We propose a new class of affine higher order time-frequency representations (HO-TFRs) unifying HO-TFRs which satisfy the desirable properties of scale covariance and time-shift covariance. This new class extends to higher order (N > 2) the affine class of quadratic (N = 2) time-frequency representations. In this paper, we provide five alternative formulations of the class in terms of multi-dim...

Recently we have proposed the T-class of time-frequency distributions (TFD’s) with time-only kernels to provide high-resolution and considerable cross-terms reduction for multicomponent FM signals. In this work we investigate the instantaneous frequency (IF) properties of two members of this class: the hyperbolic and the exponential T-distributions in the presence of noise. A comparison with tw...

On a suitable category of formal schemes equipped with codimension functions we construct a canonical pseudofunctor (−)♯ taking values in the corresponding categories of Cousin complexes. Cousin complexes on such a formal scheme X functorially represent derived-category objects F by the local cohomologies H codim(x) x F (x ∈ X) together with “residue maps” from the cohomology at x to that at ea...

background and purpose: the identification of genetics risk factors of human diseases is very important. this study is conducted to model the allele frequencies (afs) of alzheimer’s disease. materials and methods: in this study, several candidate probability distributions are fitted on a data set of alzheimer’s disease genetic risk factor. unknown parameters of the considered distributions are ...

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 ...

in this paper, a structural damage identification method (sdim) is developed for plate-like structures. this method is derived using dynamic equation of undamaged/damaged plate, in which local change in flexural rigidity is characterized utilizing a damage distribution function. the sdim requires to modal data in the intact state and frequency response of damage state where most of vibration ba...

Due to the non-stationary, multicomponent nature of biomedical signals, the use of time-frequency analysis can be inevitable for these signals. The choice of the proper time-frequency distribution (TFD) that can reveal the exact multicomponent structure of biological signals is vital in many applications, including the diagnosis of medical abnormalities. In this paper, the instantaneous frequen...

Efficient processing of nonstationary signals requires time-varying approach. An interesting research area within this approach is time-varying filtering. Since there is a certain amount of freedom in the definition of timevarying spectra, several definitions and solutions for the time-varying filtering have been proposed so far. Here we will consider the Wigner distribution based time-varying ...