Gobert, Maxime Vallee, Francois Gmys, Jan Melab, Nouredine Toubeau, Jean-François Tuyttens, Daniel

This paper presents a comparison between two surrogate-assisted optimization methods dealing with two-stage stochastic programming. The Efficient Global Optimization (EGO) framework is challenging a method coupling Genetic Algorithm (GA) and offline-learnt kriging model for the lower stage optimization. The objective is to prove the good behavior o...

Gupta, Siddharth Kosowski, Adrian Viennot, Laurent

For fixed $h \geq 2$, we consider the task of adding to a graph $G$ a set of weighted shortcut edges on the same vertex set, such that the length of a shortest $h$-hop path between any pair of vertices in the augmented graph is exactly the same as the original distance between these vertices in $G$. A set of shortcut edges with this property is cal...

Ducoffe, Guillaume

Given an n-vertex m-edge graph G with non-negative edge-weights, a shortest cycle of G is one minimizing the sum of the weights on its edges. The girth of G is the weight of such a shortest cycle. We obtain several new approximation algorithms for computing the girth of weighted graphs: For any graph G with polynomially bounded integer weights, we ...

Gupta, Siddharth Kosowski, Adrian Viennot, Laurent

For fixed $h \geq 2$, we consider the task of adding to a graph $G$ a set of weighted shortcut edges on the same vertex set, such that the length of a shortest $h$-hop path between any pair of vertices in the augmented graph is exactly the same as the original distance between these vertices in $G$. A set of shortcut edges with this property is cal...

Gupta, Siddharth Kosowski, Adrian Viennot, Laurent

For fixed $h \geq 2$, we consider the task of adding to a graph $G$ a set of weighted shortcut edges on the same vertex set, such that the length of a shortest $h$-hop path between any pair of vertices in the augmented graph is exactly the same as the original distance between these vertices in $G$. A set of shortcut edges with this property is cal...

Cohen-Addad, Vincent Li, Jason

We study the complexity of the classic capacitated k-median and k-means problems parameterized by the number of centers, k. These problems are notoriously difficult since the best known approximation bound for high dimensional Euclidean space and general metric space is Theta(log k) and it remains a major open problem whether a constant factor exis...

Bergé, Pierre Mouscadet, Benjamin Rimmel, Arpad Tomasik, Joanna

The parameterized complexity of counting minimum cuts stands as a natural question because Ball and Provan showed its #P-completeness. For any undirected graph $G=(V,E)$ and two disjoint sets of its vertices $S,T$, we design a fixed-parameter tractable algorithm which counts minimum edge $(S,T)$-cuts parameterized by their size $p$. Our algorithm o...

Daykin, J.W. Groult, R. Guesnet, Y. Lecroq, T. Lefebvre, A. Leonard, M. Mouchard, L. Prieur-Gaston, É. Watson, B.

A degenerate or indeterminate string on an alphabet Σ is a sequence of non-empty subsets of Σ. Given a degenerate string t of length n, we present a new method based on the Burrows--Wheeler transform for searching for a degenerate pattern of length m in t running in O(mn) time on a constant size alphabet Σ. Furthermore, it is a hybrid pattern-match...

Dantas, Cassio Cohen, Jérémy Gribonval, Rémi

Dictionary learning, paired with sparse coding, aims at providing sparse data representations. When dealing with large datasets, the dictionary obtained by applying unstructured dictionary learning methods may be of considerable size, posing both memory and computational complexity issues. We show how a previously proposed structured dictionary lea...

Daykin, J.W. Groult, R. Guesnet, Y. Lecroq, T. Lefebvre, A. Leonard, M. Mouchard, L. Prieur-Gaston, É. Watson, B.

A degenerate or indeterminate string on an alphabet Σ is a sequence of non-empty subsets of Σ. Given a degenerate string t of length n, we present a new method based on the Burrows--Wheeler transform for searching for a degenerate pattern of length m in t running in O(mn) time on a constant size alphabet Σ. Furthermore, it is a hybrid pattern-match...