The free clustered travelling salesman problem (FCTSP) is an extension of the classical travelling salesman problem where the set of vertices is partitioned into clusters, and the task is to find a minimum cost Hamiltonian tour such that the vertices in any cluster are visited contiguously. This paper proposes the use of a memetic algorithm (MA) that combines the global search ability of Geneti...

Ant Colony optimization has proved suitable to solve a wide range of combinatorial optimization (or NP-hard) problems as the Travelling Salesman Problem (TSP). The first step of ACO algorithm is to set the parameters that drive the algorithm. The parameter has an important impact on the performance of the ant colony algorithm. The basic parameters that are used in ACO algorithms are; the relati...

In the Euclidean traveling salesman and buyers problem (TSBP), we are given a set of convex regions in d-dimensional space, and we wish to nd a minimum-cost tour that visits all the regions. The cost of a tour depends on the length of the tour itself and on the distance that buyers within each region need to travel to meet the salesman. We show that constantfactor approximations to the TSBP and...

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In this paper we revisit the idea of relating the genetic code to a Gray code. This idea was originally fostered by Rosemary Swanson as a “unifying concept for the amino acid code”. We show that cyclic arrangements of the codons which are different from the one proposed by Swanson, but which are still based on the principle of minimal change, yield a better grouping of the amino acids by simila...

Two instances of the traveling salesman problem, on the same node set (1,2 n} but with different cost matrices C and C , are equivalent iff there exist {a, hi:-1, n} such that for any 1 _ i, j _ n, j, C(i, j) C(i,j) q-at -bj [7]. One ofthe well-solved special cases of the traveling salesman problem (TSP) is the convex-hull-and-line TSP. We extend the solution scheme for this class of TSP given ...