| Probability Density Function Method for Observing Reconstructed Attractor Structure |
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| 作者姓名： | 陆宏伟 陈亚珠 卫青 |
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| 作者单位： | [1]BiomedicalInstrumentInstitute,ShanghaiJiaotongUniversity,Shanghai200030,P.R.China [2]RadiophysicsLab,PhysicsDepartment,CollegeofSciences,ShanghaiUniversity,Shanghai200436,P.R.China |
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| 基金项目： | theScienceFoundationofShanghaiMunicipalCommissionofScienceandTechnology (GrantNo .9944 190 2 7) |
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| 摘 要： | Probability density function (PDF) method is proposed for analysing the structure of the reconstructed attractor in computing the correlation dimensions of RR intervals of ten normal old men. PDF contains important information about the spatial distribution of the phase points in the reconstructed attractor. To the best of our knowledge, it is the first time that the PDF method is put forward for the analysis of the reconstructed attractor structure. Numerical simulations demonstrate that the cardiac systems of healthy old men are about 6 - 6.5 dimensional complex dynamical systems. It is found that PDF is not symmetrically distributed when time delay is small, while PDF satisfies Gaussian distribution when time delay is big enough. A cluster effect mechanism is presented to explain this phenomenon. By studying the shape of PDFs, that the roles played by time delay are more important than embedding dimension in the reconstruction is clearly indicated. Results have demonstrated that the PDF method represents a promising numerical approach for the observation of the reconstructed attractor structure and may provide more information and new diagnostic potential of the analyzed cardiac system.
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| 关 键 词： | 概率密度函数法 PDF 数值模拟 心脏系统 老年人 疾病诊断 |
| 收稿时间： | 19 March 2003 |
Probability density function method for observing reconstructed attractor structure |
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| Lu?Hong-wei,Chen?Ya-zhu,Wei?Qing.Probability Density Function Method for Observing Reconstructed Attractor Structure[J].Journal of Shanghai University(English Edition),2004,8(1):75-79. |
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| Authors: | Lu Hong-wei Chen Ya-zhu Wei Qing |
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| Institution: | (1) Biomedical Instrument Institute, Shanghai Jiaotong University, 200030 Shanghai, P.R. China;(2) Radiophysics Lab, Physics Department, College of Sciences, Shanghai University, 200436 Shanghai, P.R. China |
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| Abstract: | Probability density function (PDF) method is proposed for analysing the structure of the reconstructed attractor in computing the correlation dimensions of RR intervals of ten normal old men. PDF contains important information about the spatial distribution of the phase points in the reconstructed attractor. To the best of our knowledge, it is the first time that the PDF method is put forward for the analysis of the reconstructed attractor structure. Numerical simulations demonstrate that the cardiac systems of healthy old men are about 6-6.5 dimensional complex dynamical systems. It is found that PDF is not symmetrically distributed when time delay is small, while PDF satisfies Gaussian distribution when time delay is big enough. A cluster effect mechanism is presented to explain this phenomenon. By studying the shape of PDFs, that the roles played by time delay are more important than embedding dimension in the reconstruction is clearly indicated. Results have demonstrated that the PDF method represents a promising numerical approach for the observation of the reconstructed attractor structure and may provide more information and new diagnostic potential of the analyzed cardiac system. |
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| Keywords: | probability density function (PDF) RR intervals correlation dimension (CD) phase space reconstruction chaos |
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