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Biomedical subjects

T Stanford

Publications and source records attributed to T Stanford.

6 recordsLinked to original sources
PubMed2000

Validity of threshold-crossing analysis of symbolic dynamics from chaotic time series

A practical and popular technique to extract the symbolic dynamics from experimentally measured chaotic time series is the threshold-crossing method, by which an arbitrary partition is utilized for determining the symbols. We address to what extent the symbolic dynamics so obtained can faithfully represent the phase-space dynamics. Our principal result is that such a practice can lead to a severe misrepresentation of the dynamical system. The measured topological entropy is a Devil's staircase-like, but surprisingly nonmonotone, function of a parameter characterizing the amount of misplacement of the partition.

Journal Article↗
PubMed1984

Configuration color vision tests: the interaction between aging and the complexity of figure-ground segregation.

A cross-sectional study comparing response time and the percentage of items correctly identified in three color vision tests (Pflügertrident, HRR-AO pseudoisochromatic plates, and AO pseudoisochromatic plates) was carried out on 72 women (12 in each decade) ranging from ages 20 to 79 years. Overall, time scores increased across the age groups. Analysis of the correctness scores indicated that the AO pseudoisochromatic plates requiring the identification of numbers was more difficult than the other tests which consisted of geometric forms or the letter E. This differential difficulty increased as a function of age. There was no indication of color defect per se which led to the conclusion that figure complexity may be the key variable determining performance. The results were similar to those obtained by Lee and Pollack (1978) in their study of the Embedded Figures Test.

Adult↗