128 research outputs found

    New solution approaches for the Train Load Planning Problem

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    The present paper faces the train load planning problem in container terminals. The problem consists of assigning containers to rail wagons while maximizing the total priority of the containers loaded and minimizing the number of rehandles executed in the terminal yard. Two diferent heuristic approaches, based on an innovative way to compute weight limitations and on two 0/1 integer programming models, are proposed and compared on the basis of specifc key performance indicators. The heuristic approaches are compared using random generated instances based on real-world data. An extensive computational analysis has been performed

    System Dynamics Model For The Simulation Of A Non Multi Echelon Supply Chain: Analysis and Optimization Utilizing The Berkeley Madonna Software

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    — In today’s global market, managing the entire supply chain becomes a key factor for a successful business. World-class organizations realize that non-integrated manufacturing and distribution processes together with poor relationships with suppliers and customers are a huge limit for their success. One of the most important aspect affecting the performance of a supply chain is the management of inventories. Inventory management in the supply chain system is quite a complex issue because demand at the upstream stage is dependent on orders from the downstream stage, and the final downstream stage receives orders from the market in uncertain conditions. Uncertainty is one of the major obstacle which limits the creation of an effective supply chain inventory model, able to optimize times and costs. Being the management of a complex inventory model too difficult to analyze with traditional analytical mathematical methods, computer simulation is widely used to study this kind of problems. This paper has the goal of modeling a single echelon supply chain and optimizing its inventories levels so to reduce the bullwhip effect and consequently minimize the supply chain costs. The supply chain here proposed consists of five stages – customer, retailer, wholesaler, distributor and factory – and its modeling is carried out through a system dynamics approach, utilizing the Berkeley Madonna software

    Simulation of novel algorithms to reduce truck congestion at container terminals

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    Efficient managing truck flows has become a challenge for container terminals that have to maintain a high productivity while guaranteeing high service levels to truckers. Moreover, the increasing quantity of cargo to be handled in short time windows introduces congestion and security issues. This paper deals with the definition and simulation of various algorithms implementing a truck management system, with the objective or reducing congestion outside and inside the terminal, so guaranteeing security standards. An extensive simulation campaign has been performed on real data sets provided by an important Italian container terminal, demonstrating the effectiveness of the proposed mathematical approach in reducing terminal congestion and security issues. The designed methodology is general enough to be effectively applied in other container terminals realities located worldwide

    The expansion of the port of Genoa: the Rivalta Scrivia dry port

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    There are two main ways for a port to face the long-term increase in freight demand: a better usage of the current available port land or an enlargement to new port areas. Within this second solution is included the movement outside of the port’s borders of some activities currently carried out in the port, but not directly connected with the loading or unloading of goods. This relieves the territory and the port itself of the negative consequences (represented by the occupancy of scarce resources, such as the port areas) resulting from increased time and costs due to the handling of goods taking space and time from more value added activities and from the negative externalities associated with the presence of the port industry highly impacting the city fabric (such as congestion, atmospheric and acoustic pollution and space taken away from the city). This is the situation of the port of Genoa, where the particular orographic configuration of the territory and a large urbanization of the immediate proximity of the port property have forced the Genoa Port Authority to look for more space in the hinterland in order to manage the import/export of goods in the most efficient and effective way possible. This paper examines the case study of the Rivalta Scrivia dry port, located 75 km from Genoa along the railway line that links the Ligurian capital with the reference market. The need for more space at the service of Genoa port is confirmed by the analysis of the port demand, including both current and forecasted container traffic

    A rostering approach to minimize health risks for workers: An application to a container terminal in the Italian port of Genoa

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    The evolving safety regulation is pushing seaports to comply with safety measures for workers performing heavy loads handling and repetitive movements. This paper proposes a risk-aware rostering approach in maritime container terminals, i.e., it addresses the rostering problem of minimizing and balancing workers’ risk in such terminals. To this end, a mixed integer mathematical programming model incorporating workforce risks is proposed, considering constraints such as the satisfaction of the workforce demand to perform the terminal operations, the worker-task compatibility and restrictions on the sequence of tasks assigned to the same worker. The model has been successfully applied to plan workforce over a six months horizon in a real container terminal located in Northern Italy, the Southern European Container Hub (SECH) in Genoa. As the workforce demand in SECH terminal is available at most two weeks in advance, a rolling horizon planning approach is devised. Experimental tests on real data provided by SECH terminal over a six months planning horizon highlight the effectiveness of the approach - the maximum monthly risk for workers is reduced by 33.9% compared to the current planning – and suitability to other container terminal contexts. Moreover, the model is applicable to a broad range of port situations, and robust enough to need little adaptation

    Turin, Rome and Genoa: comparison of the level of maturity of three large Italian cities towards Mobility as a Service

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    Mobility as a Service (MaaS) is the new urban mobility paradigm which, through a digital platform, makes all types of public and private transport services available to users. This contributes to increasing sustainability in cities and the quality of citizens' mobility. However, several factors influence the success of MaaS implementation: openness and data sharing of transport operators; citizens' familiarity and willingness to pay; policy, regulation and legislation; transport services, and infrastructures. Many of these factors are strictly related to the features of the city where MaaS has to operate, and more specifically to its maturity (including multimodality, integration, flexibility, and user-oriented approach). To this end, target users and their willingness to pay for MaaS operations require a specific assessment. This paper compares three large Italian cities - Turin, Rome and Genoa, very different in terms of size, complexity, local transport policies and potential for MaaS application-, with the final goal of outlining common and specific drivers, barriers and requirements for the successful adoption of MaaS. The research findings can provide useful insights to urban mobility decision-makers to avoid the unsuccessful implementation of MaaS, especially when dealing with cities with conservative mobility policies, such as Rome, or where MaaS is a novelty

    Combining multiple trips in a port environment for empty movements minimization

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    Road transportation represents the most used transportation mode to cover short distances. However, structural lack of planning and optimization in road transportation creates negative effects both for companies and for the social community, such as environmental pollution, economic loss and road congestion. These effects are mainly due to the fact that a lack of planning can yield the necessity of a huge number of empty trips. Usually trucks that pick up or deliver a full container in a port must return back the empty container to the place where the trip started, so performing one leg of the total trip without payload. The aim of the present paper is to propose a mathematical approach for combining multiple trips in a port environment (specifically, import, export and inland trips) by considering the opportunity of carrying two 20 ft containers simultaneously on the same truck and by using the same load unit if possible. In this way, in the same route, more than two nodes can be visited with the same vehicle thus significantly reducing the number of total empty movements. Time windows constraints related to companies and terminal opening hours as well as to ship departures are considered in the problem formulation. Moreover driving hours restrictions and trips deadlines are taken into account, together with goods compatibility for matching different trips. An experimental campaign based on real data is discussed in the paper

    The Spread of MaaS Initiatives in Europe: The Leading Role of Public Governance Emerging from an Italian Regional Application

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    Mobility as a service (MaaS) is a promising lever to achieve a more sustainable, co-modal, and flexible urban system for daily mobility. MaaS is crucial to addressing the challenges imposed by hyper-urbanization, social changes, saturation of public soil with private motor vehicles, and local and global environmental issues. The aim of this paper is to analyse important characteristics of MaaS, namely public governance, regional scale, and high level of development. A total of 13 MaaS initiatives implemented in some European cities were compared using multi-criteria analysis. The results show that, although the MaaS implementation process is faster for private initiatives, public governance is shown to be the most appropriate entity to develop stable MaaS services, as it can enable the achievement of a higher level of integration, coupled with a high rate of service adoption, as well as reduce market entry barriers for service providers while also guaranteeing fair competition, and consequently fostering a higher level of service provided to users. The regional coverage of MaaS is crucial to ensure service provision to a wider population, living in both metropolitan and rural areas. These important features are included in the BIPforMaaS project run by the Italian region of Piedmont, described in detail in this paper

    Study of an emergency situation using 2D and 3D simulation models

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    Safety in motorway tunnels has become a critical issue in the last years, especially after the accident happened in 1999 inside the Mont Blanc tunnel, causing 39 deaths and several dozens of intoxications and wounded people. After this tragic event, the European Union imposed stricter regulations and procedures for emergency situations inside road tunnels longer than 1000 m. According to this situation, the authors propose the use of M&S (Modeling and Simulation) in order to manage a tunnel evacuation after a fire exploding in consequence to an accident, taking into account a series of significant factors like the road signs position (new criteria have been introduced with new regulation), but also human factors which significantly affect the procedure outcome. First a 2-D simulation model has been developed using Java™ Software, in which the user can analyze the behavior of the people escaping and the dynamics of the fire exploded and, consequently, assess the effectiveness of all the emergency procedures and infrastructures. In particular, regarding the state variables related to the human behavior, the model takes into account the main aspects of PECS (Physical Emotional Cognitive Social) reference models, in which physical, emotional, cognitive and social factors have to be studied. The model presented in this work is in fact quite similar to the one described by (Schmidt, 2000), called “Adam’s World” where Adam, a primitive man, lives in an environment having food sources where he can replenish his energy level, but also traps and danger points to be avoided in order not to consume his energy faster. The aim of the two models is the same: first of all preserve life and health, but the great difference between Schmidt’s model and the authors’ one is that in Adam’s World the social aspect is missing (Adam live alone in his world), while in the evacuation model social aspects can significantly affect the individual’s decisions. Upstream of the evacuation model, a weighted analysis needs to be considered, in fact the individual has to operate different choices considering several aspects, like health or goods preservation, familiar aspects, panic and so on. For this reason a suitable methodology has been detected: the Analytic Hierarchic Process (AHP), implemented by the American mathematician Thomas Saaty, which introduced this technique for Multi-Criteria Analysis. After the considerations on the individuals behavior based on the results of the analysis, the evacuation model and its results are described and analyzed in the following sections and, in the final part of the paper, a description of a 3-D tunnel model devoted to study in particular smoke dynamics is provided, thus it is possible to evaluate the impact of the smoke on the flow of the people escaping from the tunnel

    Using logistic redesigner (Lo.R.D.) software for designing and simulating a steel supply chain

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    This paper regards the analysis of the development of a logistics and transportation network concerning a steel plant. The main goal is to search for the best scenario that allows to supply the plant and to distribute all the finished products to final customers in the most efficient way. To this aim, a proper simulation model has been developed and implemented utilizing Logistics Re Designer (Lo. R. D.) software. More specifically, three different transportation networks have been created: two “single” modal choice scenarios - by road or by rail – and an “intermodal” one. Another system variable regards the production capacity of the steel plant: three different types of capacity have been considered; so in total nine scenarios have been taken into consideration. The results obtained indicate that the intermodal solution is the most suitable to be adopted both in terms of total time – and consequently costs - and resources required to perform all the necessary operations. Future research will focus on the improvement of the solution found and on the development of an economical analysis
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