Inventory management, vehicle routing, and delivery scheduling decisions are simultaneously considered in the context of the inventory routing problem. This paper focuses on the continuous-time version of this problem...
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In this paper we solve mixed-integerlinear programs (MILPs) via distributed asynchronous saddle point computation. To solve a MILP, we relax it with a linear program approximation. We first show that if the linear pr...
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In this paper, we proposed a conflict-free routing strategy combined with scheduling for Terminal Manoeuvring Area (TMA) multi-aircraft to guarantee a safe separation. By incorporating Standard Terminal Arrival Routes...
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In this paper, we proposed a conflict-free routing strategy combined with scheduling for Terminal Manoeuvring Area (TMA) multi-aircraft to guarantee a safe separation. By incorporating Standard Terminal Arrival Routes (STARs) as route constraints, a mixed-logic model is designed to maximize the runway throughput while ensuring minimum separation between aircraft and avoiding overtaking on each STARs segment. Control techniques such as speed recommendation and holding operations are employed to the model to address potential conflicts. Three different algorithms are developed to solve the model: branch and bound with mixed-integer linear programming, multi-agent pathfinding with constraint programming, and meta-heuristics with evolutionary neighborhood search. These algorithms are tested on multiple cases of varying scales. Finally, we demonstrate the advantages of the proposed three algorithms by simulating realistic scenarios and comparing the results with Singapore ADS-B (Automatic dependent Surveillance-Broadcast) historical dataset. In one hour testing, results show that our method could reduce the last aircraft landing time nearly 10 minutes and save more than 80 minutes for total flight travel times for all aircraft, as well as non-vectoring flight trajectories, which indicates its potential to be used as an auxiliary decision-making tool for Air Traffic Controllers (ATCOs).
The need for rapid and widespread deployment of new technologies to address climate change goals (e.g., deep, economy -wide decarbonization) presents new opportunities for advancing modular design strategies. Conventi...
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The need for rapid and widespread deployment of new technologies to address climate change goals (e.g., deep, economy -wide decarbonization) presents new opportunities for advancing modular design strategies. Conventional engineering approaches focus on unique designs for each installation, while missing opportunities for manufacturing standardization. Extending insights from the automotive industry, we optimize a platform of common unit module designs while simultaneously designing an entire family of process variants that make use of that platform. This reduces engineering effort, deployment timelines, and manufacturing costs. We propose a nonlinear generalized disjunctive programming formulation and convert this to an efficient mixed -integerlinearprogramming (MILP) formulation through discretization of the design space. We formulate our optimization in Pyomo with costing from IDAES, and we demonstrate the computational performance and solution quality on a water treatment desalination system from the PARETO framework and a carbon capture system built in Aspen Plus (R) as part of CCSI2.
This paper addresses the self-scheduling problem of determining the unit commitment status for power generation companies before submitting the hourly bids In a day-ahead market. The thermal unfit commitment model Is ...
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This paper addresses the self-scheduling problem of determining the unit commitment status for power generation companies before submitting the hourly bids In a day-ahead market. The thermal unfit commitment model Is formulated as a deterministic optimization problem where expected profit is maximized using the 0/1 mixed-integer linear programming technique. This approach allows precise modelling of non-convex variable cost, nonlinear start-up cost, ramp rate limits and minimum up and down time constraints for thermal units. Model Incorporates long-term bilateral contracts with contracted power and price patterns, as well as forecasted market hourly prices for day-ahead auction. Solution is achieved using the homogeneous and self-dual interior point method for linearprogramming as state of the art technique, with a branch and bound optimizer for integerprogramming. The effectiveness of the proposed model optimizing the thermal generation schedule Is demonstrated through the case study with detailed discussion.
The blood supply chain (BSC) is a complex system with optimization challenges, whose activities impact carbon emissions and the environment, especially with regard to the disposal of expired blood bag waste. This stud...
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Considering carbon emissions when making supply chain decisions has been an essential contributor for keeping this world more sustainable. This paper presents a mixed-integer linear programming (MILP) model to optimiz...
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Considering carbon emissions when making supply chain decisions has been an essential contributor for keeping this world more sustainable. This paper presents a mixed-integer linear programming (MILP) model to optimize production and transportation decision where the transportation activities involve a multimodal combination. The proposed mathematical model was aimed at minimizing the total costs incurred from supply chain activities as well as the emissions generated. Carbon cap is used to ensure that the emissions produced in the whole activities do not exceed the allowable limit. In this research, we address a multi-product, multi-plant, multi-departure, and arrival stations where multiple customers are to be served for multiple periods. The numerical tests show that the demand, carbon tax, and distance significantly affected the total emissions and the total costs. Interestingly, we observed that the decisions are much more affected by the logistical costs rather than the emission costs. The model presented in this paper can assist the decision makers to make production, delivery, and inventory decisions when multi-modal transportation is involved.
Collateral management involves the efficient monitoring and allocation of assets to mitigate credit risk in financial transactions and is crucial for institutions such as commercial banks, investments banks, and centr...
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This paper aims to study a new form of facility layout problem, in which the building has already been constructed and the specific room layout inside has been determined. Unlike the traditional facility layout proble...
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ISBN:
(纸本)9781479967735
This paper aims to study a new form of facility layout problem, in which the building has already been constructed and the specific room layout inside has been determined. Unlike the traditional facility layout problem, what we take into account is how to assign a certain number of rooms to a given number of departments with the purpose of maximizing the utilization rate of the rooms. This is equivalent to minimizing the total difference value between the extra area of different departments after satisfying their required area, thus reducing the space waste. To solve this special combinatorial optimization problem, we develop a mixed-integer linear programming (MILP) model. The model is solved using commercial software CPLEX12.6. Computational results on several randomly generated instances demonstrate the effectiveness of the proposed approach.
The efficient production of green energy plays an import role in modern economies. In this paper we address the optimization of cable connections between turbines in an offshore wind park. Different versions of this p...
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