We present two robust detectors for nonstationary random signals that belong to p-point uncertainty classes, one being based on an estimator-correlator approach, the other using the deflection criterion. Apart of stable performance, these robust detectors have the advantage of requiring only reduced prior knowledge. Using local cosine bases, we provide an intuitive and highly efficient timefreq...

This paper presents experimental results from the vibration of a polycarbonate beam containing a crack that opens and closes dudng vibration. Several techniques were employed to detect and locate the crack making use of the nonlinearity. “Harmonic mode shapes” proved to be more sensitive to damage than conventional mode shapes. Instantaneous f requency and timefrequency methods also showed clea...

Cohen’s class of time-frequency distributions for continuous signals has recently been to extended to discrete signals using both an axiomatic approach and an operator theory approach. In this paper, we investigate the formulation of several classical timefrequency distributions (Wigner, Rihaczek, Margenau-Hill, Page, Levin, Born-Jordan, spectrogram) in the discrete Cohen’s classes. The main re...

The proposed Georgia Institute of Technology (GIT) research effort will develop coherent space-timefrequency processing techniques to enhance the resonant acoustic signatures of man-made targets (e.g. elastic shells) recorded on various nodes of an autonomous distributed sensor network. Both the issues of 1) time-frequency shift of the acoustic signatures across the sensing aperture and 2) conv...

We propose a way to increase the speed of greedy pursuit algorithms for scalable sparse signal approximation. It is designed for dictionaries with localized atoms, such as timefrequency dictionaries. When applied to OMP, our modification leads to an approximation as good as OMP while keeping the computation time close to MP. Numerical experiments with a large audio signal show that, compared to...

This paper presents an emotion recognition system based on electroencephalography (EEG) signals. helps medical practitioners to analyse the mental health of individual. Eight healthy volunteers/ subjects had participated in this experiment. A specific feeling is evoked using particular songs and videos that are collected present before subjects. Total 6 emotions namely neutral, happy, sad, disg...

An efficient approach for instantaneous frequency (IF) rate estimation is proposed. It is based on a timefrequency rate representation with complex-lag argument. The proposed representation is derived in a manner to reduce the spread factor, and thus to provide high concentration along the IF rate. Due to the significantly reduced spread factor, it is suitable for periodically frequency modulat...

ELINT/ESM type of electronic intelligence in the primary layer uses parameters measurements of intercepted radar signals. Nowadays modern radar uses more and more complex waveforms. Some waveforms are developed intentionally to make their intercept almost impossible. The main distinctive features of modern radar signal are hidden in its time-frequency structure. In the near past the problem of ...

The cosine modulated filter bank is commonly used for the timefrequency decomposition of audio signals. For example, it is a basic element of the MPEG-1 and MPEG-2 audio coding standards. While this filter bank is not perfectly-reconstructing, it does provide for the cancelation of aliasing components that are introduced during the analysis decomposition. If the subband signals are to be proces...

We present a system for automatic arrhythmia detection and classification in ECGs. Arrhythmia detection is based on time and timefrequency domain features of heart rate variability. The RR interval duration signal is extracted from ECGs and segmented into small intervals. Time domain features are extracted and used for the training of a set of neural networks. Short time Fourier transform, and ...