Thesis (M.S.)--University of Michigan, 1988.

Thesis (M.S.)--University of Michigan, 1981. / "A thesis submitted in partial fulfillment ... in pedodontics ..."

Thesis (M.S.)--University of Michigan, 1974.

Thesis (M.S.)--University of Michigan, 1986.

Thesis (M.S.)--University of Michigan, 1974.

Non-contact life detection is a significant component of both civilian and military rescue applications. As a consequence, this interest has resulted in a very active area of research. The primary goal of this research is reliable detection of a human breathing signal. Additional goals of this research are to carry out detection under realistic conditions, to distinguish between two targets, to determine human breathing rate and estimate the posture. Range gating and Singular Value Decomposition (SVD) have been used to remove clutter in order to detect human breathing under realistic conditions. However, the information of the target range or what principal component contains target information may be unknown. DFT and Short Time Fourier Transform (STFT) algorithms have been used to detect the human breathing and discriminate between two targets. However, the algorithms result in many false alarms because they detect breathing when no target exists. The unsatisfactory performance of the DFT-based estimators in human breathing rate estimation is due to the fact that the second harmonic of the breathing signal has higher magnitude than the first harmonic. Human posture estimation has been performed by measuring the distance of the chest displacements from the ground. This requires multiple UWB receivers and a more complex system. In this thesis, monostatic UWB radar is used. Initially, the SVD method was combined with the skewness test to detect targets, discriminate between two targets, and reduce false alarms. Then, a novel human breathing rate estimation algorithm was proposed using zero-crossing method. Subsequently, a novel method was proposed to distinguish between human postures based on the ratios between different human breathing frequency harmonics magnitudes. It was noted that the ratios depend on the abdomen displacements and higher harmonic ratios were observed when the human target was sitting or standing. The theoretical analysis shows that the distribution of the skewness values of the correlator output of the target and the clutter signals in a single range-bin do not overlap. The experimental results on human breathing detection, breathing rate, and human posture estimation show that the proposed methods improve performance in human breathing detection and rate estimation.

No description available.

Ability to duplicate an inspired volume level was studied in five healthy males using the psychophysical method of reproduction. Three conditions were evaluated in order to investigate the perceptual cues used for obtaining a specific inspired volume. Conditions were designed to progressively remove cues that might affect the subject's ability to duplicate an inspired lung volume. In each, the subject performed a standard inspiration, spanning from end expiratory position to 35% of inspiratory capacity. Conditions were varied as follows: (1) subjects were instructed to perform both the standard and test (reproduction) inspirations at the same flow rate and beginning at the same lung volume, (2) subjects were instructed to make the flow rate of the test inspiration faster or slower from standard inspiration, and (3) subjects were instructed to begin the test inspiration at a different lung volume than the standard inspirations. The group mean error for all conditions combined for the first day on which each condition was performed was 173 ml, compared to a mean error of 133 ml. Reduction in errors for all conditions from the first to the second day of performance indicates a practice effect. There was no significant difference in errors between conditions. These results indicate the final lung volume, which remained constant for all three conditions, is important for accurate duplication of inspired volume. This finding for learned respiratory movements is comparable to that found by other researchers for skilled limb movements.

A negative pressure quantitative fit testing device was used to test the effect exercise protocol has on leakage rates into a negative pressure respirator. Modified exercise protocols were developed for use with the negative pressure system. Aerosol data was analyzed to determine the effect exercises have had on leakage rates using other QNFT systems. Results show that the position of the head affects the amount of leakage into the facepiece. Mean leakage into the respirator mask increased for all positions tested in one phase of the study. However, statistical analysis of the data showed that the increase was not statistically significant. Aerosol data analysis also showed that increases in leakage into the mask were not statistically significant. Conclusions drawn from this study are that although movement of the head may affect the leakage into a respirator it is not significant enough to alter the protection afforded the worker.

This study determined the parameters which affect the internal mask inspiratory pressure and flow rate during respirator wear. The average inspiratory pressure and inspiratory flow rate were measured on 30 subjects who performed various submaximal work rates on a cycle ergometer while wearing air purifying respirators. The half-mask and full-face respirators were equipped with three levels of cartridge resistance. The results indicated that work rate, cartridge resistance, and mask type affected the inspiratory pressure and flow rate significantly. The findings of this study would allow the quantitative negative pressure respirator fit test to evaluate respirator fit over a wide range and representative of actual work condition.