225 research outputs found

    Retail Warehouse Loading Dock Coordination by Core-selecting Package Auctions

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    Congestions at loading docks can cause severe delays in logistics processes and cause increasing bottlenecks for truck routes. For warehouses, uncoordinated arrivals of trucks make appropriate staffing difficult and congestions can interfere with other processes at the facility. To mitigate congestions at loading docks, we propose package auctions to allocate time slots to trucks. \ \ The contribution of this research is the application of core-selecting package auctions to address the loading dock congestion problem. We propose a bidding language and a core-selecting package auction for this setting based on existing literature. Core-selecting payment rules can avoid drawbacks of the Vickrey–Clarke–Groves (VCG) mechanism with Clarke pivot rule, e.g., low perceived fairness of prices. \ \ We evaluate our proposal by means of simulation and assess (i) the potential for waiting time reduction compared to uncoordinated arrivals as well as sharing of historical waiting times, (ii) the empirical complexity of the computational problem for scenarios of varying complexity, and (iii) the relation of VCG and bidder-Pareto-optimal core payments. Our findings provide evidence that loading dock auctions can alleviate congestion substantially and that the core-pricing rule is well-suited to address the price fairness and low seller revenue problems in this setting

    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

    Hybrid modeling of collaborative freight transportation planning using agent-based simulation, auction-based mechanisms, and optimization

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    This is the author accepted manuscript. The final version is available from SAGE Publications via the DOI in this recordThe sharing economy is a peer-to-peer economic model characterized by people and organizations sharing resources. With the emergence of such economies, an increasing number of logistics providers seek to collaborate and derive benefit from the resultant economic efficiencies, sustainable operations, and network resilience. This study investigates the potential for collaborative planning enabled through a Physical Internet-enabled logistics system in an urban area that acts as a freight transport hub with several e-commerce warehouses. Our collaborative freight transportation planning approach is realized through a three-layer structured hybrid model that includes agent-based simulation, auction mechanism, and optimization. A multi-agent model simulates a complex transportation network, an auction mechanism facilitates allocating transport services to freight requests, and a simulation–optimization technique is used to analyze strategic transportation planning under different objectives. Furthermore, sensitivity analyses and Pareto efficiency experiments are conducted to draw insights regarding the effect of parameter settings and multi-objectives. The computational results demonstrate the efficacy of our developed model and solution approach, tested on a real urban freight transportation network in a major US city

    Proceedings of the International Symposium on Fresh Produce Supply Chain Management

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    Wal-Mart Stores, Inc. Strategic Corporate Research Report

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    [Excerpt] Wal-Mart Stores, Inc. (hereinafter Wal-Mart) is the second-largest company in the world. It has more annual revenue than the GDP of Switzerland. It sells more DVDs, magazines, books, CDs, dog food, diapers, bicycles, toys, toothpaste, jewelry, and groceries than any other retailer does worldwide. It is the largest retailer in the United States, Mexico, and Canada, the second-largest in the United Kingdom, and the third largest in Brazil, With its partners, it is the largest retailer in Central America. Wal-Mart is also the largest private employer in the United States, Mexico, and Canada, and it has 1.8 million employees around the globe. Wal-Mart is so huge that it effectively sets the terms for large swaths of the global economy, from retail wages to apparel prices to transoceanic shipping rates to the location of toy factories. Indeed, if there is one single aspect to understand about the company, it is the fact that Wal-Mart is transforming the relations of production in virtually every product category it sells, through its relationships with suppliers. But its influence goes far beyond the economy. It sets social policy by refusing to sell certain types of birth control. Its construction of supercenters molds the landscape, shapes traffic patterns, and alters the local commercial mix. The retail goliath shapes culture by selling the music of patriotic country singer Garth Brooks but not the critical (and hilarious) The Daily Show with Jon Stewart Presents America (the Book): A Citizen’s Guide to Democracy Inaction. It influences politics by donating millions to conservative politicians and think tanks. Wal-Mart is, in short, one of the most powerful entities in the world. Not surprisingly, Wal-Mart has developed a long list of critics, including unions, human rights organizations, religious groups, environmental activists, community organizations, small business groups, academics, children’s rights groups, and even institutional investors. These groups have exposed the company’s illegal union-busting tactics, its many violations of overtime laws, its abuse of child labor, its egregious healthcare policies, its super-exploitation of immigrant workers, its rampant gender discrimination, the horrific labor conditions at its suppliers’ factories, and its unlawful environmental degradation. They have also chronicled the deleterious effect Wal-Mart has on the public coffers and the quality of community life. New Wal-Mart stores and distribution centers often swallow up government subsidies and tax breaks, take public land, create more congestion, reduce overall wages, destroy retail variety, and increase public outlays for healthcare. To its critics, Wal-Mart represents the worst aspects of 21st-eentury capitalism. Wal-Mart usually counters any criticism with two words: low prices. It is a powerful mantra in a consumerist world. The company does make more products affordable to more people, and that is nothing to sneeze at when wages are stagnant, jobs insecure, pensions disappearing, and health coverage shrinking. With low prices, Wal-Mart helps working men and women get more from their meager paychecks, more necessities like bread, and more luxuries, like roses, too. It is a brilliant and incontrovertible argument, and Wal-Mart’s most ardent defenders take it even farther. They say its obsession with low prices makes the entire economy more efficient and more productive. Suppliers and competitors have to produce more and better products with the same resources, and that redounds to everyone. In the micro, it means falling prices and rising product quality. In the macro, it means economic growth, more jobs, and higher tax revenues. To its defenders, Wal-Mart represents the best aspects of 21st-century capitalism. Despite their radical opposition, critics and defenders of the world’s largest corporation agree on one thing: Wal-Mart represents 21st-century capitalism. It symbolizes a system of increasing market penetration and decreasing social regulation, where more and more aspects of life around the world are subject to economic competition. Wal-Mart’s success rests upon the ongoing destruction of social power in favor of corporate power. It takes advantage of the conditions of the neo-liberal world, from the availability of instant and inexpensive global communication to the continuing collapse of agricultural employment around the world to the rapid diffusion of technological innovation to the oversupply of subjugated migrant labor in nearly every country to the continued existence of undemocratic and corporate-dominated governments. For some, this is as it should be, all part of capitalism’s natural and ultimately benign development. For the rest of us, Wal-Mart is at the heart of what is wrong with the world

    Supply chain business modelling

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    The developed work is motivated by the hypothesis that the presented Supply Chain Business Model is a practical and comprehensive approach to support not only operational day-to-day business decisions, but most importantly strategic and long term decisions that may define the success and the longevity of a business. Conceptually, the Business Supply Chain Model developed in this thesis replicates the behaviour and decision making of the different agents in a supply chain, and an Optimisation Module determines the optimised parameters that maximise the overall business profit, whatever scenario it may be. In the optimisation module, a Genetic Algorithm was used to determine the best equation parameters for each individual agent that optimise the overall supply chain profit. Furthermore, several business case-scenarios are presented and the findings highlighted. These case-scenarios prove that: the HC model is robust when subjected to predictable or unpredictable causes of variability; the bullwhip effect can be reduced significantly by applying GA as the optimisation tool; the improvement of profits needs to be evaluated at a global scale, independently of the individual agents’ profit; impact of supply shortages in the SC ; retail expansion analysis; delivery patterns change impact in profitability; impact of sourcing decisions in the SC profitability; model suitability for seasonal vs. non-seasonal products. The SC Modelling framework generic and globalising approach means that is easily applied and transposed to any other business realities and it can be easily changed to reflect other SC scenarios. The costing model associated means that, at any point in the network, all costs and profits can be easily measured. For the first time the shelf-life of a product captured and losses of product due to BBE dates, quantified. In this model the optimisation methodology runs parallel to the developed simulation tool, so the optimisation should be only run for new scenarios

    Internet-of-things (IOT) - technologies enabling efficient inbound and outbound logistics in engineer-to-order (ETO) manufacturing companies

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    Confidential until 23. May 202

    Sustainable supply chains in the world of industry 4.0

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    Horizontal Cooperation in Transport and Logistics.

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    This thesis deals with horizontal cooperation in transport and logistics. It contains a comprehensive discussion of the available academic literature on this topic, many practical examples, and an empirical investigation of opportunities and impediments. Furthermore, three enabling concepts for horizontal cooperation in transport and logistics are developed. The analysis is practice oriented in the sense that most of the results are based on real-life datasets. In case studies conducted, the most important goal is to learn lessons that are also applicable to other cases or industries. By contrast, in chapters that have a more theoretical point of departure, efforts are made to draw conclusions that are directly applicable in practice. Many different research techniques are used in this thesis. They include case study analysis, surveys, exploratory factor analysis, regression, game theory, vehicle routing heuristics, and facility location heuristics.
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