Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 37 for “"column generation"”.
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Column generation approaches to bus driver scheduling
… of valid duties, even for small problems. Column generation is a technique which implicitly considers a much larger number of duties, whilst retaining a much smaller working duty subset. A specialised column generation method is implemented within the existing set covering system, and the …
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Robust planning and scheduling using column generation
… are inherently difficult to solve. Recently, the column generation method has shown precedent in solving stochastic optimization problems. In this technique, the main optimization problem is decomposed into two more manageable sub problems which are then solved iteratively: the Restricted Master …
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Column generation approaches to the military airlift scheduling problem
… that uses integer linear programming (IP) with column generation to make the problem more tractable while incorporating the relevant characteristics. In our method, we decompose the problem into two steps: generating feasible aircraft routes, and solving the optimization model. By ensuring that …
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Large-Scale Optimization using Reinforcement Learning, Dynamic Programming, and Column Generation
… dynamic programming, reinforcement learning, and column generation as a practical way to address this need across a variety of settings. We begin by developing and refining our methodology within the context of reinforcement learning and dynamic programming. We then move on to the application of …
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Integer Programming for Discrete Optimization of the Agile Supply Chain Configuration Problem
… meeting capacity and distance constraints. The column generation approach is adopted to resolve the issue of limited scalability of the traditional LP formulation. Vendor cuts are proposed as a method to constrain distance inside the supply chain network. The proposed column generation …
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Managing radiotherapy treatment trade-offs using multi-criteria optimisation and data envelopment analysis
… delivery is then proposed. The method integrates column generation in the revised normal boundary intersection method, which projects a set of equidistant reference points onto the non-dominated set to form a representative set of non-dominated points. The delivery constraints are considered in …
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Enhanced Formulations for Minimax and Discrete Optimization Problems with Applications to Scheduling and Routing
… We present a novel modeling framework and column generation-based optimization approach for this challenging class of joint vehicle assembly-routing problems. In addition, we suggest several extensions to accommodate particular industrial restrictions where assembly sequence-dependent …
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Data-driven algorithms for operational problems
… management problem. We propose the Approximate Column Generation heuristic (ACG) and Potential Based algorithm (PB) for solving the Choice-based Deterministic Linear Program, an LP relaxation to the problem, to near-optimality. Both algorithms only assume the ability to approximate the …
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Sports analytics and optimization for team formation problems
… the team formation model and develop a column generation approach as well as a column generation-based heuristic, which provides a tight dual bound and high quality lower bound, respectively in order to close the optimality gap. This sets the foundation for a branch-and-price approach as …
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Optimizing Wildfire Suppression: A branch-and-price-and-cut approach
… objectives. To solve it, we develop a two-sided column generation algorithm that generates fire suppression plans and crew routes iteratively. We embed it into a branch-and-price-and-cut algorithm to retrieve an optimal integer solution, using novel special-purpose cuts that augment …
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Modeling and algorithmic development of a staff scheduling problem
… constraint which can be solved using the column generation technique. An inherent characteristic of this problem that makes it different from other set partitioning problems is that the arrival time and scheduled departure tin1e is different for different trucks. We illustrate the model …
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A linear programming approach for synthesizing origin-destination (O-D) trip tables based on a partial set of link traffic volumes
… resembles a target trip table. A modified column generation technique is employed to solve the problem. The methodology also accommodates a specified prior or target trip table, and drives the solution toward a tendency to match this table using user controlled parameters. The limitation of …
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Novel Approaches for Some Stochastic and Deterministic Scheduling Problems
… Next, we develop a new method for scenario generation that is computationally competitive and that assures attainment of an exact lower bound. Our approach is based on discretization of random parameter distributions of job processing times. We use the idea of Recursive Stratified Sampling …
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Mixed integer linear programming approach for solving assembly scheduling problems
… which in turn helps reduce the makespan. Column generation method has been used to solve the problem. Subproblem generates solution sets and the master problem selects from the set of generated solutions by the subproblem. Randomly generated problems with up to 100 assembly operations, 100 …
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Topics in Packing and Scheduling
… We propose a set covering formulation and a column generation algorithm to solve its linear relaxation, providing efficient pricing algorithms for the studied cases. To obtain integer solutions, we extend the column generation approach using branch-and-price. In Chapter 4, we study a …
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MATHEMATICAL PROGRAMMING METHODS FOR PARTIALLY UNDEFINED OPTIMIZATION MODELS
… usando programmazione lineare misto-intera e column generation; - apprendimento di vincoli interattivo – ideiamo algoritmi per risolvere programmi lineari 0-1 con vincoli mancanti ed imparare vincoli surrogati, usando un approccio basato su oracolo ispirato a tecniche di apprendimento attivo; …
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Optimizing Urban Air Mobility Operations in a Corridor Network
… structure at the flight level. We propose a column generation algorithm to decompose vehicle dispatching decisions in a master problem and flight trajectories in a pricing problem, using a tailored backward label-setting algorithm. This methodology scales to practical instances, with up to 50 …
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Solving Large Scale Crew Pairing Problems
… applies preprocessing techniques, cutting plane generation methods, and heuristics which are suitable for crew pairing problems. The implementation can solve small and medium sized problems. However, for large problems, a branch-and-price approach is necessary to cope with huge constraint …
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Branch-and-Price for Prescriptive Contagion Analytics
… on: (i) a set partitioning reformulation; (ii) a column generation decomposition; (iii) a novel state clustering algorithm for discrete-decision continuous-state dynamic programming; and (iv) a novel tri-partite branching scheme to circumvent non-linearities. Extensive experiments show that the …
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Logistics service network design : models, algorithms, and applications
… We introduce a disaggregate information-enhanced column generation approach for this problem that reduces the number of variables to be considered in the integer program from hundreds of thousands to only thousands, allowing us to solve previously unsolvable problem instances. The second problem …
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