An additive bounding procedure for the asymmetric travelling salesman problem
Mathematical Programming: Series A and B
When is the Assignment Bound Tight for the Asymmetric Traveling-Salesman Problem?
SIAM Journal on Computing
Exact solution of large-scale, asymmetric traveling salesman problems
ACM Transactions on Mathematical Software (TOMS)
Near-optimal intraprocedural branch alignment
Proceedings of the ACM SIGPLAN 1997 conference on Programming language design and implementation
Modeling and solving several classes of arc routing problems as traveling salesman problems
Computers and Operations Research
The Asymmetric Traveling Salesman Problem: Algorithms, Instance Generators, and Tests
ALENEX '01 Revised Papers from the Third International Workshop on Algorithm Engineering and Experimentation
The on-line asymmetric traveling salesman problem
Journal of Discrete Algorithms
The Traveling Salesman Problem: A Computational Study (Princeton Series in Applied Mathematics)
The Traveling Salesman Problem: A Computational Study (Princeton Series in Applied Mathematics)
Transforming asymmetric into symmetric traveling salesman problems
Operations Research Letters
Hi-index | 0.01 |
Many full truckload pick-up and delivery problems in the intermodal freight container transport industry can be modeled as Asymmetric Traveling Salesman Problems (ATSPs). Several authors have noted that while ATSPs are NP-hard, some instances are readily solved to optimality in only a short amount of time. Furthermore, the literature contains several references to the Stacker Crane Problem (SCP) as an ''easy'' problem amidst the ATSPs. We put this hypothesis to test by using statistical methods to build a model relating measurable distance matrix structures to the amount of time required by two existing exact solvers in finding solutions to over 500 ATSP instances. From this analysis we conclude that SCPs are not necessarily easier than other ATSPs, but a special subset of SCPs, termed drayage problems, are more readily solved. We speculate that drayage problems are ''easy'' because of a comparatively high number of zeros in symmetric locations within the distance matrix. In real-world drayage problems (i.e. the movement of containers a short distance to/from a port or rail terminal), these zeros correspond to the prevalence of jobs originating at or destined to a fixed number of freight terminals.