ORBi Open Repository and Bibliography
In may 2007, the ULg's Administrative Board (joined in June 2007 by the FUSAGx) decided to create an institutional repository and defined a strong institutional self-archiving policy to increase the visibility, accessibility and impact of the University's publications (Board's decision).
This decision led to the official launch, in November 2008, of the ORBi platform including both the Academic Bibliography and the Institutional Repository of the Wallonia-Europe University Academy.
Numerical study of intrinsic features of isolas in a 2-dof nonlinear system - Detroux, Thibaut; Noël, Jean-Philippe; Masset, Luc; Kerschen, Gaëtan; Virgin, Lawrence N.
In the present paper, isolated response curves in a nonlinear system consisting of two masses
sliding on a horizontal guide are examined. Transverse springs are attached to one mass to provide the nonlinear restoring force, and a harmonic motion of the complete system is imposed by prescribing the displacement of their supports. Numerical simulations are carried out to study the conditions of existence of isolated solutions, their bifurcations, their merging with the main response branch and their basins of attraction. This is achieved using tools including nonlinear normal modes, energy balance, harmonic balance-based continuation and bifurcation tracking, and global analysis.
Geophysical investigation of the Hockai Fault Zone, Eastern Belgium - Havenith, Hans-Balder; Nguyen, Frédéric; Halleux, Lucien; Hölz, Sebastian; Camelbeeck, Thierry
In the frame of a regional project evaluating the geothermal potential of the Wallonian Region of Belgium, the Hockai Fault Zone has been identified as one of the most interesting targets. It is a seismically active fault zone that hosted the largest historical earthquake in Northwestern Europe, the M6-6.5 Verviers event in 1692 as well as a swarm of small earthquakes that was recorded in 1989-90. On the surface, the presence of the fault zones is marked by a series of geomorphic features, such as several landslides near the borders in the northern part, repeated NW-SE oriented scarps all along...
Recent Advances in Batch Mode Reinforcement Learning: Synthesizing Artificial Trajectories - Fonteneau, Raphaël
Batch mode reinforcement learning (BMRL) is a field of research which focuses on the inference of high-performance control policies when the only information on the control problem is gathered in a set of trajectories. When the (state, action) spaces are large or continuous, most of the techniques proposed in the literature for solving BMRL problems combine value or policy iteration schemes from the Dynamic Programming (DP) theory with function approximators representing (state-action) value functions. While successful in many studies, the use of function approximators for solving BMRL problems has also drawbacks. In particular, the use of function approximator makes performance...
From Bad Models to Good Policies: an Intertwined Story about Energy and Reinforcement Learning - Fonteneau, Raphaël
Batch mode reinforcement learning is a subclass of reinforcement learning for which the decision making problem has to be addressed without model, using trajectories only (no model, nor simulator nor additional interactions with the actual system). In this setting, we propose a discussion about a minmax approach to generalization for deterministic problems with continuous state space. This approach aims at computing robust policies considering the fact that the sample of trajectories may be arbitrarily bad. This discussion will be intertwined with the description of a fascinating batch mode reinforcement learning-type problem with trajectories of societies as input, and for which...