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This study uses flow rate and blood oxygen saturation signals to detect apnea and hypopnea events. The detection process consist two phases, by using the peaks of flow rate signals to determine respiratory cycles, the first phase uses seven flow rate feature to distinguish normal and abnormal respiratory events. To reduce the false detection rate, by appending two additional blood oxygen saturation variables into the feature set, the second phase tries to filter out some falsely detected events made in the first phase. Experimental results show that the proposed approach achieves detection accuracy is 81%. The corresponding false detection rate is 67%. One reason for the high false detection rate is that many normal respiratory events has lower amplitude airflow pattern. To resolve such a difficulty, additional physiological signals may be required.

This thesis describes an investigation into the use of dual modality tomography to measure component concentrations within a cross-section. The benefits and limitations of using dual modality compared with single modality are investigated and discussed. A number of methods are available to provide imaging systems for process tomography applications and seven imaging techniques are reviewed. Two modalities of tomography were chosen for investigation (i.e. Electrical Impedance Tomography (EIT) and optical tomography) and the proposed dual modality system is presented. Image reconstruction algorithms for EIT (based on modified Newton-Raphson method), optical tomography (based on back-projection method) and with both modalities combined together to produce a single tomographic imaging system are described, enabling comparisons to be made between the individual and combined modalities. To analyse the performance of the image reconstruction algorithms used in the EIT, optical tomography and dual modality investigations, a sequence of reconstructions using a series of phantoms is performed on a simulated vessel. Results from two distinct cases are presented, a) simulation of a vertical pipe in which the cross-section is filled with liquid or liquid and objects being imaged and b) simulation of a horizontal pipe where the conveying liquid level may vary from pipe full down to 14% of liquid. A computer simulation of an EIT imaging system based on a 16 electrode sensor array is used. The quantitative images obtained from simulated reconstruction are compared in term of percentage area with the actual cross-section of the model. It is shown from the results that useful reconstructions may be obtained with widely differing levels of liquid, despite the limitations in accuracy of the reconstructions. The test results obtained using the phantoms with optical tomography, based on two projections each of sixteen views, show that the images produced agree closely on a quantitative basis with the physical models. The accuracy of the optical reconstructions, neglecting the effects of aliasing due to only two projections, is much higher than for the EIT reconstructions. Neglecting aliasing, the measured accuracies range from 0.1% to 0.8% for the pipe filled with water. For the sewer condition, i.e. the pipe not filled with water, the major phase is measured with an accuracy of 1% to 3.4%. For the single optical modality the minor components are measured with accuracies 6.6% to 19%. The test results obtained using the phantoms show that the images produced by combining both EIT and optical tomography method agree quantitatively with the physical models. The EIT eliminates most of the aliasing and the results now show that the optical part of the system provides accuracies for the minor components in the range 1% to 5%. It is concluded that the dual modality system shows a measurable increase in accuracy compared with the single modality systems. The dual modality system should be investigated further using laboratory flow rigs in order to check accuracies and determine practical limitations. Finally, suggestions for future work on improving the accuracy, speed and resolution of the dual modality imaging system is presented.

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SAS has become an increasingly important public-health problem in recent years. It can adversely affect neurocognitive, cardiovascular, respiratory diseases and can also cause behavior disorder. Since up to 90% of these cases are obstructive sleep apnea (OSA), therefore, the study of how to diagnose, detect and treat OSA is becoming a significant issue, academically and medically. Polysomnography (PSG) can monitor the OSA with relatively fewer invasive techniques. However, PSG-based sleep studies are expansive and time-consuming because they require overnight evaluation in sleep laboratories with dedicated systems and attending personnel. This work develops a flow rate based detection method for apneas. In particular, via signal processing, feature extraction and neural network, this thesis introduces a flow rate based detective system. The goal is to detect OSA with less time and reduced financial costs.

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<p> The pulse response of a full scale aeration tank is mathematically modelled with an arbitrary network of idealized perfectly mixed and plug flow component vessels. The model is fitted in the frequency domain, then inverse transformed to the time domain. The soluble carbon concentration curve of batch biokinetic run is modelled by a modified logistics equation and a piecewise linear expression. The mixing and kinetic models are combined to predict the degree of conversion assuming the degree of segregation, J, to be one. The pulse responses of a lab scale tank for varying water flow rates are also modelled by the same methods. An attempt is made to correlate the mathematical model parameters to the water flow rate. </p> / Thesis / Master of Engineering (MEngr)

A two-stage (carbon oxidation stage one, ammonia oxidation stage two) biological aerated filter was operated for 10 months on-site at a domestic wastewater treatment plant. Over the study, the system was operated at different hydraulic loading rates that resulted in a range of applied organic and ammonia mass loadings. Performance was monitored regularly for water quality parameters in the effluent and along the length of the reactors. It was found that nitrification performance was significantly influenced by organic loading rates greater than 1.2 kg cBOD5/m³-d. Additional experiments were conducted in which a constant mass of ammonia was applied (Phase 1: 1.40 ± 0.08 kg NH₃-N/m³-d; Phase 2: 1.31 ± 0.02 kg NH₃-N/m³-d) to the N column, the second stage of the system, over a range of hydraulic loading rates (5.1 -15.8 m/h). Phases of testing were defined by the background hydraulic loading rate applied to the system (Phase 1: 8.3 m/h; Phase 2: 7.1 m/h) at which the reactors were allowed to reach a steady effluent quality for at least one week prior to testing. Organic loading was minimized and kept relatively constant throughout the hydraulic loading rate experiments (0.65 ± 0.2 kg cBOD5/m³-d) in order to obtain an evaluation of nitrification capacity with minimal competition from heterotrophic bacteria. Results indicated that nitrification performance improved by 17% as the applied velocity increased over the indicated range. A steady-state biofilm model capable of predicting substrate flux was applied to the data in an attempt to explain the improvement in performance with hydraulic loading rate from a fundamental standpoint. Mass transfer coefficients, KL, were derived from the model for conditions in which the experimentally observed flux correlated with the model predictions. Derived KL values were lower than estimations offered by correlation equations but increased with velocity at a similar rate. The model failed to account for changes that may have occurred in biofilm kinetics and structure throughout the length of the reactor. / Master of Science

9 pp. / Martin, E.C. 2000. Determining the Amount of Water Applied to a Field. Cooperative Extension Pub. No. AZ1157, Arizona Water Series No. 29. University of Arizona, Tucson, AZ. Martin, E.C. 1999. Measuring Water Flow and Rate on the Farm. Cooperative Extension Pub. No. AZ1130, Arizona Water Series No. 24. University of Arizona, Tucson, AZ. / Measuring water is a critical part of any irrigation management system. This informational bulletin gives some simplistic methods of measuring flow rate in an open ditch and in gated pipe. Using the float method, dye tracers and velocity head meters, growers can get a quick estimate of the flow in their farm ditch. From this, an estimate of water applied or a set time can be determined. The bulletin also explains how a propeller meter works for gated pipe. Gated pipe is widely used through the state and in the West.