4,343 research outputs found

    Multi-energy retail market simulation with autonomous intelligent agents

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    Tese de doutoramento. Engenharia Electrotécnica e de Computadores. 2005. Faculdade de Engenharia. Universidade do Port

    A Representation of Tactical and Strategic Precursors of Supply Network Resilience Using Simulation Based Experiments

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    Modern supply chains are becoming increasingly complex and are exposed to higher levels of risk. Globalization, market uncertainty, mass customization, technological and innovation forces, among other factors, make supply networks more susceptible to disruptions (both those that are man-made and/or ones associated with natural events) that leave suppliers unavailable, shut-down facilities and entail lost capacity. Whereas several models for disruption management exist, there is a need for operational representations of concepts such as resilience that expand the practitioners’ understanding of the behavior of their supply chains. These representations must include not only specific characteristics of the firm’s supply network but also its tactical and strategic decisions (such as sourcing and product design). Furthermore, the representations should capture the impact those characteristics have on the performance of the network facing disruptions, thus providing operations managers with insights on what tactical and strategic decisions are most suitable for their specific supply networks (and product types) in the event of a disruption. This research uses Agent-Based Modeling and Simulation (ABMS) and an experimental set-up to develop a representation of the relationships between tactical and strategic decisions and their impact on the performance of multi-echelon networks under supply uncertainty. Two main questions are answered: 1) How do different tactical and strategic decisions give rise to resilience in a multi-echelon system?, and 2) What is the nature of the interactions between those factors, the network’s structure and its performance in the event of a disruption? Product design was found to have the most significant impact on the reliability (Perfect Order Fulfillment) for products with high degrees of componentization when dual sourcing is the chosen strategy. However, when it comes to network responsiveness (Order Fulfillment Cycle Time), this effect was attenuated. Generally, it was found that the expected individual impact these factors have on the network performance is affected by the interactions between them

    STRATEGIC PRODUCT DESIGN DECISIONS FOR UNCERTAIN, CONVERGING AND SERVICE ORIENTED MARKETS

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    Market driven product design decisions are receiving increasing attention in the engineering design research literature. Econometric models and marketing research techniques are being integrated into engineering design in order to assist with profit maximizing product design decisions. This stream of research is referred to as "Design for Market Systems" (DMS). The existing DMS approaches fall short when the market environment is complex. The complexity can be incurred by the uncertain action-reactions of market players which impose unexpected market responses to a new design. The complexity can originate from the emergence of a niche product which creates a new product market by integrating the features of two or more existing products categories. The complexity can also arise when the designer is challenged to handle the couplings of outsourced subsystems from suppliers and explore the integration of the product with service providers. The objective of the thesis is to overcome such limitations and facilitate design decisions by modeling and interpreting the complex market environment. The research objective is achieved by three research thrusts. Thrust 1 examines the impact of action-reactions of market players on the long and short term design decisions for single category products using an agent based simulation approach. Thrust 2 concerns the design decisions for "convergence products". A convergence product physically integrates two or more existing product categories into a common product form. Convergence products make the consumer choice behavior and profit implications of design alternatives differ significantly from the situation where only a single product market is involved. Thrust 3 explores product design decisions while considering the connection to the upstream suppliers and downstream service providers. The connection is achieved by a quantitative understanding of interoperability of physical product modules as well as between a physical product and a service provider

    Simulating a physical internet enabled mobility web: the case of mass distribution in France

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    International audiencePhysical Internet (PI, π) is a novel concept aiming to render more economically, environmentally and socially efficient and sustainable the way physical objects are transported, handled, stored, realized, supplied and used throughout the world. It enables, among other webs, the Mobility Web which deals with moving physical objects within an interconnected set of unimodal and multimodal hubs, transits, ports, roads and ways. We want to develop and use holistic simulations to study and quantify the impact in terms of economical, environmental, and social efficiency and performance of evolving from the current system of freight transportation toward an open logistics web in France. This paper focuses on how the mobility web simulator supporting this study was designed and developed. The simulator produces large-scale simulations of mobility webs consisting of a large number of companies, sites and agents dealing with thousands of daily orders. It supports route and rail transportation modes, pallets and PI-containers for product shipping, different kinds of routing and shipping strategies, and various types of hubs

    Role-playing games as a mean to validate agent-based models: an application to stakeholder-driven urban freight transport policy-making

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    Abstract Agent-based models (ABMs) are widely used to replicate transport environments accounting for interaction among stakeholders. Validation of ABMs implies assessing the extent to which the model, from assumptions to results, is capable of approximating reality. To this end, different methods have been proposed, but yet no widely accepted procedure has emerged. This paper addresses this problem and suggests using a procedure based on role-playing games (RPGs). A first application is described with the intent of providing a preliminary contribution to validate an ABM trying to mimic stakeholders' interaction in a multi-level decision-making process in the context of urban freight transport policy-making. The aim is twofold: (1) understand if the structure of the model and the opinion dynamics envisioned are consistent with a real negotiation process, (2) verify if the results derived from the ABM effort are in line with those derived from a real-life experiment. Results of the first preliminary experiment show that the model seems capable of reproducing real-world processes and confirm that well-thought-out RPGs can contribute to validating ABMs

    Role-playing games as a mean to validate agent-based models : an application to stakeholder-driven urban freight transport policymaking

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    Agent-based models (ABMs) are widely used to replicate transport environments accounting for interaction among stakeholders. Validation of ABMs implies assessing the extent to which the model, from assumptions to results, is capable of approximating reality. To this end, different methods have been proposed, but yet no widely accepted procedure has emerged. This paper addresses this problem and suggests using a procedure based on role-playing games (RPGs). A first application is described with the intent of providing a preliminary contribution to validate an ABM trying to mimic stakeholders’ interaction in a multi-level decisionmaking process in the context of urban freight transport policy-making. The aim is twofold: (1) understand if the structure of the model and the opinion dynamics envisioned are consistent with a real negotiation process, (2) verify if the results derived from the ABM effort are in line with those derived from a real-life experiment. Results of the first preliminary experiment show that the model seems capable of reproducing real-world processes and confirm that well-thought-out RPGs can contribute to validating ABMs. Keywords: city logistics, stakeholder engagement, participatory simulation, model validation, discrete choice modelspublishedVersio

    Effects of a Trust Mechanism on Complex Adaptive Supply Networks: An Agent-Based Social Simulation Study

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    This paper models a supply network as a complex adaptive system (CAS), in which firms or agents interact with one another and adapt themselves. And it applies agent-based social simulation (ABSS), a research method of simulating social systems under the CAS paradigm, to observe emergent outcomes. The main purposes of this paper are to consider a social factor, trust, in modeling the agents\' behavioral decision-makings and, through the simulation studies, to examine the intermediate self-organizing processes and the resulting macro-level system behaviors. The simulations results reveal symmetrical trust levels between two trading agents, based on which the degree of trust relationship in each pair of trading agents as well as the resulting collaboration patterns in the entire supply network emerge. Also, it is shown that agents\' decision-making behavior based on the trust relationship can contribute to the reduction in the variability of inventory levels. This result can be explained by the fact that mutual trust relationship based on the past experiences of trading diminishes an agent\'s uncertainties about the trustworthiness of its trading partners and thereby tends to stabilize its inventory levels.Complex Adaptive System, Agent-Based Social Simulation, Supply Network, Trust

    INFORMATION TECHNOLOGY AND THE VERTICAL ORGANIZATION OF INDUSTRY

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    A model has been developed to study the interdependence between the choice of information technology and industry structure. Advances in information technology might provide incentives for a firm to specialize or focus on its core competence. However, the degree of specialization depends on the extent of industry-level specialization, which is, in turn, the result of the behavior of individual firms and their adoption of information technology favoring specialization. Emerging electronic markets and industries have been chosen as an application domain, as they would not exist without information technology.

    A review of methodologies to assess urban freight initiatives

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    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

    Exploring Blockchain Adoption Supply Chains: Opportunities and Challenges

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    Acquisition Management / Grant technical reportAcquisition Research Program Sponsored Report SeriesSponsored Acquisition Research & Technical ReportsIn modern supply chains, acquisition often occurs with the involvement of a network of organizations. The resilience, efficiency, and effectiveness of supply networks are crucial for the viability of acquisition. Disruptions in the supply chain require adequate communication infrastructure to ensure resilience. However, supply networks do not have a shared information technology infrastructure that ensures effective communication. Therefore decision-makers seek new methodologies for supply chain management resilience. Blockchain technology offers new decentralization and service delegation methods that can transform supply chains and result in a more flexible, efficient, and effective supply chain. This report presents a framework for the application of Blockchain technology in supply chain management to improve resilience. In the first part of this study, we discuss the limitations and challenges of the supply chain system that can be addressed by integrating Blockchain technology. In the second part, the report provides a comprehensive Blockchain-based supply chain network management framework. The application of the proposed framework is demonstrated using modeling and simulation. The differences in the simulation scenarios can provide guidance for decision-makers who consider using the developed framework during the acquisition process.Approved for public release; distribution is unlimited
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