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See detailHedge fund styles and macroeconomic uncertainty
Platania, Federico ULg; Lambert, Marie ULg

E-print/Working paper (in press)

This paper examines the dynamic trading strategies implemented by hedge fund managers using a Kalman filter of hedge fund betas across styles. We further investigate the risk drivers of dynamic trades ... [more ▼]

This paper examines the dynamic trading strategies implemented by hedge fund managers using a Kalman filter of hedge fund betas across styles. We further investigate the risk drivers of dynamic trades, examining which conditioning/macroeconomic variables strongly lead the time variation in fund trades. We report the significance of macroeconomic factors such as interest rates, dividend yield, GDP growth and US unemployment. We show that hedge fund managers do control the intensity of their exposures according to economic uncertainty and that differences between up- and down-market regimes can be observed. Commonly, Hedge funds tend to dislike high-dividend paying stocks. Besides, all hedge fund styles are shown to display pro-cyclical exposures towards directional equity factors as well as credit and liquidity risks. Small growth stocks, however, are revealed to be crisis investments whose allocation increases with unemployment, inflation or volatility. As volatility increases, the value of growth options embedded into growth stocks indeed increases. Growth stocks are shown to hedge market reversals and volatility. The outperformance of growth companies in recessions might also relate to their cost flexibility. Allocation to small stocks embed strong micro risks and might also constitute a hedge in economic slowdowns. This might explain why some funds with such a particular investment focus appear to be countercyclical. [less ▲]

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See detailSostanza e forma nella tradizione del romanzo arturiano in prosa
Leonardi, Lino; Morato, Nicola ULg

E-print/Working paper (in press)

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See detailMarket efficiency and hedge fund trading strategies
Platania, Federico ULg; Lambert, Marie ULg; Papageorgiou, Nicolas

E-print/Working paper (in press)

Stock and option markets can at times reflect differing information. We identify three reasons for the presence of these periods of "disagreement" between the cash and derivatives markets: 1) high ... [more ▼]

Stock and option markets can at times reflect differing information. We identify three reasons for the presence of these periods of "disagreement" between the cash and derivatives markets: 1) high volatility and noise trading; 2) high level of risk aversion; 3) speculation versus hedging trades. This paper investigates the role that hedge funds, a proxy for sophisticated investors, play in the price discovery process between stock and option markets and the disagreement/agreement periods. We observe that a disparity in information between the two markets is often associated with deleveraging in directional exposures and reversal strategies. Posterior to the event, active tactical asset allocation in small and value factor investing takes place. We investigate four specific macro events which resulted in significant rebalancing by hedge fund manegers: the Thai Baht depreciation, the Dot-com bubble, the credit crunch and the Nasdaq correction. [less ▲]

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See detailBack to materialism Reflections on Marx’s labour, praxis, cooperative and libertarian socialism in the 19th century
Frère, Bruno ULg

E-print/Working paper (2017)

From Marx to Althusser, the materialist approach has tended to assume that individuals (that is, workers, proletarians and other social actors), unconsciously reproduce the social structures of capitalism ... [more ▼]

From Marx to Althusser, the materialist approach has tended to assume that individuals (that is, workers, proletarians and other social actors), unconsciously reproduce the social structures of capitalism which alienate them. It is assumed that individuals accept the conditions forced upon them and no longer seek to rebel against a world which substantially impoverishes their labour, their spirit and their creativity. In this paper, I will try to show that by dint of favouring almost exclusively Marx's concept of alienation, there is a considerable risk that materialist thought will adopt only a negative path. Whilst I acknowledge Marx’s significance to materialism, I wish to argue that his stance should be combined with that of the anarchist and libertarian French thinker Proudhon. Proudhon has succeeded in presenting a conception of the worker as more than just alienated. Workers can also cooperate and experience a reciprocity seemingly at odds with the character of capitalism. Under Proudhon’s influence materialism takes a positive turn, enabling us to avoid falling into the utopianism that the theory of social economy employs to critique capitalism – a utopianism that renders its critique even less effective than that of Marx. [less ▲]

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See detailHow to account for new forms of resistance to domination: An argument for a materialist renewal in European social theory
Frère, Bruno ULg; Tulle, Emmanuelle

E-print/Working paper (2017)

Many significant intellectual developments have taken place in 20th century European social theories. Notably the first Frankfurt School and Bourdieu’s work have successfully shown how workers, social ... [more ▼]

Many significant intellectual developments have taken place in 20th century European social theories. Notably the first Frankfurt School and Bourdieu’s work have successfully shown how workers, social actors, etc. are alienated or dominated by capitalist social structures. But according to Habermas, neither perspective successfully allows for the possibility that people could contribute to their own emancipation. The emergence of new forms of social resistance to domination such as those embodied by the Indignados, Anonymous, Femen, the practitioners of alternative economy, movements of unemployed people or illegals compels us to envisage the possibility for emancipation, but how? In this paper we explore opportunities for accounting for this by considering the work of a range of other European social theorists, more specifically Boltanski whose critical intent is embodied in his pragmatic sociology, and evident in his coining and use of the concept of the world. In addition we will consider Latour’s own pragmatic stance as we believe that despite his disinterest in new social movements, his work, informed by pure immanence, might offer potential solutions. But we would argue that even in these innovations there is either a persistent tendency to imagine emancipation primarily as a return to some ideal state or a lack of critical engagement with alienation. In response, we propose a materialist renewal, which will lead us to ponder on the political role of sociologists. [less ▲]

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See detailBerge-acyclic multilinear 0-1 optimization problems
Buchheim, Christoph; Crama, Yves ULg; Rodriguez Heck, Elisabeth ULg

E-print/Working paper (2016)

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See detailPotential, opportunities and benefits of electric vehicles as frequency regulation resources
Glavic, Mevludin ULg; Alvarado, Fernando

E-print/Working paper (2016)

Any imbalance between electric power supply and demand results in power system frequency deviations from its nominal value. Frequency regulation is one of the most important services that regional system ... [more ▼]

Any imbalance between electric power supply and demand results in power system frequency deviations from its nominal value. Frequency regulation is one of the most important services that regional system operators perform to ensure reliable system operation. Traditional power supply sources such as generators are usually automatically modulated to help balance generation and demand by adjusting their output based in part on system frequency. As a result of the decreased inertia of the system caused by decommissioning of traditional power plants and the increase in the penetration of renewable energy sources, the increased use of demand side controls for the purpose of frequency regulation is receiving increased attention. Demand control can provide fast response to any imbalance. This opens up the possibility for Electric Vehicles (EVs) to be used as frequency regulation grid resources. This write-up discusses the potential, opportunities and benefit of doing so. [less ▲]

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See detailTweeting is not investing! But...
Choffray, Jean-Marie ULg

E-print/Working paper (2016)

So, here we are! Hundreds of Tweets on The Art and Science of Investing to “show you the way”, to share some observations on the markets and their behavior, and to illustrate the key heuristics that I ... [more ▼]

So, here we are! Hundreds of Tweets on The Art and Science of Investing to “show you the way”, to share some observations on the markets and their behavior, and to illustrate the key heuristics that I learned over the last twenty years. As, without any doubt, I am no Warren Buffett, feel free to disagree and develop you 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 better... That’s my wish for you! [less ▲]

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See detailLa Cour pénale internationale et les entorses aux droits essentiels des personnes privées de liberté
Deprez, Christophe ULg

E-print/Working paper (2016)

Ce texte propose un bref aperçu des faiblesses de la pratique de la Cour pénale internationale en matière de privation de liberté.

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See detailIT formulae for gamma target: mutual information and relative entropy
Arras, Benjamin ULg; Swan, Yvik ULg

E-print/Working paper (2016)

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See detailLARCH: A package for estimating multinomial, nested, and cross-nested logit models that account for semi-aggregate data
Newman, Jeffrey; Lurkin, Virginie ULg; Garrow, Laurie

E-print/Working paper (2016)

We present a summary of important computational issues and opportunities that arise from the use of semi-aggregate data (where the explanatory data for choice scenarios are not necessarily unique for each ... [more ▼]

We present a summary of important computational issues and opportunities that arise from the use of semi-aggregate data (where the explanatory data for choice scenarios are not necessarily unique for each decision-maker) in discrete choice models. This data feature is commonly encountered with large transactional databases that have limited consumer information, such as itinerary choice modeling. We developed a software package called Larch, written in Python and C++, to take advantage of this kind of data to greatly speed the estimation of discrete choice model parameters. Benchmarking experiments against Stata (a commonly used commercial package) and Biogeme (a commonly used freeware package) based on an industry dataset for airline itinerary choice modeling applications shows that the size of the input estimation files are 50 to 100 times larger in Stata and Biogeme, respectively. Estimation times are also much faster in Larch; e.g., for a small itinerary choice problem, a multinomial logit model estimated in Larch converged in less than one second whereas the same model took almost 15 seconds in Stata and more than three minutes in Biogeme. For more complex discrete choice models, such as the ordered generalized extreme value model, estimation times were two seconds in Larch and four to five days in Biogeme. [less ▲]

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See detailTHE BEAT GENERATION Beat Generation - L’Anthologie Musicale - Hep Cats, Hipsters & Beatniks 1936-1962 (FREMEAUX & ASSOCIES)
Sacré, Robert ULg

E-print/Working paper (2016)

The Beat Generation - L’Anthologie Musicale - Compte rendu Hep Cats, Hipsters & Beatniks 1936-1962 FREMEAUX & ASSOCIES

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See detailBIG NOISE - Un orchestre belge- Un nouvel hommage, en live, au JAZZ style NEW ORLEANS
Sacré, Robert ULg

E-print/Working paper (2016)

Compte Rendu du 3è opus du groupe BIG NOISE, un orchestre belge qui remet à l'honneur le jazz traditionnel style NEW ORLEANS ( album IGLOO RECORDS)

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See detailThe np- Control Charts with the Guaranteed In-Control Performance
Faraz, Alireza ULg; Heuchenne, Cédric ULg

E-print/Working paper (2016)

In this paper, we evaluate the in-control performance of np-control charts with estimated parameters. We then apply the bootstrap method to adjust the control charts’ limits to guarantee the desired in ... [more ▼]

In this paper, we evaluate the in-control performance of np-control charts with estimated parameters. We then apply the bootstrap method to adjust the control charts’ limits to guarantee the desired in-control average run length (ARL0) value in monitoring stage. The adjusted limits ensure that ARL0 would take a value greater than the desired value (say, B) with a certain specified probability, that is Pr⁡(ARL_0>B)=1-ρ. We finally provide users with tables which with practitioners do not need to do bootstrapping Phase I data set to obtain the control limit thresholds. [less ▲]

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See detailWASP-92b, WASP-93b and WASP-118b: Three new transiting close-in giant planets
Hay, K. L.; Collier-Cameron, A.; Doyle, A. P. et al

E-print/Working paper (2016)

We present the discovery of three new transiting giant planets, first detected with the WASP telescopes, and establish their planetary nature with follow up spectroscopy and ground-based photometric ... [more ▼]

We present the discovery of three new transiting giant planets, first detected with the WASP telescopes, and establish their planetary nature with follow up spectroscopy and ground-based photometric lightcurves. WASP-92 is an F7 star, with a moderately inflated planet orbiting with a period of 2.17 days, which has R[SUB]p[/SUB] = 1.461 ± 0.077R[SUB]J[/SUB] and M[SUB]p[/SUB] = 0.805 ± 0.068M[SUB]J[/SUB]. WASP-93b orbits its F4 host star every 2.73 days and has R[SUB]p[/SUB] = 1.597 ± 0.077R[SUB]J[/SUB] and M[SUB]p[/SUB] = 1.47 ± 0.029M[SUB]J[/SUB]. WASP-118b also has a hot host star (F6) and is moderately inflated, where R[SUB]p[/SUB] = 1.440 ± 0.036R[SUB]J[/SUB] and M[SUB]p[/SUB] = 0.514 ± 0.020M[SUB]J[/SUB] and the planet has an orbital period of 4.05 days. They are bright targets (V = 13.18, 10.97 and 11.07 respectively) ideal for further characterisation work, particularly WASP-118b, which is being observed by K2 as part of campaign 8. The WASP-93 system has sufficient angular momentum to be tidally migrating outwards if the system is near spin-orbit alignment, which is divergent from the tidal behaviour of the majority of hot Jupiters discovered. [less ▲]

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See detailThe Economic Forces Behind Deindustrialization: An Empirical Investigation
Van Neuss, Leif ULg

E-print/Working paper (2016)

The purpose of this paper is to provide an in-depth study of deindustrialization and to systematically analyze the reasons why the world’s most economically successful countries have experienced a sharp ... [more ▼]

The purpose of this paper is to provide an in-depth study of deindustrialization and to systematically analyze the reasons why the world’s most economically successful countries have experienced a sharp decline in relative manufacturing employment over the last decades. A large strand of empirical literature on deindustrialization aims at quantifying the relative importance of the economic forces behind deindustrialization, especially of the ‘internal’ and ‘external’ factors. While this study does not contradict the widespread belief that internal factors are quantitatively more important in explaining deindustrialization in advanced countries taken as a whole, our results, based on both static and dynamic techniques and panel data on 18 OECD countries from 1977 to 2007, however suggest that the role of globalization may be revised upwards when resorting to appropriate and well-defined indicators of trade in manufactures. [less ▲]

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See detailThey will need land! The current land tenure situation and future land allocation needs of smallholder farmers in Cambodia
Diepart, Jean-Christophe ULg

E-print/Working paper (2016)

The objective of this background paper is to provide a succinct description of the land tenure situation in Cambodia and, on that basis, discuss the needs smallholder farmers have for land, projected up ... [more ▼]

The objective of this background paper is to provide a succinct description of the land tenure situation in Cambodia and, on that basis, discuss the needs smallholder farmers have for land, projected up to the year 2030. The main problem it examines lies at the intersection between, on one hand, the demographic increase in the rural smallholder population and its associated need for land in the future (the demand side) and, on the other hand, the possibility offered by the different land tenure regimes to meet this demand (the supply side); the central question focuses on how supply can meet demand.By looking first at how much land is available under different categories (the supply side), the paper succinctly presents and maps the different land tenure regimes with updated statistics and discusses their main outcomes and shortcomings. On that basis, we present a preliminary assessment of land distribution by main land tenure systems in Cambodia. The land under cultivation by smallholders represents 19 percent of the total area of the national territory and is itself sub-divided into agricultural land with land titles (systematic land registration, 6 percent and land covered by the Order 01, 6 percent), under Social Land Concession arrangements (1 percent) and untitled (6 percent). The forest cover includes forest concessions (10 percent), Community Forestry (2 percent), Protected Areas and Protection Forests (20 percent) and an unclassified forest cover area (14 percent). Economic Land Concessions under operation represent 12 percent while cancelled concessions represent 2 percent of the total territory. The actual tenure of a large non-forested area (14 percent) remains undetermined and further updates are needed to shed light on this issue. The paper suggests that the central problem of the current Cambodian land reform is its ineffectiveness in coordinating the processes of land rights security and formalization in lowland and upland areas, although both regions are closely linked through land-driven migration movements that have intensified over the past 20 years. This has been particularly contentious given the fact that in a parallel process, and driven by a strong, state-based political economy, large land deals have been concentrated in the uplands of the entire country along processes that are exclusionary in nature. The overlap of competing land claims has created a widespread conflict situation in all uplands region of the country. By looking at how much land is needed for family farmers in the future (the demand side), the paper anticipates the land requirements of smallholder farmers by 2030 based on the projected demographic increase in the economically active population in rural Cambodia and on two sets of scenarios i) the transfer of unskilled labour from the agricultural to the secondary and tertiary sectors (industries and services) and ii) the provision of land for smallholder farmers. The analysis suggests that by the year 2030, the transfer of unskilled labour from agriculture to the secondary and tertiary sectors will lag behind the demographic increase in the active rural population. With 2015 as a baseline, the scenarios suggests that by 2030 smallholder farmers will need an additional land area ranging from 320,600 ha (+10 percent in relation to the actual area at the present time) to 1,962,400 (+64 percent), with an average desirable scenario of 1,622.000 ha based on an allocation of 1ha per active labourer (in accordance with the present social concession policy) and on the continuation of the present transfer rate of unskilled manpower from agriculture to the secondary and tertiary sectors (i.e. the transfer of 40.000 workers per year). So the question that needs to be formulated does not revolve around whether or not the rural population will need land in the future, but rather around how this can occur. Along these lines, the paper discusses different options, which are not mutually exclusive, to allocate this land without further impact on the forest cover: i) by redistribution of land from cancelled Economic Land Concessions, ii) through a firmer recognition of swidden agriculture inside Protected Areas, iii) through a far more ambitious Social Land Concession programme and iv) through further reform of the forest concession system. The paper concludes by stressing the need for relevant ministries to engage in open and constructive research-based discussion so that these options can materialize into concrete actions. [less ▲]

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See detailThymectomy in myasthenia gravis: removal of the defective 'sick' organ?
Geenen, Vincent ULg

E-print/Working paper (2016)

As evidenced by this randomized trial, thymectomy clearly improved clinical status of patients with nonthymomatous myasthenia gravis (MG) and this study ends a very long controversy about the interest of ... [more ▼]

As evidenced by this randomized trial, thymectomy clearly improved clinical status of patients with nonthymomatous myasthenia gravis (MG) and this study ends a very long controversy about the interest of this surgical procedure mainly based on previous empirical observations. Although they are not discussed in this important paper, a series of experimental arguments reviewed in joint references argue for the idea that the clinical benefit of thymectomy is primarily due to the removal of the organ primarily implicated in MG pathophysiology. The thymus plays a central role in programming central immunological self-tolerance [1,2], and a thymus dysfunction is a primary event in the development of organ-specific autoimmunity [3,4]. It is therefore not surprising that the surgical removal of the primary 'sick' organ contributes to improve clinical outcomes and to reduce immunosuppressive therapy in MG patients. References: 1. Kamradt T, Mitchison NA. N Engl J Med 2001; 344:655-64. 2. Kyewski B, Klein L. Annu Rev Immunol 2006; 24:571-606. 3. Giraud M, Taubert R, Vandiedonck C, et al. Nature 2007; 448:934-7. 4. Geenen V, Bodart G, Henry S, et al. Front Neurosc 2013; 7:art 187. [less ▲]

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See detailMany-Body Spin Echo
Engl, Thomas; Urbina, Juan Diego; Richter, Klaus et al

E-print/Working paper (2016)

We predict a universal echo phenomenon present in the time evolution of many-body states of interacting quantum systems described by Fermi-Hubbard models. It consists of the coherent revival of transition ... [more ▼]

We predict a universal echo phenomenon present in the time evolution of many-body states of interacting quantum systems described by Fermi-Hubbard models. It consists of the coherent revival of transition probabilities echoing a sudden flip of the spins that, contrary to its single-particle (Hahn) version, is not dephased by interactions or spin-orbit coupling. The many-body spin echo signal has a universal shape independent of the interaction strength, and an amplitude and sign depending only on combinatorial relations between the number of particles and the number of applied spin flips. Our analytical predictions, based on semiclassical interfering amplitudes in Fock space associated with chaotic mean-field solutions, are tested against extensive numerical simulations confirming that the coherent origin of the echo lies in the existence of anti-unitary symmetries. [less ▲]

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See detailDiscovery of WASP-113b and WASP-114b, two inflated hot-Jupiters with contrasting densities
Barros, S. C. C.; Brown, D. J. A.; Hébrard, G. et al

E-print/Working paper (2016)

We present the discovery and characterisation of the exoplanets WASP-113b and WASP-114b by the WASP survey, {\it SOPHIE} and {\it CORALIE}. The planetary nature of the systems was established by ... [more ▼]

We present the discovery and characterisation of the exoplanets WASP-113b and WASP-114b by the WASP survey, {\it SOPHIE} and {\it CORALIE}. The planetary nature of the systems was established by performing follow-up photometric and spectroscopic observations. The follow-up data were combined with the WASP-photometry and analysed with an MCMC code to obtain system parameters. The host stars WASP-113 and WASP-114 are very similar. They are both early G-type stars with an effective temperature of $\sim 5900\,$K, [Fe/H]$\sim 0.12$ and $T_{\rm eff}$ $\sim 4.1$dex. However, WASP-113 is older than WASP-114. Although the planetary companions have similar radii, WASP-114b is almost 4 times heavier than WASP-113b. WASP-113b has a mass of $0.48\,$ $\mathrm{M}_{\rm Jup}$ and an orbital period of $\sim 4.5\,$days; WASP-114b has a mass of $1.77\,$ $\mathrm{M}_{\rm Jup}$ and an orbital period of $\sim 1.5\,$days. Both planets have inflated radii, in particular WASP-113 with a radius anomaly of $\Re=0.35$. The high scale height of WASP-113b ($\sim 950$ km ) makes it a good target for follow-up atmospheric observations. [less ▲]

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See detailFrom Dense Hot Jupiter to Low Density Neptune: The Discovery of WASP-127b, WASP-136b and WASP-138b
Lam, K. W. F.; Faedi, F.; Brown, D. J. A. et al

E-print/Working paper (2016)

We report three newly discovered exoplanets from the SuperWASP survey. WASP-127b is a heavily inflated super-Neptune of mass 0.18Mj and radius 1.35Rj. This is one of the least massive planets discovered ... [more ▼]

We report three newly discovered exoplanets from the SuperWASP survey. WASP-127b is a heavily inflated super-Neptune of mass 0.18Mj and radius 1.35Rj. This is one of the least massive planets discovered by the WASP project. It orbits a bright host star (V = 10.16) of spectral type G5 with a period of 4.17 days.WASP-127b is a low density planet which has an extended atmosphere with a scale height of 2500+/-400 km, making it an ideal candidate for transmission spectroscopy. WASP-136b and WASP-138b are both hot Jupiters with mass and radii of 1.51 Mj and 1.38 Rj, and 1.22 Mj and 1.09 Rj, respectively. WASP-136b is in a 5.22-day orbit around an F9 subgiant star with a mass of 1.41 Msun and a radius of 2.21 Rsun. The discovery of WASP-136b could help constraint the characteristics of the giant planet population around evolved stars. WASP-138b orbits an F7 star with a period of 3.63 days. Its radius agrees with theoretical values from standard models, suggesting the presence of a heavy element core with a mass of 10 Mearth. The discovery of these new planets helps in exploring the diverse compositional range of short-period planets, and will aid our understanding of the physical characteristics of both gas giants and low density planets. [less ▲]

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See detailWaveguides for walking droplets
Filoux, Boris ULg; Hubert, Maxime ULg; Schlagheck, Peter ULg et al

E-print/Working paper (2016)

When gently placing a droplet onto a vertically vibrated bath, a drop can bounce without coalescing. Upon increasing the forcing acceleration, the droplet is propelled by the wave it generates and becomes ... [more ▼]

When gently placing a droplet onto a vertically vibrated bath, a drop can bounce without coalescing. Upon increasing the forcing acceleration, the droplet is propelled by the wave it generates and becomes a walker with a well defined speed. We investigate the confinement of a walker in different rectangular cavities, used as waveguides for the Faraday waves emitted by successive droplet bounces. By studying the walker velocities, we discover that 1d confinement is optimal for narrow channels of width of D≃1.5λF. We also propose an analogy with waveguide models based on the observation of the Faraday instability within the channels. [less ▲]

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See detailNouvelles normes sylvicoles pour les peuplements purs équiennes d'épicéa et de douglas
Perin, Jérôme ULg; Hebert, Jacques ULg; Lejeune, Philippe ULg et al

E-print/Working paper (2016)

Ces documents rassemblent les tables de production (version 2016) représentant les nouvelles normes sylvicoles recommandées pour les peuplements purs équiennes d'épicéa commun et de douglas. Un ensemble ... [more ▼]

Ces documents rassemblent les tables de production (version 2016) représentant les nouvelles normes sylvicoles recommandées pour les peuplements purs équiennes d'épicéa commun et de douglas. Un ensemble de 10 tables de production est présentée pour chaque essence, associant deux densités de plantation (2.5 x 2 m et 2 x 2 m) et 5 classes de productivité (0 à IV). [less ▲]

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See detailLars Gustafsson, Strindberg et l'ordinateur [critique]
Dupont, Bruno ULg

E-print/Working paper (2016)

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See detailStein's method, many interacting worlds and quantum mechanics
McKeague, Ian; Peköz, Erol; Swan, Yvik ULg

E-print/Working paper (2016)

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See detailA class of valid inequalities for multilinear 0-1 optimization problems
Crama, Yves ULg; Rodriguez Heck, Elisabeth ULg

E-print/Working paper (2016)

This paper investigates the polytope associated with the classical standard linearization technique for the unconstrained optimization of multilinear polynomials in 0-1 variables. A new class of valid ... [more ▼]

This paper investigates the polytope associated with the classical standard linearization technique for the unconstrained optimization of multilinear polynomials in 0-1 variables. A new class of valid inequalities, called 2-links, is introduced to strengthen the LP relaxation of the standard linearization. The addition of the 2-links to the standard linearization inequalities provides a complete description of the convex hull of integer solutions for the case of functions consisting of at most two nonlinear monomials. For the general case, various computational experiments show that the 2- links improve both the standard linearization bound and the computational performance of exact branch & cut methods. The improvements are especially significant for a class of instances inspired from the image restoration problem in computer vision. The magnitude of this effect is rather surprising in that the 2-links are in relatively small number (quadratic in the number of terms of the objective function). [less ▲]

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See detailScattering theory of walking droplets in the presence of obstacles
Dubertrand, Rémy ULg; Hubert, Maxime ULg; Schlagheck, Peter ULg et al

E-print/Working paper (2016)

We aim to describe a droplet bouncing on a vibrating bath. Due to Faraday instability a surface wave is created at each bounce and serves as a pilot wave of the droplet. This leads to so called walking ... [more ▼]

We aim to describe a droplet bouncing on a vibrating bath. Due to Faraday instability a surface wave is created at each bounce and serves as a pilot wave of the droplet. This leads to so called walking droplets or walkers. Since the seminal experiment by {\it Couder et al} [Phys. Rev. Lett. {\bf 97}, 154101 (2006)] there have been many attempts to accurately reproduce the experimental results. Here we present a simple and highly versatile model inspired from quantum mechanics. We propose to describe the trajectories of a walker using a Green function approach. The Green function is related to Helmholtz equation with Neumann boundary conditions on the obstacle(s) and outgoing conditions at infinity. For a single slit geometry our model is exactly solvable and reproduces some general features observed experimentally. It stands for a promising candidate to account for the presence of any boundaries in the walkers'dynamics. [less ▲]

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See detailEarly Detection of University Students in Potential Difficulty
Hoffait, Anne-Sophie ULg; Schyns, Michael ULg

E-print/Working paper (2016)

Using data mining methods, this paper presents a new means of identifying freshmen's profiles likely to face major difficulties to complete their first academic year. Academic failure is a relevant issue ... [more ▼]

Using data mining methods, this paper presents a new means of identifying freshmen's profiles likely to face major difficulties to complete their first academic year. Academic failure is a relevant issue at a time when post-secondary education is ever more critical to economic success. We aim at early detection of potential failure using student data available at registration, i.e. school records and environmental factors, with a view to timely and efficient remediation and/or study reorientation. For the sake of accuracy, we adapt three data mining methods, namely random forest, logistic regression and artificial neural network algorithms. Real data pertaining to undergraduates at the University of Liège (Belgium), illustrates our methodology. [less ▲]

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See detailDistances between probability distributions via characteristic functions and biasing
Azmoodeh, Ehsan; Arras, Benjamin; Poly, Guillaume et al

E-print/Working paper (2016)

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See detailStein operators for product distributions, with applications
Mijoule, Guillaume; Gaunt, Robert; Swan, Yvik ULg

E-print/Working paper (2016)

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See detailAppropriability and the European Commission’s Android Investigation
Auer, Dirk ULg

E-print/Working paper (2016)

This paper seeks to ascertain whether Google’s Android licensing terms, which are currently under scrutiny from the European Commission, could be excused under an innovation defense framework. The paper ... [more ▼]

This paper seeks to ascertain whether Google’s Android licensing terms, which are currently under scrutiny from the European Commission, could be excused under an innovation defense framework. The paper starts by analyzing Google’s business model with regard to its Android OS. It then identifies the Commission’s main concerns. It argues that Google is simply pursuing a sensible appropriation strategy. Finally, it puts forward a framework which hinges on the concept of “appropriability”, and tentatively applies it to Google’s behavior. [less ▲]

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See detailWASP-South transiting exoplanets: WASP-130b, WASP-131b, WASP-132b, WASP-139b, WASP-140b, WASP-141b & WASP-142b
Hellier, Coel; Anderson, D. R.; Collier Cameron, A. et al

E-print/Working paper (2016)

We describe seven new exoplanets transiting stars of V = 10.1 to 12.4. WASP-130b is a "warm Jupiter" having an orbital period of 11.6 d, the longest yet found by WASP. It transits a V = 11.1, G6 star with ... [more ▼]

We describe seven new exoplanets transiting stars of V = 10.1 to 12.4. WASP-130b is a "warm Jupiter" having an orbital period of 11.6 d, the longest yet found by WASP. It transits a V = 11.1, G6 star with [Fe/H] = +0.26. Warm Jupiters tend to have smaller radii than hot Jupiters, and WASP-130b is in line with this trend (1.23 Mjup; 0.89 Rjup). WASP-131b is a bloated Saturn-mass planet (0.27 Mjup; 1.22 Rjup). Its large scale height coupled with the V = 10.1 brightness of its host star make the planet a good target for atmospheric characterisation. WASP-132b is among the least irradiated and coolest of WASP planets, being in a 7.1-d orbit around a K4 star. It has a low mass and a modest radius (0.41 Mjup; 0.87 Rjup). The V = 12.4, [Fe/H] = +0.22 star shows a possible rotational modulation at 33 d. WASP-139b is the lowest-mass planet yet found by WASP, at 0.12 Mjup and 0.80 Rjup. It is a "super-Neptune" akin to HATS-7b and HATS-8b. It orbits a V = 12.4, [Fe/H] = +0.20, K0 star. The star appears to be anomalously dense, akin to HAT-P-11. WASP-140b is a 2.4-Mjup planet in a 2.2-d orbit that is both eccentric (e = 0.047) and with a grazing transit (b = 0.93) The timescale for tidal circularisation is likely to be the lowest of all known eccentric hot Jupiters. The planet's radius is large (1.4 Rjup), but uncertain owing to the grazing transit. The host star is a V = 11.1, [Fe/H] = +0.12, K0 dwarf showing a prominent 10.4-d rotational modulation. The dynamics of this system are worthy of further investigation. WASP-141b is a typical hot Jupiter, being a 2.7 Mjup, 1.2 Rjup planet in a 3.3-d orbit around a V = 12.4, [Fe/H] = +0.29, F9 star. WASP-142b is a typical bloated hot Jupiter (0.84 Mjup, 1.53 Rjup) in a 2.1-d orbit around a V = 12.3, [Fe/H] = +0.26, F8 star. [less ▲]

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See detailSuccess SMB:Leadership Andr Multidimensional Management. An exploratoire Study.
Robert, Jocelyne ULg

E-print/Working paper (2016)

Montre l'importance du leadership comme facteur de succès des PME en croissance rapide (gazelles ). Étude exploratoire.

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See detailStein's method on the second Wiener chaos : 2-Wasserstein distance
Arras, Benjamin; Mijoule, Guillaume; Poly, Guillaume et al

E-print/Working paper (2016)

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See detailPublic Education Expenditures, Growth and Income Inequality
Artige, Lionel ULg; Cavenaile, Laurent

E-print/Working paper (2016)

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See detailLe législateur wallon sommé de revoir le découpage des circonscriptions électorales
Bouhon, Frédéric ULg

E-print/Working paper (2016)

Le caractère proportionnel de notre système électoral n’est pas un vain mot et ne peut être contourné. C’est ce que viennent de rappeler deux arrêts, le premier, prononcé par le Conseil d’État, datant du ... [more ▼]

Le caractère proportionnel de notre système électoral n’est pas un vain mot et ne peut être contourné. C’est ce que viennent de rappeler deux arrêts, le premier, prononcé par le Conseil d’État, datant du 20 novembre 2014 (n° 229.252) , le second, rendu par la Cour constitutionnelle le 26 novembre 2015 (n° 169/2015) . Le Parlement wallon doit revoir la carte électorale en vue des prochaines élections. [less ▲]

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See detailRevealing the role of network rigidity on the fragility evolution of glass-forming liquids
Yildirim, Can ULg; Raty, Jean-Yves ULg; Micoulaut, Mathieu

E-print/Working paper (2016)

If quenched fast enough, a liquid is able to avoid crystallization and will remain in a metastable supercooled state down to the glass transition, with an important increase in viscosity and relaxation ... [more ▼]

If quenched fast enough, a liquid is able to avoid crystallization and will remain in a metastable supercooled state down to the glass transition, with an important increase in viscosity and relaxation time towards equilibrium upon further cooling [1,2]. There are important differences in the way liquids relax as they approach the glass transition, rapid or slow variation in dynamic quantities under moderate temperature changes, and a simple means to quantify such variations is provided by the concept of "fragility". Here, we report molecular dynamics simulations of a typical network-forming glass, and find that the relaxation behaviour of the supercooled liquid is strongly correlated to the variation of rigidity with temperature and the spatial distribution of the corresponding topological constraints which, ultimately connect to fragility minima . This permits extending the fragility concept to aspects of topology/rigidity, and to the degree of homogeneity of the atomic-sale interactions for a variety of structural glasses. [less ▲]

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See detailCore Content Classification in General Practice Family medicine (3CGP) The Q-Codes user guide
Jamoulle, Marc ULg

E-print/Working paper (2016)

user guide and general explanation pages for the Q-codes, a classification of managerial issues in General Practice / Family Medicine

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See detailL’aménagement forestier au Congo engendre-t-il plus de déforestation ?
Karsenty, Alain; Cerutti, P.; Doucet, Jean-Louis ULg et al

E-print/Working paper (2016)

Un article publié dans Land Use Policy début 2016 arrive à la conclusion a priori étonnante que la déforestation serait, au Congo, plus élevée dans les concessions forestières avec des plans d’aménagement ... [more ▼]

Un article publié dans Land Use Policy début 2016 arrive à la conclusion a priori étonnante que la déforestation serait, au Congo, plus élevée dans les concessions forestières avec des plans d’aménagement que dans celles qui n’en ont pas. L’analyse d’évaluation d’impact qui a conduit ces chercheurs à un tel résultat se base sur un appariement de parcelles sélectionnées aléatoirement dans des concessions avec et sans plans d’aménagement. Ces chercheurs indiquent que le réseau de routes forestières plus développé dans les concessions aménagées serait un des facteurs explicatifs. L’autre facteur serait le développement local lié aux cahiers des charges des plans d’aménagement, lequel conduirait à une augmentation de la population dans ces concessions et à une déforestation accrue. Notre groupe d’une vingtaine de chercheurs connaissant bien la problématique de l’aménagement forestier en Afrique centrale s’est penché à son tour sur cette question et a analysé la déforestation au niveau des concessions sur le même intervalle de temps. Nos résultats montrent, cette fois, que la déforestation est moins importante dans les concessions avec un plan d’aménagement que dans les autres. Et si l’on compare à production égale la déforestation dans des concessions avec et sans plan d’aménagement, il apparaît que les UFA aménagées sont environ deux fois plus « efficaces », c’est-à-dire qu’on observe deux fois moins de perte de couvert forestier par mètre-cube produit. Nous en concluons qu’il est nécessaire d’analyser précisément la dynamique des différents facteurs de déforestation, et éviter d’imputer mécaniquement à l’aménagement forestier un rôle excessif dans l’évolution dans un sens ou dans l’autre du taux de déboisement. Enfin, toute évaluation doit rappeler que les effets de l’aménagement forestier doivent être mesurés sur le long terme : l’objectif de l’aménagement est de permettre une mise en valeur forestière durable, en conservant l’essentiel du capital productif pour éviter, autant que possible, la conversion à d’autres usages après les cycles de coupe initiaux. [less ▲]

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See detailFive years on for Fukushima's IDPs: Life with radiological risk and without a community safety net
Hasegawa, Reiko ULg

E-print/Working paper (2016)

On the fifth anniversary of the Fukushima nuclear accident, the article analyses what are at stake in the communities affected by the disaster, based on the result of the field interviews conducted in ... [more ▼]

On the fifth anniversary of the Fukushima nuclear accident, the article analyses what are at stake in the communities affected by the disaster, based on the result of the field interviews conducted in Fukushima. [less ▲]

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See detailWASP-157b, a Transiting Hot Jupiter Observed with K2
Močnik, T.; Anderson, D. R.; Brown, D. J. A. et al

E-print/Working paper (2016)

We announce the discovery of the transiting hot Jupiter WASP-157b in a 3.95-d orbit around a V = 12.9 G2 main-sequence star. This moderately inflated planet has a Saturn-like density with a mass of $0.57 ... [more ▼]

We announce the discovery of the transiting hot Jupiter WASP-157b in a 3.95-d orbit around a V = 12.9 G2 main-sequence star. This moderately inflated planet has a Saturn-like density with a mass of $0.57 \pm 0.10$ M$_{\rm Jup}$ and a radius of $1.06 \pm 0.05$ R$_{\rm Jup}$. We do not detect any rotational or phase-curve modulations, nor the secondary eclipse, with conservative semi-amplitude upper limits of 250 and 20 ppm, respectively. [less ▲]

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See detailSouthern Blues Night , Heerlen (Hollande) 19 mars 2016
Sacré, Robert ULg

E-print/Working paper (2016)

Compte rendu de la Southern Blues Night annuelle de Heerlen aux Pays Bas, avec photos

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See detailNote on the numerical solution of the scalar Helmholtz equation in a nanotorus with uniform Dirichlet boundary conditions
Nguyen, Ngoc Duy ULg; Evrard, Roger ULg; Stroscio, Michael

E-print/Working paper (2016)

This note describes the solution of the Helmholtz equation inside a nanotorus with uniform Dirichlet boundary conditions. The eigenfunction symmetry is discussed and the lower-order eigenvalues and ... [more ▼]

This note describes the solution of the Helmholtz equation inside a nanotorus with uniform Dirichlet boundary conditions. The eigenfunction symmetry is discussed and the lower-order eigenvalues and eigenfunctions are shown. The similarity with the case of a long cylinder and with that of the vibrations of a circular elastic membrane is discussed. This similarity is used to propose a classification scheme of the eigenfunctions based on three indices. [less ▲]

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See detailThe Smallest Salable Patent-Practicing Unit ('SSPPU') Experiment, General Purpose Technologies and the Coase Theorem
Petit, Nicolas ULg

E-print/Working paper (2016)

In the last years, some Standard-Setting Organizations (“SSOs”) active in wireless communications have experimented new pricing principles for standard essential patents (“SEPs”). One of those experiments ... [more ▼]

In the last years, some Standard-Setting Organizations (“SSOs”) active in wireless communications have experimented new pricing principles for standard essential patents (“SEPs”). One of those experiments is the “SSPPU” rule. Under SSPPU, the licensing rates paid to owners of SEPs for the use of their technology shall reflect the “value that the functionality of the claimed invention or inventive feature…contributes to the value of the relevant functionality of the smallest saleable Compliant Implementation that practices the Essential Patent Claim”. This paper reviews the SSPPU experiment through the lenses of the Coase theorem. It finds that SSPPU interferes with the efficient operation of the price system, and is likely to reduce investment in socially beneficial activities, including in General Purpose Technologies (“GPTs”) which are key drivers of economic growth. [less ▲]

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See detailLa diversité des expressions culturelles au tourbillon du numérique
Vlassis, Antonios ULg

E-print/Working paper (2016)

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See detailSome characterizations about Generalized Hölder-Zygmund Spaces Λ_{σ,N}^{α}(R^d)
Kreit, Damien ULg; Nicolay, Samuel ULg

E-print/Working paper (2016)

Generalized Hölder-Zygmund spaces $\Lambda_{\sigma, N}^{\alpha}(\R^{d})$ were recently introduced and are based on a generalization of Besov spaces. Under some conditions, generalized Hölder-Zygmund and ... [more ▼]

Generalized Hölder-Zygmund spaces $\Lambda_{\sigma, N}^{\alpha}(\R^{d})$ were recently introduced and are based on a generalization of Besov spaces. Under some conditions, generalized Hölder-Zygmund and Besov spaces are equal. It has been proved that most properties of classical Hölder-Zygmund spaces are held for spaces $\Lambda^{\sigma,\alpha}(\R^{d})$, which constitute a particular case of spaces $\Lambda_{\sigma, N}^{\alpha}(\R^{d})$ with $N_{j}=2^{j}$. The goal of the present document is to prove that most of these properties are kept for $\Lambda_{\sigma, N}^{\alpha}(\R^{d})$ spaces. [less ▲]

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See detailA Comparison of Departure Time of Day Formulations
Lurkin, Virginie ULg; Garrow, Laurie; Higgins, Matthew et al

E-print/Working paper (2016)

Airline passengers’ itinerary choices are influenced by many factors including carriers, prices, the number of connections, and departure times. This paper compares three different methods that have been ... [more ▼]

Airline passengers’ itinerary choices are influenced by many factors including carriers, prices, the number of connections, and departure times. This paper compares three different methods that have been used to model departure time of day preferences. The first is a discrete formulation that uses indicator variables to represent the hour of departure. The next two methods are based on a continuous formulation that uses a series of sine and cosine functions. One assumes departure time preferences over a 24-hour cycle and the other uses shorter cycle lengths that account for fewer departures during certain hours of the day. We compare models using itineraries in the Continental U.S. that are separated by two time zones. Although the discrete formulation fits the data better, the two continuous time of day formulations are preferred as they provide more intuitive predictions and require fewer parameters. Results between the two continuous time of day formulations are similar but differ in how strongly they weight itineraries that depart very early or very late in the day. Based on empirical results, we recommend testing both 24-hour and less than 24-hour cycle lengths for a particular dataset. [less ▲]

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See detailContinuous Departure Time of Day Preferences for Continental U.S. Airline Markets Segmented by Distance, Direction of Travel, Number of Time Zones, Day of Week and Itinerary Type
Lurkin, Virginie ULg; Garrow, Laurie; Higgins, Matthew et al

E-print/Working paper (2016)

Airlines use itinerary choice models to allocate the total number of passengers in a city pair to specific itineraries. In a related paper, we estimated a multinomial logit (MNL) itinerary choice model ... [more ▼]

Airlines use itinerary choice models to allocate the total number of passengers in a city pair to specific itineraries. In a related paper, we estimated a multinomial logit (MNL) itinerary choice model using database of more than 3 million tickets for Continental U.S. markets provided by the Airlines Reporting Corporation that accounted for price endogeneity. The size and comprehensiveness of our database allowed us to estimate highly refined continuous departure time of day preference curves that account for distance, direction of travel, the number of time zones traversed, departure day of week and itinerary type (outbound, inbound or one-way). This paper and accompanying Excel spreadsheet located at http://garrowlab.ce.gatech.edu contain the results of all model coefficients (including the 1260 time of day parameters) and summarize results in a series of ten figures. These highly-refined time of day preference curves can be used by airlines, researchers, and government organizations in the evaluation of demand-management and other policies. [less ▲]

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See detailAccounting for Price Endogeneity in Airline Itinerary Choice Models: An Application to Continental U.S. Markets
Lurkin, Virginie ULg; Garrow, Laurie; Higgins, Matthew et al

E-print/Working paper (2016)

Network planning models, which forecast the profitability of airline schedules, support many critical decisions, including equipment purchase decisions. Network planning models include an itinerary choice ... [more ▼]

Network planning models, which forecast the profitability of airline schedules, support many critical decisions, including equipment purchase decisions. Network planning models include an itinerary choice model which is used to allocate air total demand in a city pair to different itineraries. Multinomial logit (MNL) models are commonly used in practice and capture how individuals make trade-offs among different itinerary attributes; however, none that we are aware of account for price endogeneity. This study formulates an itinerary choice model that is consistent with those used by industry and corrects for price endogeneity using a control function that uses several types of instrumental variables. We estimate our models using database of more than 3 million tickets provided by the Airlines Reporting Corporation. Results based on Continental U.S. markets for May 2013 departures show that models that fail to account for price endogeneity overestimate customers’ value of time and result in biased price estimates and incorrect pricing recommendations. The size and comprehensiveness of our database allows us to estimate highly refined departure time of day preference curves that account for distance, direction of travel, the number of time zones traversed, departure day of week and itinerary type (outbound, inbound or one-way). These time of day preference curves can be used by airlines, researchers, and government organizations in the evaluation of different policies such as congestion pricing. [less ▲]

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See detailPolitique de la Ville : Dynamisation des coeurs de ville
Bastin, Florine ULg; Lacroix, Gilles; May, Xavier et al

E-print/Working paper (2016)

La régionalisation de la Politique Fédérale des Grandes Villes, suite à la sixième réforme de l’Etat, fut une opportunité de s’interroger sur les objectifs et l’organisation d’une Politique de la Ville en ... [more ▼]

La régionalisation de la Politique Fédérale des Grandes Villes, suite à la sixième réforme de l’Etat, fut une opportunité de s’interroger sur les objectifs et l’organisation d’une Politique de la Ville en Wallonie. Dans ce cadre, la note de recherche CPDT n°63 « Politique de la ville. Dynamisation des cœurs de ville » répond à la volonté du Gouvernement wallon de se doter d’une vision territoriale stratégique sur le long terme et est un premier pas vers la mise en place d’une politique de la ville intégrée en Wallonie. Cette note fait le point sur, d’une part, les différentes politiques et outils relatifs à la restructuration et à la dynamisation des tissus urbains, au sens large, établis au niveau régional, fédéral et européen et, d’autre part, les propositions et recommandations relatives à l’évolution du cadre actuel. Cette réflexion s’adresse évidemment aux acteurs concernés par les enjeux de gouvernance urbaine : les décideurs politiques, les villes et les communes mais concerne aussi le citoyen. [less ▲]

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See detailStructure et négativité dans la Préface de 1961 à L'Histoire de la folie
Oulc'hen, Hervé ULg

E-print/Working paper (2016)

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See detailHistoires de rayons verts : phénomène physique, critique de cinéma, spectateurs mélancoliques
Barbion, Sébastien ULg

E-print/Working paper (2016)

En s’appuyant sur la physique, un roman de Jules Verne et un film de Rohmer, ce texte déplie les différents aspects théoriques et pratiques contenus dans le concept de rayon vert : un type de perception ... [more ▼]

En s’appuyant sur la physique, un roman de Jules Verne et un film de Rohmer, ce texte déplie les différents aspects théoriques et pratiques contenus dans le concept de rayon vert : un type de perception, une manière de concevoir la critique de cinéma, une expérience de spectateur. [less ▲]

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See detailOlder men’s labor force participation in Belgium
Jousten, Alain ULg; Lefebvre, Mathieu ULg

E-print/Working paper (2016)

We provide an overview of the institutional framework in Belgium that is of relevance for labor market participation and retirement decision at older ages. We then describe key labor market indicators ... [more ▼]

We provide an overview of the institutional framework in Belgium that is of relevance for labor market participation and retirement decision at older ages. We then describe key labor market indicators using data from the Labour Force Survey (LFS) over the period 1983-2013 and also present trends in participation in (early-) retirement routes. Next, we explore how the types of jobs in the country have changed over time, both in terms of their “quality” and the “quantity” of work involved. [less ▲]

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See detailRésumé de la thèse: Rôle du climat et de la compétition interspécifique dans la limitation de l'aire d'invasion d'Ambrosia artemisiifolia L. en Europe de l'Ouest
Ortmans, William ULg

E-print/Working paper (2016)

The invasion continuum is classically described from a temporal point of view, where a species overcomes a defined number of barriers linked to the environment. First, an exotic species has to get through ... [more ▼]

The invasion continuum is classically described from a temporal point of view, where a species overcomes a defined number of barriers linked to the environment. First, an exotic species has to get through the geographical barrier, in order to be introduced in the new area. When introduced, the species has to face the new environmental conditions and survive to start the naturalization phase. When the environmental barrier is overcome, i.e. when the species is able to reproduce and its populations are self-sufficient, it has to overcome the dispersal barrier to spread in the ecosystem and finally become invasive. Within a given continent, a species could have overcome a variable number of barriers depending on the considered area. One can observe depending on the geographical zone some non-naturalized populations that cannot survive without a human introduction of new propagules, some naturalized populations that are not invasive yet, and some invasive populations. This geographical variation may be the result of a variation of the environmental conditions at the continental scale. The common ragweed (Ambrosia artemisiifolia L.) invasion in Western Europe is a good opportunity to study this aspect of the invasion biology. The invasion history and the species distribution are well documented, and highlight a geographical variation of the invasion dynamic. This is particularly clear in Western Europe, where lies a contrast between the highly invaded zone of the South of France, and the areas that are farther north (e.g. the North of France, Belgium, and the Netherlands). In this work, the general objective was to determine if this situation will remain stable or not, by assessing if the local climate and the interspecific competition were liming the species expansion northward. In order to answer this general objective, four different questions were asked: 1) Is the climate and/or the interspecific competition causing a plant performance variation within the different areas of the introduced range in Western Europe?; 2) Is the local climate allowing the establishment and the reproduction of newly introduced populations north to the current invaded range, in an agricultural habitat?; 3) What is the role of the morphological variability of the seeds in the invasion of areas experiencing rigorous climatic conditions?; and 4) What is the role of the priority effect in the species establishment? The results showed that once introduced in an agricultural habitat outside the current invaded range, the species was able to establish self-sustaining populations. On average, each plant produced a number of offspring equal to 273 ± 18.4 (mean ± standard error). In ruderal habitats, populations already exist in Belgium and in the South of The Netherlands, and are able to produce a high quantity of seeds: on average, measured plants carried 222± 32.0 seeds. The measured plant performances were similar to those measured within the invaded area. No limit to the colonization of the area beyond the current invaded range was found in this study. The local climate and the interspecific competition did not appear to limit the naturalization of the species in the studied area, which is located north to the current invaded range, in agricultural or ruderal situations. This work highlighted the obsolescence of the species status in Belgium, and illustrated the dynamic aspect of the invasion. The results showed the importance of the temporality in the colonization of disturbed habitats. When the species started its development a few weeks before the rest of the community, its performance was decupled, and this increase was higher than the one other Asteraceae ruderals species showed in the same position: its above ground biomass was 30.5 ± 1.94 times higher, and the number of flower heads 570 ± 160 times more important.. The high variability of the species observed all along this work is probably playing an important role in the invasion success. The high variability of the seeds morphology can widen the range of environmental conditions of the habitats the species is able to colonize. In addition, the plasticity of the morphological traits of the plant in response to climate and competition appeared to allow the species to maintain a good performance, even in stressful conditions. The results of this work suggest an invasion potential north to the current invaded area in Western Europe. In this uncertain situation, it appears critical to implement structure allowing the early detection of the species. This early detection may allow the eradication of the species before that the invasion was as problematic as in France. Sensitization campaigns of the agricultural sector should be encouraged in Belgium in order to avoid new occurrence of the species in field to be overlooked. These measures could allow the dispersion to remain a limiting factor for the invasion process in Belgium. [less ▲]

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See detailA useful result related with zeros of continuous compactly supported mother wavelets
Ayache, Antoine; Esser, Céline ULg

E-print/Working paper (2016)

In the last two decades, wavelet bases and associated methodologies have become quite important in many domains, such as signal and image processing, harmonic analysis, statistics, and so on. More ... [more ▼]

In the last two decades, wavelet bases and associated methodologies have become quite important in many domains, such as signal and image processing, harmonic analysis, statistics, and so on. More recently, they also turn out to be quite useful in the probabilistic framework of stochastic processes, in which, among other things, they allow to obtain fine results concerning erratic sample paths behavior. The goal of our article is to derive a result, related with zeros of continuous compactly supported mother wavelets, which is useful in this probabilistic framework. More precisely, let $\psi$ be any arbitrary such wavelet; we show that being given an arbitrary point $x_0\in\R$ there always exists at least one integer $k_{x_0}\in\Z$ such that $\psi(x_0-k_{x_0}) \neq 0$. [less ▲]

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See detailStein's method for comparison of univariate distributions
Swan, Yvik ULg; Reinert, Gesine; Ley, Christophe

E-print/Working paper (2016)

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See detailNonparametric control charts: economic statistical design
Marcos Alvarez, Alejandro ULg; Heuchenne, Cédric ULg; Faraz, Alireza ULg

E-print/Working paper (2016)

This paper studies economic statistical designs (ESD) for nonparametric control charts based on the sign and Wilcoxon tests. The main advantage of the procedures is that, except for the tested location ... [more ▼]

This paper studies economic statistical designs (ESD) for nonparametric control charts based on the sign and Wilcoxon tests. The main advantage of the procedures is that, except for the tested location parameter, they do not use either any parametric distribution for the quality characteristic or any information about the possible involved parameters, neither in the in-control nor in the out-of-control state. This is made possible by minimizing a cost function specified independently of these quantities. Unlike the ESD for the $\overline{x}$ chart, the resulting charts designs are robust to changes of the distributions of the observations (in control or out of control), provide reliable statistical guarantees when the $\overline{x}$ chart ESD does not and stay competitive even when the strong assumptions of the $\overline{x}$ chart ESD are fully satisfied. These new techniques can therefore be applied to a definitely wider class of problems and their designs may stay constant over time without losing performance. [less ▲]

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See detailOnline Learning for Strong Branching Approximation in Branch-and-Bound
Marcos Alvarez, Alejandro ULg; Wehenkel, Louis ULg; Louveaux, Quentin ULg

E-print/Working paper (2016)

We present an online learning approach to variable branching in branch-and-bound for mixed-integer linear problems. Our approach consists in learning strong branching scores in an online fashion and in ... [more ▼]

We present an online learning approach to variable branching in branch-and-bound for mixed-integer linear problems. Our approach consists in learning strong branching scores in an online fashion and in using them to take branching decisions. More specifically, numerical scores are used to rank the branching candidates. If, for a given variable, the learned approximation is deemed reliable, then the score for that variable is computed thanks to the learned function. If the approximation is not reliable yet, the real strong branching score is used instead. The scores that are computed through the real strong branching procedure are fed to the online learning algorithm in order to improve the approximated function. The experiments show promising results. [less ▲]

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See detailOn the processing of red pigment by late mousterian Neanderthals in Ormesson, Seine-et-Marne, France, 47000 years ago
Salomon, Hélène ULg; Bodu, Pierre; Geurten, Stéphanie et al

E-print/Working paper (2016)

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See detailBispecial factors in the Brun S-adic system
Labbé, Sébastien ULg; Leroy, Julien ULg

E-print/Working paper (2016)

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See detailA stroll along the gamma
Arras, Benjamin ULg; Swan, Yvik ULg

E-print/Working paper (2016)

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Peer Reviewed
See detailFundamentals for an International Typology of Social Enterprise Models
Defourny, Jacques ULg; Nyssens, Marthe

E-print/Working paper (2016)

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See detailRossano Rosi, "Hanska": un roman en "feuilleté"
Demoulin, Laurent ULg

E-print/Working paper (2016)

Compte rendu du beau roman de Rossano Rosi "Hanska"

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See detailHST-Juno synergistic approach of Jupiter's magnetosphere and ultraviolet auroras
Grodent, Denis ULg; Bonfond, Bertrand ULg; Gérard, Jean-Claude ULg et al

E-print/Working paper (2016)

Jupiter's system is not only fundamental to our understanding of the solar system but also of planetary systems around other stars as well as more distant astrophysical bodies, not accessible to a ... [more ▼]

Jupiter's system is not only fundamental to our understanding of the solar system but also of planetary systems around other stars as well as more distant astrophysical bodies, not accessible to a detailed investigation. Fully exploiting any rare opportunity to explore the Jovian system through synergistic observations is thus critical, as it will impact significantly across wider astronomical studies. Such an exceptional opportunity will occur in Cycle 24, when the NASA Juno spacecraft will achieve its prime mission around Jupiter. Since Juno will literally fly through the auroral acceleration regions, the combination of HST auroral observations with Juno in situ measurements will allow us to finally unravel the origins and consequences of Jupiter's powerful and highly variable ultraviolet auroras. This occasion has never occurred before and is unlikely to ever repeat. Juno will address key scientific issues related to unexplored regions of the Jovian magnetosphere. The auroral signatures associated with these magnetospheric processes will be precisely observed with STIS and COS. This program responds to the UV initiative and is only possible during Cycle 24. Indeed, HST is the only observatory capable of making these high spatial and temporal resolution FUV observations during the Juno mission. This ambitious campaign will yield high-impact results and significantly augment the science return of the NASA Juno mission. [less ▲]

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See detailFisheries reforms and right-based fisheries: insights from community fisheries across Cambodia
Chap, Sreyphea; Touch, Panha; Diepart, Jean-Christophe ULg

E-print/Working paper (2016)

The working paper uses a right-based approach to examine recent wave of reforms in the Cambodian fisheries sector and what these reforms mean for community fisheries management.

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See detailALPI project - Green Incentives : Belgian and European Aspects
Bourgeois, Marc ULg; Vanrykel, Fanny ULg; Defoy, Xavier ULg

E-print/Working paper (2016)

Finance is one of the main critical issues for the development of a low-carbon society especially during times of economic recession. Closing this green investment gap will require policy intervention ... [more ▼]

Finance is one of the main critical issues for the development of a low-carbon society especially during times of economic recession. Closing this green investment gap will require policy intervention. The ALPI project will concentrate on promoting relevant ins truments to accelerate the transition towards a low-carbon society by demonstrating the performance and impact of policy instruments on economic, government budget and environmental aspects. [less ▲]

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See detailFeasibility-oriented Branching Strategies for Global Optimization
Gerard, Damien ULg; Köppe, Matthias; Louveaux, Quentin ULg

E-print/Working paper (2016)

We study the spatial Brand-and-Bound algorithm for the global optimization of nonlinear problems. In particular we are interested in a method to find quickly good feasible solutions. Most spatial Branch ... [more ▼]

We study the spatial Brand-and-Bound algorithm for the global optimization of nonlinear problems. In particular we are interested in a method to find quickly good feasible solutions. Most spatial Branch-and-Bound-based solvers use a non global solver at a few nodes to try to find better incumbents. We show that it is possible to improve the branching rules and the node priority by exploiting the solutions from the non global solver. We also propose several smart adaptive strategies to choose when to run the non global solver. We show that despite the time spent in solving many more NLP problems in the nodes, the new strategies enable the algorithm to find the first good incumbents faster and to prove the global optimality faster. Numerous easy, medium size as well as hard NLP instances from the Coconut library are benchmarked. All experiments are run using the open source solver Couenne. [less ▲]

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See detailSpousal and survivor benefits in option value models of retirement: an application to Belgium
Jousten, Alain ULg; Lefebvre, Mathieu ULg

E-print/Working paper (2016)

We study retirement incentives with augmented option value model à la Stock and Wise (1990). We propose methodological extensions to better reflect the respective incentives faced by singles and couples ... [more ▼]

We study retirement incentives with augmented option value model à la Stock and Wise (1990). We propose methodological extensions to better reflect the respective incentives faced by singles and couples. Our results show that a more comprehensive modelling of couples’ incentives leads to very different patterns of retirement incentives – particularly for women. We apply the new indicators to data from the Survey of Health, Ageing and retirement in Europe (SHARE) in Belgium and find two key results. First, contrary to several previous studies, we obtain a positive signed income effects. Second, we find very different retirement incentives for men and women, with little flexibility in the retirement decision for men and substantially more flexibility for women as a function of financial incentives and household composition. [less ▲]

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See detailChinese State Capitalism and Western Antitrust Policy
Petit, Nicolas ULg

E-print/Working paper (2016)

Enthused by China’s conversion to the free market system in 1978 and its adoption of Western-style market institutions, the world has spent the last few decades turning a blind eye to China’s real ... [more ▼]

Enthused by China’s conversion to the free market system in 1978 and its adoption of Western-style market institutions, the world has spent the last few decades turning a blind eye to China’s real “governance” problem: that a shadow Party-State system permeates all branches of the economy. Whatever Washington-consensus style institutions are put in place, whatever State Owned Enterprise (“SOE”) reform is introduced, corporate and market governance occur under the rule of the Chinese Communist Party (“CCP”). And the CCP’s guidebook is the Leninist command that the whole of society shall be run as “single country-wide State syndicate”. This paper contends that China’s syndicated economic organization is akin to a “supertrust”, and that this creates conditions that are conducive to antitrust problems to which the Western world must awaken. In this context, this paper advances that the antitrust regulators of North America, Europe and elsewhere should take two simple, pragmatic steps under merger control and antitrust rules. In merger review, antitrust agencies should treat all SOEs and Privately Owned Enterprises (POEs) with a CCP cell as one unitary group and undertake a thorough competitive assessment of transactions on this basis. In addition, antitrust cases involving Chinese firms should be investigated on the default assumption that there is an underlying coordination scheme among them. [less ▲]

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See detailSize and Value Matter But Not the Way You Thought
Lambert, Marie ULg; Fays, Boris ULg; Hübner, Georges ULg

E-print/Working paper (2016)

We propose a simple but fundamental methodological change to Fama and French (1993) factor construction procedure. Consistent with Lambert and Hübner (2013) sequential sorting procedure to classify stocks ... [more ▼]

We propose a simple but fundamental methodological change to Fama and French (1993) factor construction procedure. Consistent with Lambert and Hübner (2013) sequential sorting procedure to classify stocks, our methodology controls ex ante for pricing errors produced by multifactor models. Our size and value factors deliver less specification errors when used to price portfolios, especially regarding low size and high B/M stocks. Furthermore, this alternative framework generates much stronger “turn-of-the-year” size and “through-the-year” book-to-market effects than conventionally documented. The factors also display a slight competitive advantage on the taxonomy of low turnover market anomalies defined by Novy-Marx and Velikov (2015). [less ▲]

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See detailSustainability of users' commitment to Living Labs: an exploratory research
Elsen, Catherine ULg; Vigneron, Lara ULg; Acconcia, Alessandro ULg

E-print/Working paper (2016)

This paper investigates why end-users sometimes find difficult to fully invest themselves in a Living Lab initiative, at least on the long run. The paper builds insights on the basis of users’ feedback ... [more ▼]

This paper investigates why end-users sometimes find difficult to fully invest themselves in a Living Lab initiative, at least on the long run. The paper builds insights on the basis of users’ feedback about four projects currently managed by the Wallonia e-health Living Lab (WeLL) and pave the way for renewed models of interaction that could lead to sustainable satisfaction and commitment of end-users. [less ▲]

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See detailNonlinear dynamical tunneling of optical whispering gallery modes in the presence of a Kerr nonlinearity
Shim, Jeong -Bo ULg; Schlagheck, Peter ULg; Hentschel, Martina et al

E-print/Working paper (2015)

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See detailIdentification of the concepts at stake during a consultation. Clinical exercises
Jamoulle, Marc ULg

E-print/Working paper (2015)

During a consultation between a patient and a doctor, symptoms, process and health problems are at stake and could be identified and retrieved through the use of ICPC.(refer to www.ph3c.org) Specific ... [more ▼]

During a consultation between a patient and a doctor, symptoms, process and health problems are at stake and could be identified and retrieved through the use of ICPC.(refer to www.ph3c.org) Specific training and managerial competences of the doctor could be identified and explained through the Q-Codes Together ICPC and Q-Codes form 3CGP ; Core Content Classification in General Practice/ Family Medicine The concepts identified in ICPC and Q-Codes could be useful to understand and teach the content of consultation in family medicine. [less ▲]

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See detailFestivals Acadiens et Creoles
Sacré, Robert ULg

E-print/Working paper (2015)

Comptes-rendus avec photos et liens Internet : 1) Houston et Galveston ( TX) 2) Festivals Acadiens et Créoles à Lafayette ( LA) jours 1 , 2 et 3 3) Lafayette by night

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See detailWhy Did the Industrial Revolution Start in Britain?
Van Neuss, Leif ULg

E-print/Working paper (2015)

The main goal of this paper is to provide an integrated overview of the literature devoted to identifying the causes of the British industrial revolution. Why did the industrial revolution, a fascinating ... [more ▼]

The main goal of this paper is to provide an integrated overview of the literature devoted to identifying the causes of the British industrial revolution. Why did the industrial revolution, a fascinating and multifaceted event which brought about modern economic growth, occur in eighteenth-century Britain? This question has animated a lot of discussions among scholars and is still nowadays heatedly debated in the literature. This debate is reflected in the large spectrum of theories which aim at explaining the true origins of the British industrialization. The paper first sheds light on a rising debate concerning the evolution of British incomes per capita before the British industrial revolution and the “Great Divergence”. The paper then investigates the proposed causes of the British industrialization, aggregating them into seven broad categories, i.e. (1) geography and natural resources, (2) demography, (3) agricultural progress, (4) demand-side factors, (5) trade and empire, (6) institutional and political factors, (7) science, technology, and human capital. [less ▲]

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See detailFrom 'Risk Communication' to Participatory Radiation Risk Assessment
Shirabe, Masashi; Fassert, Christine; Hasegawa, Reiko ULg

E-print/Working paper (2015)

In the aftermath of the Fukushima nuclear accident, many of the post¿disaster responses undertaken by the Japanese government sparked vivid debates and criticisms from the civil society. The article ... [more ▼]

In the aftermath of the Fukushima nuclear accident, many of the post¿disaster responses undertaken by the Japanese government sparked vivid debates and criticisms from the civil society. The article examines the post-accidental management of the authorities, with a special focus on their risk communication, and explores what went wrong in the process. It deals with the issues of risk assessment, expertise, counter-expertise, policy-makings, stakeholder participation, and trust in crisis and disaster situations. [less ▲]

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See detailLarge neighborhood search for multi-trip vehicle routing
François, Véronique ULg; Arda, Yasemin ULg; Crama, Yves ULg et al

E-print/Working paper (2015)

We consider two large neighborhood search approaches for the multi-trip vehicle routing problem, where each vehicle can perform several routes during the working shift to serve a set of customers. The ... [more ▼]

We consider two large neighborhood search approaches for the multi-trip vehicle routing problem, where each vehicle can perform several routes during the working shift to serve a set of customers. The problem specifically arises when customers are close to each other and/or when the demands are large. A common approach in the literature consists in solving this problem by mixing vehicle routing heuristics with bin packing routines to assign routes to vehicles. We compare this approach with the use of specific operators designed to tackle the routing and the assignment aspects of the problem simultaneously. We provide several best known solutions for benchmark instances. At the end of the work, we give insights about the proposed algorithm configurations by analyzing the behavior of several method components. [less ▲]

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Peer Reviewed
See detailQui ne risque rien n'a rien... Ou comment la Cour européenne des droits de l'homme incite le justiciable à éprouver la protection de ses droits fondamentaux devant son juge national
Rosoux, Géraldine ULg

E-print/Working paper (2015)

L'article analyse la décision Gherghina c. Roumanie du 9 juillet 2015, qui rejette une requête pour défaut d'épuisement des voies de recours internes.

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See detail25 novembre 2015 : cent ans de Relativité
De Rop, Yves ULg

E-print/Working paper (2015)

La théorie proposée par Einstein au début du XXe siècle porte bien mal son nom; car si, historiquement, l'accent fut mis d'abord sur la relativité de certaines notions (en particulier, la mesure de l ... [more ▼]

La théorie proposée par Einstein au début du XXe siècle porte bien mal son nom; car si, historiquement, l'accent fut mis d'abord sur la relativité de certaines notions (en particulier, la mesure de l'intervalle de temps écoulé entre deux événements donnés), on a compris par la suite qu'elle reposait plus fondamentalement sur l'existence de quantités absolues, c'est-à-dire, dont la mesure est identique pour tous les observateurs, quel que soit leur état de repos ou de mouvement. Ces quantités sont inconnues de la mécanique de Newton, laquelle ne reconnaît qu'un seul invariant : le temps. Ce texte cherche à retracer, avec un minimum de formalisme, comment s'est imposé un nouveau cadre géométrique pour la physique, dominé par cette exigence d'invariance des mesures spatio-temporelles et intégrant une description révolutionnaire de la gravitation. [less ▲]

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See detailElmore D. L'intégrale Frémeaux et Ass.
Sacré, Robert ULg

E-print/Working paper (2015)

Compte rendu Coffret 5 CDs + livret . La Wallon et le Blues , un mariage réussi

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See detailMars nighttime aurora
European Space Agency, ESA/ATG medialab; Gérard, Jean-Claude ULg; Soret, Lauriane ULg

E-print/Working paper (2015)

Press release by the European Space Agency (ESA) on the occasion of the publication in two journals of the peer-reviewed literature

Detailed reference viewed: 24 (1 ULg)
Peer Reviewed
See detailRebates and Article 102 TFEU: The European Commission's Duty to Apply the Guidance Paper
Petit, Nicolas ULg

E-print/Working paper (2015)

This paper shows that the European Union (EU) courts' case-law and general principles of EU law place the European Commission (“Commission”) under a duty to apply the Guidance Communication on Enforcement ... [more ▼]

This paper shows that the European Union (EU) courts' case-law and general principles of EU law place the European Commission (“Commission”) under a duty to apply the Guidance Communication on Enforcement Priorities (“Guidance Paper”) in abuse of dominance cases started after its adoption. This duty includes the obligation to test Article 102 TFEU cases under the As Efficient Competitor (“AEC”) framework, as set out in the 2009 Guidance Paper. The judgments handed down by the Union courts in Intel v Commission and Post Danmark II do not alter in any way the Commission’s “self binding” duty to apply the Guidance Paper. If the Commission wishes to depart from the AEC framework, it must officially withdraw its Guidance Paper. [less ▲]

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See detailLes Nouveaux Réactionnaires : mythe ou réalité ?
Durand, Pascal ULg; Sindaco, Sarah ULg; Devecchio, Alexandre

E-print/Working paper (2015)

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See detailMulti-period vehicle allocation with uncertain transportation requests
Crama, Yves ULg; Pironet, Thierry ULg

E-print/Working paper (2015)

This work investigates optimization techniques for a multi-period vehicle allocation problem with uncertain requests. A company owning a limited fleet of trucks attempts to maximize its operational profit ... [more ▼]

This work investigates optimization techniques for a multi-period vehicle allocation problem with uncertain requests. A company owning a limited fleet of trucks attempts to maximize its operational profit over an infinite horizon by optimally assigning transportation orders to the vehicles. Its profit stems from profits collected when transporting full truckloads, minus costs incurred when waiting or when moving unladen. The stochastic component of the problem arises from the uncertainty on the realization of each transportation order. The methodology is based on optimizing decisions for deterministic scenarios. Several policies are generated in this way, either by simple heuristics, or by more complex approaches, such as consensus and restricted expectation algorithms, or from network flow formulations over subtrees of scenarios. Myopic and a-posteriori deterministic optimization models are used to compute bounds allowing for performance evaluation. Numerical experiments are performed on various instances featuring different numbers of orders, graph sizes, sparsity, and probability distributions, and the performance of the algorithms is assessed by statistical tests. The robustness of various policies with respect to erroneous evaluations of the probability distributions is also analyzed. [less ▲]

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See detailL’accompagnement de projets d’entrepreneuriat social dans leurs phases initiales
Dufays, Frédéric ULg; Lovens, Caroline ULg; Mertens de Wilmars, Sybille ULg

E-print/Working paper (2015)

L’entrepreneuriat social connaît depuis quelques années un intérêt croissant. Mais pour les entrepreneurs sociaux, concilier les dimensions sociales et économiques demande de faire face à des défis bien ... [more ▼]

L’entrepreneuriat social connaît depuis quelques années un intérêt croissant. Mais pour les entrepreneurs sociaux, concilier les dimensions sociales et économiques demande de faire face à des défis bien spécifiques. Ne faut-il donc pas favoriser un accompagnement sur-mesure et modulable ? C’est le défi qu’a choisi de relever en Belgique francophone le programme ImpulCera en proposant aux entrepreneurs sociaux un soutien financier pour la réalisation d’une étude de faisabilité et pour le lancement de leur projet. Le présent article présente quelques résultats de l’évaluation de ce programme ainsi que les enseignements qui peuvent en être dégagés. [less ▲]

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See detailPour analyser la qualité des médicaments
Ziemons, Eric ULg

E-print/Working paper (2015)

Technique permettant de décortiquer les caractéristiques chimiques et physiques des molécules, la spectroscopie vibrationnelle est précieuse dans le domaine pharmaceutique. Les chercheurs du laboratoire ... [more ▼]

Technique permettant de décortiquer les caractéristiques chimiques et physiques des molécules, la spectroscopie vibrationnelle est précieuse dans le domaine pharmaceutique. Les chercheurs du laboratoire de Chimie Analytique de l’Université de Liège, spécialistes dans ce domaine de recherche, collaborent régulièrement avec des entreprises pharmaceutiques pour contrôler leurs matières premières, produits finis et procédés. [less ▲]

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See detailThe HARPS search for southern extra-solar planets. XXXVIII. Bayesian re-analysis of three systems. New super-Earths, unconfirmed signals, and magnetic cycles
Díaz, R. F.; Ségransan, D.; Udry, S. et al

E-print/Working paper (2015)

We present the analysis of the entire HARPS observations of three stars that host planetary systems: HD1461, HD40307, and HD204313. The data set spans eight years and contains more than 200 nightly ... [more ▼]

We present the analysis of the entire HARPS observations of three stars that host planetary systems: HD1461, HD40307, and HD204313. The data set spans eight years and contains more than 200 nightly averaged velocity measurements for each star. This means that it is sensitive to both long-period and low-mass planets and also to the effects induced by stellar activity cycles. We modelled the data using Keplerian functions that correspond to planetary candidates and included the short- and long-term effects of magnetic activity. A Bayesian approach was taken both for the data modelling, which allowed us to include information from activity proxies such as $\log{(R'_{\rm HK})}$ in the velocity modelling, and for the model selection, which permitted determining the number of significant signals in the system. The Bayesian model comparison overcomes the limitations inherent to the traditional periodogram analysis. We report an additional super-Earth planet in the HD1461 system. Four out of the six planets previously reported for HD40307 are confirmed and characterised. We discuss the remaining two proposed signals. In particular, we show that when the systematic uncertainty associated with the techniques for estimating model probabilities are taken into account, the current data are not conclusive concerning the existence of the habitable-zone candidate HD40307 g. We also fully characterise the Neptune-mass planet that orbits HD204313 in 34.9 days. [less ▲]

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See detailLe syndrome coup de sang
Courouce-Malblanc, Anne; Daix, Charlène; Ferry, Bénédicte et al

E-print/Working paper (2015)

Le coup de sang est un terme utilisé pour nommer une myopathie brutale consécutive à un exercice qui se manifeste cliniquement par des crampes douloureuses et une urine de couleur anormalement foncée du ... [more ▼]

Le coup de sang est un terme utilisé pour nommer une myopathie brutale consécutive à un exercice qui se manifeste cliniquement par des crampes douloureuses et une urine de couleur anormalement foncée du fait de l’élimination de la myoglobine des cellules musculaires détruites (myoglobinurie). [less ▲]

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See detailCeci n’est pas un conseil !
Choffray, Jean-Marie ULg

E-print/Working paper (2015)

La « Grande Récession de 2008 » a un mérite. Un seul ! Elle a rendu public le fait que personne ne savait exactement ce qui s’était passé, ni ce qui se passait. Pourquoi une telle crise de confiance avait ... [more ▼]

La « Grande Récession de 2008 » a un mérite. Un seul ! Elle a rendu public le fait que personne ne savait exactement ce qui s’était passé, ni ce qui se passait. Pourquoi une telle crise de confiance avait-elle vu le jour ? Quelles en seraient les conséquences ? Toutes et tous se sont trompés, y compris les meilleurs. Même celles et ceux qui étaient convaincus d’avoir raison ! Plus que jamais, l’incertitude, la saine et souveraine incertitude, garantit la liberté de l’investisseur... et du professeur ! [less ▲]

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See detailMarkets flash graphs
Choffray, Jean-Marie ULg

E-print/Working paper (2015)

A graph is worth a hundred words... A good graph may suggest some new heuristics. And…, a series of excellent graphs may provide the backbone of a theory! The goal of this paper is to share a set of ... [more ▼]

A graph is worth a hundred words... A good graph may suggest some new heuristics. And…, a series of excellent graphs may provide the backbone of a theory! The goal of this paper is to share a set of graphs from multiple sources that offer as many flashes on current and past market conditions. Inevitably, these graphs reflect my own biases and questionings. They are not meant to induce any action aside, maybe, from their integration in a personal Information System. The Great Recession of 2008, whose consequences are still unfolding, has been for each of us a powerful invitation to modesty. We live in a world where improbable, unthinkable and impossible events happen every day... More than ever, it’s time to sit down, shut up, watch out, build graphs, and think… hard! [less ▲]

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See detailInstitutional repositories: it’s a matter of sticks and carrots
Rentier, Bernard ULg

E-print/Working paper (2015)

Detailed reference viewed: 246 (10 ULg)
See detailObserving the emergence of chaos in a many-particle quantum system
Tomkovic, Jiri; Muessel, Wolfgang; Strobel, Helmut et al

E-print/Working paper (2015)

Accessing the connection between classical chaos and quantum many-body systems has been a long-standing experimental challenge. Here, we investigate the onset of chaos in periodically driven two-component ... [more ▼]

Accessing the connection between classical chaos and quantum many-body systems has been a long-standing experimental challenge. Here, we investigate the onset of chaos in periodically driven two-component Bose-Einstein condensates, whose small quantum uncertainties allow for exploring the phase space with high resolution. By analyzing the uncertainties of time-evolved many-body states, we find signatures of elliptic and hyperbolic periodic orbits generated according to the Poincar\'e-Birkhoff theorem, and the formation of a chaotic region at increasing driving strengths. The employed fluctuation analysis allows for probing the phase-space structure by use of only short-time quantum dynamics. [less ▲]

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