Alfred Wilhelm Hubler

Associate Professor

Ph.D., Physics, Technical University of Munich, Germany, 1987

Alfred W. Hubler received his diplom in 1983 and Ph.D. in 1987, summa cum laude, from the Department of Physics, Technical University of Munich, Germany. After a postdoctoral fellowship at the University of Stuttgart, Germany, he came to the University of Illinois as a visiting assistant professor in 1989, and became assistant professor in 1990. Later that year, he also became the associate director of the Center for Complex Systems Research at Illinois, of which he is now the director. Professor Hubler served as a Toshiba Chair Professor at Keio University, Tokyo, in 1993-94.

Since beginning his thesis research, Professor Hubler has worked on nonlinear dynamics and has investigated a broad range of nonlinear phenomena. He is primarily a theorist, but he is also experienced in and capable of guiding both experimental and computational work. He has made solid contributions to the study of the chaotic dynamics in classical systems, both in idealized physical models and in engineering systems. He has been a pioneer in several important recent developments in nonlinear science research, including the control of chaos, the resonant coupling of nonlinear oscillators, and resonant stimulation and novel spectroscopies in nonlinear systems. Professor Hubler was among the very first to recognize that seemingly erratic, random motions associated with deterministic chaos could, in fact, be controlled, and that "chaotic" systems could be more "flexible" than systems undergoing more regular motion.

A skillful and committed teacher, Professor Hubler has also creatively applied the principles of nonlinear resonance to develop an intuitive, interactive web-based software package used to teach a variety of university science courses, at Illinois and around the world. Dubbed " CyberProf," the software analyzes student homework problems in real time and provides meaningful, intelligent, individualized feedback to each student.

Other Activities

System Identification with Nonlinear Resonances and Optimal Control of Adaptive and Non-adaptive Noisy Chaotic Systems Using the Chua Oscillator
All our research is centered around the idea of nonlinear resonances, their application for systems identification, optimal energy transfer and filters. We currently have five graduate students working on projects related to this. We use a specific system, the Chua oscillator, and study, experimentally and theoretically, system identification with nonlinear resonances and optimal control of adaptive and non-adaptive noisy, chaotic systems. We set up experimental chaotic Chua oscillators, both adaptive and non-adaptive, and compared the experimental results with numerical simulations and theoretical predictions. The dynamics Chua oscillator depends, very sensitively, on the control parameters in the chaotic regime. The Chua oscillator is like most other chaotic systems not structurally stable. Consequently even a minimal drift in the adjustment of any control parameters leads to qualitatively different dynamics. Experimentally a drift of the control parameters can be made small, but never completely suppressed, in contrast to computer simulations. Therefore experimental data sets appear to be non-stationary.

Center for Complex Systems Research
This is an interdisciplinary group of faculty and graduate students administered through the Department of Physics. This group investigates a variety of complex dynamic processes occurring in biology, physics, chemistry, astronomy, and engineering. It considers not only specific dynamic problems, but also the generic aspects of adaptive dynamic modeling and control that can be applied to any of the natural sciences or engineering.

For more information:

Blog

Honors and awards:

• Toshiba Chair Professor, Keio University, Japan, June 1993- Aug. 1994
• A. E. Nordsieck Award for Excellence in Graduate Teaching, 2006
• Center for Advanced Studies, UIUC, Fellowship Aug. 1991-May 1992
• Visiting Robert Maxwell Fellow, Santa Fe Institute, New Mexico, May 1991-July 1991
• Summer Fellowship, Institute for Scientific Interchange, Torino, Italy, Summer 1990
• Amoco Foundation Award for Innovation in Undergraduate Instruction, USA 1996

Selected Publications:

• T. Wotherspoon and A. Hubler, Adaptation to the edge of chaos with random-wavelet feedback. J. Phys. Chem. A 113 (1), 19–22 (2009).
• V. Gintautas and A. Hubler, Resonant forcing of nonlinear systems of differential equations. Chaos 18, 033118 (2008).
• J. Xu and A. W. Hubler, Detecting quasiperiodic structures with double diffraction. Europhysics Letters 81, 16002 (2008).
• V. Gintautas, G. Foster, and A. W. Hubler, Resonant forcing of select degrees of freedom of multidimensional chaotic map dynamics. J. Stat. Phys. 130 (3), 617-629 (2008).
• C. Strelioff, J. Crutchfield, A. Hübler, k-th Order markov chains: Bayesian inference, model comparison, entropy rate, and out-of-class modeling. Phys. Rev. E 76, 011106 (2007).
• A. Gerig and A. Hübler, Chaos in a one-dimensional compressible flow. Phys. Rev. E 75, 045202 (2007).
• V. Gintautas and A. Hübler. Experimental evidence for mixed reality states in an interreality system. Phys. Rev. E 75, 057201 (2007).
• M. S. Singleton and A. Hübler. Learning rate and attractor size of the single-layer perceptron. Phys. Rev. E 75, 026704 (2007).
• G. Foster, A. Hübler, and K. Dahmen. Resonant forcing of multidimensional chaotic map dynamics. Phys. Rev. E 75, 036212 (2007).
• C. Strelioff and A. Hübler. Medium term prediction of chaos. Phys. Rev. Lett. 96, 044101-1-4 (2006).