The paper presents the structure of an open-source software tool that can solve an Optimal Network Reconfiguration problem for a distribution grid. The problem includes kinship constraints that permit to fully represe...
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ISBN:
(纸本)9798350378498;9788887237627
The paper presents the structure of an open-source software tool that can solve an Optimal Network Reconfiguration problem for a distribution grid. The problem includes kinship constraints that permit to fully represent the logics which are behind the principal distribution automation schemes adopted by Distributor System Operators to deal with the fault detection, isolation and recovery function. The algorithm is structured to be fully open-source and it is developed on a Python-based environment. The adopted network models are also open-source and based on the Open-DSS software. Results obtained on the model of a realistically sized MV primary distribution network are shown.
This research is dedicated to formulating a practical problem related to the assignment of oncology clinic routes. The objective is to schedule medical events for patients attending health centers, taking into account...
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ISBN:
(纸本)9798350373981;9798350373974
This research is dedicated to formulating a practical problem related to the assignment of oncology clinic routes. The objective is to schedule medical events for patients attending health centers, taking into account the variable demand and limited resources in this field. To achieve this, three types of solutions are considered. The first is an Online Scheduling Algorithm, which simulates a scheduling process based on medical routes and also includes its inverse version. The next is a mixed-integer linear programming (MILP) model. In this case, information is centralized, and patients are scheduled based on their requirements, minimizing delays in their appointments and/or medical treatments. These methodologies are compared with the current mode of assignment used. To test the previously proposed solutions, data provided by the Arturo Lopez Perez Foundation (FALP) will be used.
This paper addresses freight consolidation in rail transportation planning. Multiple demand destinations are served in a single trip to utilise the volume discount on freight rate. An efficient mixed-integerlinear pr...
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This paper addresses freight consolidation in rail transportation planning. Multiple demand destinations are served in a single trip to utilise the volume discount on freight rate. An efficient mixed-integer linear programming (MILP) based modelling framework is proposed to optimally allocate rail wagons to a given set of destinations considering the shipment options offered by Indian Railways. Twelve problem instances are derived using real data from an Indian food grain organisation and are solved to optimum using the CPLEX solver in quick time. The results indicate that multi-point orders can reduce the total transportation cost and ease the handling of shipments at terminals. (c) 2025 Published by Elsevier Ltd on behalf of Indian Institute of Management Bangalore. This is an open access article under the CC BY-NC-ND license (http://***/licenses/ by-nc-nd/4.0/)
In this work, we challenge the common assumption in truck-drone last-mile delivery that trucks and drones operate on a graph. Instead, we adopt a geometric approach, allowing the vehicles to operate in Euclidean space...
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In this work, we challenge the common assumption in truck-drone last-mile delivery that trucks and drones operate on a graph. Instead, we adopt a geometric approach, allowing the vehicles to operate in Euclidean space. Our proposed mixed-integerlinear program determines a collision-free trajectory for a drone in the Euclidean space with obstacles, where the drone is launched and recovered by moving vehicles. Compared to graph-based approaches, the advantages are: (a) Flexible launching and recovery: The drone can be launched and recovered from any position along the streets, rather than being limited to discrete points (i.e., nodes of a graph). (b) Continuous drone velocity: The drone velocity is a continuous variable, and the drone energy consumption depends directly on its velocity. (c) No-fly zones and obstacles: Trajectory planning is incorporated to ensure a collision-free flight (rather than considering detours as a predefined parameter). To the best of our knowledge, such a geometric approach is new in truck-drone last-mile delivery. In our computational study we prove the usefulness of our geometric approach, as even large instances with up to 300 obstacles can be solved within reasonable computation time. In comparison to graph-based approaches, our geometric approach yields faster delivery times and enables the drone to reach customers that are out of its reach in graph-based approaches.
Multi-label neural networks are important in various tasks, including safety-critical tasks. Several works show that these networks are susceptible to adversarial attacks, which can remove a target label from the pred...
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ISBN:
(纸本)9783031747755;9783031747762
Multi-label neural networks are important in various tasks, including safety-critical tasks. Several works show that these networks are susceptible to adversarial attacks, which can remove a target label from the predicted label list or add a target label to this list. To date, no deterministic verifier determines the list of labels for which a multilabel neural network is locally robust. The main challenge is that the complexity of the analysis increases by a factor exponential in the multiplication of the number of labels and the number of predicted labels. We propose MuLLoC, a sound and complete robustness verifier for multi-label image classifiers that determines the robust labels in a given neighborhood of inputs. To scale the analysis, MuLLoC relies on fast optimistic queries to the network or to a constraint solver. Its queries include sampling and pair-wise relation analysis via numerical optimization and mixed-integer linear programming (MILP). For the remaining unclassified labels, MuLLoC performs an exact analysis by a novel mixed-integerprogramming (MIP) encoding for multi-label classifiers. We evaluate MuLLoC on convolutional networks for three multi-label image datasets. Our results show that MuLLoC classifies all labels as robust or not within 23.22 min on average and that our fast optimistic queries classify 96.84% of the labels.
The uncertainty mobility characteristics of electric vehicles (EVs) are a key factor that influence the charging station trade income with the power grid. In this paper, a hierarchical energy management strategy is pr...
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The uncertainty mobility characteristics of electric vehicles (EVs) are a key factor that influence the charging station trade income with the power grid. In this paper, a hierarchical energy management strategy is proposed for charging stations when large-scale EVs are considered. The traveling and parking mobility characteristics of EVs are first extracted by analyzing historical real-world traveling data. Then, a day-ahead power trade planning strategy between the grid and charging station to maximize incomes is developed by solving a mixed-integer linear programming problem. Furthermore, based on EV mobility characteristics, clusters are generated to classify different parking behaviors, where a mean field game-based decentralized charging control scheme for individual EVs in each cluster is employed. The target of the proposed optimal charging controller is to guarantee the charging power tracking performance and the power demand of individual EV at the terminal time for subsequent travel. Finally, simulations on MATLAB/Simulink platform are conducted to show the effectiveness of the proposed hierarchical energy management strategy.
The high emission intensity of coal-fired power plants (CFPP) leads to the inevitable next step towards energy transition, the coal phase-out. One challenge is the subsequent use of still-functioning assets. Re-purpos...
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The high emission intensity of coal-fired power plants (CFPP) leads to the inevitable next step towards energy transition, the coal phase-out. One challenge is the subsequent use of still-functioning assets. Re-purposing these assets avoids value loss and creates new opportunities for coal regions. Therefore, this study considers the sector coupling technologies Power-to-Gas (PtG) and Gas-to-Power (GtP) as re-purposing options. First, a multi-variable mixed-integer linear programming optimisation model is established. This model includes the participation of the plant in the current (2020) and future (2030, 2040) electricity and natural gas spot-markets and the balancing power market while fulfilling existing contracts, and allows for determining the re-purposing technologies' operating profiles. By applying a techno-economic analysis, investment recovery periods of the considered re-purposing technologies are assessed, which range between two (GtP) and over ten (PtG) years. A sensitivity analysis accounting for current energy prices and technological advancements reveals capital expenditure has the highest impact on this Return-On-Investment period. Additionally, a case study considering the Austrian energy grids is performed to account for the grid impact of integrating these technologies at former CFPP sites. Thus, it is found that the investigated sector coupling technologies have the potential to compensate for grid congestions even in profit-optimised operation.
It is crucial to efficiently schedule harvesting activities in order to reduce the delivered cost of logs. Mathematical models have been used to optimize the harvest scheduling at the operational level. However, in th...
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It is crucial to efficiently schedule harvesting activities in order to reduce the delivered cost of logs. Mathematical models have been used to optimize the harvest scheduling at the operational level. However, in the existing literature, the number of machines assigned for each activity at each cut block was not considered as a decision variable. Also, the impact of the slope of cut blocks on the precedence relationship between harvesting activities was not considered in tprevious studies. In this work, a mathematical model is developed with the possibility of assigning multiple machines for the same harvest activity at each cut block, considering the precedence relationship between activities based on the slope of cut blocks in order to minimize the total cost of harvesting. This work is an extension of our previous work on detailed scheduling of harvesting. The model is applied to the harvesting operations of a large forest company in Coastal British Columbia, Canada. The model's result for operating cost is only 3.3% higher than the lowest possible operating cost. Only one machine has an idle time. For the same case study, the total cost of the developed model is about 34% lower than that of the previous model.
This study addresses a permutation flow shop scheduling problem to minimize a linear combination of earliness, tardiness, and assigned due dates. The production environment under study has several real-world applicati...
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This study addresses a permutation flow shop scheduling problem to minimize a linear combination of earliness, tardiness, and assigned due dates. The production environment under study has several real-world applications, such as manufacturing, industrial maintenance, integrated production-distribution systems, potential disruptive environments, and other scenarios in which the due date is defined during sales negotiations with the customer. Four mixed-integer linear programming formulations were proposed and computationally evaluated, and their results were employed to measure the solution quality of the metaheuristics. Due to the complexity of the tackled problem, four coronavirus optimization algorithms based on recent optimization literature were implemented to solve it. A statistical analysis based on ANOVA (analysis of variance) and Tukey tests was performed to evaluate if the difference between the metaheuristics is statistically significant. The computational results demonstrated the superiority of the proposed metaheuristic Covid, especially in large-sized instances, outperforming an algorithm based on an iterated greedy algorithm (IGA) that we implemented for this problem.
This study addresses the integration of the railway and airline scheduling problems, in order to offer passengers smooth transfers between rail and air. This paper focuses on optimising the air and rail timetables at ...
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This study addresses the integration of the railway and airline scheduling problems, in order to offer passengers smooth transfers between rail and air. This paper focuses on optimising the air and rail timetables at 18 major European airports including three hubs and their associated train stations. A multimodal passenger demand simulation, using constraint programming and based on real data, is proposed. A typical week, from Monday to Saturday, of December 2019 is analysed. Ten passenger demand simulations are run for each day, resulting in 60 test instances that are publicly released. The air-rail timetable synchronisation is applied to these 60 instances. Three scenarios are tested in which each operator agrees to change its schedule or not. Results show that changing the schedule of only 13% of European flights by 11 min, and half of trains scheduled to stop at the three hubs of 17 min, on average, could increase the number of suitable connections for passengers by 60%. In addition, if both airlines and railway operators adapt their schedules, passenger comfort is improved and operator costs are reduced, even more so than with unilateral changes.
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