1,426 research outputs found

    Multi-objective Model on Connection Time Optimization in Sea-rail Intermodal Transport

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    Container sea-rail intermodal transport operation needs to consider some special demands both in volume and time connection. That means container sea-rail intermodal transport is a type of demand responsive transport between railroad trains and marine ships, vice versa. It needs to operate container trains according to the demands of ships in OD, volume, as well as the arrival and departure time. Basing on this responsive demand characteristic of sea-rail intermodal transport, the paper establishes a multi-objective optimal model for its connection time, aiming for maximizing the profits of carriers and minimizing the total transport costs of shippers, as well as minimizing the connection time between container trains and ships to optimizing the intermodal transport system. Modified genetic algorithm is adopted. The calculation results demonstrate that the model could be used to solve the connection problem of container sea-rail intermodal transport involved with volume and time connections

    Development of transportation and supply chain problems with the combination of agent-based simulation and network optimization

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    Demand drives a different range of supply chain and logistics location decisions, and agent-based modeling (ABM) introduces innovative solutions to address supply chain and logistics problems. This dissertation focuses on an agent-based and network optimization approach to resolve those problems and features three research projects that cover prevalent supply chain management and logistics problems. The first case study evaluates demographic densities in Norway, Finland, and Sweden, and covers how distribution center (DC) locations can be established using a minimizing trip distance approach. Furthermore, traveling time maps are developed for each scenario. In addition, the Nordic area consisting of those three countries is analyzed and five DC location optimization results are presented. The second case study introduces transportation cost modelling in the process of collecting tree logs from several districts and transporting them to the nearest collection point. This research project presents agent-based modelling (ABM) that incorporates comprehensively the key elements of the pick-up and delivery supply chain model and designs the components as autonomous agents communicating with each other. The modelling merges various components such as GIS routing, potential facility locations, random tree log pickup locations, fleet sizing, trip distance, and truck and train transportation. The entire pick-up and delivery operation are modeled by ABM and modeling outcomes are provided by time series charts such as the number of trucks in use, facilities inventory and travel distance. In addition, various scenarios of simulation based on potential facility locations and truck numbers are evaluated and the optimal facility location and fleet size are identified. In the third case study, an agent-based modeling strategy is used to address the problem of vehicle scheduling and fleet optimization. The solution method is employed to data from a real-world organization, and a set of key performance indicators are created to assess the resolution's effectiveness. The ABM method, contrary to other modeling approaches, is a fully customized method that can incorporate extensively various processes and elements. ABM applying the autonomous agent concept can integrate various components that exist in the complex supply chain and create a similar system to assess the supply chain efficiency.Tuotteiden kysyntä ohjaa erilaisia toimitusketju- ja logistiikkasijaintipäätöksiä, ja agenttipohjainen mallinnusmenetelmä (ABM) tuo innovatiivisia ratkaisuja toimitusketjun ja logistiikan ongelmien ratkaisemiseen. Tämä väitöskirja keskittyy agenttipohjaiseen mallinnusmenetelmään ja verkon optimointiin tällaisten ongelmien ratkaisemiseksi, ja sisältää kolme tapaustutkimusta, jotka voidaan luokitella kuuluvan yleisiin toimitusketjun hallinta- ja logistiikkaongelmiin. Ensimmäinen tapaustutkimus esittelee kuinka käyttämällä väestötiheyksiä Norjassa, Suomessa ja Ruotsissa voidaan määrittää strategioita jakelukeskusten (DC) sijaintiin käyttämällä matkan etäisyyden minimoimista. Kullekin skenaariolle kehitetään matka-aikakartat. Lisäksi analysoidaan näistä kolmesta maasta koostuvaa pohjoismaista aluetta ja esitetään viisi mahdollista sijaintia optimointituloksena. Toinen tapaustutkimus esittelee kuljetuskustannusmallintamisen prosessissa, jossa puutavaraa kerätään useilta alueilta ja kuljetetaan lähimpään keräyspisteeseen. Tämä tutkimusprojekti esittelee agenttipohjaista mallinnusta (ABM), joka yhdistää kattavasti noudon ja toimituksen toimitusketjumallin keskeiset elementit ja suunnittelee komponentit keskenään kommunikoiviksi autonomisiksi agenteiksi. Mallinnuksessa yhdistetään erilaisia komponentteja, kuten GIS-reititys, mahdolliset tilojen sijainnit, satunnaiset puunhakupaikat, kaluston mitoitus, matkan pituus sekä monimuotokuljetukset. ABM:n avulla mallinnetaan noutojen ja toimituksien koko ketju ja tuloksena saadaan aikasarjoja kuvaamaan käytössä olevat kuorma-autot, sekä varastomäärät ja ajetut matkat. Lisäksi arvioidaan erilaisia simuloinnin skenaarioita mahdollisten laitosten sijainnista ja kuorma-autojen lukumäärästä sekä tunnistetaan optimaalinen toimipisteen sijainti ja tarvittava autojen määrä. Kolmannessa tapaustutkimuksessa agenttipohjaista mallinnusstrategiaa käytetään ratkaisemaan ajoneuvojen aikataulujen ja kaluston optimoinnin ongelma. Ratkaisumenetelmää käytetään dataan, joka on peräisin todellisesta organisaatiosta, ja ratkaisun tehokkuuden arvioimiseksi luodaan lukuisia keskeisiä suorituskykyindikaattoreita. ABM-menetelmä, toisin kuin monet muut mallintamismenetelmät, on täysin räätälöitävissä oleva menetelmä, joka voi sisältää laajasti erilaisia prosesseja ja elementtejä. Autonomisia agentteja soveltava ABM voi integroida erilaisia komponentteja, jotka ovat olemassa monimutkaisessa toimitusketjussa ja luoda vastaavan järjestelmän toimitusketjun tehokkuuden arvioimiseksi yksityiskohtaisesti.fi=vertaisarvioitu|en=peerReviewed

    Simulation and optimization of a multi-agent system on physical internet enabled interconnected urban logistics.

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    An urban logistics system is composed of multiple agents, e.g., shippers, carriers, and distribution centers, etc., and multi-modal networks. The structure of Physical Internet (PI) transportation network is different from current logistics practices, and simulation can effectively model a series of PI-approach scenarios. In addition to the baseline model, three more scenarios are enacted based on different characteristics: shared trucks, shared hubs, and shared flows with other less-than-truckload shipments passing through the urban area. Five performance measures, i.e., truck distance per container, mean truck time per container, lead time, CO2 emissions, and transport mean fill rate, are included in the proposed procedures using real data in an urban logistics case. The results show that PI enables a significant improvement of urban transportation efficiency and sustainability. Specifically, truck time per container reduces 26 percent from that of the Private Direct scenario. A 42 percent reduction of CO2 emissions is made from the current logistics practice. The fill rate of truckload is increased by almost 33 percent, whereas the relevant longer distance per container and the lead time has been increased by an acceptable range. Next, the dissertation applies an auction mechanism in the PI network. Within the auction-based transportation planning approach, a model is developed to match the requests and the transport services in transport marketplaces and maximize the carriers’ revenue. In such transportation planning under the protocol of PI, it is a critical system design problem for decision makers to understand how various parameters through interactions affect this multi-agent system. This study provides a comprehensive three-layer structure model, i.e. agent-based simulation, auction mechanism, and optimization via simulation. In term of simulation, a multi-agent model simulates a complex PI transportation network in the context of sharing economy. Then, an auction mechanism structure is developed to demonstrate a transport selection scheme. With regard of an optimization via simulation approach and sensitivity analysis, it has been provided with insights on effects of combination of decision variables (i.e. truck number and truck capacity) and parameters settings, where results can be drawn by using a case study in an urban freight transportation network. In the end, conclusions and discussions of the studies have been summarized. Additionally, some relevant areas are required for further elaborate research, e.g., operational research on airport gate assignment problems and the simulation modelling of air cargo transportation networks. Due to the complexity of integration with models, I relegate those for future independent research

    Three essays on urban freight transport: models and tools for effective city logistics projects

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    The main purpose of these three years of research, summarized in this thesis, was to investigate the obstacles to the development of the city logistics initiatives by seeking solutions to overcome them through model and framework coming from management and transportation engineering. In particular, following a first analysis of a collection of European projects and a systematic analysis of scientific literature, three main gaps in city logistics have been identified: the lack of the stakeholders’ involvement, the need for data sharing platforms to overcome the current lack of data and the need to define city logistics solutions within the urban ecosystem, making consistent design choices coherently with what is already existing in terms of infrastructures, rules and stakeholders in the context. From these three gaps, three main research questions have arisen: (RQ1) Is it possible to support stakeholders in analysing CL solutions fitting their necessities applying some already existing and consolidate decision-making methods? (RQ2) Is it possible to define a database platform in which it is possible to collect, consult and update as many existing data as possible regarding urban freight transport? (RQ3) How is it possible to optimize city logistics infrastructures in a harmonious and coherent way with respect to the entire city logistics ecosystem? To answers to the research questions, a collection of articles is illustrated in this thesis work. From time to time different methodologies are used and illustrated, derived from the field of management and transport engineering, these different methodologies, such as the Systematic Literature Review, the House of Quality, a framework for building a data sharing platform, the city logistics Ecosystem and a decision-making support model (based on both a covering model and a Monte Carlo simulation) are described in detail in the various chapters of the thesis. In this dissertation work for the first time, the main obstacles to the development of city logistics initiatives, that are the lack of involvement of stakeholders, the lack of data, and the lack of an ecosystem vision of urban transport, have been identified and addressed at the same time. Even if literature sometimes offers some possible solutions to these gaps, few are simple to understand for those who work in the urban freight transport industry, easy to apply and replicable. Both in identifying the gap and in seeking solutions, the solutions showed in this thesis sought to address to those who work in the industry, mainly carriers, retailers, shop owners and public administration representatives, trying to combine scientific research with the search for solutions that can be implemented in practice as requested by such a practical research topic. For this reason, each proposed solution and methodology in this thesis has been implemented and experimented using as a case study the city of Bergamo (and testing its replicability in other European cities such as Saint-Etienne, Luxemburg and Amsterdam). In particular, the initial experience in the “Bergamo Logistica” project, part of the Bergamo 2.035 smart city research program, gave me the opportunity to understand the main critical issues found by the main actors who work in this field (i.e., carriers, couriers, retailers and institutions), to confirm some evidences that I found in the theory (i.e., main research gaps which originates the research questions) and to search for solutions that could both solve research gaps and optimize the daily logistics activities of the operators.The main purpose of these three years of research, summarized in this thesis, was to investigate the obstacles to the development of the city logistics initiatives by seeking solutions to overcome them through model and framework coming from management and transportation engineering. In particular, following a first analysis of a collection of European projects and a systematic analysis of scientific literature, three main gaps in city logistics have been identified: the lack of the stakeholders’ involvement, the need for data sharing platforms to overcome the current lack of data and the need to define city logistics solutions within the urban ecosystem, making consistent design choices coherently with what is already existing in terms of infrastructures, rules and stakeholders in the context. From these three gaps, three main research questions have arisen: (RQ1) Is it possible to support stakeholders in analysing CL solutions fitting their necessities applying some already existing and consolidate decision-making methods? (RQ2) Is it possible to define a database platform in which it is possible to collect, consult and update as many existing data as possible regarding urban freight transport? (RQ3) How is it possible to optimize city logistics infrastructures in a harmonious and coherent way with respect to the entire city logistics ecosystem? To answers to the research questions, a collection of articles is illustrated in this thesis work. From time to time different methodologies are used and illustrated, derived from the field of management and transport engineering, these different methodologies, such as the Systematic Literature Review, the House of Quality, a framework for building a data sharing platform, the city logistics Ecosystem and a decision-making support model (based on both a covering model and a Monte Carlo simulation) are described in detail in the various chapters of the thesis. In this dissertation work for the first time, the main obstacles to the development of city logistics initiatives, that are the lack of involvement of stakeholders, the lack of data, and the lack of an ecosystem vision of urban transport, have been identified and addressed at the same time. Even if literature sometimes offers some possible solutions to these gaps, few are simple to understand for those who work in the urban freight transport industry, easy to apply and replicable. Both in identifying the gap and in seeking solutions, the solutions showed in this thesis sought to address to those who work in the industry, mainly carriers, retailers, shop owners and public administration representatives, trying to combine scientific research with the search for solutions that can be implemented in practice as requested by such a practical research topic. For this reason, each proposed solution and methodology in this thesis has been implemented and experimented using as a case study the city of Bergamo (and testing its replicability in other European cities such as Saint-Etienne, Luxemburg and Amsterdam). In particular, the initial experience in the “Bergamo Logistica” project, part of the Bergamo 2.035 smart city research program, gave me the opportunity to understand the main critical issues found by the main actors who work in this field (i.e., carriers, couriers, retailers and institutions), to confirm some evidences that I found in the theory (i.e., main research gaps which originates the research questions) and to search for solutions that could both solve research gaps and optimize the daily logistics activities of the operators

    Combining Operative Train Simulation with Logistics Simulation in SUMO

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    Rail freight logistics is usually planned and analyzed using a macroscopic aggregated view on railway networks and train operations. As a result, disjoint tools have developed for simulating train operations which requires a detailed representation of track assets as well as the signaling architecture and supply chain networks in logistics analyzing the flow of goods where mode-specific capacity and traffic situations are incorporated in an aggregated manner. However, integrating the two areas could help evaluating railway-specific operative implications (such as conflicts and consequent delays) on the level of transport chains and thus single transport units instead of trains or network areas. The simulation tool SUMO is identified to meet criteria from both disciplines. It is shown how a respective methodology can be realized in SUMO to create such a simulation model. A use case of northwestern Germany shows by the means of exemplary container trajectories that the two simulative approaches can be merged

    Understanding Urban Mobility and Pedestrian Movement

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    Urban environments continue to expand and mutate, both in terms of size of urban area and number of people commuting daily as well as the number of options for personal mobility. City layouts and infrastructure also change constantly, subject to both short-term and long-term imperatives. Transportation networks have attracted particular attention in recent years, due to efforts to incorporate “green” options, enabling positive lifestyle choices such as walking or cycling commutes. In this chapter we explore the pedestrian viewpoint, aids to familiarity with and ease of navigation in the urban environment, and the impact of novel modes of individual transport (as options such as smart urban bicycles and electric scooters increasingly become the norm). We discuss principal factors influencing rapid transit to daily and leisure destinations, such as schools, offices, parks, and entertainment venues, but also those which facilitate rapid evacuation and movement of large crowds from these locations, characterized by high occupation density or throughput. The focus of the chapter is on understanding and representing pedestrian behavior through the agent-based modeling paradigm, allowing both large numbers of individual actions with active awareness of the environment to be simulated and pedestrian group movements to be modeled on real urban networks, together with congestion and evacuation pattern visualization

    On the spatial feasibility of crowdshipping services in university communities

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    Abstract Crowdshipping, i.e. delivering goods via the crowd, aims at combining passenger with freight trips. This concept is particularly useful, especially in urban contexts, since it allows using the spare capacity of vehicles and reducing the negative impacts of urban freight transport. While attractive in principle, a crowdshipping service needs to be appropriately conceived to be effective. In this respect, matching passenger with freight transport demand is one of the main issues to consider. Besides, it is important to promote a sustainable crowdshipping, i.e. perfomed via sustainable transport modes. This paper presents a GIS-based approach to evaluate the spatial feasibility of crowdshipping services using public transport or active modes in the context of a University community. The case study analyzed focuses on e-commerce deliveries and takes into account a campus with venues located in different zones in the city of Catania (Italy). The methodology is designed according to spatial considerations related to the proximity of delivery points and home addresses, students' flows between origins and destinations and main mode of transport used. Results are useful to design the service in a well-established community, which could be considered more inclined to be involved

    Research Trends of Inland Terminals: A Literature Review

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    Inland terminals are becoming an increasingly important factor for disburdening port storage capacities and the expansion of the port gravitational areas. The above defines inland terminals as facilities with prolonged activities of seaports, or an integral part of the port. Due to increased interest in the development of inland terminals, the literature in the field of inland terminals since the beginning of its research (1980) to the latest research in 2015 has been analysedand revised. The review will summarize the literature related to development, classification, technological processes and location of inland terminals. In the end, the paper identifies a new proposition for further research based on the current trends and developments in inland terminals as an important factor of intermodal transport.</p

    Evaluating the effects of road hump on speed and noise level at a university setting

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    This study is carried out to determine the effectivness of road humps to reduce the traffic speed and traffic noise in institutional area. The difference in hump profiles in terms of height, width and length are the main factors in determing the effectiveness of road humps. The difference in the profiles of the road hump will cause changing driver behaviour of the users especially when approaching the road hump. The road humps with different design profiles are selected to measure the speed and noise level of the vehicles at, before and after each of the selected road humps. Radar speed gun and noise level meters are used to measure speed and noise level of the vehicles at each of designated points along the major circular road in IIUM. The changes in speed and noise level at different selected points at each of the different profiles of the road humps are the expected findings of this study
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