| [article] 
					| Titre : | Revisiting the big valley search space structure in the TSP |  
					| Type de document : | texte imprimé |  
					| Auteurs : | Hains, D. R., Auteur ; Whitley, L. D., Auteur ; Howe, A. E., Auteur |  
					| Année de publication : | 2011 |  
					| Article en page(s) : | pp. 305–312 |  
					| Note générale : | Recherche opérationnelle |  
					| Langues : | Anglais (eng) |  
					| Mots-clés : | Combinatorial optimization Local search Travelling salesman problem |  
					| Index. décimale : | 001.424 |  
					| Résumé : | The solution space of the travelling salesman problem under 2-opt moves has been characterized as having a big-valley structure, in which the evaluation of a tour is positively correlated to the distance of the tour from the global optimum. We examine the big-valley hypothesis more closely and show that while the big-valley structure does appear in much of the solution space, it breaks down around local optima that have solutions whose evaluation is very close to that of the global optimum; multiple funnels appear around local optima with evaluations close to the global optimum. The appearance of multiple funnels explains why certain iterated local search heuristics can quickly find high-quality solutions, but fail to consistently find the global optimum. We then investigate a novel search operator, which is demonstrated to have the ability to escape funnels at evaluations close to the global optimum. |  
					| DEWEY : | 001.424 |  
					| ISSN : | 0160-5682 |  
					| En ligne : | http://www.palgrave-journals.com/jors/journal/v62/n2/abs/jors2010116a.html |  in Journal of the operational research society (JORS) > Vol. 62 N° 2 Special issue  (Fevrier 2011) . - pp. 305–312
 [article] Revisiting the big valley search space structure in the TSP [texte imprimé] / Hains, D. R. , Auteur ; Whitley, L. D. , Auteur ; Howe, A. E. , Auteur . - 2011 . - pp. 305–312. Recherche opérationnelleLangues  : Anglais (eng )in Journal of the operational research society (JORS)  > Vol. 62 N° 2 Special issue  (Fevrier 2011)  . - pp. 305–312 
					| Mots-clés : | Combinatorial optimization Local search Travelling salesman problem |  
					| Index. décimale : | 001.424 |  
					| Résumé : | The solution space of the travelling salesman problem under 2-opt moves has been characterized as having a big-valley structure, in which the evaluation of a tour is positively correlated to the distance of the tour from the global optimum. We examine the big-valley hypothesis more closely and show that while the big-valley structure does appear in much of the solution space, it breaks down around local optima that have solutions whose evaluation is very close to that of the global optimum; multiple funnels appear around local optima with evaluations close to the global optimum. The appearance of multiple funnels explains why certain iterated local search heuristics can quickly find high-quality solutions, but fail to consistently find the global optimum. We then investigate a novel search operator, which is demonstrated to have the ability to escape funnels at evaluations close to the global optimum. |  
					| DEWEY : | 001.424 |  
					| ISSN : | 0160-5682 |  
					| En ligne : | http://www.palgrave-journals.com/jors/journal/v62/n2/abs/jors2010116a.html | 
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