Alban Derrien

• PhD Student at IMT Atlantique

This paper investigates cumulative scheduling in uncertain environments, using constraint programming. We present a new declarative characterization of robustness, which preserves solution quality. We highlight the significance of our framework on a crane assignment problem with business constraints.

Energetic Reasoning (ER) is a powerful filtering algorithm for the Cumulative constraint. Unfortunately, ER is generally too costly to be used in practice. One reason of its bad behavior is that many intervals are considered as relevant, although most of them should be ignored. In the literature, heuristic approaches have been developed in order to...

The construction of a Quasi-Cyclic Low Density Parity-Check (QC-LDPC) matrix is usually carried out in two steps. In the first step, a prototype matrix is defined according to certain criteria (size, girth, check and variable node degrees, etc.). The second step involves expansion of the prototype matrix. During this last phase, an integer value is...

Construction of good Non-Binary Low Density Parity Check codes

For all 8192 combinations of Allen’s 13 relations between one task with origin \(o_i\) and fixed length \(\ell _i\) and another task with origin \(o_j\) and fixed length \(\ell _j\), this paper shows how to systematically derive a formula \(F(\underline{o_j}, \overline{o_j}, \ell _i, \ell _j)\), where \(\underline{o_j}\) and \(\overline{o_j}\) resp...

For all 8192 combinations of Allen's 13 relations between one task with origin o i and fixed length i and another task with origin o j and fixed length j , we give a formula F(o j , o j , i , j), where o j and o j respectively denote the earliest and the latest origin of task j, evaluating to a set of integers which are infeasible for o i for the g...

La programmation par contraintes est une approche régulièrement utilisée pour traiter des problèmes d’ordonnancement variés. Les problèmes d’ordonnancement cumulatifs représentent une classe de problèmes dans laquelle des tâches non morcelable peuvent être effectuées en parallèle. Ces problèmes apparaissent dans de nombreux contextes réels, tels qu...

This paper is originally motivated by an application where the objective is to generate a video summary, built using intervals extracted from a video source. In this application, the constraints used to select the relevant pieces of intervals are based on Allen’s algebra. The best state-of-the-art results are obtained with a small set of ad hoc sol...

We investigate cumulative scheduling in uncertain environments, using constraint programming. We detail in this paper the dynamic sweep filtering algorithm of the FlexC global constraint.

Energetic Reasoning (ER) is a powerful filtering algorithm for the Cumulative constraint. Unfortunately, ER is generally too costly to be used in practice. One reason of its bad behavior is that many intervals are considered as relevant by the checker of ER, although most of them should be ignored. In this paper, we provide a sharp characterization...