4 Presentations

• 
  10:30 AM - 10:52 AM

  Strategic Logistics Service Provider Selection Influenced by Relationships, Cost and Market Dynamics - A Multi-Factorial Case Study

  • Torben Tambo, presenter, Aarhus University

  Selection of logistics service providers (LSPs) is regarded critical and complex. Relationships tend to last for many years and have a critical role in the architecting of supply chains. Occasionally, relationships between buyer and LSP come to a crossroad of termination, extension or change; attrition of relationships can be caused by poor quality, changed market conditions, changed management, changed operational conditions on either side, and moves from competitors. This study uses a case-based methodology to provide an in-depth account of business motivations in relationship development in LSP selection. The study presents a tendering process as a fulcrum of „non-conformant‟ behaviour and unexpected outcome. Major findings are that contract-bound services and cost structures seem to drift into less transparent and informal patterns of interactions over time; this is wearing on the business relationship. Extreme fluctuations in the market – not sufficiently rapidly recognised by the LSPs – also put wear on relationship. In the case were relationships are too stressed, everything comes into play; newcomers might have good chances even if both parties should expect history to repeat itself. This paper could contribute to deepened understanding of both sides in either utilising the unexpected or to struggle harder for conflict resolution in relationships. Further implications are the presented processes as a background for volatility in global supply chains and radical changes in logistics services.

• 
  10:52 AM - 11:14 AM

  A Heuristic Approach for Bid Construction in Combinatorial Auctions for the Procurement of TL Transportation Services

  • Intissar Ben Othman, presenter, Université Laval
  • Mohamed Khalil Elloumi, INSAT, Tunis
  • Monia Rekik, Université Laval
  • Sehl Mellouli, Université Laval

  This paper proposes a heuristic approach for constructing combinatorial bids in transportation procurement auctions. We consider a context where a single shipper submits a number of transportation contracts to a set of participating carriers. Each carrier will analyse these new contracts and try to insert them in its existing transportation network in order to increase its profits. We propose to formulate this bid construction problem (BCP) with a particular graph using super nodes in which only profitable nodes need to be visited. The output of the heuristic is a combinatorial bid, i.e., a package of new contracts and an associated interval of ask prices that the carrier would gain by submitting. Preliminary computing results are promising.

• 
  11:14 AM - 11:36 AM

  A 2-Stage Robust Formulation for the Winner Determination Problem in Combinatorial Transportation Auctions under Uncertain Demands

  • Nabila Remli, presenter, CIRRELT
  • Monia Rekik, Université Laval

  Combinatorial auctions are widely used for the procurement of transportation services. In such auctions, shippers act as auctioneers who need to outsource a number of transportation services on given lanes (i.e., origin-destination pairs) to some external carriers. Carriers, the bidders of the auction, compete by submitting bids on packages of shippers’ requests. After receiving all carriers’ bids, the shipper solves the well-known winner determination problem (WDP) in order to determine winning bids that satisfy its transportation needs while minimizing its total transportation cost. This paper deals with a variant of the WDP in the context where shipment volumes on lanes are not known with certainty. The paper investigates a robust optimization methodology to handle this uncertainty. Based on the bi-level characteristic of the problem, a simplified 2-stage robust formulation is proposed and solved using a constraint generation algorithm. Preliminary experimental results are promising to solve large size instances.

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  11:36 AM - 11:58 AM

  Conceptual Framework for Strategic and Operational Decision Making for Carriers Selection

  • Meriem Mettichi, ENIT, Tunis
  • Yassin Feki, presenter, Université Laval
  • Monia Rekik, Université Laval
  • Adnène Hajji, Université Laval

  This paper addresses the carrier’s selection problem at both the strategic and the operational levels. A con-ceptual framework is proposed to handle both levels. The strategic selection uses a combinatorial auction mechanism in which carriers compete by submitting package bids on shippers’ requests. A MIP model is used to determine winning carriers with which the shipper will engage on a long period. At the operational level, an LP model is proposed to se-lect carriers with the objective of minimizing inventory, backorder and transportation costs. This model is governed by some information available from the strategic level and uses other information available at the operational level. Some preliminary results are presented and show the usefulness of the proposed framework.