Dr Björn Rüffer

Dr Björn Rüffer

Senior Lecturer

School of Information and Physical Sciences (Mathematics)

Career Summary


Dr Rüffer received the MSc (w/ distinction) in mathematics degree from
the University of Warwick, UK, in 2004, and the Dr. rer. nat. (PhD)
degree in mathematics from the University of Bremen, Germany, in 2007.

After a sequence of post-doctoral appointments at the University of
Newcastle (2007-2009), the University of Melbourne (2009-2011), and
the University of Paderborn (2011-2015), he re-joined the University
of Newcastle in 2015. He has held visiting positions at the Kyushu
Institute of Technology, Japan, the University of Passau, Germany, and
the University of British Columbia, Canada.

To the research community Dr Rüffer contributes as a referee for a
number of scientific journals and conferences, as an organiser of
scientific conferences, as associate editor for two flagship journals,
and as reviewer for a several research funding bodies. At
the University of Newcastle he has served as a member of the Academic
Senate and a member of the Faculty Board of the Faculty of Science
(both 2016-2017).


  • PhD, University of Bremen - Germany
  • Master of Science, University of Warwick - England


  • Difference and functional equations
  • Optimisation
  • Ordinary differential equations
  • Systems theory and control

Fields of Research

Code Description Percentage
490103 Calculus of variations, mathematical aspects of systems theory and control theory 20
490105 Dynamical systems in applications 10
490409 Ordinary differential equations, difference equations and dynamical systems 70

Professional Experience

Academic appointment

Dates Title Organisation / Department
28/4/2018 - 28/6/2018 Visiting Professor University of British Columbia
1/4/2014 - 1/9/2014 Visiting Professor University of Passau
Faculty of Computer Science and Mathematics


Dates Title Organisation / Department
15/5/2018 -  Associate Editor Automatica J. IFAC
1/1/2016 -  Member, SIAM Society for Industrial and Applied Mathematics (SIAM)
United States
1/1/2010 -  Associate Editor Systems & Control Letters
1/1/2008 -  Senior Member, IEEE Institute of Electrical and Electronics Engineers
United States



Year Award
2018 Outstanding reviewer for 2016-2017
Automatica J. IFAC

Research Award

Year Award
2012 Premium Award (best paper)

Teaching Award

Year Award
2020 Faculty of Science Teaching Excellence Award
Faculty of Science | University of Newcastle


Code Course Role Duration
MATH1110 Mathematics for Engineering, Science and Technology 1
The University of Newcastle, Australia
Coordinator and sole lecturer 22/2/2021 - 18/6/2021
STAT3800 Deterministic and Stochastic Optimisation
The University of Newcastle, Australia
Lecturer 22/2/2021 - 18/6/2021


For publications that are currently unpublished or in-press, details are shown in italics.

Journal article (18 outputs)

Year Citation Altmetrics Link
2019 Giladi O, Rüffer BS, 'A Perron Frobenius type result for integer maps and applications', Positivity, 23 545-570 (2019) [C1]
DOI 10.1007/s11117-018-0624-z
Co-authors Ohad Giladi
2019 Guiver C, Logemann H, Rüffer B, 'Small-gain stability theorems for positive Lur e inclusions', Positivity, 23 249-289 (2019) [C1]
DOI 10.1007/s11117-018-0605-2
Citations Scopus - 2
2019 Tran DN, Ruffer BS, Kellett CM, 'Convergence Properties for Discrete-time Nonlinear Systems', IEEE Transactions on Automatic Control, 64 3415-3422 (2019) [C1]
DOI 10.1109/TAC.2018.2879951
Citations Scopus - 4Web of Science - 4
Co-authors Chris Kellett
2018 Noroozi N, Geiselhart R, Gruene L, Ruffer BS, Wirth FR, 'Nonconservative Discrete-Time ISS Small-Gain Conditions for Closed Sets', IEEE TRANSACTIONS ON AUTOMATIC CONTROL, 63 1231-1242 (2018) [C1]
DOI 10.1109/TAC.2017.2735194
Citations Scopus - 13Web of Science - 11
2018 Giladi O, Rüffer BS, 'A Lyapunov Function Construction for a Non-convex Douglas-Rachford Iteration', Journal of Optimization Theory and Applications, 180 729-750 (2018) [C1]
DOI 10.1007/s10957-018-1405-3
Co-authors Ohad Giladi
DOI 10.3934/dcdsb.2015.20.2497
Citations Scopus - 44Web of Science - 36
2014 Rüffer BS, 'Input-to-state stability for discrete-time monotone systems', Proceedings of the 21st International Symposium on Mathematics Theory of Networks and Systems (MTNS), 96-102 (2014)
2013 Ruffer BS, Van De Wouw N, Mueller M, 'Convergent systems vs. incremental stability', Systems and Control Letters, 62 277-285 (2013) [C1]
DOI 10.1016/j.sysconle.2012.11.015
Citations Scopus - 50Web of Science - 46
2013 Ito H, Jiang Z-P, Dashkovskiy SN, Rüffer BS, 'Robust stability of networks of iISS systems: Construction of sum-type Lyapunov functions', IEEE Transactions on Automatic Control, 58 1192-1207 (2013) [C1]
DOI 10.1109/TAC.2012.2231552
Citations Scopus - 59Web of Science - 48
2011 Rüffer BS, Wirth FR, 'Stability verification for monotone systems using homotopy algorithms', Numerical Algorithms, 58 529-543 (2011) [C1]

A monotone self-mapping of the nonnegative orthant induces a monotone discrete-time dynamical system which evolves on the same orthant. If with respect to this system the origin i... [more]

A monotone self-mapping of the nonnegative orthant induces a monotone discrete-time dynamical system which evolves on the same orthant. If with respect to this system the origin is attractive then there must exist points whose image under the monotone map is strictly smaller than the original point, in the component-wise partial ordering. Here it is shown how such points can be found numerically, leading to a recipe to compute order intervals that are contained in the region of attraction and where the monotone map acts essentially as a contraction. An important application is the numerical verification of so-called generalized small-gain conditions that appear in the stability theory of large-scale systems. © 2011 Springer Science+Business Media, LLC.

DOI 10.1007/s11075-011-9468-3
Citations Scopus - 8Web of Science - 6
2010 Rüffer BS, Kellett CM, Dower PM, Weller SR, 'Belief propagation as a dynamical system: The linear case and open problems', IET Control Theory and Applications, 4 1188-1200 (2010) [C1]
DOI 10.1049/iet-cta.2009.0233
Citations Scopus - 11Web of Science - 10
Co-authors Chris Kellett, Steven Weller
2010 Ruffer BS, Sailer R, Wirth FR, 'Comments on "A Multichannel IOS Small Gain Theorem for Systems With Multiple Time-Varying Communication Delays', IEEE Transactions on Automatic Control, 55 1722-1725 (2010)
DOI 10.1109/tac.2010.2048938
Citations Scopus - 5Web of Science - 5
2010 Dashkovskiy SN, Ruffer BS, 'Local ISS of large-scale interconnections and estimates for stability regions', Systems and Control Letters, 59 241-247 (2010)
DOI 10.1016/j.sysconle.2010.02.001
Citations Scopus - 32Web of Science - 26
2010 Dashkovskiy SN, Ruffer BS, Wirth FR, 'Small gain theorems for large scale systems and construction of ISS Lyapunov functions', SIAM Journal on Control and Optimization, 48 4089-4118 (2010)
DOI 10.1137/090746483
Citations Scopus - 246Web of Science - 211
2010 Ruffer BS, Kellett CM, Weller SR, 'Connection between cooperative positive systems and integral input-to-state stability of large-scale systems', Automatica, 46 1019-1027 (2010) [C1]
DOI 10.1016/j.automatica.2010.03.012
Citations Scopus - 50Web of Science - 44
Co-authors Steven Weller, Chris Kellett
2010 Rüffer BS, 'Small-Gain Conditions and the Comparison Principle', IEEE TRANSACTIONS ON AUTOMATIC CONTROL, 55 1732-1736 (2010)
DOI 10.1109/TAC.2010.2048053
Citations Scopus - 21Web of Science - 19
2010 Ruffer BS, 'Monotone inequalities, dynamical systems, and paths in the positive orthant of Euclidean n-space', Positivity, 14 257-283 (2010) [C1]
DOI 10.1007/s11117-009-0016-5
Citations Scopus - 54Web of Science - 45
2007 Dashkovskiy S, Ruffer BS, Wirth FR, 'An ISS small gain theorem for general networks', Mathematics of Control, Signals, and Systems, 19 93-122 (2007)
DOI 10.1007/s00498-007-0014-8
Citations Scopus - 265Web of Science - 235
Show 15 more journal articles

Conference (1 outputs)

Year Citation Altmetrics Link
2019 Ito H, Rüffer BS, 'A Left Eigenvector Producing a Smooth Lyapunov Function of ISS Networks', Positive Systems. Theory and Applications (POSTA 2018). Lecture Notes in Control and Information Sciences, Hangzhou, China (2019) [E1]
DOI 10.1007/978-3-030-04327-8_20
Citations Scopus - 2

Grants and Funding


Number of grants 1
Total funding $442,830

Click on a grant title below to expand the full details for that specific grant.

20161 grants / $442,830

Activating Lyapunov-Based Feedback - Nonsmooth Control Lyapunov Functions$442,830

Funding body: ARC (Australian Research Council)

Funding body ARC (Australian Research Council)
Project Team Professor Christopher Kellett, Prof Dr Lars Gruene, Doctor Bjoern Rueffer, Dr Sigurdur Hafstein
Scheme Discovery Projects
Role Investigator
Funding Start 2016
Funding Finish 2018
GNo G1500106
Type Of Funding C1200 - Aust Competitive - ARC
Category 1200

Research Supervision

Number of supervisions


Past Supervision

Year Level of Study Research Title Program Supervisor Type
2019 PhD A Post-Keynesian SFC Model of GFC and Secular Stagnation Economics, Faculty of Business and Law, The University of Newcastle Co-Supervisor
2019 PhD Advances in Stability Analysis for Nonlinear Discrete-Time Dynamical Systems PhD (Electrical Engineering), College of Engineering, Science and Environment, The University of Newcastle Co-Supervisor

Research Collaborations

The map is a representation of a researchers co-authorship with collaborators across the globe. The map displays the number of publications against a country, where there is at least one co-author based in that country. Data is sourced from the University of Newcastle research publication management system (NURO) and may not fully represent the authors complete body of work.

Country Count of Publications
Germany 27
Australia 21
Japan 9
Netherlands 4
United States 4

Dr Björn Rüffer


Senior Lecturer
Mathematical Systems Theory & Optimisation
School of Information and Physical Sciences
College of Engineering, Science and Environment

Focus area


Contact Details

Email bjorn.ruffer@newcastle.edu.au
Phone (02) 491 38169
Links Personal webpage
Research Networks


Room SR213
Building SR Building
Location Callaghan
University Drive
Callaghan, NSW 2308