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Barra V.,University Blaise Pascal | Barra V.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems | Biasotti S.,CNR Institute for Applied Mathematics and Information Technologies
Pattern Recognition | Year: 2013

3D shape retrieval is becoming an acute issue for numerous applications that span from CAD to serious games to biomedicine and all contexts where it is fundamental to automatically retrieve geometric information from a collection of 3D models. This paper addresses 3D shape retrieval in terms of a graph-based description and the definition of a corresponding similarity measure. For this purpose, 3D models are represented as bags of shortest paths defined over well chosen Extended Reeb Graphs, while the similarity between pairs of Extended Reeb Graphs is addressed through kernels adapted to these descriptions. Results are comparable with the best results of the literature, and the modularity and evolutivity of the method ensure its applicability to other problems, from partial shape matching to classification. © 2013 Elsevier Ltd.


Roustant O.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems | Ginsbourger D.,University of Bern
Journal of Statistical Software | Year: 2012

We present two recently released R packages, DiceKriging and DiceOptim, for the approximation and the optimization of expensive-to-evaluate deterministic functions. Following a self-contained mini tutorial on Kriging-based approximation and optimization, the functionalities of both packages are detailed and demonstrated in two distinct sections. In particular, the versatility of DiceKriging with respect to trend and noise specifications, covariance parameter estimation, as well as conditional and unconditional simulations are illustrated on the basis of several reproducible numerical experiments. We then put to the fore the implementation of sequential and parallel optimization strategies relying on the expected improvement criterion on the occasion of DiceOptim's presentation. An appendix is dedicated to complementary mathematical and computational details.


Jaziri F.,Clermont University | Jaziri F.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems | Jaziri F.,CNRS Microorganisms Laboratory: Genome and Environment
Database : the journal of biological databases and curation | Year: 2014

In recent years, high-throughput molecular tools have led to an exponential growth of available 16S rRNA gene sequences. Incorporating such data, molecular tools based on target-probe hybridization were developed to monitor microbial communities within complex environments. Unfortunately, only a few 16S rRNA gene-targeted probe collections were described. Here, we present PhylOPDb, an online resource for a comprehensive phylogenetic oligonucleotide probe database. PhylOPDb provides a convivial and easy-to-use web interface to browse both regular and explorative 16S rRNA-targeted probes. Such probes set or subset could be used to globally monitor known and unknown prokaryotic communities through various techniques including DNA microarrays, polymerase chain reaction (PCR), fluorescent in situ hybridization (FISH), targeted gene capture or in silico rapid sequence identification. PhylOPDb contains 74 003 25-mer probes targeting 2178 genera including Bacteria and Archaea. Database URL: http://g2im.u-clermont1.fr/phylopdb/


Gerard Y.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

The main task of the paper is to investigate the question of the recognition of digital polyhedra with a fixed number of facets: given a finite lattice set S ⊂ ℤd and an integer n, does there exist a polyhedron P of ℝd with n facets and P ∩ ℤd = S? The problem can be stated in terms of polyhedral separation of the set S and its complementary Sc = ℤd/S. The difficulty is that the set Sc is not finite. It makes the classical algorithms intractable for this purpose. This problem is overcome by introducing a partial order “is in the shadow of”. Its minimal lattice elements are called the jewels. The main result of the paper is within the domain of the geometry of numbers: under some assumptions on the lattice set S (if S ⊂ ℤ2 is not degenerated or if the interior of the convex hull of S ⊂ ℤd contains an integer point), it has only a finite number of lattice jewels. In this case, we provide an algorithm of recognition of a digital polyhedron with n facets which always finishes. © Springer International Publishing Switzerland 2016.


Duhamel C.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems | Lacomme P.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems | Quilliot A.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems | Toussaint H.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems
Computers and Operations Research | Year: 2011

This paper addresses an extension of the capacitated vehicle routing problem where customer demand is composed of two-dimensional weighted items (2L-CVRP). The objective consists in designing a set of trips minimizing the total transportation cost with a homogenous fleet of vehicles based on a depot node. Items in each vehicle trip must satisfy the two-dimensional orthogonal packing constraints. A GRASP×ELS algorithm is proposed to compute solutions of a simpler problem in which the loading constraints are transformed into resource constrained project scheduling problem (RCPSP) constraints. We denote this relaxed problem RCPSP-CVRP. The optimization framework deals with RCPSP-CVRP and lastly RCPSP-CVRP solutions are transformed into 2L-CVRP solutions by solving a dedicated packing problem. The effectiveness of our approach is demonstrated through computational experiments including both classical CVRP and 2L-CVRP instances. Numerical experiments show that the GRASP×ELS approach outperforms all previously published methods. © 2010 Elsevier Ltd. All rights reserved.


Duhamel C.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems | Lacomme P.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems | Prins C.,University of Technology of Troyes | Prodhon C.,University of Technology of Troyes
Computers and Operations Research | Year: 2010

This paper addresses the capacitated location-routing problem (CLRP), raised by distribution networks involving depot location, fleet assignment and routing decisions. The CLRP is defined by a set of potential depot locations, with opening costs and limited capacities, a homogeneous fleet of vehicles, and a set of customers with known demands. The objective is to open a subset of depots, to assign customers to these depots and to design vehicle routes, in order to minimize both the cost of open depots and the total cost of the routes. The proposed solution method is a greedy randomized adaptive search procedure (GRASP), calling an evolutionary local search (ELS) and searching within two solution spaces: giant tours without trip delimiters and true CLRP solutions. Giant tours are evaluated via a splitting procedure that minimizes the total cost subject to vehicle capacity, fleet size and depot capacities. This framework is benchmarked on classical instances. Numerical experiments show that the approach outperforms all previously published methods and provides numerous new best solutions. © 2009 Elsevier Ltd. All rights reserved.


Duhamel C.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems | Lacomme P.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems | Prodhon C.,CNRS Risk Management Science and Technology
Engineering Applications of Artificial Intelligence | Year: 2012

Routing Problems have been deeply studied over the last decades. Split procedures have proved their efficiency for those problems, especially within global optimization frameworks. The purpose is to build a feasible routing solution by splitting a giant tour into trips. This is done by computing a shortest path on an auxiliary graph built from the giant tour. One of the latest advances consists in handling extra resource constraints through the generation of labels on the nodes of the auxiliary graph. Lately, the development of a new generic split family based on a Depth First Search (DFS) approach during label generation has highlighted the efficiency of this new method for the routing problems, through extensive numerical evaluations on the location-routing problem. In this paper, we present a hybrid Evolutionary Local Search (hybrid ELS) for non-homogeneous fleet Vehicle Routing Problems (VRP) based on the application of split strategies. Experiments show our method is able to handle all known benchmarks, from Vehicle Fleet Mix Problems to Heterogeneous Fleet VRP (HVRP). We also propose a set of new realistic HVRP instances from 50 to more than 250 nodes coming from French counties. It relies on real distances in kilometers between towns. Since many classical HVRP instance sets are solved to optimality, this new set of instances could allow a fair comparative study of methods. The DFS split strategy shows its efficiency and attests the fact that it can be a promising line of research for routing problems including numerous additional constraints. © 2011 Elsevier Ltd. All rights reserved.


Torres L.M.,National Polytechnic School of Ecuador | Wagler A.K.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems
RAIRO - Operations Research | Year: 2013

To model the dynamics of discrete deterministic systems, we extend the Petri nets framework by a priority relation between conflicting transitions, which is encoded by orienting the edges of a transition conflict graph. The aim of this paper is to gain some insight into the structure of this conflict graph and to characterize a class of suitable orientations by an analysis in the context of hypergraph theory. © EDP Sciences, ROADEF, SMAI 2013.


Mouelhi-Chibani W.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems | Pierreval H.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems
Computers and Industrial Engineering | Year: 2010

Dispatching rules are often suggested to schedule manufacturing systems in real-time. Numerous dispatching rules exist. Unfortunately no dispatching rule (DR) is known to be globally better than any other. Their efficiency depends on the characteristics of the system, operating condition parameters and the production objectives. Several authors have demonstrated the benefits of changing dynamically these rules, so as to take into account the changes that can occur in the system state. A new approach based on neural networks (NN) is proposed here to select in real time, each time a resource becomes available, the most suited DR. The selection is made in accordance with the current system state and the workshop operating condition parameters. Contrarily to the few learning approaches presented in the literature to select scheduling heuristics, no training set is needed. The NN parameters are determined through simulation optimization. The benefits of the proposed approach are illustrated through the example of a simplified flow-shop already published. It is shown that the NN can automatically select efficient DRs dynamically: the knowledge is only generated from simulation experiments, which are driven by the optimization method. Once trained offline, the resulting NN can be used online, in connection with the monitoring system of a flexible manufacturing system. © 2009 Elsevier Ltd. All rights reserved.


Laforest C.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems | Phan R.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems
RAIRO - Operations Research | Year: 2013

In this paper we present a new approach to solve the Minimum Independent Dominating Set problem in general graphs which is one of the hardest optimization problem. We propose a method using a clique partition of the graph, partition that can be obtained greedily. We provide conditions under which our method has a better complexity than the complexity of the previously known algorithms. Based on our theoretical method, we design in the second part of this paper an efficient algorithm by including cuts in the search process. We then experiment it and show that it is able to solve almost all instances up to 50 vertices in reasonable time and some instances up to several hundreds of vertices. To go further and to treat larger graphs, we analyze a greedy heuristic. We show that it often gives good (sometimes optimal) results in large instances up to 60 000 vertices in less than 20 s. That sort of heuristic is a good approach to get an initial solution for our exact method. We also describe and analyze some of its worst cases. © 2013 EDP Sciences, ROADEF, SMAI.

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