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See detailLearning to play K-armed bandit problems
Maes, Francis ULg; Wehenkel, Louis ULg; Ernst, Damien ULg

in Proceedings of the 4th International Conference on Agents and Artificial Intelligence (ICAART 2012) (2012, February)

We propose a learning approach to pre-compute K-armed bandit playing policies by exploiting prior information describing the class of problems targeted by the player. Our algorithm first samples a set of K ... [more ▼]

We propose a learning approach to pre-compute K-armed bandit playing policies by exploiting prior information describing the class of problems targeted by the player. Our algorithm first samples a set of K-armed bandit problems from the given prior, and then chooses in a space of candidate policies one that gives the best average performances over these problems. The candidate policies use an index for ranking the arms and pick at each play the arm with the highest index; the index for each arm is computed in the form of a linear combination of features describing the history of plays (e.g., number of draws, average reward, variance of rewards and higher order moments), and an estimation of distribution algorithm is used to determine its optimal parameters in the form of feature weights. We carry out simulations in the case where the prior assumes a fixed number of Bernoulli arms, a fixed horizon, and uniformly distributed parameters of the Bernoulli arms. These simulations show that learned strategies perform very well with respect to several other strategies previously proposed in the literature (UCB1, UCB2, UCB-V, KL-UCB and $\epsilon_n$-GREEDY); they also highlight the robustness of these strategies with respect to wrong prior information. [less ▲]

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See detailDoes pupil constriction under blue and green monochromatic light exposure change with age?
Daneault, V; Vandewalle, Gilles ULg; Hébert, M et al

Poster (2012, February)

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See detailDifferential proteomic analysis of a human breast tumor and its matched bone metastasis identifies cell membrane and extracellular proteins associated with bone metastasis
Dumont, Bruno ULg; Castronovo, Vincenzo ULg; Peulen, Olivier ULg et al

in Journal of Proteome Research (2012)

The classical fate of metastasizing breast cancer cells is to seed and form secondary colonies in bones. The molecules closely associated with these processes are predominantly present at the cell surface ... [more ▼]

The classical fate of metastasizing breast cancer cells is to seed and form secondary colonies in bones. The molecules closely associated with these processes are predominantly present at the cell surface and in the extracellular space, establishing the first contacts with the target tissue. In this study, we had the rare opportunity to analyze a bone metastatic lesion and its corresponding breast primary tumor obtained simultaneously from the same patient. Using mass spectrometry, we undertook a proteomic study on cell surface and extracellular protein-enriched material. We provide a repertoire of significantly modulated proteins, some with yet unknown roles in the bone metastatic process as well as proteins notably involved in cancer cell invasiveness and in bone metabolism. The comparison of these clinical data with those previously obtained using a human osteotropic breast cancer cell line highlighted an overlapping group of proteins. Certain differentially expressed proteins are validated in the present study using immunohistochemistry on a retrospective collection of breast tumors and matched bone metastases. Our exclusive set of selected proteins supports the set-up of further investigations on both clinical samples and experimental bone metastasis models that will help to reveal the finely coordinated expression of proteins that favor the development of metastases in the bone microenvironment. [less ▲]

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See detailMicroorganisms from aphid honeydew attract natural enemies and tending ants
Verheggen, François ULg; Leroy, Pascal; Fischer, Christophe ULg et al

Conference (2012, February)

Aphids are some of the most serious pests of cultivated crops worldwide, causing major yield and economic losses. Previous works have demonstrated ants and natural enemies (including ladybeetles and ... [more ▼]

Aphids are some of the most serious pests of cultivated crops worldwide, causing major yield and economic losses. Previous works have demonstrated ants and natural enemies (including ladybeetles and hoverflies) to be able to use aphid volatile chemicals to locate aphid colonies. Here, we report the first isolation of a bacterium from the pea aphid Acyrthosiphon pisum honeydew, Staphylococcus sciuri, which produces kairomones used by the aphidophagous hoverfly Episyrphus balteatus and the Asian Ladybeetle Harmonia axyridis during their search for prey colonies. Some specific semiochemicals produced by S. sciuri were identified as attractants and ovipositional stimulants. Similarly, we have shown scouts of the aphid tending ant species, Lasius niger, to orientate their foraging behaviour toward an Aphis fabae infested plant and we have demonstrated that the odours released by this aphid honeydew were attractive for ant scouts. Again, bacteria were involved in the production of these honeydew semiochemicals. Interestingly, ant scouts were also able to discriminate honeydew odour from A. fabae (usually attended by L. niger) and A. pisum (unattendedby L. niger). Comparison of the volatile and bacteria composition of both aphid species honeydew were attended. [less ▲]

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See detailFrançois Jacqmin, entre l'ascèse et la tempête
Purnelle, Gérald ULg

Article for general public (2012)

François Jacqmin compte parmi les quelques deux ou trois plus grands poètes de Belgique. Toute l’écriture de celui qui a dit « la poésie sera consolatrice, ou rien » est une lutte contre les limites ou ... [more ▼]

François Jacqmin compte parmi les quelques deux ou trois plus grands poètes de Belgique. Toute l’écriture de celui qui a dit « la poésie sera consolatrice, ou rien » est une lutte contre les limites ou les illusions de la pensée et de la parole, une tentative de dépasser l’impuissance de la poésie à conserver trace de l’émerveillement de l’homme devant la nature. Réel et langage, désir et nihilisme sont les pôles d’une œuvre capitale. [less ▲]

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See detailDaljit Nagra: Sourires de tigre et dents brunes
Munos, Delphine ULg

Article for general public (2012)

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See detailQUALITY BY DESIGN COMPLIANT METHOD VALIDATION
Rozet, Eric ULg; Boulanger, B.; Hubert, Philippe ULg

Poster (2012, February)

Analytical method validation is a mandatory step to evaluate the ability of developed methods to provide accurate results for their routine application in order to trust the critical decisions that will ... [more ▼]

Analytical method validation is a mandatory step to evaluate the ability of developed methods to provide accurate results for their routine application in order to trust the critical decisions that will be made with them. Even if several guidelines exist to help perform analytical method validations (ICH Q2R1 [1], USP <1225> [2], …) there is still the need to clarify the meaning and interpretation of analytical method validation criteria and methodology. Indeed, actually method validation is mostly realised as the traditional check list implementation of e.g. the ICH Q2R1 or USP <1225> method validation requirements. However, within the trend of Quality by Design [3], there is the need to switch from this traditional vision to an analytical method validation really adding value and providing a high level of assurance of analytical methods results reliability. Yet, different interpretations can be made of the validation guidelines as well as for the definitions of the validation criteria. This will lead to diverse experimental designs implemented to try fulfilling these criteria. Finally, different decision methodologies can also be interpreted from these guidelines. Therefore, the risk that a validated analytical method may be unfit for its future purpose will depend on a personal interpretation of these guidelines. The objective of this presentation is thus to show that analytical method validation should be planned and performed by first starting with the end in mind: what is the objective of the analytical methods under study? In such a way analytical method validation is coherent with the actual Quality by Design regulatory expectations. The risk of having validated an analytical method unfit for its purpose is strongly reduced as well as the risk of generating Out of Specification (OOS) results due to an unfit method. References [1] International Conference on Harmonisation (ICH) of Technical Requirements for registration of Pharmaceuticals for Human Use, Topic Q2 (R1): Validation of Analytical Procedures: Text and Methodology, Geneva, 2005. [2] USP 33 NF 28 S1, U.S. Pharmacopeia, 2007. USP–NF General Chapter <1225>. [3] International Conference on Harmonisation (ICH) of Technical Requirements for Registration of Pharmaceuticals for Human Use, Topic Q8(R2): Pharmaceutical development, Geneva, 2009. [less ▲]

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See detailEddy Currents and Corner Singularities
Buret, François; Dauge, Monique; Dular, Patrick ULg et al

in IEEE Transactions on Magnetics (2012), 48(2), 679-682

Eddy current problems are addressed in a bidimensional setting where the conducting medium is non-magnetic and has a corner singularity. For any fixed parameter linked to the skin depth for a plane ... [more ▼]

Eddy current problems are addressed in a bidimensional setting where the conducting medium is non-magnetic and has a corner singularity. For any fixed parameter linked to the skin depth for a plane interface, we show that the flux density is bounded near the corner unlike the perfect conducting case. Then as goes to zero, the first two terms of a multiscale expansion of the magnetic potential are introduced to tackle the magneto-harmonic problem. The heuristics of the method are given and numerical computations illustrate the obtained accuracy. [less ▲]

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See detailRapport 2 FIRST Spin Off IMONIC
Goffin, Dorothée ULg

Report (2012)

Rapport du projet FIRST spin-off IMONIC financé par le SPW (Production de mélanges à valeur santé contenant des isomaltooligosaccharides et de l’acide gluconique prébiotiques et répondant au cahier des ... [more ▼]

Rapport du projet FIRST spin-off IMONIC financé par le SPW (Production de mélanges à valeur santé contenant des isomaltooligosaccharides et de l’acide gluconique prébiotiques et répondant au cahier des charges de l’agriculture biologique). [less ▲]

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See detailRutherford backscattering analysis of porous thin TiO2 films
Mayer, Matej; von Toussaint, Udo; Dewalque, Jennifer ULg et al

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (2012), 273

The additional energy spread due to sample porosity was implemented in the SIMNRA simulation code, version 6.60 and higher. Deviations of the path length and energy loss distributions from the ones ... [more ▼]

The additional energy spread due to sample porosity was implemented in the SIMNRA simulation code, version 6.60 and higher. Deviations of the path length and energy loss distributions from the ones expected from a Poisson distribution of the number of traversed pores are taken into account. These deviations are due to the interaction of pores at higher pore concentrations by overlap or blocking. The skewnesses of the energy distributions are approximated by two-piece normal distributions with identical first three moments. Propagation of porosity-induced energy spread in thick layers is taken into account. Calculated results are compared to experimental data obtained with thin TiO2 mesoporous films measured by Rutherford backscattering (RBS),transmission electron microscopy (TEM), and atmospheric poroellipsometry. [less ▲]

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See detailPPP et sociologie de la confiance : présentation des premiers résultats
Remy, Céline ULg

Scientific conference (2012, January 31)

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See detailLa relation professionnelle : l'expérience de la logopédie
Maillart, Christelle ULg

Scientific conference (2012, January 31)

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See detailLa réforme institutionnelle et le nouvel accord gouvernemental
Verjans, Pierre ULg

Conference given outside the academic context (2012)

Le contenu de l'accord gouvernemental négocié après plus d'un an et demi de crise gouvernementale, les partenaires ont convenu de modifier les institutions belges et d'adopter une politique socio ... [more ▼]

Le contenu de l'accord gouvernemental négocié après plus d'un an et demi de crise gouvernementale, les partenaires ont convenu de modifier les institutions belges et d'adopter une politique socio-économique rigoureuse pour faire face à la crise financière internationale. [less ▲]

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See detailRapport de l'atelier "Compétences et Learning Outcomes : quelles convergences?"
Cormann, Grégory ULg

Diverse speeche and writing (2012)

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See detailAccompagner les futurs logopèdes dans le travail de la langue française
Maillart, Christelle ULg; Jacquet, Maud ULg

Scientific conference (2012, January 31)

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