph, Graph database, 502050 Business informatics, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, Datavetenskap (datalogi), Artificial Intelligence (cs.AI), computer
Abstract

In this paper we provide a comprehensive introduction to knowledge graphs, which have recently garnered significant attention from both industry and academia in scenarios that require exploiting diverse, dynamic, large-scale collections of data. After some opening remarks, we motivate and contrast various graph-based data models and query languages that are used for knowledge graphs. We discuss the roles of schema, identity, and context in knowledge graphs. We explain how knowledge can be represented and extracted using a combination of deductive and inductive techniques. We summarise methods for the creation, enrichment, quality assessment, refinement, and publication of knowledge graphs. We provide an overview of prominent open knowledge graphs and enterprise knowledge graphs, their applications, and how they use the aforementioned techniques. We conclude with high-level future research directions for knowledge graphs., Comment: Revision from v5: Correcting errata from previous version for entailment/models, and some other minor typos

Published
2020
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12. Stress assessment by combining neurophysiological signals and radio communications of air traffic controllers

Author

Stefano Bonelli, Uğur Turhan, Géraud Granger, Raïlane Benhacene, Fabrice Drogoul, Martina Ragosta, Birsen Acikel, Jean-Paul Imbert, Paola Tomasello, Vincenzo Ronca, Fabio Babiloni, Gianluca Borghini, Silvia Orlandi, Gianluca Di Flumeri, Andrea Bandini, Ali Ozan, Nicolina Sciaraffa, Pietro Aricò, Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Università degli Studi di Firenze = University of Florence [Firenze] (UNIFI), Department of Informatics and System Sciences (Sapienza University of Rome), DeepBlue, Kastamonu University, Eskişehir Technical University, Ecole Nationale de l'Aviation Civile (ENAC), EUROCONTROL, Department of Physiology and Pharmacology [Rome], Borghini G., Bandini A., Orlandi S., Di Flumeri G., Arico P., Sciaraffa N., Ronca V., Bonelli S., Ragosta M., Tomasello P., Turhan U., Acikel B., Ozan A., Imbert J.P., Granger G., Benhacene R., Drogoul F., and Babiloni F.

Subjects
0301 basic medicine, medicine.medical_specialty, Brain activity and meditation, brain, speech, Alpha (ethology), Poison control, Audiology, Stress, beta rhythm, 03 medical and health sciences, 0302 clinical medicine, Rhythm, Control theory, humans, aviation, neurophysiology, medicine, Beta Rhythm, Mathematics, Skin, [SCCO.NEUR]Cognitive science/Neuroscience, Radio communication, Electroencephalography, Neurophysiology, Air traffic control, 030104 developmental biology, Electronic mail, Feature extraction, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, 030217 neurology & neurosurgery, Human
Abstract

International audience; Air Traffic Control (ATC) has been classified as the fourth most stressful job. In this regard, sixteen controllers were asked to perform ecological ATC simulation during which behavioral (Radio Communications with pilots - RCs), subjective (stress perception) and neurophysiological signals (brain activity and skin conductance - SC) were collected. All the considered parameters reported significant changes under high stress conditions. In particular, the theta, alpha, and beta brain rhythms increased significantly (all p

Published
2020

13. Fully Dynamic Consistent Facility Location

Author

Vincent Cohen-Addad, Niklas Hjuler, Nikos Parotsidis, David Saulpic, Chris Schwiegelshohn, Recherche Opérationnelle (RO), LIP6, Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS), University of Copenhagen = Københavns Universitet (KU), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL), Department of Informatics and System Sciences (Sapienza University of Rome), and Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome]

Subjects
streams, clustering, [INFO.INFO-DS]Computer Science [cs]/Data Structures and Algorithms [cs.DS], Dynamic Algorithms, Clustering
Abstract

We consider classic clustering problems in fully dynamic data streams, where data elements can be both inserted and deleted. In this context, there are several important parameters: (1) the quality of the solution after each insertion or deletion, (2) the time it takes to update the solution, and (3) how different consecutive solutions are. The question of obtaining efficient algorithms in this context for facility location, k-median and k- means has been raised in a recent paper by Hubert-Chan et al. [WWW'18] and also appears as a natural follow-up on the online model with recourse studied by Lattanzi and Vassilvitskii [ICML'17] (i.e.: in insertion-only streams). In this paper, we focus on general metric spaces and mainly on the facility location problem. We give an arguably simple algorithm that maintains a constant factor approximation, with \(O(n\log n)\)update time, and total recourse \(O(n)\). This improves over the naive algorithm which consists in recomputing a solution after each update and that can take up to \(O(n^2)\)update time, and\(O(n^2)\) total recourse. Our bounds are nearly optimal: in general metric space, inserting a point takes \(O(n)\)times to describe the distances to other points, and we give a simple lower bound of \(O(n)\)for the recourse. Moreover, we generalize this result for the k- medians and k-means problems: our algorithms maintain a constant factor approximation in \(O(n+k^2)\)time per update. We complement our analysis with experiments showing that the cost of the solution maintained by our algorithm at any time t is very close to the cost of a solution obtained by quickly recomputing a solution from scratch at time t while having a much better running time.

Published
2019
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14. System thermal-hydraulic modelling of the phénix dissymmetric test benchmark

Author

Adam Kraus, A. Del Nevo, J. W. Thomas, Acacia J. Brunett, N. Girault, Gianfranco Caruso, Xiaoye Wang, Fabio Giannetti, F. Alcaro, B. Grosjean, Vincenzo Narcisi, A. Gerschenfeld, Department of Informatics and System Sciences (Sapienza University of Rome), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Italian National agency for new technologies, Energy and sustainable economic development [Frascati] (ENEA), Nuclear Research and Consultancy Group, Karlsruhe Institute of Technology (KIT), Argonne National Laboratory [Lemont] (ANL), Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Université Paris-Saclay, Narcisi, V., Giannetti, F., Del Nevo, A., Alcaro, F., Wang, X., Kraus, A., Brunett, A., Thomas, J., Girault, N., Grosjean, B., Caruso, G., and Gerschenfeld, A.

Subjects
Nuclear and High Energy Physics, Liquid metal, Source code, Computer science, 020209 energy, media_common.quotation_subject, Nuclear engineering, Shutdown, 02 engineering and technology, 01 natural sciences, 7. Clean energy, Phénix, system thermal-hydraulics, sodium cooled reactors, SESAME, dissymmetric test, 010305 fluids & plasmas, Set (abstract data type), Thermal hydraulics, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, General Materials Science, Safety, Risk, Reliability and Quality, Waste Management and Disposal, media_common, [PHYS]Physics [physics], Mechanical Engineering, Frame (networking), Experimental data, Nuclear Energy and Engineering, Benchmark (computing)
Abstract

International audience; Phénix is a French pool-type sodium-cooled prototype reactor; before the definitive shutdown, occurred in 2009, a final set of experimental tests are carried out in order to increase the knowledge on the operation and the safety aspect of the pool-type liquid metal-cooled reactors. One of the experiments was the Dissymmetric End-of-Life Test which was selected for the validation benchmark activity in the frame of SESAME project. The computer code validation plays a key role in the safety assessment of the innovative nuclear reactors and the Phénix dissymmetric test provides useful experimental data to verify the computer codes capability in the asymmetric thermal-hydraulic behaviour into a pool-type liquid metal-cooled reactor. This paper shows the comparison of the outcomes obtained with six different System Thermal-Hydraulic (STH) codes RELAP5-3D©, SPECTRA, ATHLET, SAS4A/SASSYS-1, ASTEC-Na and CATHARE. The nodalization scheme of the reactor was individually achieved by the participants; during the development of the thermal-hydraulic model, the pool nodalization methodology had a special attention in order to investigate the capability of the STH codes to reproduce the dissymmetric effects which occur in each loop and into pools, caused by the azimuthal asymmetry of the boundary conditions. The modelling methodology of the participants is discussed and the main results are compared in this paper to obtain useful guide lines for the future modelling of innovative liquid metal pool-type reactors. © 2019 Elsevier B.V.

Published
2019

15. Online Reciprocal Recommendation with Theoretical Performance Guarantees

Author

Vitale, Fabio, Parotsidis, Nikos, Gentile, Claudio, Department of Informatics and System Sciences (Sapienza University of Rome), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Machine Learning in Information Networks (MAGNET), Inria Lille - Nord Europe, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189 (CRIStAL), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS), University of Rome 'Tor Vergeta', Google Inc, Research at Google, Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), and Università degli Studi di Roma Tor Vergata [Roma]

Subjects
FOS: Computer and information sciences, Computer Science - Learning, [INFO.INFO-LG]Computer Science [cs]/Machine Learning [cs.LG], Statistics - Machine Learning, Machine Learning (stat.ML), [INFO]Computer Science [cs], Machine Learning (cs.LG)
Abstract

International audience; A reciprocal recommendation problem is one where the goal of learning is not just to predict a user's preference towards a passive item (e.g., a book), but to recommend the targeted user on one side another user from the other side such that a mutual interest between the two exists. The problem thus is sharply different from the more traditional items-to-users recommendation, since a good match requires meeting the preferences at both sides. We initiate a rigorous theoretical investigation of the reciprocal recommendation task in a specific framework of sequential learning. We point out general limitations, formulate reasonable assumptions enabling effective learning and, under these assumptions, we design and analyze a computationally efficient algorithm that uncovers mutual likes at a pace comparable to that achieved by a clairvoyant algorithm knowing all user preferences in advance. Finally, we validate our algorithm against synthetic and real-world datasets, showing improved empirical performance over simple baselines.

Published
2018

16. Co-divergence and tree topology

Author

Angelo Monti, Tiziana Calamoneri, Blerina Sinaimeri, Department of Informatics and System Sciences (Sapienza University of Rome), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), Equipe de recherche européenne en algorithmique et biologie formelle et expérimentale (ERABLE), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Baobab, Département PEGASE [LBBE] (PEGASE), Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS), and Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome]

Subjects
[INFO.INFO-DS]Computer Science [cs]/Data Structures and Algorithms [cs.DS], Network topology, 01 natural sciences, 010305 fluids & plasmas, Combinatorics, Evolution, Molecular, 03 medical and health sciences, 0103 physical sciences, Subsequence, Quantitative Biology::Populations and Evolution, Animals, Humans, Equivalence (formal languages), reconciliations, Time complexity, Phylogeny, 030304 developmental biology, Mathematics, 0303 health sciences, Phylogenetic tree, Models, Genetic, Applied Mathematics, Approximation algorithm, Computational Biology, caterpillars, Agricultural and Biological Sciences (miscellaneous), Tree structure, Modeling and Simulation, co-phylogeny, [INFO.INFO-BI]Computer Science [cs]/Bioinformatics [q-bio.QM], Heuristics, Algorithms
Abstract

In reconstructing the common evolutionary history of hosts and parasites, the current method of choice is the phylogenetic tree reconciliation. In this model, we are given a host tree H, a parasite tree P, and a function [Formula: see text] mapping the leaves of P to the leaves of H and the goal is to find, under some biologically motivated constraints, a reconciliation, that is a function from the vertices of P to the vertices of H that respects [Formula: see text] and allows the identification of biological events such as co-speciation, duplication and host switch. The maximum co-divergence problem consists in finding the maximum number of co-speciations in a reconciliation. This problem is NP-hard for arbitrary phylogenetic trees and no approximation algorithm is known. In this paper we consider the influence of tree topology on the maximum co-divergence problem. In particular we focus on a particular tree structure, namely caterpillar, and show that-in this case-the heuristics that are mostly used in the literature provide solutions that can be arbitrarily far from the optimal value. Then, we prove that finding the max co-divergence is equivalent to compute the maximum length of a subsequence with certain properties of a given permutation. This equivalence leads to two consequences: (1) it shows that we can compute efficiently in polynomial time the optimal time-feasible reconciliation and (2) it can be used to understand how much the tree topology influences the value of the maximum number of co-speciations.

Published
2018

17. Improved functional mappings via product preservation

Author

Dorian Nogneng, Michael M. Bronstein, Maks Ovsjanikov, Simone Melzi, Umberto Castellani, Emanuele Rodolà, Laboratoire d'informatique de l'École polytechnique [Palaiseau] (LIX), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Department of Computer Science [Verona] (UNIVR | DI), University of Verona (UNIVR), Department of Informatics and System Sciences (Sapienza University of Rome), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Università della Svizzera italiana = University of Italian Switzerland (USI), Nogneng, D, Melzi, S, Rodolá, E, Castellani, U, Bronstein, M, and Ovsjanikov, M

Subjects
Pointwise, Shape analysi, Basis (linear algebra), Computational complexity theory, Computer science, shape analysis, [INFO.INFO-CV]Computer Science [cs]/Computer Vision and Pattern Recognition [cs.CV], Software Engineering, products preservation, 020207 software engineering, Basis function, 02 engineering and technology, Function (mathematics), functional mapping, Computer Graphics and Computer-Aided Design, Computational geometry, 0202 electrical engineering, electronic engineering, information engineering, 0801 Artificial Intelligence and Image Processing, Shape analysis, Theory of computation, 020201 artificial intelligence & image processing, Representation (mathematics), Linear combination, Algorithm, Vector space
Abstract

International audience; In this paper, we consider the problem of information transfer across shapes and propose an extension to the widely used functional map representation. Our main observation is that in addition to the vector space structure of the functional spaces, which has been heavily exploited in the functional map framework, the functional algebra (i.e., the ability to take pointwise products of functions) can significantly extend the power of this framework. Equipped with this observation, we show how to improve one of the key applications of functional maps, namely transferring real-valued functions without conversion to point-to-point correspondences. We demonstrate through extensive experiments that by decomposing a given function into a linear combination consisting not only of basis functions but also of their pointwise products, both the representation power and the quality of the function transfer can be improved significantly. Our modification, while computationally simple, allows us to achieve higher transfer accuracy while keeping the size of the basis and the functional map fixed. We also analyze the computational complexity of optimally representing functions through linear combinations of products in a given basis and prove NP-completeness in some general cases. Finally, we argue that the use of function products can have a wide-reaching effect in extending the power of functional maps in a variety of applications, in particular by enabling the transfer of high-frequency functions without changing the representation size or complexity.

Published
2018

18. On the Local Structure of Stable Clustering Instances

Author

Chris Schwiegelshohn, Vincent Cohen-Addad, University of Copenhagen = Københavns Universitet (KU), Department of Informatics and System Sciences (Sapienza University of Rome), and Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome]

Subjects
Computational Geometry (cs.CG), FOS: Computer and information sciences, Mathematical optimization, Correlation clustering, [INFO.INFO-DS]Computer Science [cs]/Data Structures and Algorithms [cs.DS], 0102 computer and information sciences, 02 engineering and technology, 01 natural sciences, Machine Learning (cs.LG), Local optimum, CURE data clustering algorithm, Computer Science - Data Structures and Algorithms, 0202 electrical engineering, electronic engineering, information engineering, Data Structures and Algorithms (cs.DS), Local search (optimization), Cluster analysis, ComputingMilieux_MISCELLANEOUS, Mathematics, business.industry, Computer Science (all), Constrained clustering, Approximation algorithm, Computer Science - Learning, 010201 computation theory & mathematics, Canopy clustering algorithm, Computer Science - Computational Geometry, 020201 artificial intelligence & image processing, business
Abstract

We study the classic k-median and k-means clustering objectives in the beyond-worst-case scenario. We consider three well-studied notions of structured data that aim at characterizing real-world inputs:• Distribution Stability (introduced by Awasthi, Blum, and Sheffet, FOCS 2010)• Spectral Separability (introduced by Kumar and Kannan, FOCS 2010)• Perturbation Resilience (introduced by Bilu and Linial, ICS 2010)We prove structural results showing that inputs satisfying at least one of the conditions are inherently local. Namely, for any such input, any local optimum is close both in term of structure and in term of objective value to the global optima.As a corollary we obtain that the widely-used Local Search algorithm has strong performance guarantees for both the tasks of recovering the underlying optimal clustering and obtaining a clustering of small cost. This is a significant step toward understanding the success of local search heuristics in clustering applications.

Published
2017

19. GUB Covers and Power-Indexed formulations for Wireless Network Design

Author

Antonio Sassano, Carlo Mannino, Fabio D'Andreagiovanni, Centre National de la Recherche Scientifique (CNRS), Information and Communication Technology [Oslo] (SINTEF - ICT), Stiftelsen for INdustriell og TEknisk Forskning Digital [Trondheim] (SINTEF Digital), Department of Informatics and System Sciences (Sapienza University of Rome), and Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome]

Subjects
FOS: Computer and information sciences, Mathematical optimization, Discrete Mathematics (cs.DM), Strategy and Management, 0211 other engineering and technologies, 02 engineering and technology, Management Science and Operations Research, Upper and lower bounds, Set (abstract data type), Computer Science - Networking and Internet Architecture, [INFO.INFO-NI]Computer Science [cs]/Networking and Internet Architecture [cs.NI], 0-1 linear programming, strong formulation, Computer Science - Data Structures and Algorithms, 0202 electrical engineering, electronic engineering, information engineering, FOS: Mathematics, [INFO]Computer Science [cs], Data Structures and Algorithms (cs.DS), Special case, Finite set, Mathematics - Optimization and Control, ComputingMilieux_MISCELLANEOUS, Mathematics, Wireless Network Design, 0-1 Linear Programming, GUB Cover Inequalities, gub cover inequalities, power discretization, wireless network design, Networking and Internet Architecture (cs.NI), 021103 operations research, Wireless network, 020206 networking & telecommunications, Extension (predicate logic), Cover (topology), Knapsack problem, Optimization and Control (math.OC), [MATH.MATH-OC]Mathematics [math]/Optimization and Control [math.OC], Computer Science - Discrete Mathematics
Abstract

We propose a pure 0-1 formulation for the wireless network design problem, i.e. the problem of configuring a set of transmitters to provide service coverage to a set of receivers. In contrast with classical mixed integer formulations, where power emissions are represented by continuous variables, we consider only a finite set of powers values. This has two major advantages: it better fits the usual practice and eliminates the sources of numerical problems which heavily affect continuous models. A crucial ingredient of our approach is an effective basic formulation for the single knapsack problem representing the coverage condition of a receiver. This formulation is based on the GUB cover inequalities introduced by Wolsey (1990) and its core is an extension of the exact formulation of the GUB knapsack polytope with two GUB constraints. This special case corresponds to the very common practical situation where only one major interferer is present. We assess the effectiveness of our formulation by comprehensive computational results over realistic instances of two typical technologies, namely WiMAX and DVB-T., Comment: This is the authors' final version of the paper published in Management Science 59(1), 142-156, 2013. DOI: 10.1287/mnsc.1120.1571. The final publication is available at INFORMS via http://pubsonline.informs.org/doi/abs/10.1287/mnsc.1120.1571

Published
2017
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20. Negative Cycle Separation in Wireless Network Design

Author

Antonio Sassano, Carlo Mannino, Fabio D'Andreagiovanni, Zuse Institute Berlin (ZIB), Information and Communication Technology [Oslo] (SINTEF - ICT), Stiftelsen for INdustriell og TEknisk Forskning Digital [Trondheim] (SINTEF Digital), Department of Informatics and System Sciences (Sapienza University of Rome), and Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome]

Subjects
FOS: Computer and information sciences, Mathematical optimization, Discrete Mathematics (cs.DM), Computer science, media_common.quotation_subject, Separation (aeronautics), 0211 other engineering and technologies, 02 engineering and technology, Computer Science - Networking and Internet Architecture, [INFO.INFO-NI]Computer Science [cs]/Networking and Internet Architecture [cs.NI], 020204 information systems, Computer Science - Data Structures and Algorithms, 0202 electrical engineering, electronic engineering, information engineering, FOS: Mathematics, Quality (business), Data Structures and Algorithms (cs.DS), Mathematics - Optimization and Control, ComputingMilieux_MISCELLANEOUS, media_common, Networking and Internet Architecture (cs.NI), 021103 operations research, Wireless network, [INFO.INFO-RO]Computer Science [cs]/Operations Research [cs.RO], Negative cycle, Optimization and Control (math.OC), [MATH.MATH-OC]Mathematics [math]/Optimization and Control [math.OC], Computer Science - Discrete Mathematics
Abstract

The Wireless Network Design Problem (WND) consists in choosing values of radio-electrical parameters of transmitters of a wireless network, to maximize network coverage. We present a pure 0-1 Linear Programming formulation for the WND that may contain an exponential number of constraints. Violated inequalities of this formulation are hard to separate both theoretically and in practice. However, a relevant subset of such inequalities can be separated more efficiently in practice and can be used to strengthen classical MILP formulations for the WND. Preliminary computational experience confirms the effectiveness of our new technique both in terms of quality of solutions found and provided bounds., Comment: This is the authors' final version of the paper published in Pahl J., Reiners T., Voss S. (eds), Network Optimization - INOC 2011. Lecture Notes in Computer Science, vol 6701, pp. 51-56. Springer, Berlin, Heidelberg, 2011, DOI: 10.1007/978-3-642-21527-8_7. The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-21527-8_7

Published
2017
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21. Dynamic centrifuge tests on multilayer soil columns: setup and shear wave propagation

Author

BRETSCHNEIDER, Alberto, Escoffier, Sandra, Lenti, Luca, MARTINO, Salvatore, Séismes et Vibrations (IFSTTAR/GERS/SV), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Communauté Université Paris-Est, Department of Informatics and System Sciences (Sapienza University of Rome), and Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome]

Subjects
CENTRIFUGEUSE GEOTECHNIQUE, [SPI]Engineering Sciences [physics], SOL, MULTICOUCHE, PROPAGATION DES ONDES, MODELISATION PHYSIQUE, CENTRIFUGATION
Abstract

EUROFUGE 2016, NANTES, FRANCE, 01-/06/2016 - 03/06/2016; Soil heterogeneity plays a relevant role in shear wave propagation. This paper reports the setup procedure and accelerometers outputs of dynamic centrifuge tests performed on multilayer soil columns composed by sand and clay. A homogeneous sand column has also been tested under the same experimental conditions in order to have a benchmark. The multilayer soil columns are composed by an original technique; strengths and weakness of this technique are discussed. The tests have been performed at a centrifuge acceleration of 55g. The earthquake signal applied to the model has a peak ground acceleration of 0.05g. Time histories observed at different depths in multilayers are compared with those of the homogenous sand column. The results put in evidence the role played in these tests by the presence of multilayer soils in terms of signal amplifications, modifications of the frequency content and triggering of coseismic effects.

Published
2016

22. On the Troll-Trust Model for Edge Sign Prediction in Social Networks

Author

Le Falher, Géraud, Cesa-Bianchi, Nicolò, Gentile, Claudio, Vitale, Fabio, Machine Learning in Information Networks (MAGNET), Inria Lille - Nord Europe, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189 (CRIStAL), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Scienze dell'Informazione [Milano], Università degli Studi di Milano [Milano] (UNIMI), Universitá degli Studi dell’Insubria, Aalto University School of Science and Technology [Aalto, Finland], INRIA Lille, Università degli Studi di Milano = University of Milan (UNIMI), Universitá degli Studi dell’Insubria = University of Insubria [Varese] (Uninsubria), Department of Informatics and System Sciences (Sapienza University of Rome), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], University of Lille, University of Milan, University of Insubria, Department of Computer Science, Aalto-yliopisto, and Aalto University

Subjects
Social and Information Networks (cs.SI), FOS: Computer and information sciences, Computer Science - Learning, Computer Science - Social and Information Networks, Machine Learning (cs.LG), [INFO.INFO-AI]Computer Science [cs]/Artificial Intelligence [cs.AI]
Abstract

In the problem of edge sign prediction, we are given a directed graph (representing a social network), and our task is to predict the binary labels of the edges (i.e., the positive or negative nature of the social relationships). Many successful heuristics for this problem are based on the troll-trust features, estimating at each node the fraction of outgoing and incoming positive/negative edges. We show that these heuristics can be understood, and rigorously analyzed, as approximators to the Bayes optimal classifier for a simple probabilistic model of the edge labels. We then show that the maximum likelihood estimator for this model approximately corresponds to the predictions of a Label Propagation algorithm run on a transformed version of the original social graph. Extensive experiments on a number of real-world datasets show that this algorithm is competitive against state-of-the-art classifiers in terms of both accuracy and scalability. Finally, we show that troll-trust features can also be used to derive online learning algorithms which have theoretical guarantees even when edges are adversarially labeled., Comment: v5: accepted to AISTATS 2017

Published
2016

23. Stochastic Analysis of the $k$-Server Problem on the Circle

Author

Eli Upfal, Clément Dombry, Aris Anagnostopoulos, Ioannis Kontoyiannis, Nadine Guillotin-Plantard, Department of Informatics and System Sciences (Sapienza University of Rome), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Laboratoire de Mathématiques et Applications (LMA-Poitiers), Université de Poitiers-Centre National de la Recherche Scientifique (CNRS), Institut Camille Jordan [Villeurbanne] (ICJ), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université Jean Monnet [Saint-Étienne] (UJM)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Department of Informatics [Athens] (CS-AUEB), Mobile Multimedia Laboratory [Athens], Athens University of Economics and Business (AUEB)-Athens University of Economics and Business (AUEB), Department of Computer Science (Brown University), Brown University, Drmota, Michael and Gittenberger, Bernhard, and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Independent and identically distributed random variables, Mathematical optimization, Theoretical computer science, General Computer Science, K-server problem, [INFO.INFO-DS]Computer Science [cs]/Data Structures and Algorithms [cs.DS], [INFO.INFO-DS] Computer Science [cs]/Data Structures and Algorithms [cs.DS], Arbitrary distribution, [INFO.INFO-DM]Computer Science [cs]/Discrete Mathematics [cs.DM], [INFO.INFO-CG]Computer Science [cs]/Computational Geometry [cs.CG], Theoretical Computer Science, $k$-server, Server, [MATH.MATH-CO]Mathematics [math]/Combinatorics [math.CO], Convergence (routing), Discrete Mathematics and Combinatorics, Probabilistic analysis of algorithms, Computer Science::Operating Systems, Mathematics, Stochastic process, Process (computing), probabilistic analysis, on-line algorithms, [MATH.MATH-CO] Mathematics [math]/Combinatorics [math.CO], [INFO.INFO-DM] Computer Science [cs]/Discrete Mathematics [cs.DM], [INFO.INFO-CG] Computer Science [cs]/Computational Geometry [cs.CG]
Abstract

We consider a stochastic version of the $k$-server problem in which $k$ servers move on a circle to satisfy stochastically generated requests. The requests are independent and identically distributed according to an arbitrary distribution on a circle, which is either discrete or continuous. The cost of serving a request is the distance that a server needs to move to reach the request. The goal is to minimize the steady-state expected cost induced by the requests. We study the performance of a greedy strategy, focusing, in particular, on its convergence properties and the interplay between the discrete and continuous versions of the process.

Published
2010

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