![]() Vandereycken, Axel ![]() ![]() ![]() in Entomologie Faunistique (2010), 63(4), 251-258 La lutte contre les pucerons de manière biologique consiste entre autre à utiliser des insectes prédateurs de pucerons tels que les coccinelles. En Belgique un des auxiliaires le plus utilisé est la ... [more ▼] La lutte contre les pucerons de manière biologique consiste entre autre à utiliser des insectes prédateurs de pucerons tels que les coccinelles. En Belgique un des auxiliaires le plus utilisé est la coccinelle à deux points (Adalia bipunctata) mais en 1997, les horticulteurs ont introduit la coccinelle asiatique (Harmonia axyridis) afin de lutter plus efficacement contre les pucerons. Cette coccinelle invasive s'est rapidement répandue dans toute la Belgique et à travers l'Europe. Afin d'évaluer son impact sur l'entomofaune des milieux agricoles, nous avons réalisé un inventaire des aphidiphages présent sur 10 sites réparti en Wallonie. Deux méthodes d'échantillonnage ont été utilisées: (1) l'utilisation de pièges collant et (2) l'observation visuelle dans des quadras d'1m². Après 10 semaines d'inventaire, nous pouvons conclure que pour l'année 2009, la coccinelle asiatique est la coccinelle la plus abondante dans les agro-écosystèmes wallons. Les cultures préférentielles dans lesquelles la coccinelle invasive a été la plus abondante sont la pomme de terre biologique et le maïs. Culture où la quantité de puceron n'est pas forcement la plus élevée. La période de reproduction de la coccinelle asiatique se situe à la mi-juillet, période d'abondance de proies dans les cultures étudiées. [less ▲] Detailed reference viewed: 213 (11 ULiège)![]() Delon, Giles ![]() ![]() ![]() in Chaos (2010) Detailed reference viewed: 72 (19 ULiège)![]() Spinoy, Erik ![]() Article for general public (2010) This a review of the novel De verzwegen Boon (2010) by Flemish author Pol Hoste. Detailed reference viewed: 14 (0 ULiège)![]() Kohl, Benoît ![]() Article for general public (2010) Detailed reference viewed: 32 (1 ULiège)![]() Vrancken, Didier ![]() in SociologieS (2010) Cet article propose de discuter les thèses développées par Danilo Martuccelli dans son ouvrage "La Société singulariste", Paris, Éditions Armand Colin, coll. Individu et société, 2010 Detailed reference viewed: 74 (6 ULiège)![]() Vrancken, Didier ![]() in SociologieS (2010) Dans une récente réédition de l’un de ses ouvrages, Michel Messu revient sur l’enquête qu’il avait menée au cours des années 1980 auprès des assistés sociaux et prolonge son analyse par une réflexion ... [more ▼] Dans une récente réédition de l’un de ses ouvrages, Michel Messu revient sur l’enquête qu’il avait menée au cours des années 1980 auprès des assistés sociaux et prolonge son analyse par une réflexion originale sur les évolutions de la protection sociale actuellement en cours dans la France du XXIe siècle, que l’on pourrait résumer ainsi : la protection sociale se présenterait désormais sous le visage d’une d’assurance d’assistance, garantissant à chaque citoyen une protection qu’il recevra tantôt sous forme d’assurance, tantôt sous forme d’assistance, souvent dans une combinatoire des deux. Cette thèse permet d’insister sur les glissements de registre, voire de régime, d’une protection sociale devenant de plus en plus une protection par intervention sur autrui. Mais, pour l’auteur, elle semble néanmoins pécher par un excès de banalisation du phénomène. S’appuyant sur ses propres analyses, celui-ci propose une vision assez différente de la protection afin d’alimenter le débat [less ▲] Detailed reference viewed: 86 (6 ULiège)![]() Ozer, Pierre ![]() Speech/Talk (2010) Detailed reference viewed: 64 (3 ULiège)![]() in EOS le magazine des sciences (2010), 30(janvier/février 2011), 70-71 Article présentant les recherches effectuées par le Dr Dorothée Goffin dans le domaine des prébiotiques et en particulier des isomaltooligosaccharides Detailed reference viewed: 43 (10 ULiège)![]() Santander, Sébastian ![]() Learning material (2010) Ce document tente de décrypter le processus décisionnel dans le domaine de la politique étrangère. Cette dernière est ici appréhendée au sens large et ne se réduit donc pas aux simples aspects politico ... [more ▼] Ce document tente de décrypter le processus décisionnel dans le domaine de la politique étrangère. Cette dernière est ici appréhendée au sens large et ne se réduit donc pas aux simples aspects politico-sécuritaire. Pour ce faire, on se penche sur l'étude de la politique extérieure de l'Union européene. Durant les années 1990, l'affirmation progressive de l'UE comme acteur international s'effectuera à travers l'émergence et la consolidation de la Politique extérieure et de sécurité commune (PESC), avec les Traités de Maastricht et ensuite d'Amsterdam, avec la Politique européenne commune de sécurité et de défense (PESD) entérinée par le Traité de Nice, ainsi que par le truchement de l'extension des politiques communautaires, et leur projection extérieure correspondante, à tous les domaines de la politique mondiale. L'UE entend désormais exercer une influence dans des secteurs aussi variés que le commerce international, la coopération au développement et la lutte contre la pauvreté, l'environnement et le développement durable, la promotion de la dimension sociale de la globalisation, des droits de l'homme et de la démocratie. Par la même occasion, l'Union s'engage à institutionnaliser des relations avec des pays et des groupements régionaux situés aux quatre coins de la planète ainsi qu'à exercer un rôle au sein d'institutions internationales (OMC,...). A travers cette étude de cas différentes questions sont abordées: de quel niveau institutionnel relève la décision ? Dans quelles conditions est-elle prise ? Est-elle toujours rationnelle ? Quel est le poids des pressions extérieures ? Quels sont les acteurs déterminant? Qui contrôle la décision ? Quels impacts internationaux? [less ▲] Detailed reference viewed: 105 (18 ULiège)![]() Ozer, Pierre ![]() ![]() Scientific conference (2010, December 22) Le Bénin a été affecté par des inondations de grande ampleur durant l'hivernage 2010, affectant plus de 350 000 personnes, causant près de 100 000 sans-abri et tuant à 43 reprises. L'objectif de cette ... [more ▼] Le Bénin a été affecté par des inondations de grande ampleur durant l'hivernage 2010, affectant plus de 350 000 personnes, causant près de 100 000 sans-abri et tuant à 43 reprises. L'objectif de cette recherche est de voir si ces inondations revêtent un caractère exceptionnel ou non du point de vue de l'aléa. Pour ce faire, nous caractérisons les précipitations du réseau synoptique du Bénin sur la période 1940-2009 à partir de différents indices et analysons ensuite l'année 2010. [...] [less ▲] Detailed reference viewed: 329 (36 ULiège)![]() Adam, Stéphane ![]() Diverse speeche and writing (2010) Detailed reference viewed: 48 (1 ULiège)![]() Cornélusse, Bertrand ![]() Doctoral thesis (2010) Our work is driven by a class of practical problems of sequential decision making in the context of electric power generation under uncertainties. These problems are usually treated as receding horizon ... [more ▼] Our work is driven by a class of practical problems of sequential decision making in the context of electric power generation under uncertainties. These problems are usually treated as receding horizon deterministic optimization problems, and/or as scenario-based stochastic programs. Stochastic programming allows to compute a first stage decision that is hedged against the possible futures and -- if a possibility of recourse exists -- this decision can then be particularized to possible future scenarios thanks to the information gathered until the recourse opportunity. Although many decomposition techniques exist, stochastic programming is currently not tractable in the context of day-ahead electric power generation and furthermore does not provide an explicit recourse strategy. The latter observation also makes this approach cumbersome when one wants to evaluate its value on independent scenarios. We propose a supervised learning methodology to learn an explicit recourse strategy for a given generation schedule, from optimal adjustments of the system under simulated perturbed conditions. This methodology may thus be complementary to a stochastic programming based approach. With respect to a receding horizon optimization, it has the advantages of transferring the heavy computation offline, while providing the ability to quickly infer decisions during online exploitation of the generation system. Furthermore the learned strategy can be validated offline on an independent set of scenarios. On a realistic instance of the intra-day electricity generation rescheduling problem, we explain how to generate disturbance scenarios, how to compute adjusted schedules, how to formulate the supervised learning problem to obtain a recourse strategy, how to restore feasibility of the predicted adjustments and how to evaluate the recourse strategy on independent scenarios. We analyze different settings, namely either to predict the detailed adjustment of all the generation units, or to predict more qualitative variables that allow to speed up the adjustment computation procedure by facilitating the ``classical'' optimization problem. Our approach is intrinsically scalable to large-scale generation management problems, and may in principle handle all kinds of uncertainties and practical constraints. Our results show the feasibility of the approach and are also promising in terms of economic efficiency of the resulting strategies. The solutions of the optimization problem of generation (re)scheduling must satisfy many constraints. However, a classical learning algorithm that is (by nature) unaware of the constraints the data is subject to may indeed successfully capture the sensitivity of the solution to the model parameters. This has nevertheless raised our attention on one particular aspect of the relation between machine learning algorithms and optimization algorithms. When we apply a supervised learning algorithm to search in a hypothesis space based on data that satisfies a known set of constraints, can we guarantee that the hypothesis that we select will make predictions that satisfy the constraints? Can we at least benefit from our knowledge of the constraints to eliminate some hypotheses while learning and thus hope that the selected hypothesis has a better generalization error? In the second part of this thesis, where we try to answer these questions, we propose a generic extension of tree-based ensemble methods that allows incorporating incomplete data but also prior knowledge about the problem. The framework is based on a convex optimization problem allowing to regularize a tree-based ensemble model by adjusting either (or both) the labels attached to the leaves of an ensemble of regression trees or the outputs of the observations of the training sample. It allows to incorporate weak additional information in the form of partial information about output labels (like in censored data or semi-supervised learning) or -- more generally -- to cope with observations of varying degree of precision, or strong priors in the form of structural knowledge about the sought model. In addition to enhancing the precision by exploiting information that cannot be used by classical supervised learning algorithms, the proposed approach may be used to produce models which naturally comply with feasibility constraints that must be satisfied in many practical decision making problems, especially in contexts where the output space is of high-dimension and/or structured by invariances, symmetries and other kinds of constraints. [less ▲] Detailed reference viewed: 186 (44 ULiège)![]() ; ; et al Report (2010) Detailed reference viewed: 16 (1 ULiège)![]() Noirhomme, Quentin ![]() ![]() ![]() in Frontiers in Systems Neuroscience (2010), 4 Recent studies in patients with disorders of consciousness (DOC) tend to support the view that awareness is not related to activity in a single brain region but to thalamo-cortical connectivity in the ... [more ▼] Recent studies in patients with disorders of consciousness (DOC) tend to support the view that awareness is not related to activity in a single brain region but to thalamo-cortical connectivity in the frontoparietal network. Functional neuroimaging studies have shown preserved albeit disconnected low-level cortical activation in response to external stimulation in patients in a “vegetative state” or unresponsive wakefulness syndrome. While activation of these “primary” sensory cortices does not necessarily reflect conscious awareness, activation in higher-order associative cortices in minimally conscious state patients seems to herald some residual perceptual awareness. PET studies have identified a metabolic dysfunction in a widespread frontoparietal “global neuronal workspace” in DOC patients including the midline default mode network (“intrinsic” system) and the lateral frontoparietal cortices or “extrinsic system.” Recent studies have investigated the relation of awareness to the functional connectivity within intrinsic and extrinsic networks, and with the thalami in both pathological and pharmacological coma. In brain damaged patients, connectivity in all default network areas was found to be non-linearly correlated with the degree of clinical consciousness impairment, ranging from healthy controls and locked-in syndrome to minimally conscious, vegetative, coma, and brain dead patients. Anesthesia-induced loss of consciousness was also shown to correlate with a global decrease in cortico-cortical and thalamo-cortical connectivity in both intrinsic and extrinsic networks, but not in auditory, or visual networks. In anesthesia, unconsciousness was also associated with a loss of cross-modal interactions between networks. These results suggest that conscious awareness critically depends on the functional integrity of thalamo-cortical and cortico-cortical frontoparietal connectivity within and between “intrinsic” and “extrinsic” brain networks. [less ▲] Detailed reference viewed: 143 (5 ULiège)![]() Defourny, Boris ![]() Doctoral thesis (2010) This thesis investigates the following question: Can supervised learning techniques be successfully used for finding better solutions to multistage stochastic programs? A similar question had already been ... [more ▼] This thesis investigates the following question: Can supervised learning techniques be successfully used for finding better solutions to multistage stochastic programs? A similar question had already been posed in the context of reinforcement learning, and had led to algorithmic and conceptual advances in the field of approximate value function methods over the years. This thesis identifies several ways to exploit the combination "multistage stochastic programming/supervised learning" for sequential decision making under uncertainty. Multistage stochastic programming is essentially the extension of stochastic programming to several recourse stages. After an introduction to multistage stochastic programming and a summary of existing approximation approaches based on scenario trees, this thesis mainly focusses on the use of supervised learning for building decision policies from scenario-tree approximations. Two ways of exploiting learned policies in the context of the practical issues posed by the multistage stochastic programming framework are explored: the fast evaluation of performance guarantees for a given approximation, and the selection of good scenario trees. The computational efficiency of the approach allows novel investigations relative to the construction of scenario trees, from which novel insights, solution approaches and algorithms are derived. For instance, we generate and select scenario trees with random branching structures for problems over large planning horizons. Our experiments on the empirical performances of learned policies, compared to golden-standard policies, suggest that the combination of stochastic programming and machine learning techniques could also constitute a method per se for sequential decision making under uncertainty, inasmuch as learned policies are simple to use, and come with performance guarantees that can actually be quite good. Finally, limitations of approaches that build an explicit model to represent an optimal solution mapping are studied in a simple parametric programming setting, and various insights regarding this issue are obtained. [less ▲] Detailed reference viewed: 181 (18 ULiège)![]() ; ; Delorme, Jérémie ![]() in Buchi, Eva; Schweickard, Wolfgang (Eds.) Dictionnaire Étymologique Roman (DÉRom) (2010) Detailed reference viewed: 20 (0 ULiège)![]() Mahachie John, Jestinah ![]() Conference (2010, December 20) Detailed reference viewed: 22 (3 ULiège)![]() Mottequin, Bernard ![]() in The Palaeontological Association. 54th Annual Meeting. Programme and Abstracts (2010, December 18) Detailed reference viewed: 86 (6 ULiège)![]() Dassargues, Alain ![]() Report (2010) Detailed reference viewed: 11 (0 ULiège)![]() Martiniello, Marco ![]() Scientific conference (2010, December 18) Detailed reference viewed: 11 (0 ULiège) |
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