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Michaël Clément Louis Ghislain Thémans

Publications associées (20)

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In this thesis, we focus on standard classes of problems in numerical optimization: unconstrained nonlinear optimization as well as systems of nonlinear equations. More precisely, we consider two types of unconstrained nonlinear optimization problems. On t ...

EPFL2007

A multi-iterate method to solve systems of nonlinear equations

Michel Bierlaire, Michaël Clément Louis Ghislain Thémans, Frank Crittin

We propose an extension of secant methods for nonlinear equations using a population of previous iterates. Contrarily to classical secant methods, where exact interpolation is used, we prefer a least squares approach to calibrate the linear model. We propo ...

2007

A heuristic for nonlinear global optimization relevant to discrete choice models estimation

Michel Bierlaire, Michaël Clément Louis Ghislain Thémans, Nicolas Zufferey

In most applications related to transportation, it is of major importance to be able to identify the global optimum of the associated optimization problem. The work we present in this paper is motivated by the optimization problems arising in the maximum l ...

2007

A heuristic for global nonlinear optimization

Michel Bierlaire, Michaël Clément Louis Ghislain Thémans, Nicolas Zufferey

The proposed heuristic combines a variable neighborhood search (VNS) framework with a local search performed by a trust-region algorithm. The curvature of the function is exploited to generate the neighborhoods. Numerical results illustrate an excellent be ...

2007

A heuristic for nonlinear global optimization

Michel Bierlaire, Michaël Clément Louis Ghislain Thémans, Nicolas Zufferey

We propose a new heuristic for nonlinear global optimization combining a variable neighborhood search framework with a modified trust-region algorithm as local search. The proposed method presents the capability to prematurely interrupt the local search if ...

2007

Solving singularity issues in the estimation of econometric models

Michel Bierlaire, Michaël Clément Louis Ghislain Thémans

Econometric models play an important role in transportation analysis. Estimating more and more complex models becomes problematic. The associated log-likelihood function is highly nonlinear and non concave and the comlexity of the model requires constraint ...

2006

Dealing with singularities in nonlinear unconstrained optimization

Michel Bierlaire, Michaël Clément Louis Ghislain Thémans

We propose new trust-region based optimization algorithms for solving unconstrained nonlinear problems whose second derivatives matrix is singular at a local solution. We give a theoretical characterization of the singularity in this context and we propose ...

2006

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2006

Analysis of driver's response to real-time information in Switzerland

Michel Bierlaire, Michaël Clément Louis Ghislain Thémans

We present behavioral models designed to capture the response of drivers to real-time traffic information. In 2003, we have conducted a survey in Switzerland in order to collect both Revealed Preferences (RP) and Stated Preferences (SP) about choice decisi ...

2006

STRC 20062006