Series Fluctuation
fluctuation
Measures the proportion of large changes in the time-series.
Low value: Means few/none large fluctuations.
High value: Means many large fluctuations.
No Parameters
Calculation
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Z-Normalization: First, the time series Yt is z-normalized.
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Successive Differences: Then the absolute differences between consecutive values of the z-normalized series are calculated.
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Thresholding and Counting: The counting of the number of absolute differences that are greater than a defined threshold (0.04) is computed.
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Proportion: The final value, which is returned, is the proportion of such differences.
Practical Usefulness Examples
Financial Market Volatility: In analyzing stock price differences, a high value might indicate a "jumpy" market with frequent large price changes over short intervals, signaling higher risk or specific trading conditions.
Wearable Health Monitoring: For activity data from a wearable, a higher value could distinguish between smooth, consistent activity and erratic, stop-and-go movements.