Evaluation of Mindful Breathing Method Using Tablet Devices Through Chaos Analysis and Frequency Analysis: A Pilot Randomized Controlled Trial

Figures

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  Figure 1.. Experimental configuration. Fixed-point measurement: measurement in the university laboratory; daily measurement: measurement at home; Mi: mindfulness group; nMi: nonmindfulness group. Validation: Mi group used a tablet device to practice mindful breathing; nMi group focused on the cross on the tablet device.

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  Figure 2.. Index of finger plethysmogram. Pulse wave amplitude is defined as the vertical distance between the systolic peak (point b) and the adjacent baseline trough (point a or e). This index reflects the change in blood volume in the fingertip during a single pulse cycle.

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  Figure 3.. Overview of calculating the fractal dimension. (a) Overview of the correlation diagram showing the relationship between log r and log C(r). The dashed box indicates the scaling domain, where the linear slope represents the correlation dimension for each embedding dimension. (b) Overview of the convergence diagram showing the slope ν as a function of embedding dimension D. The region of interest (D = 5 − 9) indicates the saturation region where ν stabilizes to define the final correlation dimension.

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  Figure 4.. Results of multiple comparisons of pulse wave amplitude values. Mean pulse wave amplitude [mV] in the mindfulness implementation group (Mi) and control group (nMi) at the fixed-point measurement and daily measurements on Day 1 and Day 9. Error bars represent standard deviations (N = 18 per group). **P < .01 by one-way ANOVA with Games–Howell post-hoc tests and Bonferroni correction.

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  Figure 5.. An example of the Lyapunov exponent. The plot shows the dynamic evolution of the Lyapunov spectrum (λ1, λ2, λ3, and λ4) as a function of the number of computation steps. While the final maximum Lyapunov exponent (λ1) is determined to be 1.75 (the average value at the end of the time series), the vertical axis shows the range of transient fluctuations during the initial stages of the calculation, with an observed maximum of 22.18 and a minimum of −55.05.

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  Figure 6.. Example of fractal dimension calculation results. (a) Correlation diagram showing the relationship between log r and log C(r) (correlation integral). The dashed box indicates the scaling domain, where the linear slope represents the correlation dimension. (b) Convergence diagram showing the slope ν as a function of embedding dimension D. The region of interest (D = 5 − 9) indicates the saturation region where ν stabilizes and defines the final correlation dimension.