Search results for "Matheuristic"
showing 10 items of 10 documents
Randomized heuristics for the Capacitated Clustering Problem
2017
In this paper, we investigate the adaptation of the Greedy Randomized Adaptive Search Procedure (GRASP) and Iterated Greedy methodologies to the Capacitated Clustering Problem (CCP). In particular, we focus on the effect of the balance between randomization and greediness on the performance of these multi-start heuristic search methods when solving this NP-hard problem. The former is a memory-less approach that constructs independent solutions, while the latter is a memory-based method that constructs linked solutions, obtained by partially rebuilding previous ones. Both are based on the combination of greediness and randomization in the constructive process, and coupled with a subsequent l…
The collaborative consistent vehicle routing problem with workload balance
2021
Abstract The rising competition in the logistics sector forces companies to be more economically efficient. One of the major sources of inefficiency is the incomplete usage of available resources, such as vehicles’ capacities. Mechanism that allow to better exploit such resources by enabling carrier collaborations are on the rise. Our study examines a centrally organized multi-period collaborative vehicle routing problem, where carriers can exchange customers who have to be serviced on a regular basis. Collaborations, where carriers serve frequent customers, are supposed to face the problem of (i) time consistency in terms of visiting time, and of (ii) service consistency. The latter ensure…
The on-demand warehousing problem
2022
Warehouses are key elements of supply chain networks, and great attention is paid to increase their efficiency. Highly volatile space requirements are enablers of innovative resource sharing concepts, where warehouse capacities are traded on online platforms. In this context, our paper introduces the on-demand warehousing problem from the perspective of platform providers. The objective prioritises demand–supply matching with maximisation of the number of transactions. If there is a tie, the secondary objective maximises the number of suppliers matched with at least one customer and the number of customers that have matches within a specific threshold with respect to the minimum achievable …
Combining workload balance and patient priority maximisation in operating room planning through hierarchical multi-objective optimisation
2022
Abstract Previous analysis suggested the opportunity to consider the preferences of different stakeholders (hospital, patients, doctors and nurses) through the adoption of both patient priority maximisation and workload balance as performance criteria. The aim of this paper is to develop an effective and efficient solution approach for the operating room planning and scheduling capable to take into account the patient priority maximisation and workload balance criteria at the same time. This work is inspired by the need of a deeper understanding of the quality of the solutions obtained when a combination of the two criteria leads the OR planning decisions. Starting from a hierarchical multi…
Vehicle routing with private and shared delivery locations
2021
Abstract The rapid growth of e-commerce has led to an increase of home delivery requests. Providing efficient distribution systems for services on the last mile has become a challenging issue for logistics companies, where a trade-off between the classical approaches, attended home delivery (AHD) and usage of shared delivery locations (SDLs) has been identified. AHD provides a higher quality of service but implies very high costs for the company, while usage of SDL requires customers to perform the very last mile by themselves. For companies, this bears the risk of a decrease in the perceived service quality. However, due to consolidation effects, transportation costs can be considerably mi…
Solving the length constrained K-drones rural postman problem
2021
[EN] In this paper we address the Length Constrained K-Drones Rural Postman Problem (LC K-DRPP). This is a continuous optimization problem where a fleet of homogeneous drones have to jointly service (traverse) a set of (curved or straight) lines of a network. Unlike the vehicles in classical arc routing problems, a drone can enter a line through any of its points, service a portion of that line, exit through another of its points, then travel directly to any point on another line, and so on. Moreover, since the range of the drones is restricted, the length of each route is limited by a maximum distance. Some applications for drone arc routing problems include inspection of pipelines, railwa…
Hybridizing large neighborhood search and exact methods for generalized vehicle routing problems with time windows
2021
International audience; Delivery options are at the heart of the generalized vehicle routing problem with time windows (GVRPTW) allowing that customer requests are shipped to alternative delivery locations which can also have different time windows. Recently, the vehicle routing problem with delivery options was introduced into the scientific literature. It extends the GVRPTW by capacities of shared locations and by specifying service-level constraints defined by the customers' preferences for delivery options. The vehicle routing problem with delivery options also generalizes the vehicle routing problem with home roaming delivery locations and the vehicle routing problem with multiple time…
The Heterogeneous Fleet Vehicle Routing Problem with Draft Limits
2023
Over the past two decades, international maritime transport has been characterized by the advent of ever larger ships. This phenomenon is known as naval gigantism. If, on the one hand, naval gigantism allows to reduce transport costs by exploiting the economies of scale achievable by large ships, on the other hand, it implies a series of operational issues. Indeed, due to their large draft, such giant vessels are not allowed to enter small ports when fully or near-fully loaded, and in some cases, they cannot enter such small ports at all. In fact, their draft can strongly vary depending on the load on board. This implies restrictions for vessels in accessing ports, which impact not only at …
Bundle generation for last-mile delivery with occasional drivers
2022
In this paper, we present the vehicle routing problem (VRP) with occasional drivers (OD) and order bundles (OB). The problem VRP-OD-OB is an extension of the VRP-OD, where instead of assigning one customer per driver, drivers are assigned bundles of customers. To deal with the bundle-to-driver assignment, a bidding system is exploited, in which a company offers a set of bundles and the drivers raise their bids. These bids depend on features such as the drivers’ destination, flexibility in deviating from the shortest path, and willingness to offer service. To generate valuable bundles of customers, we propose two strategies: (i) an innovative approach based on the creation of corridors, and …
A matheuristic for the Team Orienteering Arc Routing Problem
2015
In the Team OrienteeringArc Routing Problem (TOARP) the potential customers are located on the arcs of a directed graph and are to be chosen on the basis of an associated profit. A limited fleet of vehicles is available to serve the chosen customers. Each vehicle has to satisfy a maximum route duration constraint. The goal is to maximize the profit of the served customers. We propose a matheuristic for the TOARP and test it on a set of benchmark instances for which the optimal solution or an upper bound is known. The matheuristic finds the optimal solutions on all, except one, instances of one of the four classes of tested instances (with up to 27 vertices and 296 arcs). The average error o…