Petrica C. Pop

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A well known N P-hard problem called the Generalized Traveling Salesman Problem (GTSP) is considered. In GTSP the nodes of a complete undirected graph are partitioned into clusters. The objective is to find a minimum cost tour passing through exactly one node from each cluster. An exact exponential time algorithm and an effective meta-heuristic algorithm(More)
We consider the Railway Traveling Salesman Problem (RTSP) in which a salesman using the railway network wishes to visit a certain number of cities to carry out his/her business, starting and ending at the same city, and having as goal to minimize the overall time of the journey. RTSP is an N P-hard problem. Although it is related to the Generalized(More)
The generalized traveling salesman problem (GTSP) is an NP-hard problem that extends the classical traveling salesman problem by partitioning the nodes into clusters and looking for a minimum Hamiltonian tour visiting exactly one node from each cluster. In this paper, we combine the consultant-guided search technique with a local-global approach in order to(More)
The idea of sensitivity in ant colony systems has been exploited in hybrid ant-based models with promising results for many combinatorial optimization problems. Heterogeneity is induced in the ant population by endowing individual ants with a certain level of sensitivity to the pheromone trail. The variable pheromone sensitivity within the same population(More)
In this paper, we consider the selective graph coloring problem. Given an integer k ≥ 1 and a graph G = (V, E) with a partition V1,. .. , Vp of V , it consists in deciding whether there exists a set V * in G such that |V * ∩ Vi| = 1 for all i ∈ {1,. .. , p}, and such that the graph induced by V * is k-colorable. We investigate the complexity status of this(More)