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.
Results
Showing 1 to 13 of 13 for “"Time-frequency Representations"”.
-
Shear Madness: Signal-Dependent and Metaplectic Time-Frequency Representations
Time-frequency representations are multidimensional transformations that indicate the joint time-frequency content of a signal. Representations such as the wavelet transform, the short-time Fourier transform, and the Wigner distribution have proven to be powerful tools for signal analysis and …
-
Statistical time-frequency analysis
Time-frequency representations (TFRs), such as the short-time Fourier transform, the wavelet transform, and the Wigner distribution, represent signal characteristics jointly in time and frequency and provide a versatile set of tools for the analysis and processing of nonstationary signals. Recent …
-
Exploiting pitch dynamics for speech spectral estimation using a two-dimensional processing framework
… the voicing source exhibits a high fundamental frequency. Our work is inspired by auditory perception and physiological modeling studies implicating the use of temporal changes in speech by humans. Specifically, we develop and evaluate signal processing schemes that exploit temporal change of …
-
Discovering Power System Dynamics through Time-Frequency Representation of Ambient Data
… exclusively to construct spectrograms, which are time-frequency representations of a signal's spectral information. These spectrograms show ridges that represent the system's changing modes. It can be extremely beneficial to track these modes and generate labeled data representing the evolution of …
-
Location Finding in Natural Environments with Biomimetic Sonar and Deep Learning
… is about 6 meters of radius resolution. The time- frequency representations of echoes from the forest are used as input data to explore the biosonar navigation ability, and the state-of-the-art CNN deep network (Resnet 152) is used as the brain to do the echolocation in the dense forest. The …
-
Early detection, classification and proactive mitigation of cyberattacks in microgrids embedded with renewables and electric vehicles charging infrastructure
… (CWT), which converts input signals into time–frequency representations called scalograms. These scalograms accurately visualize and highlight sharp transition events, making them an effective tool for capturing anomalies indicative of cyberattacks. These scalograms are further enhanced …
-
Radar intra-pulse modulation classification using convolutional neural networks
… of real-world scenarios as possible. Data representations of varying levels of abstraction were analysed in order to investigate the effects of data formatting on the performance of various classifiers. A classifier which made use of manual feature extraction was evaluated against a series …
-
Analysis and filtering of time-varying signals
… analysis and filtering of a slowly time-varying (STV) deterministic signal are considered. A STV signal is characterized as a sophisticated signal whose windowed sections are elementary signals. Mixed time-frequency representations (MTFRs) such as the Wigner distribution (WD), the …
-
Acoustic Seabed and Target Classification using Fractional Fourier Transform and Time-Frequency Transform Techniques
… magnitude of the bottom impulse response. Joint time-frequency representations of the signal offer the possibility to determine the time-frequency configuration of the signal as its characteristic features for classification purposes. The classification is based on singular value decomposition of …
-
Implicit neural representations for time-frequency signal processing
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-20 without embargo terms
-
Time-frequency investigation of heart rate variability and cardiovascular system modeling of normal and chronic obstructive pulmonary disease (COPD) subjects
… the applications of five different bilinear time-frequency representations are evaluated on modeled HRV test signals, actual electrocardiograms (ECG), BP and RESP signals. Each distribution: the short time Fourier transform (STFT), the smoothed pseudo Wigner-Ville (SPWVD), the ChoiWilliams …
-
High-resolution sinusoidal analysis for resolving harmonic collisions in music audio signal processing
… However, due to resolution limits inherent in time-frequency analyses, when the harmonics of multiple sources occupy equivalent time-frequency regions, their individual properties are additively combined in the time-frequency representation of the mixed signal. Any such time-frequency point in …
-
Discerning nonlinear brain dynamics from EEG : an application to autistic spectrum disorder in young children
… based on the analysis of multi-probe EEG time-series from male children aged 3-5 years. The methods applied are all ones that take explicit account of the intrinsically non-linear, open, and time-variable nature of the system. Time-frequency representations were first computed from the …