References of "First made available on ORBi"
     in
Bookmark and Share    
Full Text
See detailThe Date of Plutarch's De Tranquillitate Animi
Demulder, Bram ULiege

E-print/Working paper (in press)

Detailed reference viewed: 56 (7 ULiège)
Full Text
See detailDe linguae latinae usu, Actes du 13e Colloque international de Linguistique latine, Bruxelles et Liège, 4-9 avril 2005
Longrée, Dominique ULiege; Lenoble, Muriel

E-print/Working paper (in press)

Detailed reference viewed: 89 (16 ULiège)
Full Text
See detailQue sont les matrimoines ? Projet d'exposition
Franck, Thomas ULiege

E-print/Working paper (2021)

Detailed reference viewed: 43 (4 ULiège)
Full Text
See detailFlash-back sur l'Agrégation de l'Enseignement Supérieur en mathématiques à l'Université de Liège
Bair, Jacques ULiege

E-print/Working paper (2021)

De nos jours, le diplôme universitaire le plus élevé possible en mathématiques est le doctorat. Mais, par le passé existaient des grades supérieurs, à savoir ceux d’Agrégation de l’Enseignement Supérieur ... [more ▼]

De nos jours, le diplôme universitaire le plus élevé possible en mathématiques est le doctorat. Mais, par le passé existaient des grades supérieurs, à savoir ceux d’Agrégation de l’Enseignement Supérieur et de Doctorat Spécial, désignés en abrégé par les acronymes AES et DS respectivement. Dans cet article, nous présentons succinctement ces deux épreuves, esquissons une étude historique générale sur ces diplômes, et plus spécialement sur celui de l’agrégation de l’enseignement supérieur en mathématiques à l’Université de Liège. Nous dressons ensuite la liste de tous les diplômés AES ou DS en mathématiques à l’Université de Liège de 1931 à 2004 (ce qui correspond à la période pendant laquelle l’AES existait officiellement en Belgique), puis nous nous attardons plus spécialement sur un cas particulier, à savoir celui de l’auteur de ces lignes: nous retraçons la chronique des trois épreuves, ce qui nous permet de rappeler le règlement alors en application (en 1984-985). Nous terminons ce travail par cinq annexes composées de documents et de photos d'époque. [less ▲]

Detailed reference viewed: 32 (1 ULiège)
Full Text
See detailLa vérité sur le « Made in Belgium » de l’e-commerce alimentaire
Ozer, Pierre ULiege

E-print/Working paper (2021)

Detailed reference viewed: 114 (5 ULiège)
Full Text
See detailInvest Smarter... All my Tweets on the Art & Science of Internet-Based Investing
Choffray, Jean-Marie ULiege

E-print/Working paper (2021)

“Invest smarter…” I started this project five years ago. After hundreds of hours of reading, thinking and writing, here they are: “All my Tweets on The Art & Science of Internet-Based Investing”, as most ... [more ▼]

“Invest smarter…” I started this project five years ago. After hundreds of hours of reading, thinking and writing, here they are: “All my Tweets on The Art & Science of Internet-Based Investing”, as most of them appear in my Twitter archive. My initial goal was to share my observations, analyses, and conclusions as to the evolution of the world and the behavior of the markets over a period of several years – which happened to correspond with the Presidency of Donald J. Trump. Also, I wanted to organize and illustrate the key heuristics that I learned, often painfully, as a modest investor. Needless to say that I never expected to experience a full-scale pandemic, and its accompanying episode of mass hysteria. A very real, and global, Black Swan! My main conclusion today is that our world hasn’t changed that much over time. It’s almost like it was stuck in a “steady state”, or some kind of “eternal present”. Human beings continue to “lie, cheat and steal”… (US Secretary of State Mike Pompeo). De La Bruyère (1645-1696) was perfectly right in his “Characters”, and the observations of Erasmus (1467-1536) in “Praise of Folly” are more relevant than ever: “Let us not speak of the evil which man does to man: he ruins him, imprisons him, dishonors him, tortures him, sets traps for him, betrays him; to enumerate everything, with outrages, lawsuits, swindles, would be to count the grains of sand.” So, I think that any investor could still succeed and prosper in today’s digital markets while following the advice of Henry Clews (1836-1923) in “Fifty Years in Wall Street”. As to me…, without a doubt, I am no Warren Buffett :-)! Feel free to disagree with what you will read in the following pages, and don’t hesitate to develop your own theory of investing as you allocate capital and observe results – a painful and solitary exercise. Success is at that price! Fortunately, based on what I achieved during these hectic years, it shouldn’t be hard for you to do better... “Bon vent”… in the fog of the markets! [less ▲]

Detailed reference viewed: 613 (106 ULiège)
Full Text
Peer Reviewed
See detailGYM-ANM: Reinforcement learning environments for active network management tasks in electricity distribution systems
Henry, Robin; Ernst, Damien ULiege

E-print/Working paper (2021)

Active network management (ANM) of electricity distribution networks include many complex stochastic sequential optimization problems. These problems need to be solved for integrating renewable energies ... [more ▼]

Active network management (ANM) of electricity distribution networks include many complex stochastic sequential optimization problems. These problems need to be solved for integrating renewable energies and distributed storage into future electrical grids. In this work, we introduce Gym-ANM, a framework for designing reinforcement learning (RL) environments that model ANM tasks in electricity distribution networks. These environments provide new playgrounds for RL research in the management of electricity networks that do not require an extensive knowledge of the underlying dynamics of such systems. Along with this work, we are releasing an implementation of an introductory toy-environment, ANM6-Easy, designed to emphasize common challenges in ANM. We also show that state-of-the-art RL algorithms can already achieve good performance on ANM6-Easy when compared against a model predictive control (MPC) approach. Finally, we provide guidelines to create new Gym-ANM environments differing in terms of (a) the distribution network topology and parameters, (b) the observation space, (c) the modelling of the stochastic processes present in the system, and (d) a set of hyperparameters influencing the reward signal. Gym-ANM can be downloaded at https://github.com/robinhenry/gym-anm. [less ▲]

Detailed reference viewed: 56 (13 ULiège)
Full Text
See detailDistance de collaboration
Bair, Jacques ULiege

E-print/Working paper (2021)

L’illustre mathématicien Paul Erdős est quelquefois appelé le « pionnier des mathématiques de la collaboration ». Cette appellation suggère une petite étude présentant un concept général mesurant en ... [more ▼]

L’illustre mathématicien Paul Erdős est quelquefois appelé le « pionnier des mathématiques de la collaboration ». Cette appellation suggère une petite étude présentant un concept général mesurant en quelque sorte le degré de collaboration entre des mathématiciens-chercheurs. [less ▲]

Detailed reference viewed: 27 (2 ULiège)
Full Text
Peer Reviewed
See detailRemote renewable hubs for carbon-neutral synthetic fuel production
Berger, Mathias ULiege; Radu, David-Constantin ULiege; Detienne, Ghislain et al

E-print/Working paper (2021)

This paper studies the economics of carbon-neutral synthetic fuel production from renewable electricity in remote areas where high-quality renewable resources are abundant. To this end, a graph-based ... [more ▼]

This paper studies the economics of carbon-neutral synthetic fuel production from renewable electricity in remote areas where high-quality renewable resources are abundant. To this end, a graph-based optimisation modelling framework directly applicable to the strategic planning of remote renewable energy supply chains is proposed. More precisely, a graph abstraction of planning problems is introduced, wherein nodes can be viewed as optimisation subproblems with their own parameters, variables, constraints and local objective, and typically represent a subsystem such as a technology, a plant or a process. Edges, on the other hand, express the connectivity between subsystems. The framework is leveraged to study the economics of carbon-neutral synthetic methane production from solar and wind energy in North Africa and its delivery to Northwestern European markets. The full supply chain is modelled in an integrated fashion, which makes it possible to accurately capture the interaction between various technologies on hourly time scales. Results suggest that the cost of synthetic methane production and delivery would be slightly under 200€/MWh and 150€/MWh by 2030 for a system supplying 100 TWh (higher heating value) annually that relies on solar photovoltaic plants alone and a combination of solar photovoltaic and wind power plants, respectively, assuming a uniform weighted average cost of capital of 7%. The cost difference between these system configurations mostly stems from higher investments in technologies providing flexibility required to balance the system in the solar-driven configuration. Synthetic methane costs would drop to roughly 124€/MWh and 87€/MWh, respectively, if financing costs were zero and only technology costs were taken into account. Prospects for cost reductions are also discussed, and options that would enable such reductions are reviewed. [less ▲]

Detailed reference viewed: 437 (26 ULiège)
Full Text
See detailTémoignages d'universitaires liégeois en liaison avec la guerre de la mathématique moderne
Bair, Jacques ULiege

E-print/Working paper (2021)

L'enseignement des mathématiques en Belgique a connu essentiellement deux querelles portant sur les programmes suivis dans le secondaire: la "Guerre entre Infinicoles et Infinifuges" au dix-neuvième ... [more ▼]

L'enseignement des mathématiques en Belgique a connu essentiellement deux querelles portant sur les programmes suivis dans le secondaire: la "Guerre entre Infinicoles et Infinifuges" au dix-neuvième siècle, et la "Guerre de la Mathématique Moderne" au vingtième siècle. Ces deux épisodes ont fait l'objet de nombreuses études historiques. Dans ce travail, nous allons nous intéresser exclusivement à la "guerre de la mathématique moderne" qui s'est déroulée dans les années 1960 et 1970 à propos d'une réforme radicale préconisant d'introduire les concepts d'ensembles et de structures mathématiques dans le secondaire (et même dans le primaire et en maternelle). Cette étude est focalisée sur l'action de mathématiciens de l'Université de Liège autour de cette réforme, ce qui est apparemment l'objet de peu de travaux historiques. Et pourtant, cette querelle fut ``ardente''. Nous en apportons des témoignages datant de l'époque concernée. [less ▲]

Detailed reference viewed: 74 (2 ULiège)
Full Text
See detailGraph-Based Optimization Modeling Language: A Tutorial
Berger, Mathias ULiege; Bolland, Adrien ULiege; Miftari, Bardhyl et al

E-print/Working paper (2021)

This paper introduces the graph-based optimization modeling language (GBOML), which enables the easy implementation of a broad class of structured linear programs typically found in applications ranging ... [more ▼]

This paper introduces the graph-based optimization modeling language (GBOML), which enables the easy implementation of a broad class of structured linear programs typically found in applications ranging from energy system planning to supply chain management. More precisely, the language is particularly well-suited for representing problems involving the optimization of discrete-time dynamical systems over a finite time horizon and possessing a block decomposable structure that can be encoded by a sparse connected graph. The language combines elements from both algebraic and object-oriented modeling languages in order to facilitate problem encoding and post-processing. This document discusses the abstract problem class that can be represented using the modeling language, details its grammar and provides two relevant examples of applications. The first example deals with the deployment of a microgrid system, while the second example focuses on the design and analysis of remote carbon-neutral fuel supply chains. [less ▲]

Detailed reference viewed: 164 (35 ULiège)
Full Text
Peer Reviewed
See detailThe nature of consciousness in anesthesia
Montupil, Javier ULiege; Martial, Charlotte ULiege; Gosseries, Olivia ULiege et al

E-print/Working paper (2021)

Detailed reference viewed: 36 (4 ULiège)
Full Text
See detailCRÉER DES SAÉ - Guide de soutien à la création de situations d’apprentissage et d’évaluation (SAÉ) en contexte d’APC1,2
Georges, François ULiege; Poumay, Marianne ULiege

E-print/Working paper (2020)

Guide d'aide à la rédaction de Situations d'Apprentissage et d'Évaluation. Le guide propose trois portes d'entrée : La première (en p. 2) reprend succinctement quelques éléments théoriques relatifs à la ... [more ▼]

Guide d'aide à la rédaction de Situations d'Apprentissage et d'Évaluation. Le guide propose trois portes d'entrée : La première (en p. 2) reprend succinctement quelques éléments théoriques relatifs à la tâche authentique, ce qu’elle est et son intérêt. La seconde (en p. 6) est destinée à l’équipe enseignante désireuse d’entrer directement en action.Elle l’accompagne pas à pas dans la conception d’une SAÉ. La troisième (en p. 14) est une grille destinée à évaluer la qualité d’une SAÉ. L’outil s’adresse auxenseignants chevronnés qui souhaitent s’assurer que leur SAÉ rencontre les critères d’une tâche authentique susceptible de soutenir le développement de compétences. [less ▲]

Detailed reference viewed: 408 (39 ULiège)
Full Text
See detailUn modèle relatif à la TSUS (Transition Secondaire-Université en Statistique)
Bair, Jacques ULiege

E-print/Working paper (2020)

Nous nous intéressons à l'enseignement de la statistique descriptive au niveau de la TSU (Transition Secondaire-Université). Nous présentons un modèle didactique sous forme d'un graphe dont les sommets ... [more ▼]

Nous nous intéressons à l'enseignement de la statistique descriptive au niveau de la TSU (Transition Secondaire-Université). Nous présentons un modèle didactique sous forme d'un graphe dont les sommets (ou pôles) sont relatifs aux savoirs en jeu (c'est-à-dire au savoir savant, au savoir à enseigner, au savoir enseigné et au savoir appris), tandis que les arcs traduisent l'influence directe d'un pôle sur un autre. Les degrés des divers sommets peuvent fournir intuitivement un indicateur relatif à l'importance des différents pôles dans le processus d'enseignement. [less ▲]

Detailed reference viewed: 30 (2 ULiège)
Full Text
See detailLes citoyens et leur patrimoine local en Wallonie
Pepe, Lauriano ULiege; Schmitz, Serge ULiege

E-print/Working paper (2020)

Depuis 1976, l'asbl "Qualité village Wallonie" travaille à la sauvegarde du patrimoine rural local et a constaté au cours de ces dernières décennies des changements quant à l’intérêt des Wallons pour leur ... [more ▼]

Depuis 1976, l'asbl "Qualité village Wallonie" travaille à la sauvegarde du patrimoine rural local et a constaté au cours de ces dernières décennies des changements quant à l’intérêt des Wallons pour leur patrimoine. Ce document interroge le rôle actuel du patrimoine local et sa place dans les préoccupations citoyennes en présentant les résultats d'une enquête menée auprès de 1088 Wallons. [less ▲]

Detailed reference viewed: 115 (26 ULiège)
Full Text
See detailIndustry 4.0: An empirical analysis of its adoption in Wallonia
Paseyro Mayol, Joaquin ULiege; Gautier, Axel ULiege; Neysen, Nicolas ULiege

E-print/Working paper (2020)

This paper studies the factors influencing the adoption of digital technologies in the manufacturing sector; the so called Industry 4.0 phenomenon. We focus on the adoption of three particular ... [more ▼]

This paper studies the factors influencing the adoption of digital technologies in the manufacturing sector; the so called Industry 4.0 phenomenon. We focus on the adoption of three particular technologies (Predictive Maintenance, Smart Production and Advanced Planning) in the Belgian region of Wallonia. In line with the claims of related qualitative studies, our findings suggest that smaller firms, which have a more restricted access to financial resources, are less prone to adopt these technologies. Our results are compatible with the notion that more digitally mature firms are more prone to be adopters. Moreover, we do not find evidence supporting the claim that more profitable firms are more likely to be adopters. Finally, we present indicative evidence regarding the efficacy of the regional governmental program which aimed to increase the diffusion of Industry 4.0. [less ▲]

Detailed reference viewed: 57 (11 ULiège)
Full Text
See detailThe Firm Size Distribution in Belgium
Artige, Lionel ULiege; Bignandi, Sousso ULiege

E-print/Working paper (2020)

The shape of the firm size distribution (FSD) looks similar in all market economies but its approximation by a parametric distribution, a necessary information to build a general model of firm dynamics ... [more ▼]

The shape of the firm size distribution (FSD) looks similar in all market economies but its approximation by a parametric distribution, a necessary information to build a general model of firm dynamics, remains much debated. In this paper, we use an exclusive comprehensive database on Belgian firms. We show that the lognormal distribution is a better approximation of the empirical FSD than the power law distribution. This result holds true at the aggregate, sectoral and regional levels. [less ▲]

Detailed reference viewed: 90 (51 ULiège)
Full Text
See detailNutritional status of inmates in the Central Prison of Mbuji-Mayi, Democratic Republic of Congo
De Coninck, Gérard; Okenge Ngongo, Leon; Ilunga Ilunga, Félicien et al

E-print/Working paper (2020)

Background: The nutritional situation in prisons of developing countries and the health status of inmates remain a major human rights concern. The objective of the study was to assess the nutritional ... [more ▼]

Background: The nutritional situation in prisons of developing countries and the health status of inmates remain a major human rights concern. The objective of the study was to assess the nutritional status of inmates jailed in a prison of the Democratic Republic of Congo (DRC). Methods: This cross-sectional study was conducted over a 4-month period in the Central Prison of Mbuji-Mayi, DRC. Three hundred inmates were selected according to the Malnutrition Universal Screening Tool (MUST). Severe malnutrition was defined according to Buzby index and Nutritional Risk Index (NRI). Data were analyzed by logistic regression. Results: The inmates were aged between 18 and 70 years and primarily males (88.7%). Of them, 24% were suffering from severe malnutrition and 62% of moderate malnutrition as based on the NRI. At the time of study, 88% of inmates were incarcerated for more than 6 months. Multivariate logistic regression analysis showed that factors independently associated with severe malnutrition were incarceration of more than 6 months (OR=5.1; 95% CI [1.5-17.4]), origin of food (prison vs. family or NGO) (OR=4.7; 95% CI [1.6-13.8]) but also presence of tuberculosis, human immunodeficiency virus and/or intestinal infections (OR=2.6; 95% CI [1.4-4.7]). Conclusions: The nutritional situation in the Central Prison of Mbuji-Mayi is precarious. There is urgent need to supply enough nutrient-rich food to improve health of inmates. [less ▲]

Detailed reference viewed: 53 (2 ULiège)
Full Text
See detailThe norito-granitic zone of Puntervoll-Lia (Rogaland anorthosite province, S. Norway): evolution of a genetic model
Duchesne, Jean-Clair ULiege

E-print/Working paper (2020)

The norito-granitic zone is a thin septum of highly deformed banded rocks squeezed between two anorthosite massifs, the Egersund-Ogna (EGOG) and the Håland massifs. The dominant lithologies are a norito ... [more ▼]

The norito-granitic zone is a thin septum of highly deformed banded rocks squeezed between two anorthosite massifs, the Egersund-Ogna (EGOG) and the Håland massifs. The dominant lithologies are a norito-anorthosite association gradationally passing into a norito-granitic association. A first genetic model was proposed in which a norite intruded in the foliated margin of the EGOG anorthosite was migmatitized and metasomatically transformed into an anorthosite. This model was not confirmed by later studies and finally the norito-anorthosite association was considered as a particular facies of the anorthosite margin. New studies of the Glypstad septum between EGOG and the Bjerkreim-Sokndal layered intrusion reveal that the norito-granitic association results from the deformation of a magma in which anatectic melts were mingled with a high-alumina basalt, parental to the EGOG anorthosite. [less ▲]

Detailed reference viewed: 49 (10 ULiège)
Full Text
See detailInfluence of model formulation on the critical morphological acceleration factor: an analytical study
Dewals, Benjamin ULiege; Archambeau, Pierre ULiege; Pirotton, Michel ULiege et al

E-print/Working paper (2020)

The morphological acceleration factor (Morfac) has been used for over two decades to speed-up long term morphodynamic simulations. However, the Morfac values are usually set heuristically and hardly any ... [more ▼]

The morphological acceleration factor (Morfac) has been used for over two decades to speed-up long term morphodynamic simulations. However, the Morfac values are usually set heuristically and hardly any study investigated theoretically the critical Morfac value leading to a predefined level of accuracy. In this research, we evaluated theoretically the critical Morfac value from the analysis of the amplitude and phase errors induced by the use of Morfac. While the few existing studies focused only on relatively low Froude numbers and a single mathematical formulation of the morphodynamic model, we consider here a significantly wider range of Froude numbers, including supercritical flow, and we compare four different model formulations. We show that the model formulation leading to the highest critical Morfac values for subcritical flow is not the same as for supercritical flow. [less ▲]

Detailed reference viewed: 48 (9 ULiège)
Full Text
See detailAnalogies entre deux querelles relatives à l'enseignement des mathématiques en Belgique
Bair, Jacques ULiege

E-print/Working paper (2020)

Depuis la création du royaume de Belgique, l’enseignement de base des mathématiques a connu dans ce pays deux importantes querelles : la guerre entre infinicoles et infinifuges au début du 19e siècle et ... [more ▼]

Depuis la création du royaume de Belgique, l’enseignement de base des mathématiques a connu dans ce pays deux importantes querelles : la guerre entre infinicoles et infinifuges au début du 19e siècle et la guerre des mathématiques modernes durant la seconde moitié du 20e siècle. Ces deux épisodes historiques présentent des analogies qui vont être analysées dans cet article. Sont en présence deux clans avec des visions différentes sur la nécessité ou non de renouveler le savoir à enseigner, de modifier l’approche didactique, d’accorder de l’importance à l’aspect utilitaire de la discipline. Au surplus, dans les deux cas, le camp des conservateurs et des adeptes d’un enseignement simple et axé sur les applications était emmené avec ardeur par un liégeois, professeur à l’Université de Liège ; on pourrait y voir une manifestation de l’« esprit liégeois ». [less ▲]

Detailed reference viewed: 50 (6 ULiège)
Full Text
See detailRéactivation de l’idée d’une « Taxe GAFA » dans le contexte (post-)CORONA
Nollet, Aymeric ULiege

E-print/Working paper (2020)

Detailed reference viewed: 19 (1 ULiège)
Full Text
See detailEre « après COVID-19 » : les publicités promeuvent des voitures toujours plus polluantes.
Ozer, Pierre ULiege

E-print/Working paper (2020)

Detailed reference viewed: 108 (19 ULiège)
Full Text
See detailBank risk-taking and Competition: Does efficiency matter? Evidence from African Banking Industry
Matabaro, Borauzima Luc ULiege; Muller, Aline ULiege

E-print/Working paper (2020)

We contribute to the existing literature on the nexus between competition and risk taking in the banking industry by emphasizing the role of efficiency. We test a modified Martinez-Miera and Repullo (2010 ... [more ▼]

We contribute to the existing literature on the nexus between competition and risk taking in the banking industry by emphasizing the role of efficiency. We test a modified Martinez-Miera and Repullo (2010)’s model which uses a single factor Vasiceck specification to analyze default’s probability for a set of loans. Our results confirm that efficiency plays a non-monotonic role in the competition-risk relationship. On top of confirming the U-shape relationship between competition and risk-taking, our reveal that banks with high and low efficiency take more risk than those with average efficiency ones. We also find that size, diversification index, macroeconomic, institutional play a key role in competition-risking-taking process in African banking industry. Besides, African Cross-border banks display less riskiness and may accordingly enhance financial stability. These results are stable across different robustness checks including alternative measures of competition and specifications and consequently serve for regulatory policies especially for providing very stringent regulatory frameworks to mitigate the implications of competition in terms of financial stability. [less ▲]

Detailed reference viewed: 58 (4 ULiège)
Full Text
See detailRédiger le référentiel de compétences du Bachelor Universitaire de Technologie - Guide d'accompagnement à la rédaction du référentiel de compétences du B.U.T. en contexte d'APC
Georges, François ULiege; Poumay, Marianne ULiege

E-print/Working paper (2020)

Ce guide vise à donner des éléments méthodologiques pour la conception et l’écriture du référentiel de compétences du Bachelor Universitaire de Technologie et des parcours le structurant. En Approche Par ... [more ▼]

Ce guide vise à donner des éléments méthodologiques pour la conception et l’écriture du référentiel de compétences du Bachelor Universitaire de Technologie et des parcours le structurant. En Approche Par Compétence (APC), le référentiel de compétences constitue la colonne vertébrale de la formation. Il aide à prendre les décisions tant de structuration du programme que de mise en œuvre de celui-ci. Il permet aussi une communication transparente avec les étudiants et les partenaires socio-professionnels quant aux visées et attendus du programme. Pour aboutir à un référentiel de compétences qui oriente le programme de formation et guide sa mise en oeuvre, le guide appelle à préciser cinq éléments pour chacune des compétences, qui constituent cinq étapes de rédaction du référentiel (compétences, composantes essentielles, familles de situations, niveaux et approrentissages critiques). Il illustre chacune des étapes par quelques exemples de formulation issus de référentiels existants. [less ▲]

Detailed reference viewed: 196 (23 ULiège)
Full Text
See detailDes infinicoles liégeois
Bair, Jacques ULiege

E-print/Working paper (2020)

L’histoire de l’analyse mathématique est à la fois longue et riche, puisque cette théorie n’a cessé de se développer depuis l’Antiquité en empruntant essentiellement deux voies différentes selon que le ... [more ▼]

L’histoire de l’analyse mathématique est à la fois longue et riche, puisque cette théorie n’a cessé de se développer depuis l’Antiquité en empruntant essentiellement deux voies différentes selon que le concept d’infiniment petit est utilisé ou au contraire proscrit. Les mathématiciens qui exploitent des infiniment petits sont appelés « infinicoles » ; cet adjectif est formé du mot « infini » suivi du suffixe « cole » venant du verbe latin « colere » dont une traduction en français peut être « cultiver ». Ceux qui rejettent les infinitésimaux sont nommés des « infinifuges », car le suffixe « fuge » provient du substantif latin « fuga » signifiant « fuite », de sorte que les infinifuges évitent ou fuient les infiniment. Notre travail est consacré à certains infinicoles qui ne rejettent pas une conception actuelle de l’infini. Plus précisément, nous nous intéressons aux infinicoles qui ont fait appel, dans certains de leurs écrits, à des infiniment petits au sens des pionniers de l’analyse classique, c’est-à-dire aux infinicoles qui n’utilisent pas la théorie weierstrassienne des limites, mais qui recourent plutôt à ce que l’on appelle aujourd’hui l’analyse non standard. Parmi ceux-ci, nous retenons uniquement des liégeois, c’est-à-dire des mathématiciens qui ont habité dans la province de Liège pendant au moins une partie de leur carrière professionnelle. Ils ont tous travaillé, à un moment de leur carrière, à l’Université de Liège (sauf le plus ancien d’entre eux parce que l’Université n’existait pas encore de son temps). Ainsi, neuf mathématiciens sont succinctement présentés. Une liste exhaustive de leur production dans ce domaine figure dans une bibliographie détaillée. [less ▲]

Detailed reference viewed: 37 (4 ULiège)
Full Text
See detailLa sagesse des marchés
Choffray, Jean-Marie ULiege

E-print/Working paper (2020)

Soyons précis ! Ne pas croire dans le SARS-CoV-2 – comme seul facteur explicatif de la réalité à laquelle nous sommes confrontés –, n’implique pas d’en nier l’existence ; de ne pas respecter la douleur de ... [more ▼]

Soyons précis ! Ne pas croire dans le SARS-CoV-2 – comme seul facteur explicatif de la réalité à laquelle nous sommes confrontés –, n’implique pas d’en nier l’existence ; de ne pas respecter la douleur de celles et ceux qu’il touche ; de manquer de respect pour le courage et la générosité exemplaires des personnels impliqués ; ou d’en contester les inévitables et sévères conséquences sur le fonctionnement de la société. Tout au contraire, cette posture intellectuelle entraîne la nécessité d’en analyser, scrupuleusement et scientifiquement, toutes les dimensions et implications. La diversité, la complexité et la réflexivité de ces dernières invitent à la patience et à la plus grande circonspection. C’est à ce niveau que les marchés financiers offrent une plateforme technologique et un laboratoire expérimental exceptionnels d’observation, d’analyse et de prévision. Leur sagesse actuelle est un appel à la raison, au comportement responsable, à la vigilance civique, et au retour progressif, mais résolu, à la vie sociale ! [less ▲]

Detailed reference viewed: 334 (40 ULiège)
Full Text
Peer Reviewed
See detailVers ma réussite en Bac 1 : Positionnement, pistes d'évaluation et de régulation d'un dispositif propédeutique transversal en blended learning
Dupont, Bruno ULiege; Cocinas Garcia, Amélie ULiege

E-print/Working paper (2020)

Ce travail en cours détaille le passage d'un dispositif du présentiel au blended learning d'un dispositif propédeutique de soutien à la réussite en Bac 1 à la Haute École de la Ville de Liège. Sont ... [more ▼]

Ce travail en cours détaille le passage d'un dispositif du présentiel au blended learning d'un dispositif propédeutique de soutien à la réussite en Bac 1 à la Haute École de la Ville de Liège. Sont détaillées le développement du projet, son état actuel, ainsi que ses perspectives de régulation et d'évaluation. [less ▲]

Detailed reference viewed: 62 (9 ULiège)
Full Text
See detailOral Chloroquine treatment for COVID-19 infection. Available data from literature & field practices on April 20, 2020 (ver 1.8)
Jamoulle, Marc ULiege

E-print/Working paper (2020)

Publications addressing the treatment of COVID-19 by Hydroxychloroquine available on April 20, 2020. gathered sinc March 13, 2020. This compilation does not constitute a recommendation to use the HCQ in ... [more ▼]

Publications addressing the treatment of COVID-19 by Hydroxychloroquine available on April 20, 2020. gathered sinc March 13, 2020. This compilation does not constitute a recommendation to use the HCQ in the treatment of Covid-19 [less ▲]

Detailed reference viewed: 440 (21 ULiège)
Full Text
See detailModèles mathématiques et confinement
Rigo, Michel ULiege

E-print/Working paper (2020)

En cette période de confinement dû à la crise sanitaire provoquée par le SARS-CoV-2 mieux connu comme Coronavirus, le virus responsable du COVID-19, je voulais comprendre les modèles utilisés par les ... [more ▼]

En cette période de confinement dû à la crise sanitaire provoquée par le SARS-CoV-2 mieux connu comme Coronavirus, le virus responsable du COVID-19, je voulais comprendre les modèles utilisés par les virologues et épidémiologistes du monde entier. Par la même occasion, je m'en vais vous expliquer ces courbes que l'on trouve à longueur de journée dans les média et que l'on souhaite "aplatir". Habitué à la vulgarisation mathématique, je ne suis pourtant pas un spécialiste des mathématiques appliquées et de la modélisation. Il ne nécessite a priori que très peu de connaissances mathématiques : un peu de bon sens et la manipulation des proportions. Il devrait être accessible dès la 4e année de l'enseignement secondaire. [less ▲]

Detailed reference viewed: 3758 (53 ULiège)
Full Text
Peer Reviewed
See detailA Deep Reinforcement Learning Framework for Continuous Intraday Market Bidding
Boukas, Ioannis ULiege; Ernst, Damien ULiege; Théate, Thibaut ULiege et al

E-print/Working paper (2020)

The large integration of variable energy resources is expected to shift a large part of the energy exchanges closer to real-time, where more accurate forecasts are available. In this context, the short ... [more ▼]

The large integration of variable energy resources is expected to shift a large part of the energy exchanges closer to real-time, where more accurate forecasts are available. In this context, the short-term electricity markets and in particular the intraday market are considered a suitable trading floor for these exchanges to occur. A key component for the successful renewable energy sources integration is the usage of energy storage. In this paper, we propose a novel modelling framework for the strategic participation of energy storage in the European continuous intraday market where exchanges occur through a centralized order book. The goal of the storage device operator is the maximization of the profits received over the entire trading horizon, while taking into account the operational constraints of the unit. The sequential decision-making problem of trading in the intraday market is modelled as a Markov Decision Process. An asynchronous version of the fitted Q iteration algorithm is chosen for solving this problem due to its sample efficiency. The large and variable number of the existing orders in the order book motivates the use of high-level actions and an alternative state representation. Historical data are used for the generation of a large number of artificial trajectories in order to address exploration issues during the learning process. The resulting policy is back-tested and compared against a benchmark strategy that is the current industrial standard. Results indicate that the agent converges to a policy that achieves in average higher total revenues than the benchmark strategy. [less ▲]

Detailed reference viewed: 867 (89 ULiège)
Full Text
See detailA Real-Time Receding-Horizon Transmission Voltages Control using Sensitivity Matrix and Bias
Glavic, Mevludin ULiege

E-print/Working paper (2020)

In this paper, a simplified multi-step recedinghorizon controller is introduced to control the violations in transmission voltages and stop developing long-term voltage instabilities. The system model is ... [more ▼]

In this paper, a simplified multi-step recedinghorizon controller is introduced to control the violations in transmission voltages and stop developing long-term voltage instabilities. The system model is derived from the context of quadratic dynamic matrix control and is represented as a set of linear constraints derived from sensitivity analysis and bias terms acting as modelling error corrector. Resulting multi-step optimization is highly structured convex quadratic programming problem for which reliable standard codes are available. The goal of proposed controller is to achieve high performances with simplified system model relying on reliable optimization solver. The Nordic32 test system is used for evaluating the performance of proposed controller and its comparison with existing closely related approaches focusing on minimization of expensive controls (load shedding). [less ▲]

Detailed reference viewed: 32 (1 ULiège)
Full Text
See detailSalon de l’auto 2020 : des voitures « toujours plus durables et plus propres ». Vraiment ?
Ozer, Pierre ULiege

E-print/Working paper (2020)

Detailed reference viewed: 242 (11 ULiège)
Full Text
See detailMentors’ Motives and Mentoring Functions Associated with Mentoring of Social and Commercial New Ventures
Yusubova, Ayna ULiege; Xhauflair, Virginie ULiege; Pichault, François ULiege

E-print/Working paper (2020)

Although mentoring services have been advanced as an important mechanism of incubator and accelerator programs for overcoming the resource constraints of commercial and social new ventures, it has ... [more ▼]

Although mentoring services have been advanced as an important mechanism of incubator and accelerator programs for overcoming the resource constraints of commercial and social new ventures, it has traditionally focused on the entrepreneur's perspective and neglected the mentor's perspective, particularly the examination of mentors' motivations and behavior. The present study employed a qualitative research strategy for examining mentoring from the perspective of the mentor. A total of 18 mentors from accelerator and incubator programs located in Belgium participated in in-depth interviews regarding their experience as a mentor. Given the distinctive and similar dimensions of social and commercial new ventures, this study reveals a more comprehensive view of various mentor motives related to the provision of functions, identifying similarities and distinctions between both types of new ventures mentoring motivations and functional differences of these types of motivation. Implications of the findings and suggestions for future research are presented. [less ▲]

Detailed reference viewed: 67 (18 ULiège)
Full Text
See detailSiting Renewable Power Generation Assets with Combinatorial Optimization
Berger, Mathias ULiege; Radu, David-Constantin ULiege; Dubois, Antoine ULiege et al

E-print/Working paper (2020)

This paper studies the problem of siting renewable power generation assets using large amounts of climatological data. The problem is cast as a combinatorial optimisation problem seeking to maximise ... [more ▼]

This paper studies the problem of siting renewable power generation assets using large amounts of climatological data. The problem is cast as a combinatorial optimisation problem seeking to maximise spatiotemporal complementarity between sites while accounting for electrical load level and chronology. Model properties are closely analysed and a formal connection with the problem of maximising a submodular set function subject to a cardinality constraint is established. A custom solution method combining relaxation-based and local search algorithms is also proposed and benchmarked against state-of-the art methods using a realistic instance comprising tens of thousands of variables inspired by the problem of siting onshore wind power plants in Europe. Results show that for the present application, the proposed solution method is competitive with state-of-the-art methods both in terms of computing time and solution quality, as it reaches objective values at least as good as the proposed benchmarks on most instances studied and clearly outperforms them on a number of occasions. In addition, results highlight the importance of combining a relaxation-based method with a local search algorithm to produce high-quality solutions for this application. [less ▲]

Detailed reference viewed: 211 (40 ULiège)
Full Text
See detailProfiling novel high-conductivity 2D semiconductors
Sohier, Thibault ULiege; Gibertini, Marco; Marzari, Nicola

E-print/Working paper (2020)

When complex mechanisms are involved, pinpointing high-performance materials within large databases is a major challenge in materials discovery. We focus here on phonon-limited conductivities, and study ... [more ▼]

When complex mechanisms are involved, pinpointing high-performance materials within large databases is a major challenge in materials discovery. We focus here on phonon-limited conductivities, and study 2D semiconductors doped by field effects. Using state-of-the-art density-functional perturbation theory and Boltzmann transport equation, we discuss 11 monolayers with outstanding transport properties. These materials are selected from a computational database of exfoliable materials providing monolayers that are dynamically stable and that do not have more than 6 atoms per unit cell. We first analyze electron-phonon scattering in two well-known systems: electron-doped InSe and hole-doped phosphorene. Both are single-valley systems with weak electron-phonon interactions, but they represent two distinct pathways to fast transport: a steep and deep isotropic valley for the former and strongly anisotropic electron-phonon physics for the latter. We identify similar features in the database and compute the conductivities of the relevant monolayers. This process yields several high-conductivity materials, some of them only very recently emerging in the literature (GaSe, Bi$_2$SeTe$_2$, Bi$_2$Se$_3$, Sb$_2$SeTe$_2$), others never discussed in this context (AlLiTe$_2$, BiClTe, ClGaTe, AuI). Comparing these 11 monolayers in detail, we discuss how the strength and angular dependency of the electron-phonon scattering drives key differences in the transport performance of materials despite similar valley structure. We also discuss the high conductivity of hole-doped WSe$_2$, and how this case study shows the limitations of a selection process that would be based on band properties alone. [less ▲]

Detailed reference viewed: 86 (9 ULiège)
Full Text
See detailCombining optimization and simulation for microgrid sizing
Dakir, Selmane ULiege; Cornélusse, Bertrand ULiege

E-print/Working paper (2020)

The sizing of a microgrid is a crucial process to ensure safe, efficient and economical operations. It must consider a variety of technologies and the whole life of the project. Hence degradation and ... [more ▼]

The sizing of a microgrid is a crucial process to ensure safe, efficient and economical operations. It must consider a variety of technologies and the whole life of the project. Hence degradation and reinvestment must be accounted for. However, the control algorithm also influences the sizing result, especially if the microgrid is grid-tied, which offers several revenue streams and presents additional constraints such as time-varying connection limits. All this leads to a sizing problem that is large and non-convex. This paper presents a flexible approach to approximate the solution of this problem. The latter is decomposed in three nested sub-problems: the control and simulation of a microgrid for a given configuration and initial state; the evaluation of a configuration and control policy on a sample of representative days; the optimization of the configuration. Case studies highlight the importance of accounting for the control policy and device evolution along their lifetime. [less ▲]

Detailed reference viewed: 172 (33 ULiège)
Full Text
See detailYAAI: Yet another age inequality
Beckers, Jean-Marie ULiege

E-print/Working paper (2020)

Detailed reference viewed: 47 (1 ULiège)
Full Text
See detailMotivation in schizophrenia: a theory-driven approach using time-series network analysis
Thonon, Bénédicte ULiege; Contreras, Alba; Laroi, Frank ULiege

E-print/Working paper (2020)

Motivational negative symptoms are an important obstacle to the daily functioning of individuals with schizophrenia. A better understanding of associated processes would help to identify targets for ... [more ▼]

Motivational negative symptoms are an important obstacle to the daily functioning of individuals with schizophrenia. A better understanding of associated processes would help to identify targets for interventions. We redefined a theoretical model of motivation in schizophrenia combining cognitive, behavioural and emotional/hedonic processes. Further, we used Experience Sampling Method (ESM) and network analyses to provide a clearer understanding of potential causal factors that may influence the daily course of motivation. Using a 14-day paradigm ESM in 7 participants with schizophrenia spectrum disorders, we examined the interplay between the processes derived from the proposed model. We estimated both contemporaneous and temporal networks using multilevel vector autoregressive analyses for time-series. The contemporaneous network showed that motivation was central and strongly related to levels of energy and (self-)confidence. The temporal network showed that savouring processes (i.e. reminiscence and projection into the future) were the most influential and had an impact on later motivation, mood, effort, energy, (self-)confidence, and dysfunctional beliefs. These findings provide evidence in favour of the motivational model presented in this study, shedding new light on the understanding of motivation in schizophrenia and specifically identifying energy levels, confidence, and savouring skills as likely beneficial targets for interventions. [less ▲]

Detailed reference viewed: 108 (7 ULiège)
Full Text
See detailExpansions in Cantor real bases
Charlier, Emilie ULiege; Cisternino, Célia ULiege

E-print/Working paper (2020)

We introduce and study series expansions of real numbers with an arbitrary Cantor real base. In doing so, we generalize both representations of real numbers in real bases and through Cantor series. We ... [more ▼]

We introduce and study series expansions of real numbers with an arbitrary Cantor real base. In doing so, we generalize both representations of real numbers in real bases and through Cantor series. We show fundamental properties of these new representations, each of which extends existing results on representations in a real base. In particular, we prove a generalization of Parry's theorem characterizing sequences of nonnegative integers that are the greedy representations of some real number in the interval [0,1). We pay special attention to periodic Cantor real bases, which we call alternate bases. In this case, we show that the associated shift is sofic if and only if all quasi-greedy shifted expansions of 1 are ultimately periodic. [less ▲]

Detailed reference viewed: 36 (8 ULiège)
Full Text
See detailPrivate Equity and Employee Welfare
Lambert, Marie ULiege; Moreno Miranda, Nicolas ULiege; Phalippou, Ludovic

E-print/Working paper (2020)

The analysis of one million written reviews and ve million quantitative ratings shows that employees dislike ownership changes, and more so when their company goes under private equity ownership. With ... [more ▼]

The analysis of one million written reviews and ve million quantitative ratings shows that employees dislike ownership changes, and more so when their company goes under private equity ownership. With private equity, there are less complaints about ine ciencies and more complaints about management attitude towards other employees, which exacerbates a pre-existing welfare gap with management. While some generalist sponsors are associated with rating improvements, several sponsors specializing in Tech-Buyouts have negative ratings across their companies; showing heterogeneity of management practices across sponsors. [less ▲]

Detailed reference viewed: 126 (22 ULiège)
Full Text
See detailCompletion/Drop out and Time to Degree in the PhD track: A Conceptual Literature Review
Aerts, Stéphanie ULiege; Haesbroeck, Gentiane ULiege; Klenkenberg, Sophie ULiege

E-print/Working paper (2020)

Understanding the attrition among PhD candidates and modelling the mean or median time to degree according to certain factors have been at the center of the research interest in higher education for a ... [more ▼]

Understanding the attrition among PhD candidates and modelling the mean or median time to degree according to certain factors have been at the center of the research interest in higher education for a long time. This paper presents a conceptual literature review divided into two parts. First, the multitude of factors used to explain the doctoral outcome is presented and results concerning their impact are summarized. We also propose explanations for potentially controversial findings and advice on the proper use of these factors. Then, an overview of the most common statistical techniques employed is displayed. The authors argue that some techniques are more adapted than others to deal with such data and the issues of interest and they give recommendations about the most appropriate techniques. They also highlight some of the key points that are essential to consider in order to conduct an adequate statistical analysis when dealing with PhD data. An overall conclusion is that there is much variability in the factors and their definitions, the same comment holding for the techniques. This explains why studies end up with different (sometimes controversial) results. [less ▲]

Detailed reference viewed: 99 (24 ULiège)
Full Text
Peer Reviewed
See detailTranscending the transcendental: Towards a constructive critical sociology
Frère, Bruno ULiege; Jaster, Dan

E-print/Working paper (2020)

This article calls for a rethinking of critical sociology. The popular Bourdieusian paradigm effectively highlighted how domination persists, but its negative foundation removes the voices of actors by ... [more ▼]

This article calls for a rethinking of critical sociology. The popular Bourdieusian paradigm effectively highlighted how domination persists, but its negative foundation removes the voices of actors by privileging sociological knowledge as capable of identifying transcendental categories of thought. Latourian critical theory arose in opposition to this privileging, but underplayed the roles of domination and power dynamics, and thus critique. We propose a perspective that evades the transcendental perspective which relies on pure negation but allows critique; a more positive critical sociology. This alternative perspective is founded on processualist, phenomenological, pragmatic, and utopian perspectives, which levels the distinction between social scientists and social actors. Focusing on process, not privileged knowledge of transcendental truths, emphasizes actors’ own critical capacities: critical scholars do not dominate, but help actors build better worlds based on their own perspectives and pasts. Thus, critical sociology does not negate actors, reducing them to unconscious reifiers, but recognizes that people utilize their pasts to challenge power structures and create better futures based on their imaginations.   [less ▲]

Detailed reference viewed: 154 (8 ULiège)
Full Text
See detailIdentifier des Activités Génératrices de Revenus
Vermeulen, Cédric ULiege

E-print/Working paper (2020)

Detailed reference viewed: 32 (4 ULiège)
Full Text
See detailAgency costs of dry powder
Lambert, Marie ULiege; Scivoletto, Alexandre ULiege; Tykvova, Tereza

E-print/Working paper (2020)

About $2tn has been raised but have not yet been invested in private equity funds. This amount of non-invested capital or “dry powder” has raised numerous concerns regarding potential pressure to invest ... [more ▼]

About $2tn has been raised but have not yet been invested in private equity funds. This amount of non-invested capital or “dry powder” has raised numerous concerns regarding potential pressure to invest in low-quality companies for these funds with adverse consequence on fund performance. We model the total fee revenue (management fee and carried interest) collected by a private equity sponsor as a function of committed capital, net invested capital as well as the risk and return of the fund investments. We show that higher deal expected returns and higher management fees as associated with a stronger pressure on dry powder. On the other hand, an increase in the carried interest or the existence of a valuable option to delay investment to benefit from better opportunities reduce this pressure. We run an empirical analysis using 12,779 leveraged buyout deals from the US over the period 1980 – 2019 that supports our predictions from the theoretical model. Moreover, dry powder pressure is associated with investment distortions. It leads to inflated deal prices, lower returns and lower leverage. [less ▲]

Detailed reference viewed: 76 (5 ULiège)
Full Text
See detailThe Seasons of the True Size Anomaly
Fays, Boris ULiege; Hübner, Georges ULiege; Lambert, Marie ULiege

E-print/Working paper (2020)

Detailed reference viewed: 33 (2 ULiège)
Full Text
Peer Reviewed
See detailReappraisal of the Concept of New Brutalism in Contemporary Architecture
Van Rooyen, Xavier ULiege

E-print/Working paper (2020)

In the 1960s, the New Brualism movement witnessed two opposing conceptions that can give rise to "Smithsons’ Brutalism and Banham’s Brutalism" The first one had the ambition to propose an "art of ... [more ▼]

In the 1960s, the New Brualism movement witnessed two opposing conceptions that can give rise to "Smithsons’ Brutalism and Banham’s Brutalism" The first one had the ambition to propose an "art of inhabitation" . This art of inhabitation also involves the use of "as found" materials. For the Smithsons, "as found was a new seeing of the ordinary, an openness as to how prosaic "things" could re-energise our inventive activity” . For the Smithsons, "Until now, brutalism has only been the subject of stylistic discussion, whereas its essence is ethical." In 1966, Reyner Banham published the first historiography associated with the New Brutalism movement. In this book, entitled The New Brutalism: Ethic or Aesthetic? . Banham attempts to list and illustrate a series of projects that he considers representative of a "brutalist style". The English critic focuses instead on the aesthetic stakes of New Brutalism. Nevertheless, both visions put forward the use of as found materials. In the field of contemporary architecture, we can perceive the aesthetic/ethical duality in the theories of the reuse of "as found" materials. Our article aims to characterize the two approaches of New Brutalism and to understand how these conceptions are reappraised in the field of contemporary architecture. More precisely, we will investigate the question of the reuse of materials through case studies, which, in a period of "climatic urgency", decreed by the European Parliament in particular, re-actualizes the ethical ambition of New Brutalism. [less ▲]

Detailed reference viewed: 31 (5 ULiège)
Full Text
See detailOn the origin of jotunite
Duchesne, Jean-Clair ULiege

E-print/Working paper (2019)

Detailed reference viewed: 47 (8 ULiège)
Full Text
Peer Reviewed
See detailEmissions de CO2 liées à la navigation aérienne à Liège Airport
Ozer, Pierre ULiege

E-print/Working paper (2019)

Detailed reference viewed: 1893 (44 ULiège)
Full Text
Peer Reviewed
See detailPaper Formats of the Mamluk Period: The Contribution of Mamluk Chancery Paper
Bauden, Frédéric ULiege

E-print/Working paper (2019)

Detailed reference viewed: 203 (9 ULiège)
Full Text
See detailColumn generation algorithms for the wafer-to-wafer integration problem
Dokka, Trivikram; Crama, Yves ULiege; Duvillié, Guillerme et al

E-print/Working paper (2019)

We consider the wafer-to-wafer integration problem that arises in the manufacturing of integrated circuits. We propose an exact, state-of-the-art branch-and-price optimization algorithm for this problem ... [more ▼]

We consider the wafer-to-wafer integration problem that arises in the manufacturing of integrated circuits. We propose an exact, state-of-the-art branch-and-price optimization algorithm for this problem, and we derive a price-and-branch heuristic from this algorithm. We have implemented these two algorithms, as well as a simple sequential heuristic algorithms, and we have conducted extensive experiments to test their performance. The results allow us to establish the range of the size of the instances that can be solved to optimality by our branch-and-price algorithm. We also identify ranges of the different instance parameters for which the two heuristics perform relatively well. [less ▲]

Detailed reference viewed: 55 (2 ULiège)
Full Text
Peer Reviewed
See detailPaper documents from Iṣṭabl ʿAntar: Assessment of the findings and data analysis
Bauden, Frédéric ULiege

E-print/Working paper (2019)

Detailed reference viewed: 101 (6 ULiège)
Full Text
Peer Reviewed
See detailPilgrimage Certificates from the Mamluk Period: New Data
Bauden, Frédéric ULiege

E-print/Working paper (2019)

Detailed reference viewed: 115 (13 ULiège)
Full Text
See detailReconstruction of low-voltage networks with limited observability
Marulli, Daniele ULiege; Mathieu, Sébastien ULiege; Sutera, Antonio ULiege et al

E-print/Working paper (2019)

This work addresses the problem of reconstructing an electrical model for low voltage networks when no information about topology and line parameters is available. Obtaining an accurate electrical model ... [more ▼]

This work addresses the problem of reconstructing an electrical model for low voltage networks when no information about topology and line parameters is available. Obtaining an accurate electrical model for such networks is essential to establish efficient and ad hoc management strategies. The identification process is carried out analysing voltage and current time-series measurements provided by meters installed at various locations, assuming that only a subset of the nodes can be metered. The proposed method involves an iterative algorithm that provides an estimation of the topology and branch impedances while detecting the location of unmetered nodes, one node per iteration. Simulations performed on a test network shows that the algorithm produces accurate estimation of topology and line impedances when unmetered nodes are located reasonably far from each other. [less ▲]

Detailed reference viewed: 291 (32 ULiège)
Full Text
See detailTroeltsch et les religions : le luthérianisme, le calvinisme et le catholicisme
Kuty, Olgierd ULiege

E-print/Working paper (2019)

Detailed reference viewed: 36 (4 ULiège)
Full Text
See detailLes professions et la Révolution organisationnelle (du XVIème au XVIIIème siècle)
Kuty, Olgierd ULiege

E-print/Working paper (2019)

Detailed reference viewed: 35 (0 ULiège)
Full Text
See detailLe concept de « Manières » dans l’œuvre de Montesquieu
Kuty, Olgierd ULiege

E-print/Working paper (2019)

Detailed reference viewed: 31 (3 ULiège)
Full Text
See detailMontesquieu et sa théorie de la structure sociale
Kuty, Olgierd ULiege

E-print/Working paper (2019)

Detailed reference viewed: 26 (0 ULiège)
Full Text
Peer Reviewed
See detailData-driven Parameterized Policies for Microgrid Control
Boukas, Ioannis ULiege; El Mekki, Sélim ULiege; Cornélusse, Bertrand ULiege

E-print/Working paper (2019)

If we account for data uncertainty, centralized microgrid control can be decomposed in four tasks: estimating the parameters of the microgrid devices, forecasting the consumption and the renewable ... [more ▼]

If we account for data uncertainty, centralized microgrid control can be decomposed in four tasks: estimating the parameters of the microgrid devices, forecasting the consumption and the renewable production, operational planning to anticipate weather effects and human activities, and real-time control to adapt planned decision to the reality of the moment. As the devices of a microgrid deteriorate over their lifetime and microgrids are by definition small systems, it is of paramount importance to automate the meta-parameterization of these stages to maximize the microgrid efficiency and decrease its maintenance costs. This paper studies how reinforcement learning can be used to address this problem. As reinforcement learning makes use of microgrid operation data (or of simulated data before the microgrid is actually operated) to learn an operation policy, it inherently merges the four stages above, and can in theory adapt to some types of changes without having to perform manual tuning. [less ▲]

Detailed reference viewed: 132 (14 ULiège)
Full Text
See detailDoes training boost the job finding rate of the unemployed ? Timing-of-events based evidence from Belgium
Fonder, Muriel; Lejeune, Bernard ULiege; Tarantchenko, Ekaterina

E-print/Working paper (2019)

This paper evaluates the effectiveness of the training programs offered to the unemployed in Wallonia, the French-speaking part of Belgium. More precisely, we are interested in the two following questions ... [more ▼]

This paper evaluates the effectiveness of the training programs offered to the unemployed in Wallonia, the French-speaking part of Belgium. More precisely, we are interested in the two following questions : (a) does training increase the job finding rate of the unemployed after the completion of their training ? (b) if so, is this increase big enough to compensate the so-called lock-in effect of their training ? To answer these questions, we rely on the Abbring and van den Berg (2003) timing-of-events approach and a very large administrative dataset. We find that training has an overall strong and persistent effect on the job finding rate of the unemployed after the completion of their training, but that this effect is heterogeneous, varying according to the characteristics of training and trainees. Further, we find that this effect on the job finding rate is globally large enough to compensate the lock-in effect of the training, but again with significant heterogeneity. [less ▲]

Detailed reference viewed: 54 (5 ULiège)
Full Text
See detailRecourse in Kidney Exchange Programs
Smeulders, Bart ULiege; Bartier, Valentin; Crama, Yves ULiege et al

E-print/Working paper (2019)

The problem to decide which patient-donor pairs in a kidney exchange program should undergo a crossmatch test is modelled as a two-stage stochastic optimization problem. We give an integer programming ... [more ▼]

The problem to decide which patient-donor pairs in a kidney exchange program should undergo a crossmatch test is modelled as a two-stage stochastic optimization problem. We give an integer programming formulation of this so-called selection problem, and describe a solution method based on Benders decomposition. We extensively test various solution methods, and observe that the solutions, when compared to solutions found by recourse models, lead to an improvement in the expected number of transplants. We also investigate the computational efficiency of our approach as a function of different parameters, such as maximum cycle length and the presence of altruistic donors. [less ▲]

Detailed reference viewed: 54 (4 ULiège)
Full Text
See detailInterest rate differentials and the dynamic asymmetry of exchange rates
Hambuckers, Julien ULiege; Ulm, Maren

E-print/Working paper (2019)

In this paper, we revisit the predictive content of interest rates for daily exchange rate returns, taking into account dependencies of higher orders. In particular, we allow for time-varying asymmetries ... [more ▼]

In this paper, we revisit the predictive content of interest rates for daily exchange rate returns, taking into account dependencies of higher orders. In particular, we allow for time-varying asymmetries in the distribution of exchange rates. Then, we study the USD/EUR currency pair over the period 1999-2019. We find a dynamic asymmetry component to be significant and driven by interest rate differentials, but also by general uncertainty and past unexpected shocks. In line with recent currency crash theories, our study suggests that the high yield currency is more likely to appreciate, but is exposed to a higher likelihood of currency crashes. To assess the economic significance of our results, we introduce a directional forecasting approach derived from our model. We show that a trading rule based on these forecasts provides better in-sample and out-of-sample economic performance compared to benchmark models. [less ▲]

Detailed reference viewed: 57 (7 ULiège)
Full Text
Peer Reviewed
See detailLa longue et fascinante épopée de la vaccination
Geenen, Vincent ULiege

E-print/Working paper (2019)

Vaccination is still today the greatest victory of medicine against most of infectious diseases, and this triumph was acquired only after a long history that started hundred of years ago. Nevertheless ... [more ▼]

Vaccination is still today the greatest victory of medicine against most of infectious diseases, and this triumph was acquired only after a long history that started hundred of years ago. Nevertheless, irrational anti-vaccination movements emerged worldwide during recent years and are now one of the ten major threats against public healthcare according to a recent report of the World Health Organization (WHO). More than ever, it is essential to inform with honesty and integrity our citizens about the safety and efficiency of current available vaccines. [less ▲]

Detailed reference viewed: 98 (14 ULiège)
Full Text
See detailData requirements for computational modelling at the network level
Dewals, Benjamin ULiege; Erpicum, Sébastien ULiege; Pirotton, Michel ULiege et al

E-print/Working paper (2019)

Detailed reference viewed: 34 (9 ULiège)
Full Text
See detailAuthentic ecology as an advanced stage of technological civilization
de Salle, Corentin; Ernst, Damien ULiege

E-print/Working paper (2019)

Detailed reference viewed: 32 (4 ULiège)
Full Text
See detailTemplates for the k-binomial complexity of the Tribonacci word
Lejeune, Marie ULiege; Rigo, Michel ULiege; Rosenfeld, Matthieu ULiege

E-print/Working paper (2019)

Consider the k-binomial equivalence: two finite words are equivalent if they share the same subwords of length at most k with the same multiplicities. With this relation, the k-binomial complexity of an ... [more ▼]

Consider the k-binomial equivalence: two finite words are equivalent if they share the same subwords of length at most k with the same multiplicities. With this relation, the k-binomial complexity of an infinite word x maps the integer n to the number of pairwise non-equivalent factors of length n occurring in x. In this paper based on the notion of template introduced by Currie et al., we show that, for all k > 1, the k-binomial complexity of the Tribonacci word coincides with its usual factor complexity p(n)=2n+1. A similar result was already known for Sturmian words but the proof relies on completely different techniques that seemingly could not be applied for Tribonacci. [less ▲]

Detailed reference viewed: 79 (17 ULiège)
Full Text
See detailVoiture électrique : 697.612 km pour devenir verte ! Vrai ou faux ?
Ernst, Damien ULiege

E-print/Working paper (2019)

Detailed reference viewed: 191 (8 ULiège)
Full Text
See detailElectric car: 697,612 km to become green! True or false?
Ernst, Damien ULiege

E-print/Working paper (2019)

Detailed reference viewed: 169 (5 ULiège)
Full Text
See detailDebating the Measure: Steve Reich’s Sociological Imagination.
Orianne, Jean-François ULiege

E-print/Working paper (2019)

This article intends to identify the contributions of Steve Reich's music to sociology. His music presents three main characteristics: it is made out of empirical material collected on the field; it is a ... [more ▼]

This article intends to identify the contributions of Steve Reich's music to sociology. His music presents three main characteristics: it is made out of empirical material collected on the field; it is a theory of processes; it is a political and cultural act. Steve Reich's music affects sociology on these three points: it reminds the social scientist of the nature of his craft and his commitment to the social world, questions his methods and practices; it even sheds light on some of his familiar concepts (in particular that of ‘process’). The author proposes to extract from Steve Reich’s compositional work some elements that could prove useful for sociology as a profession. [less ▲]

Detailed reference viewed: 102 (3 ULiège)
Full Text
See detailLevallois et Gravettien
Otte, Marcel ULiege; Noiret, Pierre ULiege

E-print/Working paper (2019)

Par opposition à ceux de l’Aurignacien, les ensembles lithiques gravettiens procèdent selon une méthode rappelant le Levallois quant à la préparation des supports. Mais les variations observables au sein ... [more ▼]

Par opposition à ceux de l’Aurignacien, les ensembles lithiques gravettiens procèdent selon une méthode rappelant le Levallois quant à la préparation des supports. Mais les variations observables au sein du Gravettien touchent autant les processus de symbolisation dans l’art et les sépultures. Elles affectent différents substrats eurasiatiques, plutôt septentrionaux, comme mis en réserve dès les Néandertaliens. [less ▲]

Detailed reference viewed: 126 (16 ULiège)
Full Text
See detailRecourse in Kidney Exchange Programs
Bartier, Valentin; Smeulders, Bart ULiege; Crama, Yves ULiege et al

E-print/Working paper (2019)

The problem to decide which patient-donor pairs in a kidney exchange program should undergo a cross-match test is modelled as a two-stage stochastic optimization problem. We give an integer programming ... [more ▼]

The problem to decide which patient-donor pairs in a kidney exchange program should undergo a cross-match test is modelled as a two-stage stochastic optimization problem. We give an integer programming formulation of this so-called selection problem, and describe a solution method based on Benders decomposition. We extensively test various solution methods, and observe that the solutions, when compared to solutions found by recourse models, lead to an improvement in the expected number of transplants. We also investigate the computational efficiency of our approach as a function of different parameters, such as maximum cycle length and the presence of altruists. [less ▲]

Detailed reference viewed: 63 (13 ULiège)
Full Text
See detailGuide d'utilisation de Zotero: Fonctionnalités de base de l'outil de gestion bibliographique
Dony, Christophe ULiege

E-print/Working paper (2019)

Detailed reference viewed: 1584 (503 ULiège)
Full Text
See detailMinimal automaton for multiplying and translating the Thue-Morse set
Charlier, Emilie ULiege; Cisternino, Célia ULiege; Massuir, Adeline ULiege

E-print/Working paper (2019)

The Thue-Morse set T is the set of those non-negative integers whose binary expansions have an even number of 1. The name of this set comes from the fact that its characteristic sequence is given by the ... [more ▼]

The Thue-Morse set T is the set of those non-negative integers whose binary expansions have an even number of 1. The name of this set comes from the fact that its characteristic sequence is given by the famous Thue-Morse word abbabaabbaababba..., which is the fixed point starting with a of the word morphism a -> ab; b -> ba. The numbers in T are commonly called the evil numbers. We obtain an exact formula for the state complexity of the set mT + r (i.e. the number of states of its minimal automaton) with respect to any base b which is a power of 2. Our proof is constructive and we are able to explicitly provide the minimal automaton of the language of all 2^p-expansions of the set of integers mT +r for any positive integers p and m and any remainder r between 0 and m-1. The proposed method is general for any b-recognizable set of integers. As an application, we obtain a decision procedure running in quadratic time for the problem of deciding whether a given 2^p-recognizable set is equal to a set of the form mT + r. [less ▲]

Detailed reference viewed: 41 (7 ULiège)
Full Text
See detailOperational risk, uncertainty, and the economy: a smooth transition extreme value approach
Hambuckers, Julien ULiege; Kneib, Thomas

E-print/Working paper (2019)

We study the link between the distribution of extreme operational losses and the economic context, a fundamental task to compute adequate risk measures over time. In particular, we allow for time-varying ... [more ▼]

We study the link between the distribution of extreme operational losses and the economic context, a fundamental task to compute adequate risk measures over time. In particular, we allow for time-varying dependencies due to structural changes, thanks to a newly-introduced smooth transition Generalized Pareto (GP) regression model. In this model, the parameters of the GP distribution are related to explanatory variables through regression functions, which depend themselves on a predictor of structural changes. Relying on this model, we study the dependence of the monthly loss severity distribution at UniCredit, over the period 2005-2014. As indicator of structural changes, we use the VIX, accounting for the general uncertainty on financial markets. We show that both the goodness-of- fit far in the tail and Value-at-Risk estimates of the total loss distribution obtained from such models are superior to a set of alternatives. We also show that in periods of high uncertainty, conditions favorable to a lax monetary policy are synonym of an increased likelihood of extreme losses. Finally, we discover evidence of a self-inhibition mechanism, where a high number of losses in a recent past are indicative of less extreme losses in the future, probably due to improved monitoring. [less ▲]

Detailed reference viewed: 50 (2 ULiège)
Full Text
See detailTowards an extended indexical externalism. Looking for empirical data
De Brabanter, Philippe; Leclercq, Bruno ULiege

E-print/Working paper (2019)

Detailed reference viewed: 36 (1 ULiège)
Full Text
See detailSemantic externalism(s) and semantic deference
De Brabanter, Philippe; Leclercq, Bruno ULiege

E-print/Working paper (2019)

We sketch several variants of so-called “semantic externalism”, which we take to be prototypically embodied by Wittgenstein, Kripke and Burge respectively. Then, drawing inspiration from Putnam, we show ... [more ▼]

We sketch several variants of so-called “semantic externalism”, which we take to be prototypically embodied by Wittgenstein, Kripke and Burge respectively. Then, drawing inspiration from Putnam, we show how aspects of these different kinds of semantic externalism can be articulated with each other in the case of natural kind terms, and we suggest that this analysis could be extended to a larger set of words. When that is done, we turn to the core part of the paper, which consists in a thorough discussion of the forms of “semantic deference” that can plausibly be associated with each brand of externalism. We suggest that the debates over the kinds of semantic externalism characteristic of different kinds of words can be clarified by investigating the kind of semantic deference they call for. [less ▲]

Detailed reference viewed: 71 (3 ULiège)
Full Text
See detailThe golden mountain, the man and the great big elvish warrior. Kripkean and Meinongian readings of definite descriptions in fiction
Leclercq, Bruno ULiege

E-print/Working paper (2019)

The neat distinction between objects and concepts which prevails in standard extensional logic seems to be challenged by inexistent objects. Yet modal logics and Meinongian logics offer two very different ... [more ▼]

The neat distinction between objects and concepts which prevails in standard extensional logic seems to be challenged by inexistent objects. Yet modal logics and Meinongian logics offer two very different non-extensional ways of dealing with such objects. While the former somehow stick to the object-concept distinction, the latter overcome it in such a way that objects come to get most of the main features which standardly characterise concepts. Now, just like non-fictional discourse requires distinguishing between a de re and a de dicto reading of some linguistic expressions, (naïve reading of) fiction requires distinguishing between a de altero mundo and a de dicto reading of expressions. And this pleads for the preservation of the object-concept distinction even for fiction. This is why modal logics provide a better tool for a general theory of reference that accounts both for fictional and non-fictional discourse even if Meinongian logics give a good account of the logic of intension [less ▲]

Detailed reference viewed: 30 (1 ULiège)
Full Text
See detailSolar Rebound The unintended consequences of subsidies
Boccard, Nicolas; Gautier, Axel ULiege

E-print/Working paper (2019)

Many jurisdictions use net metering to record the power exchange between solar photovoltaic panels and the grid, thus valuing home production at the electricity retail rate. However, if over the billing ... [more ▼]

Many jurisdictions use net metering to record the power exchange between solar photovoltaic panels and the grid, thus valuing home production at the electricity retail rate. However, if over the billing period, production exceeds consumption, the surplus remains freely available for consumption. In Wallonia (Belgium), this system was combined with generous subsidies for solar panels that encouraged households to set-up large installations, possibly exceeding their consumption needs. In this context, we test for a possible rebound effect. Based on a large sample of residential PV installations, we observe that a large proportion of households oversized their installation to benefit from the subsidies and, later ended-up consuming most of their excess production. The effect is econometrically highly significant. There are thus evidence of a strong increase in energy consumption by residential PV owners, that runs counter the original policy design. [less ▲]

Detailed reference viewed: 143 (16 ULiège)
Full Text
See detailResource Complementarity as Criterion for Siting Renewable Energy Generation Assets
Radu, David-Constantin ULiege

E-print/Working paper (2019)

Detailed reference viewed: 129 (29 ULiège)
Full Text
Peer Reviewed
See detailGeneration of Parallel Corpus for Low Resource Language Translation
Trieu, Long Hai; Ittoo, Ashwin ULiege

E-print/Working paper (2019)

Detailed reference viewed: 37 (1 ULiège)
Full Text
Peer Reviewed
See detail“Mapping and Testing Social Enterprise Models Across the World: Evidence from the “International Comparative Social Enterprise Models (ICSEM) Project”,
Defourny, Jacques ULiege; Nyssens, Marthe; Brolis, Olivier ULiege

E-print/Working paper (2018)

The relevance of an international typology of SE models, as proposed by Defourny and Nyssens (2017) is tested through an Hierarchical Cluster Analysis of a database covering 740 social enterprises in 43 ... [more ▼]

The relevance of an international typology of SE models, as proposed by Defourny and Nyssens (2017) is tested through an Hierarchical Cluster Analysis of a database covering 740 social enterprises in 43 countries from all world regions. Three of the four proposed SE models find a strong empirical support: the "Entrepreneurial Nonprofit", the "Social Cooperative" and the "Social Business" models [less ▲]

Detailed reference viewed: 254 (5 ULiège)
Full Text
See detailHenry Clews: Twenty-Eight Years in Wall Street
Choffray, Jean-Marie ULiege

E-print/Working paper (2018)

Word of caution: I am happy to share my summary of one of the best books ever written on how financial markets function and professional investors/speculators behave. Some of the observations and ... [more ▼]

Word of caution: I am happy to share my summary of one of the best books ever written on how financial markets function and professional investors/speculators behave. Some of the observations and inferences made by Henry Clews, more than one hundred years ago, may sometimes appear a bit crude, if not biased – specially to those of us who live on this side of the Atlantic! – but they don’t overshadow his honest desire to observe, understand and share financial markets history as it unfolds. I think that most of his comments and advices are perfectly relevant today in our digitalized investment environment. That’s why, under the influence of some of my past students, I finally decided to share my “personal” summary of this exceptional piece of work. If it leads you to read the 724 pages of the original, I will have done useful work. [less ▲]

Detailed reference viewed: 223 (23 ULiège)
Full Text
See detailProjet JOS. Compte-rendu de l'enquête menée dans les jardins partagés luxembourgeois
Gérard, Marie ULiege

E-print/Working paper (2018)

Les commentateurs concernés par la question des jardins s’accordent aujourd’hui sur un point : après une éclipse qui trouve son point de départ dans les bouleversements que provoque la révolution ... [more ▼]

Les commentateurs concernés par la question des jardins s’accordent aujourd’hui sur un point : après une éclipse qui trouve son point de départ dans les bouleversements que provoque la révolution industrielle, et qui s’aggravent avec l’entreprise de « modernisation » de l’après-guerre (la période dite des « Trente Glorieuses »), un « retour au jardin » s’est amorcé au début des années 1980. Depuis lors, pas un jour sans que la restauration d’un « jardin historique » ne soit programmée, sans qu’un nouveau manuel de jardinage ne soit publié, sans qu’une « fête des plantes » ne soit organisée. On s’en doute : les « jardins partagés », ces jardins « communautaires » qui ont vu le jour dans les villes du vieux continent à la fin des années 1990, participent de ce renouveau. Mais que se joue-t-il à travers ce retour au jardin ? Et en quoi cela concerne-t-il les jardins partagés ? Ce travail, qui rend compte d’une enquête menée au mois de juin 2018 dans les jardins partagés luxembourgeois engagés dans le projet JOS, se confrontera à ces deux questions. [less ▲]

Detailed reference viewed: 32 (4 ULiège)
Full Text
See detailNotes on security of electricity supply, some practical problems in MV/LV networks and legal aspects of building global grid
Glavic, Mevludin ULiege

E-print/Working paper (2018)

This documents presents a note on security of electricity supply and several short notes on some technical problems in MV/LV networks and legal aspects related to building global grid. The only aim of the ... [more ▼]

This documents presents a note on security of electricity supply and several short notes on some technical problems in MV/LV networks and legal aspects related to building global grid. The only aim of the document is to provide potentially useful material for those interested in the problems (particularly those at initial stage of their research). Considered problems include: 1. Security of electricity supply, 2. Approaches for optimal placement of DGs and EV’s charging stations, 3. Approaches for corrective measures (load flexibility and generation curtailment) in LV networks, 4. Approaches to infer LV network model from smart meter data, 5. Approaches for phases balancing in LV networks, 6. Approaches for voltage and thermal overload control in active distribution networks, and 7. Legal aspects related to building Global Grid. [less ▲]

Detailed reference viewed: 44 (5 ULiège)
Full Text
See detailTerminologia multilingue in medicina di famiglia Versione 2.5 italiana
Jamoulle, Marc ULiege; Demurtas, Jacopo; Pesolillo, Gabriella et al

E-print/Working paper (2018)

Detailed reference viewed: 33 (1 ULiège)
Full Text
See detailDoes Coriolis force influence the flow in shallow reservoirs?
Dewals, Benjamin ULiege

E-print/Working paper (2018)

Detailed reference viewed: 19 (0 ULiège)
Full Text
See detailGuidelines related to the use of an existing cavity (mine/quarry) as reservoir of a pumped storage hydroelectric facility
Cerfontaine, Benjamin ULiege; Ronchi, Benedicta; Archambeau, Pierre ULiege et al

E-print/Working paper (2018)

Underground mines/quarries or open pits are manmade earthworks resulting from previous extraction of natural resources. They were mostly abandoned after resources depletion but underground or surface ... [more ▼]

Underground mines/quarries or open pits are manmade earthworks resulting from previous extraction of natural resources. They were mostly abandoned after resources depletion but underground or surface excavations remain. Pumped Storage Hydroelectricity (PSH) is one of the only efficient solutions for large scale energy storage. During peaks of energy production, water is pumped from a lower reservoir to an upper reservoir. On the other hand when demand peaks, energy is generated when water is transferred to the lower reservoir. The objective of this work is to study the recovering of abandoned excavation volumes as lower reservoirs for pumped storage hydroelectricity. Underground Pumped Storage Hydroelectricity (UPSH) is a particular case where at least one of the reservoir lies below the surface. Compare to classical PSH plants, using an existing cavity as a reservoir raises three main additional problems: 1) What are the water movements and thus discharge availability at the pump/turbine location depending on the reservoir (complex) geometry? 2) What are the exchanges between the reservoir (usually not watertight) and the surrounding medium? 3) How can the reservoir sides resist to cyclic loading imposed by the plant operation? In the following, some simplified criteria and issues are provided to carry out feasibility assessments of such rehabilitation projects, from the existing reservoir point of view. These criteria do no replace a detailed and complete study but draws the attention on problems specific to PSH using existing cavities as reservoir. They do not concern problems existing for every PSH project, such as location of electricity transport lines, availability of water… [less ▲]

Detailed reference viewed: 224 (13 ULiège)
Full Text
See detailUn mathématicien contemporain emblématique: Sir William Timothy Gowers
Bair, Jacques ULiege

E-print/Working paper (2018)

William Timothy (ou simplement Tim) Gowers est un des meilleurs mathématiciens de cette époque. Au-delà des résultats mathématiques originaux et profonds qu’il a trouvés, il présente (au moins) quatre ... [more ▼]

William Timothy (ou simplement Tim) Gowers est un des meilleurs mathématiciens de cette époque. Au-delà des résultats mathématiques originaux et profonds qu’il a trouvés, il présente (au moins) quatre particularités épistémologiques qui n’étaient pas encore d’actualité dans le passé et semblaient dès lors peu préoccuper les grands mathématiciens des siècles précédents, mais qui nous paraissent prises en compte par certains savants de la présente époque travaillant dans la direction tracée par T. Gowers. 1) Dans ses recherches mathématiques, il rapproche des théories mathématiques qui a priori semblent éloignées les unes des autres. 2) Il cherche à mieux faire comprendre les mathématiques à tous niveaux et contribue à la publication d’ouvrages de (haute) vulgarisation. 3) Il milite pour une science ouverte, en « open access ». 4) Il promeut une résolution collaborative de problèmes mathématiques ardus. [less ▲]

Detailed reference viewed: 52 (2 ULiège)
Full Text
See detailAphorismes mathématiques de J. Ellenberg
Bair, Jacques ULiege

E-print/Working paper (2018)

J. S. Ellenberg est un des meilleurs mathématiciens de notre temps. Il a écrit un livre remarquable intitulé en anglais "How not to be wrong", traduit en français sous le titre "L'art de ne pas dire n ... [more ▼]

J. S. Ellenberg est un des meilleurs mathématiciens de notre temps. Il a écrit un livre remarquable intitulé en anglais "How not to be wrong", traduit en français sous le titre "L'art de ne pas dire n'importe quoi". D'après l'auteur, " il voulait expliquer aux gens, en détail, combien les maths sont fantastiques". Nous reprenons dans cette note quelques extraits qui nous semblent contenir des idées profondes et pertinentes à propos des mathématiques, de leur enseignement et de leur heuristique (c'est-à-dire la façon de les trouver); nous les appelons des "aphorismes mathématiques". [less ▲]

Detailed reference viewed: 21 (0 ULiège)