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 20 of 34 for “"Cyclostationary"”.
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Cyclostationary statistical optics
… treated theoretically within the framework of cyclostationary random processes. Propagation-induced effects for stochastic, pulsed fields that are either beam-like or plane waves are examined in the context of interferometric and spectroscopic measurements. Propagation of fields from more …
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Study of cyclostationary feature detectors for cognitive radio
… Commission (FCC) to be pioneered for CR usage. Cyclostationary feature of DVB signals is explored so that the robust single-cycle detector (SCD) can be employed to handle the problem of noise uncertainty, to which the widely used energy detector (ED) is susceptible. Due to complexity concerns …
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Random vibrations of bladed-disk assembly under cyclostationary excitation
… periodicity of the blade forces called cyclostationary. A random process is called wide sense eyeclostationary and its statistics are periodic in time. Factors like the turbulent nature of the flow around the blades, the variability in their geometry, and their nonuniform deterioration …
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Cyclostationary Methods for Communication and Signal Detection Under Interference
… (OFDM) signals and for exploiting the cyclostationary nature of signals to whiten the spectrum in blind signal detection. Data symbols are repeated in both time and frequency across orthogonal frequency division multiplexing (OFDM) symbols, creating a cyclostationary nature in the …
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Operational modal analysis and model updating with a cyclostationary input
… only that the system is excited by a so called cyclostationary input with a unique cyclic frequency, and that the log spectrum of the second order component of this input is frequentially smooth, as will be explained. Such systems include vehicles with internal combustion engines as the …
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FPGA IMPLEMENTATION OF A REALTIME CYCLOSTATIONARY FEATURE DETECTOR FOR OFDM SIGNALS
… operators in a given band. This thesis explores cyclostationary detection techniques for primary users. A method will be identified for the detection of the 802.11p OFDM modulation used for DSRC communications. A test statistic will be given that is invariant to the signal noise covariance to …
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Cyclostationary Random Vibration of a Ship Propeller and a Road Vehicle
… with periodically varying statistics, called cyclostationary (CS), is investigated. These processes are encountered in many engineering problems involving rotating machinery such as turbines, propellers, helicopter rotors, and diesel engines. We analyze a cyclostationary process model in order …
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Second-order Cyclostationary Feature Based Detection of WiMAX Signals in Pulsed Noise Environments
… for wireless broadband systems is evaluated. Cyclostationary feature based detection methods are evaluated against gaussian noise and interfering radar signals. Alternative decision algorithms utilizing support vector machines are proposed and evaluated and compared against traditional general …
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Multitaper Methods for Cyclostationary Feature Detection in Time Series Data: Application to ACE Interplanetary Magnetic Field Data
… thesis, a deeper understanding of the theory of cyclostationary processes is sought. Conventional spectrum estimation techniques assume that the data is a realization of a stationary process. If the data is cyclostationary, standard methodology, which assumes stationarity and so autocovariances …
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Shipboard Fault Detection Methods for Condition-based Maintenance
… spectral coherence to identify subtle shifts in cyclostationary behavior provide new opportunities in vibration-based monitoring. The acquisition of vibration measurements must overcome significant practical challenges for successful vibration analysis. This work demonstrates vibration analysis …
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A CMA-FRESH Whitening Filter for Blind Interference Rejection
… present a method for interference rejection of cyclostationary signals, which can also help avoid interference through better detection of low power co-channel signals. The method proposed in this thesis consists of a frequency-shift (FRESH) filter which acts as a whitening filter, canceling the …
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Advanced classification of OFDM and MIMO signals with enhanced second order cyclostationarity detection
… and improved. Based on the fact that most of the cyclostationary communication signals has a real cyclostationary part and a complex non-cyclostaionary part, we suggest an approach that enhance the second order cyclostationarity and hence increase its probability of detection. Using such improved …
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Software Radio-Based Decentralized Dynamic Spectrum Access Networks: A Prototype Design and Enabling Technologies
… all possible conditions is challenging. The cyclostationary feature detection method is attractive for detecting primary users because of its ability to distinguish between modulated signals, interference, and noise at a low signal-to-noise ratio (SNR). However, a key issue of cyclostationary …
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Study of the Kalman filter for arrhythmia detection with intracardiac electrograms
… with the use of Kalman filter applied on cyclostationary autoregressive model. This new algorithm was developed with a training set of 24 arrhythmia passages and tested on a different data set of 29 arrhythmia passages. The algorithm provides 100% detection of VF on the test set. 77.8% of …
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Blind adaptive antenna arrays for mobile communications
… as a new blind algorithm that exploits the cyclostationary property of the signal. Results show that the TDAA is able to out-perform the other blind algorithms for most of the test conditions and provides the optimal MSE solution.
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Wideband Spectrum Sensing and Signal Classification for Autonomous Self-Learning Cognitive Radios
… spectrum sensing method based on joint energy/cyclostationary detection. Optimal wideband energy detector is designed based on the Neyman-Pearson (NP) criterion which maximizes the detection probability of primary signals, subject to a certain false alarm rate. Cyclostationary detection is …
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AMPS co-channel interference rejection techniques and their impact on system capacity
… NAMPS signals. A mathematical analysis of the cyclostationary features of AMPS and NAMPS signals is presented to help explain and analyze these techniques. Their performance is investigated using both simulated and digitized data. The impact of these new techniques on AMPS system capacity is …
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The Role of diapycnal mixing in coupled atmosphere-ocean general circulation models
… an unrealistic<br/>high value of 5 cm2/s. At the cyclostationary state, global MOC strength is found to scale with v<br/>(in agreement with previous studies) according to a power law of 0.5. No power law is found for the<br/>MOC in the individual basins. The increase in MOC strength in the …
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The dual-polarization radar signature of a wind turbine: characterization and suppression
… to mitigate wind turbine clutter. Using the cyclostationary characteristics, 15-20 dB of suppression of the turbine blades' signature is demonstrated. A field experiment that simultaneously collected radar observations of a wind turbine and turbine state telemetry is also discussed in this …
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Diagnostics for Periodically Operated Actuators
… and monitoring of critical industrial equipment. Cyclostationary analysis enables diagnostics based on signals with strong random components by extracting modulation signatures otherwise unattainable by conventional time or frequency domain analysis, as demonstrated with applications to diaphragm …
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