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See detailPhase resolved X-ray spectroscopy of HDE 288766: Probing the wind of an extreme Of+/WNLha star
Rauw, Grégor ULg; Mahy, Laurent; Nazé, Yaël ULg et al

in Astronomy and Astrophysics (2014), 566

Context. HDE 228766 is a very massive binary system hosting a secondary component, which is probably in an intermediate evolutionary stage between an Of supergiant and an WN star. The wind of this star ... [more ▼]

Context. HDE 228766 is a very massive binary system hosting a secondary component, which is probably in an intermediate evolutionary stage between an Of supergiant and an WN star. The wind of this star collides with the wind of its O8 II companion, leading to relatively strong X-ray emission. <BR /> Aims: Measuring the orbital variations of the line-of-sight absorption toward the X-ray emission from the wind-wind interaction zone yields information on the wind densities of both stars. <BR /> Methods: X-ray spectra have been collected at three key orbital phases to probe the winds of both stars. Optical photometry has been gathered to set constraints on the orbital inclination of the system. <BR /> Results: The X-ray spectra reveal prominent variations of the intervening column density toward the X-ray emission zone, which are in line with the expectations for a wind-wind collision. We use a toy model to set constraints on the stellar wind parameters by attempting to reproduce the observed variations of the relative fluxes and wind optical depths at 1 keV. <BR /> Conclusions: The lack of strong optical eclipses sets an upper limit of ~ 68° on the orbital inclination. The analysis of the variations of the X-ray spectra suggests an inclination in the range 54-61° and indicates that the secondary wind momentum ratio exceeds that of the primary by at least a factor 5. Our models further suggest that the bulk of the X-ray emission arises from the innermost region of the wind interaction zone, which is from a region whose outer radius, as measured from the secondary star, lies between 0.5 and 1.5 times the orbital separation. Based on observations collected with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA member states and the USA (NASA), and on data collected at the San Pedro Mártir observatory (Mexico). [less ▲]

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See detailThe four duties of family doctors. Quaternary prevention: First, do no harm
Jamoulle, Marc ULg

in Hong Kong Practitioner (2014), 36

Cl inical prevent ion has been organised in a chronological manner since the middle of the 20th century. A paradigm shift from a chronological to a relationship-based preventive pattern of care offers new ... [more ▼]

Cl inical prevent ion has been organised in a chronological manner since the middle of the 20th century. A paradigm shift from a chronological to a relationship-based preventive pattern of care offers new insight into the practice of doctors, and brings to light the concept of quaternary prevention, a critical look at medical activities with an emphasis on the need not to harm. Quaternary prevention addresses the fundamental question of what constitutes too much or too little medicine. It is the fourth form of disease prevention, but also the fourth frame of action for family doctors. New definitions of prevention published in the Wonca Dictionary of Family Medicine offer a structured way to discuss the activities of family doctors, including ethical considerations on the patient-doctor encounter. 摘要 [less ▲]

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See detailEvaluation of the Economic Statistical Design of the Multivariate T2 Control Chart with Multiple Variable Sampling Intervals Scheme: NSGA-II Approach
Faraz, Alireza ULg; Seif, Asghar; Sadeghifar

in Journal of Statistical Computation & Simulation (2014)

The economic and statistical merits of a multiple variable sampling intervals (MVSI) scheme are studied. The problem is formulated as a double-objective optimization problem with the adjusted average time ... [more ▼]

The economic and statistical merits of a multiple variable sampling intervals (MVSI) scheme are studied. The problem is formulated as a double-objective optimization problem with the adjusted average time to signal as the statistical objective and the expected cost per hour as the economic objective. Bai and Lee’s ‎[2] economic model is considered. Then we find the Pareto-optimal designs in which the two objectives are minimized simultaneously by using the non-dominated sorting genetic algorithm. Through an illustrative example, the advantages of the proposed approach is shown by providing a list of viable optimal solutions and graphical representations, which indicate the advantage of flexibility and adaptability of our approach. [less ▲]

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See detailSpondylolysis with or without spondylolisthesis
Gillet, Philippe ULg

in Bentley, George (Ed.) European surgical orthopaedics and traumatology, The EFORT Textbook (2014)

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See detailComputational homogenization of cellular materials
Nguyen, Van Dung ULg; Noels, Ludovic ULg

in International Journal of Solids and Structures (2014), 51(11-12), 2183-2203

In this work we propose to study the behavior of cellular materials using a second–order multi–scale computational homogenization approach. During the macroscopic loading, micro-buckling of thin ... [more ▼]

In this work we propose to study the behavior of cellular materials using a second–order multi–scale computational homogenization approach. During the macroscopic loading, micro-buckling of thin components, such as cell walls or cell struts, can occur. Even if the behavior of the materials of which the micro–structure is made remains elliptic, the homogenized behavior can lose its ellipticity. In that case, a localization band is formed and propagates at the macro–scale. When the localization occurs, the assumption of local action in the standard approach, for which the stress state on a material point depends only on the strain state at that point, is no–longer suitable, which motivates the use of the second-order multi–scale computational homogenization scheme. At the macro–scale of this scheme, the discontinuous Galerkin method is chosen to solve the Mindlin strain gradient continuum. At the microscopic scale, the classical finite element resolutions of representative volume elements are considered. Since the meshes generated from cellular materials exhibit voids on the boundaries and are not conforming in general, the periodic boundary conditions are reformulated and are enforced by a polynomial interpolation method. With the presence of instability phenomena at both scales, the arc–length path following technique is adopted to solve both macroscopic and microscopic problems. [less ▲]

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See detailAquifères de l'Ardenne
Debbaut, Vincent ULg; Cajot, Odette; Ruthy, Ingrid ULg et al

in Dassargues, Alain; Walraevens, Kristine (Eds.) Watervoerende lagen & grondwater in België - Aquifères & eaux souterraines en Belgique (2014)

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See detailArrival of european eel in Belgian Part of the Meuse: who and how are they?
Nzau Matondo, Billy ULg; Benitez, Jean-Philippe ULg; Dierckx, Arnaud ULg et al

in Proceedings of the 10th International Conference on Ecohydraulics (2014, June)

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See detailSimple connectome inference from partial correlation statistics in calcium imaging
Sutera, Antonio ULg; Joly, Arnaud ULg; François-Lavet, Vincent ULg et al

in Proceedings of Connectomics 2014 (ECML 2014) (2014, June)

In this work, we propose a simple yet effective solution to the problem of connectome inference in calcium imaging data. The proposed algorithm consists of two steps. First, processing the raw signals to ... [more ▼]

In this work, we propose a simple yet effective solution to the problem of connectome inference in calcium imaging data. The proposed algorithm consists of two steps. First, processing the raw signals to detect neural peak activities. Second, inferring the degree of association between neurons from partial correlation statistics. This paper summarises the methodology that led us to win the Connectomics Challenge, proposes a simplified version of our method, and finally compares our results with respect to other inference methods. [less ▲]

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See detailPhilosophy of economic security of organization: The constructivist approach
Shutyak, Yuliya ULg

Conference (2014, June)

The purpose of this paper is to present the concept of economic security of the organization. Guiding by the constructivism approach, the author conducts a narrative literature review on economic security ... [more ▼]

The purpose of this paper is to present the concept of economic security of the organization. Guiding by the constructivism approach, the author conducts a narrative literature review on economic security of organization in parallel with well-known theories of business management.The presented in the paper ideas are an impulse for a new wave in organizational research basing on a new globalizing theoretical framework. The proposed approach to organizational management through the prism of security allows connecting disjoined concepts used in organizational studies and highlights aspects important for organizational survival and growth but mostly overlooked by scientists. The paper’s value consists in evolving of a relatively unexploited concept of economic security of the organization. [less ▲]

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See detailDouble Sweep Preconditioners for propagation problems solved by Optimized Schwarz Methods
Vion, Alexandre ULg; Geuzaine, Christophe ULg

in Proceedings of the 6th International Conference on Advanced COmputational Methods in ENgineering, ACOMEN 2014 (2014, June)

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See detailLe Portrait photographique d'écrivain
Bertrand, Jean-Pierre ULg; Durand, Pascal ULg; Lavaud, Martine

in COnTEXTES : Revue de Sociologie de la Littérature (2014), 14

Il en va des phénomènes omniprésents comme des évidences : ils passent volontiers inaperçus quand ils ne sont pas reçus comme procédant d’une nature des choses plutôt que d’une émergence historique et ... [more ▼]

Il en va des phénomènes omniprésents comme des évidences : ils passent volontiers inaperçus quand ils ne sont pas reçus comme procédant d’une nature des choses plutôt que d’une émergence historique et sociale. Vitrines de libraires, quatrièmes de couverture, affiches publicitaires, catalogues d’éditeur, manuels scolaires, monographies illustrées, journaux, magazines, émissions de télévision, documentaires, vidéos continuent d’enfoncer jour après jour dans notre œil l’évidence aveuglante que l’écrivain a un visage. Il n’en a pas toujours été ainsi et c’est bien en s’en avisant que l’on peut se mettre en condition de prendre la mesure des effets que la photographie, après d’autres formes de représentation iconographique, puis en concurrence avec celles-ci, a exercés non seulement sur la mise en image de la littérature et la visibilité de ceux qui la produisent, mais encore sur leur commune définition sociale après 1840. C’est dans cet esprit général, sensible aux modalités matérielles de l’histoire des représentations ainsi qu’aux implications épistémologiques du portrait photographique d’écrivain, que s’inscrivent les contributions réunies à l’enseigne de la revue Contextes. Elles proviennent de deux journées d’études qui se sont tenues à l’Université de Liège les 6 et 7 juin 2013 en vue d’éclairer sous différents aspects l’histoire des formes, des supports et des usages du portrait photographique d’écrivain de la fin des années 1830 à l’époque contemporaine — du romantisme au Nouveau Roman ou encore de Balzac à Houellebecq. Conformément à l’objet étudié, l’approche développée se veut résolument transdisciplinaire. Historiens de l’art et de la photographie rappellent utilement les conditions de naissance et de développement exponentiel d’un genre ayant bousculé l’ordre des représentations et les esthétiques. Historiens et sociologues de la littérature font ressortir les liens établis entre portrait photographique et auteurs photographiés, avec les implications que le médium a occasionnées durablement dans l’imaginaire littéraire. Sémioticiens et spécialistes des sciences du langage mettent en œuvre leur outillage descriptif sur la matérialité et la discursivité du cliché. Avec cela de commun en ligne de mire : à quoi tient la littérarité d’un portrait photographique d’écrivain ? A cette question, le dossier apporte quelques éléments de réponse en proposant un recadrage et un décadrage. Recadrage de l’image elle-même au sein des configurations auxquelles elle participe. Décadrage du portrait en direction des effets de contexte et de support qui sont inducteurs de sa signification. SOMMAIRE Martine LAVAUD (Paris IV), « Envisager l’histoire littéraire. Pour une épistémologie du portrait photographique d’écrivain » Pascal DURAND (ULg), « De Nadar à Dornac. Hexis corporelle et figuration photographique des écrivains » Jean-Pierre BERTRAND (ULg), « Esquisse d’un protocole de lecture du portrait photographique d’écrivain » Marc-Emmanuel MÉLON (ULg), Portrait de l’écrivain absorbé. Une allégorie photographique » Adeline WRONA (Celsa, Université Paris Sorbonne), « Le portrait-carte, de la photographie au journal. Le marché périodique du portrait d’écrivain » Hélène VÉDRINE (Université Paris Sorbonne), « Portraits de masques et de fantômes. Le portrait photographique dans le livre (1860-1930) » Bernard VOUILLOUX (Université Paris Sorbonne), « Une collection d’unica : les livres à portraits d’Edmond de Goncourt » François PROVENZANO (ULg), « Portrait photographique d’écrivain et newsmagazine. Pour une approche rhétorique de l’événementialité du littéraire » Fanny LORENT (ULg), « Portrait et imaginaire photographique. Cliché et anti-cliché du Nouveau Roman » Maria Giulia DONDERO (FNRS/ULg), « Les approches sémiotiques du portrait photographique. De l’identité à l’“air” » Jérôme MEIZOZ (Université de Lausanne), « Portrait photographique et présentation de soi. Cendrars, Houellebecq » [less ▲]

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See detailLes eaux minérales et thermales en Wallonie : les eaux minérales de Valvert
Bouezmarni, Mohamed ULg; Debbaut, Vincent ULg; Naa, Paul

in Dassargues, Alain; Walraevens, Kristine (Eds.) Watervoerende lagen & grondwater in België - Aquifères & eaux souterraines (2014)

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See detailComparison of centralized, distributed and hierarchical model predictive control schemes for electromechanical oscillations damping in large-scale power systems
Wang, Da ULg; Glavic, Mevludin ULg; Wehenkel, Louis ULg

in International Journal of Electrical Power & Energy Systems (2014), 58

The paper investigates the feasibility of applying Model Predictive Control (MPC) as a viable strategy to damp wide-area electromechanical oscillations in large-scale power systems. First a fully ... [more ▼]

The paper investigates the feasibility of applying Model Predictive Control (MPC) as a viable strategy to damp wide-area electromechanical oscillations in large-scale power systems. First a fully centralized MPC scheme is considered, and its performances are evaluated first in ideal conditions and then by considering state estimation errors and communication delays. This scheme is further extended into a distributed scheme with the aim of making it more viable for very large-scale or multi-area systems. Finally, a robust hierarchical multi-area MPC scheme is proposed, introducing a second layer of MPC based controllers at the level of individual power plants and transmission lines. Simulations are carried out using a 70-bus test system. The results reveal all three MPC schemes as viable solutions to supplement existing controllers in order to improve the system performance in terms of damping. The hierarchical scheme is the one combining the best performances in nominal conditions and the best robustness with respect to partial component failures and various modeling and measurement errors. [less ▲]

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See detailOn the Quality of BGP Route Collectors for iBGP Policy Inference
Cittadini, Luca; Vissicchio, Stefano; Donnet, Benoît ULg

in IFIP Networking (2014, June)

A significant portion of what is known about Internet routing stems out from public BGP datasets. For this reason, numerous research efforts were devoted to (i) assessing the (in)completeness of the ... [more ▼]

A significant portion of what is known about Internet routing stems out from public BGP datasets. For this reason, numerous research efforts were devoted to (i) assessing the (in)completeness of the datasets, (ii) identifying biases in the dataset, and (iii) augmenting data quality by optimally placing new collectors. However, those studies focused on techniques to extract information about the AS-level Internet topology. In this paper, we show that considering different metrics influences the conclusions about biases and collector placement. Namely, we compare AS-level topology discovery with \iac inference. We find that the same datasets exhibit significantly diverse biases for these two metrics. For example, the sensitivity to the number and position of collectors is noticeably different. Moreover, for both metrics, the marginal utility of adding a new collector is strongly localized with respect to the proximity of the collector. Our results suggest that the ``optimal'' position for new collectors can only be defined with respect to a specific metric, hence posing a fundamental trade-off for maximizing the utility of extensions to the BGP data collection infrastructure. [less ▲]

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See detailOn the Performance of the LISP Beta Network
Coras, Florin; Saucez, Damien; Iannone, Luigi et al

in IFIP Networking (2014, June)

The future Internet has been a hot topic during the past decade and many approaches towards this future Internet, ranging from incremental evolution to complete clean slate ones, have been proposed. One ... [more ▼]

The future Internet has been a hot topic during the past decade and many approaches towards this future Internet, ranging from incremental evolution to complete clean slate ones, have been proposed. One of the proposition, LISP, advocates for the separation of the identifier and the locator roles of IP addresses to reduce BGP churn and BGP table size. Up to now, however, most studies concerning LISP have been theoretical and, in fact, little is known about the actual LISP deployment performance. In this paper, we fill this gap through measurement campaigns carried out on the LISP Beta Network. More precisely, we evaluate the performance of the two key components of the infrastructure: the control plane (i.e., the mapping system) and the interworking mechanism (i.e., communication between LISP and non-LISP sites). Our measurements highlight that performance offered by the LISP interworking infrastructure is strongly dependent on BGP routing policies. If we exclude misconfigured nodes, the mapping system typically provides reliable performance and relatively low median mapping resolution delays. Although the bias is not very important, control plane performance favors USA sites as a result of its larger LISP user base but also because European infrastructure appears to be less reliable. [less ▲]

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See detailCombined uses of supervised classification and Normalized Difference Vegetation Index techniques to monitor land degradation in the Saloum saline estuary system
Dieng, Ndeye Maguette ULg; Dinis, Joel; Faye, Serigne et al

in Diop, Salif; Barusseau, Jean-Paul; Descamp, Cyr (Eds.) The Land/Ocean Interactions in the Coastal Zone of West and Central Africa, Estuaries of the World (2014)

Saltwater contamination constitutes a serious problem in Saloumestuary, due to the intermittent and reverse tide flows of the Saloum River. This phenomenon is caused by the runoff deficit, which forces ... [more ▼]

Saltwater contamination constitutes a serious problem in Saloumestuary, due to the intermittent and reverse tide flows of the Saloum River. This phenomenon is caused by the runoff deficit, which forces the advance of saltwater 60 km upstream, contaminating surface water and thus causing the degradation of biodiversity and large areas of agricultural soils in this region. The present study aims to evaluate the consequences of saltwater contamination in the last three decades in this estuary by assessing the land-cover dynamics. Thus, latter consists of tracking the landscape-changing process over time to identify land-cover transitions. These transitions are closely related to the ecosystem-setting condition and can be used to assess the combined impacts of both natural and human-induced phenomena over a given period of time. In this study, special attention was given to mangrove degradation and to temporal progression of the salty barren soils locally called ‘‘tan’’. The loss of mangrove areas to tan and the general increase in salty barren soil areas can reflect the increase in the level of salinization in the study area over the time period under consideration. To fulfill this objective, four Landsat satellite images from the same season in the years 1984, 1992, 1999, and 2010 were used to infer time series land-use and land-cover maps of the Saloumestuary area. In addition to satellite imagery, rainfall records were used to evaluate climatic variation in terms of high-to-low precipitation during the time span considered. Spectral analysis indicated that from 1984 to 2010, mangroves and savanna/ rain-fed agriculture are converted to ‘‘tan’’ (denuded and salty soils). In addition, these results showed that significant changes in land use/land cover occur within the whole estuary system and reflecting therefore environmental degradation, such as land desertification and salinization, and vegetation degradation which reflect the advanced of salinity [less ▲]

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