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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 ULiege; Tulle, Emmanuelle

E-print/Working paper (2019)

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 detailHousing the multitude: struggling with impermanence and singularities
Van Rooyen, Xavier ULiege; Bianchi, Michaël ULiege

E-print/Working paper (2019)

Since the financial crisis of 2008, architecture must face growing conditions of instability. This rekindles the necessity to integrate the parameter of uncertainty into architectural design much like the ... [more ▼]

Since the financial crisis of 2008, architecture must face growing conditions of instability. This rekindles the necessity to integrate the parameter of uncertainty into architectural design much like the concerns developed by the radical architects of the 1960s. At that time, these architects associated with the Team X challenged the hegemonic claims of the modern theories and introduced new issues for architecture. They raised the questions of uncertainty, instability over time, and the growing importance of individualities, notably on the subject of the housing and its ability to integrate the inhabitant as an actor. They introduced concepts like the ‘aesthetics of change’ (Smithsons), the ‘open form’ (Hansen), ‘open aesthetic’ (Voelcker) and developed architectural theories regarding indétermination and fragmentation. Out of a synthesis of this theoretical background, we propose to withdraw a conceptual tool with which we review the approach of two contemporary architectural offices, particularly concerned by the question of housing for the great number and exploring notions of indeterminacy, uncertainty, open aesthetics and open structure in their achievements. Doing so, we aim to provide insights to engage with actual and future challenges in the field of housing architecture. [less ▲]

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

E-print/Working paper (2019)

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

E-print/Working paper (2019)

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

E-print/Working paper (2018)

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

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

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See detailHenry Clews: Twenty-Eight Years in Wall Street
Choffray, Jean-Marie ULiege

E-print/Working paper (2018)

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

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

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See detailTerminologia multilingue in medicina di famiglia Versione 2.5 italiana
Jamoulle, Marc ULiege; Demurtas, Jacopo; Pesolillo, Gabriella et al

E-print/Working paper (2018)

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See detailDoes Coriolis force influence the flow in shallow reservoirs?
Dewals, Benjamin ULiege

E-print/Working paper (2018)

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See detailGuidelines related to the use of an existing cavity (mine/quarry) as reservoir of a pumped storage hydroelectric facility
Cerfontaine, Benjamin ULiege; Ronchi, Benedicta; Archambeau, Pierre ULiege et al

E-print/Working paper (2018)

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

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

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See detailUn mathématicien contemporain emblématique: Sir William Timothy Gowers
Bair, Jacques ULiege

E-print/Working paper (2018)

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

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

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

E-print/Working paper (2018)

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

“Invest smarter…” I started this project two years ago. After several hundred hours of reading, thinking and writing, here they are: “One Thousand Tweets on The Art & Science of internet-Based Investing.” While producing them, my goal was to “show you the way”; to share my observations on the evolution of the world and the behavior of the financial markets; and, to illustrate the key heuristics that I learned over more than ten years, including the most recent, and turbulent, period. 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 much better... That’s my wish for you! [less ▲]

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See detailAphorismes mathématiques de J. Ellenberg
Bair, Jacques ULiege

E-print/Working paper (2018)

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

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

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

E-print/Working paper (2018)

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

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

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

E-print/Working paper (2018)

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

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

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

E-print/Working paper (2018)

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

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

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

E-print/Working paper (2018)

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

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

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See detailjerome.pelenc@gmail.com
Pelenc, Jerome; Frère, Bruno ULiege; Wallenborn, J et al

E-print/Working paper (2018)

The goal of this commentary is to bring to the forefront four majors ideas/hypotheses to stimulate the debate regarding sustainability transitions: (i) we argue that “local environmental resistances” (the ... [more ▼]

The goal of this commentary is to bring to the forefront four majors ideas/hypotheses to stimulate the debate regarding sustainability transitions: (i) we argue that “local environmental resistances” (the environmental justice movement) and “local economic/community alternatives” (the Transition, degrowth and alike movements) constitute the two faces of the same coin i.e. “the great transition toward sustainability” when transition is considered from a citizen, place-based and socio-political perspective; (ii) we argue that both of these two global decentralized movements are place-based, they are participating in the emergence of a place-based alterglobalism. Then, the role of place in creating spaces of re-politicization through opposition and experimentation should be acknowledged and more researched; (iii) if resistances and alternatives share some features in common, they also present differences that should be further investigated regarding their empowerment and politicization potential; and (iv) last but not the least, we stress the need for a more incarnated, politicized and place-based approach to “sustainability transitions” thus distancing us from the Transition Management approach. [less ▲]

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See detailA Multi-agent Simulator to Assess the Impact of Regulatory Frameworks on the Interaction between Consumers and Distribution System Operator
Manuel de Villena Millan, Miguel ULiege; Ernst, Damien ULiege; Gautier, Axel ULiege et al

E-print/Working paper (2018)

This paper proposes a simulation-based methodology for evaluating the effectiveness of various regulatory frameworks promoting the large-scale deployment of decentralised electricity generation resources ... [more ▼]

This paper proposes a simulation-based methodology for evaluating the effectiveness of various regulatory frameworks promoting the large-scale deployment of decentralised electricity generation resources (DERs) in distribution systems. Electricity consumers, prosumers, and the distribution system operator (DSO) are modelled as agents interacting with each other in an artificial environment which encapsulates the salient features of realistic regulatory frameworks, along with a set of assumptions on DER technology availability, performance, and costs. More precisely, the methodology enables to simulate the interactions between those agents in a great variety of environments in order to study the progressive deployment of DER as a function of its profitability, and also shows how this deployment impacts the remuneration mechanism of the DSO and the evolution of the distribution tariff. The methodology is illustrated on a case study considering 16 different regulatory environments and using data for Belgian DSOs. [less ▲]

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

E-print/Working paper (2018)

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

E-print/Working paper (2018)

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

E-print/Working paper (2018)

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

E-print/Working paper (2018)

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

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

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See detailThe Sociology of Critique Toward a Grammatical Approach of Action. The case of civic disobedience.
Frère, Bruno ULiege; Cervera-Marzal, Manuel

E-print/Working paper (2018)

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See detailSolidarity economy and its anarchist grammar
Frère, Bruno ULiege

E-print/Working paper (2018)

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

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

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

E-print/Working paper (2018)

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

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

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See detailFactoring Characteristics into Returns: A Clinical Approach to Fama-French Portfolio Decomposition
Lambert, Marie ULiege; Fays, Boris ULiege; Hübner, Georges ULiege

E-print/Working paper (2018)

This paper thoroughly analyzes competing construction methods for factoring characteristics into returns. We show the importance of ensuring a proper diversification of the factor's portfolio constituents ... [more ▼]

This paper thoroughly analyzes competing construction methods for factoring characteristics into returns. We show the importance of ensuring a proper diversification of the factor's portfolio constituents for producing relevant and unbiased risk factors or benchmark portfolios. This is an important issue to be solved for asset pricing and performance models defined as a function of characteristics. As a practical case, the paper works on the design of size and value spread portfolios à la Fama-French. This quasi- clinical investigation examines three methodological choices that have an impact on portfolio diversification: the (in)dependence and the (a)symmetry of the stock sorting procedure, and the sorting breakpoints. A sequential and symmetric sort of stocks into long and short portfolios conditioned on control variables produces unbiased factors. Our results are stronger when whole firm samples are used to define breakpoints and are also robust to the inclusion of a third dimension in the multiple sorting. [less ▲]

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See detailEstimation from cross-sectional data under a semiparametric truncation model
De uña Alvarez, Jacobo; Heuchenne, Cédric ULiege; Laurent, Géraldine

E-print/Working paper (2018)

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See detailNonparametric regression with cross-sectional data: an alternative to conditional product-limit estimators
Heuchenne, Cédric ULiege; Laurent, Géraldine

E-print/Working paper (2018)

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See detailPV adoption in Wallonia: The role of distribution tariffs under net metering
Gautier, Axel ULiege; Jacqmin, Julien ULiege

E-print/Working paper (2018)

The deployment of decentralized productions units (DPU) like rooftop solar panels is a major challenge for energy transition. Under a net metering system where the meter runs backward when there is ... [more ▼]

The deployment of decentralized productions units (DPU) like rooftop solar panels is a major challenge for energy transition. Under a net metering system where the meter runs backward when there is excessive PV production, the electricity produced is valued at the retail price. Higher retail prices thus encourage the deployment of DPU. In this paper, we study the impact of tariffs on the decision to install residential solar PV installations. We analyze a panel data from Wallonia, where tariffs depend largely from volumetric charges. We exploit the presence of 13 different grid operators with different tariffs, to disentangle this relationship. Using various specifications, our results suggest that a one eurocent per kWh of tariff increase leads to, all else equal, an increase of around 5% in the number of new installations. [less ▲]

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See detailPrioritization vs zero-rating: Discrimination on the internet
Gautier, Axel ULiege; Somogyi, Robert

E-print/Working paper (2018)

This paper analyzes two business practices on the mobile internet market, paid prioritization and zero-rating. Both violate the principle of net neutrality by allowing the internet service provider to ... [more ▼]

This paper analyzes two business practices on the mobile internet market, paid prioritization and zero-rating. Both violate the principle of net neutrality by allowing the internet service provider to discriminate different content types. In recent years these practices have attracted considerable media attention and regulatory interest. The EU, and until recently the US have banned paid prioritization but tolerated zero-rating under conditions. With prioritization, the ISP delivers content at different speeds and it is equivalent to a discrimination in terms of quality. With zero-rating, the ISP charges different prices for content and it is equivalent to a discrimination in terms of prices. We first show that neither of these practices lead to the exclusion of a content provider, a serious concern of net neutrality advocates. The ISP chooses prioritization when traffic is highly valuable for content providers and congestion is severe, and zero-rating in all other cases. Furthermore, investment in network capacity is suboptimal in the case of prioritization and socially optimal under zero-rating. [less ▲]

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See detailGeneration of Parallel Corpus for Low Resource Language Translation
Trieu, Long Hai; Ittoo, Ashwin ULiege

E-print/Working paper (2018)

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See detailAssessing and predicting review helpfulness: Critical review, open challenges and research agenda
Hoffait, Anne-Sophie ULiege; Ittoo, Ashwin ULiege; Schyns, Michael ULiege

E-print/Working paper (2018)

The issues of determining what makes a customer review helpful and how to predict review helpfulness have received significant attention in recent years. However, the current literature is highly ... [more ▼]

The issues of determining what makes a customer review helpful and how to predict review helpfulness have received significant attention in recent years. However, the current literature is highly heterogeneous with contradictory findings. We critically synthesize extant literature and identify factors responsible for these contradictions which we classify into four dimensions, viz. datasets, features, approach and review helpfulness operationalization, and clarify the prevailing confusion. We highlight research gaps, and propose novel research directions to bridge them and to advance the state-of-the-art. We provide resources such as synthetic tables, which summarize past research and develop a (future) research roadmap. These resources not only provide a concise overview of current research, but also illustrate its heterogeneity and serve as a valuable basis to ground future research. [less ▲]

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See detailUse of high-resolution seismic reflection data in the paleogeographical reconstruction of shallow Lake Yamanaka (Fuji Five Lakes, Japan)
Lamair, Laura ULiege; Hubert, Aurelia ULiege; Yamamoto, S. et al

E-print/Working paper (2018)

High-resolution seismic profiles combined with the integration of published drilling data provide a detailed paleoenvironmental history of Lake Yamanaka (Fuji Five Lakes, Japan). This study presents a ... [more ▼]

High-resolution seismic profiles combined with the integration of published drilling data provide a detailed paleoenvironmental history of Lake Yamanaka (Fuji Five Lakes, Japan). This study presents a detailed analysis of different depositional stages of the current Lake Yamanaka (floodplain wetland, river and lake). From ca. 5500 cal yr BP to ca. 5050 cal yr BP, the Yamanaka Basin was occupied by floodplain wetlands. During that period, the landscape was very stable and the erosion on northeastern flank of Mt. Fuji was relatively limited. From ca. 5050 cal yr BP to ca. 3050 cal yr BP, the water level increased and the floodplain wetlands became a lake. From ca. 3050 cal yr BP to ca. 2050 cal yr BP, water level decreased progressively leading to a reduction of lake extension. During the lowering of lake water level, a 1 km2 mass-transport deposit modified the physiography of the lakefloor. From ca. 2050 cal yr BP to ca. 1050 cal yr BP, the lake disappeared and the depression was occupied by a river flowing toward the northwest. Morphological lows formed by mass-transport deposit were occupied by ponds. From ca. 1050 cal yr BP to present day, the lake water rose again connecting the pond with the main lake. Since then, lake water level continues to rise up to the current lake water level. Lake water level fluctuations are the results of several factors that could be concomitant: (i) change in precipitation rate; (ii) margin destabilization (the Yamanaka MTD); (iii) change in river inlets and therefore variation of water supplies; (iv) volcanic eruptions (scoria fall-out and lava flows); (v) change in vegetation cover. This study highlights the importance of coupling sediment cores and high-resolution seismic reflection profiling to identify lateral change and modification of the sedimentary inputs through time. [less ▲]

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See detailNumerical investigation on the seismic performance of aqueduct bridge structures: application to the Antioch on the Orontes Aqueduct (Antakya, Turkey)
Lamair, Laura ULiege; Hubert, Aurelia ULiege; Degée, Hervé et al

E-print/Working paper (2018)

Seismic shaking can damage building, especially historical structures which were not designed with building codes. Here we focus on Roman aqueduct bridge structures, which remains can be found all over ... [more ▼]

Seismic shaking can damage building, especially historical structures which were not designed with building codes. Here we focus on Roman aqueduct bridge structures, which remains can be found all over the Mediterranean area, a highly seismic region. We developed simple models using a finite element software to realize static and dynamic linear analyses of these structures when they are subject to imposed ground motion. The effects of basic variations in the pier-arch architectural design and in the type of material used were investigated. We identified two main weak zones: the arch extremities and the bottom part of the piers. The damage occurrence in these two areas could be attributed to earthquake shaking. Our first-order vulnerability analysis also points to different ways to enhance the structure stability: building narrow arches, adding buttress zones and using bricks which are light materials. Finally, we also investigated the vulnerability to seismic shaking of a real case example, the Antioch on the Orontes Aqueduct in Harbiye (Turkey). The aqueduct shows different stages of constructions, damage areas and repairs. The modeling suggests that the observed damages were the results of earthquake shaking. The repairs reinforced the structure and stabilized it pointing to the adaptive technology and skills of the roman engineers. [less ▲]

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See detailExtended main sequence turn-off originating from a broad range of stellar rotational velocities
Lim, Beomdu; Rauw, Grégor ULiege; Nazé, Yaël ULiege et al

E-print/Working paper (2018)

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See detailLate Holocene changes on erosion pattern on a lacustrine environment: landscape stabilization by volcanic activity versus human activity
Lamair, Laura ULiege; Hubert, Aurelia ULiege; El Ouhabi, Meriam ULiege et al

E-print/Working paper (2018)

Lacustrine sediments are particularly sensitive to modi cations within the lake catch- ment. In a volcanic area, sedimentation rates are directly a ected by the history of the volcano and its eruptions ... [more ▼]

Lacustrine sediments are particularly sensitive to modi cations within the lake catch- ment. In a volcanic area, sedimentation rates are directly a ected by the history of the volcano and its eruptions. Here, we investigate the impact of Mt. Fuji Volcano (Japan) on Lake Motosu and its watershed. The lacustrine in ll is studied by combining seismic re ec- tion pro les and sediment cores. We show evidence of changes in sedimentation patterns during the depositional history of Lake Motosu. The frequency of large mass-transport de- posits recorded within the lake decreases over the Holocene. Before 8000 cal yr BP, large sublacustrine landslides and turbidites were lling the lacustrine depression. After 8000 cal yr BP, only one large sublacustrine landslide was recorded. The change in sedimentation pattern coincides with a change in sediment accumulation rate. Over the last 8000 cal yrs BP, the sediment accumulation rate was not su cient enough to produce large sublacustrine slope failures. Consequently, the frequency of large mass-transport deposits decreased and only turbidites resulting from sur cial slope reworking occurred. These constitute the main sedimentary in ll of the deep basin. We link the change in sediment accumulation rate with (i) climate and vegetation changes; and (ii) the Mt. Fuji eruptions which a ected the Lake Motosu watershed by reducing its size and strongly modi ed its topography. Moreover, this study highlights that the deposition of turbidites in the deep basin of Lake Motosu is mainly controlled by the paleobathymetry of the lake oor. Two large mass-transport deposits, oc- curring around 8000 cal yr BP and 2000 cal yr BP, modi ed the paleobathymetry of the lake oor and therefore, changed the turbidite depositional pattern of Lake Motosu. [less ▲]

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See detailCompact quadratizations for pseudo-Boolean functions
Boros, Endre; Crama, Yves ULiege; Rodriguez Heck, Elisabeth ULiege

E-print/Working paper (2018)

The problem of minimizing a pseudo-Boolean function, that is, a real-valued function of 0-1 variables, arises in many applications. A quadratization is a reformulation of this nonlinear problem into a ... [more ▼]

The problem of minimizing a pseudo-Boolean function, that is, a real-valued function of 0-1 variables, arises in many applications. A quadratization is a reformulation of this nonlinear problem into a quadratic one, obtained by introducing a set of auxiliary binary variables. A desirable property for a quadratization is to introduce a small number of auxiliary variables. We present upper and lower bounds on the number of auxiliary variables required to define a quadratization for several classes of specially structured functions, such as functions with many zeros, symmetric, exact k-out-of-n, at least k-out-of-n and parity functions, and monomials with a positive coefficient, also called positive monomials. Most of these bounds are logarithmic in the number of original variables, and we prove that they are best possible for several of the classes under consideration. For positive monomials and for some other symmetric functions, a logarithmic bound represents a significant improvement with respect to the best bounds previously published, which are linear in the number of original variables. Moreover, the case of positive monomials is particularly interesting: indeed, when a pseudo-Boolean function is represented by its unique multilinear polynomial expression, a quadratization can be obtained by separately quadratizing its monomials. [less ▲]

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See detailPerformance sharing in risky portfolios: The case of hedge fund returns and fees
Lambert, Marie ULiege; Hübner, Georges ULiege

E-print/Working paper (2017)

Institutional investors face different types of leverage and short-sale restrictions that alter competition in the asset management industry. This distortion enables high-risk unconstrained investors (e.g ... [more ▼]

Institutional investors face different types of leverage and short-sale restrictions that alter competition in the asset management industry. This distortion enables high-risk unconstrained investors (e.g., equity long/short hedge fund managers) to extract additional income from constrained institutional investors. Using a sample of 1,938 long/short equity hedge funds spanning 15 years, we show that high-volatility funds deliver lower net-of-fees Sharpe ratios than do their low-volatility peers; furthermore, the managers of these funds usually charge higher fees. This evidence can be interpreted as a situational rent extraction or as compensation for the service of enhancing market functioning. [less ▲]

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See detailSeeking the Best Fundamental Risk Factors: A Clinical Approach to Fama-French Portfolio Decomposition
Lambert, Marie ULiege; Fays, Boris ULiege; Hübner, Georges ULiege

E-print/Working paper (2017)

This paper performs a thorough analysis of competing construction methods for the design of size (SMB) and value (HML) spread portfolios à la Fama-French. This quasi-clinical investigation of ... [more ▼]

This paper performs a thorough analysis of competing construction methods for the design of size (SMB) and value (HML) spread portfolios à la Fama-French. This quasi-clinical investigation of methodological choices uncovers substantial differences in the capacity of estimated premiums to translate stock characteristics into returns. A sequential sort of stocks into long and short portfolios conditioned on control variables (“pre-conditioning”) produces factors that best reflect the corresponding fundamental attributes. Our results are stronger when using the whole firm sample to define breakpoints and a triple sort, which ensures the same diversification (in terms of number of firms) across the characteristic-sorted portfolios forming the long and short legs of the factor. Our results are robust to the inclusion of the momentum dimension in the multiple sorting. The best method produces a volatile and insignificant size premium, but a high and stable value premium. [less ▲]

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See detailLaw, Cognitive Technologies & Artificial Intelligence. Session 1 : Introduction to A.I. and Regulation
Mansvelt, Valérie ULiege

E-print/Working paper (2017)

This session, at the Brussels School of Cognitive Technologies and Law, aims at giving meaning to the conceptual and practical impact of cognitive technologies and artificial intelligence (A.I.). The ... [more ▼]

This session, at the Brussels School of Cognitive Technologies and Law, aims at giving meaning to the conceptual and practical impact of cognitive technologies and artificial intelligence (A.I.). The point is not to provide answers but questions. This first session is a general session on Law and artificial intelligence with two representatives from the private and public sector. Bjoern Juretzki is a policy official in the EU working especially on A.I. in the development of policies at the European commission level. Jonathan Sage is a representative of the private sector who works for the Government and Regulatory Affairs at IBM. Nicolas Petit, Professor of Law at ULiège and a Research Professor at the School of Law of the University of South Australia, gave some context on the technologies and their legal implication. [less ▲]

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See detailA comparative study of labeling algorithms for vehicle routing problems with time windows and waiting time costs
Michelini, Stefano ULiege; Arda, Yasemin ULiege; Küçükaydın, Hande

E-print/Working paper (2017)

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See detailRapport sur l’égalité entre les femmes et les hommes à l’Université de Liège 2017- rapport genre 2017
Cornet, Annie ULiege

E-print/Working paper (2017)

this report present the statistical data of University de Liège (student and personal) for the year 2016-2017. Similar report in 2016 and 2014.

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See detailA Simulator to Explore Tarification Designs for Distribution Networks
Manuel de Villena Millan, Miguel ULiege; Gautier, Axel ULiege; Fonteneau, Raphaël ULiege et al

E-print/Working paper (2017)

This paper introduces a computational tool to help assess the impact of regulation policies within distribution net- works in the deployment of distributed renewable electricity generation. This tool is a ... [more ▼]

This paper introduces a computational tool to help assess the impact of regulation policies within distribution net- works in the deployment of distributed renewable electricity generation. This tool is a comprehensive multi-agent simulator capable of handling the interaction between the users of a distribution network and their distribution system operator. With this simulator, it is possible to address the different regulatory constraints encountered by distribution system operators, for any regulation policy. In the simulator, we model individual electricity consumers as rational agents, who may invest in optimised distributed renewable energy installations, if they are cost-efficient compared to the network tariff. By modelling the cost recovery scheme of the distribution system operator, the simulator then computes the evolution of the network tariff in response to a change in the consumption and generation of the consumers in the distribution network, due to the deployment of distributed generation. The simulator is illustrated with various regulation policies. [less ▲]

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See detailOn overfitting and asymptotic bias in batch reinforcement learning with partial observability
François-Lavet, Vincent ULiege; Ernst, Damien ULiege; Fonteneau, Raphaël ULiege

E-print/Working paper (2017)

This paper stands in the context of reinforcement learning with partial observability and limited data. In this setting, we focus on the tradeoff between asymptotic bias (suboptimality with unlimited data ... [more ▼]

This paper stands in the context of reinforcement learning with partial observability and limited data. In this setting, we focus on the tradeoff between asymptotic bias (suboptimality with unlimited data) and overfitting (additional suboptimality due to limited data), and theoretically show that while potentially increasing the asymptotic bias, a smaller state representation decreases the risk of overfitting. Our analysis relies on expressing the quality of a state representation by bounding L1 error terms of the associated belief states. Theoretical results are empirically illustrated when the state representation is a truncated history of observations. Finally, we also discuss and empirically illustrate how using function approximators and adapting the discount factor may enhance the tradeoff between asymptotic bias and overfitting. [less ▲]

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See detailMéditations expérimenées sur la TSUM (Transition Secondaire-Université en Mathématiques)
Bair, Jacques ULiege

E-print/Working paper (2017)

L’objectif de ce travail est de mettre par écrit quelques idées personnelles à propos de l’enseignement des mathématiques dans une première année de l’enseignement supérieur et ainsi de réfléchir à propos ... [more ▼]

L’objectif de ce travail est de mettre par écrit quelques idées personnelles à propos de l’enseignement des mathématiques dans une première année de l’enseignement supérieur et ainsi de réfléchir à propos de la transition entre le secondaire et l’Université (TSU, en abrégé) pour un cours de mathématiques. A cet effet, on compare les enseignements secondaire et universitaire, on précise une certaine conception des mathématiques et de leur enseignement au niveau de la TSU. Dans une première annexe se trouve également une étude plus théorique et technique sur la métacognition. Une particularité de ce travail est probablement de relier des idées issues de la littérature spécialisée relative à trois thèmes qui sont souvent développés indépendamment les uns des autres, à savoir l’épistémologie des mathématiques, la pédagogie universitaire et la didactique des mathématiques, le tout étant agencé d’après des convictions personnelles et des expériences professionnelles. [less ▲]

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See detailBalanced sequences of complexity 2n+1
Cassaigne, Julien; Labbé, Sébastien; Leroy, Julien ULiege

E-print/Working paper (2017)

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See detailLe coaching en questions
Absil, Gaëtan ULiege

E-print/Working paper (2017)

Cette note apporte des éléments de réponses aux questions adressées à l’APES-ULiège par Infor Santé – Alliance nationale des Mutualités chrétiennes à propos de la notion de « coaching ». Pour répondre aux ... [more ▼]

Cette note apporte des éléments de réponses aux questions adressées à l’APES-ULiège par Infor Santé – Alliance nationale des Mutualités chrétiennes à propos de la notion de « coaching ». Pour répondre aux questions, nous nous appuyons sur :  Les travaux et les réflexions menées dans le cadre des collaborations avec les acteurs de prévention et promotion de la santé  L’expertise de l’APES-ULiège en matière d’accompagnement  Une première revue de la littérature concernant le concept de coaching  Une exploitation des outils linguistiques du Centre National de Ressources Textuelles et Lexicales [less ▲]

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See detailBien raisonner en TSUM (Transition Secondaire-Université en Mathématiques)
Bair, Jacques ULiege

E-print/Working paper (2017)

Bien raisonner est assurément une des compétences clés que doivent acquérir et développer les étudiants entrant à l’Université. Nous y consacrons entièrement ce travail illustré par de nombreux exemples ... [more ▼]

Bien raisonner est assurément une des compétences clés que doivent acquérir et développer les étudiants entrant à l’Université. Nous y consacrons entièrement ce travail illustré par de nombreux exemples construits à partir de notre expérience professionnelle. En premier lieu, nous distinguons, à la suite de G. Polya, les raisonnements plausibles des raisonnements démonstratifs. Ensuite, nous nous intéressons à certains éléments de logique qui nous paraissent importants au niveau d’une TSUM. Puis, nous analysons la nature de preuves mathématiques à ce stade de l’apprentissage. Enfin, nous dissertons quelque peu sur l’usage des démonstrations dans l’enseignement. Ce travail se termine par deux annexes techniques, relatives respectivement à différents types de syllogismes et à quelques éléments plus formels de logique mathématique. [less ▲]

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See detailLes mathématiques: une science comme les autres ?
Bair, Jacques ULiege

E-print/Working paper (2017)

Les mathématiques sont-elles une science et, dans l'affirmative, sont-elles comparables aux autres disciplines scientifiques comme la physique, la biologie, ... ? Nous apportons des éléments de réponse à ... [more ▼]

Les mathématiques sont-elles une science et, dans l'affirmative, sont-elles comparables aux autres disciplines scientifiques comme la physique, la biologie, ... ? Nous apportons des éléments de réponse à de telles questions en basant principalement nos arguments sur la distinction, due au mathématicien-épistémologue G. Polya, entre les raisonnements plausibles ou démonstratifs. [less ▲]

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See detailLiens entre mathématiques et jeux
Bair, Jacques ULiege

E-print/Working paper (2017)

Le présent travail se compose de plusieurs parties. En premier lieu, nous définissons le concept général de jeu et présentons quelques mathématiciens célèbres, de toutes époques, qui étaient (ou sont ... [more ▼]

Le présent travail se compose de plusieurs parties. En premier lieu, nous définissons le concept général de jeu et présentons quelques mathématiciens célèbres, de toutes époques, qui étaient (ou sont encore) des adeptes de jeux mathématiques. Ensuite, nous établissons une typologie des jeux mathématiques. Une deuxième partie est consacrée à l’intervention des jeux dans l’enseignement des mathématiques. Nous donnons divers avantages des activités ludiques en classe, mais également des objections relatives à leur usage à des fins pédagogiques. Nous nous demandons aussi comment sélectionner un jeu pour des élèves et exhibons des exemples concrets de jeux exploitables en classe. Ce travail se termine par une bibliographie sur le sujet, ainsi que par une annexe composée de diapositives présentées lors d’un exposé réalisé à l’Université du Luxembourg dans le cadre de la Formation Pédagogique (FOPED) : nous y décrivons brièvement différentes épreuves ludiques proposées ces dernières années à des élèves de l’enseignement secondaire en France, Belgique et au Luxembourg. [less ▲]

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

E-print/Working paper (2017)

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 detailSur l'évaluation de compétences en mathématiques
Bair, Jacques ULiege

E-print/Working paper (2017)

Ce document comprend deux parties. Tout d’abord, un texte est consacré à des généralités sur la mesure de compétences, ainsi qu’à la présentation, illustrée par des exemples concrets, de différents types ... [more ▼]

Ce document comprend deux parties. Tout d’abord, un texte est consacré à des généralités sur la mesure de compétences, ainsi qu’à la présentation, illustrée par des exemples concrets, de différents types d’échelles (universelle, descriptive, globale) et de grilles d’évaluation. Enfin, ce travail se termine par la reproduction de diapositives (initialement réalisées à l’aide du logiciel Power Point) préparées pour accompagner une leçon sur l’évaluation ; l’exposé oral correspondant a été donné, dans le cadre de la FOPED (Formation Pédagogique), à plusieurs cohortes de stagiaires en mathématiques à l’Université du Luxembourg. [less ▲]

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See detailPetite apologie de l'analogie en mathématiques
Bair, Jacques ULiege

E-print/Working paper (2017)

L'analogie est souvent utilisée par les mathématiciens car elle s'avère déterminante très souvent dans la création de mathématiques nouvelles. Pour illustrer simplement ces propos, nous présentons deux ... [more ▼]

L'analogie est souvent utilisée par les mathématiciens car elle s'avère déterminante très souvent dans la création de mathématiques nouvelles. Pour illustrer simplement ces propos, nous présentons deux exemples, l'un de géométrie et l'autre d'analyse, qui ont été initialement développés par G. Polya. Une brève biographie de cet auteur est présentée en fin d'article. [less ▲]

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See detailQuelques idées générales à propos de la compréhension en mathématiques
Bair, Jacques ULiege

E-print/Working paper (2017)

Dans cet article, nous apportons des éléments de réponse à la question générale suivante : "Que signifie bien comprendre en mathématiques ?" Nous nous demandons pourquoi il est difficile d'y répondre et ... [more ▼]

Dans cet article, nous apportons des éléments de réponse à la question générale suivante : "Que signifie bien comprendre en mathématiques ?" Nous nous demandons pourquoi il est difficile d'y répondre et apportons une piste de solution en distinguant les activités de production de celles de reproduction. De plus, nous abordons le problème étudié d'un point de vue aussi bien local que global. Enfin, nous nous interrogeons sur l'incompréhension en mathématiques en proposant une typologie, en repérant des causes possibles d'incompréhension et en donnant quelques conseils pratiques. [less ▲]

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See detailImpact des valeurs responsables des médecins sur l’efficacité des services médicaux dans les CHU algériens : modélisation par les plans d’expériences
Bounazef, Djida ULiege; Van Caillie, Didier ULiege

E-print/Working paper (2017)

Medical doctors impact the efficiency of medical departments through their level of skill and engagement. The sensitivity of medical doctors on responsible and inclusive values fosters a stable work ... [more ▼]

Medical doctors impact the efficiency of medical departments through their level of skill and engagement. The sensitivity of medical doctors on responsible and inclusive values fosters a stable work climate that optimizes organizational efficiency and performance in UHCs’ departments. This reduces sources of nuisance and demotivation for optimal work stability, which induces efficiency’s improvement. The case study is done on 30 different services belonging to the Algerian UHCs in the purpose to build a model by the method of design of experiments. Multiple regression studies correlations between sensitivity to responsible values, work climate, workplace stability and efficiency of studied departments. It also allows to predict the improvement of departments’ efficiency according to the variation of dependent variables for optimizing the UHCs’ performance. The study’s results illustrate the strong correlation of sensitivity to responsible values and workplace stability’s variables on efficiency. They also highlight strong relations of interdependence between firstly responsible values and work climate, and secondly, between climate and workplace stability. [less ▲]

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See detailLa Ceinture Aliment-Terre Liégeoise : des initiatives locales au projet de transition territoriale
Feyereisen, Marlène ULiege; Stassart, Pierre M ULiege

E-print/Working paper (2017)

Depuis une dizaine d’années, des initiatives qui cherchent à territorialiser la production et la consommation de produits alimentaires se développent dans le paysage agroalimentaire wallon. Parmi celles ... [more ▼]

Depuis une dizaine d’années, des initiatives qui cherchent à territorialiser la production et la consommation de produits alimentaires se développent dans le paysage agroalimentaire wallon. Parmi celles-ci, la Ceinture aliment-terre liégeoise (CATL) est une dynamique qui s’est construite autour d’un diagnostic du système agroalimentaire conventionnel et propose des alternatives en région liégeoise. La CATL a pour caractéristique principale de constituer un « mouvement citoyen », c’est-à-dire qu’elle mobilise les citoyens dans la transformation du système agroalimentaire. Pour analyser cette initiative, nous allons retracer la trajectoire de la CATL depuis sa naissance jusqu’à aujourd’hui, ainsi que les dilemmes et questionnements auxquels elle a dû faire face tout au long de son évolution et comment elle propose d’y répondre. Cette analyse permet de comprendre que le potentiel de transformation de la CATL pour la transition réside surtout dans sa capacité à intégrer une série d’initiatives du territoire dans une vision commune pour construire une « niche globale territoriale » plus à même d’influencer le régime et d’engager une transition du système agroalimentaire liégeois et wallon. [less ▲]

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See detailLa dynamique de la controverse du piétonnier de Bruxelles
Charlery de la Masselière, Madeleine ULiege; Esnoul, Elise ULiege; Pfohl, Clémentine ULiege et al

E-print/Working paper (2017)

La dynamique de la controverse apparue autour du projet de piétonisation des boulevards centraux de la Ville de Bruxelles est relue à travers la théorie de l’acteur réseau (Callon &Latour 1986) . Ceci ... [more ▼]

La dynamique de la controverse apparue autour du projet de piétonisation des boulevards centraux de la Ville de Bruxelles est relue à travers la théorie de l’acteur réseau (Callon &Latour 1986) . Ceci permet de mettre en évidence deux traductions concurrentes : celle de la ville et celle de la Platform Pentagone. La ville a traduit son projet en organisant un réseau d’acteurs autour du point de passage obligé (PPO) suivant : « piétonniser les boulevards centraux pour stopper le transit automobile et faire du centre de Bruxelles un nouveau cœur urbain attractif ». La traduction de la Platform Pentagone, notre deuxième porte-parole, propose un autre point de passage obligé : « faire un piétonnier négocié, favorable à tous les usagers ». Cette formulation entre en concurrence directe avec celle de la ville. Chacune des deux problématisations illustre une conception différenciée de la notion de piétonnier ainsi que de ce qui est, ou non, négociable. Des dissidences apparaissent qui permettent de relever une série d’ambigüités au sein des réseaux et des diverses situations. [less ▲]

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See detailThe impact of external market conditions on R&D valuation
Lambert, Marie ULiege; Moreno, Manuel; Platania, Federico

E-print/Working paper (2017)

Traditional real options models regard the idiosyncratic risk of a project as the main value driver. Beyond the specific risks embedded in the project, i.e., both its technical and idiosyncratic risk, our ... [more ▼]

Traditional real options models regard the idiosyncratic risk of a project as the main value driver. Beyond the specific risks embedded in the project, i.e., both its technical and idiosyncratic risk, our model captures the interactions among different market, economic and social forces and their impact on R&D project valuation. Using Fourier series, our model aggregates external forces that play relevant roles in the process that determines the cash flow structure. Consequently, the posited model provides managers and policy makers with a powerful yet flexible tool to stress test several economic scenarios under which the project could develop. In a practical case, we apply our novel model and methodology to the valuation of a pharmaceutical R&D project and examine the impact of external forces on the optimal time to launch the project. The real options approach also allows for the possibility of optimally abandoning a project before completion whenever the investment cost exceeds the expected net cash flow stream after considering the impact of market conditions. [less ▲]

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See detailTargeted advertising and consumer information
Broos, Sébastien ULiege

E-print/Working paper (2017)

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See detailDecidable properties of extension graphs for substitutive languages
Dolce, Francesco; Kyriakoglou, Revekka; Leroy, Julien ULiege

E-print/Working paper (2017)

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See detailFully leafed induced subtrees
Blondin Massé, Alexandre; de Carufel, Julien; Goupil, Alain et al

E-print/Working paper (2017)

Let G be a simple graph of n vertices. We consider the problem ISil of deciding whether there exists an induced subtree with exactly i ≤ n vertices and l leaves in G. We also study the associated ... [more ▼]

Let G be a simple graph of n vertices. We consider the problem ISil of deciding whether there exists an induced subtree with exactly i ≤ n vertices and l leaves in G. We also study the associated optimization problem, that consists in computing the maximal number of leaves, denoted by L_G(i), realized by an induced subtree with i vertices, for 2 ≤ i ≤ n. We compute the values of the map L_G for some classical families of graphs and in particular for the d-dimensional hypercubic graphs Q_d , d ≤ 6. Then we prove that the ISil problem is in general NP-complete. We also describe a nontrivial branch and bound algorithm that computes the function L_G for any simple graph G. In the special case where G is a tree, we provide a O(δn^3) time and O(n^2) space algorithm, where δ is the maximum degree of G. Finally, we exhibit a bijection between the set of discrete derivative of the sequences L_G (i) where G is caterpillar, and the set of prefix normal words. [less ▲]

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See detailAdaptive large neighborhood search for multi-trip vehicle routing with time windows
François, Véronique ULiege; Arda, Yasemin ULiege; Crama, Yves ULiege

E-print/Working paper (2017)

We consider a multi-trip vehicle routing problem with time windows (MTVRPTW), in which each vehicle can perform several trips during its working shift. This problem is especially relevant in the context ... [more ▼]

We consider a multi-trip vehicle routing problem with time windows (MTVRPTW), in which each vehicle can perform several trips during its working shift. This problem is especially relevant in the context of city logistics. Heuristic solution methods for multi-trip vehicle routing problems often separate routing and assignment phases in order to create trips and then assign them to the available vehicles. We show that this approach is outperformed by an integrated solution method in the presence of time windows. We use an automatic configuration tool to obtain efficient and contextualized implementations of our solution methods. We provide suitable instances for the MTVRPTW as well as an instance generator. Also, we discuss the relevance of two objective functions: the total duration and the total travel time. When minimizing the travel time, large increases of waiting time are incurred, which is not realistic in practice. [less ▲]

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See detailDifferent possible behaviors of wavelet leaders of the Brownian motion
Ayache, Antoine; Esser, Céline ULiege; Kleyntssens, Thomas ULiege

E-print/Working paper (2017)

The aim of this paper is to prove that wavelet leaders allow to get very fine properties of the trajectories of the Brownian motion: more precisely, we show that there exist (at least) three different ... [more ▼]

The aim of this paper is to prove that wavelet leaders allow to get very fine properties of the trajectories of the Brownian motion: more precisely, we show that there exist (at least) three different behaviors for the size of wavelet leaders of the Brownian motion. Furthermore, they correspond to the three well-known behaviors of its oscillations, namely to be ordinary, rapid and slow. Some links between the oscillations and the size of wavelet leaders at a given point are also given. [less ▲]

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See detailLineability in multifractal analysis
Esser, Céline ULiege; Jaffard, Stéphane ULiege

E-print/Working paper (2017)

The multifractal behavior of generic functions belonging to H older, Sobolev or Besov spaces has been investigated by many authors, using the concepts of Baire residuality and of prevalence. This paper ... [more ▼]

The multifractal behavior of generic functions belonging to H older, Sobolev or Besov spaces has been investigated by many authors, using the concepts of Baire residuality and of prevalence. This paper aims at obtaining the corresponding results in the framework supplied by the notion of lineability. Furthermore, we also study the question of algebrability, proving negative and positive results. [less ▲]

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See detailLa satisfaction des conditions de travail des médecins comme facteur déterminant des réussites médicales
Bounazef, Djida ULiege; Van Caillie, Didier ULiege

E-print/Working paper (2017)

Quality of workplace health and safety conditions of medical doctors has a strategic role in their availability for patients’ care, risk reduction of medical errors and rate of medical successes. The ... [more ▼]

Quality of workplace health and safety conditions of medical doctors has a strategic role in their availability for patients’ care, risk reduction of medical errors and rate of medical successes. The improvement of these conditions represents an opportunity of internal improvement that optimizes better medical services. The case study examines the quality of workplace health and safety conditions of 200 medical doctors belonging to different Algerian UHCs. It analyses its correlation with the daily time devoted to the care of patients, with the rate of risk reduction of medical errors, and with the rate of medical successes. Multiple regression analyses the interaction effect of the three first variables on the rate of medical successes. Results determine a strong causal factor between medical doctors’ availability – quality of workplace conditions and medical successes. Results also highlight a strong correlation between quality of workplace conditions and risk reduction of medical errors. [less ▲]

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See detailPotential, opportunities and benefits of electric vehicles as frequency regulation resources
Glavic, Mevludin ULiege; 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 detailStatus and Coordination in Organizations
Lam, Wing Man Wynne ULiege

E-print/Working paper (2016)

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See detailLe compromis entre culture non punitive et culture juste : analyse des sous-cultures de sécurité des patients dans un service de radiothérapie
Kamto Kenmogne, Marius ULiege; Van Caillie, Didier ULiege; BOGA, Deniz ULiege et al

E-print/Working paper (2016)

The recent publication of the report "Medical error-the third leading causes of death in the US" (Makary & Daniel, 2016) has led to a renewed attention to the issue of patient safety in many developed ... [more ▼]

The recent publication of the report "Medical error-the third leading causes of death in the US" (Makary & Daniel, 2016) has led to a renewed attention to the issue of patient safety in many developed countries. The main issue involved is the role played by medical staff work in the occurrence of deaths from the medical care. According to Makary & Daniel, communication failures, misdiagnosis, bad judgments and inadequate skills have caused an average of 251,454 deaths per year in the United States in 2013. This report has taken the opposite view of the proponents of "No shame no blame" approach characterizing a non-punitive culture in which people are led to blame the system even though human responsibility is obvious. While the no-blame culture has often been presented as the success factor of an efficient safety /quality policy in medical settings (Amalberti et al., 2005; Woynar et al, 2007), discordant voices now stand to underline the limits of this approach (see eg Dekker & Breakey, 2016; Levitt, 2014 or Shojania & Dixon-Woods, 2013). These authors argue that the no-blame culture is difficult to implement in practice and suggest the implementation of a just culture that places more emphasis on individuals' behavior and performance and on their responsibility at work. In this context, this study examines – based on an in-depth longitudinal case study of a radiotherapy department that has implemented a reporting system for adverse events - the extent to which non-punitive culture and just culture can live together in the same organizational unit. By combining in-depth interviews with members of the quality team and a questionnaire survey administered to all staff, we evaluate the current safety subcultures in the service. The content analysis of the interviews and the treatment of questionnaires following the methodology of the Agency for Healthcare Research and Quality allows to see the emergence of three subcultures in the radiotherapy department studied: a reporting subculture, a non-punitive subculture and, to some extent, a just subculture. The study shows that the development of the safety culture in this department is based primarily on the establishment of a non-punitive subculture used as a way to encourage spontaneous reporting of adverse events. The reporting culture is therefore the more controlled dimension of the safety culture of the department. Concerning responsibility of workers, the study shows that they have no fear of punishment and are not even familiar with the term in the workplace. On the contrary, instead of a retributive just culture, the department has focused its safety culture on learning from mistakes and substantial just culture based on a system of worker participation in the preparation of procedures that prescribe the right way to work. [less ▲]

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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 ULiege; 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 np- Control Charts with the Guaranteed In-Control Performance
Faraz, Alireza ULiege; Heuchenne, Cédric ULiege

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

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 ULiege

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 detailNouvelles normes sylvicoles pour les peuplements purs équiennes d'épicéa et de douglas
Perin, Jérôme ULiege; Hebert, Jacques ULiege; Lejeune, Philippe ULiege 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 detailEarly Detection of University Students in Potential Difficulty
Hoffait, Anne-Sophie ULiege; Schyns, Michael ULiege

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

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

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

E-print/Working paper (2016)

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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 ULiege

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

E-print/Working paper (2016)

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 detailSéminaire "Storytelling": note d'intention
Claisse, Frédéric ULiege; Huppe, Justine ULiege

E-print/Working paper (2016)

A l'origine, cette note constitue un document de travail à destination des étudiant-e-s de Masters en langues et lettres françaises romanes, à finalité approfondie, qui ont choisi le module « Storytelling ... [more ▼]

A l'origine, cette note constitue un document de travail à destination des étudiant-e-s de Masters en langues et lettres françaises romanes, à finalité approfondie, qui ont choisi le module « Storytelling » dans le cadre du séminaire de littérature (XIXe-XXIe) : Histoire, société, institutions, discours (2e quadrimestre, année 2015-2016). Elle reprend les hypothèses et grandes lignes du projet de recherche (FRS-FNRS) "Storyfic", qui vise à évaluer l'impact du storytelling sur l'écriture de fiction contemporaine. [less ▲]

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See detailMarket efficiency and hedge fund trading strategies
Lambert, Marie ULiege; Papapeorgiou, Nicolas; Platania, Federico

E-print/Working paper (2016)

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

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 ULiege; Wehenkel, Louis ULiege; Louveaux, Quentin ULiege

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 ULiege; Bodu, Pierre; Geurten, Stéphanie et al

E-print/Working paper (2016)

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

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 ULiege; Vanrykel, Fanny ULiege; Defoy, Xavier ULiege

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 ULiege; Köppe, Matthias; Louveaux, Quentin ULiege

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

E-print/Working paper (2016)

Detailed reference viewed: 50 (6 ULiège)