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See detailPB 8783: the first sdO star suitable for asteroseismic modeling?
Van Grootel, Valérie ULiege; Randall, Suzanna K.; Latour, Marilyn et al

E-print/Working paper (in press)

Pulsating hot B subdwarfs (sdB) have become one of the showcases of asteroseismology. Thanks to the combination of rich observed pulsation spectra and state-of-the-art modeling tools it is possible to ... [more ▼]

Pulsating hot B subdwarfs (sdB) have become one of the showcases of asteroseismology. Thanks to the combination of rich observed pulsation spectra and state-of-the-art modeling tools it is possible to tightly constrain fundamental parameters such as the stellar mass for these compact, evolved objects in the core He-burning phase of evolution. In comparison, the exploitation of sdO pulsators - hotter stars thought to be in a more advanced evolutionary stage - is still in its infancy. While a small number have been identified in Globular Clusters (GCs), they are extremely rare among the field population. It was recently suggested that PB8783, one of the very first sdB pulsators discovered in 1997, may in fact be an unrecognized hot sdO star with very similar properties to the GC sdO pulsators. Here, we present new very high-quality spectroscopy as well as an asteroseismic analysis of this star with the aim of solving the mystery of its nature. [less ▲]

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See detailInformal fatigue-related risk management in the emergency department: a trade-off between doing well and feeling well?
Berastegui, Pierre ULiege; Jaspar, Mathieu ULiege; Ghuysen, Alexandre ULiege et al

E-print/Working paper (in press)

The effect of shift work on health and safety has long been a concern of public authorities, and increasingly stringent directives have been issued over the past decades. However, there are evidences that ... [more ▼]

The effect of shift work on health and safety has long been a concern of public authorities, and increasingly stringent directives have been issued over the past decades. However, there are evidences that current directives still represent a hazard in some work settings by disturbing the sleep/wake regulation processes. Emergency physicians are known to be particularly vulnerable to sleep deprivation due to inconsistent shift rotation, extended duty periods and overnight calls. However, naturalistic studies have actually failed to systematically demonstrate that sleep deprivation is associated with poorer work performance in emergency physicians. The inconsistency of these results could reside in physicians’ ability to compensate for fatigue-related impairments. Our aim is to identify informal fatigue management strategies used by emergency physicians and to assess the efficiency in terms of fatigue, work performance and associated risks for physician burnout. We conducted a prospective longitudinal study with 28 emergency physicians for a total of 182 shifts. At enrolment, participants answered the Maslach Burnout Inventory and the Fatigue Management Survey. During shifts, we measured fatigue using the Psychomotor Vigilance Task and work performance using an adapted version of the Physician Achievement Review. Our results show that emergency physicians working at this public sector hospital use different types of compensatory strategies to manage fatigue-related risk, and that some of these strategies might result in a trade-off between work performance and occupational burnout. We propose further considerations for the implementation and follow-up of a fatigue risk management system in the emergency department. [less ▲]

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See detailFatigue-related risk perception among emergency physicians working extended shifts.
Berastegui, Pierre ULiege; Jaspar, Mathieu ULiege; Ghuysen, Alexandre ULiege et al

E-print/Working paper (in press)

There is a growing body of studies indicating that extended shift duration has an adverse effect on fatigue, consequently leading to reduced work performance and higher risk of accident. Following modern ... [more ▼]

There is a growing body of studies indicating that extended shift duration has an adverse effect on fatigue, consequently leading to reduced work performance and higher risk of accident. Following modern fatigue risk management systems (FRMS), acceptable performance could be maintained by the mobilization of appropriate mitigation strategies. However, the effective deployment of such strategies assume that workers are able to assess their own level of fatigue-related impairments. In this study, we sought to determine whether emergency physicians’ subjective feelings of sleepiness could provide accurate knowledge of actual fatigue-related impairments while working extended shifts. We conducted a prospective observational study with a within-subjects repeated measures component. We collected sleep logs, sleepiness ratings and reaction times on a Psychomotor Vigilance Task (PVT) at different time points during shifts. Our results show that the PVT is sensitive to sleep loss and fatigue, with a 10% increase in mean reaction time across the shift. Subjective sleepiness, however, showed no significant association with time since awakening and was not a significant predictor of PVT performance. Our results are consistent with experimental studies showing that individuals tend to underestimate fatigue-related impairments when sleep deprived or functioning under adverse circadian phase. The discrepancy between subjective sleepiness and actual fatigue-related impairments may give workers the illusion of being in control and hinder the deployment of mitigation strategies. Further research is needed to determine the relative weight of circadian phase shifting and cumulative sleep deprivation in the decline of self-knowledge in extended shifts. [less ▲]

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See detailFrom justification to phenomenology The moral Imaginary of Solidarity Economy
Frère, Bruno ULiege

E-print/Working paper (2020)

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See detailBeyond Critical Sociology Bourdieu’s Positivism and the Sociology of Critique
Frère, Bruno ULiege; Jaster, Dan

E-print/Working paper (2020)

The aim of this paper is to demonstrate the value of French sociology of critique as a post-Bourdieusian critical sociology. We first show why this sociological paradigm correctly highlights positivistic ... [more ▼]

The aim of this paper is to demonstrate the value of French sociology of critique as a post-Bourdieusian critical sociology. We first show why this sociological paradigm correctly highlights positivistic elements within the Bourdieuian paradigm. Bourdieu’s epistemological barrier between scientists and ordinary actors implies that critical sociologists’ judgments are scientifically true and must be distinguished from the latter’s own understandings of his/her action. This is epistemologically and normatively unsound due to the scientist’s own position within the social milieu. We then propose that critical scholars adopt the sociology of critique approach. This takes actors’ understandings of motivations and actions seriously, minimizing the distance between sociologists’ and actors’ understandings of the social world, better representing people’s social reality. This richer, more reflexive portrait of social life places social scientists in an advantageous position to understand and critically engage with the individuals and communities whom we study. [less ▲]

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See detailThe Role of Power-to-Gas and Carbon Capture Technologies in Cross-Sector Decarbonisation Strategies
Berger, Mathias ULiege; Radu, David-Constantin ULiege; Fonteneau, Raphaël ULiege et al

E-print/Working paper (2019)

This paper proposes an optimisation-based framework to tackle long-term centralised planning problems of multi-sector, integrated energy systems including electricity, hydrogen, natural gas, synthetic ... [more ▼]

This paper proposes an optimisation-based framework to tackle long-term centralised planning problems of multi-sector, integrated energy systems including electricity, hydrogen, natural gas, synthetic methane and carbon dioxide. The model selects and sizes the set of power generation, energy conversion and storage as well as carbon capture technologies minimising the cost of supplying energy demand in the form of electricity, hydrogen, natural gas or synthetic methane across the power, heating, transportation and industry sectors whilst accounting for policy drivers, such as energy independence, carbon emissions reductions targets, or support schemes. The usefulness of the model is illustrated in a case study evaluating the potential of sector coupling via power-to-gas and carbon capture technologies to achieve deep decarbonisation targets in the Belgian context. Results, on the one hand, indicate that power-to-gas can only play a minor supporting role in cross-sector decarbonisation strategies in Belgium, as electrolysis plants are generally deployed in moderate quantities whilst methanation plants do not appear in any studied scenario. On the other hand, given the limited renewable potential, post-combustion and direct air carbon capture technologies clearly play an enabling role in any decarbonisation strategy. [less ▲]

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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 ▲]

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See detailUnveiling two new trichome-specific promoters of interest for metabolic engineering in Nicotiana tabacum
Pottier, Mathieu ULiege; Laterre, Raphaëlle; Van Wessem, Astrid et al

E-print/Working paper (2019)

Nicotiana tabacum has emerged as a suitable host for metabolic engineering of terpenoids and derivatives in tall glandular trichomes, which actively synthesize and secrete specialized metabolites. However ... [more ▼]

Nicotiana tabacum has emerged as a suitable host for metabolic engineering of terpenoids and derivatives in tall glandular trichomes, which actively synthesize and secrete specialized metabolites. However, implementation of an entire biosynthetic pathway in glandular trichomes requires the identification of trichome-specific promoters to appropriately drive the expression of the transgenes needed to set up the desired pathway. In this context, RT-qPCR analysis was carried out on wild-type N. tabacum plants to compare the expression pattern and level of NtRbS-T1 and NtMALD1, two newly identified genes expressed in glandular trichomes, with those of NtCYP71D16, NtCBTS2α, NtCPS2, NtLTP1, which were reported in the literature to be specifically expressed in glandular trichomes. The latter were previously investigated separately, preventing any accurate comparison of their expression level. We show that NtRbcS-T1 and NtMALD1 are specifically expressed in glandular trichomes just like NtCYP71D16, NtCBTS2α, NtCPS2, while NtLTP1 was also expressed in other leaf tissues as well as in the stem. Transcriptional fusions of all six promoters to the GUS-VENUS reporter gene were introduced in N. tabacum by Agrobacterium-mediated transformation. Most transgenic lines displayed GUS activity in tall glandular trichomes. In some transgenic lines, except for pNtLTP1:GUS-VENUS, this expression was specific. In other transgenic lines, GUS expression was extended to other tissues, probably resulting from a position effect during transgene integration. We discuss alternatives to overcome this lack of tissue specificity in some transgenic lines, should some of these promoters be used in the context of metabolic engineering in N. tabacum. [less ▲]

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See detailPanamá debe diseñar una hoja de ruta clara frente a China
Wintgens, Sophie ULiege

E-print/Working paper (2019)

Conceder prioridad a los intereses nacionales, diversificar los socios comerciales, defender la posición de Panamá como país neutral y fortalecer la democracia, son algunos aspectos que Panamá debe ... [more ▼]

Conceder prioridad a los intereses nacionales, diversificar los socios comerciales, defender la posición de Panamá como país neutral y fortalecer la democracia, son algunos aspectos que Panamá debe considerar para beneficiarse de la relación con China “sin perder soberanía”. [less ▲]

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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)

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See detailThe DAMPE excess and gamma-ray constraints
Laletin, Maxim ULiege; Belotsky, Konstantin; Solovyov, Maxim et al

E-print/Working paper (2019)

The direct measurements of the cosmic electron-positron spectrum around 1 TeV made by DAMPE have induced many theoretical speculations about possible excesses in the data above the standard astrophysical ... [more ▼]

The direct measurements of the cosmic electron-positron spectrum around 1 TeV made by DAMPE have induced many theoretical speculations about possible excesses in the data above the standard astrophysical predictions that might have the dark matter (DM) origin. These attempts mainly fall into two categories: i) DM annihilation (or decay) in the Galactic halo producing the broad spectrum excess; ii) DM annihilation in the nearby compact subhalo producing the sharp peak at 1.4 TeV. We investigate the gamma-ray emission accompanying e+e− production in DM annihilation, as well as various theoretical means to suppress the prompt radiation, such as specific interaction vertices or multi-cascade modes, and conclude that these attempts are in tension with various gamma-ray observations. We show that the DM explanations of the broad spectrum excess tend to contradict the diffuse isotropic gamma-ray background (IGRB), measured by Fermi-LAT, while the nearby subhalo scenario is constrained by nonobservation in the surveys, performed by Fermi-LAT, MAGIC and HESS. We also briefly review other types of gamma-ray constraints, which seem to rule out the DM interpretations of the DAMPE broad spectrum excess as well. [less ▲]

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See detailAuthentic ecology as an advanced stage of technological civilization
de Salle, Corentin; Ernst, Damien ULiege

E-print/Working paper (2019)

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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 ▲]

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See detailWill Deliveroo and Uber be captured by the proposed EU platform Regulation? You’d better watch out…
Van Cleynenbreugel, Pieter ULiege

E-print/Working paper (2019)

An analysis as to why Uber and Deliveroo could be excluded from the scope of application of the envisaged EU platform Regulation

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See detailStrongly interacting dark matter and the DAMA signal
Laletin, Maxim ULiege; Cudell, Jean-René ULiege

E-print/Working paper (2019)

We show that models of strongly interacting (SIMP) dark matter built to reproduce the DAMA signal actually cannot account for its time dependence. We discuss the constraints on this type of models coming ... [more ▼]

We show that models of strongly interacting (SIMP) dark matter built to reproduce the DAMA signal actually cannot account for its time dependence. We discuss the constraints on this type of models coming from direct detection experiments and study the propagation of thermalised dark matter particles in the ground for the allowed values of the parameters. We consider a simple 1D diffusion and a more detailed 3D diffusion. In both cases the predicted signal has either the wrong phase of the annual modulation or a much larger amplitude of the diurnal modulation. [less ▲]

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See detailVoiture électrique : 697.612 km pour devenir verte ! Vrai ou faux ?
Ernst, Damien ULiege

E-print/Working paper (2019)

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See detailElectric car: 697,612 km to become green! True or false?
Ernst, Damien ULiege

E-print/Working paper (2019)

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See detailRemembering Jean-Pierre Bourguignon, MD, PhD
Parent, Anne-Simone ULiege; Zoeller, R. Thomas; Geenen, Vincent ULiege et al

E-print/Working paper (2019)

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See detailInvest Smarter... All my Tweets on the Art & Science of Internet-Based Investing
Choffray, Jean-Marie ULiege

E-print/Working paper (2019)

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

“Invest smarter…” I started this project three years ago. After several hundred hours of reading, thinking and writing, here they are: “All my Tweets on The Art & Science of Internet-Based Investing.” While producing them, my goal was to “show you the way”; to share my observations on the evolution of the world and the behavior of the financial markets; and, to illustrate the key heuristics that I learned over the years, including the most recent, and turbulent, period. As, without any doubt, I am no Warren Buffett, feel free to disagree and develop your own theory of investing. Painful and solitary work... Success is at that price! And, based on what I did - and did not! - achieve, it shouldn’t be hard to do much better... That’s my wish for you! [less ▲]

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See detailIntroducing neuromodulation in deep neural networks to learn adaptive behaviours
Vecoven, Nicolas ULiege; Ernst, Damien ULiege; Wehenkel, Antoine ULiege et al

E-print/Working paper (2019)

In this paper, we propose a new deep neural network architecture, called NMD net, that has been specifically designed to learn adaptive behaviours. This architecture exploits a biological mechanism called ... [more ▼]

In this paper, we propose a new deep neural network architecture, called NMD net, that has been specifically designed to learn adaptive behaviours. This architecture exploits a biological mechanism called neuromodulation that sustains adaptation in biological organisms. This architecture has been introduced in a deep-reinforcement learning architecture for interacting with Markov decision processes in a meta-reinforcement learning setting where the action space is continuous. The deep-reinforcement learning architecture is trained using an advantage actor-critic algorithm. Experiments are carried on several test problems. Results show that the neural network architecture with neuromodulation provides significantly better results than state-of-the-art recurrent neural networks which do not exploit this mechanism. [less ▲]

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See detailReport on HOSTS survey return
Ertel, Steve; Hinz, Phil; Mennesson, Bertrand et al

E-print/Working paper (2019)

Observations for the HOSTS (Hunt for Observable Signatures of Terrestrial Systems) survey for warm dust around nearby stars (exozodiacal dust, i.e., dust in and near their habitable zones, HZs) have been ... [more ▼]

Observations for the HOSTS (Hunt for Observable Signatures of Terrestrial Systems) survey for warm dust around nearby stars (exozodiacal dust, i.e., dust in and near their habitable zones, HZs) have been completed in the first half of 2018 (during observing semester 2018A). The goal of HOSTS was to constrain the occurrence rate and typical level of exozodiacal dust around a sample of nearby starsin order to assess the risk imposed by this dust to future space missions attempting to directly image habitable exoplanets. We here report on the immediate conclusions of the survey relevant to this goal.Detailed descriptions of the HOSTS observing strategy, data reduction, and analysis together with detailed statistical results were provided by Ertel et al. (2018a). Here, we provide only a brief summary of these points and updates where necessary. In particular, we provide the final null measurements and derived HZ dust levels (zodi levels) for all observed stars and final statistics derived from those measurements. [less ▲]

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See detailThe homogeneous internal structure of CM-like asteroid (41) Daphne
Carry, B.; Vachier, F.; Berthier, J. et al

E-print/Working paper (2019)

Context. CM-like asteroids (Ch and Cgh classes) are a major population within the broader C-complex, encompassing about 10% of the mass of the main asteroid belt. Their internal structure has been ... [more ▼]

Context. CM-like asteroids (Ch and Cgh classes) are a major population within the broader C-complex, encompassing about 10% of the mass of the main asteroid belt. Their internal structure has been predicted to be homogeneous, based on their compositional similarity as inferred from spectroscopy (Vernazza et al., 2016, AJ 152, 154) and numerical modeling of their early thermal evolution (Bland & Travis, 2017, Sci. Adv. 3, e1602514). Aims. Here we aim to test this hypothesis by deriving the density of the CM-like asteroid (41) Daphne from detailed modeling of its shape and the orbit of its small satellite. Methods. We observed Daphne and its satellite within our imaging survey with the Very Large Telescope extreme adaptive-optics SPHERE/ZIMPOL camera (ID 199.C-0074, PI P. Vernazza) and complemented this data set with earlier Keck/NIRC2 and VLT/NACO observations. We analyzed the dynamics of the satellite with our Genoid meta-heuristic algorithm. Combining our high-angular resolution images with optical lightcurves and stellar occultations, we determine the spin period, orientation, and 3-D shape, using our ADAM shape modeling algorithm. Results. The satellite orbits Daphne on an equatorial, quasi-circular, prograde orbit, like the satellites of many other large main-belt asteroids. The shape model of Daphne reveals several large flat areas that could be large impact craters. The mass determined from this orbit combined with the volume computed from the shape model implies a density for Daphne of 1.77+/-0.26 g/cm3 (3 {\sigma}). This density is consistent with a primordial CM-like homogeneous internal structure with some level of macroporosity (~17%). Conclusions. Based on our analysis of the density of Daphne and 75 other Ch/Cgh-type asteroids gathered from the literature, we conclude that the primordial internal structure of the CM parent bodies was homogeneous. [less ▲]

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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 ▲]

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See detailLandscape-like Architecture Hiroshi Senju Museum as An Alternative to Placelessness
Van Rooyen, Xavier ULiege

E-print/Working paper (2019)

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See detailCo-Housing: The Challenge of Shared Spaces within a Shared Society
Van Rooyen, Xavier ULiege

E-print/Working paper (2019)

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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 ▲]

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See detailGuide d'utilisation de Zotero: Fonctionnalités de base de l'outil de gestion bibliographique
Dony, Christophe ULiege

E-print/Working paper (2019)

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See detailPhotovoltaic solar panel in Wallonia: Estimating the rebound effect
Boccard, Nicolas; Gautier, Axel ULiege

E-print/Working paper (2019)

In Wallonia (Belgium), the public support for residential solar photovoltaic panels has two interesting features. First, the subsidies for solar production, in the form of tradable green certificates ... [more ▼]

In Wallonia (Belgium), the public support for residential solar photovoltaic panels has two interesting features. First, the subsidies for solar production, in the form of tradable green certificates, were particularly generous which encouraged households to have large installations. Second, the region used a net metering system to record power exchanges with the grid. With net metering, the meter runs backwards when power is supplied to the grid. But, if production exceeds consumption on a yearly basis, the production surpluses are freely available for consumption. In this context, we test for a possible rebound effect. Based on a large sample of residential PV installation in Wallonia, we observe in our data and estimations, that a large proportion of households oversize their installation to benefit from the subsidies and, later consume most of their excess production. The effect is highly significant and production surpluses are almost entirely consumed. There are thus evidence of a strong increase in energy consumption by residential PV owners. [less ▲]

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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 (2019)

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See detailLa tour d'ivoire et la marée de merde: sur un texte de Simon Leys et son actualité
Thirion, Nicolas ULiege

E-print/Working paper (2019)

Le décret « définissant le paysage de l’enseignement supérieur et l’organisation académique des études », mieux connu sous l’appellation de « décret Paysage », constitue la traduction presque parfaite ... [more ▼]

Le décret « définissant le paysage de l’enseignement supérieur et l’organisation académique des études », mieux connu sous l’appellation de « décret Paysage », constitue la traduction presque parfaite, dans les limites de la Communauté française de Belgique, de certaines dérives qui affectent l’institution universitaire un peu partout dans le monde depuis un quart de siècle environ et qui, toutes, proviennent de deux tendances lourdes: l’utilitarisme à courte vue, d’un côté ; la démagogie racoleuse, de l’autre. Ce faisant, le décret "Paysage" consacre une vision de l’Université et, plus largement, de l’enseignement supérieur à contre-courant des principes et des croyances qui les ont fondés et les irriguaient encore jusqu’il y a peu. [less ▲]

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See detailClassification of load forecasting studies by forecasting problem to select load forecasting techniques and methodologies
Dumas, Jonathan ULiege; Cornélusse, Bertrand ULiege

E-print/Working paper (2018)

This article proposes a two-dimensional classification methodology to select the relevant forecasting tools developed by the scientific community based on a classification of load forecasting studies. The ... [more ▼]

This article proposes a two-dimensional classification methodology to select the relevant forecasting tools developed by the scientific community based on a classification of load forecasting studies. The inputs of the classifier are the articles of the literature and the outputs are articles classified into categories. The classification process relies on two couple of parameters that defines a forecasting problem. The temporal couple is the forecasting horizon and the forecasting resolution. The system couple is the system size and the load resolution. Each article is classified with key information about the dataset used and the forecasting tools implemented: the forecasting techniques (probabilistic or deterministic) and methodologies, the cleansing data techniques and the error metrics. This process is illustrated by reviewing and classifying thirty-four articles. [less ▲]

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See detailComputing the k-binomial complexity of the Thue–Morse word
Lejeune, Marie ULiege; Leroy, Julien ULiege; Rigo, Michel ULiege

E-print/Working paper (2018)

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See detailThe discovery of WASP-134b, WASP-134c, WASP-137b, WASP-143b and WASP-146b: three hot Jupiters and a pair of warm Jupiters orbiting Solar-type stars
Anderson, D. R.; Bouchy, F.; Brown, D. J. A. et al

E-print/Working paper (2018)

We report the discovery by WASP of five planets orbiting moderately bright ($V$ = 11.0-12.9) Solar-type stars. WASP-137b, WASP-143b and WASP-146b are typical hot Jupiters in orbits of 3-4 d and with ... [more ▼]

We report the discovery by WASP of five planets orbiting moderately bright ($V$ = 11.0-12.9) Solar-type stars. WASP-137b, WASP-143b and WASP-146b are typical hot Jupiters in orbits of 3-4 d and with masses in the range 0.68--1.11 $M_{\rm Jup}$. WASP-134 is a metal-rich ([Fe/H] = +0.40 $\pm$ 0.07]) G4 star orbited by two warm Jupiters: WASP-134b ($M_{\rm pl}$ = 1.41 $M_{\rm Jup}$; $P = 10.1$ d; $e = 0.15 \pm 0.01$; $T_{\rm eql}$ = 950 K) and WASP-134c ($M_{\rm pl} \sin i$ = 0.70 $M_{\rm Jup}$; $P = 70.0$ d; $e = 0.17 \pm 0.09$; $T_{\rm eql}$ = 500 K). From observations of the Rossiter-McLaughlin effect of WASP-134b, we find its orbit to be misaligned with the spin of its star ($\lambda = -44 \pm 10^\circ$). WASP-134 is a rare example of a system with a short-period giant planet and a nearby giant companion. In-situ formation or disc migration seem more likely explanations for such systems than does high-eccentricity migration. [less ▲]

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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 ▲]

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See detailCritical Time Windows for Renewable Resource Complementarity Assessment
Berger, Mathias ULiege; Radu, David-Constantin ULiege; Fonteneau, Raphaël ULiege et al

E-print/Working paper (2018)

This paper proposes a systematic framework to assess the complementarity of renewable resources over arbitrary geographical scopes and temporal scales which is particularly well-suited to exploit very ... [more ▼]

This paper proposes a systematic framework to assess the complementarity of renewable resources over arbitrary geographical scopes and temporal scales which is particularly well-suited to exploit very large data sets of climatological data. The concept of critical time windows is introduced, and a spatio-temporal criticality indicator is proposed, consisting in a parametrised family of scalar indicators quantifying the complementarity between renewable resources in both space and time. The criticality indicator is leveraged to devise a family of optimisation problems identifying sets of locations with maximum complementarity under arbitrary geographical deployment constraints. The applicability of the framework is shown in a case study investigating the complementarity between the wind regimes in continental western Europe and southern Greenland, and its usefulness in a power system planning context is demonstrated. Besides showing that the occurrence of low wind power production events can be significantly reduced on a regional scale by exploiting diversity in local wind patterns, results highlight the fact that aggregating wind power production sites located on different continents may result in a lower occurrence of system-wide low wind power production events and indicate potential benefits of intercontinental electrical interconnections. [less ▲]

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See detailDo balanced words have a short period?
Brauner, Nadia; Crama, Yves ULiege; Delaporte, Etienne et al

E-print/Working paper (2018)

We conjecture that each balanced word on N letters - either arises from a balanced word on two letters by expanding both letters with a congruence word, - or is D-periodic with D <= 2^N-1. Our conjecture ... [more ▼]

We conjecture that each balanced word on N letters - either arises from a balanced word on two letters by expanding both letters with a congruence word, - or is D-periodic with D <= 2^N-1. Our conjecture arises from extensive numerical experiments. It implies, for any fixed N, the finiteness of the number of balanced words on N letters which do not arise from expanding a balanced word on two letters. It refines a theorem of Graham and Hubert, which states that non-periodic balanced words are congruence expansions of balanced words on two letters. It also relates to Fraenkel's conjecture, which states that for N > 2, every balanced word with distinct densities d_1 > d_2 > ... > d_N satisfies d_i = 2^{N-i} / (2^N-1), since this implies that the word is D-periodic with D= 2^N-1. For N < 7, we provide a tentative list of the density vectors of balanced words which do not arise from expanding a balanced word with fewer letters. We prove that the list is complete for N=4 letters. We also prove that deleting a letter in a congruence word always produces a balanced word and this construction allows us to further reduce the list of density vectors that remains unexplained. Moreover, we prove that deleting a letter in an m-balanced word produces an (m+1)-balanced word, thus extending and simplifying a result of Sano et al. (2004). [less ▲]

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See detailLa République du Kosovo : le plus jeune Etat d’Europe
Lika, Liridon ULiege

E-print/Working paper (2018)

Detailed reference viewed: 20 (1 ULiège)
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See detailWASP-190b: Tomographic discovery of a transiting hot Jupiter
Temple, L. Y.; Hellier, C.; Anderson, D. R. et al

E-print/Working paper (2018)

We report the discovery of WASP-190b, an exoplanet on a 5.37-day orbit around an inflated F6 IV-V star with T_eff = 6400 $\pm$ 100 K, M$_{*}$ = 1.35 $\pm$ 0.05 M_sun and R$_{*}$ = 1.6 $\pm$ 0.1 R_sun. The ... [more ▼]

We report the discovery of WASP-190b, an exoplanet on a 5.37-day orbit around an inflated F6 IV-V star with T_eff = 6400 $\pm$ 100 K, M$_{*}$ = 1.35 $\pm$ 0.05 M_sun and R$_{*}$ = 1.6 $\pm$ 0.1 R_sun. The planet has a radius of R_p = 1.15 $\pm$ 0.09 R_Jup and a mass of M_p = 1.0 $\pm$ 0.1 M_Jup, making it a mildly inflated hot Jupiter. The orbit is also marginally misaligned with respect to the stellar rotation, with $\lambda$ = 21 $\pm$ 6$^{\circ}$ measured using Doppler tomography. We compare a Rossiter-McLaughlin analysis (involving radial velocity measurements) with the Doppler tomography method, and find that the latter provides a better constraint on $vsini_{*}$ and $\lambda$. [less ▲]

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See detailWASP-166b: a bloated super-Neptune transiting a V = 9 star
Hellier, Coel; Anderson, D. R.; Triaud, A. H. M. J. et al

E-print/Working paper (2018)

We report the discovery of WASP-166b, a super-Neptune planet with a mass of 0.1 Mjup and a bloated radius of 0.63 Rjup. It transits a V = 9.36, F9V star in a 5.44-d orbit that is aligned with the stellar ... [more ▼]

We report the discovery of WASP-166b, a super-Neptune planet with a mass of 0.1 Mjup and a bloated radius of 0.63 Rjup. It transits a V = 9.36, F9V star in a 5.44-d orbit that is aligned with the stellar rotation (lambda = -3 +/- 5 degrees). WASP-166b appears to be a rare object within the `Neptune desert'. The planet's low surface gravity and bright host star make it a promising target for atmospheric characterisation. There are variations in the radial-velocity measurements that might result from stellar magnetic activity. [less ▲]

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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 ▲]

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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 ▲]

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See detailLa tranquille pénétration chinoise en Amérique latine et Caraïbes
Kellner, Thierry; Wintgens, Sophie ULiege

E-print/Working paper (2018)

En 2008, la République populaire de Chine (RPC) publiait son premier Policy Paper définissant stratégiquement ses relations avec l’Amérique latine et les Caraïbes (ALC). Depuis, en l’espace d’une décennie ... [more ▼]

En 2008, la République populaire de Chine (RPC) publiait son premier Policy Paper définissant stratégiquement ses relations avec l’Amérique latine et les Caraïbes (ALC). Depuis, en l’espace d’une décennie, elle s’est affirmée comme un partenaire commercial et financier incontournable dans cette zone longtemps considérée comme l’arrière-cour de Washington. Pourtant, vus d’Europe, les intérêts et l’action de Pékin dans le sous-continent latino-américain restent encore largement méconnus, voire ignorés. Cet article a pour but d'en livrer un petit éclairage. [less ▲]

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See detailA low-density hot Jupiter in a near-aligned, 4.5-day orbit around a $V$ = 10.8, F5V star
Anderson, D. R.; Bouchy, F.; Brown, D. J. A. et al

E-print/Working paper (2018)

We report the independent discovery and characterisation of a hot Jupiter in a 4.5-d, transiting orbit around the star TYC 7282-1298-1 ($V$ = 10.8, F5V). The planet has been pursued by the NGTS team as ... [more ▼]

We report the independent discovery and characterisation of a hot Jupiter in a 4.5-d, transiting orbit around the star TYC 7282-1298-1 ($V$ = 10.8, F5V). The planet has been pursued by the NGTS team as NGTS-2b and by ourselves as WASP-179b. We characterised the system using a combination of photometry from WASP-South and TRAPPIST-South, and spectra from CORALIE (around the orbit) and HARPS (through the transit). We find the planet's orbit to be nearly aligned with its star's spin. From a detection of the Rossiter-McLaughlin effect, we measure a projected stellar obliquity of $\lambda = -19 \pm 6^\circ$. From line-profile tomography of the same spectra, we measure $\lambda = -11 \pm 5^\circ$. We find the planet to have a low density ($M_{\rm P}$ = 0.67 $\pm$ 0.09 $M_{\rm Jup}$, $R_{\rm P}$ = 1.54 $\pm$ 0.06 $R_{\rm Jup}$), which, along with its moderately bright host star, makes it a good target for transmission spectroscopy. We find a lower stellar mass ($M_*$ = $1.30 \pm 0.07$ $M_\odot$) than reported by the NGTS team ($M_*$ = $1.64 \pm 0.21$ $M_\odot$), though the difference is only $1.5$ $\sigma$. [less ▲]

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See detailWASP-189b: an ultra-hot Jupiter transiting the bright A star HR 5599 in a polar orbit
Anderson, D. R.; Temple, L. Y.; Nielsen, L. D. et al

E-print/Working paper (2018)

We report the discovery of WASP-189b: an ultra-hot Jupiter in a 2.72-d transiting orbit around the $V = 6.6$ A star WASP-189 (HR 5599). We detected periodic dimmings in the star's lightcurve, first with ... [more ▼]

We report the discovery of WASP-189b: an ultra-hot Jupiter in a 2.72-d transiting orbit around the $V = 6.6$ A star WASP-189 (HR 5599). We detected periodic dimmings in the star's lightcurve, first with the WASP-South survey facility then with the TRAPPIST-South telescope. We confirmed that a planet is the cause of those dimmings via line-profile tomography and radial-velocity measurements using the HARPS and CORALIE spectrographs. Those reveal WASP-189b to be an ultra-hot Jupiter ($M_{\rm P}$ = 2.13 $\pm$ 0.28 $M_{\rm Jup}$; $R_{\rm P}$ = 1.374 $\pm$ 0.082 $R_{\rm Jup}$) in a polar orbit ($\lambda = 89.3 \pm 1.4^\circ$; $\Psi = 90.0 \pm 5.8^\circ$) around a rapidly rotating A6IV-V star ($T_{\rm eff}$ = 8000 $\pm$ 100 K; $v_* \sin i_*$ $\approx$ 100 km\, s$^{-1}$). We calculate a predicted equilibrium temperature of $T_{\rm eql}$ = 2641 $\pm$ 34 K, assuming zero albedo and efficient redistribution, which is the third hottest for the known exoplanets. WASP-189 is the brightest known host of a transiting hot Jupiter and the third-brightest known host of any transiting exoplanet. We note that of the eight hot-Jupiter systems with $T_{\rm eff}$ $>$ 7000 K, seven have strongly misaligned orbits, and two of the three systems with $T_{\rm eff}$ $\geq$ 8000 K have polar orbits (the third is aligned). [less ▲]

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See detailNGTS-4b: A sub-Neptune Transiting in the Desert
West, Richard G.; Gillen, Edward; Bayliss, Daniel et al

E-print/Working paper (2018)

We report the discovery of NGTS-4b, a sub-Neptune-sized planet transiting a 13th magnitude K-dwarf in a 1.34d orbit. NGTS-4b has a mass M=$20.6\pm3.0$M_E and radius R=$3.18\pm0.26$R_E, which places it ... [more ▼]

We report the discovery of NGTS-4b, a sub-Neptune-sized planet transiting a 13th magnitude K-dwarf in a 1.34d orbit. NGTS-4b has a mass M=$20.6\pm3.0$M_E and radius R=$3.18\pm0.26$R_E, which places it well within the so-called "Neptunian Desert". The mean density of the planet ($3.45\pm0.95$g/cm^3) is consistent with a composition of 100% H$_2$O or a rocky core with a volatile envelope. NGTS-4b is likely to suffer significant mass loss due to relatively strong EUV/X-ray irradiation. Its survival in the Neptunian desert may be due to an unusually high core mass, or it may have avoided the most intense X-ray irradiation by migrating after the initial activity of its host star had subsided. With a transit depth of $0.13\pm0.02$%, NGTS-4b represents the shallowest transiting system ever discovered from the ground, and is the smallest planet discovered in a wide-field ground-based photometric survey. [less ▲]

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Peer Reviewed
See detailOn the efficiency of decentralized decision-making in self-dispatch power systems
Petitet, Marie; Perrot, Marie; Mathieu, Sébastien ULiege et al

E-print/Working paper (2018)

This paper focuses on market design options for operational balancing management in self-dispatch electric power systems. In particular, it investigates the most relevant timing for the balancing gate ... [more ▼]

This paper focuses on market design options for operational balancing management in self-dispatch electric power systems. In particular, it investigates the most relevant timing for the balancing gate closure, when competitors can no longer modify their decisions on the setting of controllable assets and when this responsibility is simultaneously transferred to the system operator. This discussion is central in the development and implementation of the European Electricity Balancing Guideline. Based on a multi-level simulation tool with a realistic modelling of short-term power system operations including informational asymmetry between market participants and the system operator, this paper proposes the first quantitative assessment of reducing the balancing gate closure time from one hour to 15 minutes ahead of the imbalance settlement period. For different environments (energy mix, power plant capabilities, outages, etc…), the results highlight that postponing the balancing gate closure time from one hour to 15 minutes increases the operational cost of the system. Based on robust and scalable results, we show that this difference is mainly due to a better coordination of the available resources by the central decision maker. [less ▲]

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See detailStyle de citation 'Université de Liège - Droit' : Guide d'utilisation
Cordier, Quentin ULiege; Desseilles, François ULiege

E-print/Working paper (2018)

Detailed reference viewed: 112 (26 ULiège)
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See detailUne petite collection de livres d’emblèmes
De Marco, Rosa ULiege

E-print/Working paper (2018)

Detailed reference viewed: 23 (5 ULiège)
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See detailLikelihood-free inference with an improved cross-entropy estimator
Stoye, Markus; Brehmer, Johann; Louppe, Gilles ULiege et al

E-print/Working paper (2018)

We extend recent work (Brehmer, et. al., 2018) that use neural networks as surrogate models for likelihood-free inference. As in the previous work, we exploit the fact that the joint likelihood ratio and ... [more ▼]

We extend recent work (Brehmer, et. al., 2018) that use neural networks as surrogate models for likelihood-free inference. As in the previous work, we exploit the fact that the joint likelihood ratio and joint score, conditioned on both observed and latent variables, can often be extracted from an implicit generative model or simulator to augment the training data for these surrogate models. We show how this augmented training data can be used to provide a new cross-entropy estimator, which provides improved sample efficiency compared to previous loss functions exploiting this augmented training data. [less ▲]

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See detailSocial Security Incentives in Belgium:An Analysis of Four Decades of Change
Fraikin, Anne-Lore ULiege; Jousten, Alain ULiege; Lefebvre, Mathieu ULiege

E-print/Working paper (2018)

The paper traces labor market reforms over the last four decades. It provides estimates of retirement incentives for a selected set of typical worker profiles across time and socioeconomic groups and ... [more ▼]

The paper traces labor market reforms over the last four decades. It provides estimates of retirement incentives for a selected set of typical worker profiles across time and socioeconomic groups and links these series to the labor market performance in Belgium. The results show that the numerous retirement and social security program reforms have had a marked impact on incentives at the micro level. At the aggregate level, results are less clear-cut given the extreme diversity of programs and features in the Belgian institutional context. [less ▲]

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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 ▲]

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See detailEfficient Probabilistic Inference in the Quest for Physics Beyond the Standard Model
Gunes Baydin, Atilim; Heinrich, Lukas; Bhimji, Wahid et al

E-print/Working paper (2018)

We present a novel framework that enables efficient probabilistic inference in large-scale scientific models by allowing the execution of existing domain-specific simulators as probabilistic programs ... [more ▼]

We present a novel framework that enables efficient probabilistic inference in large-scale scientific models by allowing the execution of existing domain-specific simulators as probabilistic programs, resulting in highly interpretable posterior inference. Our framework is general purpose and scalable, and is based on a cross-platform probabilistic execution protocol through which an inference engine can control simulators in a language-agnostic way. We demonstrate the technique in particle physics, on a scientifically accurate simulation of the tau lepton decay, which is a key ingredient in establishing the properties of the Higgs boson. High-energy physics has a rich set of simulators based on quantum field theory and the interaction of particles in matter. We show how to use probabilistic programming to perform Bayesian inference in these existing simulator codebases directly, in particular conditioning on observable outputs from a simulated particle detector to directly produce an interpretable posterior distribution over decay pathways. Inference efficiency is achieved via inference compilation where a deep recurrent neural network is trained to parameterize proposal distributions and control the stochastic simulator in a sequential importance sampling scheme, at a fraction of the computational cost of Markov chain Monte Carlo sampling. [less ▲]

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See detailDeep generative models for fast shower simulation in ATLAS
The ATLAS collaboration; Louppe, Gilles ULiege

E-print/Working paper (2018)

Detailed reference viewed: 92 (4 ULiège)
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See detailMachine Learning in High Energy Physics Community White Paper
Albertsson, Kim; Altoe, Piero; Anderson, Dustin et al

E-print/Working paper (2018)

Machine learning is an important research area in particle physics, beginning with applications to high-level physics analysis in the 1990s and 2000s, followed by an explosion of applications in particle ... [more ▼]

Machine learning is an important research area in particle physics, beginning with applications to high-level physics analysis in the 1990s and 2000s, followed by an explosion of applications in particle and event identification and reconstruction in the 2010s. In this document we discuss promising future research and development areas in machine learning in particle physics with a roadmap for their implementation, software and hardware resource requirements, collaborative initiatives with the data science community, academia and industry, and training the particle physics community in data science. The main objective of the document is to connect and motivate these areas of research and development with the physics drivers of the High-Luminosity Large Hadron Collider and future neutrino experiments and identify the resource needs for their implementation. Additionally we identify areas where collaboration with external communities will be of great benefit. [less ▲]

Detailed reference viewed: 39 (4 ULiège)
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See detailLa desconfianza es la peor antivacunas
Jamoulle, Marc ULiege; Pizzanelli, Miguel

E-print/Working paper (2018)

La cuestión de la vacunación contra el virus del papiloma humano, es por el momento, objeto de intensas discusiones. Uno podría pensar a primera vista que se trata de una cuestión puramente médica y, por ... [more ▼]

La cuestión de la vacunación contra el virus del papiloma humano, es por el momento, objeto de intensas discusiones. Uno podría pensar a primera vista que se trata de una cuestión puramente médica y, por lo tanto, científica. Sin embargo no lo es. Veremos que se trata en primer lugar de una pregunta o problema de tipo sociológico, luego económico y político y finalmente de tipo científico. Este asunto es tan urticante que se le ha llamado “la primera guerra de vacunas” (1,2) Nuestro objetivo no es detallar la historia reciente de la vacuna, sino recordar algunos hechos interesantes. La protección de la población y los individuos ha sido siempre una de las preocupaciones de la medicina. Como los médicos lidian permanentemente con el tiempo, llegar antes de un evento es el objetivo de la prevención, a pesar de que los pacientes aún no estén enfermos o aún no se vean afectados por un daño potencial. Estamos hablando de prevención primaria. Las vacunas y el descubrimiento de la higiene del agua han sido uno de los descubrimientos históricos más importantes contra los eventos que han trastornado la esperanza de vida de los humanos. Pero es la naturaleza médica de la vacunación, sus aspectos protectores y preventivos que han afectado más a la población. [less ▲]

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See detailOn the Stylized Fact of the Firm Size Distribution
Artige, Lionel ULiege; Reginster, Alexandre ULiege

E-print/Working paper (2018)

Detailed reference viewed: 54 (10 ULiège)
Peer Reviewed
See detailRoland Barthes, moderne, antimoderne, postmoderne, après-moderne ?
Demoulin, Laurent ULiege

E-print/Working paper (2018)

Tentative de réponse à Antoine Compagnon qui considère dans Les Antimodernes de Joseph de Maistre à Roland Barthes (Gallimard, coll. Bibliothèques des idées, 2005) que Roland Barthes est un penseur ... [more ▼]

Tentative de réponse à Antoine Compagnon qui considère dans Les Antimodernes de Joseph de Maistre à Roland Barthes (Gallimard, coll. Bibliothèques des idées, 2005) que Roland Barthes est un penseur antimoderne. [less ▲]

Detailed reference viewed: 37 (1 ULiège)
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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: 27 (1 ULiège)
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See detailDoes Coriolis force influence the flow in shallow reservoirs?
Dewals, Benjamin ULiege

E-print/Working paper (2018)

Detailed reference viewed: 18 (0 ULiège)
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See detailLes progrès en immunologie sont à la base des plus grands succès médicaux
Geenen, Vincent ULiege

E-print/Working paper (2018)

Detailed reference viewed: 15 (0 ULiège)
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See detailGradient Energy Matching for Distributed Asynchronous Gradient Descent
Hermans, Joeri ULiege; Louppe, Gilles ULiege

E-print/Working paper (2018)

Distributed asynchronous SGD has become widely used for deep learning in large-scale systems, but remains notorious for its instability when increasing the number of workers. In this work, we study the ... [more ▼]

Distributed asynchronous SGD has become widely used for deep learning in large-scale systems, but remains notorious for its instability when increasing the number of workers. In this work, we study the dynamics of distributed asynchronous SGD under the lens of Lagrangian mechanics. Using this description, we introduce the concept of energy to describe the optimization process and derive a sufficient condition ensuring its stability as long as the collective energy induced by the active workers remains below the energy of a target synchronous process. Making use of this criterion, we derive a stable distributed asynchronous optimization procedure, GEM, that estimates and maintains the energy of the asynchronous system below or equal to the energy of sequential SGD with momentum. Experimental results highlight the stability and speedup of GEM compared to existing schemes, even when scaling to one hundred asynchronous workers. Results also indicate better generalization compared to the targeted SGD with momentum. [less ▲]

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Peer Reviewed
See detailInternet Archive, Google et l’édition clandestine mosane des Lumières
Droixhe, Daniel ULiege

E-print/Working paper (2018)

Detailed reference viewed: 26 (7 ULiège)
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See detailMining gold from implicit models to improve likelihood-free inference
Brehmer, Johann; Louppe, Gilles ULiege; Pavez, Juan et al

E-print/Working paper (2018)

Simulators often provide the best description of real-world phenomena; however, they also lead to challenging inverse problems because the density they implicitly define is often intractable. We present a ... [more ▼]

Simulators often provide the best description of real-world phenomena; however, they also lead to challenging inverse problems because the density they implicitly define is often intractable. We present a new suite of simulation-based inference techniques that go beyond the traditional Approximate Bayesian Computation approach, which struggles in a high-dimensional setting, and extend methods that use surrogate models based on neural networks. We show that additional information, such as the joint likelihood ratio and the joint score, can often be extracted from simulators and used to augment the training data for these surrogate models. Finally, we demonstrate that these new techniques are more sample efficient and provide higher-fidelity inference than traditional methods. [less ▲]

Detailed reference viewed: 16 (2 ULiège)
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Peer Reviewed
See detailLarge-Scale Land Acquisitions for Agricultural Development in Myanmar: A Review of Past and Current Processes
San Thein; Diepart, Jean-Christophe ULiege; Hlwan Moe et al

E-print/Working paper (2018)

Detailed reference viewed: 30 (3 ULiège)
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See detailLes révolutionnaires, protecteurs du système ? Le Grand Soir est reporté à demain
Nossent, Jérôme ULiege

E-print/Working paper (2018)

En 1969, Georges Lavau, constitutionaliste et sociologue français, propose une analyse de la fonction du parti communiste français (PCF) dans une perspective systémique. Pour construire son modèle ... [more ▼]

En 1969, Georges Lavau, constitutionaliste et sociologue français, propose une analyse de la fonction du parti communiste français (PCF) dans une perspective systémique. Pour construire son modèle d’analyse, il s’inspire de l’approche de David Easton, notamment concernant la définition donnée de ce qu’est un système politique. Dans le prolongement de David Easton, Georges Lavau considère qu’un parti politique peut ou non contribuer au maintien du système politique en fonction des rôles qu’il endosse (volontairement ou indépendamment de sa volonté, voire inconsciemment). Partant, cette fois-ci de la typologie de Théodore Lowi qui assigne deux fonctions possibles à un parti politique, légitimation et stabilisation du système politique, d’une part, soutien des politiques publiques d’autre part, Georges Lavau propose une troisième fonction : la fonction tribunitienne. [less ▲]

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See detailConstraining Effective Field Theories with Machine Learning
Brehmer, Johann; Cranmer, Kyle; Louppe, Gilles ULiege et al

E-print/Working paper (2018)

We present powerful new analysis techniques to constrain effective field theories at the LHC. By leveraging the structure of particle physics processes, we extract extra information from Monte-Carlo ... [more ▼]

We present powerful new analysis techniques to constrain effective field theories at the LHC. By leveraging the structure of particle physics processes, we extract extra information from Monte-Carlo simulations, which can be used to train neural network models that estimate the likelihood ratio. These methods scale well to processes with many observables and theory parameters, do not require any approximations of the parton shower or detector response, and can be evaluated in microseconds. We show that they allow us to put significantly stronger bounds on dimension-six operators than existing methods, demonstrating their potential to improve the precision of the LHC legacy constraints. [less ▲]

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See detailA Guide to Constraining Effective Field Theories with Machine Learning
Brehmer, Johann; Cranmer, Kyle; Louppe, Gilles ULiege et al

E-print/Working paper (2018)

We develop, discuss, and compare several inference techniques to constrain theory parameters in collider experiments. By harnessing the latent-space structure of particle physics processes, we extract ... [more ▼]

We develop, discuss, and compare several inference techniques to constrain theory parameters in collider experiments. By harnessing the latent-space structure of particle physics processes, we extract extra information from the simulator. This augmented data can be used to train neural networks that precisely estimate the likelihood ratio. The new methods scale well to many observables and high-dimensional parameter spaces, do not require any approximations of the parton shower and detector response, and can be evaluated in microseconds. Using weak-boson-fusion Higgs production as an example process, we compare the performance of several techniques. The best results are found for likelihood ratio estimators trained with extra information about the score, the gradient of the log likelihood function with respect to the theory parameters. The score also provides sufficient statistics that contain all the information needed for inference in the neighborhood of the Standard Model. These methods enable us to put significantly stronger bounds on effective dimension-six operators than the traditional approach based on histograms. They also outperform generic machine learning methods that do not make use of the particle physics structure, demonstrating their potential to substantially improve the new physics reach of the LHC legacy results. [less ▲]

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See detailCommuting within the EU? Take your Netflix content with you!
Van Cleynenbreugel, Pieter ULiege

E-print/Working paper (2018)

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See detailCustomer ratings as a vector for discrimination in employment relations? Pathways and pitfalls for legal remedies
Ducato, Rossana; Kullmann, Miriam; Rocca, Marco ULiege

E-print/Working paper (2018)

The use of customer ratings to evaluate worker performance is increasingly worrisome because of its widespread use in the gig-economy. As scholars in computer and social sciences denounce, this practice ... [more ▼]

The use of customer ratings to evaluate worker performance is increasingly worrisome because of its widespread use in the gig-economy. As scholars in computer and social sciences denounce, this practice entails the risk of producing discriminatory outcomes, by reproducing biases existing in society. By drawing an analogy with discriminatory practices adopted by an employer to satisfy its customers’ preferences, we propose a legal analysis of this phenomenon grounded in EU non-discrimination law. Thus, we first analyse the issues related to the application of non-discrimination law to (alleged) self-employed workers. Then, we address the lack of access for the individual worker to the data regarding customers’ ratings. We conclude by arguing that the use of customer ratings should be considered as a suspect criterion, while the current (EU) non-discrimination laws should be modernised through a clearer inclusion of (alleged) self-employed workers. [less ▲]

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See detailThe effect of initial water distribution and spatial resolution on the interpretation of ERT monitoring of water infiltration in a landfill cover
Dumont, Gael; Pilaswki, Tamara; Hermans, Thomas et al

E-print/Working paper (2018)

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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 ▲]

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See detailL’économie sur le sentier de la guerre : la bataille des normes
Wintgens, Sophie ULiege

E-print/Working paper (2018)

On entend souvent cette idée selon laquelle le monde se dérégularise mais en réalité, le monde a rarement connu une telle inflation de normes techniques, commerciales ou environnementales qui définissent ... [more ▼]

On entend souvent cette idée selon laquelle le monde se dérégularise mais en réalité, le monde a rarement connu une telle inflation de normes techniques, commerciales ou environnementales qui définissent les règles de l'économie. Alors à quoi ressemble cette bataille entre puissances normatives? [less ▲]

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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 ▲]

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See detailLes politiques de mémoire, dans quels buts?
Nossent, Jérôme ULiege

E-print/Working paper (2018)

Une large question, fondamentale dans le cadre de nos sociétés contemporaines[4], est à l’origine des réflexions développées dans l’ouvrage : « À quoi servent les politiques de mémoire ? ». Les auteurs ... [more ▼]

Une large question, fondamentale dans le cadre de nos sociétés contemporaines[4], est à l’origine des réflexions développées dans l’ouvrage : « À quoi servent les politiques de mémoire ? ». Les auteurs définissent ces dernières comme des « actions qui, pour agir sur la société et ses membres, et les transformer, mobilisent le rappel du passé » (Gensburger et Lefranc, 2017, 15). Sont ainsi interrogées les intentions des initiateurs de politiques de mémoire, celles des porteurs de mémoire susceptibles de rejoindre ces initiatives et enfin, dans une certaine mesure, les effets de ces politiques. [less ▲]

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See detailSchéma de Développement du Territoire: Contribution de la CPDT à l'analyse contextuelle
Bianchet, Bruno ULiege; Hanin, Yves; Godart, Marie-Françoise et al

E-print/Working paper (2018)

This research note from the walloon Permanent Conference of Territorial Development (CPDT) presents the Conference's contributions to the territorial analysis prior to the implementation of the ... [more ▼]

This research note from the walloon Permanent Conference of Territorial Development (CPDT) presents the Conference's contributions to the territorial analysis prior to the implementation of the Development Plan for the Territory of Wallonia. [less ▲]

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Peer Reviewed
See detailSeeking to regulate Uber? Why not rely on Article 101 TFEU...
Van Cleynenbreugel, Pieter ULiege

E-print/Working paper (2018)

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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 ▲]

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See detailReview of urban flood experimental models and preliminary design of a laboratory setup of urban flooding
Li, Xuefang ULiege; Erpicum, Sébastien ULiege; Archambeau, Pierre ULiege et al

E-print/Working paper (2018)

In this study, we will investigate a study on an urban flood experimental model. Firstly, a literature review of urban flood experimental models is addressed to summarize the studies in this sector ... [more ▼]

In this study, we will investigate a study on an urban flood experimental model. Firstly, a literature review of urban flood experimental models is addressed to summarize the studies in this sector (Section 2). Next, a strategy of experimental model design will be proposed (section 3.1). Particularly, we are interested in analyzing the influence of model distortion to the flow characteristics (Section 3) and the effect of the interaction between surface flow and underground space (Section 4). [less ▲]

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See detailLe phénomène interrégional dans le Global South: quel cadre conceptuel pour une réalité empirique plurielle? Le cas du dialogue afro-sud- américain.
Mvengou Cruzmerino, Martine Colette ULiege

E-print/Working paper (2018)

La mise en place de dynamiques interrégionales dans le Global South a participé à la mutation de la physionomie de la scène internationale dès le début du XXIe siècle, offrant ainsi aux régions du Sud de ... [more ▼]

La mise en place de dynamiques interrégionales dans le Global South a participé à la mutation de la physionomie de la scène internationale dès le début du XXIe siècle, offrant ainsi aux régions du Sud de nouveaux espaces de socialisation et de dialogue. Par ailleurs, ces interactions interrégionales Sud-Sud renvoient à une réalité empirique plurielle dont l’étude reste marginalisée au sein de la littérature sur l’interregionalisme. Dès lors, la présente contribution s’interroge sur l’usage et la pratique qui est fait de l’espace inter régional dans le Global South et questionne la mise en place d’un cadre conceptuel capable de mettre en lumière les différents enjeux et logiques qui structurent lesdits processus ineterregionaux. En soulignant le paradoxe épistémologique qui caractérise l’analyse des processus interrégionaux au Sud, à savoir le fait de rassembler des réalités plurielles et à la fois de manquer de cadre d’analyse susceptible d’aborder les enjeux de cet usage spécifique, cette contribution se penche sur le cas des relations interrégionales afro-sud-américaines. Ainsi, à partir de cette étude de cas, il est présenté une approche éclectique qui vise à intégrer le concept de Coopération Sud-Sud dans l’étude desdits processus notamment à travers la notion d’interrégionalisme Sud-Sud. [less ▲]

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See detailEquilibrium selection and stability in dynamic core-periphery models with heterogeneous preferences
Delloye, Justin; Peeters, Dominique; Tharakan, Joseph ULiege

E-print/Working paper (2018)

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See detailLaw, New Technologies & Artificial Intelligence. Session 2: Regulation of data
Mansvelt, Valérie ULiege

E-print/Working paper (2018)

After a general presentation of the context data and privacy regulation by Christian D’Cunha, the different speakers covering this course discussed the main grounds of the GDPR (Laurent De Muyter ) as ... [more ▼]

After a general presentation of the context data and privacy regulation by Christian D’Cunha, the different speakers covering this course discussed the main grounds of the GDPR (Laurent De Muyter ) as well as other relevant legislation for data regulation followed by some study cases (Inge Graef ). The importance of regulation of data is undeniable, as it is at the core of artificial intelligence (A.I.). Indeed, it requires big amounts of various data and the velocity of data. The most personal the data is, the most valuable it is. This collect of data is made possible by an increasing amount of connected devices. Therefore, there is security issues that arise (risk of hacking and losing data for example). This course aims at giving a better understanding of the scope of the various regulatory instruments. [less ▲]

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See detailTowards a Typology of Business Models in the Biotechnology Industry
Segers, Jean Pierre ULiege

E-print/Working paper (2018)

The purpose of this paper is to identify a selection of key business models - “typology” - applied in the biotechnology industry. The focus is on the differences between traditional/closed or stand-alone ... [more ▼]

The purpose of this paper is to identify a selection of key business models - “typology” - applied in the biotechnology industry. The focus is on the differences between traditional/closed or stand-alone business models opposed to open or networked business models. A number of illustrative case studies and good practices are presented to show that new biotechnology firms are gradually adopting a “best of both worlds” strategy, with both closed business models and open, networked models as a way for gaining access to the market, in close collaboration with large global pharmaceutical companies. The case firms and good practices are taken from a recent country study for Belgium. [less ▲]

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See detailSmart Equity Investing: Implementing Risk Optimization Techniques on Strategic Beta Portfolios
Fays, Boris ULiege; Lambert, Marie ULiege; Nicolas, Papageorgiou

E-print/Working paper (2018)

We examine the performance of risk-optimization techniques on equity style portfolios. To form these portfolios, also called Strategic Beta factors by practitioners and data providers, we group stocks ... [more ▼]

We examine the performance of risk-optimization techniques on equity style portfolios. To form these portfolios, also called Strategic Beta factors by practitioners and data providers, we group stocks based on size, value and momentum characteristics through either independent or dependent sorting. Overall, performing risk-oriented strategies on style portfolios constructed with a dependent sort deliver greater abnormal returns. On average, we observe these strategies to significantly outperform 42% of the risk-oriented ETFs listed on US exchanges, compared to 31% when the risk-oriented strategies are performed on portfolios formed with an independent sort. We attribute the outperformance yielded by dependent sorting to the fact that it provides a better stratification of the set of stocks’ opportunity and diversification properties. [less ▲]

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See detailThe First Post-Kepler Brightness Dips of KIC 8462852
Boyajian, Tabetha S.; Alonso, Roi; Ammerman, Alex et al

E-print/Working paper (2018)

We present a photometric detection of the first brightness dips of the unique variable star KIC 8462852 since the end of the Kepler space mission in 2013 May. Our regular photometric surveillance started ... [more ▼]

We present a photometric detection of the first brightness dips of the unique variable star KIC 8462852 since the end of the Kepler space mission in 2013 May. Our regular photometric surveillance started in October 2015, and a sequence of dipping began in 2017 May continuing on through the end of 2017, when the star was no longer visible from Earth. We distinguish four main 1-2.5% dips, named "Elsie," "Celeste," "Skara Brae," and "Angkor", which persist on timescales from several days to weeks. Our main results so far are: (i) there are no apparent changes of the stellar spectrum or polarization during the dips; (ii) the multiband photometry of the dips shows differential reddening favoring non-grey extinction. Therefore, our data are inconsistent with dip models that invoke optically thick material, but rather they are in-line with predictions for an occulter consisting primarily of ordinary dust, where much of the material must be optically thin with a size scale <<1um, and may also be consistent with models invoking variations intrinsic to the stellar photosphere. Notably, our data do not place constraints on the color of the longer-term "secular" dimming, which may be caused by independent processes, or probe different regimes of a single process. [less ▲]

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See detailAfrique du Sud, les défis énergétiques et miniers d'un pays émergent
Merenne-Schoumaker, Bernadette ULiege

E-print/Working paper (2018)

Premier pays du continent africain par son développement économique, l’Afrique du Sud n’en est pas moins confrontée à plusieurs défis économiques parmi lesquels les secteurs de l’énergie et du minier ... [more ▼]

Premier pays du continent africain par son développement économique, l’Afrique du Sud n’en est pas moins confrontée à plusieurs défis économiques parmi lesquels les secteurs de l’énergie et du minier occupent une place de choix. En effet, le pays est fortement dépendant du charbon qui engendre différents problèmes économiques, sociaux et environnementaux. Le premier défi est de diversifier le mix énergétique et de réussir la transition énergétique nationale. Le second défi est économique et social : alors que le secteur minier joue un rôle majeur (2016 : 7,3 % du PIB national, plus de 455 000 emplois directs), il est en difficulté depuis trois ans. Sa relance est d’autant plus importante que le pays est menacé par la récession et que le taux de chômage progresse et dépasse actuellement 27 %. A travers l’analyse des défis énergétiques et miniers du pays, l’article tente non seulement de dresser un bilan des problèmes rencontrés par les deux secteurs mais encore de leurs potentialités et de pistes pour l’avenir. Le cas de l’Afrique du Sud est ainsi assez exemplaire des défis auxquels doit faire face un pays émergent, même si celui-ci est un BRICS. [less ▲]

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See detailAfgelopen decennium 21% meer Waalse leerlingen in het Vlaamse secundair onderwijs
Proesmans, Maxim ULiege

E-print/Working paper (2018)

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See detailAntoinette Desmoulins
Piront, Julie ULiege

E-print/Working paper (2018)

Detailed reference viewed: 17 (1 ULiège)
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See detailL’Histoire: un déterminant des comportements électoraux
Nossent, Jérôme ULiege

E-print/Working paper (2018)

Dans son « Étude électorale de certaines structure ou caractéristiques historiques », Marcel Hotterbeex propose une analyse des relations pouvant être établies entre les caractéristiques historiques ou ... [more ▼]

Dans son « Étude électorale de certaines structure ou caractéristiques historiques », Marcel Hotterbeex propose une analyse des relations pouvant être établies entre les caractéristiques historiques ou cultuelles de certaines communes belges et les résultats électoraux dans celles-ci. Cette étude s’inscrit dans une réflexion plus large concernant les résultats de partis régionaux et la conscience régionaliste des populations. [less ▲]

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See detail‘Crossovers’ in the Flemish education system: An exploratory study
Proesmans, Maxim ULiege

E-print/Working paper (2018)

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See detail« Proudhon, le premier pragmatiste? Petite histoire de l’autre sociologie »
Frère, Bruno ULiege

E-print/Working paper (2018)

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See detailSolidarity economy and its anarchist grammar
Frère, Bruno ULiege

E-print/Working paper (2018)

‘Solidarity economy’, a widely used term for which the most common French equivalent is economie solidaire, is generally thought of as comprising five distinct classes of activity : Micro-finance, Local ... [more ▼]

‘Solidarity economy’, a widely used term for which the most common French equivalent is economie solidaire, is generally thought of as comprising five distinct classes of activity : Micro-finance, Local Exange Trading Systems, proximity services, organic community supported agriculture and fairtrade distributions. Because they try to answer to the Aristotelian theoretical question “what can we do to live harmoniously together?”, these solidarity initiatives are deeply political in the philosophical sense of the term. They galvanize civic commitment at the “micro” level. But today, an important question arises regarding the kind of formal political institution that would speak in the name of all these initiatives. In France, some intellectuals who have an interest in these solidarity initiatives see them as new economic models with the potential to solve the current financial crisis, and they are eager for academic specialists and leaders of the movement to achieve some kind of consensus about the kind of concrete political identity such initiatives may be expected to generate. However this paper studies their way of establishing a basis for moving from micro level initiatives to substantial “macro” polity unity. Using the insights of french pragmatic sociology, and particularly the notion of grammar of justification, it aims to understand what the obstacles to this aim being realised are. [less ▲]

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See detailDiagram, the machine abstraite of contemporary architecture
Van Rooyen, Xavier ULiege

E-print/Working paper (2018)

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See detailGamma Trading Skills in Hedge Funds
Fays, Boris ULiege; Hübner, Georges ULiege; Lambert, Marie ULiege

E-print/Working paper (2018)

This paper explores the gamma trading, timing and managerial skills of individual hedge funds across categories. We replicate the non-linear payoffs of hedge funds with traded options, with the option ... [more ▼]

This paper explores the gamma trading, timing and managerial skills of individual hedge funds across categories. We replicate the non-linear payoffs of hedge funds with traded options, with the option features being endogenously defined in our replication model. On top of providing a flexible tool to create individual benchmarks for the payoff curvature of hedge fund, the model helps assigning hedge fund styles into three categories: directional with market timing skills, non-directional and market timers. Overall, our empirical results show that, on 30% of replicated funds in our sample (10,958 funds), there is no evidence of the presence of selection skills once a fund performance is adjusted with respect to the option-based benchmark and the traditional option-based factors of Agarwal and Naik (2004). This research has an incremental potential to stimulate additional research in the field of hedge funds performance replication through passive strategies. [less ▲]

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