Histogram summaries of the nine Summary Statistics across the Million Song Dataset (<i>N</i> = 971,278), using log₂ scaling along the <i>y</i>-axis to enhance visibility.

<p>Labels “A” through “I” correspond to the order in which Summary Statistics were defined in Section E of the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110452#s2" target="_blank">Methods</a>.</p

Pairwise scatter plot relationships (with associated Spearman correlation ρ values) for three BEATS Summary Statistics that quantify the stability of an IBeI series: PDL_max, SPC_max, and PTD_max.

<p>Pairwise scatter plot relationships (with associated Spearman correlation ρ values) for three BEATS Summary Statistics that quantify the stability of an IBeI series: PDL_max, SPC_max, and PTD_max.</p

The iBEATS website (http://ibeats.smcnus.org/).

<p>The nine Summary Statistics are visualized using histograms (1). The user queries iBEATS by adjusting the numeric thresholds, browsing a two-level hierarchy of <i>Genre/Style</i> and <i>Geography</i> terms (2), and/or direct input to the <i>Artist Name</i> field (3). Filtering (4) reveals the number of candidate songs satisfying the query, which may then be further examined (5) and an audio sample previewed (6). The candidate playlist may then be exported (7) for subsequent use by a streaming music service (e.g., Spotify).</p

Illustrating the relationship between three measures of temporal instability.

<p>Two permutations of the same set of IBeIs are presented; both have identical central tendency and PDL_max statistics. The IBeI series in (A) exhibits temporal dependency, with gradual transitions from IBeI to IBeI. The IBeI series in (B) exhibits a more stochastic pattern of IBeI transitions. These differences in temporal structure are reflected in the SPC_max and PTD_max statistics.</p

The 20 most frequent artist_terms included in the Million Song Dataset.

<p>The 20 most frequent artist_terms included in the Million Song Dataset.</p

Four examples from the MSD illustrating the calculated Summary Statistics.

<p>IBeIs (<i>y</i>-axis) are plotted as a function of real time (<i>x</i>-axis). The central tendency (λ) of each IBeI distribution is obtained via adaptive KDE (right subpanel), plotted in blue. Slopes used to calculate PTD_max statistics are highlighted in red. The final Stable Segment (bridged across Gaps) is highlighted in green circles. Spotify URLs can be suffixed to <a href="https://play.spotify.com/track/" target="_blank">https://play.spotify.com/track/</a> for listening.</p

Illustrating different central tendency statistics.

<p>(A) A hypothetical IBeI series comprised of three distinct tempo sections: 20 IBeIs with a mean of 0.5 s (i.e., 120 bpm), followed by 20 IBeIs with a mean of 0.75 s (80 bpm), followed by 40 IBeIs with a mean of 1.00 s (60 bpm). The mean, median, and mode of the data fail to provide an adequate measure of central tendency. (B) Kernel density estimation (KDE) of the distribution of IBeI values in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110452#pone-0110452-g001" target="_blank">Figure 1A</a>, using various bandwidth values. The most accurate measure of central tendency was obtained using adaptive Gaussian KDE <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110452#pone.0110452-Botev1" target="_blank">[90]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110452#pone.0110452-Botev2" target="_blank">[91]</a>.</p

Outcome measure results.

<p>Results of the <i>Group</i> (separate lines: PD vs. HE) × <i>Condition</i> (<i>x</i>-axis: self-paced, 100% RAC, 110% RAC) × <i>Device</i> (separate panels: SmartMOVE vs. heel contact–based) ANOVAs for step time (a.) and step length (b.) outcome measures.</p

Statistics associated with the <i>RAC</i> × <i>Device</i> ANOVA for step length outcome measures in PD patients.

<p>“SS” is the portioned sums of squares for each ANOVA term. Significant <i>p</i>-values are highlighted in bold.</p><p>Statistics associated with the <i>RAC</i> × <i>Device</i> ANOVA for step length outcome measures in PD patients.</p

Statistics associated with the <i>Group</i> × <i>Device</i> ANOVA for step time outcome measures during self-paced walking.

<p>“SS” is the portioned sums of squares for each ANOVA term. Significant <i>p</i>-values are highlighted in bold.</p><p>Statistics associated with the <i>Group</i> × <i>Device</i> ANOVA for step time outcome measures during self-paced walking.</p