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Your search keyword '"Afrashteh, Esmaeil"' showing total 14 results
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6. Optimal Algorithms for Integer Inverse Undesirable p-Median Location Problems on Weighted Extended Star Networks

Author

Afrashteh, Esmaeil, Alizadeh, Behrooz, and Baroughi, Fahimeh

Abstract

This paper is concerned with the problem of modifying the edge lengths of a weighted extended star network with nvertices by integer amounts at the minimum total cost subject to be given modification bounds so that a set of pprespecified vertices becomes an undesirable p-median location on the perturbed network. We call this problem as the integer inverse undesirable p-median location model. Exact combinatorial algorithms with $$ {\mathcal {O}}\left( p^2 n \log n\right) $$ Op2nlogn and $${{\mathcal {O}}}\left( p^{2}(n \log n+ n \log \eta _{\max })\right) $$ Op2(nlogn+nlogηmax) running times are proposed for solving the problem under the weighted rectilinear and weighted Chebyshev norms, respectively. Furthermore, it is shown that the problem under the weighted sum-type Hamming distance with uniform modification bounds can be solved in $$ {\mathcal {O}}(p^2n \log n)$$ O(p2nlogn) time.

Published
2024
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12. Optimal algorithms for selective variants of the classical and inverse median location problems on trees.

Author

Afrashteh, Esmaeil, Alizadeh, Behrooz, and Baroughi, Fahimeh

Subjects
*MEDIAN (Mathematics), *TREE graphs, *ALGORITHMS, *POINT set theory, *TREES, *COMBINATORIAL optimization
Abstract

This paper is concerned with selective variants of the classical and inverse median location problems on tree graphs in which the set of existing customer points and the set of candidate facility locations are assumed to be two selective subsets of the vertices of the underlying tree. In the classical selective median location problem, the aim is to find the best location for establishing a facility such that the sum of (weighted) distances from the customers to the facility is minimized. However, the task of the corresponding inverse model is to augment or reduce the edge lengths at the minimum total cost until a predetermined facility location becomes a selective median of the underlying tree. We propose a novel optimal algorithm with linear time complexity for the classical selective model. Moreover, optimal approaches with time complexities are developed for solving the inverse selective median location problem on the given tree graph under different cost norms. [ABSTRACT FROM AUTHOR]

Published
2019
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