||Hun H. Sun, Ph.D.
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Professor Emeritus, School of Biomedical Engineering, Science & Health Systems
Professor Emeritus, Electrical & Computer Engineering
Biological control systems,physiological modeling, systems analysis.
Ph.D., Cornell University, Electrical Engineering, 1955
Active Research Projects:
Noninvasive Cardiac Impedance Monitoring device to detect various cardiac functions (e.g. cardiac output, ejection fraction) and other critical circulatory parameters in place of the present use of invasive methods using pulmonary artery catheterization in the hospital's Intensive Care Unit (ICU).
"Identification of Nonlinear System with Feedback Structure," with Shi. Chapter in Advanced Method in Physiological System Identification, vol. 3, V. Z. Marmarelis, ed., Plenum Publishing, Co., 1994.
"Fractal System as Represented by Singularity Function," with Charef, Tsao, and Onaral. IEEE-Trans Automatic Control, pp. 1465-1470, June 1992.
"Fractal System-A Time Domain Approach," with Charef. Annals of Biomedical Eng., vol. 18, pp. 597-631, 1990.
"Nonlinear System Identification for Cascaded Block Model: An Application to Electrode Polarization Impedance," with Shi. IEEE Trans. B. E., vol. 37, pp. 574-587, June 1990.
"Impedance Cardiography and Heart Monitoring Device (IQ System)" Dr. Xiang Wang and Dr. Hun H. Sun. US Patent #5,309,917, #5,423,326 and #5,443,073 1995.
NOTE: On February 9, 2001, the intellectual property for this device was assigned by Drexel University to Wantagh Inc with the exclusive rights for the manufacturing and marketing of the IQ System.
A method to identify a general class of nonlinear systems that satisfy the Volterra-Wiener conditions has been developed by using the parallel cascade model. A systematic procedure has been developed to construct a model from input-output data and each of the cascaded branch consists of only one nonlinear element. The model is built up iteratively so that the number of parallel branches is limited by a prescribed error.
A method to represent fractal system by using time domain method has been developed. The fractal system is represented by a set of time-variant differential equations. Asymptotic solutions are obtained and the time behaviors of the fractal system are therefore analyzed.
A new impedance cardiography system has been developed to measure cardiac function non-invasively. It is based on the time-frequency distribution method and enables us to obtain well-defined indications of the various points on the time derivations of the impedance signal. Clinical testing were made on this non-invasive method against the gold-standard invasive thermodilution method and all results show much better correlation than any other IC systems available.