3,859 research outputs found

    A hybrid genetic algorithm and inver over approach for the travelling salesman problem

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    This article posted here with permission of the IEEE - Copyright @ 2010 IEEEThis paper proposes a two-phase hybrid approach for the travelling salesman problem (TSP). The first phase is based on a sequence based genetic algorithm (SBGA) with an embedded local search scheme. Within the SBGA, a memory is introduced to store good sequences (sub-tours) extracted from previous good solutions and the stored sequences are used to guide the generation of offspring via local search during the evolution of the population. Additionally, we also apply some techniques to adapt the key parameters based on whether the best individual of the population improves or not and maintain the diversity. After SBGA finishes, the hybrid approach enters the second phase, where the inver over (IO) operator, which is a state-of-the-art algorithm for the TSP, is used to further improve the solution quality of the population. Experiments are carried out to investigate the performance of the proposed hybrid approach in comparison with several relevant algorithms on a set of benchmark TSP instances. The experimental results show that the proposed hybrid approach is efficient in finding good quality solutions for the test TSPs.This work was supported by the Engineering and Physical Sciences Research Council (EPSRC) of the United Kingdom under Grant EP/E060722/1

    A sequence based genetic algorithm with local search for the travelling salesman problem

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    The standard Genetic Algorithm often suffers from slow convergence for solving combinatorial optimization problems. In this study, we present a sequence based genetic algorithm (SBGA) for the symmetric travelling salesman problem (TSP). In our proposed method, a set of sequences are extracted from the best individuals, which are used to guide the search of SBGA. Additionally, some procedures are applied to maintain the diversity by breaking the selected sequences into sub tours if the best individual of the population does not improve. SBGA is compared with the inver-over operator, a state-of-the-art algorithm for the TSP, on a set of benchmark TSPs. Experimental results show that the convergence speed of SBGA is very promising and much faster than that of the inver-over algorithm and that SBGA achieves a similar solution quality on all test TSPs

    Foreign bank subsidiariesā€™ risk-taking behavior: Impact of home and host country national culture

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    This paper examines whether the risk-taking behavior of foreign affiliates of multinational banks is more influenced by the national culture of their parent banksā€™ home country or the national culture of foreign affiliatesā€™ host country. The study uses a dataset of 292 foreign affiliates (i.e., subsidiaries or branch operations) operating in 66 countries having parent banks in 26 countries for empirical analysis. National culture of both home and host countries is measured with four dimensionsā€”uncertainty avoidance, individualism, masculinity and power distanceā€”of Hofstede's framework of national culture. Findings suggest that the national culture of parent banksā€™ home country has higher impact on the risk-taking behavior of foreign affiliates of multinational banks than the national culture of their host country. Specifically, foreign affiliatesā€™ risk-taking is higher if parent banksā€™ home country has low uncertainty avoidance, high individualism and low power distance cultural values. This study extends our understanding that how informal institutions, such as the national culture, influence the financial decisions in multinational banks

    Swarming and swirling in self-propelled polar granular rods

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    Using experiments with anisotropic vibrated rods and quasi-2D numerical simulations, we show that shape plays an important role in the collective dynamics of self-propelled (SP) particles. We demonstrate that SP rods exhibit local ordering, aggregation at the side walls, and clustering absent in round SP particles. Furthermore, we find that at sufficiently strong excitation SP rods engage in a persistent swirling motion in which the velocity is strongly correlated with particle orientation.Comment: 4 page
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