• A General Deep Reinforcement Learning Hyperheuristic Framework for Solving Combinatorial Optimization Problems
    J Kallestad, R Hasibi, A Hemmati, K Sörensen
    European Journal of Operational Research 2023;


  • Solving a Pick-up and Delivery Routing Problem for Fourth Party Logistics Providers
    P Bucher Johannessen, A Hemmati, M Moshref-Javadi
    International Transactions in Operational Research 2022; 
  • Polyhedral results and stronger Lagrangean bounds for stable spanning trees
    P Samer, D Haugland
    Optimization Letters, 2022. 
  • The Lagrangian, constraint qualifications and economics
    SD Flåm, JJ Rückmann
    Math. Methods Oper. Research 2022 ;Volum 96-2. s. 215-232
  • Some properties of K-convex mappings in variable ordering settings
    G Bouza Allende, D Hernandez Escobar, JJ Rückmann
    Optimization, electronically published, DOI: https://doi.org/10.1080/02331934.2021.1937159
  • A Story of Computational Science: Colonel Titus’ Problem from the 17th Century
    T Steihaug
    Axioms 2022; 11 (6), 287


  • A comparative analysis of synchronized truck-and-drone delivery models
    M Moshref-Javadi, A Hemmati, M Winkenbach
    Computers & Industrial Engineering 2021; 162, 107648
  • Fixed cardinality stable sets
    P Samer, D Haugland
    Discrete Applied Mathematics 2021; 303, pp.137-148
  • Optimization of reliable cyclic cable layouts in offshore wind farms
    A Klein, D Haugland
    Engineering Optimization 2021; 53(2), pp.258-276
  • MPCC: Strong Stability of M-stationary Points
    H Günzel, D Hernandez Escobar, JJ Rückmann
    Set-Valued and Variational Analysis 2021; 29 (3), 645-659
  • Strongly stable C-stationary points for mathematical programs with complementarity constraints
    D Hernandez Escobar, JJ Rückmann
    Mathematical Programming 2021; 189 (1), 339-377
  • On shared use of renewable stocks
    NA Ekerhovd, SD Flåm, SI Steinshamn
    European Journal of Operational Research 2021; 290 (3), 1125-1135

  • Games and cost of change
    SD Flåm
    Annals of Operations Research 2021; 301 (1), 107-119

  • Market equilibria and money
    SD Flåm
    Fixed Point Theory and Algorithms for Sciences and Engineering  2021; (1), 1-18

  • Towards competitive equilibrium by double auctions. 
    SD Flåm
    Pure and Applied Functional Analysis 2021 ;Volum 6.(6) s. 1211-1225
  • Computational Science in the 17th Century. Numerical Solution of Algebraic Equations: Digit–by–Digit Computation
    T Steihaug
    Numerical Analysis and Optimization 2021;


  • A truck and drones model for last-mile delivery: A mathematical model and heuristic approachM Moshref-Javadi, A Hemmati, M WinkenbachApplied Mathematical Modelling 2020; 80, 290-318
  • MPCC: Strongly stable C-stationary points when the number of active constraints is n+1D Hernandez Escobar, JJ RückmannOptimization 2020 ;Volum 69-5. s. 1039-1067
  • Predicting the winners of Borda, Kemeny and Dodgson elections with supervised machine learning. H Kujawska, M Slavkovik, JJ RückmannIn: N. Bassiliades et al. (editors). Multi-Agent Systems and Agreement Technologies. 2020 Springer, New York. s. 440-458
  • Rights and rents in local commonsSD FlåmJournal of Mechanism and Institution Design 2020; 5 (1), 119-140

  • Emergence of price-taking behaviorSD FlåmEconomic Theory 2020; 70 (3), 847-870

  • Computational science in the eighteenth century. Test cases for the methods of Newton, Raphson, and Halley: 1685 to 1745T SteihaugNumerical Algorithms 2020; 83 (4), 1259-1275 


  • On offshore wind farm maintenance scheduling for decision support on vessel fleet compositionA Gutierrez-Alcoba, EMT Hendrix, G Ortega, EE Halvorsen-Weare, D HauglandEuropean Journal of Operational Research 2019; 279(1), pp.124-131

  • Integer programming formulations for the shared multicast tree problemM Ivanova, D HauglandJournal of Combinatorial Optimization 2019; Vol. 38(3), pp.927-956

  • Obstacle-aware optimization of offshore wind farm cable layoutsA Klein, D HauglandAnnals of Operations Research 2019; Vol. 272(1-2), pp.373-388

  • The matching relaxation for a class of generalized set partitioning problemsP Samer, E Cavalcante, S Urrutia, J OppenDiscrete Applied Mathematics, 2019, Volume 253, pp 153-166

  • Preface. Parametric Optimization and Related Topics XI (special issue)M Cervinka, JJ Rückmann, O Stein (guest-editors)Optimization 2019 ;Volum 68-2/3. s. 429-431

  • Surrogate-based model parameter optimization based on gas explosion experimental dataAL Both, H Hisken, JJ Rückmann, T SteihaugEngineering Optimization 2019 ;Volum 51-2. s. 301-316
  • A note on strict complementarity for the doubly nonnegative coneB Jargalsaikhan, JJ RückmannOptimization 2019 ;Volum 68-2/3. s. 457-464
  • MPCC: On necessary conditions for the strong stability of C-stationary points D Hernandez Escobar, JJ RückmannOptimization 2019 ;Volum 68-2/3. s. 593-613
  • Generalized gradients, bid–ask spreads, and market equilibriumSD FlåmOptimization 2019; 68 (2-3), 579-592

  • Blocks of coordinates, stochastic programming, and marketsSD FlåmComputational Management Science 2019; 16 (1), 3-16

  • Primal-dual algorithms for semidefinite optimization problems based on kernel-function with trigonometric barrier termM El Ghami, G Wang, T SteihaugInternational Journal of Applied Mathematics 2019; 32 (2), 333


  • Minimizing the tracking error of cardinality constrained portfoliosP Mutunge, D HauglandComputers & Operations Research 2018 ;Volum 90. s. 33-41
  • Area Protection in Adversarial Path-finding Scenarios with Multiple Mobile Agents on Graphs - A Theoretical and Experimental Study of Strategies for Defense CoordinationM Ivanova, P Surynek, K HirayamaProceedings of the 10th International Conference on Agents and Artificial Intelligence (ICAART), 184-191
  • On measures, pricing and sharing of riskSD FlåmInvestigacion Operacional 2018;Volum 39.(3) s. 326-34
  • Blocks of coordinates, stochastic programming, and marketsSD FlåmComputational Management Science, DOI: 10.1007/s10287-018-0303-3
  • A parametrized stock-recruitment relationship derived from a slow-fast population dynamic modelU Schaarschmidt, T Steihaug, S SubbeyMathematics and Computers in Simulation 145, 171-185
  • Generation of K-convex test problems in variable ordering settingsG Bouza Allende, D Hernandez Escobar, JJ RückmannInvestigacion Operacional 39 (3)

  • On vector generalized semi-infinite programmingF Guerra Vazquez, LA Hernandez Rebollar, JJ RückmannInvestigacion Operacional 39 (3)

  • Variational Analysis and Optimization Theory (special issue)G Bouza Allende, JJ Rückmann, C Tammer (guest-editors)Investigacion Operacional 39 (3) 

  • Approximating cube roots of integers after Heron’s Metrica III.20Steihaug, T. and Rogers, D.NORMAT (Nordic Mathematical Journal), 61(2)

  • A review of termination rules of an inexact primal-dual interior point method for linear programming problemsBaryamureeba, V., Steihaug, T., and El Ghami, M. Revista de Investigacion Operacional, Vol. 39, No. 3



  • Evaluating the importance of randomization in adaptive large neighborhood searchA Hemmati, LM HvattumInternational Transactions in Operational Research 24 (5), 929-942  
  • Response surfaces for advanced consequence models: Two approachesAL Braatz, H HiskenJournal of Loss Prevention in the Process Industries 49, 683-699
  • Reaching Cournot-Walras EquilibriumSD Flåm, K GramstadESAIM: Proceedings and Surveys 57, 12-22
  • Order books, markets and convex analysisSD FlåmOptimization 66 (8), 1413-1424
  • A model for optimal fleet composition of vessels for offshore wind farm maintenance,A Gutierrez-Alcoba, G Ortega, EMT Hendrix, EE Halvorsen-Weare, D HauglandProcedia Computer Science 108, 1512-1521
  • Point-based neighborhoods for sharp calmness constants in linear programmingMJ Canovas, J Parra, JJ Rückmann, FJ Toledo Set-Valued and Variational Analysis 25 (4), 757-772
  • On duality in multiobjective semi-infinite optimization F Guerra Vazquez, JJ Rückmann Optimization 66 (8), 1237-1249

  • A tutorial note on a convexification procedure in non-convex semi-infinite programming optimization JJ RückmannInvestigacion Operacional 38 (4), 309-319

  • ISORA 2015 (special issue)JE Martinez Legaz, E Ocana Anaya, JJ Rückmann (guest-editors) Optimization 66 (8) 

  • A new parametric kernel function with trigonometric barrier term for convex quadratic symmetric cone optimizationWang, G.Q, El Ghami, M and Steihaug, TApplied Analysis and Optimization

  • A New Parametric Kernel Function Yielding the Best Known Iteration Bonds of Interior Point Methods for the Cartesian P∗(κ)-SCLCP Cai, X.Z., Wang, D.Z., El Ghami, M; Steihaug, T., and Wang, G. Pacific Journal of Optimization 



  • An iterative two-phase hybrid matheuristic for a multi-product short sea inventory-routing problemA Hemmati, LM Hvattum, M Christiansen, G LaporteEuropean Journal of Operational Research 252 (3), 775-788 
  • Response surfaces for advanced consequence models: two approachesAL Braatz, H Hisken11th International Symposium on Hazards, Prevention, and Mitigation of Industrial Explosions (XI ISHPMIE)
  • Surrogate-based optimisation of model parameters for the improved modelling of industrial-scale gas explosionsAL Braatz, H Hisken, JJ Rückmann5th International Conference on Engineering Optimization (EngOpt 2016)
  • The Shared Broadcast Tree Problem and MSTM IvanovaElectronic Notes in Discrete Mathematics 55, 5-8
  • Shared Multicast Trees in Ad Hoc Wireless NetworksM IvanovaCombinatorial Optimization - 4th International Symposium (ISCO), 273-284
  • Borch's theorem, equal margins, and efficient allocationSD FlåmInsurance, Mathematics & Economics 70, 162-168
  • Noncooperative games, coupling constraints, and partial efficiencySD FlåmEconomic Theory Bulletin 4 (2), 213-229
  • Monotonicity and market equilibriumSD FlåmSet-Valued and Variational Analysis 24 (3), 403-421
  • Bilateral exchange and competitive equilibriumSD FlåmSet-Valued and Variational Analysis 24 (1), 1-11
  • Pooling Problems with Polynomial-Time AlgorithmsD Haugland, EML HendrixJournal of Optimization Theory and Applications 170 (2), 591-615
  • The computational complexity of the pooling problemD HauglandJournal of Global Optimization, 64 (2), 199-215
  • A continuously differentiable turbine layout optimization model for offshore wind farmsA KleinEnergy Procedia, 94, 497-503
  • Tight semi-model-free bounds on (bilateral) CVA J Helmers, JJ Rückmann, R Werner In: K Glau et al. (editors), Innovations in Derivatives Markets, Springer, New York, 83-101

  • A tutorial note on multiobjective semi-infinite programmingJJ Rückmann Investigacion Operacional 37 (3), 216-225

  • On the final steps of Newton and higher order methodsSteihaug, T., and Suleiman, S. Optimization Letters, Vol. 10(2), pp 401-416


  • An effective heuristic for solving a combined cargo and inventory routing problem in tramp shippingA Hemmati, M Stålhane, LM Hvattum, H AnderssonComputers & Operations Research 64, 274-282
  • Control of adsorption chillers by a gradient descent method for optimal cycle time allocationU Bau, AL Braatz, F Lanzerath, M Herty, A BardowInternational Journal of Refrigeration 56, 52-64
  • Optimization models and methods for maritime cargo and inventory routing problemsA HemmatiNTNU  
  • Risk Measures, Convexity, and Max-Min ShortfallsSD FlåmJournal of Convex Analysis 22 (3), 603-626
  • Liability Insurance and Choice of Cars: A Large Game ApproachSD Flåm, EG WolfstetterJournal of Public Economic Theory 17 (6), 943-963
  • Ragnar Frisch and interior-point methodsO Bjerkholt, SD FlåmOptimization Letters 9 (6), 1053-1061
  • Optimal intake and routing of floating oil rigs in the North SeaD Haugland, BP TjøstheimIn KG Murty (ed.): Case Studies in Operations Research: Applications of Optimal Decision Making, International Series in Operations Research & Management Science, 212, 315-336
  • On a pooling problem with fixed network sizeD Haugland, EML HendrixLecture Notes in Computer Science, 9335, 328-342
  • An Integer Programming Model for Branching Cable Layouts in Offshore Wind FarmsA Klein, D Haugland, J Bauer, M MommerAdvances in Intelligent Systems and Computing, 359 (1), 27-36
  • Derivative-free optimization for population dynamic modelsU Schaarschmidt, T Steihaug, S SubbeyIn HA Le Thi, T Pham Dinh, NT Nguyen (eds.): Modelling, Computation and Optimization in Information Systems and Management Science, 391-402, Springer, Cham
  • Multiobjective semi-infinite optimization: convexification and properly efficient points F Guerra Vazquez, JJ RückmannIn: GO Tost et al. (editors), Analysis, Modelling, Optimization, and Numerical Techniques, Springer, New York, 327-347


  • Benchmark suite for industrial and tramp ship routing and scheduling problemsA Hemmati, LM Hvattum, K Fagerholt, I NorstadINFOR: Information Systems and Operational Research 52 (1), 28-38 
  • A simulated annealing algorithm for routing problems with fuzzy constrainsMHF Zarandi, A Hemmati, S Davari, IB TurksenJournal of Intelligent & Fuzzy Systems 26 (6), 2649-2660  
  • Adversarial Cooperative Path-Finding: Complexity and AlgorithmsM Ivanova, P Surynek26th IEEE International Conference on Tools with Artificial Intelligence (ICTAI), 75-82
  • Gradient differences and bilateral bartersSD Flåm, O Godal, A SoubeyranOptimization 63 (5), 693-712
  • A cost minimization heuristic for the pooling problemM Alfaki, D HauglandAnnals of Operations Research, 222 (1), 73-87
  • Modeling and forecasting stock recruitment: Current and future perspectivesS Subbey, JA Devine, U Schaarschmidt, RDM NashICES Journal of Marine Science 71 (8), 2307-2322
  • On the local representation of piecewise smooth equations as a Lipschitz manifoldD Dorsch, HT Jongen, JJ Rückmann, V Shikhman J. Math. Anal. Appl. 411, 916-930

  • On proper efficiency in multiobjective semi-infinite optimization F Guerra Vazquez, JJ Rückmann In: H Xu et al. (editors), Optimization and Control Techniques and Applications, Springer, New York, 115-135

  • Algorithm for forming derivative-free optimal methodsKhattri, SK., and Steihaug, T.Numerical Algorithms; Vol. 65(4) pp. 809-824

  • A Subclass of Generating Set Search with Convergence to Second-Order Stationary PointsAbramson, M., Frimannslund, L., and Steihaug, T.Optimization Methods and Software;Vol. 29(5)pp 900-918


  • Capacitated location-routing problem with time windows under uncertaintyMHF Zarandi, A Hemmati, S Davari, IB TurksenKnowledge-Based Systems 37, 480-489    
  • Adversarial Cooperative Path-Finding: A First ViewM Ivanova, P SurynekLate-Breaking Developments in the Field of Artificial Intelligence, 53-55
  • Optimization methods for pipeline transportation of natural gas with variable specific gravity and compressibilityC Borraz-Sànchez, D HauglandTOP - an official journal of the Spanish Society of Statistics and Operations Research, 21 (3), 524-541
  • Strong formulations for the pooling problemM Alfaki, D HauglandJournal of Global Optimization, 56 (3), 897-916
  • A multi-commodity flow formulation for the generalized pooling problemM Alfaki, D HauglandJournal of Global Optimization, 56 (3), 917-937
  • MIDACO on MINLP Space Applications S Erb, M Gerdts, S Kemble, JJ Rückmann, M Schlüter Advances in Space Research 51 (7), 1116-1131

  • A note on logarithmic smoothing in semi-infinite optimization under reduction approach F Guerra Vazquez, JJ Rückmann Croatian OR Review 4, 19-30

  • Rate of convergence of higher order methodsSteihaug, T., and Suleiman, S.Applied Numerical Mathematics. Vol. 67, pp. 230–242

  • Graph models and their efficient implementation for sparse Jacobian matrix determinationHossain, S., and Steihaug, T.Discrete Applied Mathematics 2013; Vol. 161(12) pp. 1747-1754

  • Structure in Optimization: Factorable Programming and FunctionsHascoêt, L., Hossain, S., and Steihaug, T.In: Computer and Information Sciences III.  pp. 449-458, Springer

  • Structured computation in optimization and Algorithmic DifferentiationHascoêt, L., Hossain, S., and Steihaug, T.ACM Communications in Computer Algebra; Vol. 46(3) Suppl. Issue: 181 pp. 94-95

  • Solving trust-region subproblem augmented with linear inequality constraintsBergmann, Ø., and Steihaug, T.Optimization Methods and Software; Vol. 28(1) pp. 26-36

  • Computational and Sensitivity Aspects of Eigenvalue-Based Methods for the Large-Scale Trust-Region SubproblemRojas, M., Fotland, B., and Steihaug, T. Optimization Methods and Software; Vol. 28(3) pp. 564-580

  • Global convergence and the Powell singular functionSteihaug, T., and Suleiman, S.Global Optimization; Vol. 56(3) pp. 845-853

  • Optimal Direct Determination of Sparse Jacobian Matrices Hossain, S., and Steihaug, T.Optimization Methods and Software; Vol. 28(6) pp.1218-1232

  • Sparse matrix computations with application to solving system of nonlinear equationsHossain, S., and Steihaug, T. Wiley Interdisciplinary Reviews: Computational Statistics; Vol. 5(5) pp. 372-386

  • Adaptive Curve TailoringSteihaug, T., and Wang, W.  In: Information Sciences and Systems pp.3-13, Springer



  • Dual decomposition for computational optimization of minimum-power shared broadcast tree in wireless networksD Yuan, D HauglandIEEE Transactions on Mobile Computing, 11 (12), 2008-2019
  • Computing the Optimal Layout of a Wind Farm.JK Haugland, D HauglandIn Norsk informatikkonferanse (NIK 2012), ISSN 1892-0713, Akademika forlag
  • Parallel algorithms for the maximum flow problem with minimum lot sizesM Eleyat, D Haugland, ML Hetland, L NatvigOperations Research Proceedings 2011, 83-88, ISBN 978-3-642-29209-5, Springer
  • SIP: critical value functions have  finite modulus of non-convexity D Dorsch, F Guerra Vazquez, H Günzel, HT Jongen, JJ RückmannMathematical Programming 136 (1), 133-154

  • Parametric Optimization and Related Topics X (special issue)JJ Rückmann, O Stein (guest-editors) Optimization 61 (6) 

  • A numerical study of MIDACO on 100 MINLP benchmarks M Gerdts, JJ Rückmann, M Schlüter Optimization 61 (7), 873-900

  • On saddle points in nonconvex semi-infinite programmingF Guerra Vazquez, JJ Rückmann, R Werner J. Global Optimization 54 (3), 433-447

  • Parametric Optimization and Related Topics (special issue)JJ Rückmann, O Stein (guest-editors) Mathematical Programming 136 (1) 

  • Semi-infinite programming: strong stability implies EMFCQ D Dorsch, F Guerra Vazquez, H Günzel, JJ Rückmann J. Convex Analysis 19 (4), 999-1008

  • On diagonally structured problems in unconstrained optimization using an inexact super Halley methodGundersen, G. and Steihaug, T.Journal of Computational and Applied Mathematics; Vol. 236(15) pp. 3685-3695

  • Interior-point methods for linear optimization based on a kernel function with a trigonometric barrier termEl Ghami, M., Guennoun, Z, Bouali, S., and Steihaug, T.Journal of Computational and Applied Mathematics; Vol. 236(15) pp. 3613-3623

  • Sparsity in higher order methods for unconstrained optimizationGundersen, G., and Steihaug, T.Optimization Methods and Software, Vol. 27(2), pp.275-294


  • The multi-depot capacitated location-routing problem with fuzzy travel timesMHF Zarandi, A Hemmati, S DavariExpert Systems with Applications 38 (8), 10075-10084    
  • Maximal covering location problem (MCLP) with fuzzy travel timesS Davari, MHF Zarandi, A HemmatiExpert Systems with Applications 38 (12), 14535-14541  
  • Minimizing fuel cost in gas transmission networks by dynamic programming and adaptive discretizationC Borraz-Sànchez, D HauglandComputers & Industrial Engineering, 61, 364-372
  • Local search heuristics for the probabilistic dial-a-ride problemSC Ho, D HauglandOR Spectrum, 33 (4), 961-988
  • The maximum flow problem with minimum lot sizesD Haugland, M Eleyat, ML HetlandLecture Notes in Computer Science, 6971, 170-182
  • Semi-infinite programmingF Guerra Vazquez, JJ Rückmann In: J Cochran et al. (editors), Encyclopedia of Operations Research and ManagementScience, Wiley, Hoboken, 4770-4479
  • A Class of Methods Combining L-BFGS and Truncated NewtonFrimannslund, L., and Steihaug, T.In: Computer and Information Sciences II, pp. 565-570, Springer 

  • On a New Method for Derivative Free OptimizationFrimannslund, L., and Steihaug, T.International Journal On Advances in Software; Vol. 4(3-4) pp. 244-255


  • The variable radius covering problem with fuzzy travel timesS Davari, MHF Zarandi, A Hemmati, IB TurksenFuzzy Systems (FUZZ), 2010 IEEE International Conference on, 1-6    
  • Fuzzy time series based on defining interval length with Imperialist Competitive AlgorithmMHF Zarandi, A Molladavoudi, A HemmatiFuzzy Information Processing Society (NAFIPS), 2010 Annual Meeting of the North American    
  • Fuzzy Clustering for Initialization of Simulated Annealing Algorithm to Solve a Capacitated Vehicle Routing ProblemMHF Zarandi, S Davari, A HemmatiProceedings of the 2010 International Conference on Industrial Engineering and Operations Management 
  • Feasibility testing for dial-a-ride problemsD Haugland, SC HoLecture Notes in Computer Science, 6124, 170-179
  • An overview of models and solution methods for pooling problemsD HauglandIn E Bjørndal, M Bjørndal, PM Pardalos, M Rönnqvist (eds.): Energy, Natural Resources and Environmental Economics, 459-469, ISBN 978-3-642-12066-4, Springer
  • On interior logarithmic smoothing and strongly stable stationary points HT Jongen, JJ Rückmann SIAM J. Optimization 20 (5), 2137-2156

  • Joint routing, link scheduling and power control for wireless multi-hop networks for CDMA/TDMA systemsJJ Rückmann, M Sanchez Meraz, C Sosa PazCientifica 14 (4), 165-172

  • STA, The Space Trajectory Analysis Project - European Space Agency (ESA)G Ortega, S Erb, JJ Rückmann et al.Proceedings of the 4th International Conference on Astrodynamics Tools and Techniques, Madrid, Spain

  • Regression analysis for clusters in gene-environment networks based on ellipsoidal calculus and optimizationE Kropat, JJ Rückmann, GW Weber Dynamics of Continuous, Discrete and Impulsive Systems 17 (5), 639-657

  • A generic primal-dual interior-point method for semidefinite optimization based on a new class of kernel functionsEl Ghami, M., Roos, C., and Steihaug, T.Optimization Methods and Software; Vol. 25(3)  387-403 

  • On large-scale unconstrained optimization problems and higher order methodsGundersen, G. and Steihaug,T.Optimization Methods and Software; Vol. 25(3) s. 227-358

  • Kernel-function Based Primal-Dual Algorithms for P*(k) Linear Complementarity ProblemsEl Ghami, M., Steihaug, T.Reserche operationelle; Vol. 44(3) p. 185-205