Erna Engebrethsen

Engebrethsen, Erna S. & Dauzère-Pérès, Stéphane (2022)

Transportation strategies for dynamic lot sizing: single or multiple modes?

International Journal of Production Research Doi: 10.1080/00207543.2022.2145516

The complexity of decision-making for companies buying transportation services has increased due to the presence of more options and pricing schedules for transportation. Many companies make transportation and inventory decisions in an uncoordinated way and select only one transportation mode, missing opportunities for logistics cost savings. The experimental study in this paper is based on a real-world decision problem faced by a Scandinavian company that distributes fast-moving consumer goods and wants to determine its transportation strategy. We propose a novel multi-mode lot-sizing model with dynamic deterministic demand to illustrate the cost impact of accurately modelling piecewise-linear transportation costs and allowing a more flexible usage of transportation modes when planning order replenishments. We compare three transportation strategies with increasing degrees of flexibility: two single mode strategies, where one strategy is more flexible than the other, and a multi-mode strategy. We conclude that managers can significantly reduce costs by increasing the flexibility of mode selection in transportation strategies.

Engebrethsen, Erna S. & Dauzère-Pérès, Stéphane (2019)

Transportation mode selection in inventory models: A literature review

European Journal of Operational Research, 279, s. 1- 25. Doi: 10.1016/j.ejor.2018.11.067 - Fulltekst i vitenarkiv

Despite the significant share of transportation costs in logistics costs and the importance of considering transportation in inventory models, the majority of the existing models either neglect or simplify transportation costs and capacities, often assuming that only one transportation option is available. The complexity of modeling and choosing the optimal transportation mode or combination of modes has increased due to the increased variety of transportation options and pricing schedules after deregulation. In this paper, we review and classify inventory models with multiple transportation modes focusing on the freight cost functions, mode characteristics and the methods for modeling multiple modes. To our knowledge, no such review has previously been published. We discuss the benefits and weaknesses of each modeling method and, based on industrial practices, identify new areas for research.

Engebrethsen, Erna; alvarez, jose fernando, kakalis, nikolaus & tsilingiris, panagiotis (2011)

Robust Fleet Sizing and Allocation in Industrial and Bulk Ocean Shipping Companies

INFOR: Information Systems and Operational Research, 49(2), s. 93- 107. Doi: 10.3138/infor.49.2.093

alvarez, fernando; Longva, Tore & Engebrethsen, Erna (2010)

A Methodology To Assess Vessel Berthing And Speed Optimization Policies

Maritime Economics & Logistics, 12(4), s. 327- 346.

Tamssaouet, Karim; Engebrethsen, Erna & Dauzère-Pérès, Stéphane (2022)

Multi-item dynamic lot sizing with multiple transportation modes and item fragmentation

[Academic lecture]. International Workshop on Lot Sizing (IWLS 2022).

Engebrethsen, Erna S. & van Oorschot, Kim (2022)

Blockchain as a risk management enabler for medicine supply chains: practical challenges and research opportunities

[Academic lecture]. Annual Conference of the Norwegian Operations Research Society.

Jahre, Marianne; Bygballe, Lena Elisabeth & Engebrethsen, Erna S. (2017)

Collaborative approach to reduce risks and improve crisis management – the BaSEC case

[Academic lecture]. SNF Workshop Series: Methods of Disaster Research: Interdisciplinary Approaches.