Comment on "Linguistic analysis of the human heartbeat using frequency and rank order statistics".
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Algorithms↗
Biomedical subjects
Walter Nadler
Publications and source records attributed to Walter Nadler.
Growth-based optimization algorithm for lattice heteropolymers.
An improved version of the pruned-enriched-Rosenbluth method (PERM) is proposed and tested on finding lowest energy states in simple models of lattice heteropolymers. It is found to outperform not only the previous version of PERM, but also all other fully blind general purpose stochastic algorithms which have been employed on this problem. In many cases, it found new lowest energy states missed in previous papers. Limitations are discussed.
Journal Article↗
Heat conduction and entropy production in a one-dimensional hard-particle gas.
We present large scale simulations for a one-dimensional chain of hard-point particles with alternating masses and correct several claims in recent literature based on much smaller simulations. We find heat conductivities kappa to diverge with the number N of particles. These depended strongly on the mass ratio, and extrapolations to N--> infinity, and t--> infinity, are difficult due to very large finite-size and finite-time corrections. Nevertheless, our data seem compatible with a universal power law kappa approximately N(alpha) with alpha approximately 0.33 suggesting a relation to the Kardar-Parisi-Zhang model. We finally discuss why the system leads nevertheless to energy dissipation and entropy production, in spite of not being chaotic in the usual sense.
Journal Article↗
Spin dephasing in the extended strong collision approximation.
For Markovian dynamics of field fluctuations we present here an extended strong collision approximation, thereby putting our previous strong collision approach [Phys. Rev. Lett. 83, 4215 (1999)]) into a systematic framework. Our approach provides expressions for the free induction and spin-echo magnetization decays that may be solved analytically or at least numerically. It is tested for the generic cases of dephasing due to an Anderson-Weiss process and due to restricted diffusion in a linear field gradient.
Journal Article↗