• A branch and price approach for deployment of multi-tier software services in clouds 

      Gullhav, Anders Nordby; Nygreen, Bjørn (Journal article; Peer reviewed, 2016)
      This paper considers a service deployment problem that combines service placement and replication level decisions in a cloud computing context. The services are composed of multiple components that are to be placed on nodes ...
    • A maritime inventory routing problem with stochastic sailing and port times 

      Agra, Agostinho; Christiansen, Marielle; Delgado, Alexandrino; Hvattum, Lars Magnus (Journal article; Peer reviewed, 2015)
      This paper describes a stochastic short sea shipping problem where a company is responsible for both the distribution of oil products between islands and the inventory management of those products at consumption storage ...
    • A shortest-path-based approach for the stochastic knapsack problem with non-decreasing expected overfilling costs 

      Range, Troels Martin; Kozlowski, Dawid; Petersen, Niels Christian (Journal article; Peer reviewed, 2018)
      The knapsack problem (KP) is concerned with the selection of a subset of multiple items with known positive values and weights such that the total value of selected items is maximized and their total weight does not exceed ...
    • A two-phase heuristic for an in-port ship routing problem with tank allocation 

      Wang, Xin; Arnesen, Mari Jevne; Fagerholt, Kjetil; Gjestvang, Magnhild; Thun, Kristian (Journal article; Peer reviewed, 2017)
      This paper addresses an in-port ship routing problem with tank allocation that arises in the chemical shipping industry. The aim is to optimize a tanker’s port call operation that integrates sequencing decisions for visiting ...
    • An effective heuristic for solving a combined cargo and inventory routing problem in tramp shipping 

      Hemmati, Ahmad; Stålhane, Magnus; Hvattum, Lars Magnus; Andersson, Henrik (Journal article; Peer reviewed, 2015)
      In this paper a vendor managed inventory (VMI) service in tramp shipping is considered. VMI takes advantage of introducing flexibility in delivery time and cargo quantities by transferring inventory management and ordering ...
    • The Aquaculture Service Vessel Routing Problem with Time Dependent Travel Times and Synchronization Constraints 

      Lianes, Ingeborg Margrete; Noreng, Maren Theisen; Fagerholt, Kjetil; Slette, Hans Tobias; Meisel, Frank (Journal article; Peer reviewed, 2021)
      This paper studies the Aquaculture Service Vessel Routing Problem (ASVRP), which is an important planning problem arising in sea-based fish farming. In the ASVRP, there is a set of fish farms located in the sea, where each ...
    • Bi-objective offshore supply vessel planning with costs and persistence objectives 

      Borthen, Thomas; Loennechen, Henrik; Fagerholt, Kjetil; Wang, Xin; Vidal, Thibault (Journal article; Peer reviewed, 2019)
      This paper introduces a bi-objective model for the offshore supply vessel planning problem (SVPP) in the oil & gas industry. The SVPP consists of determining a new weekly plan for sailing the platform supply vessels whenever ...
    • A branch-and-cut embedded matheuristic for the inventory routing problem 

      Skålnes, Jørgen; Vadseth, Simen Tung; Andersson, Carl Henrik; Stålhane, Magnus (Peer reviewed; Journal article, 2023)
      This paper presents an improved version of the solution method that won the inventory routing problem track of the DIMACS Implementation Challenge. The solution method is a branch-and-cut embedded matheuristic where a ...
    • An exact solution method for a rich helicopter flight scheduling problem arising in offshore oil and gas logistics 

      Nafstad, Gaute Messel; Haugseth, Amund; Høyland, Vebjørn; Stålhane, Magnus (Peer reviewed; Journal article, 2020)
      This paper studies the problem of creating an optimal flight schedule for a heterogeneous fleet of helicopters tasked with transporting personnel to, from, and between offshore installations. The problem can be modelled ...
    • The Fish Feed Production Routing Problem 

      Brekkå, Ivar; Randøy, Solveig; Fagerholt, Kjetil; Thun, Kristian; Vadseth, Simen Tung (Peer reviewed; Journal article, 2022)
      This paper introduces the fish feed production routing problem (FFPRP) faced by Norwegian salmon feed producers. The FFPRP is comprised of a production scheduling problem and a rich vehicle routing problem (VRP) and thus ...
    • 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 ...
    • An iterative matheuristic for the inventory routing problem 

      Vadseth, Simen Tung; Andersson, Henrik; Stålhane, Magnus (Peer reviewed; Journal article, 2021)
      The paper considers the inventory routing problem with the Maximum Level replenishment policy. Here, the supplier is in charge of replenishing goods to a number of customers and can decide when, and in what order, these ...
    • Mature offshore oil field development: Solving a real options problem using stochastic dual dynamic integer programming 

      Bakker, Steffen J.; Kleiven, Andreas; Fleten, Stein-Erik; Tomasgard, Asgeir (Peer reviewed; Journal article, 2021)
      Oil and gas companies are facing low output prices and are forced to focus on the development of mature fields. Relevant investment decisions for operators include lifetime-enhancing activities, such as drilling new wells ...
    • A MIP-based heuristic for a single trade routing and scheduling problem in roll-on roll-off shipping 

      Hansen, Jone Reinlund; Fagerholt, Kjetil; Meisel, Frank (Journal article; Peer reviewed, 2022)
      We study a single trade ship routing and scheduling problem for a roll-on roll-off shipping company. Along the given trade, there is a number of contracts for transportation of cargoes between port pairs. Each contract ...
    • Multi-period facility location and capacity expansion with modular capacities and convex short-term costs 

      Stadlerova, Sarka; Schütz, Peter; Tomasgard, Asgeir (Peer reviewed; Journal article, 2023)
      In this paper, we consider a multi-period facility location problem with capacity expansion motivated by the real-world problem of establishing hydrogen production infrastructure in Norway. The problem is formulated using ...
    • 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. ...
    • Scheduling two-way ship traffic for the Kiel Canal: Model, extensions and a matheuristic 

      Meisel, Frank; Fagerholt, Kjetil (Peer reviewed; Journal article, 2019)
      The Kiel Canal is an artificial waterway of about 100 km that connects the North Sea and the Baltic Sea. It allows ships to save several hundred kilometers of travel distance compared with going around the Jutland Peninsula ...
    • The robust vehicle routing problem with time windows 

      Agra, Agostinho; Christiansen, Marielle; Figueiredo, Rosa; Hvattum, Lars Magnus; Poss, Michael; Requejo, Cristina (Journal article; Peer reviewed, 2013)
      This paper addresses the robust vehicle routing problem with time windows. We are motivated by a problem that arises in maritime transportation where delays are frequent and should be taken into account. Our model only ...