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See detailComptes-rendus du symposium « Les acarioses cutanées des animaux de compagnie en dermatologie vétérinaire »
Mignon, Bernard ULg

Book published by Presses de la Faculté de Médecine Vétérinaire de l’Université de Liège (2002)

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See detailComptes-rendus du symposium « Les dermatophytoses des carnivores domestiques en dermatologie vétérinaire »
Mignon, Bernard ULg

Book published by Presses de la Faculté de Médecine Vétérinaire de l’Université de Liège (2000)

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See detailComptines de dentellières brugeoises (1730-1850): entre travail, école et jeu, colère et prière
Peere, Isabelle ULg

in Barna, Gabor, Kriza, Ildiko (Ed.) Folk Ballads, Ethics, Moral Issues (2002)

An investigation of the song corpus of Lootens and Feys's Chants populaires flamands, a published collection of Flemish popular songs transcribed from the lips of a middle-class lady born in Bruges in ... [more ▼]

An investigation of the song corpus of Lootens and Feys's Chants populaires flamands, a published collection of Flemish popular songs transcribed from the lips of a middle-class lady born in Bruges in 1795. [less ▲]

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See detailLes comptines et leur utilité dans le développement de l’enfant
Gauthier, Jean-Marie ULg; Lejeune, C.

in Neuropsychiatrie de l'Enfance et de l'Adolescence (2008), 56

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See detailCompulsory inspection of crop sprayers already in use in Belgium: Selection of control method
Huyghebaert, Bruno; Mostade, Olivier; Carré, J. et al

in AgEng Madrid 96 (1996)

A European stream leads member countries to take action on sprayer conformity. Volontary inspection of crop sprayers are carried out in several countries. These control methods are not always specifically ... [more ▼]

A European stream leads member countries to take action on sprayer conformity. Volontary inspection of crop sprayers are carried out in several countries. These control methods are not always specifically defined. Other countries, such as Germany, Holland and Belgium, have established a compulsory inspection of crop sprayers already in use. In these cases, inspection methods and practical organisation have been clearly and officially defined. The Belgian Federal Ministry of Agriculture implemented on 04 September 1995 a compulsory inspection of crop sprayers in use in Belgium. Prior to that, the first goal was to choose a method adapted to an “on site” inspection. The control procedure that has been selected for the whole of Belgium is different from that practiced in many countries where the patternator is used. The practical organisation on site is also quite different. [less ▲]

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See detailComputation and approximation of the inverse of relationship matrices between genotyped animals: Algorithms and Applications
Faux, Pierre ULg

Doctoral thesis (2014)

The recent developments in molecular biology have made available thousands of genetic markers, allowing livestock genotyping at a reasonable cost and the subsequent development of genomic prediction. The ... [more ▼]

The recent developments in molecular biology have made available thousands of genetic markers, allowing livestock genotyping at a reasonable cost and the subsequent development of genomic prediction. The single-step procedure, a unified approach of genomic prediction, requires inversion of two matrices gathering additive relationships between genotyped animals: the genomic relationship matrix (G) and a part of the additive relationship matrix (A22). The inverse of A22 may also be interesting for other applications. Matrix inverse can be constructed successively by, first, computing, for each animal, the vector containing contributions of other animals to its relationship and, secondly, adding the product of each vector of contributions by itself to a zeroed matrix. The objectives of this thesis were (1) to propose algorithms to compute or to approximate the vector of contributions and (2) to test the numerical efficiency of these algorithms (computing speed, memory use and, if needed, approximation accuracy). Computing contributions covered two points: (1) finding or approximating which contributions are different from zero, and (2) computing the value of contributions considered as non-zero. In the first approach, we considered that animals closely related have non-zero contributions and approximated their values by linear regression. This approach was extended in a recursive way. In the second approach, we empirically determined the set of non-zero contributions by a heuristic algorithm of pedigree exploration (only for the case of A22). Values were then computed either by linear regression, or using the already computed inverse. We also tested an approximation strategy: limiting the number of extracted generations of non-genotyped ancestors to reduce pedigree complexity. In a third approach, we followed the same heuristic algorithm as before but restricted the pedigree exploration to find out which animals have a non-zero contribution. Their values were approximated by linear regression. The presentation of the different approaches is followed by a general discussion in which the approaches are compared. It was found that the best compromise between speed, memory and approximation accuracy was achieved by the last approach for the case of A22. Use of this last approach simplified computations and therefore made predictions more feasible. However, for the case of G, no sufficient approximations could be reach in a reasonable time. Perspectives of other uses of algorithms developed and of future researches were drawn, as well as practical perspectives for animal breeding. [less ▲]

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See detailComputation and evaluation of wall shear stress distribution at the lower surface of a radial flow cell.
Detry, Jean; Jensen, B.; Deroanne, Claude et al

in ECI International Conferences : Heat Exchanger Fouling and Cleaning VII (2007, July)

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See detailComputation of bounded feed-forward control for underactuated multibody systems using nonlinear optimization
Seifried, Robert; Guimaraes Bastos Junior, Guaraci ULg; Bruls, Olivier ULg

in Proceedings in Applied Mathematics and Mechanics, Volume 1, Special Issue: 82nd Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM) (2011)

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See detailComputation of damped nonlinear normal modes with internal resonances: a boundary value approach
Renson, Ludovic ULg; Touzé, Cyril; Kerschen, Gaëtan ULg

in Proceedings of the 8th European Nonlinear Dynamics Conference (ENOC 2014) (2014, July)

This paper considers the computation of nonlinear normal modes (NNMs) defined as two-dimensional manifolds in phase space. Because existing methods use explicit manifold parameterization, NNM computation ... [more ▼]

This paper considers the computation of nonlinear normal modes (NNMs) defined as two-dimensional manifolds in phase space. Because existing methods use explicit manifold parameterization, NNM computation in the presence of internal resonances requires multiple pairs of constraint coordinates. This paper investigates an alternative method for which the manifold is computed using successive boundary value problems. [less ▲]

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See detailComputation of Directional Impulse Responses in Rooms for Better Auralization
Embrechts, Jean-Jacques ULg; Werner, Nicolas; Lesoinne, Stéphane ULg

in Proceedings of the 118th Convention of the Audio Engineering Society (2005)

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See detailThe Computation of Equating Errors in International Surveys in Education
Monseur, Christian ULg; Berezner, Alla

in Journal of Applied Measurement (2007), 8(3), 323-35

Since the IEA's Third International Mathematics and Science Study, one of the major objectives of international surveys in education has been to report trends in achievement. The names of the two current ... [more ▼]

Since the IEA's Third International Mathematics and Science Study, one of the major objectives of international surveys in education has been to report trends in achievement. The names of the two current IEA surveys reflect this growing interest: Trends in International Mathematics and Science Study (TIMSS) and Progress in International Reading Literacy Study (PIRLS). Similarly a central concern of the OECD's PISA is with trends in outcomes over time. To facilitate trend analyses these studies link their tests using common item equating in conjunction with item response modelling methods. IEA and PISA policies differ in terms of reporting the error associated with trends. In IEA surveys, the standard errors of the trend estimates do not include the uncertainty associated with the linking step while PISA does include a linking error component in the standard errors of trend estimates. In other words, PISA implicitly acknowledges that trend estimates partly depend on the selected common items, while the IEA's surveys do not recognise this source of error. Failing to recognise the linking error leads to an underestimation of the standard errors and thus increases the Type I error rate, thereby resulting in reporting of significant changes in achievement when in fact these are not significant. The growing interest of policy makers in trend indicators and the impact of the evaluation of educational reforms appear to be incompatible with such underestimation. However, the procedure implemented by PISA raises a few issues about the underlying assumptions for the computation of the equating error. After a brief introduction, this paper will describe the procedure PISA implemented to compute the linking error. The underlying assumptions of this procedure will then be discussed. Finally an alternative method based on replication techniques will be presented, based on a simulation study and then applied to the PISA 2000 data. [less ▲]

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See detailComputation of induced fields into the human body by dual Finite Element formulations
Scorretti, R.; Vazquez Sabariego, Ruth ULg; Morel, L. et al

in IEEE Transactions on Magnetics (2012), 48(2), 783-786

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See detailComputation of induced fields into the human body by using dual formulations
Scorretti, Riccardo; V Sabariego, Ruth ULg; Morel, L. et al

(2011)

In this work we present the use of two dual formulations to compute Extremely Low frequency (ELF) induced fields into the human body. This allows to estimate the numerical error, as well as rigorously ... [more ▼]

In this work we present the use of two dual formulations to compute Extremely Low frequency (ELF) induced fields into the human body. This allows to estimate the numerical error, as well as rigorously bound the (global) co-energy. This method is here applied to the classical case of the exposure to a homogeneous magnetic field. [less ▲]

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See detailComputation of nonlinear normal modes of large structures: application to a full-scale aircraft
Peeters, Maxime ULg; Renson, Ludovic ULg; Kerschen, Gaëtan ULg et al

in Proceedings of the 7th European Nonlinear Dynamics Conference (ENOC 2011) (2011)

The objective of this paper is to demonstrate that the numerical computation of the nonlinear normal modes (NNMs) of complex real-world structures is now within reach. The application considered in this ... [more ▼]

The objective of this paper is to demonstrate that the numerical computation of the nonlinear normal modes (NNMs) of complex real-world structures is now within reach. The application considered in this study is the airframe of the Morane-Saulnier Paris aircraft, whose ground vibration tests exhibited some nonlinear structural behaviors. The NNMs are computed using a numerical algorithm combining shooting and pseudo-arclength continuation. [less ▲]

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See detailComputation of nonlinear normal modes through continuation methods
Renson, Ludovic ULg; Kerschen, Gaëtan ULg

Conference (2013, May)

In mechanical engineering, performance enhancement usually results in lighter and more flexible structures and pushes the limits of the system operating envelope. Nonlinearity is therefore becoming a ... [more ▼]

In mechanical engineering, performance enhancement usually results in lighter and more flexible structures and pushes the limits of the system operating envelope. Nonlinearity is therefore becoming a frequent occurrence and linear design tools show their limitations. To overcome these issues, nonlinear normal modes (NNMs) were introduced in structural dynamics as a direct extension of linear normal modes to nonlinear systems. Our contribution reviews the history and the new trends for the computation of NNMs in mechanical engineering. Specifically, algorithms for the continuation of periodic solutions were first developed. Such algorithms are now well-established and applicable to large-scale systems such as real-life aerospace structures. To further extend the concept of NNMs to nonconservative systems, the definition of an NNM as an invariant manifold in the system’s phase space was introduced. Again, continuation techniques are particularly well suited for computing these invariant manifolds. The geodesic level set method developed by Krauskopf and Osinga [1] as well as the “PDE formulation” method of Guckenheimer and Vladimirsky [2] are both considered. [1] Krauskopf, B. and H. Osinga (2003). "Computing Geodesic Level Sets on Global (Un)stable Manifolds of Vector Fields." SIAM Journal on Applied Dynamical Systems 2(4): 546-569. [2] Guckenheimer, J. and A. Vladimirsky (2004). "A Fast Method for Approximating Invariant Manifolds." SIAM Journal on Applied Dynamical Systems 3(3): 232-260. [less ▲]

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See detailComputation of Nonlinear Normal Modes using Numerical Continuation Techniques
Peeters, Maxime ULg; Viguié, Régis ULg; Serandour, Guillaume et al

in International Confernce on Advanced Computational Methods in Engineering, Liège, 2008 (2008)

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See detailCOMPUTATION OF NONLINEAR NORMAL MODES, PART I: NUMERICAL CONTINUATION IN MATLAB
Peeters, Maxime ULg; Viguié, Régis ULg; Serandour, Guillaume et al

in Sixth EUROMECH Nonlinear Dynamics Conference, Saint Petersbourg, 2008 (2008)

The concept of nonlinear normal modes (NNMs) is discussed in the present paper and its companion, Part II. Because there is virtually no application of the NNMs to large-scale engineering structures ... [more ▼]

The concept of nonlinear normal modes (NNMs) is discussed in the present paper and its companion, Part II. Because there is virtually no application of the NNMs to large-scale engineering structures, these papers are an attempt to highlight one aspect that might drive their development in the future. Specifically, we support that numerical methods for the continuation of periodic solutions pave the way for an effective and practical computation of NNMs. In this context, we show that the NNM computation is possible with limited implementation effort. The proposed algorithm, implemented in MATLAB, relies on two main techniques, namely a shooting procedure and a method for the continuation of NNM motions. The algorithm is demonstrated using a 2DOF nonlinear system. A comparison with the results given by the AUTO software is achieved in Part II. [less ▲]

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See detailComputation of nonlinear normal modes, part II: numerical continuation in Auto
Serandour, Guillaume; Peeters, Maxime ULg; Kerschen, Gaëtan ULg et al

in Sixth EUROMECH Nonlinear Dynamics Conference, Saint Petersbourg, 2008 (2008)

The concept of nonlinear normal modes (NNMs) is discussed in the present paper and its companion, Part I. Because there is virtually no application of the NNMs to large-scale engineering structures, these ... [more ▼]

The concept of nonlinear normal modes (NNMs) is discussed in the present paper and its companion, Part I. Because there is virtually no application of the NNMs to large-scale engineering structures, these papers are an attempt to highlight one aspect that might drive their development in the future. Specifically, we support that numerical methods for the continuation of periodic solutions pave the way for an effective and practical computation of NNMs. In this context, we show that the NNMs computation is possible using an existing continuation software, namely AUTO07. This is demonstrated using a 2DOF nonlinear system. The results are compared with those obtained with the Matlab algorithm described in Part I. [less ▲]

Detailed reference viewed: 55 (10 ULg)