Sigurður Freyr Hafstein (aka Marinoson), dr.rer.nat.
Sigurður Freyr Hafstein
dr. rer. nat.
Professor for Applied Mathematics
Faculty of Physical Sciences
Dunhagi 5
IS-107 Reykjavik
Iceland
Office: Tæknigarður Tg-328
Telephone: +354 696 6325
Email: shafstein@hi.is
Conference Organization:
SciCADE 2021/2022 University of Iceland
Research Areas: Dynamical systems, Stability in dynamical systems, Numerical methods, Lyapunov functions, Contraction metrics.
Rannsóknasvið: Hreyfikerfi, stöðugleiki hreyfikerfa, tölulegar aðferðir, Lyapunov-föll, herpifirðir.
PUBLICATIONS
Monograph, peer-reviewed:
S.F. Hafstein.
An algorithm for constructing Lyapunov functions.
Electronic Journal of Differential Equations, Monograph 08 (2007).
Journal Articles, peer-reviewed:
P. Giesl, S.F. Hafstein, and I. Mehrabinezhad.
Contraction Metric Computation using numerical Integration and Quadrature.
Discrete and Continuous Dynamical Systems – Series B, 29-6, (2024), pp. 2610-2632.
S.F. Hafstein.
Lyapunov Functions for Switched Linear Systems: Proof of Convergence for an LP Computational Approach.
IEEE Control System Letters, 7, (2023), pp. 3283-3288.- S. Hafstein and A. Tanwani
Linear Programming based Lower Bounds on Average Dwell-Time via Multiple Lyapunov Functions.
European Journal of Control, 74 (2023), Article 100838. J. Piccini, E. August, S.F. Hafstein, and S. Andersen.
Sufficient Stability Conditions for a Class of Switched Systems with Multiple Steady States.
IEEE Control System Letters, 7, (2023), pp. 2653 – 2658.P. Giesl and S.F. Hafstein.
Triangulations and Error Estimates for Interpolating Lyapunov Functions.
SN Computer Science, 4, (2023), Article 364.P. Giesl, S.F. Hafstein, M. Haraldsdottir, D. Thorsteinsson, and C. Kawan.
Subgradient algorithm for computing contraction metrics for equilibria.
Journal of Computational Mathematics, 10-2, (2023), pp. 281-303.P. Giesl, S.F. Hafstein, and C. Kawan.
Review on contraction analysis and computation of contraction metrics.
Journal of Computational Mathematics, 10-1, (2023), pp. 1-47.S. Andersen, P. Giesl, and S.F. Hafstein.
Common Lyapunov functions for switched linear systems: Linear Programming based approach.
IEEE Control System Letters, 7, (2023), pp. 901-906.M. Louzeiro, C. Kawan, S.F. Hafstein, P. Giesl, and J. Yuan.
A Projected Subgradient Method for the Computation of Adapted Metrics for Dynamical Systems.
SIAM Journal on Applied Dynamical Systems, 21-4, (2022), pp. 2610-2641.P. Giesl, S.F. Hafstein, and Stefan Suhr.
Existence of complete Lyapunov functions with prescribed orbital derivative.
Discrete and Continuous Dynamical Systems – Series B, 27-11, (2022), pp. 6927-6941.S.F. Hafstein and C. Kawan.
Corrigendum to „Numerical approximation of the data-rate limit for state estimation under communication constraints“.
Journal of Mathematical Analysis and Applications, 509-2, (2022), Article 125967.C. Argáez, P. Giesl, and S.F. Hafstein.
Eigenpairs for the Analysis of Complete Lyapunov Functions.
Complexity, 90-331, (2022), Article 3160052.P. Giesl, S.F. Hafstein, and I. Mehrabinezhad.
Robustness of Numerically Computed Contraction Metrics.
SN Computer Science, 3, (2022), Article 257.P. Giesl and S.F. Hafstein.
System specific triangulations for the construction of CPA Lyapunov functions.
Discrete and Continuous Dynamical Systems – Series B, 26-12, (2021), pp. 6027–6046.P. Giesl, C. Argáez, S.F. Hafstein, and H. Wendland.
Minimization with Differential Inequality Constraints applied to Complete Lyapunov Functions.
Mathematics of Computation, 90-331, (2021), pp. 2137-2160.C. Kawan, S.F. Hafstein, and P. Giesl.
ResEntSG: Restoration entropy estimation for dynamical systems via Riemannian metric optimization.
SoftwareX, 15, (2021), Article 100743.P. Giesl, S.F. Hafstein, and I. Mehrabinezhad.
Computation and verification of contraction metrics for periodic orbits.
Journal of Mathematical Analysis and Applications, 503-1, (2021), Article 125309.S.F. Hafstein and S. Suhr.
Smooth complete Lyapunov functions for ODEs.
Journal of Mathematical Analysis and Applications, 499-1, (2021), Article 125003.P. Giesl, S.F. Hafstein, and I. Mehrabinezhad.
Computation and verification of contraction metrics for exponentially stable equilibria.
Journal of Computational and Applied Mathematics, 390, (2021), Article 113332.P. Giesl, Z. Langhorne, C. Argáez, and S.F. Hafstein.
Computing complete Lyapunov functions for discrete-time dynamical systems.
Discrete and Continuous Dynamical Systems – Series B, 26-1, (2021), pp. 299-336.C. Argáez, P. Giesl, and S.F. Hafstein.
Update (2.0) to LyapXool: Eigenpairs and new classification methods.
SoftwareX, 12, (2020), Article 100616.P. Giesl, C. Osborne, and S.F. Hafstein.
Automatic Determination of Connected Sublevel Sets of CPA Lyapunov Functions .
SIAM Journal on Applied Dynamical Systems, 19-2, (2020), pp. 1029-1056.S. Albertsson, S.F. Hafstein, P. Giesl, and S. Gudmundsson.
Simplicial complex with approximate rotational symmetry: A general class of simplicial complexes.
Journal of Computational and Applied Mathematics, 363, (2020), pp. 413-425.C. Argáez, J.-C. Berthet, H. Björnsson, P. Giesl, and S.F. Hafstein.
LyapXool: a program to compute complete Lyapunov functions.
SoftwareX, 10, (2019), Article 100325.S.F. Hafstein and A. Valfells.
Efficient computation of Lyapunov functions for nonlinear systems by integrating numerical solutions.
Nonlinear Dynamics, 97-3, (2019), pp. 1895-1910.H. Bjornsson, S.F. Hafstein, P. Giesl, E. Scalas, and S. Gudmundsson.
Computation of the stochastic basin of attraction by rigorous construction of a Lyapunov function.
Discrete and Continuous Dynamical Systems – Series B, 24-8, (2019), pp. 4247-4269.S.F. Hafstein and C. Kawan.
Numerical approximation of the data-rate limit for state estimation under communication constraints.
Journal of Mathematical Analysis and Applications, 473-2, (2019), pp. 1280-1304.S. Gudmundsson and S.F. Hafstein.
Probabilistic Basin of Attraction and Its Estimation Using Two Lyapunov Functions.
Complexity, (2018), Article 2895658.S.F. Hafstein, S. Gudmundsson, P. Giesl, and E. Scalas.
Lyapunov function computation for autonomous linear stochastic differential equations using sum-of-squares programming.
Discrete and Continuous Dynamical Systems – Series B, 23-2, (2018), pp. 939-956.S.F. Hafstein and H. Li.
Computation of Lyapunov Functions for Nonautonomous Systems on Finite Time-Intervals by Linear Programming.
Journal of Mathematical Analysis and Applications, 447-2, (2017), pp. 933-950.P. Giesl and S.F. Hafstein.
Computation and Verification of Lyapunov Functions.
SIAM Journal on Applied Dynamical Systems, 14-4, (2015), pp. 1663-1698.H. Li, R. Baier, L. Grüne, S.F. Hafstein, and F. Wirth.
Computation of Local ISS Lyapunov Functions with Low Gains Via Linear Programming.
Discrete and Continuous Dynamical Systems – Series B, 20-6, (2015), pp. 2477-2495.H. Li, S.F. Hafstein, and C.M. Kellett.
Computation of continuous and piecewise affine Lyapunov functions for discrete-time systems.
Journal of Difference Equations and Applications, 21-6, (2015), pp. 486-511.S.F. Hafstein, C.M. Kellett, and H. Li.
Computing continuous and piecewise affine Lyapunov functions for nonlinear systems.
Journal of Computational Dynamics, 2-2, (2015), pp. 227 – 246.P. Giesl and S.F. Hafstein.
Review on computational methods for Lyapunov functions.
Discrete and Continuous Dynamical Systems – Series B, 20-8, (2015), pp. 2291-2331.J. Björnsson, P. Giesl, S.F. Hafstein, and C.M. Kellett.
Computation of Lyapunov functions for systems with multiple local attractors .
Discrete and Continuous Dynamical Systems – Series A, 35-9, (2015), pp. 4019-4039.P. Giesl and S.F. Hafstein.
Computation of Lyapunov functions for nonlinear discrete time systems by linear programming.
Journal of Difference Equations and Applications, 20-4, (2014), pp. 610-640.P. Giesl and S.F. Hafstein.
Revised CPA method to compute Lyapunov functions for nonlinear systems.
Journal of Mathematical Analysis and Applications, 410, (2014), pp. 292-306.P. Giesl and S.F. Hafstein.
Construction of a CPA contraction metric for periodic orbits using semidefinite optimization.
Nonlinear Analysis: Theory, Methods & Applications, 86, (2013), pp. 114-134.P. Giesl and S.F. Hafstein.
Existence of piecewise linear Lyapunov functions in arbitrary dimensions.
Discrete and Continuous Dynamical Systems – Series A, 32-10, (2012), pp. 3539-3565.P. Giesl and S.F. Hafstein.
Construction of Lyapunov functions for nonlinear planar systems by linear programming.
Journal of Mathematical Analysis and Applications, 388, (2012), pp. 463-479.R. Baier, L. Grüne, and S.F Hafstein.
Linear programming based Lyapunov function computation.
Discrete and Continuous Dynamical Systems – Series B, 17-1, (2012), pp. 33-56.A. Pedersen, S.F. Hafstein, and H. Jónsson.
Efficient Sampling of Saddle Points with the Minimum-Mode Following Method.
SIAM Journal of Scientific Computing, 33-2, (2011), pp. 633-652.P. Giesl and S.F. Hafstein.
Existence of piecewise affine Lyapunov functions in two dimensions.
Journal of Mathematical Analysis and Applications, 371-1, (2010), pp. 233-248.S.F. Hafstein.
A constructive converse Lyapunov theorem on asymptotic stability for nonlinear autonomous ordinary differential equations.
Dynamical Systems: An International Journal, 20-3, (2005), pp. 281-299.S.F. Hafstein.
Lyapunov-föll og reiknirit til smíði þeirra.
Tímarit um raunvísindi og stærðfræði, 2-2, (2004), pp. 117-130. (in Icelandic)R. Chrobok, A. Pottmeier, S.F. Hafstein, and M. Schreckenberg.
Traffic Forecast in Large Scale Freeway Networks.
International Journal of Bifurcation and Chaos 14-6 (2004), pp. 1995-2005.S.F. Hafstein, R. Chrobok, A. Pottmeier, M. Schreckenberg, and F. Mazur.
A High-Resolution Cellular Automata Traffic Simulation Model with Application
in a Freeway Traffic Information System.
Computer-Aided Civil and Infrastructure Engineering 19-5 (2004), pp. 338-350.S.F. Hafstein.
A constructive converse Lyapunov theorem on exponential stability.
Discrete and Continuous Dynamical Systems – Series A 10-3 (2004), pp. 657-678.F. Mazur and S.F. Hafstein.
Verkehrslage via Internet: autobahn.NRW.
Logistik Management 6-4 (2004), pp. 60-69. (in German)S.F. Marinosson.
Lyapunov function construction for ordinary differential equations with linear programming.
Dynamical Systems: An International Journal 17 (2002), pp. 137-150.T. Jonsson and S.F. Marinosson.
Scaling and correlation functions in a model of a two-dimensional earthquake fault.
Physica Scripta 58 (1998), pp. 282-288.T. Jonsson and S.F. Marinosson.
Correlation functions and power spectra in a model of an earthquake fault.
Physics Letters A 207 (1995), pp. 165-172.
Articles, not peer-reviewed:
P. Giesl and S.F. Hafstein.
Preface to Special Issue on „Computation of Lyapunov functions and contraction metrics“ .
Journal of Computational Mathematics, 10-1, (2023), pp. i-iv.S.F. Hafstein.
The Icelandic Mathematical Society.
EMS Newsletter (European Mathematical Society), 106, (2017), p. 32.P. Giesl and S.F. Hafstein.
Preface to Special Section on „Computational methods for Lyapunov functions“ .
Discrete and Continuous Dynamical Systems – Series B, 20-8, (2015), pp.i-ii.S.F. Hafstein.
Continuity of scalar-fields characterized by smooth paths fulfilling |s(t)||s'(t)|<+\infty.
arXiv:1302.3411v1 (2013).R. Chrobok, S.F. Hafstein, A. Pottmeier, and M. Schreckenberg.
Simulation des Autobahnverkehrs in NRW:
Aktuelle Verkehrslage und -prognose via Internet.
In: it_trends: potenziale der metropolregion ruhr, pp. 13-22, Projekt Ruhr, Essen (2004).
(in German)S.F. Hafstein.
A constructive converse Lyapunov theorem on asymptotically
stable differential equations’ equilibria.
The nonlinear autonomous case.
Schriftenreihe des Instituts für Mathematik, University Duisburg-Essen
SM-DU-576, (2004).G. Törner, O. Annen, and S.F. Marinosson.
Bestimmung optimaler Standorte
zur Erfassung von Verkehrsflüssen am Beispiel des Güterzugnetzes von DB Cargo.
OR-News 11 (2001), pp. 23-26.
(in German)
Book Chapters, peer-reviewed:
P. Giesl and S.F. Hafstein.
Lyapunov Functions by Interpolating Numerical Quadrature: Proof of Convergence.
In: Dynamical Systems in Theoretical Perspective
Series: Springer Proceedings in Mathematics and Statistics ?
ed. J. Awrejcewicz, Springer 2023. pp. .S.F. Hafstein.
Sliding Modes and Lyapunov Functions for Differential Inclusions by Linear Programming.
In: Informatics in Control, Automation and Robotics.
Series: Lecture Notes in Electrical Engineering 793
eds. O. Gusikhin, K. Madani, and J. Zaytoon, Springer 2022. pp. 1-23.H. Bjornsson and S.F. Hafstein.
Advanced algorithm for interpolation with Wendland functions.
In: Informatics in Control, Automation and Robotics.
Series: Lecture Notes in Electrical Engineering 720
eds. O. Gusikhin, K. Madani, and J. Zaytoon, Springer 2021. pp. 99-117.C. Argáez, P. Giesl, and S.F. Hafstein.
Complete Lyapunov Functions: Determination of the Chain-recurrent set using the Gradient.
In: Simulation and Modeling Methodologies, Technologies and Applications
Series: Advances in Intelligent Systems and Computing 1260
eds. M. Obaidat, T. Ören, and F. De Rango, Springer 2021. pp. 104-121.C. Argáez, P. Giesl, and S.F. Hafstein.
Iterative Construction of Complete Lyapunov Functions: Analysis of Algorithm Efficiency.
In: Simulation and Modeling Methodologies, Technologies and Applications
Series: Advances in Intelligent Systems and Computing 947
eds. M. Obaidat, T. Ören, and F. De Rango, Springer 2020. pp. 83-100.S.F. Hafstein.
Fast Algorithms for Computing Continuous Piecewise Affine Lyapunov Functions.
In: Simulation and Modeling Methodologies, Technologies and Applications
Series: Advances in Intelligent Systems and Computing 873
eds. M. Obaidat, T. Ören, and F. De Rango, Springer 2019. pp. 274-299.C. Argáez, P. Giesl, and S.F. Hafstein.
Complete Lyapunov Functions: Computation and Applications.
In: Simulation and Modeling Methodologies, Technologies and Applications
Series: Advances in Intelligent Systems and Computing 873
eds. M. Obaidat, T. Ören, and F. De Rango, Springer 2019. pp. 200-221.H. Bjornsson and S.F. Hafstein.
Lyapunov functions for almost sure exponential stability.
In: Dynamical Systems in Theoretical Perspective
Series: Springer Proceedings in Mathematics and Statistics 248
ed. J. Awrejcewicz, Springer 2018. pp. 51-61.C. Argáez, P. Giesl, and S.F. Hafstein.
Computational approach for complete Lyapunov functions.
In: Dynamical Systems in Theoretical Perspective
Series: Springer Proceedings in Mathematics and Statistics 248
ed. J. Awrejcewicz, Springer 2018. pp. 1-11.P. Giesl and S.F Hafstein.
Local Lyapunov Functions for periodic and finite-time ODEs.
In: Recent Trends in Dynamical Systems
Series: Springer Proceedings in Mathematics and Statistics
eds. A. Johann, H.Kruse, F. Rupp, and S. Schmitz, Springer 2013. pp. 125-152.R. Selten, M. Schreckenberg, T. Chmura, T. Pitz, S. Kube,
S.F. Hafstein, R. Chrobok, A. Pottmeier, and J. Wahle.
Experimental Investigation of Day-to-Day Route-Choice Behavior
and Network Simulations of Autobahn Traffic in North Rhine-Westphalia.
In: Human Behaviour and Traffic Networks,
eds. M. Schreckenberg and R. Selten,
Springer 2004, pp. 1-21.
(R. Selten received the Nobel-Prize in Economics 1994)
Conference Proceedings, peer-reviewed:
P. Giesl, S.F. Hafstein, and I. Mehrabinezhad.
Positively invariant Sets for ODEs and numerical Integration.
In: Proceedings of the 20th International Conference on Informatics in Control, Automation and Robotics (ICINCO),
Rom, Italy, 2023, pp. 44-53.P. Giesl, S.F. Hafstein, and I. Mehrabinezhad.
Contraction Metrics by Numerical Integration and Quadrature: Uniform Error Estimate.
In: Proceedings of the 20th International Conference on Informatics in Control, Automation and Robotics (ICINCO),
Rom, Italy, 2023, pp. 196-205.S. Andersdottir, E. August, S.F. Hafstein, and J. Piccini.
Lyapunov Function Computation for Linear Switched Systems: Comparison of SDP and LP Approaches.
In: Proceedings of the 13th International Conference on Simulation and Modeling Methodologies, Technologies and Applications (SIMULTECH),
Rom, Italy, 2023, pp. 61-70.S.F. Hafstein.
Efficient Verification of CPA Lyapunov Functions.
In: Proceedings of the 19th International Conference on Informatics in Control, Automation and Robotics (ICINCO),
Lisbon, Portugal, 2022, pp. 120-129.C. Argáez, P. Giesl, and S.F. Hafstein.
Statistical Analysis of an Iterative Algorithm Class for Dynamical Systems.
In: Advances in Nonlinear Dynamics.
Series: NODYCON Conference Proceedings
eds. W. Lacarbonara, B. Balachandran, M. Leamy, J. Ma, J. Tenreiro Machado, G. Stepan, Springer 2022. pp. 453-464.C. Argáez, P. Giesl, and S.F. Hafstein.
WendlandXool: Simplified C++ Code to Compute Wendland Functions.
In: Advances in Nonlinear Dynamics.
Series: NODYCON Conference Proceedings
eds. W. Lacarbonara, B. Balachandran, M. Leamy, J. Ma, J. Tenreiro Machado, G. Stepan, Springer 2022. pp. 465-474.P. Giesl, S.F. Hafstein, and I. Mehrabinezhad.
Computing Contraction Metrics for three-dimensional Systems.
IFAC PapersOnLine 54-9 (2021), pp. 297-303.P. Giesl, S.F. Hafstein, and I. Mehrabinezhad.
Computing Contraction Metrics: Comparison of Different Implementations.
IFAC PapersOnLine 54-9 (2021), pp. 310-316.P. Giesl, S.F. Hafstein, and I. Mehrabinezhad.
Robustness of Contraction Metrics Computed by Radial Basis Functions.
In: Proceedings of the 18th International Conference on Informatics in Control, Automation and Robotics (ICINCO),
Online (because of covid-19), 2021, pp. 592-599.P. Giesl and S.F. Hafstein.
Uniformly Regular Triangulations for Parameterizing Lyapunov Functions.
In: Proceedings of the 18th International Conference on Informatics in Control, Automation and Robotics (ICINCO),
Online (because of covid-19), 2021, pp. 549-557.C. Argáez, P. Giesl, and S.F. Hafstein.
Comparison of Different Radial Basis Functions in Dynamical Systems.
In: Proceedings of the 11th International Conference on Simulation and Modeling Methodologies, Technologies and Applications (SIMULTECH),
Online (because of covid-19), 2021, pp. 394-405.S.F. Hafstein.
CPA Lyapunov functions: Switched Systems vs. Differential Inclusions.
In: Proceedings of the 17th International Conference on Informatics in Control, Automation and Robotics (ICINCO),
Online (because of covid-19), 2020, pp. 745-753.C. Argáez, P. Giesl, and S.F. Hafstein.
Evaluation of Lyapunov Function Candidates Through Averaging Iterations.
In: Proceedings of the 17th International Conference on Informatics in Control, Automation and Robotics (ICINCO),
Online (because of covid-19), 2020, pp. 734-744.C. Argáez, P. Giesl, and S.F. Hafstein.
Critical tolerance evolution: Classification of the chain-recurrent set.
In:Proceedings of the 15th International Conference on Dynamical Systems: Theory and Applications (DSTA), Volume: Mathematical and Numerical Aspects of Dynamical System Analysis,
Lodz, Poland, 2019, pp. 21-32.S.F. Hafstein.
Numerical Analysis Project in ODEs for Undergraduate Students.
In: Computational Science – ICCS 2019
19th International Conference, Faro, Portugal, June 12-14, 2019, Proceedings, Part V
Series: Lecture Notes in Computer Science 11540
eds. J. Rodrigues, P. Cardoso, J. Monteiro, R. Lam, V. Krzhizhanovskaya, M. Lees, J. Dongarra, and P. Sloot
Springer 2019. pp. 421-434.C. Argáez, P. Giesl, and S.F. Hafstein.
Middle Point Reduction of the Chain-recurrent Set.
In: Proceedings of the 9th International Conference on Simulation and Modeling Methodologies, Technologies and Applications (SIMULTECH),
Prague, Czech Republic, 2019, pp. 141-152.C. Argáez, P. Giesl, and S.F. Hafstein.
Clustering Algorithm for Generalized Recurrences using Complete Lyapunov Functions.
In: Proceedings of the 16th International Conference on Informatics in Control, Automation and Robotics (ICINCO),
Prague, Czech Republic, 2019, pp. 138-146.H. Bjornsson and S.F. Hafstein.
Algorithm and Software to Generate Code for Wendland Functions in Factorized Form.
In: Proceedings of the 16th International Conference on Informatics in Control, Automation and Robotics (ICINCO),
Prague, Czech Republic, 2019, pp. 156-162.S.F. Hafstein.
Lyapunov Functions for Linear Stochastic Differential Equations: BMI Formulation of the Conditions.
In: Proceedings of the 16th International Conference on Informatics in Control, Automation and Robotics (ICINCO),
Prague, Czech Republic, 2019, pp. 147-155.S.F. Hafstein.
Numerical ODE Solvers and Integration Methods in the Computation of CPA Lyapunov Functions.
In: Proceedings of the 18th European Control Conference (ECC),
Napoli, Italy, 2019, pp. 1136-1141.C. Argáez, P. Giesl, and S.F. Hafstein.
Improved estimation of the chain-recurrent set.
In: Proceedings of the 18th European Control Conference (ECC),
Napoli, Italy, 2019, pp. 1622-1627.S.F. Hafstein.
Common Lyapunov function computation for discrete-time systems.
In: Proceedings of the 57rd IEEE Conference on Decision and Control (CDC),
Miami Beach, FL, USA, 2018, pp. 3211-3216.C. Argáez, P. Giesl, and S.F. Hafstein.
Computation of Complete Lyapunov Functions for Three-Dimensional Systems.
In: Proceedings of the 57rd IEEE Conference on Decision and Control (CDC),
Miami Beach, FL, USA, 2018, pp. 4059-4064.C. Argáez, P. Giesl, and S.F. Hafstein.
Iterative Construction of Complete Lyapunov Functions.
In: Proceedings of the 8th International Conference on Simulation and Modeling Methodologies, Technologies and Applications (SIMULTECH),
Porto, Portugal, 2018, pp. 211-222.H. Bjornsson and S.F. Hafstein.
Verification of a Numerical Solution to a Collocation Problem.
In Proceedings of the 15th International Conference on Informatics in Control, Automation and Robotics (ICINCO),
Porto, Portugal, 2018, pp. 587-594.P. Giesl, C. Argáez, S.F. Hafstein, and H. Wendland.
Construction of a Complete Lyapunov Function using Quadratic Programming.
In Proceedings of the 15th International Conference on Informatics in Control, Automation and Robotics (ICINCO),
Porto, Portugal, 2018, pp. 560-568.H. Bjornsson, P. Giesl, S. Gudmundsson, and S.F. Hafstein.
Local Lyapunov Functions for Nonlinear Stochastic Differential Equations by Linearization.
In Proceedings of the 15th International Conference on Informatics in Control, Automation and Robotics (ICINCO),
Porto, Portugal, 2018, pp. 579-586.S. Hafstein and A. Valfells.
Study of dynamical systems by fast numerical computation of Lyapunov functions.
In: Proceedings of the 14th International Conference on Dynamical Systems: Theory and Applications (DSTA),
Volume: Mathematical and Numerical Aspects of Dynamical System Analysis
Lodz, Poland, 2017, pp. 229-240.S. Hafstein.
Efficient Algorithms for Simplicial Complexes Used in the Computation of Lyapunov Functions for Nonlinear Systems.
In: Proceedings of the 7th International Conference on Simulation and Modeling Methodologies, Technologies and Applications (SIMULTECH),
Madrid, Spain, 2017, pp. 398-409.C. Argáez, S. Hafstein, and P. Giesl.
Wendland Functions: A C++ Code to Compute Them.
In: Proceedings of the 7th International Conference on Simulation and Modeling Methodologies, Technologies and Applications (SIMULTECH),
Madrid, Spain, 2017, pp. 323-330.C. Argáez, P. Giesl, and S. Hafstein.
Analysing Dynamical Systems: Towards Computing Complete Lyapunov Functions.
In: Proceedings of the 7th International Conference on Simulation and Modeling Methodologies, Technologies and Applications (SIMULTECH),
Madrid, Spain, 2017, pp. 134-144.J. Björnsson and S. Hafstein.
Efficient Lyapunov Function computation for systems with multiple exponentially stable equilibria.
Procedia Computer Science 108 (2017), pp. 655-664
Proceedings of the International Conference on Computational Science (ICCS), Zurich, Switzerland, 2017.J. Björnsson, S. Gudmundsson and S. Hafstein.
Class library in C++ to compute Lyapunov functions for nonlinear systems.
In: Proceedings of the 1st Conference on Modelling, Identification and Control of Nonlinear Systems (MICNON),
Saint-Petersburg, Russia, 2015, no. 0155, pp. 788-793.
C++ library and programs discussed paper.S. Gudmundsson and S. Hafstein.
Lyapunov Function Verification: MATLAB Implementation.
In: Proceedings of the 1st Conference on Modelling, Identification and Control of Nonlinear Systems (MICNON),
Saint-Petersburg, Russia, 2015, no. 0235, pp. 806-811.
Matlab programs used in paper.H. Li, S. Hafstein, and C. Kellett.
Computation of Lyapunov Functions for Discrete-Time Systems using the Yoshizawa Construction.
In: Proceedings of the 53rd IEEE Conference on Decision and Control (CDC),
Los Angeles, CA, USA, 2014, pp. 5512-5517.J. Björnsson, P. Giesl, S. Hafstein, C. Kellett, and H. Li.
Computation of continuous and piecewise affine Lyapunov functions by numerical approximations of the Massera construction.
In: Proceedings of the 53rd IEEE Conference on Decision and Control (CDC),
Los Angeles, CA, USA, 2014, pp. 5506-5511.R. Baier and S.F. Hafstein.
Numerical Computation of Control Lyapunov Functions in the Sense of Generalized Gradients.
In: Proceedings of the 21st International Symposium on Mathematical Theory of Networks and Systems (MTNS),
Groningen, The Netherlands, 2014, no. 0232, pp. 1173-1180.J. Björnsson, P. Giesl, and S. Hafstein.
Algorithmic verification of approximations to complete Lyapunov functions.
In: Proceedings of the 21st International Symposium on Mathematical Theory of Networks and Systems (MTNS),
Groningen, The Netherlands, 2014, no. 0180, pp. 1181-1188.H. Li, R. Baier, L. Grüne, S.F. Hafstein, and F. Wirth.
Computation of Local ISS Lyapunov Functions Via Linear Programming.
In: Proceedings of the 21st International Symposium on Mathematical Theory of Networks and Systems (MTNS),
Groningen, The Netherlands, 2014, no. 0158, pp. 1189-1195.S. Hafstein, C.M. Kellett, and H. Li.
Continuous and Piecewise Affine Lyapunov Functions using the Yoshizawa Construction.
In: Proceedings of the 2014 American Control Conference (ACC),
Portland (OR), USA, 2014, no. 0170, pp. 548-553.P. Giesl and S. Hafstein.
Implementation of a Fan-Like Triangulation for the CPA Method to compute Lyapunov Functions.
In: Proceedings of the 2014 American Control Conference (ACC),
Portland (OR), USA, 2014, no. 0202, pp. 2989-2994.S.F. Hafstein.
Implementation of Simplicial Complexes for CPA functions in C++11 using the Armadillo Linear Algebra Library.
In: Proceedings of 4th International Conference on Simulation and Modeling Methodologies, Technologies and Applications (SIMULTECH),
Reykjavik, Iceland, 2013, pp. 49-57.R. Baier, L. Grüne, and S.F. Hafstein.
Computing Lyapunov functions for strongly asymptotically stable differential inclusions.
In: Proceedings of NOLCOS 2010,
Bologna, Italy, 2010.D. Weber, R. Chrobok, S. Hafstein, F. Mazur, A. Pottmeier, and M. Schreckenberg.
OLSIM: Inter-urban Traffic Information.
In: Innovative Internet Community Systems: 4th International Workshop,
Guadalajara, Mexico, 2004, pp. 296-306.F. Mazur, R. Chrobok, S.F. Hafstein, A. Pottmeier, and M. Schreckenberg.
Future of Traffic Information – Online-Simulation of a Large Scale Freeway Network.
In: IADIS International Conference WWW/Internet 2004, Proceedings Volume 1.
Madrid, Spain, October 2004, pp. 665-672.F. Mazur, R. Chrobok, S.F. Hafstein, A. Pottmeier, and M. Schreckenberg.
Online-Simulation North Rhine-Westphalia – Traffic Information in a Large Scale Freeway Network.
In: 2nd Conference of the Euro-regional Projects (i2tern),
Intelligent Infrastructure for the Trans-European Road Network,
Vienna, Austria, 2004, pp. 140-144.R. Chrobok, S.F. Hafstein, A. Pottmeier, and M. Schreckenberg.
OLSIM: Future Traffic Information.
In: Proceedings of the IASTED International Conference,
Applied Simulation and Modelling.
Rhodes, Greece, 2004, doc. nr. 443-142 on CD.A. Pottmeier, S.F. Hafstein, R. Chrobok, J. Wahle, and M. Schreckenberg.
The Traffic State of the Autobahn Network of North Rhine-Westphalia:
An Online Traffic Simulation.
In: Proceedings of the 10th World Congress and Exhibition on
Intelligent Transport Systems and Services,
Solutions for Today… and Tomorrow,
Madrid, Spain, 2003, doc. nr. 2377 on CD.M. Schreckenberg, R. Chrobok, S.F. Hafstein, and A. Pottmeier.
OLSIM – Traffic Forecast and Planning using Simulations.
In: SCS/ASIM – 17. Symposium in Magdeburg, Simulationstechnik,
ed. R. Hohmann,
Magdeburg, Germany, 2003, pp. 11-18.S.F. Hafstein, R. Chrobok, A. Pottmeier, J. Wahle, and M. Schreckenberg.
Cellular Automaton Modeling of the Autobahn Traffic in North Rhine – Westphalia.
In: Proceedings of the 4-th MATHMOD Vienna, 4-th IMCAS Symposium on
Mathematical Modelling, ARGESIM Report no. 24,
ed. I. Troch and F. Breitenecker,
Vienna, Austria, 2003, pp. 1322-1331.S.F. Marinosson, R. Chrobok, A. Pottmeier, J. Wahle, and M. Schreckenberg.
Simulation Framework for the Autobahn Traffic in North Rhine-Westphalia.
In: Cellular Automata, proceedings of ACRI 2002, the 5th International
Conference on Cellular Automata for Research and Industry,
ed. S. Bandini, B. Chopard and M. Tomassini,
Geneve, Switzerland, 2002, pp. 315-324.S.F. Marinosson, R. Chrobok, A. Pottmeier, J. Wahle, and M. Schreckenberg.
Simulation des Autobahnverkehrs in NRW.
In: SCS/ASIM – 16. Symposium in Rostock,
Simulationstechnik,
ed. D. Tavangarian and R. Grützner,
Rostock, Germany, 2002, pp. 517-523.
(in German)J. Wahle, R. Chrobok, A. Pottmeier, S.F. Marinosson, and M. Schreckenberg.
An Online Simulation for the Freeway Network of
North Rhine-Westphalia Based on Real-World Traffic Data
In: GI-Technologien für Verkehr und Logistik, IfGI-Prints 13,
ed. J. Möltgen and A. Wytzisk,
Münster, Germany, 2002, pp. 193-210.R. Chrobok, A. Pottmeier, S.F. Marinosson, and M. Schreckenberg.
On-Line Simulation and Traffic Forecast: Applications and Results.
In: 6th IASTED International Conference,
Internet and Multimedia Systems and Applications,
ed. M. H. Hamza,
Kaua’i, Hawaii, USA, 2002, pp. 113-118.O.v. Laak, S.F. Marinosson, T. Möllers, and H.J. Wenz.
Control of a Chemical Process by Multi Regional State Space Systems.
In: Proceedings of the European Control Conference 1999, f1020-5, Karlsruhe, Germany.O.v. Laak, S.F. Marinosson, T. Möllers, and H.J. Wenz.
Stability of Fuzzy Systems based on an Approximation Argument.
In: Proceedings of EUFIT 1999, AC1-1, Aachen, Germany.
S.F. Marinosson.
Stability Analysis of Nonlinear Systems with Linear Programming:
A Lyapunov Functions Based Approach.
Doctoral Thesis, Gerhard-Mercator-University Duisburg (2002), Duisburg, Germany.S.F. Marinosson.
The Mathematics of Turbulence.
Diploma Thesis, Gerhard-Mercator-University Duisburg (1998), Duisburg, Germany.
- Hlynur Arnórsson, Ingunn Gunnarsdóttir og Sigurður Hafstein
Kennlusbók í stærðfærðigreiningu
ISBN 978-9935-24-309-6, 242 bls. 2017. - Ingunn Gunnarsdóttir og Sigurður Hafstein
Kennslubók í stærðfræðigreiningu í mörgum breytistærðum
ISBN 978-9935-24-686-8, 249 bls., 2020.
