Title :
Correlation dimension estimation: can this nonlinear description contribute to the characterization of blood pressure control in rats?
Author :
Almog, Yael ; Oz, Orna ; Akselrod, Solange
Author_Institution :
Sch. of Phys. & Astron., Tel Aviv Univ., Israel
fDate :
5/1/1999 12:00:00 AM
Abstract :
The application of correlation dimension estimation to the study of cardiovascular control, via the blood pressure (BP) time series was investigated. The authors chose to calculate the Grassberger-Procaccia (GP) correlation dimension. In order to obtain a reliable estimate of the correlation dimension, they studied impact of various parameters such as the appropriate sampling rate, the time delays, the embedding dimension, the minimal trace length required, and the number of points needed as reference points. The authors developed a recipe for the reliable treatment of the continuous BP signal in rats, their animal model, and discussed the possible pitfalls which demand special attention. Next, they applied the surrogate data method to a BP time series, looking for the existence of nonlinear components, in order to test whether the nonlinear modeling is necessary for accurately describing the system. The authors found that, indeed, the correlation dimension does reveal information which cannot be unveiled by the commonly used power spectral technique, thus, making the nonlinear modeling an important approach, providing additional insight into the cardiovascular control system.
Keywords :
biocontrol; haemodynamics; physiological models; pressure control; time series; animal model; appropriate sampling rate; blood pressure control characterization; cardiovascular control system; correlation dimension estimation; embedding dimension; minimal trace length required; nonlinear components; nonlinear description; nonlinear modeling; rats; reference points number needed; surrogate data method; time delays; Animals; Blood pressure; Cardiology; Delay effects; Delay estimation; Power system modeling; Pressure control; Rats; Sampling methods; System testing; Algorithms; Animals; Blood Pressure; Blood Pressure Determination; Female; Hypertension; Male; Models, Cardiovascular; Nonlinear Dynamics; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Signal Processing, Computer-Assisted;
Journal_Title :
Biomedical Engineering, IEEE Transactions on