Dong Eui CHANG

Associate Professor

 

Department of Applied Mathematics

University of Waterloo

200 University Ave. W.

Waterloo, Ontario, N2L 3G1

Canada

 

Other affiliations

Computational Mathematics

Waterloo Institute for Complexity & Innovation

 

Office: MC6124

Phone: +1-519-888-4567, ext. 37213

Fax: +1-519-746-4319

Email: dechang \at\ uwaterloo \dot\ ca

 

Education

Ph.D. Control & Dynamical Systems, California Institute of Technology, 2002 (Advisor: Jerrold Marsden; photo)

M.S. Electrical Engineering, Seoul National University, 1997 (Advisor: In-Joong Ha)

B.S. Control Engineering, Seoul National University, 1994, summa cum laude


CV (including publications)

Publications (via Google Scholar)

 

Research Interests

Data Science (Machine Learning), Control, Mechanics, and Dynamical Systems.

 

Blurb on My Research Achievements

* Deep Learning: Setting a standard for Deep Learning

    - A Caterini and DE Chang, ``A Novel Representation of Neural Networks,'' arXiv:1610.01549.

    - A Caterini and DE Chang, ``A Geometric Framework for Convolutional Neural Networks,'' arXiv:1608.04374.

 

* Feedback Integrators: An excellent way to integrate the ODEs of dynamical systems

   - DE Chang, F Jimenez and M Perlmutter, ``Feedback Integrators,'' Journal of Nonlinear Science, 26 (6),1693 -- 1721, 2016. arXiv:1606.05005.

 

* Damping-induced self-recovery phenomenon in various physical systems: this fascinating phenomenon has been overlooked in the entire history of mechanics inclduing fluid mechanics.

      -    Our experiments: video 1, video 2, video 3(NEW), video 4(NEW)

      -    Video game (coded by P. Walekar at VJTI)

      -       D.E. Chang and S. Jeon, ``On the self-recovery phenomenon for a cylindrical rigid body rotating in an incompressible viscous fluid,'' ASME Journal of Dynamic Systems, Measurement, and Control,137(2), 021005, 2015.

-       D.E. Chang and S. Jeon, ``On the self-recovery phenomenon in the process of diffusion,'' Preprint at http://arxiv.org/abs/1305.6658.  

-       D.E. Chang and S. Jeon, ``On the damping-induced self-recovery phenomenon in mechanical systems with several unactuated cyclic variables,'' J. Nonlinear Science, 23 (6), 1023 -- 1038, 2013.

-       D.E. Chang and S. Jeon, ``Damping-induced self recovery phenomenon in mechanical systems with an unactuated cyclic variable,''  ASME Journal of Dynamic Systems, Measurement, and Control, 135(2), 021011, 2013.

 

* The energy shaping method for the stabilization of mechanical systems: the authoritative work in this area.

      -    D.E. Chang, ``On the method of interconnection and damping assignment and passivity-based control for the stabilization of mechanical systems,'' Regular and Chaotic Dynamics, 19 (5), 556 -- 575, 2014. arXiv

-   W. Ng, D.E. Chang and G. Labahn, ``Energy shaping for systems with two degrees of underactuation and more than three degrees of freedom,'' SIAM J. Control and Optimization, 51 (2), 881 -- 905, 2013    

-    D.E. Chang, ``Pseudo-energy shaping for the stabilization of a class of second-order  systems,'' International Journal of Robust and Nonlinear Control,  22(18), 1999--2013, 2012.

-       D.E. Chang, ``The method of controlled Lagrangians: Energy plus force shaping,'' SIAM J. Control and Optimization, 48 (8), 4821 -- 4845, 2010.

-   D.E. Chang, ``Stabilizability of controlled Lagrangian systems of two degrees of freedom and one degree of under-actuation,'' IEEE Trans. Automatic Control, 55 (8), 1888 -- 1893, 2010.

 

* Quasi-linearization of mechanical systems: we more or less closed a big chapter in this area of research in control and opened a new chapter.

-       D.E. Chang and R.G. McLenaghan, ``Geometric criteria for the quasi-linearization of the equations of motion of mechanical systems,'' IEEE Trans. Automatic Control, 58 (4), 1046 -- 1050, 2013.

 

* The shortest and simplest (one-page) proof of the Pontryagin Maximum Principle on manifolds.

-       D.E. Chang, ``A simple proof of the Pontryagin maximum principle on manifolds,'' Automatica,  47(3), 630 -- 633, 2011.

 

* The Lyapunov-based orbital transfer: all the people in aerospace engineering had been using orbital elements just as their ancestors  but I for the  first time broke out of the tradition and proposed the use of the angular momentum vector and the Laplace vector so that the controller law becomes simple and singularity-free.

-       D.E. Chang, D.F. Chichka, and J.E. Marsden, ``Lyapunov-based transfer between elliptic Keplerian orbits,''  Discrete and Continuous Dynamical Systems -- Series B, 2 (1), 57 -- 67, 2002.

 

* Engineering applications: quadcopters, quantum systems, flexible needle for surgery, dielectrophoretic systems; see relevant papers of mine.

 


 

Tutorials

Tutorial at 18th IFAC World Congress, Milan, Italy, 2011: Energy Shaping for the Stabilization of Mechanical Systems (Slides)

 

Paper related to the tutorial slides: D.E. Chang, ``On the method of interconnection and damping assignment and passivity-based control for the stabilization of mechanical systems,'' Regular and Chaotic Dynamics, 19 (5), 556 -- 575, 2014.: This paper has lots of  new results on IDA-PBC and puts IDA-PBC on serious but healthy diet, removing unnecessary redundancy. :  )


Book
* D.E. Chang, D.D. Holm, G. Patrick and T. Ratiu (Editors), Geometry, Mechanics, and Dynamics: The Legacy of Jerry Marsden, Springer, 2015.

 

 

 

Current Graduate Students

Anthony Caterini (Master)


Past Post-doc

Fernando Jimenez Alburquerque

 

Past Graduate Students

* Shaun Sawyer (Master 2015; thesis: Gain-scheduled control of a quadcopter UAV)

* Krishan Rajaratnam (Master, 2014; co-supservisioin with Ray McLenaghan; thesis: Orthogonal separation of variables of the Hamilton-Jacobi equation on spaces of constant curvature)

* Zhao Jin (Master, 2012; thesis: Application of repetitive control to the lateral motion in a roll-to-roll web system)

* Waiman Ng (Ph.D, 2011;co-supervision with George Labah; thesis: Energy shaping for systems with two degrees of underactuation)

* Joshua Fletcher (Master, 2010; thesis: Motion planning and observer synthesis for a two-span web roller machine)