Le revenu des personnes âgées. La fin de l'âge d'or?

Report (2001)

Actuellement les personnes âgées vivent un véritable âge d’or relativement à un passé récent. Leurs revenus moyens sont à peine plus bas que ceux d’autres classes d’âge. Dans ce groupe d’âge, les ... [more ▼]

Actuellement les personnes âgées vivent un véritable âge d’or relativement à un passé récent. Leurs revenus moyens sont à peine plus bas que ceux d’autres classes d’âge. Dans ce groupe d’âge, les inégalités de revenus sont faibles. C’est aux systèmes de retraite que l’on doit cela. Cet article indique que si l’on prend en compte les di¤érences de longévité, le système de retraite apparaît moins redistributif. Ensuite, il s’interroge sur l’avenir de cet âge d’or. Il apparaît nettement qu’il disparaîtra rapidement si rien ne change : des taux de dépendance accrus — conséquence de la longévité croissante et des faibles taux de participation des travailleurs âgés — conduisent nécessairement à une réduction radicale des protections. En revanche, si l’âge de la retraite peut être relevé, les conséquences du vieillissement pourront être neutralisées. [less ▲]

Behaviour of steel pallet rack structures under exceptional loading conditions - partial report

Report (2000)

In this report, the general context of steel storage rack systems subjected to fire is first introduced. The second section of the report is dedicated to the numerical finite element modelling of the ... [more ▼]

In this report, the general context of steel storage rack systems subjected to fire is first introduced. The second section of the report is dedicated to the numerical finite element modelling of the resistance and stability behaviour of a system in a particular building under static loading at ambient temperature. [less ▲]

User Manual for SAFIR A Computer Program for Analysis of Structures at Elevated Temperature Conditions

Report (1999)

The first published user's manual of SAFIR.

Pourquoi certains (beaucoup d')étudiants ne fréquentent-ils pas les dispositifs d'aide? Commission d'évaluation formative : document interne

Report (1999)

Qualité de vie et policiers liégeois, âgés de plus de 45 ans

Report (1999)

Evaluation des enseignements en 1re et 2e candidatures, année académique 1997-1998 : rapport de synthèse

Report (1998)

MAITRISE TECHNOLOGIQUE DE LA LIPOLYSE DANS LES CREMES RECONSTITUEES : Rapport n° 1 : période du 1er décembre 1997 au 31 mai 1998

Report (1998)

A basis for using fire modeling with 1-D thermal analyses of barriers/partitions to simulate 2-D and 3-D barrier/partition structural performance in real fires

Report (1998)

Layout Optimization : A Mathematical Programming Approach

Report (1997)

This paper presents applications of specially tailored methods of the mathematical programming approach for solving topology design problems formulated as an optimal material distribution, providing a way ... [more ▼]

This paper presents applications of specially tailored methods of the mathematical programming approach for solving topology design problems formulated as an optimal material distribution, providing a way to enlarge the scope of potential applications of topology optimization. The first feature of the methodology is to resort to dual maximization to solve optimization problems with a huge number of design variables, using the concept of Sequential Convex Programming (SCP). Here a central theme is the choice of convex approximations suited to the problems. First order approximations are firstly considered and compared. However, to increase the performances of the procedures (for example, to reduce the number of steps to arrive to a stationary design), a new approach to build un-expensive second approximation schemes, especially relevant for large scale problems, have been developed and validated. To illustrate the efficiency of the mathematical programming approach, the final part of the paper deals with an efficient treatment of perimeter constraints. Such constraints are essential to regularize material distribution with non optimal microstructures, but perimeter constraints are very difficult to handle in a numerical procedure for practical designs. The paper presents a solution to this problem that has been implemented and validated on a wide range of applications. [less ▲]

Les pommes de terre et les plants de pommes de terre en Région wallonne : rapport final

Report (1997)

Inventarisatiedossier ruilverkaveling Londerzeel

Report (1997)

Introduction à l'optimisation topologique

Report (1996)

Evolution des principaux types d'aides à la décision en matière de gestion forestière.

Report (1996)

Forest planning is more and more made of activities which require to take into account a great amount of various sets of ecological, economical and social data which have to be considered in a diversity ... [more ▼]

Forest planning is more and more made of activities which require to take into account a great amount of various sets of ecological, economical and social data which have to be considered in a diversity of space and time-scales. Facing such complexity the managers need of guidance in coming to the right decision. Some decision support systems are presented and briefly described as concerns nature, objectives and possible applications to concrete situations. [less ▲]

Efficiency measurement, multiple-output technologie and distance functions: With application to European Railways

Report (1996)

The single-output production function has long been regarded as one of the principle limitations of the econometric approach to technical efficiency measurement. If one wished to investigate efficiency in ... [more ▼]

The single-output production function has long been regarded as one of the principle limitations of the econometric approach to technical efficiency measurement. If one wished to investigate efficiency in a multiple-output industry using econometric methods one would usually either: (a) aggregate outputs into a single index of output (e.g., total revenue or a multilateral Tornqvist output index); or (b) attempt to model the technology using a dual cost function. The first of these methods require that output prices be observable (and reflect revenue maximising behaviour), while the latter approach requires an assumption of cost-minimising behaviour. There are a number of instances, however, when neither of these requirements are met (the public sector contains many examples). In this study we outline the recently developed distance function solution to the multi-output problem. The method is illustrated using data on European railways. Output-orientated, input-orientated and constant returns to scale distance functions are estimated using corrected ordinary least squares. The distance function estimates are also compared with production function estimates involving aggregate output measures. These comparisons indicate that, for the case of European railways, a production function involving a multilateral Tornqvist output index exhibits substantially less aggregation bias relative to a production function that uses total revenue as a measure of aggregate output. [less ▲]

Vol de voitures, assurance et fraude à l'assurance. L'exemple Français

Report (1995)

Problèmes elliptiques avec liaisons

Report (1994)

In this report, the theory of constrained elliptical problems is presented. Two classes of methods are used to solve such problems, which are the dualization and the penalty method. In the first one, use ... [more ▼]

In this report, the theory of constrained elliptical problems is presented. Two classes of methods are used to solve such problems, which are the dualization and the penalty method. In the first one, use is made of Lagrange multipliers. The justification of this method has been given by Brezzi in 1974. This theory is presented in the present report by a particularly simple way, where use is made of elementary hilbertian geometry. Our step, which consists in building the solution, emphasizes the natural character of Brezzi's conditions. Extending this analysis, it was rational to also examine the penalty method, which is often preferred because its simpler implementation. It is shown that the convergence of this method necessitate some hypotheses which are in most cases equivalent to Brezzi's conditions. [less ▲]

Optimalisation des opérations de tournage : la méthode de la puissance disponible

Report (1993)

Tailor's results on machining optimization always assume that the power of the machine tool is not a limitation. However, this not necessarily true, specially in the case of rough machining, where ... [more ▼]

Tailor's results on machining optimization always assume that the power of the machine tool is not a limitation. However, this not necessarily true, specially in the case of rough machining, where Taylorian optima are out of the power range of the machine. In this paper, an algorithm is proposed, where the machine capacity is the first consideration. The obtained result is then corrected in view of the tool life. [less ▲]

Considérations économiques relatives à l'usinage léger

Report (1993)

This report focuses on the classical Taylorian optimization of the cuting speed. An interesting result is the supply curve of the turning operation, which has an unconventional aspect when working outside ... [more ▼]

This report focuses on the classical Taylorian optimization of the cuting speed. An interesting result is the supply curve of the turning operation, which has an unconventional aspect when working outside of the productivity range [less ▲]

Morphologie à seuillage: application au lissage des formes

Report (1993)

La morphologie mathématique englobe différentes techniques de filtrage aussi variées qu'originales. Parmi l'imposante panoplie des filtres se distinguent ceux qui sont nés de la morphologie à seuillage ... [more ▼]

La morphologie mathématique englobe différentes techniques de filtrage aussi variées qu'originales. Parmi l'imposante panoplie des filtres se distinguent ceux qui sont nés de la morphologie à seuillage, encore appelée morphologie floue, très en vogue à l'heure actuelle. Ce document s'inscrit dans ce courant. Nous y définissons le concept central d'érosion partielle, simple transcription d'une opération déjà connue, pour l'étendre ensuite aux notions de dilatation, d'ouverture et de fermeture partielles. À l'inverse des développements récents en ce domaine, c'est l'aspect géométrique qui y tient le haut du pavé; les opérations partielles se conçoivent comme des interactions entre objets et non en termes de lois de probabilité. Elles conduisent à une série de procédés de lissage des contours d'images binaires gérés par un seuil unique et une famille d'éléménts structurants adaptés à l'application. Des techniques similaires sont évoquées pour des images en niveaux de gris. Nous introduisons ensuite le nouveau concept de polymorphisme d'un point. Ce dernier indique pour chaque point le nombre d'éléments structurants qui contiennent ce point. C'est par son entremise que pourront s'appliquer des procédés d'optimisation de filtrage puisqu'il fournit une mesure analytique. [less ▲]

Rapport d'activité 1990-1991

Report (1992)

Etude approchée des roulements rigides à billes chargé radialement, dans le cas des grandes vitesses

Report (1992)

The classical rolling bearing theory lies on the assumption that the rotational speed is low. The simplest correction for high speeds consists in adding only the centrifugal load. But even in this frame ... [more ▼]

The classical rolling bearing theory lies on the assumption that the rotational speed is low. The simplest correction for high speeds consists in adding only the centrifugal load. But even in this frame, the problem is by far complicated. However, in the case of a radial load, it is possible to develop an approximated formulation which easily leads to realistic results. This elementary theory may be used as a basis of comparison for more evolved theories, which may be useful. [less ▲]

Consistance de l'étude linéarisée des structures précontraintes

Report (1991)

The linearized study of pre-stressed structures is, by far, not a novelty. But its practical application led to a lot of disappointments, especially concerning rigid body modes, so that it seemed useful ... [more ▼]

The linearized study of pre-stressed structures is, by far, not a novelty. But its practical application led to a lot of disappointments, especially concerning rigid body modes, so that it seemed useful to try a restatement of this subject. After an exposition of the principles of this formulation, the attention is focused on the numerous simplifications which are commonly done, by tradition or for sake of simplicity. This study is illustrated by a lot of examples whose purpose is an aid for the physical understanding of the problem. [less ▲]

Centre d'étude de la modélisation des arbres : rapport d'activité 1990-1991

Report (1991)

Rapport d'activité du bureau de biométrie 1988-1989

Report (1990)

La presse écrite en province de Liège

Report (1990)

Etude de marché pour le quotidien "La Wallonie" sur l'évolution de la presse écrite en province de Liège et l'espace possible pour un quotidien marqué à gauhe mais "relooké".

Rapport d'activité du bureau de biométrie 1988

Report (1989)

Pseudorange

Report (1989)

Survol historique des utilisations pédagogiques de l'ordinateur au travers de faits saillants dans cinq pays : version provisoire

Report (1988)

Conception assistée par ordinateur d'un palier rigide à billes

Report (1988)

This report presents a program for the complete design of a deep groove ball bearing which is submitted to a plane sollicitation. This programs includes a catalogue consultation and the assessment of the ... [more ▼]

This report presents a program for the complete design of a deep groove ball bearing which is submitted to a plane sollicitation. This programs includes a catalogue consultation and the assessment of the tolerances of both races. For these, the computation is based on the exact nonlinear formulation of the problem, and not on approximate values of the catalogues. In particular, it allows to find the infuence of the clearance on the stiffness of the bearing. The bending moment is taken in account. In order to solve the nonlinear equations of the theory, a Newton-Raphson procedure is introduced. In this problem, a proper choice of the starting point is of paramount importance, as the reference position is stiffness-free. This problem is dicussed in detail. The second part of this report presents the ROULBI program and comments its different steps. [less ▲]

Définition de la masse d'eau ajoutée dans les phénomènes hydrodynamiques; (recherche obtenue dans le cadre des Actions Concertées et financées par le SPPS, impliquant la collaboration de trois services universitaires)

Report (1987)

Bureau de Biométrie - Rapport d'activité 1986

Report (1987)

Analyse cinématique des mécanismes - Logiciel CINEMA

Report (1986)

This report presents the fundamental concepts and an user manual of the CINEMA software, as developed in the Aerospace Laboratory of the University of Liège

Etude critique de quelques formulations de la théorie des coques en vue de l'application aux éléments finis

Report (1986)

Surface geometry and shell geometry, in the frame of general tensor calculus. Fundamentals of the theory of thin shells. Expressing strains from curvilinear components of the displacements. Applicability ... [more ▼]

Surface geometry and shell geometry, in the frame of general tensor calculus. Fundamentals of the theory of thin shells. Expressing strains from curvilinear components of the displacements. Applicability of the preceeding theory to finite elements. Expressing strains from the cartesian components of the displacements. Moderate rotation theory (curvilinear components). Moderate rotation theory (cartesian components). Quasi-plane and almost-plane shells. Shells with shearing strains (cartesian components). Shells with shear strains (curvilinear components). Moderate rotations of a shell with shear strains (curvilinear components). Re-interpretation and generaisation of Marguerre shallow shells. Conical shells. Quasi-conical shells. Axisymmetrical shells in cylindrical components. Annex : an introduction of the elasticity theory in curvilinear coordinates.Bibliography [less ▲]

Sondage sur les avis et souhaits d'enseignants du degré supérieur de l'enseignement primaire à propos des utilisations pédagogiques de l'ordinateur

Report (1985)

Théorie non linéaire des coques d'épaisseur modérée

Report (1984)

This report presents a theory of moderate thickness shells. From an error evaluation process which is founded on the compatibility equations, a strain energy exprssion is found, where stretching and ... [more ▼]

This report presents a theory of moderate thickness shells. From an error evaluation process which is founded on the compatibility equations, a strain energy exprssion is found, where stretching and bending are uncoupled. [less ▲]

Vibration d'une plaque console vrillée: influence de l'angle de vrillage sur les fréquences propres et les modes propres; comparaison de la méthode de calculs par éléments finis SAMCEF avec l'expérience et d'autres codes de calculs

Report (1983)

Réussir ou échouer à l'Université?

Report (1983)

Théorie des poutres faiblement vrillées

Report (1978)

A weakly pre-twisted beam theory is presented by an original way which renders the mathematical developments fairly simple. The proposed approach has the interesting property that in the finite element ... [more ▼]

A weakly pre-twisted beam theory is presented by an original way which renders the mathematical developments fairly simple. The proposed approach has the interesting property that in the finite element frame, the error of the theory converges to zero when the mesh is refined. [less ▲]

Etude de quelques réactions spécifiques de la fraction argileuse en présence de chaux

Report (1978)

L'intégration dans les éléments finis

Report (1976)

This paper presents some quadrature methods which may be successfully applied to finite elements.

On the approximation of incompressible solids in the displacement method

Report (1976)

A mathematical analysis of the numerical approximation to incompressibility with nearly incompressible displacement finite elements is presented. It explains why, as observed by many authors, convergence ... [more ▼]

A mathematical analysis of the numerical approximation to incompressibility with nearly incompressible displacement finite elements is presented. It explains why, as observed by many authors, convergence to the incompressible solution is not necessarily obtained when Poisson's ration is increased up to 0.5. It also allows predicting under which conditions convergence of the nearly incompressible approach is guaranteed. [less ▲]

Ferme Delsamme : action entre utopie et réalité

Report (n.d.)

Modélisation numérique de l'expérience SDZ pour l'Andra

Report (n.d.)

An in situ ventilation test (SDZ) is performed by the French national radioactive waste management agency (ANDRA) in the Meuse/Haute-Marne underground research laboratory. The aim is to characterise the ... [more ▼]

An in situ ventilation test (SDZ) is performed by the French national radioactive waste management agency (ANDRA) in the Meuse/Haute-Marne underground research laboratory. The aim is to characterise the effect of the desaturation and possible resaturation of the damaged zone located around an experimental gallery due to controlled ventilation imposed in this gallery. Hydro and hydro-mechanical numerical modellings are realised in order to acquire a better understanding of clayey rock behaviour and transfers occurring during the test. [less ▲]