CWI's research has a theme-oriented structure and is grouped into four clusters. Listed below are the names of the clusters and in parentheses their acronyms. 1. INTRODUCTION A feature of a seismic earthquake signal is that it is built up by several different seismic waves, characterizing the type of signal. In this paper we are only interested in two of these waves, namely the primary wave (P-...

The presentation concerns a method for tracking cycle lengths in voiced speech and analysing vocal cycle lengh fluctuations. The tracking of cycle lengths is based on a dynamic programming algorithm, which does not request that the signal is locally periodic and the average period length is known a priori. The obtained cycle length time series is then decomposed into a sum of intrinsic mode fun...

This paper describes a method of signal process applied on an end effects of Hilbert-Huang transform (HHT) to provide an improvement in the reality of spectrum. The method is based on back-propagation network (BPN). To improve the effect, the end extension of the original signal is obtained by back-propagation network. A full waveform including origin and its extension is decomposed by using em...

Based on 56 rainfall stations, which cover the period 1961–2008, we analyzed the presence of trends in the drought-affected area over southern South America (SSA) at different time scales. In order to define drought conditions, we used the standardized precipitation index, which was calculated on time scales of 1, 3, 6, 9 and 12 months. The trends were estimated following both a linear and a no...

Measurement of pipeline wall thickness is one of the main contents of nondestructive inspection on offshore oil pipeline. A novel approach based on the marginal spectrum of the Hilbert-Huang transform is proposed for ultrasonic echo signal processing. The demodulated ultrasonic echo signal contains the thickness information of pipeline wall, which is an approximately periodic signal. The margin...

Failure detection has always been a demanding task in the electrical machines community; it has become more challenging in wind energy conversion systems because sustainability and viability of wind farms are highly dependent on the reduction of the operational and maintenance costs. Indeed the most efficient way of reducing these costs would be to continuously monitor the condition of these sy...

[1] Data analysis has been one of the core activities in scientific research, but limited by the availability of analysis methods in the past, data analysis was often relegated to data processing. To accommodate the variety of data generated by nonlinear and nonstationary processes in nature, the analysis method would have to be adaptive. Hilbert-Huang transform, consisting of empirical mode de...

Cepstral-based acoustic cues for disordered voices analysis have been investigated in a number of studies. It has been shown that cepstral-based acoustic cues such as the harmonics-to-noise ratio (HNR), the amplitude of the first rhamonic (R1A) provide acoustic correlates for hoarse voice quality. The aim of this presentation is to investigate an acoustic analysis of speech by means of spectral...

The ever-increasing air traffic demand in China has brought huge pressure on the planning and management of, and investment in, air terminals as well as airline companies. In this context, accurate and adequate short-term air traffic forecasting is essential for the operations of those entities. In consideration of such a problem, a hybrid air traffic forecasting model based on empirical mode d...

This paper introduces a new instantaneous frequency computation approach -Counting Instantaneous Frequency for a general class of signals called simple waves. The classsimple wave contains a wide range of continuous signals for which the concept instantaneous frequency has a perfect physical sense. The concept of -Counting Instantaneous Frequency also applies to all the discrete data. For all t...