Concept

Largeur arborescente

Publications associées (32)

An introduction to treewidth

The notion of treewidth has seen to be a powerful vehicle for many graph algorithmic studies. A lot of problems, which are in general

NP

-complete, can be solved in polynomial time for graphs with small treewidth. In the first part of this paper we presen ...

2006

Tree-Based Pursuit: Algorithm and Properties

Pascal Frossard, Pierre Vandergheynst, Philippe Jost

This paper proposes a tree-based pursuit algorithm that efficiently trades off complexity and approximation performance for overcomplete signal expansions. Finding the sparsest representation of a signal using a redundant dictionary is, in general, a NP-Ha ...

2006

Tree-Based Pursuit: Algorithm and Properties

Pascal Frossard, Pierre Vandergheynst, Philippe Jost

2005

Similarity analysis of the subsurface ﬂow response of hillslopes with complex geometry

Alexis Berne

The matter of the efficient and parsimonious parameterization of hillslope subsurface flow remains an important issue in catchment hydrological studies (Brutsaert, 1995). Insights into the influence of the shape and hydraulic characteristics of hillslopes ...

2005

Travel time distributions of subsurface flow along complex hillslopes with exponential width functions

Alexis Berne

Recently, Troch et al. [10] introduced the hillslope-storage Boussinesq (hsB) equation to describe subsurface flow and saturation along complex hillslopes. They demonstrated that numerical solutions of the hsB equation account explicitly for plan shape of ...

2004

Image compression with learnt tree-structured dictionaries

Pierre Vandergheynst, Gianluca Monaci, Philippe Jost

In the present paper we propose a new framework for the construction of meaningful dictionaries for sparse representation of signals. The dictionary approach to coding and compression proves very attractive since decomposing a signal over a redundant set o ...

2004

Magnetophotoluminescence of GaN/AlxGa1-xN quantum wells: Valence band reordering and excitonic binding energies

Nicolas Grandjean

A reordered valence band in GaN/AlxGa1-xN quantum wells with respect to GaN epilayers has been found as a result of the observation of an enhanced g factor (g*similar to3) in magnetoluminescence spectra in fields up to 55 T. This has been caused by a rever ...

2001

Parametric and kinetic minimum spanning trees

Monika Henzinger

We consider the parametric minimum spanning tree problem, in which we are given a graph with edge weights that are linear functions of a parameter, and wish to computethe sequence of minimum spanning trees generated as, varies. We also consider the kinetic ...

IEEE Comp Soc1998

Quantum confined Stark effect due to built-in internal polarization fields in (Al,Ga)N/GaN quantum wells

Nicolas Grandjean

(Al,Ga)N/GaN quantum wells have been studied by temperature-dependent luminescence and reflectivity. The samples were grown by molecular beam epitaxy on (0001) sapphire substrates, and well widths were varied from 3 to 15 monolayers (ML's) with a 2-ML incr ...

1998

ORIGIN OF THE BLUE-SHIFT OBSERVED IN HIGHLY STRAINED (GA,IN)AS QUANTUM-WELLS GROWN ON GAAS(001) VICINAL SURFACES

Nicolas Grandjean, Christophe Lopez

The photoluminescence energy of strained (Ga, In)As quantum wells grown on (001) GaAs slightly misoriented (2 degrees-6 degrees) towards (111)A exhibits a blue shift when compared to quantum wells grown on perfectly oriented substrates. It is shown that th ...

1995

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An introduction to treewidth

Bernard Ries, Daniela Bronner

The notion of treewidth has seen to be a powerful vehicle for many graph algorithmic studies. A lot of problems, which are in general

NP

-complete, can be solved in polynomial time for graphs with small treewidth. In the first part of this paper we presen ...

2006