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http://hdl.handle.net/11375/25846Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | Hassini, Elkafi | - |
| dc.contributor.author | Tamvada, Srinivas | - |
| dc.date.accessioned | 2020-10-02T13:37:45Z | - |
| dc.date.available | 2020-10-02T13:37:45Z | - |
| dc.date.issued | 2020 | - |
| dc.identifier.uri | http://hdl.handle.net/11375/25846 | - |
| dc.description.abstract | We propose solution strategies for hard Mixed Integer Programming (MIP) problems, with a focus on distributed parallel MIP optimization. Although our proposals are inspired by the Less-than-truckload (LTL) freight routing problem, they are more generally applicable to hard MIPs from other domains. We start by developing an Integer Programming model for the Less-than-truckload (LTL) freight routing problem, and present a novel heuristic for solving the model in a reasonable amount of time on large LTL networks. Next, we identify some adaptations to MIP branching strategies that are useful for achieving improved scaling upon distribution when the LTL routing problem (or other hard MIPs) are solved using parallel MIP optimization. Recognizing that our model represents a pseudo-Boolean optimization problem (PBO), we leverage solution techniques used by PBO solvers to develop a CPLEX based look-ahead solver for LTL routing and other PBO problems. Our focus once again is on achieving improved scaling upon distribution. We also analyze a technique for implementing subtree parallelism during distributed MIP optimization. We believe that our proposals represent a significant step towards solving big-data driven optimization problems (such as the LTL routing problem) in a more efficient manner. | en_US |
| dc.language.iso | en | en_US |
| dc.subject | Big-data driven optimization methods | en_US |
| dc.subject | Less-than-truckload freight routing | en_US |
| dc.title | Big-Data Driven Optimization Methods with Applications to LTL Freight Routing | en_US |
| dc.type | Thesis | en_US |
| dc.contributor.department | Computational Engineering and Science | en_US |
| dc.description.degreetype | Thesis | en_US |
| dc.description.degree | Doctor of Philosophy (PhD) | en_US |
| dc.description.layabstract | Less-than-truckload (LTL) freight transportation is a vital part of Canada's economy, with revenues running into billions of dollars and a cascading impact on many other industries. LTL operators often have to deal with large volumes of shipments, unexpected changes in traffic conditions, and uncertainty in demand patterns. In an industry that already has low profit margins, it is therefore vitally important to make good routing decisions without expending a lot of time. The optimization of such LTL freight networks often results in complex big-data driven optimization problems. In addition to the challenge of finding optimal solutions for these problems, analysts often have to deal with the complexities of big-data driven inputs. In this thesis we develop several solution strategies for solving the LTL freight routing problem including an exact model, novel heuristics, and techniques for solving the problem efficiently on a cluster of computers. Although the techniques we develop are inspired by LTL routing, they are more generally applicable for solving big-data driven optimization problems from other domains. Experiments conducted over the years in consultation with industry experts indicate that our proposals can significantly improve solution quality and reduce time to solution. Furthermore, our proposals open up interesting avenues for future research. | en_US |
| Appears in Collections: | Open Access Dissertations and Theses | |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| Tamvada_Srinivas_S_202008_phd.pdf | 1.8 MB | Adobe PDF | View/Open |
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