Dr. Hemdal is currently serving as Project Manager for electrical and controls engineering and acoustic/vibration projects.

Dr. Hemdal has over twenty years of experience in the field of electronics, acoustics, energy, computers, digital communications and signal processing.

Prior to joining ZEI, Dr. Hemdal served as Associate Professor and later as Assistant Chairman and Professor Emeritus in the Department of Electrical Engineering at the University of Toledo. Dr. Hemdal also served on the Academic Advisory Board at the Cleveland Institute of Technology.

Past projects have included image processing, pattern recognition, speech input to computers, the application of parallel processors to machine vision, inspection and quality control, and acoustics and noise control.

In 1964, Dr. Hemdal was a member of the Acoustics and Seismics Laboratory at the University of Michigan's Institute of Science and Technology, where he performed research in the field of signal detection and recognition of seismic records. He also assisted in other digital problems in signal processing, phase equalizing, correlation techniques, wave propagation and seismic arrays.

Dr. Hemdal has served as a Research Acoustician and head of the Geophysics Section of the Environmental Research Institute of Michigan. In this capacity, he has worked in a variety of areas including remote sensing, acoustic pattern recognition, speech recognition, acoustic propagation, noise pollution, vehicle signature studies, psycho-acoustics and acoustic annoyance. While at the ERI, Dr. Hemdal led a technical team to investigate the feasibility of centralized site electric power generation utilizing waste heat for the Federal Energy Administration. This work led to his authoring a book entitled "Energy Centers: New Alternatives for Effective Energy Use," which was published by Ann Arbor Science Publishers.

Dr. Hemdal was Principal Investigator of several studies related to the automatic identification of acoustic and seismic sources using pattern recognition techniques.

Dr. Hemdal was Principal Investigator of a number of research projects including a study of the effect of turbulence on acoustic arrival times, errors in the measurement of the sound emission from motor vehicles, OSHA-type measurements in the workplace, energy conservation and others.

Dr. Hemdal has contributed to studies in acoustics, including architectural and atmospheric acoustics, the effect of turbulence on sound emission, detection and recognition of seismic signals, digital signal processing, correlation techniques, wave propagation and many others.

Dr. Hemdal also has conducted experiments in psycho-acoustics designed to test distinctive feature descriptions of acoustic phonetics. He also developed an analog simulation of the basilar membrane of the human ear which resulted in contributions to the theory of the residue in hearing.

BS, Electrical Engineering, Purdue University
MS, Electrical Engineering, Purdue University
Ph.D., Electrical Engineering, Purdue University

Registered Professional Engineer in Michigan

Institute of Electrical and Electronic Engineers
Association of Energy Engineers
Institute of Noise Control Engineering
Acoustic Society of America
National Society of Professional Engineers
Michigan Society of Professional Engineers

Dr. Hemdal has published over 50 technical articles, papers and reports, some of which are listed below:

"A Preliminary Survey of Some Major Factors Bearing on the Feasibility of Energy Centers in Michigan," co-author and editor, prepared for the Federal Energy Administration, 1976.

Energy Centers; A New Alternative for Effective Energy Use, Ann Arbor Science Publishers, Ann Arbor, Michigan, 1979, 277 pp.

"Analog Computer Simulation of the Basilar Membrane," unpublished paper presented at the 63rd meeting of the Acoustical Society of America. Abstract JASA, May 1962.

"The Applications of Distinctive Features to the Primary Recognition of Speech," Doctoral Dissertation, University Microfilms, Ann Arbor, Michigan, 1964.

"Speech Analysis," co-author, Final Report, School of Electrical Engineering, TR-EE65-9, July 1965, AFCRL 65-681, Purdue University.

"An Application of Digital Inverse Filtering to the Systematic Variation of Vowel Parameters," in Studies in Language and Language Behavior, II (H.L. Lane, ed.), Ann Arbor; CRLLB, The University of Michigan, 1966.

"A Feature Based Computer Recognition Program for the Modeling of Vowel Perception," The Proceedings of the Symposium on Models for the Perception of Speech and Visual Form, Data Sciences Laboratory, AFCRL, November 1964, MIT Press, 1967 (W. Wathen-Dunn, ed.).

"An Error Analysis of Digital Equalizing Filters," Earthquake Notes, Vol. 37, Nos. 3-4, September, December 1967, pp. 11-33.

"An Investigation of Factors Affecting Sound Ranging: Literature Search and Analysis," Final Report 6400-209-T, The University of Michigan, Geophysics Lab., Willow Run Labs., June 1970.

"Seismic and Meteorological Research Program (U)," co-author, Final Report 1111-11-F, The University of Michigan, Geophysics Lab., for Stanford Research Institute, Vol. 1 (SECRET), Vol. II (UNCLASSIFIED), October 1968.

"Some Simple Rules for Self-Adaptive Mechanical Recognition of Vowels," The Proceedings of the Conference on Language and Language Behavior, University of Michigan, Ann Arbor, Appleton-Century-Crofts, 1968 (Eric M. Zale, ed.).

"An Investigation of Automatic Identification of Acoustic and Seismic Sources," Final Report 36990-3-F, The University of Michigan, Geophysics Lab., Willow Run Labs., July 1971.

"An Investigation of Automatic Identification of Acoustic and Seismic Sources, Final Report 10201-4-F, The University of Michigan, Geophysics Lab., Willow Run Labs., September 1972.

"A Study of Repeatability at Motor Vehicle Noise Measurement Test Sites," ERIM, Geophysics Laboratory for Ford Motor Company, Report 301300-1-F, August 1973. Also Paper No. 740968, The Journal of the Society of Automotive Engineers, 1975.

"Estimation of Error in Motor Vehicle Noise-Level Measurements," Journal of the Acoustical Society of America, Vol. 56, No. 6, December 1974, pp. 1801-1804.

"The Effect of Environmental Variables on Truck Noise Emission," co-author, to be published Noise-Con Proceedings, 1980.

"Effects of Environmental Variables on Truck Noise Emission and Noise Propagation to Test Microphones," co-author, Journal of Air Acoustical Society of America, Vol. 76, No. 4, October 1984, pp. 1150-1160.