A review on empirical mode decomposition in fault diagnosis of rotating machinery

Computational and Mathematical Methods in Medicine

The field of electrocardiography has been in existence for over a century, yet despite significant advances in adult clinical electrocardiography, signal processing techniques and fast digital processors, the analysis of fetal ECGs is still in its infancy. This is, partly due to a lack of availability of gold standard databases, partly due to the relatively low signal-to-noise ratio of the fetal ECG compared to the maternal ECG (caused by the various media between the fetal heart and the measuring electrodes, and the fact that the fetal heart is simply smaller), and in part, due to the less complete clinical knowledge concerning fetal cardiac function and development. In this paper we review a range of promising recording and signal processing techniques for fetal ECG analysis that have been developed over the last forty years, and discuss both their shortcomings and advantages. Before doing so, however, we review fetal cardiac development, and the etiology of the fetal ECG. A selection of relevant models for the fetal/maternal ECG mixture is also discussed. In light of current understanding of the fetal ECG, we then attempt to justify recommendations for promising future directions in signal processing, and database creation.

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A Review of Fetal ECG Signal Processing; Issues and Promising Directions.

Introduces nonstationary signal analysis methods to analyze the myoelectric (ME) signals during dynamic contractions by estimating the time-dependent spectral moments. The time-frequency analysis methods including the short-time Fourier transform, the Wigner-Ville distribution, the Choi-Williams distribution, and the continuous wavelet transform were compared for estimation accuracy and precision on synthesized and real ME signals. It is found that the estimates provided by the continuous wavelet transform have better accuracy and precision than those obtained with the other time-frequency analysis methods on simulated data sets. In addition, ME signals from four subjects during three different tests (maximum static voluntary contraction, ramp contraction, and repeated isokinetic contractions) were also examined.

Time-frequency analysis of myoelectric signals during dynamic contractions: a comparative study

Uterine electromyography: A critical review

This article proposes a method to evaluate the ability of the electrohysterogram signal to characterize the contractions during pregnancy, in a population with high risk of preterm deliveries. This study constitutes a first stage of a project intended to develop a monitoring system for the early diagnosis of preterm deliveries. After a proper signal denoising, the authors calculate some parameters characteristic of the extracted contractions. These contractions are then divided into classes of different physiological terms. Classical techniques of data analysis, such as principal component analysis and discriminant analysis, permit the authors to show an evolution of the contractions during pregnancy, which is different between the groups of preterm deliveries and that of deliveries at term. The authors show that, in an early term of pregnancy, they can separate the two populations: women delivering at term from women delivering preterm. The authors then show that these two kinds of pregnancy are of different evolutions. These results are encouraging, because they would permit, in a follow-up medical study, to diagnose a possible preterm delivery, as well as the proximity of the delivery.

Use of the electrohysterogram signal for characterization of contractions during pregnancy

The temporal and spectral properties of the human uterine electromyogram are first described, related to two different situations: pregnancy and parturition. Thus, a parameter set is selected, and a discriminant analysis is performed, in order to obtain the best discriminant vector for these two situations. A dynamic control of the efficiency of the contractions during labor is described. The good results of this dynamic control permit us to propose a monitoring device providing information on contraction rate and efficiency.

Uterine EHG Processing for Obstetrical Monitorng

A quarter of a century ago, in the preface to Brain Mechanisms in Sensory« Substitution », Paul Bach y Rita wrote: "This monograph thus risks becoming outdated in a very short time since the development of refined sensory substitution systems should allow many of the question raised here to be answered, and some of the conclusions may appear naive to future readers." (BACH Y RITA, 1972) As it turns out, this prediction is far from having been fulfilled: in spite of their scientific and social interest, their real effectiveness and a certain technological development, prosthetic devices employing the principle of "sensory substitution" are not widely used by the blind persons for whom they were originally destined. After a brief recall of the general principle of sensory substitution, we will advance several hypotheses to account for this situation. We will then identify some elements which may favour the conception and, especially, the usability of future devices. To this end, we will focus our analysis on the work of Bach-y-Rita, particularly well documented, devoted to TVSS (Tactile Vision Sensory Substitution) since the 1960's. This choice is motivated by the extensive and exemplary nature of this research, devoted to the rehabilitation of a handicapped population, as an enterprise which is both technical and scientific in character. We will also present the specific interest of substitution systems employing tactile stimulation, and we will emphasize the essential coordination of fundamental and technological research in this area. In addition, besides their direct utility for handicapped persons, these devices open broad experimental and theoretical perspectives on cognition in general (brain plasticity, perception, intentionality, etc....)

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Sensory substitution: limits and perspectives

Background
The electrical activity of the uterine muscle is representative of uterine contractility. Its characterization may be used to detect a potential risk of preterm delivery in women, even at an early gestational stage.

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Catherine Marque

Papers

Uterine electromyography: A critical review

Use of the electrohysterogram signal for characterization of contractions during pregnancy

Uterine EHG Processing for Obstetrical Monitorng

Sensory substitution: limits and perspectives

Preterm labour detection by use of a biophysical marker: the uterine electrical activity