4 présentations

• 
  10h30 - 10h55

  E-commerce Middle-mile Network Design with Delivery Speed Choices and Service Level Constraints

  • Aditya Malik, Supply Chain Consulting, NTT DATA Canada Inc
  • Shuvabrata Chakraborty, Indian Institute of Management Raipur
  • Sachin Jayaswal, prés., Indian Institute of Management Ahmedabad

  The increasing demand for expedited e-commerce deliveries, with delivery times of one to three days, highlights the importance of optimizing the middle-mile network. Most retailers store a considerable portion of their inventory at the Regional Distribution Centers (RDCs) outside urban areas, from where it is moved to the customer zones equipped with last-mile distribution facilities as required. Thus, RDC locations become critical in middle-mile operations, directly impacting the transit times to customer zones and, ultimately, the delivery times in the last mile. This paper presents a middle-mile network design problem arising in the context of e-commerce companies in the presence of customers with different delivery time preferences. Specifically, it allows RDCs to satisfy demands from customer zones using delivery times longer than requested, albeit with penalties, if that helps reduce cost without violating the service level requirements of fulfilling at least a given threshold of the demands within the requested delivery times. The problem is formulated as an MILP, for which an exact Lagrangian relaxation-based branch-and-bound algorithm is proposed. Further, several enhancements of the algorithm are provided, which include an efficient heuristic for the primal bound, Benders decomposition to solve one of the Lagrangian sub-problems efficiently, and an analytical approach for obtaining the Benders optimality cuts. With these enhancements, our final algorithm substantially outperforms the state-of-the-art commercial solver, as highlighted by our computational experiments on an extensive set of 200 instances with up to 80 potential RDC locations, 1000 customer zones, and 3 (4) delivery speed options for customer zones (RDCs). Our best algorithm solves 187 of the 200 instances to 0.50% duality gap compared with only 99 that CPLEX could solve to the same gap within an allowed 10-hour CPU time limit. Furthermore, it achieves an average time savings of 64.29% compared with CPLEX across all the instances.

• 
  10h55 - 11h20

  Deciding on Number of Services, Pricing Strategy and Location in Retail Industry in the Existence of Pre-Established Competitor in Heterogeneous Markets

  • Asvadi Saman, prés., PhD Candidate, John Molson School of Business
  • Satyaveer Chauhan, Professor, John Molson School of Business

  In this paper, we study a market with an established retailer and a new entrant aiming to compete. The new retailer optimizes its location and services to attract customers from the incumbent. Stackelberg game theory is used to optimize the new retailer's decisions. The market consists of two customer types: economy and premium, distributed along a linear space. The reservation price and service utility differ for these two types. We examine two scenarios: the first with customers uniformly dispersed, and the second with a non-uniform distribution, where each customer group is more concentrated at opposite ends of the market.

• 
  11h20 - 11h45

  Reducing Emissions in a Multimodal Mobility Hub System: The Effect of Electrification

  • Ali Akbar Sadat Asl, prés., Polytechnique Montreal
  • Hugues Delmaire, Polytechnique Montreal
  • Antoine Legrain, Polytechnique Montréal
  • Francois Soumis, GERAD et Polytechnique

  Ridesharing offers a promising solution to urban mobility challenges by providing affordability and convenience while reducing congestion and environmental impact. This work proposes a system for multimodal mobility hubs equipped with parking facilities, integrating personal vehicles with carpooling options and shuttle services into a cohesive network designed to accommodate real-time inbound and outbound ride requests. A column generation approach is employed to optimize the environmental impact associated with the life cycle emissions of vehicles. Furthermore, the study evaluates the effects of increased electrification by analyzing the transition from internal combustion engine vehicles to electric vehicles under different energy mixes and levels of adoption.

• 
  11h45 - 12h10

  Flexibility in fulfillment for online retailing with green orders

  • Imen Ben Mohamed@, prés., Emlyon Business School
  • Yann Bouchery, The Centre of Excellence in Supply Chain (CESIT), Kedge Business School, Bordeaux, France
  • Walid Klibi, The Centre of Excellence in Supply Chain (CESIT), Kedge Business School, Bordeaux, France

  Consumers become increasingly aware of the environmental impact of e-commerce deliveries, and companies have started proposing green delivery options. These options can take several forms, but customers are more likely to accept longer click-to-possession times than paying extra for green deliveries. This additional delay can help companies improve their environmental impact by consolidating shipments, but this also enables some additional leniency for order fulfillment (preparation and delivery). This creates some interesting decision problems. This paper studies the impact of time flexibility in fulfillment when a retailer offers a green order delivery. Our model decides on a given day whether to prepare or to postpone uncertain green orders, given the customer's willingness to wait and uncertain remaining preparation and transportation capacities. A multi-stage stochastic programming model is proposed. Building on a real case from an 'omnichannel' retail in Europe, results confirm the system dynamics and the value of time flexibility.