Perspectives of Monge properties in optimization
Discrete Applied Mathematics
Convex quadratic and semidefinite programming relaxations in scheduling
Journal of the ACM (JACM)
The Hardness of Metric Labeling
FOCS '04 Proceedings of the 45th Annual IEEE Symposium on Foundations of Computer Science
A branch and cut algorithm for hub location problems with single assignment
Mathematical Programming: Series A and B
Adapting polyhedral properties from facility to hub location problems
Discrete Applied Mathematics - The fourth international colloquium on graphs and optimisation (GO-IV)
A Linear Programming Formulation and Approximation Algorithms for the Metric Labeling Problem
SIAM Journal on Discrete Mathematics
A study of the quadratic semi-assignment polytope
Discrete Optimization
On dependent randomized rounding algorithms
Operations Research Letters
Algorithm for single allocation problem on hub-and-spoke networks in 2-dimensional plane
ISAAC'11 Proceedings of the 22nd international conference on Algorithms and Computation
Optimizing client assignment for enhancing interactivity in distributed interactive applications
IEEE/ACM Transactions on Networking (TON)
Computers and Industrial Engineering
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This paper deals with a single allocation problem in hub-and-spoke networks. We present a simple deterministic 3-approximation algorithm and randomized 2-approximation algorithm based on a linear relaxation problem and a randomized rounding procedure. We handle the case where the number of hubs is three, which is known to be NP-hard, and present a (5/4)-approximation algorithm. The single allocation problem includes a special class of the metric labeling problem, defined by introducing an assumption that both objects and labels are embedded in a common metric space. Under this assumption, we can apply our algorithms to the metric labeling problem without losing theoretical approximation ratios. As a byproduct, we also obtain a (4/3)-approximation algorithm for an ordinary metric labeling problem with three labels.