Introduction High intensity focused ultrasound (HIFU) is considered a noninvasive and effective technique for tumor ablation. Frequency and acoustic power are the most effective parameters for temperature distribution and the extent of tissue damage. The aim of this study was to optimize the operating transducer parameters such as frequency and input power in order to acquire suitable temperatu...

Nonstationary ultrasound Doppler signals, those are changing with time and frequency simultaneously, are widely observed in biological and speech signals. A Cohen’s class timefrequency (TF) analysis can analyze nonstationary signals with high resolution in time and frequency at a same time. A time-frequency distribution (TFD) is largely affected by a kernel function. Thus, there is sometimes a ...

One of the applications with nonlinear nonstationary signals lies in mobile communications where nonlinear information bearing signals are faded by the time-varying propagation medium. Consequently, the envelope of the received signal is often modelled by a Rayleigh distribution. This Rayleigh fading severely degrades the performance of the mobile radio transmission system. Diversity reception ...

New generations of spark ignition engines require a correct ignition adjustment to guarantee optimal performance. In this paper, we address the challenge of knock detection improvements with time-frequency analysis. Two real time knock detection methodologies based on the sliding Discrete Fourier Transform and the pseudo Wigner-Ville distribution are exposed. Their relative performances and rob...

Time-frequency distributions (TFD’s), which indicate the energy content of a signal as a function of both time and frequency, are powerful tools for time-varying signal analysis. The lack of a single distribution that is “best” for all applications has resulted in a proliferation of TFD’s, each corresponding to a different, fixed mapping from signals to the time-frequency plane. A major drawbac...

16 17 We have studied the relationships between present day relief, precipitation, stream power, 18 seismic energy, seismic strain rate and long-term exhumation rates for the Venezuelan Andes. 19 Average long-term exhumation rates were determined for seven large catchments in the 20 Venezuelan Andes from fission-track analysis of detrital apatite. A quantitative comparison 21 between eight new ...