Dr. Jiann-Shiun Lew

• EDUCATION
  
  Ph.D., Aerospace and Mechanical Engineering, State University of New York at Buffalo, 1988.
  M.S., Aerospace and Mechanical Engineering, State University of New York at Buffalo, 1986.
  B.S., Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan, 1982.
  
  
• AREAS OF RESEARCH
  
  Structural Damage Detection, Integration of System Identification and Robust Controller Designs, Machinery Monitoring and Diagnosis, System Identification for Large Flexible Structures.
  
  
• CURRENT RESEARCH PROJECTS
  
  Structural Damage Detection
  The operation of structures such as spacecraft, aircraft, ground vehicles, and weapons systems is sensitive to the damage of the structural components. To maintain the performance and safe operation of the systems, one must monitor the mechanical health of the structures. Recently we have developed an approach for damage detection of structures by using only a few sensors. The research is to develop an effective and inexpensive technology to detect structural damage.
  This research is funded by NASA Headquarters.
  
  System Identification for Robust Control Design
  Modeling a dynamic system with uncertainties and parametric changes is an important and challenging task for researchers in system identification and robust control communities. Recently we have developed an approach that can precisely quantify model uncertainty via the intervals of transfer function coefficients. The research is to develop an effective tool to model a dynamic system with uncertainty directly from experimental data for robust control design.
  This research is funded by NASA Headquarters.
  
  Machinery Monitoring and Diagnostics
  Machinery condition monitoring and fault diagnosis are crucial for effective maintenance in industry.
  
  
• REFEREED PUBLICATIONS
  
  Lew, J.-S., and Lim, K. B., ``Model Reduction of Interval System for Robust Control,'' 16th ASME Biennial Conference, September 14-17,1997.
  
  Lew, J.-S., ``Transfer Function Parameter Changes Due to Structural Damage,'' 1997 AIAA/ASME/AHS Adaptive Structures Forum, Kissimmee, Florida, April 7-10, 1997.
  
  Lew, J.-S., Sathananthan, S., and Gu, Y., ``Comparison of Damage Detection Algorithms Using Time Domain Data,'' 15 International Modal Analysis Conference, Orlando, Florida, February 3-6, 1997.
  
  Link, T., Lew, J.-S., Garcia, E., and Keel L. H., ``Interval Model Identification and Robustness Analysis for Uncertain Flexible Structures,'' IEEE Transactions on Control Systems Technology}, Vol. 4, No. 3, 1996, pp. 411-418.
  
  Lew, J.-S., ``Torque Converter Clutch Slip Control with Friction Uncertainty,'' SAE paper 960432, 1996.
  
  Lew, J.-S., ``Using Transfer Function Parameter Changes for Damage Detection of Structures,'' AIAA Journal, Vol. 33, No. 11, 1995, pp. 2189-2193.
  
  Lew, J.-S., ``Comparison of Interval Modeling Techniques for Structures with Uncertain Parameters,'' 5th International Conference on Adaptive Structures, Technomic Publishing Co., Inc., 1995, pp. 194-205.
  
  Lew, J.-S., Keel L. H., and Juang J.-N., ``Quantification of Parametric Uncertainty via an Interval Model,'' Journal of Guidance, Control, and Dynamics, Vol. 17, No. 6, 1994, pp. 1212-1218.
  
  Lew, J.-S., Link, T., Garcia, E., and Keel L. H., ``Interval Model identification for Flexible Structures with Uncertain Parameters,'' Proceedings of Adaptive Structures Forum, Hilton Head, SC, April 21-22, 1994.
  
  Link, T., Lew, J.-S., Garcia, E., and Keel L. H., ``Robustness Verification for Flexible Structures via Interval Control Systems,'' Proceedings~ of ~AIAA~ Guidance,~ Navigation,~ and~ Control~ Conference, Scottsdale, August 1-3, 1994.
  
  Keel, L. H., Lew, J.-S., and Bhattacharyya, S. P., ``System Identification Using Interval Dynamic Models,'' Proceedings of the American Control Conference, Baltimore, MD, June 29-July 1, 1994.
  
  Lew, J.-S., Juang J.-N., and Longman R. W., ``Comparison of Several System Identification Methods for Flexible Structures,'' Journal of Sound and Vibration, Vol. 167, No. 3, 1993, pp. 461-480.
  
  Lew, J.-S., Keel L. H. and Juang J.-N., ``Quantification of Model Error via an Interval Model with Nonparametric Error Bound,'' Proceedings of 1993 AIAA Guidance, Navigation, and Control Conference, Monterey, CA, August 9-11, 1993.
  
  Lew, J.-S.,``Application of Singular Value Decomposition for Static Equilibrium Analysis of Mechanical Systems'', 1993 ASME Design Automation Conference, DE-Vol. 65-2, Albuquerque, NM, Sep. 19-22, 1993.
  
  Longman, R., Lew, J.-S., and Juang, J.-N., ``Comparison of Candidate Methods to Distinguish Noise Modes from System Modes in Structural Identification,'' Proceeding of the 1992 AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, April 13-15, 1992.
  
  Lew, J.-S., and Mook, D. J., ``Jump Discontinuous Two Point Boundary Value Problems in Optimal Control,'' Proceedings of the 1992 American Control Conference.
  
  Lew, J.-S., Juang J.-N., and Longman R. W., ``Comparison of Several System Identification Methods for Flexible Structures,'' , Proceedings of the 32nd AIAA Structures, Structural Dynamics, and Materials Conference, 1991.
  
  Longman R. W., Lew, J.-S., Tseng, D.-H., and Juang J.-N., ``Variance and Bias Computation for Improved Modal Identification Using ERA/DC,'' Proceedings of American Control Conference, 1991.
  
  Mook, D.-J., and Lew, J.-S., ``Multiple Shooting Algorithms for Jump-Discontinuous Problems in Optimal Control and Estimation,'' IEEE Transactions on Automatic Control, 1991.
  Mook, D.-J., and Lew, J.-S., ``An Existence and Uniqueness Proof for the Minimum Model Error Optimal Estimation Algorithm,'' Journal of Guidance, Control, and Dynamics, 1991.
  
  
• CONTACT
  
  lew@coe.tnstate.edu
  
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