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Permanent link (DOI): https://doi.org/10.7939/R3PT1Q
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Approximation Algorithms for some Min-max Vehicle Routing Problems Open Access
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- Type of item
- Degree grantor
University of Alberta
- Author or creator
- Supervisor and department
Salavatipour, Mohammad (Computing Science)
- Examining committee member and department
Elmallah, Ehab (Computing Science)
Hayward, Ryan (Computing Science)
Department of Computing Science
- Date accepted
- Graduation date
Master of Science
- Degree level
In this thesis, we consider min-max vehicle routing problems, specifically min-max tour cover and star cover problems. Given a metric (V,c) and a number k, a set of tours (respectively stars) in G is called a k-tour cover (respectively k-star cover), if they cover all the vertices of G. In the rooted variant, the locations of the roots are given in the input.
In Chapter 2, we improve on the approximation ratios of tour cover problems. We present algorithms that improve the approximation ratios of rooted and unrooted min-max k-tour cover problems to (7+epsilon) and (16/3+epsilon) respectively.
In Chapter 3, we study the unrooted min-max k-star cover problem and improve the bi-criteria approximation ratio to (O(1/epsilon), 1+epsilon). For the line metric, we present a QPTAS, and in the special case that the stars are non-crossing, we present a PTAS. Then, we show that the problem is APX-hard on the Euclidean metric.
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