158 research outputs found

    Iterative Combinatorial Auction for Carrier Collaboration in Logistic Services

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    In collaborative logistics, multiple carriers form a network to share their transportation capacities. Collaboration among carriers results in improved resource utilization and, therefore, reduced costs. In this thesis, we propose an auction-based model for carrier collaboration in transportation services. The model achieves carrier collaboration through facilitating the negotiation among carriers over a group of shipping orders required by one or a group of shippers. The negotiation is conducted through a combinatorial iterative auction mechanism with the objective of minimizing the carriers’ overall costs. We first present a centralized carrier collaboration problem model in which a central entity has all required information to compute an optimal solution. We then consider a more realistic game theoretic setting where auction-based mechanism is applied to deal with self-interests of carriers. Compared with one-shot auctions, the proposed iterative bidding framework has the properties of reducing carriers’ information revelation and accommodating dynamic changes during the bidding process. Experimental results show that the procurement cost performance and the quality of solutions computed using the proposed iterative auction model is close to that of the optimal solutions

    Models for Reducing Deadheading through Carrier and Shipper Collaboration

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    The competitive nature in the trucking industry has forced trucking firms to develop innovative solutions to improve their operational efficiency and decrease marginal costs. There is also a great need to reduce deadheading miles of heavy trucks to help reduce the amount of air pollutants they emit. One way carriers and shippers are attempting to accomplish these goals is through various collaborative operational strategies. This work focuses on developing multiple collaboration frameworks and formulating optimization models for each framework that demonstrates the operations and reveals the potential cost savings of each framework.;The first collaboration framework focuses on how a medium level shipper or carrier can introduce collaboration in their operations by fulfilling a collaborative carrier\u27s or shipper\u27s delivery requests on its backhaul route. Two optimization models are developed to route the carrier of interest\u27s backhaul routes and select collaborative shipments to fulfill; one is formulated as an integer program and the other is formulated as a mixed integer program. Two solution methodologies, a greedy heuristic and tabu search, are used to solve the two problems, and numerical analysis is performed with a real world freight network. Numerical analysis on a real world freight network reveals that the percentage of cost savings for backhaul routes can be as high as 27%.;The second collaboration framework focuses on a group of shippers that collaborate their operations and form cycles between their long-haul shipping lanes. If the shippers provide the bundled lanes, as loops, to a common carrier they can realize cost savings from the carrier. The problem is formulated as a mixed integer program and forms least cost loops between the shipping lanes. A tabu search heuristic is used to solve the second collaboration framework and results using a real freight network reveal collaborative network costs savings between 7% to 12%. Three cost allocation mechanisms are proposed for the problem to distribute the costs to the shippers involved in the collaboration and computational results are provided for each of the allocation mechanisms

    An auction for collaborative vehicle routing: Models and algorithms

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    Increasing competition and expectations from customers pressures carriers to further improve efficiency. Forming collaborations is essential for carriers to reach their targeted efficiency levels. In this study, we investigate an auction mechanism to facilitate collaboration amongst carriers while maintaining autonomy for the individual carriers. Multiple auction implementations are evaluated. As the underlying decision problem (which is a traditional vehicle routing problem) is known to be NP-hard, this auction mechanism has an important inherent complexity. Therefore, we use fast and efficient algorithms for the vehicle routing problem to ensure that the auction can be used in operational decision making. Numerical results are presented, indicating that the auction achieves a savings potential better than the thus far reported approaches in the literature. Managerial insights are discussed, particularly related to the properties of the auction and value of the information

    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

    Collaborative urban transportation : Recent advances in theory and practice

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    We thank the Leibniz Association for sponsoring the Dagstuhl Seminar 16091, at which the work presented here was initiated. We also thank Leena Suhl for her comments on an early version of this work. Finally, we thank the anonymous reviewers for the constructive comments.Peer reviewedPostprin

    Operative Planning with Exchangeable and Mandatory Tasks : Applications to Lot Size Planning and Transportation Planning

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    Lot-sizing problems of manufacturers and transportation planning problems of forwarders are presented and analyzed in this thesis. These problems represent crucial planning tasks in supply chain management. Due to high fluctuations and competitive markets, companies within supply chains use internal and external resources for the fulfillment of tasks. The thesis claims to contribute to the following topics: (1) introducing mandatory tasks for the DULR, IOTPP, CTPP, and CIOTPP as well as (2) presenting computational studies that demonstrate how much the costs of companies increase due to mandatory tasks. Mandatory tasks are tasks, which have to be fulfilled by appointed resources due to contractual obligations. A lack of research is identified in terms of this topic. It is usually assumed that a task can be fulfilled by any internal or external resources. The thesis describes how these planning tasks with mandatory tasks can be solved by using operations research. Therefore, existing mathematical models and solution approaches have to be extended. The thesis focuses on the determination of the impact of mandatory tasks based on computational studies

    Agent-Based System Design for Service Process Scheduling: Challenges, Approaches and Opportunities

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    Compared with traditional manufacturing scheduling, service process scheduling poses additional challenges attributable to the significant customer involvement in service processes. In services, there are typically no inventoried products, which make the service provider's capacity more sensitive to dynamic changes. Service process scheduling objectives are also more complicated due to the consideration of customer preferences, customer waiting costs and human resource costs. After describing the Unified Services Theory and analysing its scheduling implications, this paper reviews the research literature on service process scheduling system design with a particular emphasis on agent-based approaches. Major issues in agent-based service process scheduling systems design are discussed and research opportunities are identified. The survey of the literature reveals that despite of many domain-specific designs in agent-based service process scheduling, there is a lack of general problem formulations, classifications, solution frameworks, and test beds. Constructing these general models for service process scheduling system design will facilitate the collaboration of researchers in this area and guide the effective development of integrated service process scheduling systems

    The bid construction problem for truckload transportation services procurement in combinatorial auctions : new formulations and solution methods

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    De nos jours, l'évolution du commerce électronique ainsi que des niveaux de la consommation requièrent des acteurs de la chaine logistique et en particulier les transporteurs de gérer efficacement leurs opérations. Afin de rester concurrentiels et maximiser leurs profits, ils doivent optimiser leurs opérations de transport. Dans cette thèse de doctorat, nous nous focalisons sur les enchères combinatoires en tant que mécanisme de négociation pour les marchés d'approvisionnement des services de transport routier par camions permettant à un expéditeur d'externaliser ses opérations de transport et aux transporteurs d'acquérir des contrats de transport. Les mises combinatoires permettent à un transporteur participant à l'enchère d'exprimer ses intérêts pour une combinaison de contrats mis à l'enchère dans une même mise. Si la mise gagne, tous les contrats qui la forment seront alloués au transporteur au tarif exigé. Les défis majeurs pour le transporteur sont de déterminer les contrats de transport sur lesquels miser, les regrouper dans plusieurs mises combinatoires, s'il y a lieu, et décider des prix à soumettre pour chaque mise générée. Ces défis décisionnels définissent le problème de construction de mises combinatoires (BCP pour Bid Construction Problem). Chaque transporteur doit résoudre le BCP tout en respectant ses engagements préexistants et ses capacités de transport et en tenant compte des offres des compétiteurs, ce qui rend le problème difficile à résoudre. Dans la pratique, la majorité des transporteurs se basent sur leur connaissance du marché et leur historique pour fixer leurs prix des mises. Dans la littérature, la majorité des travaux sur le BCP considèrent des modèles déterministes où les paramètres sont connus et se limitent à un contexte de flotte homogène. En plus, nous notons qu'un seul travail à considérer une variante stochastique du BCP. Dans cette thèse de doctorat, nous visons à faire avancer les connaissances dans ce domaine en introduisant de nouvelles formulations et méthodes de résolution pour le BCP Le premier chapitre de cette thèse introduit une nouvelle variante du BCP avec une flotte hétérogène. En partant d'une comparaison des similitudes et des différences entre le BCP et les problèmes classiques de de tournées de véhicules, nous proposons une nouvelle formulation basée sur les arcs avec de nouvelles contraintes de bris de symétrie pour accélérer la résolution. Ensuite, nous proposons une approche heuristique et une autre exacte pour résoudre ce problème. L'heuristique développée est une recherche adaptative à grands voisinages (ALNS pour Adaptive Large Neighborhood Search) et se base sur le principe de destruction puis réparation de la solution à l'aide d'opérateurs conçus spécifiquement pour le BCP traité. La méthode exacte utilise la meilleure solution heuristique pour résoudre notre modèle mathématique avec le solveur CPLEX. Les résultats obtenus montrent la pertinence de nos méthodes en termes de qualités des solutions et des temps de calculs et ce pour des instances de grande taille. Dans le deuxième chapitre, nous nous attaquons à un cas particulier du BCP où le transporteur n'a pas d'engagements existants et vise à déterminer un ensemble de contrats mis à l'enchère profitables à miser dessus. Cette problématique correspond à un problème de tournées de véhicules avec profits (TOP pour Team Orienteering Problem). Nous proposons pour le TOP une heuristique ALNS hybride avec de nouveaux opérateurs ainsi que de nouvelles fonctionnalités tenant compte de la nature du problème. Ensuite, nous comparons les performances de notre méthode avec toutes les méthodes déjà publiées dans la littérature traitant du TOP. Les résultats montrent que notre méthode surpasse généralement toutes les approches existantes en termes de qualité des solutions et/ou temps de calculs quand elle est testée sur toutes les instances de la littérature. Notre méthode améliore la solution d'une instance de grande taille, ce qui surligne sa performance. Dans le troisième chapitre, nous nous focalisons sur l'incertitude associée aux prix de cessions des contrats mis à l'enchère et sur les offres des transporteurs concurrents. Il n'existe qu'un seul article qui traite de l'incertitude dans le BCP cependant il ne permet pas de générer des mises multiples. Ainsi, nous proposons une nouvelle formulation pour le BCP avec des prix stochastiques permettant de générer des mises combinatoires et disjointes. Nous présentons deux méthodes pour résoudre ce problème. La première méthode est hybride et à deux étapes. Dans un premier temps, elle résout un problème de sélection pour déterminer un ensemble de contrats profitables. Dans un second temps, elle résout simultanément un problème de sélection de contrats et de détermination de prix des mises (CSPP pour Contracts Selection and Pricing Problem) en ne considérant que les contrats sélectionnés dans la première étape. Notre méthode exacte résout, avec l'algorithme de branch-and-cut, le CSPP sans présélectionner des contrats. Les résultats expérimentaux et de simulations que nous rapportons soulignent la performance de nos deux méthodes et évaluent l'impact de certains paramètres sur le profit réel du transporteur. Dans le quatrième chapitre, nous nous focalisons sur l'incertitude liée au succès des mises et à la non-matérialisation des contrats. Généralement, le transporteur souhaite avoir la garantie que si certaines des mises ne sont pas gagnées ou un contrat ne se matérialise pas, il n'encourra pas de perte en servant le sous-ensemble de contrats gagnés. Dans cette recherche, nous adressons le BCP avec prix stochastiques et développons une méthode exacte qui garantit un profit non négatif pour le transporteur peu importe le résultat des enchères. Nos simulations des solutions optimales démontrent, qu'en moyenne, notre approche permet au transporteur d'augmenter son profit en plus de garantir qu'il reste non-négatif peu importe les mises gagnées ou la matérialisation des contrats suivant l'enchère.Nowadays, the evolution of e-commerce and consumption levels require supply chain actors, in particular carriers, to efficiently manage their operations. In order to remain competitive and to maximize their profits, they must optimize their transport operations. In this doctoral thesis, we focus on Combinatorial Auctions (CA) as a negotiation mechanism for truckload (TL) transportation services procurement allowing a shipper to outsource its transportation operations and for a carrier to serve new transportation contracts. Combinatorial bids offer a carrier the possibility to express his valuation for a combination of contracts simultaneously. If the bid is successful, all the contracts forming it will be allocated to the carrier at the submitted price. The major challenges for a carrier are to select the transportation contracts to bid on, formulate combinatorial bids and associated prices. These decision-making challenges define the Bid Construction Problem (BCP). Each carrier must solve a BCP while respecting its pre-existing commitments and transportation capacity and considering unknown competitors' offers, which makes the problem difficult to solve. In practice, the majority of carriers rely on their historical data and market knowledge to set their prices. In the literature, the majority of works on the BCP propose deterministic models with known parameters and are limited to the problem with a homogeneous fleet. In addition, we found a single work addressing a stochastic BCP. In this thesis, we aim to advance knowledge in this field by introducing new formulations and solution methods for the BCP. The first chapter of this thesis introduces the BCP with a heterogeneous fleet. Starting from a comparison between the BCP and classical Vehicle Routing Problems (VRPs), we propose a new arc-based formulation with new symmetry-breaking constraints for the BCP. Next, we propose exact and heuristic approaches to solve this problem. Our Adaptive Large Neighborhood Search (ALNS) heuristic is based on a destroy-repair principle using operators designed for this problem. Our exact method starts from the heuristic solution and solves our mathematical model with CPLEX. The results we obtained revealed the relevance of our methods in terms of solutions quality and computational times for large instances with up to 500 contracts and 50 vehicles. In the second chapter, we tackle a particular case of the BCP where the carrier has no pre-existing commitments and aims to select a set of profitable auctioned contracts to bid on. This problem corresponds to a Team Orienteering Problem (TOP). We propose a hybrid ALNS heuristic for the TOP with new operators as well as new features taking into account the nature of the problem. Then, we compare the performance of our algorithm against the best solutions from the literature. The results show that our method generally outperforms all the existing ones in terms of solutions quality and/or computational times on benchmark instances. Our method improves one large instance solution, which highlights its performance. In the third chapter, we focus on the uncertainty associated with the auctioned contracts clearing prices and competing carriers offers. Only one article dealing with uncertainty in the BCP existed but it does not allow to generate multiple bids. Thus, we propose a new formulation for the BCP with stochastic prices allowing to generate non-overlapping combinatorial bids. We present two methods to solve this problem. The first one is a two-step hybrid heuristic. First, it solves a Contracts Selection Problem to determine a set of profitable contracts to bid on. Secondly, it simultaneously solves a Contracts Selection and Pricing Problem (CSPP) by considering only the set of auctioned contracts selected in the first stage. Our exact method solves a CSPP by branch-and-cut without pre-selecting contracts. The experimental and simulation results underline the performance of our two methods and evaluate the impact of certain parameters on the carrier's real profit. In the fourth chapter, we focus on the uncertainty associated with bids success and contracts non-materialization. Generally, the carrier seeks to be assured that if some of the submitted bids are not won or a contract does not materialize, it will not incur a loss by serving the remaining contracts. In this research, we address the BCP with stochastic prices and develop an exact method that ensures a non-negative profit for the carrier regardless of the auction outcomes and contracts materialization. Our simulations of the optimal solutions show that, on average, our approach increases the carrier's profit in addition to guaranteeing its non-negativity regardless of the bids won or the contracts materialization
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