Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
See detailOn les désigne comme "handicapés mentaux" : Naissance et conséquence d'une étiquette
Beckers, Jacqueline ULg

in Sauvegarde de l'Enfance (1988), 1

Detailed reference viewed: 9 (0 ULg)
See detailOn mathematical concepts for the material world
Leclercq, Bruno ULg

Conference (2008, September 25)

Detailed reference viewed: 71 (6 ULg)
Full Text
Peer Reviewed
See detailOn micromechanical damage modeling in geomechanics: influence of numerical integration scheme
Levasseur, Séverine ULg; Collin, Frédéric ULg; Charlier, Robert ULg et al

in International Journal of Computational & Applied Mathematics (2013), 246

Tunnel excavations in deep rocks provide stress perturbations which initiate diffuse and/or localized damage propagation in the material. This damage phenomenon can lead to significant irreversible ... [more ▼]

Tunnel excavations in deep rocks provide stress perturbations which initiate diffuse and/or localized damage propagation in the material. This damage phenomenon can lead to significant irreversible deformations and changes in rock properties. In this paper, we propose to model such behavior by considering a micromechanically-based damage approach. The resulting micromechanical model, which also accounts for initial stress, is described and assessed through the numerical analysis of a synthetic tunnel drilling in Opalinus Clay. A particular emphasis is put on the numerical integration of the model. In particular, an appropriate choice of the latter is required to ensure the numerical stability and a confident prediction of excavation damaged zone around tunnels. [less ▲]

Detailed reference viewed: 38 (10 ULg)
See detailOn modal interactions in strongly nonlinear systems
Peeters, Maxime ULg; Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg

in Euromech 503, Nonlinear Normal Modes, Dimension Reduction and Localization in Vibrating Systems, Frascati, 2009 (2009)

Detailed reference viewed: 10 (4 ULg)
Full Text
Peer Reviewed
See detailOn multi-area control in electric power systems
Zima, Marek; Ernst, Damien ULg

in Proceedings of the 15th Power System Computation Conference (PSCC 2005) (2005)

In this paper we study the concept of electric power system control, when the responsibility for controlling the entire system is shared by agents controlling their assigned areas. Within this framework ... [more ▼]

In this paper we study the concept of electric power system control, when the responsibility for controlling the entire system is shared by agents controlling their assigned areas. Within this framework, we suggest to study the dynamics created by the interactions of agents. In particular, we discuss the relation that exists between the information available to the different agents and their optimisation objective, and the performance of the overall power system. Simulations results, carried out on a 39-node power system voltage control problem, are provided and analyzed. They highlight, among others, the sub-optimal performance level attained by the system when the different agents exchange information about their area dynamics without sharing a common control objective. [less ▲]

Detailed reference viewed: 43 (0 ULg)
Full Text
Peer Reviewed
See detailOn multi-area security assessment of large interconnected power systems
Wehenkel, Louis ULg; Glavic, Mevludin; Ernst, Damien ULg

in Proceedings of the Second Carnegie Mellon Conference in Electric Power Systems: Monitoring, Sensing, Software and its Valuation for the Changing electric Power Industry (2006)

The paper introduces a framework for information exchange and coordination of security assessment suitable for distributed multi-area control in large interconnections operated by a team of transmission ... [more ▼]

The paper introduces a framework for information exchange and coordination of security assessment suitable for distributed multi-area control in large interconnections operated by a team of transmission system operators. The basic idea of the proposed framework consists of exchanging just enough information so that each operator can evaluate the impact in his control area of contingencies both internal and external to his area. The framework has been thought out with the European perspective in mind where it is presently not possible to set up a transnational security coordinator that would have authority to handle security control over the whole or part of the European interconnection. Nevertheless, it can also be considered as an approach to handle security control in North-American Mega-RTOs, where it could help to circumvent problems of scalability of algorithms and maintainability of data by distributing them over the TSOs under the authority of the RTO. [less ▲]

Detailed reference viewed: 31 (0 ULg)
Full Text
Peer Reviewed
See detailOn natural and conformally invariant quantizations
Mathonet, Pierre ULg; Radoux, Fabian ULg

in Journal of the London Mathematical Society (2009), 80(1), 256-272

The concept of conformally equivariant quantization was introduced by Duval, Lecomte and Ovsienko for manifolds endowed with flat conformal structures. They obtained results of existence and uniqueness ... [more ▼]

The concept of conformally equivariant quantization was introduced by Duval, Lecomte and Ovsienko for manifolds endowed with flat conformal structures. They obtained results of existence and uniqueness (up to normalization) of such a quantization procedure. A natural generalization of this concept is to seek for a quantization procedure, over a manifold M, that depends on a pseudo-Riemannian metric, is natural, and is invariant with respect to a conformal change of the metric. The existence of such a procedure was conjectured by P. Lecomte and proved by C. Duval and V. Ovsienko for symbols of degree at most 2 and by S. Loubon Djounga for symbols of degree 3. In two recent papers, we investigated the question of existence of projectively equivariant quantizations using the framework of Cartan connections. Here we will show how the formalism developed in these works adapts in order to deal with the conformally equivariant quantization for symbols of degree at most 3. This will allow us to easily recover earlier results on the subject. We will then show how it can be modified in order to prove the existence of conformally equivariant quantizations for symbols of degree 4. [less ▲]

Detailed reference viewed: 14 (4 ULg)
See detailOn ne descend jamais deux fois dans le même flux sensoriel
Leclercq, Bruno ULg

Conference (2013, January 22)

Detailed reference viewed: 42 (4 ULg)
Full Text
Peer Reviewed
See detailOn osp(p+1,q+1|2r)-equivariant quantizations
Leuther, Thomas ULg; Mathonet, Pierre ULg; Radoux, Fabian ULg

in Journal of Geometry & Physics (2012), 62

Detailed reference viewed: 32 (12 ULg)
Full Text
Peer Reviewed
See detailOn Output feedback Nonlinear Model Predictive Control using high gain observers for a class of systems
Imsland, L.; Findeisen, R.; Bullinger, Eric ULg et al

in Proc. 6th IFAC Symposium on Dynamics and Control of Process Systems, DYCOPS-6 (2001)

Detailed reference viewed: 5 (0 ULg)
Full Text
Peer Reviewed
See detailOn period determination methods
Heck, A.; Manfroid, Jean ULg; Mersch, G.

in Astronomy and Astrophysics. Supplement Series (1985), 59

It is noted that the two large families of period determination techniques based on the Fourier transform and on the nonparametric algorithms derived from the theta-criterion by Lafler and Kinman (1965 ... [more ▼]

It is noted that the two large families of period determination techniques based on the Fourier transform and on the nonparametric algorithms derived from the theta-criterion by Lafler and Kinman (1965) are not equivalent to each other under general conditions. Instead, at best, all criteria may be expressed as the ratio of two quadratic forms. Numerical simulations have been conducted in order to compare the performance of Deeming's (1975) Fourier method, Burki et al.'s (1978) autocorrelation method, Lafler and Kinman's (1965) method, and the Renson (1978) and Stellingwerf (1978) methods. When applied to single-periodic phenomena, the tests indicate that none of the methods is clearly superior. [less ▲]

Detailed reference viewed: 11 (0 ULg)
Full Text
Peer Reviewed
See detailOn periodic reference tracking using batch-mode reinforcement learning with application to gene regulatory network control
Sootla, Aivar; Strelkowa, Natajala; Ernst, Damien ULg et al

in Proceedings of the 52nd Annual Conference on Decision and Control (CDC 2013) (2013, December)

In this paper, we consider the periodic reference tracking problem in the framework of batch-mode reinforcement learning, which studies methods for solving optimal control problems from the sole knowledge ... [more ▼]

In this paper, we consider the periodic reference tracking problem in the framework of batch-mode reinforcement learning, which studies methods for solving optimal control problems from the sole knowledge of a set of trajectories. In particular, we extend an existing batch-mode reinforcement learning algorithm, known as Fitted Q Iteration, to the periodic reference tracking problem. The presented periodic reference tracking algorithm explicitly exploits a priori knowledge of the future values of the reference trajectory and its periodicity. We discuss the properties of our approach and illustrate it on the problem of reference tracking for a synthetic biology gene regulatory network known as the generalised repressilator. This system can produce decaying but long-lived oscillations, which makes it an interesting application for the tracking problem. [less ▲]

Detailed reference viewed: 12 (0 ULg)
Full Text
Peer Reviewed
See detailOn periodical oscillations of Lurie systems with discontinuous nonlinearity
Efimov, Denis ULg

in Proc. 17th IFAC WC, Seoul, Korea (2008)

Sufficient conditions of global attracting limit cycle existence for Lurie system with sign nonlinearity are presented. It is assumed that the linear part of the system is output stabilizable, the ... [more ▼]

Sufficient conditions of global attracting limit cycle existence for Lurie system with sign nonlinearity are presented. It is assumed that the linear part of the system is output stabilizable, the nonlinearity has linear negative term plus positive one proportional to the output sign. Conditions of oscillatority in the sense of Yakubovich for this class of systems are also reestablished. [less ▲]

Detailed reference viewed: 25 (1 ULg)
Full Text
See detailOn peut se sentir wallon et belge
Jacquemain, Marc ULg

Article for general public (2008)

L'interview défend l'idée d'une identité wallonne "non nationale" qui se sent donc à l'aise au sein de la Belgique.

Detailed reference viewed: 28 (7 ULg)
Full Text
See detailOn photometric standards and color transformation
Manfroid, Jean ULg

in Calibration of Fundamental Stellar Quantities (1985)

The author has carried out a preliminary investigation of a method of observation and reduction which leads to a large improvement in the accuracy of the color transformation of photometric measurements ... [more ▼]

The author has carried out a preliminary investigation of a method of observation and reduction which leads to a large improvement in the accuracy of the color transformation of photometric measurements. This method involves the use of extra filters for some of the observations. It is argued that the better precision obtained is well worth the additional telescope work. [less ▲]

Detailed reference viewed: 7 (0 ULg)