• An exact solution method for the capacitated item-sharing and crowdshipping problem 

      Behrend, Moritz; Meisel, Frank; Fagerholt, Kjetil; Andersson, Henrik (Peer reviewed; Journal article, 2019)
      The item-sharing and crowdshipping problem combines two concepts of the sharing economy, namely item-sharing and crowdshipping. Item-sharing is about renting items among members of a sharing community. Crowdshipping addresses ...
    • Green Tramp Shipping Routing and Scheduling: Effects of Market-Based Measures on CO2 Reduction 

      Wang, Xin; Norstad, Inge; Fagerholt, Kjetil; Christiansen, Marielle (Chapter, 2019)
      In this chapter we examine, from a tramp ship operator’s point of view, how potential CO2 emission reduction measures impact the operational decisions and their economic and environmental consequences. Two market-based ...
    • Heuristics for dynamic and stochastic routing in industrial shipping 

      Tirado, Gregorio; Hvattum, Lars Magnus; Fagerholt, Kjetil; Cordeau, Jean-François (Journal article; Peer reviewed, 2012)
      Maritime transportation plays a central role in international trade, being responsible for the majority of long-distance shipments in terms of volume. One of the key aspects in the planning of maritime transportation systems ...
    • Impact of simulation model fidelity and simulation method on ship operational performance evaluation in sea passage scenarios 

      Nielsen, Jørgen Bremnes; Sandvik, Endre; Pedersen, Eilif; Asbjørnslett, Bjørn Egil; Fagerholt, Kjetil (Journal article; Peer reviewed, 2019)
      In this paper, we present and investigate important factors that influence a vessels fuel consumption during operation and what model fidelity that is required to adequately capture these factors in fuel consumption ...
    • Industrial and Tramp Ship Routing Problems: Closing the Gap for Real-Scale Instances 

      Homsi, Gabriel; Martinelli, Rafael; Vidal, Thibaut; Fagerholt, Kjetil (Peer reviewed; Journal article, 2019)
      Recent studies in maritime logistics have introduced a general ship routing problem and a benchmark suite based on real shipping segments, considering pickups and deliveries, cargo selection, ship-dependent starting ...
    • Kindergarten allocation in Norway: An integer programming approach 

      Geitle, Anders Hasson; Johnsen, Øyvind Knutsen; Ruud, Håkon Fredrik; Fagerholt, Kjetil; Julsvoll, Carl Andreas (Peer reviewed; Journal article, 2020)
      Kindergartens are vital to society in many countries, and in Norway, the municipalities are the local authorities that facilitate a coordinated admission process involving all their kindergartens. Allocating children to ...
    • Maritime crude oil transportation – A split pickup and split delivery problem 

      Hennig, Frank; Nygreen, Bjørn; Christiansen, Marielle; Fagerholt, Kjetil; Furman, Kevin C; Song, Jinhwa; Kocis, Gary R; Warrick, Philip H (Journal article; Peer reviewed, 2012)
      The maritime oil tanker routing and scheduling problem is known to the literature since before 1950. In the presented problem, oil tankers transport crude oil from supply points to demand locations around the globe. The ...
    • Maritime fleet deployment in ro-ro shipping under inventory constraints 

      Chandra, Saurabh; Fagerholt, Kjetil; Christiansen, Marielle (Journal article; Peer reviewed, 2015)
      We present a tactical maritime fleet deployment problem in roll-on roll-off (ro-ro) liner shipping scenario, which deals with optimally assigning planned voyages to the available vessels in a fleet to determine the routing ...
    • Maritime fleet deployment with speed optimization and voyage separation requirements 

      Borander, Venke; Straume, Anders; Dong, Bo; Fagerholt, Kjetil; Wang, Xin (Journal article; Peer reviewed, 2018)
      A shipping company operates a heterogeneous fleet of ships to service a given number of voyages on a number of trade routes over the planning horizon. Each ship has a predefined speed range within which it can sail. Fuel ...
    • Maritime routing and speed optimization with emission control areas 

      Fagerholt, Kjetil; Gausel, Nora Therese; Rakke, Jørgen Glomvik; Psaraftis, Harilaos (Journal article; Peer reviewed, 2015)
      Strict limits on the maximum sulphur content in fuel used by ships have recently been imposed in some Emission Control Areas (ECAs). In order to comply with these regulations many ship operators will switch to more expensive ...
    • Maximizing the rate of return on the capital employed in shipping capacity renewal 

      Mørch, Ove; Fagerholt, Kjetil; Pantuso, Giovanni; Rakke, Jørgen Glomvik (Journal article; Peer reviewed, 2017)
      Decisions regarding investments in capacity expansion/renewal require taking into account both the operating fitness and the financial performance of the investment. While several operating requirements have been considered ...
    • Offshore supply planning in a rolling time horizon 

      Fernandez Cuesta, Eirik; Andersson, Henrik; Fagerholt, Kjetil (Journal article; Peer reviewed, 2018)
      This paper presents a real transportation problem stemming from offshore oil and gas logistics and shows how optimization models used in a rolling horizon simulation framework can be very valuable to assess and improve the ...
    • On two speed optimization problems for ships that sail in and out of emission control areas 

      Fagerholt, Kjetil; Psaraftis, Harilaos (Journal article; Peer reviewed, 2015)
      This paper deals with two speed optimization problems for ships that sail in and out of Emission Control Areas (ECAs) with strict limits on sulfur emissions. For ships crossing in and out of ECAs, such as deep-sea vessels, ...
    • Operational planning for routes and schedules for a fleet of fuel supply vessels 

      Christiansen, Marielle; Fagerholt, Kjetil; Rachaniotis, Nikos; Stålhane, Magnus (Journal article; Peer reviewed, 2017)
      This paper considers a real operational problem of routing and scheduling a fleet of fuel supply vessels used to service customer ships anchored outside a major port. The problem can be formulated as a rich multi-trip ...
    • Optimal Charging and Repositioning of Electric Vehicles in a Free-Floating Carsharing System 

      Folkestad, Carl Axel Aadne; Hansen, Nora Åsheim; Fagerholt, Kjetil; Andersson, Henrik; Pantuso, Giovanni (Journal article; Peer reviewed, 2019)
      Carsharing has received increased attention from the Operations Research community in recent years. Currently, many systems are adopting electric vehicles that require charging when battery levels fall below a given level. ...
    • Optimisation of the broiler production supply chain 

      Brevik, Elisabeth; Lauen, Anna Ødegaard; Rolke, Maria Cathrine Berg; Fagerholt, Kjetil; Hansen, Jone Reinlund (Peer reviewed; Journal article, 2020)
      In this paper, we propose a mixed integer programming (MIP) model for the Chicken Flock Sizing, Allocation and Scheduling Problem (CFSASP), which is an important planning problem in the broiler production supply chain. To ...
    • Optimization in offshore supply vessel planning 

      Halvorsen-Weare, Elin Espeland; Fagerholt, Kjetil (Journal article; Peer reviewed, 2016)
      This paper considers the offshore supply vessel (OSV) planning problem, which consists of determining an optimal fleet size and mix of OSVs as well as their weekly routes and schedules for servicing offshore oil and gas ...
    • Planning for charters: A stochastic maritime fleet composition and deployment problem 

      Wang, Xin; Fagerholt, Kjetil; Wallace, Stein W. (Journal article; Peer reviewed, 2017)
      This paper introduces a chartering problem that arises in the shipping industry. The chartering decisions determine the time-charter contracts to enter into, in particular, how many ships of each type to charter in, and ...
    • Planning interrelated voyages with separation requirements in roll-on roll-off shipping 

      Hansen, Jone Reinlund; Fagerholt, Kjetil; Meisel, Frank; Rakke, Jørgen Glomvik (Peer reviewed; Journal article, 2019)
      We consider a new problem of planning interrelated voyages with separation requirements along a single trade in roll-on roll-off shipping. Along a given trade with a sequence of port calls, there is a number of contracts ...
    • Risk Control in Maritime Shipping Investments 

      Skålnes, Jørgen; Fagerholt, Kjetil; Pantuso, Giovanni; Wang, Xin (Journal article; Peer reviewed, 2019)
      In this paper we extend the state-of-the-art stochastic programming models for the Maritime Fleet Renewal Problem (MFRP) to explicitly limit the risk of insolvency due to negative cash flows when making maritime shipping ...