Publications de Grégory François

Publications associées (42)

A Directional Modifier-Adaptation Algorithm for Real-Time Optimization

Dominique Bonvin, Grégory François, Sean Costello

The steady advances of computational methods make model-based optimization an increasingly attractive method for process improvement. Unfortunately, the available models are often inaccurate. The traditional remedy is to update the model parameters, but th ...

Elsevier2016

Real-Time Optimization: Optimizing the Operation of Energy Systems in the Presence of Uncertainty and Disturbances

Dominique Bonvin, Grégory François

In practice, the quest for the optimal operation of energy systems is complicated by the simultaneous presence of operating constraints, among which the need for producing the power required by the user, and of uncertainty. The latter concept incorporates ...

2014

On the Use of Transient Information for Static Real-Time Optimization

Dominique Bonvin, Grégory François, Alejandro Gabriel Marchetti

Optimal operation of chemical processes is key for meeting productivity, quality, safety and environmental objectives. Both model-based and data-driven schemes are used to compute optimal operating conditions [1]: - The model-based techniques are intu ...

2015

From Discrete Measurements to Bounded Gradient Estimates: A Look at Some Regularizing Structures

Dominique Bonvin, Grégory François, Gene Bunin

Obtaining a reliable gradient estimate for an unknown function when given only its discrete measurements is a common problem in many engineering disciplines. While there are many approaches to obtaining an estimate of a gradient, obtaining lower and upper ...

American Chemical Society2013

Optimal service pricing for a cloud cache

Anastasia Ailamaki, Grégory François

Cloud applications that offer data management services are emerging. Such clouds support caching of data in order to provide quality query services. The users can query the cloud data, paying the price for the infrastructure they use. Cloud management nece ...

2011

Use of Transient Measurements for Static Real-Time Optimization

Dominique Bonvin, Grégory François, Alejandro Gabriel Marchetti, Tafarel de Avila Ferreira

Modifier adaptation (MA) is a real-time optimization (RTO) method characterized by its ability to enforce plant optimality upon convergence despite the presence of model uncertainty. The approach is based on correcting the available model using gradient es ...

2017

Modifier Adaptation for Constrained Closed-Loop Systems

Dominique Bonvin, Grégory François, Alejandro Gabriel Marchetti, Sean Costello

The steady advance of computational methods makes model-based optimization an increasingly attractive method for process improvement. Unfortunately, the available models are often inaccurate. An iterative optimization method called "modifier adaptation" ov ...

2014

Use of Transient Measurements for the Optimization of Steady-State Performance via Modifier Adaptation

Dominique Bonvin, Grégory François

Real-time optimization (RTO) methods use measurements to offset the effect of uncertainty and drive the plant to optimality. RTO schemes differ in the way measurements are incorporated in the optimization framework. Explicit RTO schemes solve a static opti ...

American Chemical Society2014

Optimal service pricing for a cloud cache

Anastasia Ailamaki, Grégory François

Cloud applications that offer data management services are emerging. Such clouds support caching of data in order to provide quality query services. The users can query the cloud data, paying the price for the infrastructure they use. Cloud management nece ...

Institute of Electrical and Electronics Engineers2011

Dynamic optimization of batch emulsion polymerization using simulated annealing

Grégory François

The aim of this paper is to present a global approach to dynamic optimization of batch emulsion polymerization reactors using a stochastic optimizer. The objective is to minimize the final batch time with constraints on the final conversion and molecular w ...

2004

Real-Time Optimization for Kites

Dominique Bonvin, Grégory François, Sean Costello

Over the past decade, a large number of academics and start-ups have devoted them- selves to developing kites, or airplanes on tethers, as a renewable energy source. Determining the trajectories the kite should follow is a modeling and optimization challen ...

2013

A Globally Convergent Algorithm for the Run-to-Run Control of Systems with Sector Nonlinearities

Dominique Bonvin, Grégory François

Run-to-run control is a technique that exploits the repetitive nature of processes to iteratively adjust the inputs and drive the run-end outputs to their reference values. It can be used to control both static and finite-time dynamic systems. Although the ...

American Chemical Society2011

Two-Layered Real-Time Optimization of a Solid Oxide Fuel Cell Stack

Dominique Bonvin, Grégory François, Gene Bunin

The optimal operation of a solid oxide fuel cell stack is addressed in this paper. Real-time optimization, performed at a slow time scale via constraint adaptation, is used to account for uncertainty and degradation eﬀects, while model-predictive control i ...

2010

Measurement-based run-to-run optimization of batch processes : application to industrial acrylamide copolymerization

Grégory François

In batch chemical processing, dynamic optimization is the method of choice to reduce production costs while satisfying safety constraints and product specifications. Most of the standard optimization techniques are based on a model of the process, while it ...

EPFL2004

Crosswind Kite Control - A Benchmark Problem for Advanced Control and Dynamic Optimization

Dominique Bonvin, Grégory François, Sean Costello

This article presents a kite control and optimization problem intended as a benchmark problem for advanced control and optimization. We provide an entry point to this exciting renewable energy system for researchers in control and optimization methods look ...

Wiley-Blackwell2017

Experimental Real-Time Optimization of a Solid Oxide Fuel Cell Stack via Constraint Adaptation

Dominique Bonvin, Grégory François, Zacharie Wuillemin, Arata Nakajo, Gene Bunin, Leonidas Tsikonis

The experimental validation of a real-time optimization (RTO) strategy for the optimal operation of a solid oxide fuel cell (SOFC) stack is reported in this paper. Unlike many existing studies, the RTO approach presented here utilizes the constraint-adapta ...

2010

Equivalence between Neighboring-Extremal Control and Self-Optimizing Control for the Steady-State Optimization of Dynamical Systems

Dominique Bonvin, Grégory François

The problem of steering a dynamical system toward optimal steady-state performance is considered. For this purpose, a static optimization problem can be formulated and solved. However, because of uncertainty, the optimal steady-state inputs can rarely be a ...

American Chemical Society2014

Modifier Adaptation for Run-to-Run Optimization of Transient Processes

Dominique Bonvin, Grégory François, Sean Costello

Dynamic optimization can be used to determine optimal input profiles for dynamic processes. Due to plant-model mismatch and disturbances, the optimal inputs determined through model-based optimization will, in general, not be optimal for the plant. Modifie ...

2011

Use of Convex Model Approximations for Real-Time Optimization via Modifier Adaptation

Dominique Bonvin, Grégory François

Real-Time Optimization (RTO) via modifier adaptation is a class of methods for which measurements are used to iteratively adapt the model via input-affine additive terms. The modifier terms correspond to the deviations between the measured and predicted co ...

American Chemical Society2013

Application of Real-Time Optimization Methods to Energy Systems in the Presence of Uncertainties and Disturbances

Dominique Bonvin, Grégory François, Sean Costello

In practice, the quest for the optimal operation of energy systems is complicated by the presence of operating constraints, which includes the need to produce the power required by the user, and by the need to account for uncertainty. The latter concept in ...

2015