%% hal-00760097, version 1
%% http://hal.archives-ouvertes.fr/hal-00760097
@article{verel:hal-00760097,
    hal_id = {hal-00760097},
    url = {http://hal.archives-ouvertes.fr/hal-00760097},
    title = {{On the structure of multiobjective combinatorial search space: MNK-landscapes with correlated objectives}},
    author = {Verel, S{\'e}bastien and Liefooghe, Arnaud and Jourdan, Laetitia and Dhaenens, Clarisse},
    abstract = {{The structure of the search space explains the behavior of multiobjective search algorithms, and helps to design well-performing approaches. In this work, we analyze the properties of multiobjective combinatorial search spaces, and we pay a particular attention to the correlation between the objective functions. To do so, we extend the multiobjective NK-landscapes in order to take the objective correlation into account. We study the co-influence of the problem dimension, the degree of non-linearity, the number of objectives, and the objective correlation on the structure of the Pareto optimal set, in terms of cardinality and number of supported solutions, as well as on the number of Pareto local optima. This work concludes with guidelines for the design of multiobjective local search algorithms, based on the main fitness landscape features.}},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , DOLPHIN - INRIA Lille - Nord Europe , Laboratoire d'Informatique Fondamentale de Lille - LIFL},
    pages = {to appear},
    journal = {European Journal of Operational Research},
    audience = {internationale },
    doi = {10.1016/j.ejor.2012.12.019 },
    year = {2013},
    month = Jan,
}

%% hal-00563462, version 1
%% http://hal.archives-ouvertes.fr/hal-00563462
@article{vanneschi:hal-00563462,
    hal_id = {hal-00563462},
    url = {http://hal.archives-ouvertes.fr/hal-00563462},
    title = {{A Study of Neutrality of Boolean Function Landscapes in Genetic Programming}},
    author = {Vanneschi, Leonardo and Pirola, Yuri and Mauri, Giancarlo and Collard, Philippe and Verel, S{\'e}bastien},
    abstract = {{Neutrality of genetic programming Boolean function landscapes is investigated in this paper. Compared with some well known contributions on the same issue, we define new measures that help characterizing neutral landscapes, we use a new sampling methodology, which captures features that are disregarded by uniform random sampling, we introduce new genetic operators to define the neighborhood of tree structures and we compare the fitness landscape induced by different sets of functional operators. This study indicates the existence of a relationship between our neutrality measures and the performance of genetic programming for the problems studied.}},
    language = {Anglais},
    affiliation = {Dipartimento di Informatica Sistemistica e Comunicazione - DISCo , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , DOLPHIN - INRIA Lille - Nord Europe},
    pages = {34 -- 57},
    journal = {Journal of Theoretical Computer Science (TCS)},
    volume = {425},
    audience = {internationale },
    doi = {10.1016/j.tcs.2011.03.011 },
    year = {2012},
    month = Mar,
}

%% hal-00563461, version 1
%% http://hal.archives-ouvertes.fr/hal-00563461
@article{daolio:hal-00563461,
    hal_id = {hal-00563461},
    url = {http://hal.archives-ouvertes.fr/hal-00563461},
    title = {{Communities of Minima in Local Optima Networks of Combinatorial Spaces}},
    author = {Daolio, Fabio and Tomassini, Marco and Verel, S{\'e}bastien and Ochoa, Gabriela},
    abstract = {{In this work we present a new methodology to study the structure of the configuration spaces of hard combinatorial problems. It consists in building the network that has as nodes the locally optimal configurations and as edges the weighted oriented transitions between their basins of attraction. We apply the approach to the detection of communities in the optima networks produced by two different classes of instances of a hard combinatorial optimization problem: the quadratic assignment problem (QAP). We provide evidence indicating that the two problem instance classes give rise to very different configuration spaces. For the so-called real-like class, the networks possess a clear modular structure, while the optima networks belonging to the class of random uniform instances are less well partitionable into clusters. This is convincingly supported by using several statistical tests. Finally, we shortly discuss the consequences of the findings for heuristically searching the corresponding problem spaces.}},
    language = {Anglais},
    affiliation = {Institut des syst{\`e}mes d'information - ISI , DOLPHIN - INRIA Lille - Nord Europe , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , School of Computer Science},
    pages = {1684 - 1694},
    journal = {Physica A: Statistical Mechanics and its Applications},
    volume = {390},
    number = {9 },
    audience = {internationale },
    year = {2011},
    month = Jul,
    pdf = {http://hal.archives-ouvertes.fr/hal-00563461/PDF/QAPcommunities.pdf},
}

%% hal-00488637, version 1
%% http://hal.archives-ouvertes.fr/hal-00488637
@article{verel:hal-00488637,
    hal_id = {hal-00488637},
    url = {http://hal.archives-ouvertes.fr/hal-00488637},
    title = {{Local Optima Networks of NK Landscapes with Neutrality}},
    author = {Verel, S{\'e}bastien and Ochoa, Gabriela and Tomassini, Marco},
    abstract = {{In previous work we have introduced a network-based model that abstracts many details of the underlying landscape and compresses the landscape information into a weighted, oriented graph which we call the local optima network. The vertices of this graph are the local optima of the given fitness landscape, while the arcs are transition probabilities between local optima basins. Here we extend this formalism to neutral fitness landscapes, which are common in difficult combinatorial search spaces. By using two known neutral variants of the NK family (i.e. NKp and NKq) in which the amount of neutrality can be tuned by a parameter, we show that our new definitions of the optima networks and the associated basins are consistent with the previous definitions for the non-neutral case. Moreover, our empirical study and statistical analysis show that the features of neutral landscapes interpolate smoothly between landscapes with maximum neutrality and non-neutral ones. We found some unknown structural differences between the two studied families of neutral landscapes. But overall, the network features studied confirmed that neutrality, in landscapes with percolating neutral networks, may enhance heuristic search. Our current methodology requires the exhaustive enumeration of the underlying search space. Therefore, sampling techniques should be developed before this analysis can have practical implications. We argue, however, that the proposed model offers a new perspective into the problem difficulty of combinatorial optimization problems and may inspire the design of more effective search heuristics.}},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , DOLPHIN - INRIA Lille - Nord Europe , School of Computer Science , Institut des syst{\`e}mes d'information - ISI},
    pages = {783 - 797},
    journal = {IEEE Transactions on Evolutionary Computation},
    volume = {volume 14},
    number = {6 },
    audience = {internationale },
    collaboration = {scobi team },
    year = {2010},
    month = Nov,
    pdf = {http://hal.archives-ouvertes.fr/hal-00488637/PDF/NKneutral.pdf},
}

%% hal-00354804, version 1
%% http://hal.archives-ouvertes.fr/hal-00354804
@article{tomassini:hal-00354804,
    hal_id = {hal-00354804},
    url = {http://hal.archives-ouvertes.fr/hal-00354804},
    title = {{Complex-network analysis of combinatorial spaces: The NK landscape case}},
    author = {Tomassini, Marco and Verel, S{\'e}bastien and Ochoa, Gabriela},
    abstract = {{We propose a network characterization of combinatorial fitness landscapes by adapting the notion of inherent networks proposed for energy surfaces. We use the well-known family of NK landscapes as an example. In our case the inherent network is the graph whose vertices represent the local maxima in the landscape, and the edges account for the transition probabilities between their corresponding basins of attraction. We exhaustively extracted such networks on representative NK landscape instances, and performed a statistical characterization of their properties. We found that most of these network properties are related to the search difficulty on the underlying NK landscapes with varying values of K.}},
    keywords = {complex networks ; graph theory ; probability ; optimisation},
    language = {Anglais},
    affiliation = {Institut des syst{\`e}mes d'information - ISI , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , School of Computer Science},
    pages = {066114},
    journal = {Physical Review E: Statistical, Nonlinear, and Soft Matter Physics},
    volume = {78},
    number = {6 },
    audience = {internationale },
    collaboration = {university of Lausannes ; university of Nothingham },
    doi = {10.1103/PhysRevE.78.066114 },
    year = {2008},
    month = Dec,
    pdf = {http://hal.archives-ouvertes.fr/hal-00354804/PDF/NKlandscapes-DS.pdf},
}

%% hal-00164772, version 1
%% http://hal.archives-ouvertes.fr/hal-00164772
@article{verel:hal-00164772,
    hal_id = {hal-00164772},
    url = {http://hal.archives-ouvertes.fr/hal-00164772},
    title = {{Fitness landscape of the cellular automata majority problem: View from the Olympus}},
    author = {Verel, S{\'e}bastien and Collard, Philippe and Tomassini, Marco and Vanneschi, Leonardo},
    abstract = {{In this paper we study cellular automata (CAs) that perform the computational Majority task. This task is a good example of what the phenomenon of emergence in complex systems is. We take an interest in the reasons that make this particular fitness landscape a difficult one. The first goal is to study the landscape as such, and thus it is ideally independent from the actual heuristics used to search the space. However, a second goal is to understand the features a good search technique for this particular problem space should possess. We statistically quantify in various ways the degree of difficulty of searching this landscape. Due to neutrality, investigations based on sampling techniques on the whole landscape are difficult to conduct. So, we go exploring the landscape from the top. Although it has been proved that no CA can perform the task perfectly, several efficient CAs for this task have been found. Exploiting similarities between these CAs and symmetries in the landscape, we define the Olympus landscape which is regarded as the ''heavenly home'' of the best local optima known (blok). Then we measure several properties of this subspace. Although it is easier to find relevant CAs in this subspace than in the overall landscape, there are structural reasons that prevent a searcher from finding overfitted CAs in the Olympus. Finally, we study dynamics and performance of genetic algorithms on the Olympus in order to confirm our analysis and to find efficient CAs for the Majority problem with low computational cost.}},
    keywords = {cellular automata ; evolutionary computation ; genetic algorithm ; fitness landscapes ; neutrality ; correlation analysis},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , Institut des syst{\`e}mes d'information - ISI , Dipartimento di Informatica Sistemistica e Comunicazione - DISCo},
    pages = {54-77},
    journal = {Theoretical Computer Science},
    volume = {378},
    number = {1 },
    note = {tea team tea team },
    audience = {internationale },
    doi = {10.1016/j.tcs.2007.01.001 },
    year = {2007},
    month = Jun,
    pdf = {http://hal.archives-ouvertes.fr/hal-00164772/PDF/ca-fit-landsc\_final.pdf},
}

%% hal-00164699, version 1
%% http://hal.archives-ouvertes.fr/hal-00164699
@article{verel:hal-00164699,
    hal_id = {hal-00164699},
    url = {http://hal.archives-ouvertes.fr/hal-00164699},
    title = {{Neutralit{\'e} dans les paysages de fitness. {\'E}volution artificielle et neutralit{\'e}}},
    author = {Verel, S{\'e}bastien and Collard, Philippe and Clergue, Manuel},
    abstract = {{Evolutionary algorithms (EA) are optimization algorithms inspired by the neo-dar winian theory of evolution. Those algorithms use a population of potential solutions which is gradually guided towards better solutions discovered by random variation. The neutral theory of evolution considers that the majority of mutations are selectively neutral or lethal. In this article we present the main results about neutral theory in the context of EA, and particulary how this theory affects studies of fitness landscapes. Fitness landscapes represent the set of potential solutions of a problem as an space equipped with a neighborhood relation and where the solutions have an height corresponding to their performance. This article will show academic and real problems related to neutral landscapes and the nature of EA dynamics on those landscapes. In order to improve the performances of EA, we then present technics based on the choice of redundant coding, just as the design of EA exploiting neutrality.}},
    keywords = {evolutionary computation ; fitness landscapes ; neutrality ; hardness},
    language = {Fran{\c c}ais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis - I3S},
    pages = {1023-1048},
    journal = {Revue Technique et Science Informatiques},
    volume = {25},
    number = {8 - 9 },
    note = {tea team tea team },
    audience = {non sp{\'e}cifi{\'e}e },
    year = {2006},
    month = Dec,
}

%% hal-00383711, version 1
%% http://hal.archives-ouvertes.fr/hal-00383711
@inproceedings{bercachi:hal-00383711,
    hal_id = {hal-00383711},
    url = {http://hal.archives-ouvertes.fr/hal-00383711},
    title = {{Do not Choose Representation just Change: An Experimental Study in States based EA}},
    author = {Bercachi, Maroun and Collard, Philippe and Clergue, Manuel and Verel, Sebastien},
    abstract = {{Our aim in this paper is to analyse the phenotypic effects (evolvability) of diverse coding conversion operators in an instance of the states based evolutionary algorithm (SEA). Since the representation of solutions or the selection of the best encoding during the optimization process has been proved to be very important for the efficiency of evolutionary algorithms (EAs), we will discuss a strategy of coupling more than one representation and different procedures of conversion from one coding to another during the search. Elsewhere, some EAs try to use multiple representations (SM-GA, SEA, etc.) in intention to benefit from the characteristics of each of them. In spite of those results, this paper shows that the change of the representation is also a crucial approach to take into consideration while attempting to increase the performances of such EAs. As a demonstrative example, we use a two states SEA (2-SEA) which has two identical search spaces but different coding conversion operators. The results show that the way of changing from one coding to another and not only the choice of the best representation nor the representation itself is very advantageous and must be taken into account in order to well-desing and improve EAs execution.}},
    keywords = {States based Evolutionary Algorithm, Representation, Coding Coupling, Coding Conversion. Algorithms, Performance, Experimentation. G.1.6 [Mathematics of Computing]: Numerical Analysis Optimization [Stochastic Programming]; I.2.8 [Computing Methodologies]: Artificial Intelligence Problem Solving, ControlMethods, and Search [Heuristic Methods]},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI},
    booktitle = {{Genetic and Evolutionary Computation Conference 2009}},
    address = {Montr{\'e}al, Canada},
    volume = {1},
    number = {1 },
    audience = {internationale },
    collaboration = {States based Evolutionary Algorithm },
    year = {2009},
    month = Jul,
    pdf = {http://hal.archives-ouvertes.fr/hal-00383711/PDF/GECCO2009.pdf},
}

%% hal-00741842, version 1
%% http://hal.archives-ouvertes.fr/hal-00741842
@inproceedings{chicano:hal-00741842,
    hal_id = {hal-00741842},
    url = {http://hal.archives-ouvertes.fr/hal-00741842},
    title = {{Local Optima Networks, Landscape Autocorrelation and Heuristic Search Performance}},
    author = {Chicano, Francisco and Daolio, Fabio and Ochoa, Gabriela and Verel, S{\'e}bastien and Tomassini, Marco and Alba, Enrique},
    abstract = {{Recent developments in fitness landscape analysis include the study of Local Optima Networks (LON) and applications of the Elementary Landscapes theory. This paper represents a first step at combining these two tools to explore their ability to forecast the performance of search algorithms. We base our analysis on the Quadratic Assignment Problem (QAP) and conduct a large statistical study over 600 generated instances of different types. Our results reveal interesting links between the network measures, the autocorrelation measures and the performance of heuristic search algorithms.}},
    language = {Anglais},
    affiliation = {E.T.S. Ingenierıa Informatica , Institut des syst{\`e}mes d'information - ISI , School of Computer Science , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , DOLPHIN - INRIA Lille - Nord Europe},
    booktitle = {{Parallel Problem Solving from Nature - PPSN XII}},
    publisher = {Springer Berlin Heidelberg},
    pages = {337-347},
    address = {Taormina, Italie},
    volume = {7492},
    editor = {Coello, CarlosA.Coello and Cutello, Vincenzo and Deb, Kalyanmoy and Forrest, Stephanie and Nicosia, Giuseppe and Pavone, Mario },
    series = {Lecture Notes in Computer Science },
    audience = {internationale },
    doi = {10.1007/978-3-642-32964-7\_34 },
    year = {2012},
    month = Sep,
    pdf = {http://hal.archives-ouvertes.fr/hal-00741842/PDF/QAPLON.pdf},
}

%% hal-00741725, version 1
%% http://hal.archives-ouvertes.fr/hal-00741725
@inproceedings{daolio:hal-00741725,
    hal_id = {hal-00741725},
    url = {http://hal.archives-ouvertes.fr/hal-00741725},
    title = {{Local optima networks and the performance of iterated local search}},
    author = {Daolio, Fabio and Verel, S{\'e}bastien and Ochoa, Gabriela and Tomassini, Marco},
    abstract = {{Local Optima Networks (LONs) have been recently proposed as an alternative model of combinatorial fitness landscapes. The model compresses the information given by the whole search space into a smaller mathematical object that is the graph having as vertices the local optima and as edges the possible weighted transitions between them. A new set of metrics can be derived from this model that capture the distribution and connectivity of the local optima in the underlying configuration space. This paper departs from the descriptive analysis of local optima networks, and actively studies the correlation between network features and the performance of a local search heuristic. The NK family of landscapes and the Iterated Local Search metaheuristic are considered. With a statistically-sound approach based on multiple linear regression, it is shown that some LONs' features strongly influence and can even partly predict the performance of a heuristic search algorithm. This study validates the expressive power of LONs as a model of combinatorial fitness landscapes.}},
    keywords = {combinatorial fitness landscape, local optima network, local search heuristics},
    language = {Anglais},
    affiliation = {Institut des syst{\`e}mes d'information - ISI , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , DOLPHIN - INRIA Lille - Nord Europe , School of Computer Science},
    booktitle = {{Proceedings of the fourteenth international conference on Genetic and evolutionary computation conference}},
    publisher = {ACM},
    pages = {369-376},
    address = {Philadelphia, {\'E}tats-Unis},
    audience = {internationale },
    doi = {10.1145/2330163.2330217 },
    year = {2012},
    pdf = {http://hal.archives-ouvertes.fr/hal-00741725/PDF/gecco12-verel.pdf},
}

%% hal-00744887, version 1
%% http://hal.archives-ouvertes.fr/hal-00744887
@inproceedings{verel:hal-00744887,
    hal_id = {hal-00744887},
    url = {http://hal.archives-ouvertes.fr/hal-00744887},
    title = {{Fitness landscapes and graphs: multimodularity, ruggedness and neutrality}},
    author = {Verel, S{\'e}bastien},
    abstract = {{One of the most commonly-used metaphors to describe the process of heuristic search methods in solving combinatorial optimization problems is that of a fitness landscape. The landscape metaphor appears most commonly in work related to evolutionary algorithms, however, it can be used for search in general; the search space can be regarded as a spatial structure where each point (solution) has a height (objective function value) forming a landscape surface. In this scenario, the search process would be an adaptive-walk over a landscape that can range from having many peaks of high fitness flanked by cliffs falling to profound valleys of low fitness, to being smooth, with low hills and gentle valleys. Combinatorial landscapes can be seen as a graph whose vertices are the possible configurations. If two configurations can be transformed into each other by a suitable operator move, then we can trace an edge between them. The resulting graph, with an indication of the fitness at each vertex, is a representation of the given problem fitness landscape. The study of the fitness landscape consists in analyzing this graph or a relevant partition of it, with respect to the search dynamics or problem difficulty. This advanced tutorial will give an overview of the origins of the fitness landscape metaphor, and will cover the alternative ways to define fitness landscapes in evolutionary computation. The two main geometries: multimodal and neutral landscapes, which correspond to two different graph partitions found in combinatorial optimization, will be considered, as well as the dynamics of metaheurhistics searching on them. Furthermore, the relationship between problem hardness and fitness landscape metrics (i.e. autocorrelation, fitness distance correlation, neutral degree, etc), and the local optima network properties, studied in recent work, will be deeply analyzed. Finally, the tutorial will conclude with a brief survey of open questions and recent research directions on fitness landscapes.}},
    keywords = {fitness landscape, graph, multimodal, network, neutrality},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , DOLPHIN - INRIA Lille - Nord Europe},
    booktitle = {{Proceedings of the fourteenth international conference on Genetic and evolutionary computation conference companion}},
    publisher = {ACM},
    pages = {1013--1034},
    address = {Philadelphia, {\'E}tats-Unis},
    audience = {internationale },
    doi = {10.1145/2330784.2330927 },
    year = {2012},
}

%% hal-00639522, version 1
%% http://hal.archives-ouvertes.fr/hal-00639522
@inproceedings{verel:hal-00639522,
    hal_id = {hal-00639522},
    url = {http://hal.archives-ouvertes.fr/hal-00639522},
    title = {{Local Optima Networks with Escape Edges}},
    author = {Verel, S{\'e}bastien and Daolio, Fabio and Ochoa, Gabriela and Tomassini, Marco},
    abstract = {{This paper proposes an alternative definition of edges (escape edges) for the recently introduced network-based model of combinatorial landscapes: Local Optima Networks (LON). The model compresses the information given by the whole search space into a smaller mathematical object that is the graph having as vertices the local optima and as edges the possible weighted transitions between them. The original definition of edges accounted for the notion of transitions between the basins of attraction of local optima. This definition, although informative, produced densely connected networks and required the exhaustive sampling of the basins of attraction. The alternative escape edges proposed here do not require a full computation of the basins. Instead, they account for the chances of escaping a local optima after a controlled mutation (e.g. 1 or 2 bit-flips) followed by hill-climbing. A statistical analysis comparing the two LON models for a set of NK landscapes, is presented and discussed. Moreover, a preliminary study is presented, which aims at validating the LON models as a tool for analyzing the dynamics of stochastic local search in combinatorial optimization.}},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , DOLPHIN - INRIA Lille - Nord Europe , Institut des syst{\`e}mes d'information - ISI , School of Computer Science},
    booktitle = {{Procedings of International Conference on Artificial Evolution (EA-2011)}},
    pages = {10 - 23},
    address = {Angers, France},
    audience = {internationale },
    collaboration = {scobi team },
    year = {2011},
    month = Oct,
    pdf = {http://hal.archives-ouvertes.fr/hal-00639522/PDF/LonEscapeEA2011.pdf},
}

%% hal-00579993, version 1
%% http://hal.archives-ouvertes.fr/hal-00579993
@inproceedings{derbel:hal-00579993,
    hal_id = {hal-00579993},
    url = {http://hal.archives-ouvertes.fr/hal-00579993},
    title = {{DAMS: Distributed Adaptive Metaheuristic Selection}},
    author = {Derbel, Bilel and Verel, S{\'e}bastien},
    abstract = {{We present a distributed generic algorithm called DAMS dedicated to adaptive optimization in distributed environments. Given a set of metaheuristic, the goal of DAMS is to coordinate their local execution on distributed nodes in order to optimize the global performance of the distributed system. DAMS is based on three-layer architecture allowing node to decide distributively what local information to communicate, and what metaheuristic to apply while the optimization process is in progress. The adaptive features of DAMS are first addressed in a very general setting. A specific DAMS called SBM is then described and analyzed from both a parallel and an adaptive point of view. SBM is a simple, yet efficient, adaptive distributed algorithm using an exploitation component allowing nodes to select the metaheuristic with the best locally observed performance, and an exploration component allowing nodes to detect the metaheuristic with the actual best performance. The efficiency of BSM-DAMS is demonstrated through experimentations and comparisons with other adaptive strategies (sequential and distributed).}},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique Fondamentale de Lille - LIFL , DOLPHIN - INRIA Lille - Nord Europe , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI},
    booktitle = {{Proceedings of the 13th annual conference on Genetic and evolutionary computation}},
    publisher = {ACM},
    pages = {1955--1962},
    address = {Dublin, Irlande},
    audience = {internationale },
    doi = {10.1145/2001576.2001839 },
    year = {2011},
    month = Jul,
    pdf = {http://hal.archives-ouvertes.fr/hal-00579993/PDF/fp495-derbel.pdf},
}

%% hal-00579990, version 1
%% http://hal.archives-ouvertes.fr/hal-00579990
@inproceedings{marmion:hal-00579990,
    hal_id = {hal-00579990},
    url = {http://hal.archives-ouvertes.fr/hal-00579990},
    title = {{The Road to VEGAS: Guiding the Search over Neutral Networks}},
    author = {Marmion, Marie-Eleonore and Dhaenens, Clarisse and Jourdan, Laetitia and Liefooghe, Arnaud and Verel, S{\'e}bastien},
    abstract = {{VEGAS (Varying Evolvability-Guided Adaptive Search) is a new methodology proposed to deal with the neutrality property of some optimization problems. ts main feature is to consider the whole neutral network rather than an arbitrary solution. Moreover, VEGAS is designed to escape from plateaus based on the evolvability of solution and a multi-armed bandit. Experiments are conducted on NK-landscapes with neutrality. Results show the importance of considering the whole neutral network and of guiding the search cleverly. The impact of the level of neutrality and of the exploration-exploitation trade-off are deeply analyzed.}},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique Fondamentale de Lille - LIFL , DOLPHIN - INRIA Lille - Nord Europe , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI},
    booktitle = {{Proceedings of the 13th annual conference on Genetic and evolutionary computation}},
    publisher = {ACM},
    pages = {1979--1986},
    address = {Dublin, Irlande},
    audience = {internationale },
    doi = {10.1145/2001576.2001842 },
    year = {2011},
    month = Jul,
    pdf = {http://hal.archives-ouvertes.fr/hal-00579990/PDF/fp668-marmion.pdf},
}

%% hal-00579984, version 1
%% http://hal.archives-ouvertes.fr/hal-00579984
@inproceedings{verel:hal-00579984,
    hal_id = {hal-00579984},
    url = {http://hal.archives-ouvertes.fr/hal-00579984},
    title = {{Set-based Multiobjective Fitness Landscapes: A Preliminary Study}},
    author = {Verel, S{\'e}bastien and Liefooghe, Arnaud and Dhaenens, Clarisse},
    abstract = {{Fitness landscape analysis aims to understand the geometry of a given optimization problem in order to design more efficient search algorithms. However, there is a very little knowledge on the landscape of multiobjective problems. In this work, following a recent proposal by Zitzler et al. (2010), we consider multiobjective optimization as a set problem. Then, we give a general definition of set-based multiobjective fitness landscapes. An experimental set-based fitness landscape analysis is conducted on the multiobjective NK-landscapes with objective correlation. The aim is to adapt and to enhance the comprehensive design of set-based multiobjective search approaches, motivated by an a priori analysis of the corresponding set problem properties.}},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , DOLPHIN - INRIA Lille - Nord Europe , Laboratoire d'Informatique Fondamentale de Lille - LIFL},
    booktitle = {{Proceedings of the 13th annual conference on Genetic and evolutionary computation}},
    publisher = {ACM},
    pages = {769--776},
    address = {Dublin, Irlande},
    audience = {internationale },
    doi = {10.1145/2001576.2001681 },
    year = {2011},
    month = Jul,
    pdf = {http://hal.archives-ouvertes.fr/hal-00579984/PDF/fp584-verel.pdf},
}

%% hal-00563459, version 1
%% http://hal.archives-ouvertes.fr/hal-00563459
@inproceedings{marmion:hal-00563459,
    hal_id = {hal-00563459},
    url = {http://hal.archives-ouvertes.fr/hal-00563459},
    title = {{NILS: a Neutrality-based Iterated Local Search and its application to Flowshop Scheduling}},
    author = {Marmion, Marie-Eleonore and Dhaenens, Clarisse and Jourdan, Laetitia and Liefooghe, Arnaud and Verel, S{\'e}bastien},
    abstract = {{This paper presents a new methodology that exploits specific characteristics from the fitness landscape. In particular, we are interested in the property of neutrality, that deals with the fact that the same fitness value is assigned to numerous solutions from the search space. Many combinatorial optimization problems share this property, that is generally very inhibiting for local search algorithms. A neutrality-based iterated local search, that allows neutral walks to move on the plateaus, is proposed and experimented on a permutation flowshop scheduling problem with the aim of minimizing the makespan. Our experiments show that the proposed approach is able to find improving solutions compared with a classical iterated local search. Moreover, the tradeoff between the exploitation of neutrality and the exploration of new parts of the search space is deeply analyzed.}},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique Fondamentale de Lille - LIFL , DOLPHIN - INRIA Lille - Nord Europe , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI},
    booktitle = {{Evolutionary Computation in Combinatorial Optimization}},
    publisher = {Springer},
    pages = {191--202},
    address = {Turino, Italie},
    volume = {6622},
    editor = {Peter Merz and Jin-Kao Hao },
    series = {Lecture Notes in Computer Science },
    audience = {internationale },
    year = {2011},
    month = Apr,
    pdf = {http://hal.archives-ouvertes.fr/hal-00563459/PDF/marmion.pdf},
}

%% hal-00563460, version 1
%% http://hal.archives-ouvertes.fr/hal-00563460
@inproceedings{verel:hal-00563460,
    hal_id = {hal-00563460},
    url = {http://hal.archives-ouvertes.fr/hal-00563460},
    title = {{Pareto Local Optima of Multiobjective NK-Landscapes with Correlated Objectives}},
    author = {Verel, S{\'e}bastien and Liefooghe, Arnaud and Jourdan, Laetitia and Dhaenens, Clarisse},
    abstract = {{In this paper, we conduct a fitness landscape analysis for multiobjective combinatorial optimization, based on the local optima of multiobjective NK-landscapes with objective correlation. In single-objective optimization, it has become clear that local optima have a strong impact on the performance of metaheuristics. Here, we propose an extension to the multiobjective case, based on the Pareto dominance. We study the co-influence of the problem dimension, the degree of non-linearity, the number of objectives and the correlation degree between objective functions on the number of Pareto local optima.}},
    language = {Anglais},
    affiliation = {DOLPHIN - INRIA Lille - Nord Europe , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , Laboratoire d'Informatique Fondamentale de Lille - LIFL},
    booktitle = {{Evolutionary Computation in Combinatorial Optimization}},
    publisher = {Springer},
    pages = {226--237},
    address = {Turino, Italie},
    volume = {6622},
    editor = {Peter Merz and Jin-Kao Hao },
    series = {Lecture Notes in Computer Science },
    audience = {internationale },
    year = {2011},
    month = Apr,
    pdf = {http://hal.archives-ouvertes.fr/hal-00563460/PDF/verel.pdf},
}

%% hal-00550356, version 1
%% http://hal.archives-ouvertes.fr/hal-00550356
@inproceedings{marmion:hal-00550356,
    hal_id = {hal-00550356},
    url = {http://hal.archives-ouvertes.fr/hal-00550356},
    title = {{On the Neutrality of Flowshop Scheduling Fitness Landscapes}},
    author = {Marmion, Marie-Eleonore and Dhaenens, Clarisse and Jourdan, Laetitia and Liefooghe, Arnaud and Verel, S{\'e}bastien},
    abstract = {{Solving efficiently complex problems using metaheuristics, and in particular local searches, requires incorporating knowledge about the problem to solve. In this paper, the permutation flowshop problem is studied. It is well known that in such problems, several solutions may have the same fitness value. As this neutrality property is an important one, it should be taken into account during the design of optimization methods. Then in the context of the permutation flowshop, a deep landscape analysis focused on the neutrality property is driven and propositions on the way to use this neutrality to guide efficiently the search are given.}},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique Fondamentale de Lille - LIFL , DOLPHIN - INRIA Lille - Nord Europe , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI},
    booktitle = {{Proceedings of Learning and Intelligent OptimizatioN Conference (LION 5), LNCS}},
    publisher = {Springer},
    pages = {238--252},
    address = {Rome, Italie},
    volume = {6683/2011},
    audience = {internationale },
    doi = {10.1007/978-3-642-25566-3\_18 },
    year = {2011},
    month = Feb,
    pdf = {http://hal.archives-ouvertes.fr/hal-00550356/PDF/Marmion.pdf},
}

%% hal-00550355, version 1
%% http://hal.archives-ouvertes.fr/hal-00550355
@inproceedings{ochoa:hal-00550355,
    hal_id = {hal-00550355},
    url = {http://hal.archives-ouvertes.fr/hal-00550355},
    title = {{Clustering of Local Optima in Combinatorial Fitness Landscapes}},
    author = {Ochoa, Gabriela and Verel, S{\'e}bastien and Daolio, Fabio and Tomassini, Marco},
    abstract = {{Using the recently proposed model of combinatorial landscapes: local optima networks, we study the distribution of local optima in two classes of instances of the quadratic assignment problem. Our results indicate that the two problem instance classes give rise to very different configuration spaces. For the so-called real-like class, the optima networks possess a clear modular structure, while the networks belonging to the class of random uniform instances are less well partitionable into clusters. We briefly discuss the consequences of the findings for heuristically searching the corresponding problem spaces.}},
    language = {Anglais},
    affiliation = {School of Computer Science , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , DOLPHIN - INRIA Lille - Nord Europe , Institut des syst{\`e}mes d'information - ISI},
    booktitle = {{LNCS}},
    publisher = {Springer},
    pages = {454--457},
    address = {Rome, Italie},
    volume = {6683/2011},
    audience = {internationale },
    doi = {10.1007/978-3-642-25566-3\_35 },
    year = {2011},
    month = Feb,
    pdf = {http://hal.archives-ouvertes.fr/hal-00550355/PDF/lion2011.pdf},
}

%% hal-00550349, version 1
%% http://hal.archives-ouvertes.fr/hal-00550349
@inproceedings{verel:hal-00550349,
    hal_id = {hal-00550349},
    url = {http://hal.archives-ouvertes.fr/hal-00550349},
    title = {{Analyzing the Effect of Objective Correlation on the Efficient Set of MNK-Landscapes}},
    author = {Verel, S{\'e}bastien and Liefooghe, Arnaud and Jourdan, Laetitia and Dhaenens, Clarisse},
    abstract = {{In multiobjective combinatorial optimization, there exists two main classes of metaheuristics, based either on multiple aggregations, or on a dominance relation. As in the single objective case, the structure of the search space can explain the difficulty for multiobjective metaheuristics, and guide the design of such methods. In this work we analyze the properties of multiobjective combinatorial search spaces. In particular, we focus on the features related the efficient set, and we pay a particular attention to the correlation between objectives. Few benchmark takes such objective correlation into account. Here, we define a general method to design multiobjective problems with correlation. As an example, we extend the well-known multiobjective NK-landscapes. By measuring different properties of the search space, we show the importance of considering the objective correlation on the design of metaheuristics.}},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , DOLPHIN - INRIA Lille - Nord Europe , Laboratoire d'Informatique Fondamentale de Lille - LIFL},
    booktitle = {{Lecture Notes in Computer Science (LNCS)}},
    publisher = {Springer},
    pages = {116-130},
    address = {Rome, Italie},
    volume = {6683/2011},
    editor = {C.A. Coello Coello },
    series = {Lecture Notes in Computer Science (LNCS) },
    audience = {internationale },
    doi = {10.1007/978-3-642-25566-3\_9 },
    year = {2011},
    month = Feb,
    pdf = {http://hal.archives-ouvertes.fr/hal-00550349/PDF/verel.pdf},
}

%% hal-00550353, version 1
%% http://hal.archives-ouvertes.fr/hal-00550353
@inproceedings{verel:hal-00550353,
    hal_id = {hal-00550353},
    url = {http://hal.archives-ouvertes.fr/hal-00550353},
    title = {{On the Effect of Connectedness for Biobjective Multiple and Long Path Problems}},
    author = {Verel, S{\'e}bastien and Liefooghe, Arnaud and Humeau, J{\'e}r{\'e}mie and Jourdan, Laetitia and Dhaenens, Clarisse},
    abstract = {{Recently, the property of connectedness has been claimed to give a strong motivation on the design of local search techniques for multiobjective combinatorial optimization (MOCO). Indeed, when connectedness holds, a basic Pareto local search, initialized with at least one non-dominated solution, allows to identify the efficient set exhaustively. However, this becomes quickly infeasible in practice as the number of efficient solutions typically grows exponentially with the instance size. As a consequence, we generally have to deal with a limited-size approximation, where a good sample set has to be found. In this paper, we propose the biobjective multiple and long path problems to show experimentally that, on the first problems, even if the efficient set is connected, a local search may be outperformed by a simple evolutionary algorithm in the sampling of the efficient set. At the opposite, on the second problems, a local search algorithm may successfully approximate a disconnected efficient set. Then, we argue that connectedness is not the single property to study for the design of local search heuristics for MOCO. This work opens new discussions on a proper definition of the multiobjective fitness landscape.}},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , DOLPHIN - INRIA Lille - Nord Europe , Laboratoire d'Informatique Fondamentale de Lille - LIFL , UR Informatique Automatique},
    booktitle = {{Lecture Note in Computer Science (LNSC)}},
    publisher = {Springer},
    pages = {31--45},
    address = {Rome, Italie},
    volume = {6683},
    editor = {C.A. Coello Coello },
    audience = {internationale },
    year = {2011},
    month = Feb,
    pdf = {http://hal.archives-ouvertes.fr/hal-00550353/PDF/verel.pdf},
}

%% hal-00488401, version 1
%% http://hal.archives-ouvertes.fr/hal-00488401
@inproceedings{ochoa:hal-00488401,
    hal_id = {hal-00488401},
    url = {http://hal.archives-ouvertes.fr/hal-00488401},
    title = {{First-improvement vs. Best-improvement Local Optima Networks of NK Landscapes}},
    author = {Ochoa, Gabriela and Verel, S{\'e}bastien and Tomassini, Marco},
    abstract = {{This paper extends a recently proposed model for combinatorial landscapes: Local Optima Networks (LON), to incorporate a first-improvement (greedy-ascent) hill-climbing algorithm, instead of a best-improvement (steepest-ascent) one, for the definition and extraction of the basins of attraction of the landscape optima. A statistical analysis comparing best and first improvement network models for a set of NK landscapes, is presented and discussed. Our results suggest structural differences between the two models with respect to both the network connectivity, and the nature of the basins of attraction. The impact of these differences in the behavior of search heuristics based on first and best improvement local search is thoroughly discussed.}},
    language = {Anglais},
    affiliation = {School of Computer Science , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , DOLPHIN - INRIA Lille - Nord Europe , Institut des syst{\`e}mes d'information - ISI},
    booktitle = {{Proceedings of the 11th International Conference on Parallel Problem Solving From Nature}},
    pages = {104 - 113},
    address = {Krakow, Pologne},
    audience = {internationale },
    collaboration = {scobi team },
    year = {2010},
    month = Sep,
    pdf = {http://hal.archives-ouvertes.fr/hal-00488401/PDF/FirstImprLON.pdf},
}

%% hal-00487806, version 1
%% http://hal.archives-ouvertes.fr/hal-00487806
@inproceedings{daolio:hal-00487806,
    hal_id = {hal-00487806},
    url = {http://hal.archives-ouvertes.fr/hal-00487806},
    title = {{Local Optima Networks of the Quadratic Assignment Problem}},
    author = {Daolio, Fabio and Verel, S{\'e}bastien and Ochoa, Gabriela and Tomassini, Marco},
    abstract = {{Using a recently proposed model for combinatorial landscapes, Local Optima Networks (LON), we conduct a thorough analysis of two types of instances of the Quadratic Assignment Problem (QAP). This network model is a reduction of the landscape in which the nodes correspond to the local optima, and the edges account for the notion of adjacency between their basins of attraction. The model was inspired by the notion of 'inherent network' of potential energy surfaces proposed in physical-chemistry. The local optima networks extracted from the so called uniform and real-like QAP instances, show features clearly distinguishing these two types of instances. Apart from a clear confirmation that the search difficulty increases with the problem dimension, the analysis provides new confirming evidence explaining why the real-like instances are easier to solve exactly using heuristic search, while the uniform instances are easier to solve approximately. Although the local optima network model is still under development, we argue that it provides a novel view of combinatorial landscapes, opening up the possibilities for new analytical tools and understanding of problem difficulty in combinatorial optimization.}},
    language = {Anglais},
    affiliation = {Institut des syst{\`e}mes d'information - ISI , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , DOLPHIN - INRIA Lille - Nord Europe , School of Computer Science},
    booktitle = {{proceeding of IEEE world conference on computational intelligence (WCCI)}},
    pages = {3145 - 3152},
    address = {Barcelona, Espagne},
    audience = {internationale },
    collaboration = {scobi team },
    year = {2010},
    month = Jul,
    pdf = {http://hal.archives-ouvertes.fr/hal-00487806/PDF/LON-QAP-CEC2010.pdf},
}

%% hal-00460448, version 1
%% http://hal.archives-ouvertes.fr/hal-00460448
@inproceedings{verel:hal-00460448,
    hal_id = {hal-00460448},
    url = {http://hal.archives-ouvertes.fr/hal-00460448},
    title = {{Fitness landscapes and graphs: multimodularity, ruggedness and neutrality}},
    author = {Verel, S{\'e}bastien and Ochoa, Gabriela},
    abstract = {{One of the most commonly-used metaphors to describe the process of heuristic search methods in solving combinatorial optimisation problems is that of a fitness landscape. The landscape metaphor appears most commonly in work related to evolutionary algorithms, however, it can be used for search in general; the search space can be regarded as a spatial structure where each point (solution) has a height (objective function value) forming a landscape surface. In this scenario, the search process would be an adaptive-walk over a landscape that can range from having many peaks of high fitness flanked by cliffs falling to profound valleys of low fitness, to being smooth, with low hills and gentle valleys. Combinatorial landscapes can be seen as a graph whose vertices are the possible configurations. If two configurations can be transformed into each other by a suitable operator move, then we can trace an edge between them. The resulting graph, with an indication of the fitness at each vertex, is a representation of the given problem fitness landscape. The study of the fitness landscape consists in analysing this graph or a relevant partition of it, with respect to the search dynamics or problem difficulty. This advanced tutorial will give an overview of the origins of the fitness landscape metaphor, and will cover the alternative ways to define fitness landscapes in evolutionary computation. The two main geometries: multimodal and neutral landscapes, which correspond to two different graph partitions found in combinatorial optimization, will be considered, as well as the dynamics of methaurhistics searching on them. Furthermore, the relationship between problem hardness and fitness landscape metrics (i.e. autocorrelation, fitness distance correlation, neutral degree, etc), and the local optima network properties, studied in recent work, will be deeply analysed. Finally, the tutorial will conclude with a brief survey of open questions and recent research directions on fitness landscapes.}},
    keywords = {evolutionary computation ; fitness landscapes},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , DOLPHIN - INRIA Lille - Nord Europe , School of Computer Science},
    booktitle = {{WCCI 2010 : IEEE world congress on computational intelligence (CEC 2010)}},
    publisher = {IEEE},
    pages = {3593--3656},
    address = {Barcelona, Espagne},
    audience = {internationale },
    collaboration = {scobi team },
    year = {2010},
    month = Jul,
}

%% hal-00410191, version 1
%% http://hal.archives-ouvertes.fr/hal-00410191
@inproceedings{simoncini:hal-00410191,
    hal_id = {hal-00410191},
    url = {http://hal.archives-ouvertes.fr/hal-00410191},
    title = {{Centric selection: a way to tune the exploration/exploitation trade-off}},
    author = {Simoncini, David and Verel, S{\'e}bastien and Collard, Philippe and Clergue, Manuel},
    abstract = {{In this paper, we study the exploration / exploitation trade-off in cellular genetic algorithms. We define a new selection scheme, the centric selection, which is tunable and allows controlling the selective pressure with a single parameter. The equilibrium model is used to study the influence of the centric selection on the selective pressure and a new model which takes into account problem dependent statistics and selective pressure in order to deal with the exploration / exploitation trade-off is proposed: the punctuated equilibria model. Performances on the quadratic assignment problem and NK-Landscapes put in evidence an optimal exploration / exploitation trade-off on both of the classes of problems. The punctuated equilibria model is used to explain these results.}},
    keywords = {evolutionary computation ; cellular evolutionary computation},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI},
    booktitle = {{GECCO '09: Proceedings of the 11th Annual conference on Genetic and evolutionary computation}},
    publisher = {ACM},
    pages = {891--898},
    address = {Montreal, Canada},
    audience = {internationale },
    collaboration = {tea team },
    doi = {10.1145/1569901.1570023 },
    year = {2009},
    month = Jul,
    pdf = {http://hal.archives-ouvertes.fr/hal-00410191/PDF/centricCGA.pdf},
}

%% hal-00410186, version 1
%% http://hal.archives-ouvertes.fr/hal-00410186
@inproceedings{verel:hal-00410186,
    hal_id = {hal-00410186},
    url = {http://hal.archives-ouvertes.fr/hal-00410186},
    title = {{Fitness landscapes and graphs: multimodularity, ruggedness and neutrality}},
    author = {Verel, S{\'e}bastien},
    abstract = {{The performances of evolutionary algorithms (genetics algorithms, genetic programming, etc.) or local search algotihms (Simulated annealing, tabu search, etc.) depends on the properties of seach space structure. One concept to analyse the search space is the fitness landscapes in which the problem to optimize and the search algorithm are taken into account. The fitness landscape is a graph where the nodes are the potential solutions. The study of the fitness landscape consists in analysing this graph or a relevant partition of this graph according to the dynamic or search difficulty. This tutorial will give an overview, after an historical review of concept of fitness landscape, of the different ways to define fitness landscape in the field of evolutionary computation. Following, the two mains geometries (multimodal and neutral landscapes) corresponding to two different partitions of the graph, meets in optimization problems and the dynamics of metaheuristics on these will be given. The relationship between problems difficulty and fitness landscapes measures (autocorrelation, FDC, neutral degree, etc.) or the properties of the local optima networks, studied in recent work, will be deeply analysed. Finally, the tutorial will conclude with a brief survey of open questions and the recent researchs on fitness landscapes.}},
    keywords = {evolutionary computation ; fitness landscapes},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI},
    booktitle = {{GECCO '09: Proceedings of the 11th annual conference companion on Genetic and evolutionary computation conference}},
    publisher = {ACM},
    pages = {3593--3656},
    address = {Montreal, Canada},
    audience = {internationale },
    collaboration = {tea team },
    doi = {10.1145/1570256.1570431 },
    year = {2009},
    month = Jul,
}

%% hal-00403029, version 1
%% http://hal.archives-ouvertes.fr/hal-00403029
@inproceedings{vanneschi:hal-00403029,
    hal_id = {hal-00403029},
    url = {http://hal.archives-ouvertes.fr/hal-00403029},
    title = {{NK landscapes difficulty and Negative Slope Coefficient: How Sampling Influences the Results}},
    author = {Vanneschi, Leonardo and Verel, S{\'e}bastien and Collard, Philippe and Tomassini, Marco},
    abstract = {{Negative Slope Coefficient is an indicator of problem hardness that has been introduced in 2004 and that has returned promising results on a large set of problems. It is based on the concept of fitness cloud and works by partitioning the cloud into a number of bins representing as many different regions of the fitness landscape. The measure is calculated by joining the bins centroids by segments and summing all their negative slopes. In this paper, for the first time, we point out a potential problem of the Negative Slope Coefficient: we study its value for different instances of the well known NK-landscapes and we show how this indicator is dramatically influenced by the minimum number of points contained into a bin. Successively, we formally justify this behavior of the Negative Slope Coefficient and we discuss pros and cons of this measure.}},
    language = {Anglais},
    affiliation = {Dipartimento di Informatica Sistemistica e Comunicazione - DISCo , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , Institut des syst{\`e}mes d'information - ISI},
    booktitle = {{LNCS}},
    publisher = {Springer},
    pages = {100-110},
    address = {Tubingen, Allemagne},
    series = {LNCS },
    audience = {internationale },
    year = {2009},
    month = Apr,
    pdf = {http://hal.archives-ouvertes.fr/hal-00403029/PDF/centricCGA.pdf},
}

%% hal-00331864, version 1
%% http://hal.archives-ouvertes.fr/hal-00331864
@inproceedings{verel:hal-00331864,
    hal_id = {hal-00331864},
    url = {http://hal.archives-ouvertes.fr/hal-00331864},
    title = {{The Connectivity of NK Landscapes' Basins: A Network Analysis}},
    author = {Verel, S{\'e}bastien and Ochoa, Gabriela and Tomassini, Marco},
    abstract = {{We propose a network characterization of combinatorial fitness landscapes by adapting the notion of inherent networks proposed for energy surfaces. We use the well-known family of NK landscapes as an example. In our case the inherent network is the graph where the vertices represent the local maxima in the landscape, and the edges account for the transition probabilities between their corresponding basins of attraction. We exhaustively extracted such networks on representative small NK landscape instances, and performed a statistical characterization of their properties. We found that most of these network properties can be related to the search difficulty on the underlying NK landscapes with varying values of K.}},
    keywords = {Landscape Analysis ; Network Analysis ; Complex Networks ; Local Optima ; NK Landscapes},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , School of Computer Science , Institut des syst{\`e}mes d'information - ISI},
    booktitle = {{Proceedings of the Eleventh International Conference on the Simulation and Synthesis of Living Systems}},
    publisher = {MIT Press, Cambridge, MA},
    pages = {648-655},
    address = {Winchester, France},
    editor = {S. Bullock, J. Noble, R. Watson, and M. A. Bedau },
    note = {tea team tea team },
    audience = {internationale },
    collaboration = {university of Lausannes ; university of Nothingham },
    year = {2008},
    month = Aug,
    pdf = {http://hal.archives-ouvertes.fr/hal-00331864/PDF/VerelOchoaTomassiniNKNetworks.pdf},
}

%% hal-00331868, version 1
%% http://hal.archives-ouvertes.fr/hal-00331868
@inproceedings{ochoa:hal-00331868,
    hal_id = {hal-00331868},
    url = {http://hal.archives-ouvertes.fr/hal-00331868},
    title = {{A Study of NK Landscapes' Basins and Local Optima Networks}},
    author = {Ochoa, Gabriela and Tomassini, Marco and Verel, S{\'e}bastien and Darabos, Christian},
    abstract = {{We propose a network characterization of combinatorial fitness landscapes by adapting the notion of inherent networks proposed for energy surfaces (Doye, 2002). We use the well-known family of $NK$ landscapes as an example. In our case the inherent network is the graph where the vertices are all the local maxima and edges mean basin adjacency between two maxima. We exhaustively extract such networks on representative small NK landscape instances, and show that they are 'small-worlds'. However, the maxima graphs are not random, since their clustering coefficients are much larger than those of corresponding random graphs. Furthermore, the degree distributions are close to exponential instead of Poissonian. We also describe the nature of the basins of attraction and their relationship with the local maxima network.}},
    keywords = {complex networks ; landscape analysis ; local optima ; network analysis ; nk landscapes},
    language = {Anglais},
    affiliation = {School of Computer Science , Institut des syst{\`e}mes d'information - ISI , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI},
    booktitle = {{Proceedings of the 10th annual conference on Genetic and evolutionary computation}},
    publisher = {ACM New York, NY, USA},
    pages = {555--562},
    address = {Atlanta, {\'E}tats-Unis},
    note = {best paper nomination },
    audience = {internationale },
    collaboration = {university of Lausannes ; university of Nothingham },
    doi = {10.1145/1389095.1389204 },
    year = {2008},
    month = Jul,
    pdf = {http://hal.archives-ouvertes.fr/hal-00331868/PDF/t07pap218-ochoa.pdf},
}

%% hal-00331869, version 1
%% http://hal.archives-ouvertes.fr/hal-00331869
@inproceedings{baccino:hal-00331869,
    hal_id = {hal-00331869},
    url = {http://hal.archives-ouvertes.fr/hal-00331869},
    title = {{Investigating Cognitive Load by Normalized Task-Evoked Pupillary Response}},
    author = {Baccino, Thierry and Kicka, Maud and Dumercy, Laurent and Verel, S{\'e}bastien},
    language = {Anglais},
    affiliation = {Laboratoire de Psychologie Exp{\'e}rimentale et Quantitative - LPEQ , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI},
    booktitle = {{Workshop Cognition and the Web}},
    pages = {45--52},
    address = {France},
    audience = {internationale },
    year = {2008},
    month = Apr,
}

%% hal-00164788, version 1
%% http://hal.archives-ouvertes.fr/hal-00164788
@inproceedings{bercachi:hal-00164788,
    hal_id = {hal-00164788},
    url = {http://hal.archives-ouvertes.fr/hal-00164788},
    title = {{Evolving Dynamic Change and Exchange of Genotype Encoding in Genetic Algorithms for Difficult Optimization Problems}},
    author = {Bercachi, Maroun and Collard, Philippe and Clergue, Manuel and Verel, S{\'e}bastien},
    abstract = {{The application of genetic algorithms (GAs) to many optimization problems in organizations often results in good performance and high quality solutions. For successful and efficient use of GAs, it is not enough to simply apply simple GAs (SGAs). In addition, it is necessary to find a proper representation for the problem and to develop appropriate search operators that fit well to the properties of the genotype encoding. The representation must at least be able to encode all possible solutions of an optimization problem, and genetic operators such as crossover and mutation should be applicable to it. In this paper, serial alternation strategies between two codings are formulated in the framework of dynamic change of genotype encoding in GAs for function optimization. Likewise, a new variant of GAs for difficult optimization problems denoted {\it Split-and-Merge} GA (SM-GA) is developed using a parallel implementation of an SGA and evolving a dynamic exchange of individual representation in the context of Dual Coding concept. Numerical experiments show that the evolved SM-GA significantly outperforms an SGA with static single coding.}},
    keywords = {genetic algorrithm ; representation},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI},
    booktitle = {{Proceedings of the IEEE Congress on Evolutionary Computation CEC2007}},
    publisher = {IEEE Press},
    pages = {4516-4523},
    address = {singapore, Singapour},
    note = {tea team tea team },
    audience = {internationale },
    year = {2007},
    month = Sep,
    pdf = {http://hal.archives-ouvertes.fr/hal-00164788/PDF/maroun-papier-CEC2007.pdf},
}

%% hal-00164789, version 1
%% http://hal.archives-ouvertes.fr/hal-00164789
@inproceedings{simoncini:hal-00164789,
    hal_id = {hal-00164789},
    url = {http://hal.archives-ouvertes.fr/hal-00164789},
    title = {{On the Influence of Selection Operators on Performances in Cellular Genetic Algorithms}},
    author = {Simoncini, David and Collard, Philippe and Verel, S{\'e}bastien and Clergue, Manuel},
    abstract = {{In this paper, we study the influence of the selective pressure on the performance of cellular genetic algorithms. Cellular genetic algorithms are genetic algorithms where the population is embedded on a toroidal grid. This structure makes the propagation of the best so far individual slow down, and allows to keep in the population potentially good solutions. We present two selective pressure reducing strategies in order to slow down even more the best solution propagation. We experiment these strategies on a hard optimization problem, the quadratic assignment problem, and we show that there is a value for of the control parameter for both which gives the best performance. This optimal value does not find explanation on only the selective pressure, measured either by take over time and diversity evolution. This study makes us conclude that we need other tools than the sole selective pressure measures to explain the performances of cellular genetic algorithms.}},
    keywords = {genetic algorithm ; cellular automata ; parallel computation ; diversity},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI},
    booktitle = {{Proceedings of the IEEE Congress on Evolutionary Computation CEC2007}},
    publisher = {IEEE Press},
    pages = {4706-4713},
    address = {singapore, Singapour},
    note = {tea team tea team },
    audience = {internationale },
    year = {2007},
    month = Sep,
    pdf = {http://hal.archives-ouvertes.fr/hal-00164789/PDF/paper1888.pdf},
}

%% hal-00165384, version 1
%% http://hal.archives-ouvertes.fr/hal-00165384
@inproceedings{vanneschi:hal-00165384,
    hal_id = {hal-00165384},
    url = {http://hal.archives-ouvertes.fr/hal-00165384},
    title = {{Fitness landscapes and problem hardness in evolutionary computation}},
    author = {Vanneschi, Leonardo and Verel, S{\'e}bastien},
    keywords = {evolutionary computation ; genetic programming ; genetic algorithm ; fitness landscapes ; neutrality ; performance measure},
    language = {Anglais},
    affiliation = {Dipartimento di Informatica Sistemistica e Comunicazione - DISCo , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI},
    booktitle = {{Proceedings of the 2007 GECCO conference companion on Genetic and evolutionary computation}},
    publisher = {ACM Press},
    pages = {3690-3733},
    address = {London, Royaume-Uni},
    series = {Tutorial },
    note = {tea team tea team },
    audience = {internationale },
    doi = {10.1145/1274000.1274130 },
    year = {2007},
    month = Jul,
}

%% hal-00164926, version 1
%% http://hal.archives-ouvertes.fr/hal-00164926
@inproceedings{vanneschi:hal-00164926,
    hal_id = {hal-00164926},
    url = {http://hal.archives-ouvertes.fr/hal-00164926},
    title = {{A Comprehensive View of Fitness Landscapes with Neutrality and Fitness Clouds}},
    author = {Vanneschi, Leonardo and Collard, Philippe and Verel, S{\'e}bastien and Tomassini, Marco and Pirola, Yuri and Mauri, Giancarlo},
    abstract = {{We define a set of measures that capture some different aspects of neutrality in evolutionary algorithms fitness landscapes from a qualitative point of view. If considered all together, these measures offer a rather complete picture of the characteristics of fitness landscapes bound to neutrality and may be used as broad indicators of problem hardness. We compare the results returned by these measures with the ones of negative slope coefficient, a quantitative measure of problem hardness that has been recently defined and with success rate statistics on a well known genetic programming benchmark: the multiplexer problem. In order to efficaciously study the search space, we use a sampling technique that has recently been introduced and we show its suitability on this problem.}},
    keywords = {evolutionary computation ; automatic programming ; fitness landscape ; neutrality ; performance measure},
    language = {Anglais},
    affiliation = {Dipartimento di Informatica Sistemistica e Comunicazione - DISCo , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , Institut des syst{\`e}mes d'information - ISI},
    booktitle = {{Poster in Genetic Programming}},
    publisher = {Springer},
    pages = {241--250},
    address = {Valencia, Espagne},
    volume = {4445},
    editor = {Marc Ebner and Michael O'Neill and Aniko Ekart and Leonardo Vanneschi and Anna Isabel Esparcia-Alcazar },
    note = {tea team tea team },
    audience = {internationale },
    doi = {10.1007/978-3-540-71605-1\_22 },
    year = {2007},
    month = Apr,
}

%% hal-00164762, version 1
%% http://hal.archives-ouvertes.fr/hal-00164762
@inproceedings{defoinplatel:hal-00164762,
    hal_id = {hal-00164762},
    url = {http://hal.archives-ouvertes.fr/hal-00164762},
    title = {{Density estimation with Genetic Programming for Inverse Problem solving}},
    author = {Defoin Platel, Michael and Verel, S{\'e}bastien and Clergue, Manuel and Chami, Malik},
    abstract = {{This paper addresses the resolution, by Genetic Programming (GP) methods, of ambiguous inverse problems, where for a single input, many outputs can be expected. We propose two approaches to tackle this kind of many-to-one inversion problems, each of them based on the estimation, by a team of predictors, of a probability density of the expected outputs. In the first one, Stochastic Realisation GP, the predictors outputs are considered as the realisations of an unknown random variable which distribution should approach the expected one. The second one, Mixture Density GP, directly models the expected distribution by the mean of a Gaussian mixture model, for which genetic programming has to find the parameters. Encouraging results are obtained on four test problems of different difficulty, exhibiting the interests of such methods.}},
    keywords = {genetic algorithms ; genetic programming ; density estimation ; inverse problem},
    language = {Anglais},
    affiliation = {Laboratoire d'oc{\'e}anographie de Villefranche - LOV , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI},
    booktitle = {{Proceedings of the 10th European Conference on Genetic Programming}},
    publisher = {Springer},
    pages = {45--54},
    address = {Valencia, Espagne},
    volume = {4445},
    editor = {Marc Ebner and Michael O'Neill and Aniko Ekart and Leonardo Vanneschi and Anna Isabel Esparcia-Alcazar },
    series = {Lecture Notes in Computer Science },
    note = {tea team tea team },
    audience = {internationale },
    doi = {10.1007/978-3-540-71605-1\_5 },
    year = {2007},
    month = Apr,
}

%% hal-00164669, version 1
%% http://hal.archives-ouvertes.fr/hal-00164669
@inproceedings{simoncini:hal-00164669,
    hal_id = {hal-00164669},
    url = {http://hal.archives-ouvertes.fr/hal-00164669},
    title = {{From Cells to Islands: An unified Model of Cellular Parallel Genetic Algorithms}},
    author = {Simoncini, David and Collard, Philippe and Verel, S{\'e}bastien and Clergue, Manuel},
    abstract = {{This paper presents the Anisotropic selection scheme for cellular Genetic Algorithms (cGA). This new scheme allows to enhance diversity and to control the selective pressure which are two important issues in Genetic Algorithms, especially when trying to solve difficult optimization problems. Varying the anisotropic degree of selection allows swapping from a cellular to an island model of parallel genetic algorithm. Measures of performances and diversity have been performed on one well-known problem: the Quadratic Assignment Problem which is known to be difficult to optimize. Experiences show that, tuning the anisotropic degree, we can find the accurate trade-off between cGA and island models to optimize performances of parallel evolutionary algorithms. This trade-off can be interpreted as the suitable degree of migration among subpopulations in a parallel Genetic Algorithm.}},
    keywords = {genetic algorithm ; cellular automata ; island model ; complex system ; diversity ; selective pressure ; quadratic assignment problem},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis - I3S},
    booktitle = {{ACRI 2006, 7th International Conference}},
    publisher = {Springer},
    pages = {248-257},
    address = {Perpignan, France},
    volume = {4173},
    editor = {Samira El Yacoubi and Bastien Chopard and Stefania Bandini },
    series = {Lecture Notes in Computer Science },
    note = {tea team tea team },
    audience = {internationale },
    year = {2006},
    month = Sep,
    pdf = {http://hal.archives-ouvertes.fr/hal-00164669/PDF/SimonciniD.pdf},
}

%% hal-00164673, version 1
%% http://hal.archives-ouvertes.fr/hal-00164673
@inproceedings{verel:hal-00164673,
    hal_id = {hal-00164673},
    url = {http://hal.archives-ouvertes.fr/hal-00164673},
    title = {{Neutral Fitness Landscape in the Cellular Automata Majority Problem}},
    author = {Verel, S{\'e}bastien and Collard, Philippe and Tomassini, Marco and Vanneschi, Leonardo},
    abstract = {{We study in detail the fitness landscape of a difficult cellular automata computational task: the majority problem. Our results show why this problem landscape is so hard to search, and we quantify the large degree of neutrality found in various ways. We show that a particular subspace of the solution space, called the "Olympus", is where good solutions concentrate, and give measures to quantitatively characterize this subspace.}},
    keywords = {fitness lanscapes ; evolutionary computation ; genetic algorithm ; neutrality ; cellular automata ; complex system ; majority problem ; density task problem},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis - I3S , Institut des syst{\`e}mes d'information - ISI},
    booktitle = {{ACRI 2006}},
    publisher = {Springer},
    pages = {258-267},
    address = {France},
    volume = {4173},
    editor = {Samira El Yacoubi and Bastien Chopard and Stefania Bandini },
    series = {Lecture Notes in Computer Science },
    note = {tea team tea team },
    audience = {internationale },
    year = {2006},
    month = Sep,
    pdf = {http://hal.archives-ouvertes.fr/hal-00164673/PDF/neutral-fitness-land-CA-majProb.pdf},
}

%% hal-00164694, version 1
%% http://hal.archives-ouvertes.fr/hal-00164694
@inproceedings{beaudoin:hal-00164694,
    hal_id = {hal-00164694},
    url = {http://hal.archives-ouvertes.fr/hal-00164694},
    title = {{Deceptiveness and Neutrality - the ND family of fitness landscapes}},
    author = {Beaudoin, William and Verel, S{\'e}bastien and Collard, Philippe and Escazut, Cathy},
    abstract = {{When a considerable number of mutations have no effects on fitness values, the fitness landscape is said neutral. In order to study the interplay between neutrality, which exists in many real-world applications, and performances of metaheuristics, it is useful to design landscapes which make it possible to tune precisely neutral degree distribution. Even though many neutral landscape models have already been designed, none of them are general enough to create landscapes with specific neutral degree distributions. We propose three steps to design such landscapes: first using an algorithm we construct a landscape whose distribution roughly fits the target one, then we use a simulated annealing heuristic to bring closer the two distributions and finally we affect fitness values to each neutral network. Then using this new family of fitness landscapes we are able to highlight the interplay between deceptiveness and neutrality.}},
    keywords = {evolutionary computation ; genetic algorithm ; fitness landscapes ; neutrality ; performance measure ; fitness distance correlation},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis - I3S},
    booktitle = {{Proceedings of the 8th annual conference on Genetic and evolutionary computation}},
    publisher = {ACM Press},
    pages = {507 - 514},
    address = {Seatle, {\'E}tats-Unis},
    editor = {M. Keijzer et al. },
    note = {tea team tea team },
    audience = {internationale },
    doi = {10.1145/1143997.1144091 },
    year = {2006},
    month = Jul,
    pdf = {http://hal.archives-ouvertes.fr/hal-00164694/PDF/ndfl.pdf},
}

%% hal-00164691, version 1
%% http://hal.archives-ouvertes.fr/hal-00164691
@inproceedings{collard:hal-00164691,
    hal_id = {hal-00164691},
    url = {http://hal.archives-ouvertes.fr/hal-00164691},
    title = {{A Quantitative Study of Neutrality in GP Boolean Landscapes}},
    author = {Collard, Philippe and Mauri, Giancarlo and Pirola, Yuri and Tomassini, Marco and Vanneschi, Leonardo and Verel, S{\'e}bastien},
    abstract = {{Neutrality of some boolean parity fitness landscapes is investigated in this paper. Compared with some well known contributions on the same issue, we define some new measures that help characterizing neutral landscapes, we use a new sampling methodology, which captures some features that are disregarded by uniform random sampling, and we introduce new genetic operators to define the neighborhood of tree structures. We compare the fitness landscape induced by two different sets of functional operators (SNand and SXorNot). The different characteristics of the neutral networks seem to justify the different difficulties of these landscapes for genetic programming.}},
    keywords = {evolutionary computation ; automatic programming ; fitness landscapes ; neutrality ; performance measure},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis - I3S , Dipartimento di Informatica Sistemistica e Comunicazione - DISCo , Institut des syst{\`e}mes d'information - ISI},
    booktitle = {{Proceedings of the 8th annual conference on Genetic and evolutionary computation}},
    publisher = {ACM Press},
    pages = {895 - 902},
    address = {Seatle, {\'E}tats-Unis},
    editor = {M. Keijzer et al. },
    note = {tea team tea team },
    audience = {internationale },
    doi = {10.1145/1143997.1144152 },
    year = {2006},
    month = Jul,
}

%% hal-00164697, version 1
%% http://hal.archives-ouvertes.fr/hal-00164697
@inproceedings{simoncini:hal-00164697,
    hal_id = {hal-00164697},
    url = {http://hal.archives-ouvertes.fr/hal-00164697},
    title = {{Anisotropic selection in cellular genetic algorithms}},
    author = {Simoncini, David and Verel, S{\'e}bastien and Collard, Philippe and Clergue, Manuel},
    abstract = {{In this paper we introduce a new selection scheme in cellular genetic algorithms (cGAs). Anisotropic Selection (AS) promotes diversity and allows accurate control of the selective pressure. First we compare this new scheme with the classical rectangular grid shapes solution according to the selective pressure: we can obtain the same takeover time with the two techniques although the spreading of the best individual is different. We then give experimental results that show to what extent AS promotes the emergence of niches that support low coupling and high cohesion. Finally, using a cGA with anisotropic selection on a Quadratic Assignment Problem we show the existence of an anisotropic optimal value for which the best average performance is observed. Further work will focus on the selective pressure self-adjustment ability provided by this new selection scheme.}},
    keywords = {evolutionary computation ; genetic algorithm ; cellular automata ; parallel model ; selective pressure},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis - I3S},
    booktitle = {{Proceedings of the 8th annual conference on Genetic and evolutionary computation}},
    publisher = {ACM Press},
    pages = {559 - 566},
    address = {Seatle, {\'E}tats-Unis},
    editor = {M. Keijzer et al. },
    note = {tea team tea team },
    audience = {internationale },
    doi = {10.1145/1143997.1144098 },
    year = {2006},
    month = Jul,
    pdf = {http://hal.archives-ouvertes.fr/hal-00164697/PDF/fp063-Simoncini.pdf},
}

%% hal-00164917, version 1
%% http://hal.archives-ouvertes.fr/hal-00164917
@inproceedings{verel:hal-00164917,
    hal_id = {hal-00164917},
    url = {http://hal.archives-ouvertes.fr/hal-00164917},
    title = {{Measuring the Evolvability Landscape to study Neutrality}},
    author = {Verel, S{\'e}bastien and Collard, Philippe and Clergue, Manuel},
    abstract = {{This theoretical work defines the measure of autocorrelation of evolvability in the context of neutral fitness landscape. This measure has been studied on the classical MAX-SAT problem. This work highlight a new characteristic of neutral fitness landscapes which allows to design new adapted metaheuristic.}},
    keywords = {evolutionary computation ; genetic algorithm ; fitness landscape ; neutrality ; evolvability},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis - I3S},
    booktitle = {{Poster at Genetic and Evolutionary Computation -- GECCO-2006}},
    publisher = {ACM Press},
    pages = {613--614},
    address = {Seattle, WA, {\'E}tats-Unis},
    editor = {M. Keijzer and et al. },
    note = {tea team tea team },
    audience = {internationale },
    year = {2006},
    month = Jul,
    pdf = {http://hal.archives-ouvertes.fr/hal-00164917/PDF/pp037-verel.pdf},
}

%% hal-00164684, version 1
%% http://hal.archives-ouvertes.fr/hal-00164684
@inproceedings{vanneschi:hal-00164684,
    hal_id = {hal-00164684},
    url = {http://hal.archives-ouvertes.fr/hal-00164684},
    title = {{Negative slope coefficient. a measure to characterize genetic programming fitness landscapes}},
    author = {Vanneschi, Leonardo and Tomassini, Marco and Collard, Philippe and Verel, S{\'e}bastien},
    abstract = {{Negative slope coefficient has been recently introduced and empirically proven a suitable hardness indicator for some well known genetic programming benchmarks, such as the even parity problem, the binomial-3 and the artificial ant on the Santa Fe trail. Nevertheless, the original definition of this measure contains several limitations. This paper points out some of those limitations, presents a new and more relevant definition of the negative slope coefficient and empirically shows the suitability of this new definition as a hardness measure for some genetic programming benchmarks, including the multiplexer, the intertwined spirals problem and the royal trees}},
    keywords = {evolutionary computation ; genetic programming ; fitness landscapes ; neutrality ; fitness cloud ; fitness correlation ; problem hardness},
    language = {Anglais},
    affiliation = {Institut des syst{\`e}mes d'information - ISI , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis - I3S},
    booktitle = {{EUROGP'06, Genetic Programming, 9th European Conference}},
    publisher = {Springer},
    pages = {178-189},
    address = {France},
    volume = {3905},
    editor = {Pierre Collet and Marco Tomassini and Marc Ebner and Steven Gustafson and Aniko Ekart },
    series = {Lecture Notes in Computer Science },
    note = {tea team tea team },
    audience = {internationale },
    doi = {10.1007/11729976\_16 },
    year = {2006},
    month = Apr,
    pdf = {http://hal.archives-ouvertes.fr/hal-00164684/PDF/fulltext.pdf},
}

%% hal-00164910, version 1
%% http://hal.archives-ouvertes.fr/hal-00164910
@inproceedings{collard:hal-00164910,
    hal_id = {hal-00164910},
    url = {http://hal.archives-ouvertes.fr/hal-00164910},
    title = {{Local search heuristics: Fitness Cloud versus Fitness Landscape}},
    author = {Collard, Philippe and Verel, S{\'e}bastien and Clergue, Manuel},
    abstract = {{This paper introduces the concept of fitness cloud as an alternative way to visualize and analyze search spaces than given by the geographic notion of fitness landscape. It is argued that the fitness cloud concept overcomes several deficiencies of the landscape representation. Our analysis is based on the correlation between fitness of solutions and fitnesses of nearest solutions according to some neighboring. We focus on the behavior of local search heuristics, such as hill climber, on the well-known NK fitness landscape. In both cases the fitness vs. fitness correlation is shown to be related to the epistatic parameter K.}},
    keywords = {evolutionary computation ; genetic algorithm ; local search ; fitness correlation ; fitness landscape ; neutrality ; evolvability},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis - I3S},
    booktitle = {{Poster at the 2004 European Conference on Artificial Intelligence (ECAI04)}},
    publisher = {IOS Press},
    pages = {973 - 974},
    address = {Valencia, Espagne},
    editor = {R. L. de Mantaras and L. Saitta },
    note = {tea team tea team },
    audience = {internationale },
    year = {2004},
    month = Aug,
    pdf = {http://hal.archives-ouvertes.fr/hal-00164910/PDF/poster\_ecai04.pdf},
}

%% hal-00160051, version 1
%% http://hal.archives-ouvertes.fr/hal-00160051
@inproceedings{collard:hal-00160051,
    hal_id = {hal-00160051},
    url = {http://hal.archives-ouvertes.fr/hal-00160051},
    title = {{How to use the Scuba Diving metaphor to solve problem with neutrality ?}},
    author = {Collard, Philippe and Verel, S{\'e}bastien and Clergue, Manuel},
    abstract = {{We proposed a new search heuristic using the scuba diving metaphor. This approach is based on the concept of evolvability and tends to exploit neutrality which exists in many real-world problems. Despite the fact that natural evolution does not directly select for evolvability, the basic idea behind the scuba search heuristic is to explicitly push evolvability to increase. A comparative study of the scuba algorithm and standard local search heuristics has shown the advantage and the limitation of the scuba search. In order to tune neutrality, we use the NKq fitness landscapes and a family of travelling salesman problems (TSP) where cities are randomly placed on a lattice and where travel distance between cities is computed with the Manhattan metric. In this last problem the amount of neutrality varies with the city concentration on the grid ; assuming the concentration below one, this TSP reasonably remains a NP-hard problem.}},
    keywords = {local search ; fitness landscapes ; neutrality ; evolvability ; Travelling salesman problem},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis - I3S},
    booktitle = {{ECAI'2004}},
    publisher = {IOS Press},
    pages = {166-170},
    address = {Valencia, Espagne},
    editor = {R. L. de Mantaras ; L. Saitta },
    audience = {non sp{\'e}cifi{\'e}e },
    year = {2004},
    month = Aug,
    pdf = {http://hal.archives-ouvertes.fr/hal-00160051/PDF/ecai04\_Final.pdf},
}

%% hal-00160055, version 1
%% http://hal.archives-ouvertes.fr/hal-00160055
@inproceedings{vanneschi:hal-00160055,
    hal_id = {hal-00160055},
    url = {http://hal.archives-ouvertes.fr/hal-00160055},
    title = {{Fitness Clouds and Problem Hardness in Genetic Programming}},
    author = {Vanneschi, Leonardo and Clergue, Manuel and Collard, Philippe and Tomassini, Marco and Verel, S{\'e}bastien},
    abstract = {{This paper presents an investigation of genetic programming fitness landscapes. We propose a new indicator of problem hardness for tree-based genetic programming, called negative slope coefficient, based on the concept of fitness cloud. The negative slope coefficient is a predictive measure, i.e. it can be calculated without prior knowledge of the global optima.The fitness cloud is generated via a sampling of individuals obtained with the Metropolis-Hastings method. The reliability of the negative slope coefficient is tested on a set of well known and representative genetic programming benchmarks, comprising the binomial-3 problem, the even parity problem and the artificial ant on the Santa Fe trail.}},
    keywords = {fitness landscape ; genetic programming ; evolutionary computation ; fitness cloud ; problem hardness},
    language = {Anglais},
    affiliation = {Institut des syst{\`e}mes d'information - ISI , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis - I3S},
    booktitle = {{Genetic and Evolutionary Computation 2004}},
    publisher = {Springer-Verlag},
    pages = {690--701},
    address = {Seattle, WA, {\'E}tats-Unis},
    editor = {Kalyanmoy Deb ; Riccardo Poli ; Wolfgang Banzhaf ; Hans-Georg Beyer ; Edmund Burke },
    audience = {internationale },
    collaboration = {Information Systems Department ; laboratoire I3S },
    doi = {10.1007/b98645 },
    year = {2004},
    month = Jun,
    pdf = {http://hal.archives-ouvertes.fr/hal-00160055/PDF/fc\_gp.pdf},
}

%% hal-00160035, version 1
%% http://hal.archives-ouvertes.fr/hal-00160035
@inproceedings{verel:hal-00160035,
    hal_id = {hal-00160035},
    url = {http://hal.archives-ouvertes.fr/hal-00160035},
    title = {{Scuba Search : when selection meets innovation}},
    author = {Verel, S{\'e}bastien and Collard, Philippe and Clergue, Manuel},
    abstract = {{We proposed a new search heuristic using the scuba diving metaphor. This approach is based on the concept of evolvability and tends to exploit neutrality in fitness landscape. Despite the fact that natural evolution does not directly select for evolvability, the basic idea behind the scuba search heuristic is to explicitly push the evolvability to increase. The search process switches between two phases: Conquest-of-the-Waters and Invasion-of-the-Land. A comparative study of the new algorithm and standard local search heuristics on the NKq-landscapes has shown advantage and limit of the scuba search. To enlighten qualitative differences between neutral search processes, the space is changed into a connected graph to visualize the pathways that the search is likely to follow.}},
    keywords = {Local search ; Search algorithm ; Heuristic method ; Fitness Landscape ; Neutrality ; Evolvability ; Evolutionary algorithm ;},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis - I3S},
    booktitle = {{Evolutionary Computation, 2004. CEC2004}},
    publisher = {IEEE Press},
    pages = {924 - 931},
    address = {Portland (Oregon), {\'E}tats-Unis},
    audience = {non sp{\'e}cifi{\'e}e },
    doi = {10.1109/CEC.2004.1330960 },
    year = {2004},
    month = Jun,
    pdf = {http://hal.archives-ouvertes.fr/hal-00160035/PDF/cec2004\_Final.pdf},
}

%% hal-00159994, version 1
%% http://hal.archives-ouvertes.fr/hal-00159994
@inproceedings{verel:hal-00159994,
    hal_id = {hal-00159994},
    url = {http://hal.archives-ouvertes.fr/hal-00159994},
    title = {{Where are Bottlenecks in NK Fitness Landscapes?}},
    author = {Verel, S{\'e}bastien and Collard, Philippe and Clergue, Manuel},
    abstract = {{Usually the offspring-parent fitness correlation is used to visualize and analyze some caracteristics of fitness landscapes such as evolvability. In this paper, we introduce a more general representation of this correlation, the Fitness Cloud (FC). We use the bottleneck metaphor to emphasise fitness levels in landscape that cause local search process to slow down. For a local search heuristic such as hill-climbing or simulated annealing, FC allows to visualize bottleneck and neutrality of landscapes. To confirm the relevance of the FC representation we show where the bottlenecks are in the well-know NK fitness landscape and also how to use neutrality information from the FC to combine some neutral operator with local search heuristic.}},
    keywords = {fitness landscape ; fitness cloud ; NK-landscapes ; local search ; evolvability ; neutrality},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis - I3S},
    booktitle = {{Evolutionary Computation, 2003. CEC'03}},
    publisher = {IEEE Press},
    pages = {273--280},
    address = {Canberra, Australie},
    editor = {Ruhul Sarker ; Robert Reynolds ; Hussein Abbass ; Kay Chen Tan ; Bob McKay ; Daryl Essam ; Tom Gedeon },
    audience = {non sp{\'e}cifi{\'e}e },
    doi = {10.1109/CEC.2003.1299585 },
    year = {2003},
    month = Dec,
    pdf = {http://hal.archives-ouvertes.fr/hal-00159994/PDF/cec2003\_final.pdf},
}

%% hal-00159730, version 1
%% http://hal.archives-ouvertes.fr/hal-00159730
@inproceedings{defoinplatel:hal-00159730,
    hal_id = {hal-00159730},
    url = {http://hal.archives-ouvertes.fr/hal-00159730},
    title = {{From Royal Road to Epistatic Road for Variable Length Evolution Algorithm}},
    author = {Defoin Platel, Michael and Verel, Sebastien and Clergue, Manuel and Collard, Philippe},
    abstract = {{Although there are some real world applications where the use of variable length representation (VLR) in Evolutionary Algorithm is natural and suitable, an academic framework is lacking for such representations. In this work we propose a family of tunable fitness landscapes based on VLR of genotypes. The fitness landscapes we propose possess a tunable degree of both neutrality and epistasis; they are inspired, on the one hand by the Royal Road fitness landscapes, and the other hand by the NK fitness landscapes. So these landscapes offer a scale of continuity from Royal Road functions, with neutrality and no epistasis, to landscapes with a large amount of epistasis and no redundancy. To gain insight into these fitness landscapes, we first use standard tools such as adaptive walks and correlation length. Second, we evaluate the performances of evolutionary algorithms on these landscapes for various values of the neutral and the epistatic parameters; the results allow us to correlate the performances with the expected degrees of neutrality and epistasis.}},
    keywords = {evolutionary computation ; variable length representation ; benchmarck ; fitness landscape ; neutrality},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis - I3S},
    booktitle = {{Lecture notes in computer science (Lect. notes comput. sci.) ISSN 0302-9743}},
    publisher = {Springer, Berlin, ALLEMAGNE},
    pages = {3-14},
    address = {Marseille, France},
    editor = {Liardet Pierre ; Collet Pierre ; Fonlupt Cyril ; Lutton Evelyne ; Schoenauer Marc },
    audience = {internationale },
    year = {2003},
    month = Oct,
    pdf = {http://hal.archives-ouvertes.fr/hal-00159730/PDF/FinalActes\_45.pdf},
}

%% hal-00518206, version 1
%% http://hal.archives-ouvertes.fr/hal-00518206
@inproceedings{verel:hal-00518206,
    hal_id = {hal-00518206},
    url = {http://hal.archives-ouvertes.fr/hal-00518206},
    title = {{States based evolutionary algorithm}},
    author = {Verel, S{\'e}bastien and Collard, Philippe and Clergue, Manuel},
    abstract = {{Choosing the suitable representation, the operators and the values of the parameters of an evolutionary algorithm is one of the main problems to design an efficient algorithm for one particular optimization problem. This additional information to the evolutionary algorithm generally is called the algorithm parameter, or parameter. This work introduces a new evolutionary algorithm, States based Evolutionary Algorithm which is able to combine different evolutionary algorithms with different parameters included different representations in order to control the parameters and to take the advantage of each possible evolution algorithm during the optimization process. This paper gives first experimental arguments of the efficiency of the States based EA.}},
    keywords = {evolutionary algorithms ; parameters settings ; parameters control ; parallel evolutionary algorithms},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , DOLPHIN - INRIA Lille - Nord Europe},
    booktitle = {{Workshop selfstar at conference PPSN}},
    address = {Krakow, Pologne},
    collaboration = {scobi team },
    year = {2010},
    month = Sep,
    pdf = {http://hal.archives-ouvertes.fr/hal-00518206/PDF/statesEA-ppsn.pdf},
}

%% hal-00460436, version 1
%% http://hal.archives-ouvertes.fr/hal-00460436
@inproceedings{ochoa:hal-00460436,
    hal_id = {hal-00460436},
    url = {http://hal.archives-ouvertes.fr/hal-00460436},
    title = {{Local Optima Networks: Current Results and Perspectives}},
    author = {Ochoa, Gabriela and Verel, S{\'e}bastien and Tomassini, Marco and Daolio, Fabio},
    abstract = {{[1] G. Ochoa, M. Tomassini, S. Verel, and C. Darabos, "A study of NK landscapes' basins and local optima networks," in Genetic and Evolutionary Computation Conference, GECCO 2008. ACM, 2008, pp. 555-562. [2] S. Verel, G. Ochoa, and M. Tomassini, "The connectivity of NK landscapes' basins: a network analysis," in Artificial Life XI: Proceedings of the Eleventh International Conference on the Simulation and Synthesis of Living Systems, S. Bullock, J. Noble, R. Watson, and M. A. Bedau, Eds. MIT Press, Cambridge, MA, 2008, pp. 648-655. [3] M. Tomassini, S. Verel, and G. Ochoa, "Complex-network analysis of combinatorial spaces: The NK landscape case," Phys. Rev. E, vol. 78, no. 6, p. 066114, 2008. [4] J. P. K. Doye, "The network topology of a potential energy landscape: a static scale-free network," Phys. Rev. Lett., vol. 88, p. 238701, 2002. [5] S. Verel, G. Ochoa, and M. Tomassini, "Local Optima Networks of NK Landscapes with Neutrality", (to be publish) [6] F. Dolio, S. Verel, G. Ochoa, M.Tomassini ,"Local Optima Networks of the Quadratic Assignment Problem", in IEEE Congress on Evolutionary Computation, 2010 (submitted)}},
    keywords = {fitness landscapes ; local optima ; networks ; local search ; evolutionary computation},
    language = {Anglais},
    affiliation = {School of Computer Science , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , DOLPHIN - INRIA Lille - Nord Europe , Institut des syst{\`e}mes d'information - ISI},
    booktitle = {{4th Workshop on Theory of Randomized Search Heuristics}},
    address = {Paris, France},
    year = {2010},
    month = Mar,
}

%% hal-00460442, version 1
%% http://hal.archives-ouvertes.fr/hal-00460442
@inproceedings{verel:hal-00460442,
    hal_id = {hal-00460442},
    url = {http://hal.archives-ouvertes.fr/hal-00460442},
    title = {{Set-based Multiobjective Fitness Landscapes: definition, properties.}},
    author = {Verel, S{\'e}bastien and Jourdan, Laetitia and Dhaenens, Clarisse and Liefooghe, Arnaud},
    abstract = {{One of the most commonly-used metaphors to describe the process of heuristic search methods in solving combinatorial optimization problems is the Fitness Landscape (FiL). This landscape metaphor appears most commonly in works related to single-objective optimization: the search space can then be regarded as a spatial structure where each point (solution) has some neighbor's points, determined according to a neighborhood operator, and has a height (its objective function value), both forming a landscape surface. However, no definition of FiL establishes an equivalence in the context of multiobjective optimization. As a first step, we examine a possible definition where the points represents feasible solutions in the decision space and the "height" represents their vector fitness function.In such a case, the standard definitions of local optimum turns into the definition of Pareto local optimum, and the global optimum one to the Pareto optimal set. In this context, it is still possible to define the ruggedness of a given landscape. The analysis of such concepts for a given problem is relevant to obtain deep information about its optimization difficulty. But unfortunately, they fail to explain the dynamics of some local search heuristics. Another possible definition of a multiobjective Fitness Landscape (moFiL) may map each point to a set of feasible solutions.A neighbor is then defined by either i) inserting a solution into the set, ii) deleting iii) or mutating one solution of the set. The height can be given in terms of an arbitrary quality indicator, like the hypervolume. This definition follows recent works dealing with set-based search heuristics. We will examine and discuss the challenging questions of this definition of moFiL.}},
    keywords = {fitness landscapes ; local optima ; networks ; local search ; evolutionary computation},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , DOLPHIN - INRIA Lille - Nord Europe , Laboratoire d'Informatique Fondamentale de Lille - LIFL},
    booktitle = {{4th Workshop on Theory of Randomized Search Heuristics}},
    address = {Paris, France},
    year = {2010},
    month = Mar,
}

%% hal-00425367, version 1
%% http://hal.archives-ouvertes.fr/hal-00425367
@inproceedings{ochoa:hal-00425367,
    hal_id = {hal-00425367},
    url = {http://hal.archives-ouvertes.fr/hal-00425367},
    title = {{Local Optima Networks of NK Landscapes with and without Neutrality}},
    author = {Ochoa, Gabriela and Verel, S{\'e}bastien and Tomassini, Marco},
    abstract = {{We propose a network characterization of combinatorial fitness landscapes by adapting the notion of inherent networks proposed for energy surfaces. We use the well-known family of NK landscapes as an example. In our case the inherent network is the graph whose vertices represent the local maxima in the landscape, and the edges account for the transition probabilities between their corresponding basins of attraction. We exhaustively extracted such networks on representative NK landscape instances, and performed a statistical characterization of their properties. We found that most of these network properties are related to the search difficulty on the underlying NK landscapes with varying values of K. In further work, we extended this formalism to neutral fitness landscapes, which are extremely common in difficult combinatorial search spaces. By using two known neutral variants of the NK family (i.e.NK\_p and NK\_q) in which the amount of neutrality can be tuned by a parameter, we show that our new definitions of the optima networks and the associated basins are coherent with the previous definitions for the non-neutral case. Moreover, our empirical study and statistical analysis show that the features of neutral landscapes interpolate smoothly between landscapes with maximum neutrality and non-neutral ones. We found some unknown structural differences between the two studied families of neutral landscapes. But overall, the network features studied confirmed that neutrality in a landscape may enhance heuristic search. The methodologies introduced here should be useful in the future to design new search heuristics or modifications to existing ones such that the configuration space can be searched more effectively.}},
    keywords = {fitness landscapes ; local optima ; networks ; local search ; evolutionary computation},
    language = {Anglais},
    affiliation = {School of Computer Science , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI , Institut des syst{\`e}mes d'information - ISI},
    booktitle = {{3rd Workshop on Theory of Randomized Search Heuristics}},
    address = {Birmingham, Royaume-Uni},
    year = {2009},
    month = Oct,
}

%% hal-00433254, version 1
%% http://hal.archives-ouvertes.fr/hal-00433254
@inproceedings{tomassini:hal-00433254,
    hal_id = {hal-00433254},
    url = {http://hal.archives-ouvertes.fr/hal-00433254},
    title = {{The network structure of hard combinatorial landscapes.}},
    author = {Tomassini, Marco and Ochoa, Gabriela and Verel, S{\'e}bastien},
    keywords = {fitness landscapes ; local optima ; networks ; local search ; evolutionary computation},
    language = {Anglais},
    affiliation = {Institut des syst{\`e}mes d'information - ISI , School of Computer Science , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI},
    booktitle = {{BCNetWORKSHOP trends and perspectives in complex networks}},
    address = {Barcelona, Espagne},
    year = {2008},
    month = Dec,
}

%% hal-00164913, version 1
%% http://hal.archives-ouvertes.fr/hal-00164913
@inproceedings{simoncini:hal-00164913,
    hal_id = {hal-00164913},
    url = {http://hal.archives-ouvertes.fr/hal-00164913},
    title = {{A preliminary investigation of anisotropic selection in celullar genetic algorithms}},
    author = {Simoncini, David and Verel, S{\'e}bastien and Collard, Philippe and Clergue, Manuel},
    keywords = {evolutionary computation ; cellular automata ; cellular genetic algorithm ; selective pressure},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis - I3S},
    booktitle = {{Poster at Evolution Artificielle, 7th International Conference}},
    address = {Lillle, France},
    note = {tea team tea team },
    year = {2005},
    month = Oct,
}

%% hal-00331863, version 1
%% http://hal.archives-ouvertes.fr/hal-00331863
@incollection{bercachi:hal-00331863,
    hal_id = {hal-00331863},
    url = {http://hal.archives-ouvertes.fr/hal-00331863},
    title = {{Studying the Effects of Dual Coding on the Adaptation of Representation for Linkage in Evolutionary Algorithms}},
    author = {Bercachi, Maroun and Collard, Philippe and Clergue, Manuel and Verel, S{\'e}bastien},
    abstract = {{For successful and efficient use of GAs, it is not enough to simply apply simple GAs (SGAs). In addition, it is necessary to find a proper representation for the problem and to integrate linkage information about the problem structure. Similarly, it is important to develop appropriate search operators that fit well to the properties of the genotype encoding and that can learn linkage information to assisst in creating and not in destroying the building blocks. Besides, the representation must at least be able to encode all possible solutions of an optimization problem, and genetic operators such as crossover and mutation should be applicable to it. In this chapter, sequential alternation strategies between two coding schemes are formulated in the framework of dynamic change of genotype encoding in GAs for function optimization. Likewise, new variants of GAs for difficult optimization problems are developed using a parallel implementation of GAs and evolving a dynamic exchange of individual representation in the context of dual coding concepts. Numerical experiments show that the evolved proposals significantly outperform a SGA with static single coding.}},
    keywords = {Genetic Algorithms ; Difficult Optimization ; Performance ; Dynamic Representation ; Serialization ; Parallelization ; Agents ; Steady State ; Linkage},
    language = {Anglais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI},
    booktitle = {{Linkage in Evolutionary Computation}},
    publisher = {Springer Berlin / Heidelberg},
    pages = {249-284},
    editor = {Chen, Ying-ping and Lim, Meng-Hiot },
    series = {Studies in Computational Intelligence },
    note = {tea team tea team },
    doi = {10.1007/978-3-540-85068-7 },
    year = {2008},
    month = Sep,
}

%% tel-00159727, version 1
%% http://tel.archives-ouvertes.fr/tel-00159727
@phdthesis{verel:tel-00159727,
    hal_id = {tel-00159727},
    url = {http://tel.archives-ouvertes.fr/tel-00159727},
    title = {{Etude et Exploitation des R{\'e}seaux de Neutralit{\'e} dans les Paysages Adaptatifs pour l'Optimisation Difficile}},
    author = {Verel, S{\'e}bastien},
    abstract = {{Le concept de paysage adaptatif a {\'e}t{\'e} introduit par S. Wright dans le domaine de la biologie de l'{\'e}volution dans les ann{\'e}es 1930. Il est l'un des concepts pertinents pour mod{\'e}liser l'{\'e}volution d'une population d'organismes. Dans le domaine de l'optimisation combinatoire par m{\'e}taheuristiques, il est {\'e}galement utilis{\'e} et permet de lier une description g{\'e}om{\'e}trique d'un probl{\`e}me d'optimisation avec la dynamique des algorithmes de recherche.Deux g{\'e}om{\'e}tries de paysage correspondant {\`a} deux dynamiques d'algorithme ont {\'e}t{\'e} principalement {\'e}tudi{\'e}es. La g{\'e}om{\'e}trie de paysage multimodale est li{\'e}e {\`a} la pr{\'e}sence d'optima locaux,o{\`u} la dynamique est une succession de marches adaptatives vers de meilleures solutions et de d{\'e}gradations de performance. La g{\'e}om{\'e}trie des paysages adaptatifs neutres, mise en avant par la th{\'e}orie de la neutralit{\'e} en {\'e}volution mol{\'e}culaire de Motoo Kimura,est li{\'e}e {\`a} la pr{\'e}sence de plateaux ; la dynamique se caract{\'e}rise alors par une d{\'e}rive al{\'e}atoire entrecoup{\'e}e de rares d{\'e}couvertes de solutions plus performantes. Cette th{\`e}se se propose d'approfondir l'{\'e}tude des paysages neutres dans le contexte de l'optimisation et de proposer de nouvelles m{\'e}taheuristiques adapt{\'e}es {\`a} ce type de paysages.La th{\`e}se se compose de quatre chapitres. Dans un premier chapitre,nous pr{\'e}sentons les principaux r{\'e}sultats concernant les paysages adaptatifs et plus particuli{\`e}rement les paysages adaptatifs neutres.Dans un deuxi{\`e}me chapitre, nous d{\'e}veloppons le concept d'ensemble de neutralit{\'e} en introduisant la notion de 'nuage adaptatif' qui permet d'{\'e}tudier la corr{\'e}lation de performance entre solutions voisines et nous l'appliquons {\`a} la classe des paysages 'embarqu{\'e}s' qui regroupe les paysages NK et Max-SAT. Dans un troisi{\`e}me chapitre, nous r{\'e}sumons l'ensemble des mesures relatives aux r{\'e}seaux de neutralit{\'e} et nous proposons une nouvelle mesure. Une {\'e}tude exp{\'e}rimentale est r{\'e}alis{\'e}e sur trois familles de paysages pour lesquelles la neutralit{\'e} est ajustable et deux probl{\`e}mes classiques de la litt{\'e}rature. Enfin, un nouvel algorithme de recherche adapt{\'e} aux paysages neutres li{\'e} {\`a} la nouvelle mesure est propos{\'e} et {\'e}valu{\'e} sur diff{\'e}rents paysages neutres. Nous r{\'e}alisons l'{\'e}tude du paysage adaptatif massivement neutreissu du probl{\`e}me d'apprentissage de la r{\`e}gle d'un automate cellulaire r{\'e}alisant la t{\^a}che de classification par la densit{\'e}, afin d'en am{\'e}liorer les m{\'e}taheuristiques connues existantes.}},
    keywords = {Paysage Adaptatif ; Neutralit{\'e} ; M{\'e}taheuristique ; Optimisation Difficile ; Algorithme {\'E}volutionnaire ; R{\'e}seau de Neutralit{\'e}},
    language = {Fran{\c c}ais},
    affiliation = {Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis - I3S},
    school = {Universit{\'e} de Nice Sophia-Antipolis},
    type = {THESE},
    year = {2005},
    month = Dec,
    pdf = {http://tel.archives-ouvertes.fr/tel-00159727/PDF/memoireSverel.pdf},
}

%% hal-00665421, version 1
%% http://hal.inria.fr/hal-00665421
@techreport{humeau:hal-00665421,
    hal_id = {hal-00665421},
    url = {http://hal.inria.fr/hal-00665421},
    title = {{ParadisEO-MO: From Fitness Landscape Analysis to Efficient Local Search Algorithms}},
    author = {Humeau, J{\'e}r{\'e}mie and Liefooghe, Arnaud and Talbi, El-Ghazali and Verel, S{\'e}bastien},
    abstract = {{This document presents a general-purpose software framework dedicated to the design, the analysis and the implementation of local search algorithms: ParadisEO-MO. A substantial number of single-solution based local search metaheuristics has been proposed so far, and an attempt of unifying existing approaches is here presented. Based on a fine-grained decomposition, a conceptual model is proposed and is validated by regarding a number of state-of-the-art methodologies as simple variants of the same structure. This model is then incorporated into the ParadisEO-MO software framework. This framework has proven its efficiency and high flexibility by enabling the resolution of many academic and real-world optimization problems from science and industry.}},
    language = {Anglais},
    affiliation = {DOLPHIN - INRIA Lille - Nord Europe , UR Informatique Automatique , Laboratoire d'Informatique Fondamentale de Lille - LIFL , Laboratoire d'Informatique, Signaux, et Syst{\`e}mes de Sophia-Antipolis (I3S) / Groupe SCOBI},
    institution = {INRIA},
    number = {RR-7871},
    year = {2012},
    pdf = {http://hal.inria.fr/hal-00665421/PDF/RR-7871.pdf},
}