University of Mons

About: University of Mons is a education organization based out in Mons, Belgium. It is known for research contribution in the topics: Large Hadron Collider & Standard Model. The organization has 3073 authors who have published 9465 publications receiving 294776 citations.

Condensed Representation of Database Repairs for Consistent Query Answering

Abstract: Repairing a database means bringing the database in accordance with a given set of integrity constraints by applying modifications that are as small as possible. In the seminal work of Arenas et al. on query answering in the presence of inconsistency, the possible modifications considered are deletions and insertions of tuples. Unlike earlier work, we also allow tuple updates as a repair primitive. Update-based repairing is advantageous, because it allows rectifying an error within a tuple without deleting the tuple, thereby preserving other consistent values in the tuple. At the center of the paper is the problem of query answering in the presence of inconsistency relative to this refined repair notion. Given a query, a trustable answer is obtained by intersecting the query answers on all repaired versions of the database. The problem arising is that, in general, a database can be repaired in infinitely many ways. A positive result is that for conjunctive queries and full dependencies, there exists a condensed representation of all repairs that permits computing trustable query answers.

Computational Design of Thermally Activated Delayed Fluorescence Materials: The Challenges Ahead

Abstract: Thermally activated delayed fluorescence (TADF) offers promise for all-organic light-emitting diodes with quantum efficiencies competing with those of transition-metal-based phosphorescent devices. While computational efforts have so far largely focused on gas-phase calculations of singlet and triplet excitation energies, the design of TADF materials requires multiple methodological developments targeting among others a quantitative description of electronic excitation energetics, fully accounting for environmental electrostatics and molecular conformational effects, the accurate assessment of the quantum mechanical interactions that trigger the elementary electronic processes involved in TADF, and a robust picture for the dynamics of these fundamental processes. In this Perspective, we describe some recent progress along those lines and highlight the main challenges ahead for modeling, which we hope will be useful to the whole TADF community.

(Plasticized) polylactide/(organo-)clay nanocomposites by in situ intercalative polymerization

Abstract: Both intercalated and exfoliated poly(L,L-lactide) (P(L,L-LA)/organomodified montmorillonite nanocomposites were synthesized by in situ ring-opening polymerization of L,L-lactide, in bulk, directly in the presence of the nano-filler. Intercalation of polyester chains was found to appear even for natural unmodified montmorillonite-Na + , while exfoliation occurred when the aluminosilicate layers were modified by ammonium cations bearing primary hydroxyl groups. Clay delamination was effectively triggered by the grafting reaction of the growing PLA chains onto the hydroxyl groups. Aluminium triisopropoxide, triethylaluminium, and stannous octoate, as initiating or co-initiating species, were compared in terms of polymerization control. The influence of nanoclay content (from 1 to 10 wt.-% in inorganics) on morphology and thermal behavior was also studied. In parallel, a highly filled nanocomposite (called master-batch), prepared by in situ polymerization, was dispersed into a (plasticized) preformed polylactide matrix in the molten state, to reach a better clay delamination than that obtained by direct melt blending. Finally, L,L-lactide and α,ω-dihydroxylated poly(ethylene glycol) (PEG 1000) were copolymerized in presence of clay in order to study the behavior of the resulting triblocks towards nanocomposite formation.

From Spinal Central Pattern Generators to Cortical Network: Integrated BCI for Walking Rehabilitation

Abstract: Success in locomotor rehabilitation programs can be improved with the use of brain-computer interfaces (BCIs). Although a wealth of research has demonstrated that locomotion is largely controlled by spinal mechanisms, the brain is of utmost importance in monitoring locomotor patterns and therefore contains information regarding central pattern generation functioning. In addition, there is also a tight coordination between the upper and lower limbs, which can also be useful in controlling locomotion. The current paper critically investigates different approaches that are applicable to this field: the use of electroencephalogram (EEG), upper limb electromyogram (EMG), or a hybrid of the two neurophysiological signals to control assistive exoskeletons used in locomotion based on programmable central pattern generators (PCPGs) or dynamic recurrent neural networks (DRNNs). Plantar surface tactile stimulation devices combined with virtual reality may provide the sensation of walking while in a supine position for use of training brain signals generated during locomotion. These methods may exploit mechanisms of brain plasticity and assist in the neurorehabilitation of gait in a variety of clinical conditions, including stroke, spinal trauma, multiple sclerosis, and cerebral palsy.