Prof. Dr. Julio RODRIGUEZ

Contact

Berner Fachhochschule
School of Engineering and Computer Science
Abt MNG Allgemeinbildung
Quellgasse 21
2501 Biel
Switzerland

Office: O 2

Email: julio.rodriguez (---[ a ... uNoWatt ... t ]---) bfh.ch

Telephone: +41 32 321 62 67





Biography and Current Work

In 2007, I received my master's in mathematics from the University of Geneva under the supervision of Professor GANDER (Section of Mathematics) and Professor GILLI (Department of Econometrics). In 2011, I completed my Ph.D. in applied mathematics from the EPFL School of Manufacturing Systems and Robotics, under the supervision of Professor HONGLER. In 2013, I completed a second Ph.D. thesis in theoretical physics at the University of Bielefeld, under the supervision of Professor BLANCHARD.

In 2020, I received a professorship in mathematics at the Bern University of Applied Sciences (Berner Fachhochschule - BFH), where I am currently teaching in the Deparment of Engineering and Computer Science. I also continue to work part-time as a senior specialist in energy data for Swissgrid AG, which I joined in 2015.

My research is centered on nonlinear dynamical systems and stochastic processes. In particular, my activities focus on networks of coupled limit cycle oscillators, synchronization, adaptive mechanisms, delayed differential equations and noise induced patterns in oscillatory networks, as well as chaotic behavior in dynamical systems. In a nutshell, the main topic of my research is summarised in the following animation:


Left, under SYNCHRONIZATION, you see seven oscillators, initially uncoupled (i.e. no black lines showing the network's interactions), each with its own frequency. When the network's interactions are introduced (i.e. black lines appearing in the animation), all oscillators synchronize (converge to a common frequency). However, as soon as the network interactions are removed, all oscillators go back to their own frequency. On the left, under ADAPTATION, you see the same set up, but here the oscillators are equipped with an adaptive frequency mechanism. Once they interact through the network, not only do they fully synchronise (to a common frequency and the same phase), they adapt to one another: when the network's interactions are removed, all oscillators continue to oscillate with the consensual frequency.

In a recent collaboration with Professor HONGLER, we revisited the dynamics of the Bouasse-Sarda "tournebroche", studied by Yves ROCARD in his 1943 contribution entitled Dynamique Général des Vibrations, and showed it exhibits chaotic evolution. The Bouasse-Sarda device, sketched by Yves ROCARD, is shown here bellow (left) and the corresponding equations of the dynamical system (right)


$$ \Large{ \begin{array}{rcl} (\mathsf{I} + m\rho^{2}) \ddot{\theta} + h \dot{\theta} & = & mg \rho + \mathsf{K} ( x - a \sin(\theta) ) a\cos(\theta) \\ & & \\ \mathsf{M} \ddot{x} + f \dot{x} & = & \mathsf{M}g - \mathsf{K} ( x - a \sin(\theta) ) \end{array} } $$ 9 control parameters:

- drum: radius \( \rho \), inertial moment \( \mathsf{I} \), suspended mass \( m \), friction \( h \)

- spring: stiffness coefficient \( \mathsf{K} \), suspended mass \( \mathsf{M} \), gravitation acceleration \( g \), friction \( f \)

- rotating spit: crank/handel radius \( a \)


Below are four animations (for four different values of \( a \)) showing period-doubling bifurcations. The values for the 9 control parameters are:

- drum: radius \( \rho = 0.1 \) [m], inertial moment \( \mathsf{I} = 9.24 \times 10^{-5} \) [kg][m]\(^2\), suspended mass \( m = 0.5 \) [kg], friction \( h = 0.03 \)

- spring: stiffness coefficient \( \mathsf{K} = 25 \) [N]/[m], suspended mass \( \mathsf{M} = 0.5 \) [kg], gravitation acceleration \( g = 9.8 \) [m]/[s]\(^2\), friction \( f = 0.02 \)

- rotating spit: crank/handel radius \( a \in \{0.05, 0.07, 0.075, 0.08\} \) [m]


For another set of parmeter values, on can clearly see the nowadays classic Feignebaum’s cascade of period-doubling bifurcations. The values for the 9 control parameters are:

- drum: radius \( \rho = 0.016 \) [m], inertial moment \( \mathsf{I} = 0.0001\) [kg][m]\(^2\), suspended mass \( m = 0.1 \) [kg], friction \( h = 0\) (as in Y. ROCARD's book)

- spring: stiffness coefficient \( \mathsf{K} = 2.5 \) [N]/[m], suspended mass \( \mathsf{M} = 0.03 \) [kg], gravitation acceleration \( g = 1.625 \) [m]/[s]\(^2\) (\( \dots\) on the moon!), friction \( f = 0.2 \)

- rotating spit: crank/handel radius \( a \in [0.04,0.0424] \) [m]





Publications

Articles and Book Chapters

RODRIGUEZ, J.   Network of adaptive frequency oscillators in a ballistic, non-Gaussian, noisy environment. To appear in: ISTE-Wiley book on Data Analysis, 2023.

RODRIGUEZ, J., HONGLER, M.-O.   Comme une bouteille à la mer... échouée au bord du Léman. In Yves Rocard, Portrait d'un grand physicien oublié, J.-M. GINOUX, F. JOVANOVIC. Hermann, 2023, 129-145.

RODRIGUEZ, J., HONGLER, M.-O.   How Chaotic Dynamics Drive a Vintage Grill-Room Spit. In 13th Chaotic Modeling and Simulation International Conference, C. H. SKIADAS, Y. DIMOTIKALIS (Editors). Springer International Publishing, 2021, 695-720.

RODRIGUEZ, J.   Adaptation of Oscillatory Systems in Networks - A Learning Signal Approach. Системні дослідження та інформаційні технології (System Research and Information Technologies), 2 (2014), 53-67. [link to .pdf file]

RODRIGUEZ, J.   Random Parametric Resonance in Time-Dependent Networks of Adaptive Frequency Oscillators. Discontinuity, Nonlinearity, and Complexity, 3 (3) (2014), 347-365, doi: 10.5890/DNC.2014.09.009.

RODRIGUEZ, J., HONGLER, M.-O., BLANCHARD, Ph.   Self-Shaping Attractors for Coupled Limit Cycle Oscillators. In Selected Topics in Nonlinear Dynamics and Theoretical Electrical Engineering, K. KYAMAKYA, W. A. HALANG, W. MATHIS, J. C. CHEDJOU, Z. LI (Editors). Springer (Berlin Heidelberg), 2013, 97-115.

HONGLER, M.-O., FILLIGER, R., BLANCHARD, Ph., RODRIGUEZ, J.   On Stochastic Processes Driven By Ballistic Noise Sources. In Contemporary Topics in Mathematics and Statistics with Applications, A. ADHIKARI, M. R. ADHIKARI, Y. P. CHAUBEY (Editors). Asian Books Private (New Delhi), 2013, 1-29.

RODRIGUEZ, J., HONGLER, M.-O., BLANCHARD, Ph.   Time-Delayed Interactions in Networks of Self-Adapting Hopf Oscillators. ISRN Mathematical Analysis, (2013), 9 pages, Article ID 816353, doi: 10.1155/2013/816353. [link to .pdf file]

RODRIGUEZ, J., HONGLER, M.-O.   Networks of Self-Adaptive Dynamical Systems. IMA Journal of Applied Mathematics, (2012), doi: 10.1093/imamat/hxs057.

RODRIGUEZ, J., HONGLER, M.-O.   Networks of Limit Cycle Oscillators with Parametric Learning Capability. In Recent Advances in Nonlinear Dynamics and Synchronization: Theory and Applications, K. KYAMAKYA, W. A. HALANG, H. UNGER, J. C. CHEDJOU, N. F. RULKOV, Z. LI (Editors). Springer (Berlin Heidelberg), 2009, 17-48.

RODRIGUEZ, J., HONGLER, M.-O.   Networks of Mixed Canonical-Dissipative Systems and Dynamic Hebbian Learning. International Journal of Computational Intelligence Systems, 2 (2009), 140-146.

International Conference and Workshop Proceedings

HONGLER, M.-O., FILLIGER, R., BLANCHARD, Ph., RODRIGUEZ, J.   On stochastic processes driven by ballistic noise sources. In Proceedings of MSAST 2011 - Mathematical Sciences for Advancement of Science and Technology, 2011.

RODRIGUEZ, J., HONGLER, M.-O., BLANCHARD, Ph.   Self-Adaptive Attractor-Shaping for Oscillators Networks. In Proceedings of The Joint INDS'11 & ISTET'11 - Third International Workshop on nonlinear Dynamics and Synchronization and Sixteenth International Symposium on Theoretical Electrical Engineering, 2011.

RODRIGUEZ, J., HONGLER, M.-O.   Parametric Resonance in Time-Dependent Networks of Hopf Oscillators. In Proceedings of ECCS'10 - European Conference on Complex Systems, 2010.

HONGLER, M.-O., FILLIGER, R., BLANCHARD, Ph., RODRIGUEZ, J.   Noise Induced Temporal Patterns in Populations of Globally Coupled Oscillators. In Proceedings of INDS'09 - Second International Workshop on Nonlinear Dynamics and Synchronization, 2009.

RODRIGUEZ, J., HONGLER, M.-O.   Networks of Mixed Canonic-Dissipative Systems and Dynamic Hebbian Learning. In Proceedings of INDS'08 - First International Workshop on Nonlinear Dynamics and Synchronization, 2008.

Theses

RODRIGUEZ, J.   Noise and Delays in Adaptive Interacting Oscillatory Systems. PhD thesis presented at the Universität Bielefeld, supervised by Professor Ph. BLANCHARD (Fakultät für Physik, Uni. Bielefeld), 2013. [link to .pdf file]

RODRIGUEZ, J.   Networks of Self-Adaptive Dynamical Systems. PhD thesis presented at the Ecole Polytechnique Fédérale de Lausanne, supervised by Professor M.-O. HONGLER (Faculté des Sciences et Techniques de l'Ingénieur, EPFL), 2011. [link to .pdf file]

RODRIGUEZ, J.   A New Portfolio Optimization Based on Entropy. Master thesis in Mathematics presented at the Université de Genève, supervised by Professor M. GANDER (Section de mathématiques) and Professor M. GILLI (Département d'économétrie), 2007. [link to .pdf file]





Talks

06-09.06.2023   Network of Adaptive Frequency Oscillators in a Ballistic (i.e., non- Gaussian) Noisy Environment. ASMDA 2023, 20th Applied Stochastic Models and Data Analysis International Conference, Hellenic Mediterranean University, Heraklion, Crete, Greece.

07.10.2022   Tilted washboards and Chaotic Dynamics in a Vintage Rotating Roasting Spit. researchXchange, Berner Fachhochschule, Departement Technik und Informatik, Burgdorf, Schweiz.

26.04.2022   Yves Rocard et le tournebroche chaotique: Comment Yves Rocard doctement régulait un tournebroche potentiellement chaotique. Colloque inaugural de l'Institut Jules Verne, Hommage à Yves Rocard, Université de Toulon, Palais Neptune de Toulon, Toulon, France.

09-12.06.2020   How chaotic dynamics drive a vintage grill-room spit. CHAOS 2020, 13th Chaotic Modeling and Simulation International Conference, Grand Hotel Adriatico, Florence, Italy (Virtual Conference due to Coronavirus).

11-12.10.2018   How chaotic dynamics drives a vintage grill-room spit. EPFL and FEMTO-ST's SMYLE workshop on "Oscillators", EPFL Microcity, Neuchâtel, Switzerland.

25.11.2016   Noisy AFOs and Directed Networks. Workshop on Adaptive Frequency Oscillators, Biorobotics Laboratory, EPFL, Lausanne, Switzerland.

22-26.09.2014   Adaptive Frequency KURAMOTO Dynamics in Directed Commuting Networks. ECCS'14 - European Conference on Complex Systems, IMT Institute for Advanced Studies Lucca, Lucca, Italy.

10.07.2013   Frequency Adaptation in Directed Networks of Phase Oscillators, Department of Information Sciences, Ochanomizu University, Tokyo, Japan.

05.07.2013   Brief Overview on Synchronization and Adaptation in Oscillatory Networks, SMART Seminar, Tohoku University, Sendai, Japan.

27-29.06.2013   Adaptation in Networks of Periodic Dynamical Systems, Workshop on nonlinear PDEs - PDE approach to network and related topics, Tohoku University, Sendai, Japan.

17.06.2013   Adapting Coupled Periodic Stable Signals, Enreiso Seminar, Hokkaido University, Sapporo, Japan.

04.03.2013   Noise and Delays in Adaptive Interacting Oscillatory Systems. IGK Seminar, Universität Bielefeld, Bielefeld, Deutschland.

15-18.10.2012   Networks of Adaptive Frequency Oscillators and Stochastic Parametric Resonance. Stochastics and Real World Models: Recent Progress and New Frontier, School of Mathematical Science, Jiangsu Normal University, Xuzhou, People's Republic of China.

02.10.2012   Stochastic Switching Networks of Adaptive Frequency Oscillators. Departamento de Ciencias Matemátics, Universidad de Puerto Rico - Recinto de Mayagüez, Mayagüez, Puerto Rico.

26.09.2012   Networks of Adaptive Frequency Oscillators with Time-Dependent and Delayed Interactions. Sonderforschungsbereich 910 - Control of self-organizing nonlinear systems: Theoretical methods and concepts of application, Institut für Theoretische Physik, Technische Universität, Berlin, Deutschland.

25.09.2012   Time Delayed Interactions in Networks of Self-Adapting Hopf Oscillators. Seminar Netzwerke und Komplexe Systeme, Max-Planck-Institut für Mathematik in den Naturwissenschaften, Leipzig, Deutschland.

02-06.07.2012   Stochastic Parametric Resonance in Networks of Adaptive Frequency Oscillators. Random Models in Neuroscience, Université Pierre et Marie Curie, Paris, France.

08.06.2012   Networks of Vibrating-Oscillatory Systems with Parametric Resonance Type Perturbation. INRIA - NeuroMathComp, Sophia Antipolis, France.

20-27.05.2012   Noise Induced Dynamical Patterns for a Swarm's Barycenter. Emergent Dynamics of Oscillatory Networks, Санаторий "Меллас", поселок Санаторый, Ялта, Крым, Україниа.

04-06.04.2012   Frequency Adaptation and Attractor Shaping in Oscillatory Networks. Nonlinear Analysis and Applications, Національний технічний університет України "Київський полі технічний інститут", Київ, Україниа.

25-27.07.2011   Self-Adaptive Attractor-Shaping for Oscillators Networks. INDS'11 & ISTET'11 - Third International Workshop on nonlinear Dynamics and Synchronization and Sixteenth International Symposium on Theoretical Electrical Engineering, Alpen-Adria-Universität Klagenfurt, Klagenfurt, Österreich.

18-22.07.2011   Globally Coupled Phase Oscillators driven by Ballistic Noise Source. Stochastics and Real World Models 2011, Universität Bielefeld, Bielefeld, Deutschland.

13-17.09.2010   Parametric Resonance in Time-Dependent Networks of Phase Oscillators. ECCS'10 - European Conference on Complex Systems, ISCTE - Instituto Universitário de Lisboa (Instituto Superior de Ciências do Trabalho e da Empresa), Lisboa, Portugal.

05-09.07.2010   Networks of Adaptive Frequency Oscillators and Parametric Resonance. Nonlinear Dynamics on Networks, Національна академія наук України, Київ, Україниа.

12.05.2010   Parametric Resonance in Networks of Adaptive Frequency Oscillators. Sfb 555 - Complex Nonlinear Processes, Institut für Physik, Humboldt-Universität, Berlin, Deutschland.

03-07.05.2010   Networks of Limit Cycle Oscillators with Parametric Dynamics. Chinese-German Meeting on Stochastic Analysis and Related Fields, Academy of Mathematics and Systems Science, Chinese Academy of Science, Beijing, People's Republic of China.

14-18.02.2010   Frequency Adaptation in Networks of Coupled Limit Cycle Oscillators. SOCONT - Stochastic Optimal Control, Quinta Bela São Tiago Hotel, Funchal, Madeira, Portugal.

26-31.07.2009   Globally Coupled Phase Oscillators with Super-diffusive Noise. Madeira Math Encounters XXXVII, Centro de Ciências Matemáticas, Universidad da Madeira, Funchal, Madeira, Portugal.

20-21.07.2009   Noise Induced Temporal Patterns in Populations of Globally Coupled Oscillators. INDS'09 - Second International Workshop on Nonlinear Dynamics and Synchronization, Alpen-Adria-Universität Klagenfurt, Klagenfurt, Österreich.

10.06.2009   Networks of Limit Cycle Oscillators with Plastic Dynamics. Rencontre franco-suisse sur le bruit et les non linéarités, Laboratoire de Psychologie et NeuroCognition, Université Pierre-Mendès France, Grenoble, France.

25-29.05.2009   Networks of Mixed Canonical-Dissipative Systems with Plastic Dynamics. Stochastics and Real World Models 2009, Universität Bielefeld, Bielefeld, Deutschland.

24.10.2008   Network of Limit Cycle Oscillators with Parametric Learning Capability. Seminar Analysis und Numerik, Mathematisches Institut, Universität Basel, Basel, Schweiz.

18-19.07.2008   Networks of Mixed Canonic-Dissipative Systems and Dynamic Hebbian Learning. INDS'08 - First International Workshop on Nonlinear Dynamics and Synchronization, Alpen-Adria-Universität Klagenfurt, Klagenfurt, Österreich.

14.05.2008   Networks of Mixed Canonic-Dissipative Systems and Dynamic Hebbian Learning. Séminaire d'analyse numérique, Section de mathématiques, Université de Genève, Genève, Suisse.

07.03.2007   A portfolio optimization based on entropy. Swissquote Bank SA, Gland, Suisse.





Research Visits and Exchange Stays

24.05-06.08.2013   Invited by Professor OBATA to participate in the Tohoku University's Focused Research Project "Interdisciplinary Mathematics Toward Smart Innovations", Graduate School of Information Sciences, Tohoku University, Sendai, Japan.

20.07-20.08.2012   Collaboration with the Beijing-Bielefeld Internationales Graduiertenkolleg (IGK) - Stochastics and Real World - team at the Academy of Mathematics and Systems Science, Chinese Academy of Science, Beijing, People's Republic of China.

16.07-15.08.2010   Collaboration with the Beijing-Bielefeld Internationales Graduiertenkolleg (IGK) - Stochastics and Real World - team at the Academy of Mathematics and Systems Science, Chinese Academy of Science, Beijing, People's Republic of China.