Cross-Docking: A Proven LTL Technique to Help Suppliers Minimize Products\u27 Unit Costs Delivered to the Final Customers

This study aims at proposing a decision-support tool to reduce the total supply chain costs (TSCC) consisting of two separate and independent objective functions including total transportation costs (TTC) and total cross-docking operating cost (TCDC). The full-truckload (FT) transportation mode is assumed to handle supplier→customer product transportation; otherwise, a cross-docking terminal as an intermediate transshipment node is hired to handle the less-than-truckload (LTL) product transportation between the suppliers and customers. TTC model helps minimize the total transportation costs by maximization of the number of FT transportation and reduction of the total number of LTL. TCDC model tries to minimize total operating costs within a cross-docking terminal. Both sub-objective functions are formulated as binary mathematical programming models. The first objective function is a binary-linear programming model, and the second one is a binary-quadratic assignment problem (QAP) model. QAP is an NP-hard problem, and therefore, besides a complement enumeration method using ILOG CPLEX software, the Tabu search (TS) algorithm with four diversification methods is employed to solve larger size problems. The efficiency of the model is examined from two perspectives by comparing the output of two scenarios including; i.e., 1) when cross-docking is included in the supply chain and 2) when it is excluded. The first perspective is to compare the two scenarios’ outcomes from the total supply chain costs standpoint, and the second perspective is the comparison of the scenarios’ outcomes from the total supply chain costs standpoint. By addressing a numerical example, the results confirm that the present of cross-docking within a supply chain can significantly reduce total supply chain costs and total transportation costs

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

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

Physical internet-enabled hyperconnected distribution assessment

L'Internet Physique (IP) est une initiative qui identifie plusieurs symptômes d'inefficacité et non-durabilité des systèmes logistiques et les traite en proposant un nouveau paradigme appelé logistique hyperconnectée. Semblable à l'Internet Digital, qui relie des milliers de réseaux d'ordinateurs personnels et locaux, IP permettra de relier les systèmes logistiques fragmentés actuels. Le but principal étant d'améliorer la performance des systèmes logistiques des points de vue économique, environnemental et social. Se concentrant spécifiquement sur les systèmes de distribution, cette thèse remet en question l'ordre de magnitude du gain de performances en exploitant la distribution hyperconnectée habilitée par IP. Elle concerne également la caractérisation de la planification de la distribution hyperconnectée. Pour répondre à la première question, une approche de la recherche exploratoire basée sur la modélisation de l'optimisation est appliquée, où les systèmes de distribution actuels et potentiels sont modélisés. Ensuite, un ensemble d'échantillons d'affaires réalistes sont créé, et leurs performances économique et environnementale sont évaluées en ciblant de multiples performances sociales. Un cadre conceptuel de planification, incluant la modélisation mathématique est proposé pour l’aide à la prise de décision dans des systèmes de distribution hyperconnectée. Partant des résultats obtenus par notre étude, nous avons démontré qu’un gain substantiel peut être obtenu en migrant vers la distribution hyperconnectée. Nous avons également démontré que l'ampleur du gain varie en fonction des caractéristiques des activités et des performances sociales ciblées. Puisque l'Internet physique est un sujet nouveau, le Chapitre 1 présente brièvement l’IP et hyper connectivité. Le Chapitre 2 discute les fondements, l'objectif et la méthodologie de la recherche. Les défis relevés au cours de cette recherche sont décrits et le type de contributions visés est mis en évidence. Le Chapitre 3 présente les modèles d'optimisation. Influencés par les caractéristiques des systèmes de distribution actuels et potentiels, trois modèles fondés sur le système de distribution sont développés. Chapitre 4 traite la caractérisation des échantillons d’affaires ainsi que la modélisation et le calibrage des paramètres employés dans les modèles. Les résultats de la recherche exploratoire sont présentés au Chapitre 5. Le Chapitre 6 décrit le cadre conceptuel de planification de la distribution hyperconnectée. Le chapitre 7 résume le contenu de la thèse et met en évidence les contributions principales. En outre, il identifie les limites de la recherche et les avenues potentielles de recherches futures.The Physical Internet (PI) is an initiative that identifies several symptoms of logistics systems unsustainability and inefficiency and tackles them by proposing a novel paradigm called Hyperconnected Logistics. Similar to the Digital Internet, which connects thousands of personal and local computer networks, PI will connect the fragmented logistics systems of today. The main purpose is to enhance the performance of logistics systems from economic, environmental and social perspectives. Focusing specifically on the distribution system, this thesis questions the order of magnitude of the performance gain by exploiting the PI-enabled hyperconnected distribution. It is also concerned by the characterization of the hyperconnected distribution planning. To address the first question, an exploratory research approach based on optimization modeling is applied; first, the current and prospective distribution systems are modeled. Then, a set of realistic business samples are created, and their economic and environmental performance by targeting multiple social performances are assessed. A conceptual planning framework is proposed to support the decision making in the hyperconnected distribution system. Based on the results obtained by our investigation, it can be argued that a substantial gain can be achieved by shifting toward Hyperconnected Distribution. It is also revealed that the magnitude of the gain varies by business characteristics and the targeted social performance. Since the Physical Internet is a novel topic, chapter 1 briefly introduces PI and Hyperconnected Logistics. Chapter 2 discusses the research foundations, goal and methodology. It also describes the challenges of conducting this research and highlights the type of contributions aimed for. Chapter 3 presents the optimization models including a core distribution network design modeling approach. Influenced by the characteristics of the current and prospective distribution systems, three distribution system-driven models are developed. Chapter 4 engages with the characterization of the business samples, the modeling and calibration of the parameter that are employed in the models. The exploratory investigation results are presented in Chapter 5. Chapter 6 describes the hyperconnected distribution planning framework. Chapter 7 summarizes the content of the thesis and highlights the main contributions. Moreover, it identifies the research limitations and potential future research avenues

Under-utilisation of road freight vehicle capacity: A case for eco-efficiency through collaboration

The road haulage sector experiences a considerable amount of inefficiency, characterised by sub-optimal utilisation of an individual vehicle’s cubic load fill and weight hauling capacity. This study firstly aims to understand why – despite its evident economic and environmental cost – this phenomenon has existed over the years. Next, an overview of initiatives and opportunities for improving freight vehicle capacity utilisation will be given. This paper by no means attempts to suggest that part-loaded or empty trucking can be fully eliminated. What is argued however is that there is theoretical scope for reducing the socio-environmental externalities of these activities while sustaining – if not increasing – the benefits that road haulage offers to the economy. Alongside direct mitigation of energy efficiency (by vehicle technology and/or modal shifts), maximizing existing vehicle capacity utilization must also form an integral part of efforts to green modern road freight logistics.It is suggested that horizontal collaboration and multi-actor co-loading of freight vehicles holds the greatest potential for improving vehicle fill rates. This requires little capital investment and would mean that the same degree of utility is delivered with fewer individual vehicles on the road. However, it is also argued that a collaborative road freight model may come in conflict with modern customer demands and production patterns, which typically involve rapid just-in-time deliveries of ever smaller consignments. Subsequently the widespread outsourcing of road freight operations to external third-party operators has not resulted in pronounced gains in vehicle capacity utilisation. It appears that a transport operator has very limited ability to better consolidate goods within its vehicles, unless its contractors offer an operational environment where this is possible. This paper suggests that a platform be established that will enable transport purchasers (contractors) to identify synergies in their logistical flows. This should help to move away from one-vehicle-to-one-customer arrangements, and develop an approach where a single moving vehicle’s available capacity is viewed as a service that is available for the benefit of several actors at the same time

Dynamic routing and service network design for less-than-truckload (LTL) motor carriers

This research tries to address the dynamic priority shipment routing problem and dynamic service network design problem for the less-than-truckload (LTL) carriers. First, described is a decision support tool to assist LTL managers in studying, analyzing and planning LTL operations so that scarce resources are used more effectively and efficiently. The decision support tool helps to understand the complicated interactions between the shipment route, closing rules, cost, and service level. Numerical experiments are done using the decision support tool to analyze the existing rules of LTL carriers and to understand their effect on the total cost of the system and the service level provided;Currently, LTL carriers route both regular and priority shipments through their service networks using some fixed route patterns known as load plans. In this research, an alternative routing strategy for routing priority shipments in LTL networks is proposed. This strategy exploits the stochasticity and dynamism embedded in the routing process and utilizes the real time information about terminals to determine the shipment routes adaptively. The research shows that this strategy can be formulated as the problem of finding a dynamic shortest path problem over a network with random arc costs. An efficient algorithm is developed that can solve this optimization problem in real-time. Numerical testing using real data sets suggests that the proposed strategy can improve the level of service for priority shipments;LTL carriers currently use ad hoc rules in deciding when there is enough capacity to close a trailer. In order to reduce the fixed and penalty costs incurred by the LTL carriers and to increase the service level provided by LTL carriers to customers, the decision should be optimized over time. In other words, the decision to dispatch a trailer should not only depend on the current shipment level, but should also vary dynamically based on time of day, day of the week, and seasonal effects. A dynamic control policy for dispatching a trailer over a single link is proposed in this research. This research provides an approach to estimate the shape of the recourse function. The dynamic control policy exploits the linearity of the recourse function estimated in solving the trailer dispatching problem efficiently. The algorithm is easy to implement and computationally fast and hence can be extended to solve large LTL networks. Experiments with the dynamic control policy show that the solutions obtained are very close to the optimal

Inter-firm collaboration in transportation

Dans la littérature académique et professionnelle relative au transport de marchandise, il y a longtemps que les méthodes de planification avancées ont été identifiées comme un moyen de dégager des économies grâce à une efficacité accrue des opérations de transport. Plus récemment, la collaboration interentreprises dans la planification du transport a été étudiée comme une source de gain supplémentaire en efficacité et, par conséquent, une opportunité pour dégager de nouvelles économies pour les collaborateurs. Cependant, la mise en œuvre d'une collaboration interentreprises en transports soulève un certain nombre d’enjeux. Cette thèse aborde trois thèmes centraux de la collaboration interentreprises et démontre les contributions via des études de cas dans l’industrie forestière et du meuble. Premièrement, les moyens technologiques pour soutenir une collaboration en planification du transport sont étudiés. Un système d’aide à la décision supportant la collaboration en transport forestier est présenté. Deuxièmement, le partage entre les collaborateurs du coût commun en transport est étudié. Une méthode de répartition du coût de transport tenant compte de l'impact - l’augmentation du coût de transport - des exigences inégales entre des collaborateurs est proposée. Troisièmement, la création de groupes collaboratifs - des coalitions - dans un ensemble de collaborateurs potentiel est étudiée. Un modèle réseau pour la formation d’une coalition selon les intérêts d’un sous-ensemble de collaborateurs adoptant ou pas un comportement opportuniste est détaillé. De plus, pour soutenir l'étude des thèmes précédents, la thèse comprend deux revues de la littérature. Premièrement, une revue sur les méthodes de planification et les systèmes d’aide à la décision en transport forestier est présenté. Deuxièmement, à travers la proposition d'un cadre pour créer et gérer une collaboration en transport et, plus généralement en logistique, une revue de travaux sur le transport et la logistique collaborative est offerte.In the academic and professional literature on freight transportation, computer-based planning methods have a long time ago been identified as a means to achieve cost reduction through enhanced transportation operations efficiency. More recently, inter-firm collaboration in transportation planning has been investigated as a means to provide further gains in efficiency and, in turn, to achieve additional cost reduction for the collaborators. However, implementation of inter-firm collaboration in transportation raises a number of issues. This thesis addresses three central themes in inter-firm collaboration and exemplifies the contributions in case studies involving collaboration in furniture and forest transportation. First, technological means to enable collaboration in transportation planning are studied. Embedding a computer-based planning method for truck routing, a decision support system enabling collaborative transportation is presented. Second, sharing the common transportation cost among collaborators is studied. A cost allocation method taking into account the impact – an increase of the transportation cost – of uneven requirements among collaborators is proposed. Third, building collaborating groups (i.e. coalitions) among a set of potential collaborators is studied. A network model for coalition formation by a subset of self-interested collaborators adopting or not an opportunistic behaviour is detailed. Moreover, to support the study of the aforementioned themes, the thesis includes two literature reviews. First, a survey on planning methods and decision support systems for vehicle routing problem in forest transportation is presented. Second, through the proposition of a framework for building and managing collaboration in transportation and, more generally in logistics, a survey of works on collaborative transportation and logistics is given