Retour au site du LAAS-CNRS

Laboratoire d’analyse et d’architecture des systèmes

Publications de l'équipe ROC

Choisir la langue : FR | EN

639documents trouvés

18214
05/10/2018

Fuel-optimal impulsive fixed-time trajectories in the linearized circular restricted 3-body-problem

R.SERRA , D.ARZELIER, F.BREHARD, M.M.JOLDES

MAC, ROC

Manifestation avec acte : International Astronautical Congress ( IAC ) 2018 du 01 octobre au 05 octobre 2018, Breme (Allemagne), Octobre 2018, 9p. , N° 18214

Lien : https://hal.archives-ouvertes.fr/hal-01830253

Diffusable

Plus d'informations

Abstract

The problem of fixed-time fuel-optimal trajectories with high-thrust propulsion in the vicinity of a Lagrange point is tackled via the linear version of the primer vector theory. More precisely, the proximity to a Lagrange point i.e. any equilibrium point-stable or not-in the circular restricted three-body problem allows for a linearization of the dynamics. Furthermore, it is assumed that the spacecraft has ungimbaled thrusters, leading to a formulation of the cost function with the 1-norm for space coordinates, even though a generalization exists for steerable thrust and the 2-norm. In this context, the primer vector theory gives necessary and sufficient optimality conditions for admissible solutions to two-value boundary problems. Similarly to the case of rendezvous in the restricted two-body problem, the in-plane and out-of-plane trajectories being uncoupled, they can be treated independently. As a matter of fact, the out-of-plane dynamics is simple enough for the optimal control problem to be solved analytically via this indirect approach. As for the in-plane dynamics, the primer vector solution of the so-called primal problem is derived by solving a hierarchy of linear programs, as proposed recently for the aforementioned rendezvous. The optimal thrusting strategy is then numerically obtained from the necessary and sufficient conditions. Finally, in-plane and out-of-plane control laws are combined to form the complete 3-D fuel-optimal solution. Results are compared to the direct approach that consists in working on a discrete set of times in order to perform optimization in finite dimension. Examples are provided near various Lagrange points in the Sun-Earth and Earth-Moon systems, hinting at the extensive span of possible applications of this technique in station-keeping as well as mission analysis, for instance when connecting manifolds to achieve escape or capture.

144218
18163
01/09/2018

A Dial-a-Ride evaluation for solving the job-shop with routing considerations

M.GONDRAN, M.J.HUGUET, P.LACOMME, A.QUILLIOT, N.TCHERNEV

LIMOS, ROC

Revue Scientifique : Engineering Applications of Artificial Intelligence, Vol.74, pp.70-89, Septembre 2018 , N° 18163

Lien : https://hal.laas.fr/hal-01822071

Diffusable

Plus d'informations

Abstract

The Job-Shop scheduling Problem with Transport (JSPT) is a combinatorial optimization problem that combines both scheduling and routing problems. It has received attention for decades, resulting in numerous publications focused on the makespan minimization. The JSPT is commonly modeled by a disjunctive graph that encompasses both machine-operations and transport-operations. The transport-operations define a sub-problem which is close to the DARP where pickup and delivery operations have to be scheduled. The vast majority of the evaluation functions used into disjunctive graphs of JSPT, minimizes the makespan and there is no routing criteria in the objective function. Commonly used evaluation functions lead to left-shifted solutions for both machine-operations and transport-operations. The present work investigates a new evaluation function for the JSPT which integrates routing problematic to compute non semi-active solutions but which minimize the makespan first and maximize the Quality of Service second thanks to a time-lag max based modeling and an iterative process. The Quality of Service proposed in this paper, is extended from the Quality of Service defined by (Cordeau and Laporte, 2003) for the DARP. The procedure performance is benchmarked with a CPLEX resolution and the numerical experiments proved that the proposed evaluation function is nearly optimal and provides new solutions with a high Quality of Service.

143875
18213
29/06/2018

Mixed-integer and constraint programming formulations for a multi-skill project scheduling problem with partial preemption

O.POLO MEJIA, M.C.ANSELMET, C.ARTIGUES, P.LOPEZ

ROC, CEA Cadarache

Manifestation avec acte : International Conference on Modeling, Optimization & Simulation ( MOSIM ) 2018 du 27 juin au 29 juin 2018, Toulouse (France), Juin 2018, 8p. , N° 18213

Lien : https://hal.archives-ouvertes.fr/hal-01830739

Diffusable

Plus d'informations

Abstract

In this paper, we consider the weekly scheduling problem of activities within one of the research facilities of the French Alternative Energies and Atomic Energy Commission (CEA in short for French). To better represent this problem we propose a new variant of the multi-skill project scheduling problem (MSPSP) involving partial preemption. We describe the new MSPSP variant and we present two formulations for the problem: one using mixed-integer linear programming (MILP) and a second one using constraint programming (CP). Computational experiments on realistic data are carried out and discussed.

144216
18154
20/06/2018

GeoSafe – Evacuation planning problems

C.ARTIGUES, E.HEBRARD, Y.PENCOLE, A.SCHUTT, P.STUCKEY

ROC, DISCO, CSIRO, Univ of Melbourne

Rapport LAAS N°18154, Juin 2018, 10p.

Lien : https://hal.archives-ouvertes.fr/hal-01814177

Diffusable

Plus d'informations

Abstract

This paper aims at identifying new challenging variants of the evacuation planning problems, especially in case of bush fires, based on exchanges with practitioners in the context of the GeoSafe project. A large amount of work has been carried out at NICTA mainly in the context of floodings, which can be easily transposed to evacuation in case of fires. .We present a state-of-the-art review of these papers and we provide new research directions for the GeoSafe project.

143837
18153
20/06/2018

A Study of Evacuation Planning for Wildfires

C.ARTIGUES, E.HEBRARD, Y.PENCOLE, A.SCHUTT, P.STUCKEY

ROC, DISCO, CSIRO, Univ of Melbourne

Rapport LAAS N°18153, Juin 2018, 17p.

Lien : https://hal.archives-ouvertes.fr/hal-01814083

Diffusable

Plus d'informations

Abstract

The GEO-SAFE project gathers researchers and fire emergency practitioners from EU and Australia with the aim to design innovative models and efficient response tools based on optimization methods for fighting wildfires. In this paper, we consider an evacuation planning problem issued from discussions with practitioners, where a wildfire is threatening a region with intermediate populated centres. As in earlier approaches in case of flood, we use a constraint optimization model involving malleable tasks to represent the evacuation of a population and a cumulative constraint per route segments. Indeed, in order to mitigate congestion risks, the authorities may delay the start of the evacuation but they may also affect the rate of evacuation by modulating the method used to raise the alarm. However, we consider a different objective: we maximize the minimum " safety margin " , weighted by the population, over every road segment. We introduce a new heuristic and a global flow constraint propa-gator. Moreover, we also propose an instance generator based on a random generation of road networks and basic fire propagation models. This generator produces challenging benchmarks even with very few evacuation tasks. Finally, we report the results of extensive computational experiments done using CP Optimizer.

143836
18094
20/06/2018

SRide: A Privacy-Preserving Ridesharing System

U.M.AIVODJI, K.HUGUENIN, M.J.HUGUET, M.O.KILLIJIAN

TSF, HEC Lausanne, ROC

Manifestation avec acte : ACM Conference on Security and Privacy in Wireless and Mobile Networks ( WiSec ) 2018 du 18 juin au 20 juin 2018, Stockholm (Suède), Juin 2018 , N° 18094

Lien : https://hal.archives-ouvertes.fr/hal-01762436

Diffusable

143253
18155
20/06/2018

Data Instance generator and optimization models for evacuation planning in the event of wildfire

C.ARTIGUES, E.HEBRARD, Y.PENCOLE, A.SCHUTT, P.STUCKEY

ROC, DISCO, CSIRO, Univ of Melbourne

Rapport LAAS N°18155, Juin 2018, 18p.

Lien : https://hal.archives-ouvertes.fr/hal-01814063

Diffusable

Plus d'informations

Abstract

One critical part of decision support during the response phase to a wildfire is the ability to perform large-scale evacuation planning. While in practice most evacuation planning is principally designed by experts using simple heuristic approaches or scenario simulations, more recently optimization approaches to evacuation planning have been carried out, notably in the context of floodings. Evacuation planning in case of wildfires is much harder as wildfire propagations are inherently less predictable than floods. This paper present a new optimization model for evacuation planning in the event of wildfire aiming at maximizing the temporal safety margin between the evac-uees and the actual or potential wildfire front. As a first contribution, an open-source data instance generator based on road network generation via quadtrees and a basic fire propagation model is proposed to the community. As a second contribution we propose 0–1 integer programming and constraint programming formulations enhanced with a 1 simple compression heuristic that are compared on 240 problem instances build by the generator. The results show that the generated instances are computationally challenging and that the contraint programming framework obtains the best performance.

143838
18142
11/06/2018

Octal Games on Graphs: The game 0.33 on subdivided stars and bistars. Full proof of Theorem 22

L.BEAUDOU, P.COUPECHOUX, A.DAILLY, S.GRAVIER, J.MONCEL, A.PARREAU, E.SOPENA

UBP, ROC, LIRIS, UJF, LABRI

Rapport LAAS N°18142, Juin 2018, 16p.

Lien : https://hal.archives-ouvertes.fr/hal-01807116

Diffusable

Plus d'informations

Abstract

We give a full proof of Theorem 22 of "Octal Games on Graphs: The game 0.33 on subdivided stars and bistars".

143748
18120
22/05/2018

Optimal convergence rates for Nesterov acceleration

J.F.AUJOL, C.DOSSAL, A.RONDEPIERRE

IMB, IMT, Toulouse, ROC

Rapport LAAS N°18120, Mai 2018, 16p.

Lien : https://hal.archives-ouvertes.fr/hal-01786117

Diffusable

Plus d'informations

Abstract

In this paper, we study the behavior of solutions of the ODE associated to Nesterov acceleration. It is well-known since the pioneering work of Nesterov that the rate of convergence O(t 2) is optimal for the class of convex functions. In this work, we show that better convergence rates can be obtained with some additional geometrical conditions, such as Lojasiewicz property. More precisely, we prove the optimal convergence rates that can be obtained depending on the geometry of the function F to minimize. The convergence rates are new, and they shed new light on the behavior of Nesterov acceleration schemes.

143539
18098
20/04/2018

Multi-skill project scheduling in a nuclear research facility

O.POLO MEJIA, M.C.ANSELMET, C.ARTIGUES, P.LOPEZ

CEA Cadarache, ROC

Manifestation avec acte : International Conference on Project Management and Scheduling ( PMS ) 2018 du 17 avril au 20 avril 2018, Rome (Italie), Avril 2018 , N° 18098

Lien : https://hal-cea.archives-ouvertes.fr/cea-01780570

Diffusable

143333
Les informations recueillies font l’objet d’un traitement informatique destiné à des statistiques d'utilisation du formulaire de recherche dans la base de données des publications scientifiques. Les destinataires des données sont : le service de documentation du LAAS.Conformément à la loi « informatique et libertés » du 6 janvier 1978 modifiée en 2004, vous bénéficiez d’un droit d’accès et de rectification aux informations qui vous concernent, que vous pouvez exercer en vous adressant à
Pour recevoir une copie des documents, contacter doc@laas.fr en mentionnant le n° de rapport LAAS et votre adresse postale. Signalez tout problème de dysfonctionnement à sysadmin@laas.fr. http://www.laas.fr/pulman/pulman-isens/web/app.php/