Teodor Gabriel Crainic

Planning models for freight transportation

Abstract The objective of this paper is to identify some of the main issues in freight transportation planning and operations, and to present appropriate Operations Research models and methods, as well as computer-based planning tools. The presentation is organized according to the three classical decision-making levels: strategic, tactic, operational. For each case, the problem and main issues are described, followed by a brief literature review and significant methodological and instrumental developments. We conclude with a few development perspectives.

Fleet management and logistics

Preface. Introduction T.G. Crainic, G. Laporte. 1. Exact Solution of the Vehicle Routing Problem P. Toth, D. Vigo. 2. Metaheuristics in Vehicle Routing B.L. Golden, et al. 3. A Unified Framework for Deterministic Time Constrained Vehicle Routing and Crew Scheduling Problems G. Desaulniers, et al. 4. The Inventory Routing Problem A. Campbell, et al. 5. Dynamic Vehicle Routing and Dispatching M. Gendreau, J.-Y. Potvin. 6. On Languages for Dynamic Resource Scheduling Problems W.B. Powell. 7. Solving Stochastic Routing Problems G. Laporte, F.V. Louveaux. 8. Crew Scheduling in Air Transportation G. Desaulniers, et al. 9. Path, Tree and Cycle Location M. Labbe, et al. 10. Parallel Metaheuristics T.G. Crainic, M. Toulouse.

SERVICE NETWORK DESIGN IN FREIGHT TRANSPORTATION

Abstract Tactical planning of operations is comprised of a set of interrelated decisions that aim to ensure an optimal allocation and utilization of resources to achieve the economic and customer service goals of the company. Tactical planning is particularly vital for intercity freight carriers that make intensive use of consolidation operations. Railways and less-than-truckload motor carriers are typical examples of such systems. Service Network Design is increasingly used to designate the main tactical issues for this type of carriers: selection and scheduling of services, specification of terminal operations, routing of freight. The corresponding models usually take the form of network design formulations that are difficult to solve, except in the simplest of cases. The paper presents a state-of-the-art review of service network design modelling efforts and mathematical programming developments for network design. A new classification of service network design problems and formulations is also introduced.

Dynamic and stochastic models for the allocation of empty containers

The empty container allocation problem occurs in the context of the management of the land distribution and transportation operations of international maritime shipping companies. It involves dispatching empty containers of various types in response to requests by export customers and repositioning other containers to storage depots or ports in anticipation of future demands. We describe the problem and identify its basic structure and main characteristics. We then introduce two dynamic deterministic formulations for the single and multicommodity cases, which offer a general modeling framework for this class of problems, and which account for its specific characteristics: the space and time dependency of events, substitutions among container types, relationships with partner companies, imports and exports, massive equilibration flows, etc. Finally, we provide a mathematical formulation for handling, in the single commodity case, the uncertainty of demand and supply data that is characteristic of container allocation and distribution problems. Various modeling choices, data requirements, and algorithmic considerations related to the implementation of the models are also discussed.

Parallel Branch-and-Branch Algorithms: Survey and Synthesis

We present a detailed and up-to-date survey of the literature on parallel branch-and-bound algorithms. We synthesize previous work in this area and propose a new classification of parallel branch-and-bound algorithms. This classification is used to analyze the methods proposed in the literature. To facilitate our analysis, we give a new characterization of branch-and-bound algorithms, which consists of isolating the performed operations without specifying any particular order for their execution.

Models for Evaluating and Planning City Logistics Systems

City logistics aims to reduce the nuisances associated to freight transportation in urban areas while supporting their economic and social development. The fundamental idea is to view individual stakeholders and decisions as components of an integrated logistics system. This implies the coordination of shippers, carriers, and movements as well as the consolidation of loads of several customers and carriers into the same environment-friendly vehicles. City logistics explicitly aims to optimize such advanced urban transportation systems. We focus on a challenging city logistics planning issue, the integrated short-term scheduling of operations and management of resources, for the general case involving a two-tiered distribution structure. We investigate the main issues related to the problem, introduce a new problem class, propose both a general model and formulations for the main system components, and identify promising solution avenues.

A Hybrid Genetic Algorithm for Multidepot and Periodic Vehicle Routing Problems

We propose an algorithmic framework that successfully addresses three vehicle routing problems: the multidepot VRP, the periodic VRP, and the multidepot periodic VRP with capacitated vehicles and constrained route duration. The metaheuristic combines the exploration breadth of population-based evolutionary search, the aggressive-improvement capabilities of neighborhood-based metaheuristics, and advanced population-diversity management schemes. Extensive computational experiments show that the method performs impressively in terms of computational efficiency and solution quality, identifying either the best known solutions, including the optimal ones, or new best solutions for all currently available benchmark instances for the three problem classes. The proposed method also proves extremely competitive for the capacitated VRP.

Survey Paper---A Review of Empty Flows and Fleet Management Models in Freight Transportation

The transportation of freight, by any mode, usually generates a significant number of empty vehicle movements. Understanding and controlling this phenomenon is important for all levels of transportation and logistic system planning. In this paper, we propose a taxonomy of empty vehicle flow problems and models and review the existing literature on the subject. Major research trends and perspectives are identified and the advantages of a hierarchically integrated approach for the simultaneous management of empty and loaded freight vehicle movements are discussed.

A hybrid genetic algorithm with adaptive diversity management for a large class of vehicle routing problems with time-windows

The paper presents an efficient Hybrid Genetic Search with Advanced Diversity Control for a large class of time-constrained vehicle routing problems, introducing several new features to manage the temporal dimension. New move evaluation techniques are proposed, accounting for penalized infeasible solutions with respect to time-window and duration constraints, and allowing to evaluate moves from any classical neighbourhood based on arc or node exchanges in amortized constant time. Furthermore, geometric and structural problem decompositions are developed to address efficiently large problems. The proposed algorithm outperforms all current state-of-the-art approaches on classical literature benchmark instances for any combination of periodic, multi-depot, site-dependent, and duration-constrained vehicle routing problem with time windows.

Heuristics for multi-attribute vehicle routing problems: A survey and synthesis

The attributes of vehicle routing problems are additional characteristics or constraints that aim to better take into account the specificities of real applications. The variants thus formed are supported by a well-developed literature, including a large variety of heuristics. This article first reviews the main classes of attributes, providing a survey of heuristics and meta-heuristics for Multi-Attribute Vehicle Routing Problems (MAVRP). It then takes a closer look at the concepts of 64 remarkable meta-heuristics, selected objectively for their outstanding performance on 15 classic MAVRP with different attributes. This cross-analysis leads to the identification of “winning strategies” in designing effective heuristics for MAVRP. This is an important step in the development of general and efficient solution methods for dealing with the large range of vehicle routing variants.