2. QUADRATIC TIME-FREQUENCY DISTRIBUTIONS AND AMBIGUITY FUNCTION In this paper, the properties Of the recently Proposed B-distribution are investigated. We show that this distribution satisfies most of the desirable properties sought for a time-frequency distribution. Quadratic (also known as Cohen’s) class of time-frequency distributions is defined by the following expression [31: That is, we ...

Although traditional signal-based structural health monitoring algorithms have been successfully employed for small structures, their application for large and complex bridges has been challenging due to non-stationary signal characteristics with a high level of noise. In this paper, a promising damage detection algorithm is proposed by incorporation of adaptive signal processing and Artificial...

The record of human brain neural activities, namely electroencephalogram (EEG), is generally known as a non-stationary and nonlinear signal. In many applications, it is useful to divide the EEGs into segments within which the signals can be considered stationary. Combination of empirical mode decomposition (EMD) and Hilbert transform, called Hilbert-Huang transform (HHT), is a new and powerful ...

Given a unitary operator A representing a physical quantity of interest, we employ concepts from group representation theory to define two natural signal energy densities for A. The first is invariant to A and proves useful when the effect of A is to be ignored; the second is covariant to A and measures the “A” content of signals. We also consider joint densities for multiple operators and, in ...

Article history: Available online 18 May 2012