3 citations · 6 across the 2 of their papers we have counts for
4 papers
Non-linear and scale-invariant analysis of the Heart Rate Variability
J. Kalda, M. Sakki, M. Vainu +1
Human heart rate fluctuates in a complex and non-stationary manner. Elaborating efficient and adequate tools for the analysis of such signals has been a great challenge for the res…
Oceanic coastline and super-universality of percolation clusters
Jaan Kalda
New fractal subset of a rough surface, the ``oceanic coastline'', is defined. For random Gaussian surfaces with negative Hurst exponent , ``oceanic coastlines'' are mapped to…
What does the correlation dimension of the human heart rate measure?
M. Sakki, J. Kalda, M. Vainu +1
It is shown that in the case of human heart rate, the scaling behaviour of the correlation sum (calculated by the Grassberger-Procaccia algorithm) is a result of the interplay of v…
Zipf's law in human heartbeat dynamics
J. Kalda, M. Sakki, M. Vainu +1
It is shown that the distribution of low variability periods in the activity of human heart rate typically follows a multi-scaling Zipf's law. The presence or failure of a power la…