18 research outputs found

    A multi-scale agent-based modelling framework for urban freight distribution

    Get PDF
    Comprehensive modelling of urban freight operations remains a challenge in transportation research. This is partly due to the diversity of commodities transported, shipment units, vehicle types used, stakeholders’ objectives (e.g. suppliers, carriers, receivers), and to the limited availability of data. Thus, existing modelling efforts require several assumptions yet have limited behavioral foundations and minimal interaction between agents. This paper proposes a new agent-based modelling framework, which considers the heterogeneity of urban freight agents and their interactions. Agents include establishments (suppliers, carriers, and receivers) and freight vehicle drivers. Agents’ decisions are structured in three temporal resolutions: strategic, tactical, and operational. A single set of agents is represented throughout all modelling levels ensuring a consistent and sequential flow of information. At the strategic level, establishments’ characteristics and strategic decisions are modelled. These include location choices, fleet constitution, annual production/consumption of commodities, and establishment-to-establishment commodity flows. At the tactical level, shipments are assigned to carriers, who in turn plan their operations in terms of vehicle-driver-route assignments. Finally, at the operational level, the interactions between daily operational demands and transportation network supply are simulated. The supply representation has two different resolution levels (micro or meso) allowing for either detailed or computational efficient simulation. The simulation platform is distinct from previous works, as it explicitly considers planning horizons, replicates agent decision makings/interactions and involves a structure that allows for the propagation of influences bottom-up (e.g., prior simulation travel times on future route choice). The paper describes the simulation platform, constituent models, and illustrates its capabilities using an application of the modelling framework to the city of Singapore. Keywords: freight transport; city logistics; commodity flow; freight tours; simulation; AB

    A viral system algorithm to optimize the car dispatching in elevator group control systems of tall buildings

    Get PDF
    Nowadays is very common the presence of tall buildings in the business centres of the main cities of the world. Such buildings require the installation of numerous lifts that are coordinated and managed under a unique control system. Population working in the buildings follows a similar traffic pattern generating situations of traffic congestion. The problem arises when a passenger makes a hall call wishing to travel to another floor of the building. The dispatching of the most suitable car is the optimization problem we are tackling in this paper. We develop a viral system algorithm which is based on a bio-inspired virus infection analogy to deal with it. The viral system algorithm is compared to genetic algorithms, and tabu search approaches that have proven efficiency in the vertical transportation literature. The experiments undertaken in tall buildings from 10 to 24 floors, and several car configurations from 2 to 6 cars, provide valuable results and show how viral system outperforms such soft computing algorithms.Plan Estatal de Investigación Científica y Técnica y de Innovación (España

    Urban Freight Transport Demand Modelling: a State of the Art

    Get PDF
    The paper provides a review of freight transport demand models for applications in urban and metropolitan areas. The perspective adopted is the short-term one of public decision-makers involved in transport planning and traffic management. The paper recalls the general methodology to be used for assessing the city logistics scenario and the features of models in relation to the planning horizons: strategic, tactical and operative. The focus is on the transport demand models able to support the assessment of short-term policies/measures. Several models and methods have been proposed. They usually refer to the multi-stage modelling approach and can be classified in terms of reference unit: truck/vehicle, commodity/quantity, delivery and mixed. The paper offers an analysis of pros and cons of each above classes of models. The research prospects are also identified

    A review of methodologies to assess urban freight initiatives

    Get PDF
    Only few urban freight initiatives are expanding their scale of application beyond the initial pilot experimentation. To overcome existing barriers to larger scale optimization of urban freight distribution activities, it is necessary to develop and test proper methodologies that assess all aspects relevant to this context. In this paper we propose a classification of existing assessment methodologies, in order to underline their advantages and disadvantages, along with possible research gaps and future trends. For this review we adopt a framework constructed on two dimensions of an assessment methodology, namely method used and scope. As for the method used, methodologies can be either quantitative, if they aim at simulating or evaluating the outcomes in terms of vehicle flows, pollutant emissions, or monetary outcomes, or qualitative, if they are directed towards elucidating the subjective assessment of stakeholders. Concerning the scope, existing methodologies can cover three main aspects of urban freight distribution systems, such as measures to be assessed, stakeholders and impact areas

    Survey Design to Unravel Freight Transportation Demand of Establishments in Cities

    Get PDF
    Freight transportation serves the vital role of fulfilling the goods demand of residents in cities, yet little is known about the mechanisms that generate freight movements and their impact on traffic. Even though technology may allow us to better trace real-time movements, establishment surveys are still important to collect data on strategic and tactical freight transportation decisions. Leveraging state-of-art knowledge, a survey was specifically designed to investigate freight travel demand. This paper shows the preparation, execution and data processing of a survey on establishments in Singapore. Analysis of the survey data allows us to explain variations in delivery, such as, the types of supplier, the size and frequency of goods deliveries, and the timing of deliveries

    Understanding and predicting trends in urban freight transport

    Get PDF
    Among different components of urban mobility, urban freight transport is usually considered as the least sustainable. Limited traffic infrastructures and increasing demands in dense urban regions lead to frequent delivery runs with smaller freight vehicles. This increases the traffic in urban areas and has negative impacts upon the quality of life in urban populations. Data driven optimizations are essential to better utilize existing urban transport infrastructures and to reduce the negative effects of freight deliveries for the cities. However, there is limited work and data driven research on urban delivery areas and freight transportation networks. In this paper, we collect and analyse data on urban freight deliveries and parking areas towards an optimized urban freight transportation system. Using a new check-in based mobile parking system for freight vehicles, we aim to understand and optimize freight distribution processes. We explore the relationship between areas' availability patterns and underlying traffic behaviour in order to understand the trends in urban freight transport. By applying the detected patterns we predict the availabilities of loading/unloading areas, and thus open up new possibilities for delivery route planning and better managing of freight transport infrastructures. © 2017 IEEE

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

    Get PDF
    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

    A new evaluation approach to City Logistics projects A business-oriented Agent-Based model

    Get PDF
    Supplying goods to urban areas is a fundamental economic process because the majority of the world population lives and buys goods in cities. Freight distribu-tion activities in urban areas account for roughly 40% of supply chain costs and 60% of supply chain CO2 emissions. Moreover, surging e-commerce trends shape the urban freight transportation arena, increasing its complexity and the pressure on private actors. Thus, urban freight transportation activities generate negative externalities, but are relevant to a great amount of enterprises that compose the economic and social fabric. In this context, City Logistics (CL) emerged as a comprehensive concept driv-ing solutions to reduce negative externalities while interfering as little as possible with private actors’ operations and profitability. CL scholars and practitioners are facing several issues arising from e-commerce and population growth. In particu-lar, logistics service providers are called to optimize their operations in order to increase the speed of delivery. At the same time however, CL is dealing with technological and systemic innovation that might enhance optimization capabili-ties and network usage. As a response to the changing environment and within the mandate of CL paradigm, local authorities and private actors have invested on a wide range of initiatives. The variety of approaches adopted and stakeholders involved, at multiple governmental levels, are responsible for a mixed landscape of CL experiences across different regional contexts. Furthermore, despite their relatively large dif-fusion, CL initiatives often fail in taking up after a first pilot implementation, unable to reach paying customers after public subsidies are removed. Therefore, un-derstanding the major business aspects that underline the reasons for adopting CL initiative by private stakeholders is key to a more long-term vision on CL implementation and assessment. Previous research has given little attention to understanding the commercial and business aspects of CL projects before actually designing and implementing them, even though CL scholars have ascertained that evaluation methodologies need to encompass all aspects relevant issues for CL schemes. Several methodol-ogies have been proposed since the inception of CL with the evaluation objective in mind. However, they fall short in different ways. For instance, qualitative methods adopt a short-term feasibility approach to CL evaluation, and the subjec-tive evaluation of quantitative outcomes may potentially influence the ranking between different alternatives. On the other hand, modelling techniques need high quality data to simulate traffic flows and consumers’ demand, but fail short to ad-dress other important decision-making factors related to the business model of stakeholders. Research opportunities therefore lie in mixing the advantages of quantitative and qualitative approaches to include stakeholders in quantitative ex-ante evaluation of CL projects. My thesis will try to answer to the following research questions. -Research question 1: What is the state-of-art of CL projects modelling and evaluation meth-ods/frameworks? -Research question 2: How can an integrated qualitative-quantitative framework for CL evaluation be conceived? -Research question 3: How can a new evaluation framework effectively integrate a business-oriented view of CL systems? The first objective of this thesis is to highlight advantages and disadvantages of assessment methodologies with respect to the integration of the business mo-tives of CL actors into non-project specific, a long-term view on CL project as-sessment. The second objective of this work is to define a theoretical framework for designing and assessing CL projects business models on a qualitative level. To this end, CL systems are here compared to business ecosystems, which are a network of interrelated business entities. In the framework, CL actors can play multi-ple roles, and their decisions are based on their objectives, information, and con-straints. The business model of a business entity within the system is the set of the roles it plays, the business and operative relationships formed with other business entities, and the monetary and intangible values exchanged through these relationships. New quantitative methods are needed for a more sound representation of the patterns emerging from the different behaviours of agents. Hence, the third objective is to build an agent-model proposal for modelling, simulating and ultimately evaluating CL projects business model. In agent-based modelling, each actor can be modelled as an agent possessing objectives and decision-making attributes. Agents act autonomously and their interactions are defined formally by means of ontologies and model narratives built as a representation of real-life system. Finally, an experiment design will be constructed to provide insights on an ex-isting case study related to the introduction of automated parcel locker station. Two CL ecosystem configurations are modelled together in order to simulate the decision to adopt a new logistics service by potential customers. Then, the effect of the decision regarding the allocation of marketing and R&D budget is also evaluated. From the simulation runs, it becomes clear that the outcome for each ecosystem configuration in terms of profits and customers is strongly influenced by the decisions taken within the other configuration. In summary, this thesis provides a first modelling and simulation tool for as-sessing the implications of business model decisions within specific CL business ecosystems. For instance, the strategic decision to adopt a service proposed by a CL company is associated with the evaluation of intangible benefits offered by such company. Moreover, the modelling tool highlights the links between such strategic decisions and the operative ones, such as vehicle routing or inventory policies. Therefore, it proves that qualitative approaches can be used to integrate all stakeholders, while quantitative modelling provide a simulation environment to test long-term effects of different scenarios. However, this study has some limita-tions. For instance, more strategic decisions should be included in the model to investigate endogeneity stemming from agents’ actions. Furthermore, the implica-tion on the business ecosystem of the value of information are not assessed. Finally, the scope of the computational experiment should be widened to include a per-formance evaluation phase, which would then lead to more decision-making by the agents. Further research is aimed at using the tools developed in the thesis to understand how to drive retailers to change their attitude towards CL by under-standing and designing value proposition that might appeal to them. Moreover, the implications of the entrance of new CL players one traditional ones’ business model need to be explored more deeply from the strategic perspective of power relations
    corecore