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See detailOn Reflections and Reflexivity: Unpacking Research Dispositifs
Thoreau, François ULg

in Zülsdorf, Torben; Coenen, Christopher; Ferrari, Arianna (Eds.) et al Quantum Engagements: Social Reflections of Nanoscience and Emerging Technologies (2011)

Abstract. Science and Technology Studies (STS) scholars increasingly engage with science and technology (S&T) practitioners, scientists, engineers, and the like. The actual dynamics of these engagements ... [more ▼]

Abstract. Science and Technology Studies (STS) scholars increasingly engage with science and technology (S&T) practitioners, scientists, engineers, and the like. The actual dynamics of these engagements differ from one project, framework or school to the next. However, to be reflexive, such engagements need at some point to deal with the ambiguous relationship between ‘engager’ and ‘engaged’. In an attempt to disambiguate these interactive ties, this chapter takes inspiration from Vinciane Despret, a philosopher of science who has provided ethnographic studies of ethologists. It specifically draws on two of Despret’s arguments about experiments on animals, more precisely rats, and the paradoxical relationships to which they give rise. By means of analogy, it then illustrates the similar ways in which we, as STS scholars, might happen to frame our interactions with S&T practitioners. It argues that any experimental research dispositif necessarily implies a specific relationship dynamic with whoever is engaged. This should not be considered as an obstacle, but instead an opportunity for learning—yet only if the dispositif is open to protest. The analysis here took shape during an engagement study conducted at a large-scale R&D center in Flanders, Belgium. It is informed by ongoing involvement in a broader research project (STIR) that aims at fostering reflexivity among S&T practitioners. [less ▲]

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See detailOn relative merits of Implicit/Explicit Algorithms for Transient Problems in Metal Forming Simulation
Ponthot, Jean-Philippe ULg; Hogge, Michel ULg

in Proc. of the Int. Conf. on Numerical Methods for Metal Forming in Industry (1994)

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See detailOn Relativistic Scalar and Vector-Mesons with Harmonic Oscillator-Like Interactions
Debergh, N.; Ndimubandi, J.; Strivay, David ULg

in Zeitschrift Fur Physik C-Particles and Fields (1992), 56(3), 421-425

Relativistic descriptions for spin 0 and 1 particles of nonzero restmasses are known for a long time as the so-called Kemmer or Sakata-Taketani formulations. Through harmonic oscillatorlike interactions ... [more ▼]

Relativistic descriptions for spin 0 and 1 particles of nonzero restmasses are known for a long time as the so-called Kemmer or Sakata-Taketani formulations. Through harmonic oscillatorlike interactions, we study the nonrelativistic limit of the corresponding wave equations in connection with expected spin-orbit terms. Typical Foldy-Wouthuysen developments are included in these approaches with exact results up to required orders for interacting vector mesons only. [less ▲]

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See detailOn Sally Ledger and Roger Luckhurst’s The Fin de Siècle: A Reader in Cultural History c.1880-1900
Steyaert, Kris ULg

in Journal of Gender Studies (2002), 11(2), 192-193

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See detail"On se débrouille", or how to be a good judge when the state lets you down?
Andreetta, Sophie ULg; Kolloch, Annalena

Conference (2015, July)

Over the last couple of years, Beninese magistrates have been on strike for months in a row. In 2012, it was about the Ministry of justice implying corruption issues. In 2013, it was about independence ... [more ▼]

Over the last couple of years, Beninese magistrates have been on strike for months in a row. In 2012, it was about the Ministry of justice implying corruption issues. In 2013, it was about independence and fear of political infringement. In 2014, it was about the most recent appointments. When it comes to judges from the bench, most of them complain about their substantial workload, low pay and poor working conditions. They also highlight the discrepancies between the magistrate’s social status and what their families expect from them, the standards of living that people assume that they have. In short, there seems to be a professional malaise within the Beninese bench, who feel like the state is letting them down, yet judges also insist on the importance of their work, and of doing it right. This is why, for the purpose of this paper, we will be looking at the discourses and representations of Beninese judges on their own social and professional status. What does it mean to be a judge in Benin today? Why do young lawyers choose that professional path over other legal careers? How do they ‘do their job right’ and what are the obstacles to it? Considering both age and gender, we are also trying to look at what it means to be a civil servant today, when the state is no longer the only – or the most promising – employer for legal practitioners. [less ▲]

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See detailOn signature-based expressions of system reliability
Marichal, Jean-Luc; Mathonet, Pierre ULg; Waldhauser, Tamás

in Journal of Multivariate Analysis (2011), 102(10), 1410-1416

The concept of signature was introduced by Samaniego for systems whose components have i.i.d. lifetimes. This concept proved to be useful in the analysis of theoretical behaviors of systems. In particular ... [more ▼]

The concept of signature was introduced by Samaniego for systems whose components have i.i.d. lifetimes. This concept proved to be useful in the analysis of theoretical behaviors of systems. In particular, it provides an interesting signature-based representation of the system reliability in terms of reliabilities of k-out-of-n systems. In the non-i.i.d. case, we show that, at any time, this representation still holds true for every coherent system if and only if the component states are exchangeable. We also discuss conditions for obtaining an alternative representation of the system reliability in which the signature is replaced by its non-i.i.d. extension. Finally, we discuss conditions for the system reliability to have both representations. [less ▲]

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See detailOn simplified handling of state events in time-domain simulation
Fabozzi, Davide ULg; Chieh, Angela S.; Panciatici, Patrick et al

in Proceedings of the 17th PSCC (2011, August)

The power system models typically used in dynamic simulations involve discrete events in addition to the standard differential-algebraic equations. Those events cause the system to jump from one ... [more ▼]

The power system models typically used in dynamic simulations involve discrete events in addition to the standard differential-algebraic equations. Those events cause the system to jump from one continuous behavior to another. Solvers have to handle those jumps. This paper focuses on simplified time simulation where large steps are used in conjunction with stiff-decay integration methods to obtain approximate solutions in short computing times. In the proposed simulation scheme, the simulation time steps are not synchronized with the system jumps, which are treated a posteriori in a corrective step. In this context, the paper analyzes several simple nonlinear models involving limiters, switches, minimum gates, etc. from which some precautions to be taken at the modelling and solving stages are stressed. The paper also reports on results obtained with a representative power system model. [less ▲]

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See detailOn Skinner's disenchantment
Richelle, Marc ULg

in Counselling Psychology Quarterly (1988), 1(2-3), 317-320

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See detailOn some drawbacks and possible improvements of a lagrangian finite element approach for simulating incompressible flows
Cerquaglia, Marco Lucio ULg; Deliège, Geoffrey ULg; Boman, Romain ULg et al

Conference (2015)

In this paper a Lagrangian finite element approach for the simulation of incompressible flows is presented, based on the so-called Particle Finite Element Method (PFEM). The spatial discretization and the ... [more ▼]

In this paper a Lagrangian finite element approach for the simulation of incompressible flows is presented, based on the so-called Particle Finite Element Method (PFEM). The spatial discretization and the definition of the boundary terms are discussed in detail with a specific focus on free-surface flows. Additionally, some problems that can arise from the use of such a method are pointed out. Some numerical examples are given and discussed in the last section of the paper. [less ▲]

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See detailOn some stability properties of the discretization of damped propagation of shallow-water inertia–gravity waves on the Arakawa B-grid
Beckers, Jean-Marie ULg

in Ocean Modelling (1999), 1(2-4), 53-69

We investigate a problem mentioned by Deleersnijder and Campin (Deleersnijder, E., & Campin, J. -M. (1993). Ocean Modelling 97, 2), who looked at the problem of the discretization of inertia–gravity waves ... [more ▼]

We investigate a problem mentioned by Deleersnijder and Campin (Deleersnijder, E., & Campin, J. -M. (1993). Ocean Modelling 97, 2), who looked at the problem of the discretization of inertia–gravity waves in the staggered B-grid. We generalize this study by adding diffusion. General stability conditions are found with the help of Miller's theorem, and the paradox found in Deleersnijder and Campin (Deleersnijder, E., & Campin, J. -M. (1993). Ocean Modelling 97, 2) is discussed. It is argued that it stems from inappropriate application of boundary conditions in conjunction with a Coriolis force treatment which could produce mechanical work. [less ▲]

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See detailOn standardness and I-cosiness
Laurent, Stéphane ULg

in Séminaire de Probabilités (2010), XLIII

The object of study of this work is the invariant characteristics of filtrations in discrete, negative time, pioneered by Vershik. We prove the equivalence between I-cosiness and standardness without ... [more ▼]

The object of study of this work is the invariant characteristics of filtrations in discrete, negative time, pioneered by Vershik. We prove the equivalence between I-cosiness and standardness without using Vershik’s standardness criterion. The equivalence between I-cosiness and productness for homogeneous filtrations is further investigated by showing that the I-cosiness criterion is equivalent to Vershik’s first level criterion separately for each random variable. We also aim to derive the elementary properties of both these criteria, and to give a survey and some complements on the published and unpublished literature. [less ▲]

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See detailOn the (13) CN/(12) CN Isotopic Ratio in Comet Hale-Bopp
Schulz, R.; Arpigny, Claude ULg; Manfroid, Jean ULg et al

in Bulletin of the American Astronomical Society (1997, July 01)

The carbon isotope abundance ratio, (12) C/(13) C, in comets is a key number to their origin. Its accurate determination from ground-based spectroscopy is, however, a difficult task since the observable ... [more ▼]

The carbon isotope abundance ratio, (12) C/(13) C, in comets is a key number to their origin. Its accurate determination from ground-based spectroscopy is, however, a difficult task since the observable emissions of (13) C-containing molecules are very weak. Due to its exceptional brightness, comet Hale-Bopp provided a unique opportunity to look for (13) C and derive the (12) C/(13) C isotopic ratio. We observed the comet with the high-resolution spectrograph SOFIN mounted on the 2.56m Nordic Optical Telescope on La Palma, Canary Islands. High-resolution spectra of the R-branch of the CN (0-0) band were obtained between Apr. 7 and 13, 1997, when the comet was at r = 0.9 AU and Delta = 1.4 AU. Owing to the heliocentric velocity effect on the fluorescence excitation rates, this period was particularly favourable to search for the R(8) and R(7) emission lines of the (13) CN isotope. Because of the strong continuum in the coma of Hale-Bopp we took our measurements at a certain location in the coma away from the nucleus and from any dust jets. Our first preliminary reduction and analysis show, after careful continuum subtraction, a clear detection of a line at the position predicted for R(8) and and an indication of a line at the predicted position of R(7). The R(8) line can be used to determine the (12) C/(13) C isotopic ratio and the first preliminary values will be given. [less ▲]

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See detailOn the accuracy of adults’ auditory perception of normophonic and dysphonic children’s personality.
Verduyckt, Ingrid; Remacle, Marc; Morsomme, Dominique ULg

in Logopedics, Phoniatrics, Vocology (in press)

We investigated the accuracy of auditory inferences of personality of Belgian children with vocal fold nodules (VFN). External judges (N=57) were asked to infer the personality of normophonic (NP ... [more ▼]

We investigated the accuracy of auditory inferences of personality of Belgian children with vocal fold nodules (VFN). External judges (N=57) were asked to infer the personality of normophonic (NP) children and children with VFN (N=10) on the basis of vowels and sentences. The auditory inferred profiles were compared to the actual personality of NP and VFN children. Positive and partly accurate inferences of VFN children’s personality were made on the basis of connected speech, while sustained vowels yielded negative and inaccurate inferences of personality traits of children with VFN. Dysphonic voice quality, as defined by the overall severity of vocal abnormality, conveyed inaccurate and low degrees of Extraversion. This effect was counterbalanced in connected speech by faster speaking rate that accurately conveyed higher degrees of Extraversion, a characteristic trait of VFN children’s actual personality. [less ▲]

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See detailOn the accuracy of analytical models of TCP throughput
El Khayat, Ibtissam; Geurts, Pierre ULg; Leduc, Guy ULg

in Lecture Notes in Computer Science (2006, May), 3976

Based on a large set of TCP sessions we first study the accuracy of two well-known analytical models (SQRT and PFTK) of the TCP average rate. This study shows that these models are far from being accurate ... [more ▼]

Based on a large set of TCP sessions we first study the accuracy of two well-known analytical models (SQRT and PFTK) of the TCP average rate. This study shows that these models are far from being accurate on average. Actually, our simulations show that 70% of their predictions exceed the boundaries of TCP-Friendliness, thus questioning their use in the design of new TCP-Friendly transport protocols. Our study also shows that the inaccuracy of the PFTK model is largely due to its inability to make the distinction between the two packet loss detection methods used by TCP: triple duplicate acknowledgments or timeout expirations. We then use supervised learning techniques to infer models of the TCP rate. These models show important accuracy improvements when they take into account the two types of losses. This suggests that analytical model of TCP throughput should certainly benefit from the incorporation of the timeout loss rate. [less ▲]

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See detailOn the accuracy of the reduction of UVBY photometry
Manfroid, Jean ULg; Heck, A.

in Astronomy and Astrophysics (1984), 132

By simulating uvby observations under various conditions, an analysis has been made of the precision reachable by a photometric reduction algorithm proposed in an earlier paper (Manfroid and Heck, 1983 ... [more ▼]

By simulating uvby observations under various conditions, an analysis has been made of the precision reachable by a photometric reduction algorithm proposed in an earlier paper (Manfroid and Heck, 1983). The influence of variations in parameters, such as the number of nights or the number of standard stars, is discussed. It is shown how the grouping of nights in the reduction procedure allows the observer to spend less time on standard stars measurements, while improving the accuracy of the results. The difficulty of giving a realistic value for the precision of the reductions in actual conditions is stressed. The inclusion of secondary standards is also recommended. [less ▲]

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See detailOn the accurate selection of asymptotic detection thresholds for Infit and Outfit indexes of person fit
Magis, David ULg; Raîche, Gilles; Béland, Sébastien

Conference (2012, April 11)

It exists a bunch of person fit indexes but Lz (Drasgow, Levine, & Williams, 1985), Infit mean square W (Wright & Masters, 1982) and Outfit mean square U (Wright & Stone, 1979) are certainly the most ... [more ▼]

It exists a bunch of person fit indexes but Lz (Drasgow, Levine, & Williams, 1985), Infit mean square W (Wright & Masters, 1982) and Outfit mean square U (Wright & Stone, 1979) are certainly the most popular. However, they have the undesirable property that their limiting distribution depends on the true ability level, which is generally unknown. In addition, the asymptotic distribution of U and W indexes was not clearly stated. Snijders (2001) proposed a generalization of the index Lz to incorporate estimated ability levels in its computation, and derived subsequent asymptotic normality of this modified Lz* index. The purpose of this talk is threefold. First, the generalization of Lz to Lz* is briefly sketched. Second, it is shown how this generalization can be successfully applied to both U and W indexes, yielding generalized U* and W* indexes respectively. Third, the accuracy of generalized indexes in detecting person (mis)fit is assessed through a simulation study. Three situations were investigated: (a) absence of misfit; (b) presence of cheating (yielding spuriously high scores); (c) presence of inattention (yielding spuriously low scores). Several conditions were varied, such as test length and aberrance rates when misfit was introduced. Response patterns were generated under the Rasch model and maximum likelihood estimation was performed to obtain the ability estimates. Several significance levels were selected. It is observed, that the generalized indexes Lz*, U* and W* better recover the significance level than their standard alternatives Lz, U and W respectively, while they are more powerful in identifying the two types of person misfit. In particular, the modified index W* has the best improvement in performance with respect to its original version W. It is concluded that Snijders' generalization of Lz index to Lz* is also accurate for U and W indexes under Rasch modelling. Possible extensions to other person fit indexes, such as ECI indexes (Tatsuoka, 1984), other ability estimators, and other IRT models are eventually briefly discussed. [less ▲]

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See detailOn the Active Centers of Serine and Zn II DD-carboxyppetidases
Charlier, Paulette ULg; Coyette, Jacques ULg; Dideberg, Otto et al

in Gregory, G.I. (Ed.) Recent advances in the Chemistry of beta-lactam antibiotics (1980)

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See detailOn the advantage of using risk curves to assess flood protection measures
Dewals, Benjamin ULg; Detrembleur, Sylvain ULg; Archambeau, Pierre ULg et al

in Mambretti, Stefano (Ed.) Environmental Risk (2012)

Modern flood management approaches require the quantification of flood risk, accounting for the hazard component (flood frequency and inundation intensity) as well as the vulnerability of the floodplains ... [more ▼]

Modern flood management approaches require the quantification of flood risk, accounting for the hazard component (flood frequency and inundation intensity) as well as the vulnerability of the floodplains (exposure, value and susceptibility). In this chapter, we present a detailed flood risk model, in which flow computation, monetary valuation of the assets and damage calculation are conducted at the scale of individual buildings or facilities. To avoid the shortcoming of focusing on economic damage, psycho-social impacts of floods are also included in the analysis. The model has been applied to evaluate three flood protection measures on a river reach in the Meuse basin (Belgium). The resulting risk curves show that such a micro-scale risk analysis provides important insights into the relative influence of the different flood protection measures. This could neither be evaluated through a more standard hydraulic analysis nor through the quantification of flood risk by only a single number. [less ▲]

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See detailOn the advantages of economically designed the Hotelling’s T2 control chart with variable sample sizes and sampling intervals
Faraz, Alireza ULg; kazemzadeh, R. B.; Parsian, Ahmad et al

in Quality & Quantity (2012), 46(1), 39-53

Faraz and Parsian (Statistical Paper, 47: 569–593, 2006) have shown that the double warning lines (DWL) scheme detects process shifts more quickly than the other variable ratio sampling schemes such as ... [more ▼]

Faraz and Parsian (Statistical Paper, 47: 569–593, 2006) have shown that the double warning lines (DWL) scheme detects process shifts more quickly than the other variable ratio sampling schemes such as variable sample sizes (VSS), variable sampling intervals (VSI) and variable sample sizes and sampling intervals (VSSVSI). In this paper, the DWLT2control chart for monitoring the process mean vector is economically designed. The cost model proposed by Costa and Rahim (Journal of Applied Statistics, 28: 875–885, 2001) is used here and is minimized through a genetic algorithm (GA) approach. Then the effects of the model parameters on the chart parameters and resulting operating loss is studied and finally a comparison between all possible variable ratio sampling (VRS) schemes are made to choose the best option economically. [less ▲]

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See detailOn the Advantages of Using a Strong Coupling Variational Formulation to Model Electro-Mechanical Problem
Rochus, Véronique ULg; Rixen, D. J.; Golinval, Jean-Claude ULg

in Thermal, Mechanical and Multiphysics Simulation and Experiments in Micro/Nanoelectronics and Systems, Proceedings of EuroSimE 2006 (2006, April)

This paper presents the advantages of a strong coupled formulation to model the electro-mechanical coupling appearing in MEMS. Usually the classical softwares use a staggered methodology iterating between ... [more ▼]

This paper presents the advantages of a strong coupled formulation to model the electro-mechanical coupling appearing in MEMS. Usually the classical softwares use a staggered methodology iterating between two different codes to obtain the solution of the coupled problem. In this research a strong coupled formulation is proposed and a tangent stiffness matrix of the whole problem is computed. Using this matrix, nonlinear algorithms such as the Riks-Crisfield algorithm may be applied to solve the static nonlinear problem and determine accurately the static pull-in voltage. Moreover, the natural frequencies may be computed around each equilibrium positions. The dynamic behaviour of the structure may also be studied and two new parameters are defined: the dynamic pull-in voltage and the dynamic pull-in time. This strong coupled methodology deriving from variational principle may also be used for topology optimisation and extended finite elements. [less ▲]

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