Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 13 of 13 for “"periodic signal"”.
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Frequency Estimation Using Time-Frequency Based Methods
Any periodic signal can be decomposed into a sum of oscillating functions. Traditionally, cosine and sine segments have been used to represent a single period of the periodic signal (Fourier Series). In more general cases, each of these functions can be represented by a set of spectral parameters …
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Enhanced Energy Harvesting for Rotating Systems using Stochastic Resonance
… in nonlinear bistable systems whereby a weak periodic signal can be significantly amplified with the aid of inherent noise or vice versa. Stochastic resonance can thus be used to amplify the noisy and weak vibration motion. Through mathematical modeling, this dissertation shows that stochastic …
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A global and tropical quasi-decadal oscillation of the atmosphere and Ocean
An oscillatory, quasi-periodic signal with a period of around 10 years was found in radiosonde- and satellite-measured datasets of lower stratospheric temperature. Power spectrum analysis and Fourier decomposition were used to characterize the temporal and vertical manifestations of the signal, …
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The oscillogenic control algorithm
… controller) and a sensor component to produces a periodic signal yielding information about the instrument's sensor component. A control program that utilized the oscillogenic control algorithm was written in the Turbo Pascal programming language. An IBM PC with 640 kilobytes of read/write memory …
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The Determination of the Half-Life of Si-32 and Time Varying Nuclear Decay
… a 4 yr period and reported unexplained annual periodicities. Utilizing the very same sources and shuffling apparatus, we have observed the decay of $^{32}$Si and $^{36}$Cl for more than 6,000 hours each, over the last $\sim 2$ yr, while recording $\sim 5\times 10^6$ individual environmental …
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The Removal Of Motion Artifacts From Non-invasive Blood Pressure Measurements
… the blood pressure waveform and use Digital Signal Processing Techniques to process the corrupted waveform. We use the differences in frequency spectra of the Blood Pressure signal and motion artifact noise to remove the motion artifact noise. The motion artifact noise spectrum is not very …
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Inverter design and analysis using multiple reference frame theory
"Multiple reference frame theory allows for periodically time varying signals to be represented as a set of dc signals. In other words, every periodic signal can be expanded into a Fourier series representation. By modeling an inverter connected to a boost maximum power point tracker (MPPT) in this …
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Control of Multiple Degree of Freedom Fast Tool Stages for Noncircular Turning Process
… for small variations in the period of the periodic signal. A systematic controller design methodology is presented to guarantee the robust stability. Experimental and simulation results from an electrohydraulic actuator system validate this approach.
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Characterization of fluvial facies distributions and cyclicity using terrestrial lidar: Paleocene Nacimiento Formation, Kutz Canyon, New Mexico
… conducted on the lidar intensity data yielded a periodic signal at 6.5 m over a vertical thickness of 25 m. The recurrence interval of this signal is estimated to be approximately 34 kya and is interpreted as depositional products of successive avulsion episodes, or depositional lobe switching on …
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Formal verification of analog and mixed signal circuits using deductive and bounded approaches
… of inevitability of states in analog and mixed signal (AMS) circuits. Two techniques to verify the inevitability of phase locking in a Charge Pump Phase Lock Loop (PLL) circuit are presented: mixed deductivebounded and deductive-only verification approaches. The deductive-bounded approach uses …
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Noncontact heart rate measurement via period detection methods of periodic signals
… The aim of this work is to apply different signal processing methods utilized in pitch detection problems of periodic signals, namely zero-crossings, autocorrelation, maximum likelihood and Fourier-based methods, to the signal obtained from the average pixel values of the frames of a video …
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Prediction of Inlet Distortion Transfer Through the Blade Rows in a Transonic Axial Compressor
… Volterra theory can be used to model any periodic nonlinear system as an infinite sum of multidimensional convolution integrals. A semi-empirical model has been developed using this theory by assuming that a distortion waveform is a periodic signal that is being presented to a nonlinear …
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A Versatile and Computationally Efficient Condition Indicator for AH-64 Rotorcraft Gearboxes
… dividing the total energy in the raw time domain signal with the energy in the time synchronous averaged signal of the component with synchronous frequency equal to the component's frequency. The ASET CI has ability to identify modulation of synchronous frequencies, and change in gear mesh …