Simona Mancini | Politecnico di Torino (original) (raw)

Papers by Simona Mancini

Transportation Research Procedia, 2017

During the last decades, reverse logistics and reuse of products have received growing attention ... more During the last decades, reverse logistics and reuse of products have received growing attention as profitable and sustainable business strategies. Looking at the agrifood distribution sector, every day thousands of agrifood stores throw away large quantities of food product no longer suitable for sale. This "waste product", in the majority of cases, could still find new uses as animal feed or fertilizer. The return flow of food product is a typical problem of reverse logistics. This study proposes a new bi-modular scheme for managing the process of collection of "food waste" resulting from the agribusiness distribution sector and its subsequent distribution to livestock farms and collection centers located in the area of interest. The proposed management scheme consists of two modules:-module 1: to cluster the observed area into convenient collection sectors by means of clustering algorithms;-module 2: to identify optimal retrieval routes within each cluster by using Vehicle Routing models. The province of Cagliari in Sardinia (Italy) has been identified as test area. An extensive data collection process has been performed in order to collect the information necessary to portray the existing scenario. The following businesses have been recorded: grocery stores and supermarkets with at least 400 sqm of retail area, livestock farms with at least 200 heads of cattle, feed mills. A number of variables concerning location, type, size and demand data have been collected for each recorded unit.The management scheme has been implemented in a software platform and successfully applied in the test area. The outcome provides useful insights to stakeholders and suggests avenues for further research in the area in order to develop a more general and intuitive tool for managing reverse logistics processes in agrifood chains.

Transportation Research Part C: Emerging Technologies, 2016

Procedia - Social and Behavioral Sciences, 2014

In this paper we deal with container assignment optimization on an intermodal network. We propose... more In this paper we deal with container assignment optimization on an intermodal network. We propose a linear programming model, following a frequency based approach, addressing both the maritime and the inland component, and taking into account custom times at ports and service frequencies. The proposed arc-based formulation, in which only variables related to arcs which actually exist are explicitly created, is particularly suitable for very large but sparse networks, typical in maritime long distance transport, because it allows strongly reducing the number of variables involved. Finally, we discuss computational results obtained on a real size instance.

Operations Research/Computer Science Interfaces Series, 2013

We propose a meta-heuristic based on greedy randomized adaptive search procedure (GRASP) combined... more We propose a meta-heuristic based on greedy randomized adaptive search procedure (GRASP) combined with path relinking to address the two-echelon vehicle routing problem (2E-VRP), an extension of the capacitated vehicle routing problem (CVRP) in which the delivery from a single depot to customers is achieved by routing and consolidating the freight through intermediate depots called satellites. The problem is treated by separating the depot-to-satellite transfer and the satellite-to-customer delivery, and iteratively solving the two resulting routing subproblems, while adjusting the satellite workloads that link them. The meta-heuristic scheme consists of applying a GRASP and a local search (LS) procedures in sequence. Then, the resulting solution is linked to an elite solution by means of a path relinking procedure. To escape from infeasible solutions, which are quite common in this kind of problem, a feasibility search (FS) procedure is applied within path relinking. Extensive computational results on instances with up to 50 customers and 5 satellites show that the meta-heuristic is able to improve literature results, both in efficiency and accuracy.

Transport Problems, 2019

Roll-on Roll-of (Ro-Ro) transport is one of the primary options EU policy is focusing on for deve... more Roll-on Roll-of (Ro-Ro) transport is one of the primary options EU policy is focusing on for developing intermodal transport and MOS initiatives, aimed at reducing road transport (especially trucks). In line with EU guidelines, this study proposes an integrated and optimized network scheme for the maritime Ro-Ro freight services currently operating in the Italian Tyrrhenian area to improve the overall supply of shipping services. The methodological approach used is based on the integration of the timetables and frequencies of existing freight shipping services using an original mathematical model that assigns demand flows to the network while trying to minimize a multi-objective function composed of a weighted sum of travel times and tariffs. Quantitative results show the positive impact generated by rescheduling and coordinating liner shipping and demonstrate how a 'Tyrrhenian network system' considered as a whole would be more attractive than the single services taken collectively.

IEEE Access

In this paper, we consider the problem of completely flying over an area just hit by an earthquak... more In this paper, we consider the problem of completely flying over an area just hit by an earthquake with a fleet of Unmanned Aerial Vehicles (UAVs) to opportunely direct rescue teams. The cooperation between UAVs ensures that the search for possible survivors can be faster and more effective than the solutions currently implemented by civil protection. To study this scenario, we introduce the Cover by Multitrips with Priorities (CMP) problem, which tries to keep into account all the main real-life issues connected to the flight and coordination of the UAVs. We conduct a theoretical study to estimate the best number of UAVs and additional batteries, to give indications to the organization that leads the rescue teams to be able to guarantee rapid and effective rescue. Finally, based on some theoretical considerations, we propose some heuristics that tackle the problem of flying over the whole area with a fleet of UAVs in the shortest possible time. Simulations show that they work efficiently in both the proposed scenarios and provide better performance than previous solutions once they are arranged to work in our scenarios. The main advantages of our approach w.r.t. the current drone-based solutions used by the civil defense are that UAVs do not need drivers so the time of all available rescue workers can be invested in doing something else. In our model, we take into account that some sites (e.g. buildings with a high fire risk or schools and hospitals) have a higher priority and must be inspected first, and the possibility that UAVs can make a decision based on what they detect. Finally, our approach allows UAVs to collaborate so that the same sites will be flown over exactly once in order to speed up the rescue mission.

Springer Proceedings in Mathematics & Statistics

Operating Rooms (ORs) are one of the highest cost drivers of hospital budget and one of the highe... more Operating Rooms (ORs) are one of the highest cost drivers of hospital budget and one of the highest source of income. Several performance criteria have been reported to lead and to evaluate the OR planning decisions. Usually, patient priority maximisation and OR utilisation maximisation are the most used objectives in literature. On the contrary, the workload balance criteria, which leads to a smooth ward stay beds occupancy seems less used in literature. In this paper we propose a hierarchical multi-objective optimisation model for bed levelling and patient priority maximisation for the combined Master Surgical Scheduling and Surgical Cases Assignment problems. The aim of this work is to develop a methodology for OR planning and scheduling capable to take into account such different performance criteria.

In this paper we address the Two-Echelon Vehicle Routing Problem (2E-VRP), the variant of VRP whe... more In this paper we address the Two-Echelon Vehicle Routing Problem (2E-VRP), the variant of VRP where freight is delivered from depots to intermediate satellites, and then it is delivered to customers while minimizing the global routing costs of the overall two-echelon network. The goal of this work is to address more realistic situations in urban freight delivery where the travel costs are not only given by distances, but also by other components, like fixed costs for using the arcs, operational costs, and environmental costs. We introduce a generalized travel cost that may combine different components, e.g., operational, environmental, congestion, etc. We then analyze how the different components of the generalized cost affect the satellite location in the 2E-VRP and whether and under which conditions the Two-Echelon approach dominates the Single-Echelon one. © 2012 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of the 7th International Conference on Ci...

Operating Rooms (ORs) are one of the highest cost drivers of hospital budget and one of the highe... more Operating Rooms (ORs) are one of the highest cost drivers of hospital budget and one of the highest source of income. Several performance criteria have been reported to lead and to evaluate the OR planning decisions. Usually, patient priority maximisation and OR utilisation maximisation are the most used objectives in literature. On the contrary, the workload balance criteria, which leads to a smooth ward stay beds occupancy seems less used in literature. In this paper we propose a hierarchical multi-objective optimisation model for bed levelling and patient priority maximisation for the combined Master Surgical Scheduling and Surgical Cases Assignment problems. The aim of this work is to develop a methodology for OR planning and scheduling capable to take into account such different performance criteria.

1. Motivation The transportation industry has become a very competitive environment. While the nu... more 1. Motivation The transportation industry has become a very competitive environment. While the number of competitors has grown considerably, customers have become more and more demanding. Therefore, companies need to provide efficient transportation services at low prices to be competitive on the market. For this reason, profit margins have sensibly declined. To increase their efficiency, carriers can establish collaborations in which they share their fleets with the aim to maximize their profit and reduce operational costs. Collaborations may be centralized, where decisions are made by an external decision maker having complete information. In decentralized collaborations, no such fully informed decision maker exists. Obviously, centralized collaborations allow a better exploitation of the available resources. Collaborations or shared resources do not only increase efficiency of logistics providers, but are also demanded by other stakeholders. Residents, for example, benefit from e...

In the last decades , the increasing quality of services requested by the cust omer, yields to th... more In the last decades , the increasing quality of services requested by the cust omer, yields to the necessity of optimizing the whole distribution process. This goal may be achieved through a smart exploitation of existing resources other than a clever planning of the whole distribution process. For doing that, it is necessary to enha nce goods consolidation. One of the most efficient way to implement it is to adopt Multi - Echelon distribution systems which are very common in City Logistic context, in which they allow to keep large trucks from the city center, with strong environmental a dvantages . The aim of the paper is to review routing problems arising in City Logistics , in which multi - e chelon distribution systems are involved: the Two Echelon Location Routing Problem ( 2E - LRP) , the Two Echelon Vehicle Routing Problem (2E - VRP) and Truck and Trailer Routing Problem (TTRP), and to discuss literature on optimization methods, both exact and heuristic, developed to address ...

Computers & Operations Research

Abstract The rapid growth of e-commerce has led to an increase of home delivery requests. Providi... more 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 mitigated. We propose a mixed delivery approach, which combines AHD and SDL usage in an innovative way. Customers can either be served at home during their preferred time window, or they can be asked to pick up their parcel at one of the SDLs. For each customer served using an SDL, the company pays a compensation price in order to reduce the perceived decrease in service quality. The newly introduced decision problem is formulated mathematically. We propose two matheuristics to efficiently solve large instances. In an extensive numerical study, we show that the new approach clearly outperforms standard ones. We observe an increase in solution quality of up to 40%, while customers’ perceived quality of service is not affected. Additionally, the results reveal that the obtained improvements are robust for different customer-specific time-window preferences, accepted travel times needed to reach an SDL, and different compensation schemes.

Uncertainty Management with Fuzzy and Rough Sets

This paper introduces a route-planning problem with applications in tourism. The goal of the Tour... more This paper introduces a route-planning problem with applications in tourism. The goal of the Tourist Trip Design Problem is to maximize the number of points of interest to visit. We propose a new variant, in our view more realistic, where on the one hand, the points of interest are clustered in various categories and on the other, the scores and travel time constraints are fuzzy. In this work time constraints are modeled as fuzzy. A fuzzy optimization approach and an efficient greedy randomized adaptive search procedure are applied to solve the problem. The computational experiments indicate that this soft computing approach is able to find significant solutions.

European Journal of Operational Research

Computers & Industrial Engineering

Computers & Operations Research

In this paper, we propose a metaheuristic approach for efficiently solving the Green Vehicle Rout... more In this paper, we propose a metaheuristic approach for efficiently solving the Green Vehicle Routing Problem with Capacitated Alternative Fuel Stations (G-VRP-CAFS). The G-VRP-CAFS, a variant of the traditional G-VRP, aims at routing a fleet of Alternative Fuel Vehicles (AFVs), based at a common depot, in order to serve a set of customers, minimizing the total travel distance. Due to the limited autonomy of the AFVs, some stops at Alternative Fuel Stations (AFSs) may be necessary during each trip. Unlike the G-VRP, in the G-VRP-CAFS, the AFS capacity, in terms of fueling pumps that are simultaneously available, is realistically assumed limited. For such a problem, we design an Iterated Local Search algorithm, in order to obtain good quality solutions in reasonable amount of time also on real-life alike case studies. Preliminary results, carried out on a set of benchmark instances taken from the literature, are promising.

Computers & Industrial Engineering

Abstract The planning of itineraries for tourist cruises is a complex process where several featu... more Abstract The planning of itineraries for tourist cruises is a complex process where several features, such as vessel selection, port services, and requirements for point of interest to be inserted in each tour, must be addressed. The present work models the tour planning problem as a variant of vehicle routing problem considering specific constraints such as: fixed number of tours, not mandatory visits of all nodes, multiple time windows, possibility to choose among different travel speed values. The resulting mathematical formulation lead to a complex model for which commercial solvers fail to solve large instances in a reasonable time. To overcome this issue we propose a Large Neighborhood Search based matheuristic, in which an over-constrained version of the mathematical model is used to exhaustively and efficiently explore large neighborhoods. Test results performed on a real case instances demonstrate effectiveness of the proposed approach.

Transportation Research Procedia, 2017

During the last decades, reverse logistics and reuse of products have received growing attention ... more During the last decades, reverse logistics and reuse of products have received growing attention as profitable and sustainable business strategies. Looking at the agrifood distribution sector, every day thousands of agrifood stores throw away large quantities of food product no longer suitable for sale. This "waste product", in the majority of cases, could still find new uses as animal feed or fertilizer. The return flow of food product is a typical problem of reverse logistics. This study proposes a new bi-modular scheme for managing the process of collection of "food waste" resulting from the agribusiness distribution sector and its subsequent distribution to livestock farms and collection centers located in the area of interest. The proposed management scheme consists of two modules:-module 1: to cluster the observed area into convenient collection sectors by means of clustering algorithms;-module 2: to identify optimal retrieval routes within each cluster by using Vehicle Routing models. The province of Cagliari in Sardinia (Italy) has been identified as test area. An extensive data collection process has been performed in order to collect the information necessary to portray the existing scenario. The following businesses have been recorded: grocery stores and supermarkets with at least 400 sqm of retail area, livestock farms with at least 200 heads of cattle, feed mills. A number of variables concerning location, type, size and demand data have been collected for each recorded unit.The management scheme has been implemented in a software platform and successfully applied in the test area. The outcome provides useful insights to stakeholders and suggests avenues for further research in the area in order to develop a more general and intuitive tool for managing reverse logistics processes in agrifood chains.

Transportation Research Part C: Emerging Technologies, 2016

Procedia - Social and Behavioral Sciences, 2014

In this paper we deal with container assignment optimization on an intermodal network. We propose... more In this paper we deal with container assignment optimization on an intermodal network. We propose a linear programming model, following a frequency based approach, addressing both the maritime and the inland component, and taking into account custom times at ports and service frequencies. The proposed arc-based formulation, in which only variables related to arcs which actually exist are explicitly created, is particularly suitable for very large but sparse networks, typical in maritime long distance transport, because it allows strongly reducing the number of variables involved. Finally, we discuss computational results obtained on a real size instance.

Operations Research/Computer Science Interfaces Series, 2013

We propose a meta-heuristic based on greedy randomized adaptive search procedure (GRASP) combined... more We propose a meta-heuristic based on greedy randomized adaptive search procedure (GRASP) combined with path relinking to address the two-echelon vehicle routing problem (2E-VRP), an extension of the capacitated vehicle routing problem (CVRP) in which the delivery from a single depot to customers is achieved by routing and consolidating the freight through intermediate depots called satellites. The problem is treated by separating the depot-to-satellite transfer and the satellite-to-customer delivery, and iteratively solving the two resulting routing subproblems, while adjusting the satellite workloads that link them. The meta-heuristic scheme consists of applying a GRASP and a local search (LS) procedures in sequence. Then, the resulting solution is linked to an elite solution by means of a path relinking procedure. To escape from infeasible solutions, which are quite common in this kind of problem, a feasibility search (FS) procedure is applied within path relinking. Extensive computational results on instances with up to 50 customers and 5 satellites show that the meta-heuristic is able to improve literature results, both in efficiency and accuracy.

Transport Problems, 2019

Roll-on Roll-of (Ro-Ro) transport is one of the primary options EU policy is focusing on for deve... more Roll-on Roll-of (Ro-Ro) transport is one of the primary options EU policy is focusing on for developing intermodal transport and MOS initiatives, aimed at reducing road transport (especially trucks). In line with EU guidelines, this study proposes an integrated and optimized network scheme for the maritime Ro-Ro freight services currently operating in the Italian Tyrrhenian area to improve the overall supply of shipping services. The methodological approach used is based on the integration of the timetables and frequencies of existing freight shipping services using an original mathematical model that assigns demand flows to the network while trying to minimize a multi-objective function composed of a weighted sum of travel times and tariffs. Quantitative results show the positive impact generated by rescheduling and coordinating liner shipping and demonstrate how a 'Tyrrhenian network system' considered as a whole would be more attractive than the single services taken collectively.

IEEE Access

In this paper, we consider the problem of completely flying over an area just hit by an earthquak... more In this paper, we consider the problem of completely flying over an area just hit by an earthquake with a fleet of Unmanned Aerial Vehicles (UAVs) to opportunely direct rescue teams. The cooperation between UAVs ensures that the search for possible survivors can be faster and more effective than the solutions currently implemented by civil protection. To study this scenario, we introduce the Cover by Multitrips with Priorities (CMP) problem, which tries to keep into account all the main real-life issues connected to the flight and coordination of the UAVs. We conduct a theoretical study to estimate the best number of UAVs and additional batteries, to give indications to the organization that leads the rescue teams to be able to guarantee rapid and effective rescue. Finally, based on some theoretical considerations, we propose some heuristics that tackle the problem of flying over the whole area with a fleet of UAVs in the shortest possible time. Simulations show that they work efficiently in both the proposed scenarios and provide better performance than previous solutions once they are arranged to work in our scenarios. The main advantages of our approach w.r.t. the current drone-based solutions used by the civil defense are that UAVs do not need drivers so the time of all available rescue workers can be invested in doing something else. In our model, we take into account that some sites (e.g. buildings with a high fire risk or schools and hospitals) have a higher priority and must be inspected first, and the possibility that UAVs can make a decision based on what they detect. Finally, our approach allows UAVs to collaborate so that the same sites will be flown over exactly once in order to speed up the rescue mission.

Springer Proceedings in Mathematics & Statistics

Operating Rooms (ORs) are one of the highest cost drivers of hospital budget and one of the highe... more Operating Rooms (ORs) are one of the highest cost drivers of hospital budget and one of the highest source of income. Several performance criteria have been reported to lead and to evaluate the OR planning decisions. Usually, patient priority maximisation and OR utilisation maximisation are the most used objectives in literature. On the contrary, the workload balance criteria, which leads to a smooth ward stay beds occupancy seems less used in literature. In this paper we propose a hierarchical multi-objective optimisation model for bed levelling and patient priority maximisation for the combined Master Surgical Scheduling and Surgical Cases Assignment problems. The aim of this work is to develop a methodology for OR planning and scheduling capable to take into account such different performance criteria.

In this paper we address the Two-Echelon Vehicle Routing Problem (2E-VRP), the variant of VRP whe... more In this paper we address the Two-Echelon Vehicle Routing Problem (2E-VRP), the variant of VRP where freight is delivered from depots to intermediate satellites, and then it is delivered to customers while minimizing the global routing costs of the overall two-echelon network. The goal of this work is to address more realistic situations in urban freight delivery where the travel costs are not only given by distances, but also by other components, like fixed costs for using the arcs, operational costs, and environmental costs. We introduce a generalized travel cost that may combine different components, e.g., operational, environmental, congestion, etc. We then analyze how the different components of the generalized cost affect the satellite location in the 2E-VRP and whether and under which conditions the Two-Echelon approach dominates the Single-Echelon one. © 2012 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of the 7th International Conference on Ci...

Operating Rooms (ORs) are one of the highest cost drivers of hospital budget and one of the highe... more Operating Rooms (ORs) are one of the highest cost drivers of hospital budget and one of the highest source of income. Several performance criteria have been reported to lead and to evaluate the OR planning decisions. Usually, patient priority maximisation and OR utilisation maximisation are the most used objectives in literature. On the contrary, the workload balance criteria, which leads to a smooth ward stay beds occupancy seems less used in literature. In this paper we propose a hierarchical multi-objective optimisation model for bed levelling and patient priority maximisation for the combined Master Surgical Scheduling and Surgical Cases Assignment problems. The aim of this work is to develop a methodology for OR planning and scheduling capable to take into account such different performance criteria.

1. Motivation The transportation industry has become a very competitive environment. While the nu... more 1. Motivation The transportation industry has become a very competitive environment. While the number of competitors has grown considerably, customers have become more and more demanding. Therefore, companies need to provide efficient transportation services at low prices to be competitive on the market. For this reason, profit margins have sensibly declined. To increase their efficiency, carriers can establish collaborations in which they share their fleets with the aim to maximize their profit and reduce operational costs. Collaborations may be centralized, where decisions are made by an external decision maker having complete information. In decentralized collaborations, no such fully informed decision maker exists. Obviously, centralized collaborations allow a better exploitation of the available resources. Collaborations or shared resources do not only increase efficiency of logistics providers, but are also demanded by other stakeholders. Residents, for example, benefit from e...

In the last decades , the increasing quality of services requested by the cust omer, yields to th... more In the last decades , the increasing quality of services requested by the cust omer, yields to the necessity of optimizing the whole distribution process. This goal may be achieved through a smart exploitation of existing resources other than a clever planning of the whole distribution process. For doing that, it is necessary to enha nce goods consolidation. One of the most efficient way to implement it is to adopt Multi - Echelon distribution systems which are very common in City Logistic context, in which they allow to keep large trucks from the city center, with strong environmental a dvantages . The aim of the paper is to review routing problems arising in City Logistics , in which multi - e chelon distribution systems are involved: the Two Echelon Location Routing Problem ( 2E - LRP) , the Two Echelon Vehicle Routing Problem (2E - VRP) and Truck and Trailer Routing Problem (TTRP), and to discuss literature on optimization methods, both exact and heuristic, developed to address ...

Computers & Operations Research

Abstract The rapid growth of e-commerce has led to an increase of home delivery requests. Providi... more 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 mitigated. We propose a mixed delivery approach, which combines AHD and SDL usage in an innovative way. Customers can either be served at home during their preferred time window, or they can be asked to pick up their parcel at one of the SDLs. For each customer served using an SDL, the company pays a compensation price in order to reduce the perceived decrease in service quality. The newly introduced decision problem is formulated mathematically. We propose two matheuristics to efficiently solve large instances. In an extensive numerical study, we show that the new approach clearly outperforms standard ones. We observe an increase in solution quality of up to 40%, while customers’ perceived quality of service is not affected. Additionally, the results reveal that the obtained improvements are robust for different customer-specific time-window preferences, accepted travel times needed to reach an SDL, and different compensation schemes.

Uncertainty Management with Fuzzy and Rough Sets

This paper introduces a route-planning problem with applications in tourism. The goal of the Tour... more This paper introduces a route-planning problem with applications in tourism. The goal of the Tourist Trip Design Problem is to maximize the number of points of interest to visit. We propose a new variant, in our view more realistic, where on the one hand, the points of interest are clustered in various categories and on the other, the scores and travel time constraints are fuzzy. In this work time constraints are modeled as fuzzy. A fuzzy optimization approach and an efficient greedy randomized adaptive search procedure are applied to solve the problem. The computational experiments indicate that this soft computing approach is able to find significant solutions.

European Journal of Operational Research

Computers & Industrial Engineering

Computers & Operations Research

In this paper, we propose a metaheuristic approach for efficiently solving the Green Vehicle Rout... more In this paper, we propose a metaheuristic approach for efficiently solving the Green Vehicle Routing Problem with Capacitated Alternative Fuel Stations (G-VRP-CAFS). The G-VRP-CAFS, a variant of the traditional G-VRP, aims at routing a fleet of Alternative Fuel Vehicles (AFVs), based at a common depot, in order to serve a set of customers, minimizing the total travel distance. Due to the limited autonomy of the AFVs, some stops at Alternative Fuel Stations (AFSs) may be necessary during each trip. Unlike the G-VRP, in the G-VRP-CAFS, the AFS capacity, in terms of fueling pumps that are simultaneously available, is realistically assumed limited. For such a problem, we design an Iterated Local Search algorithm, in order to obtain good quality solutions in reasonable amount of time also on real-life alike case studies. Preliminary results, carried out on a set of benchmark instances taken from the literature, are promising.

Computers & Industrial Engineering

Abstract The planning of itineraries for tourist cruises is a complex process where several featu... more Abstract The planning of itineraries for tourist cruises is a complex process where several features, such as vessel selection, port services, and requirements for point of interest to be inserted in each tour, must be addressed. The present work models the tour planning problem as a variant of vehicle routing problem considering specific constraints such as: fixed number of tours, not mandatory visits of all nodes, multiple time windows, possibility to choose among different travel speed values. The resulting mathematical formulation lead to a complex model for which commercial solvers fail to solve large instances in a reasonable time. To overcome this issue we propose a Large Neighborhood Search based matheuristic, in which an over-constrained version of the mathematical model is used to exhaustively and efficiently explore large neighborhoods. Test results performed on a real case instances demonstrate effectiveness of the proposed approach.