**Periodic pattern mining** is a data mining technique used to discover **periodic patterns** in a **sequence of events**. Algorithms for periodic pattern mining have many applications. I have prepared **10 questions** to evaluate your knowledge of **periodic pattern mining**. You may answer them and then check the answers at the end of this post to verify your answers. Then, you may let me know how many good answers you got in the comment section. ðŸ˜‰

If you don’t know about this topic, you can check my introduction to periodic pattern mining and also my list of key papers on periodic pattern mining. And you may also find source code of fast implementations in the SPMF software.

## Questions

- What is the main goal of
**periodic pattern mining**? - What is the difference between
**periodic pattern mining**and**sequential pattern mining**? - What are some common applications of periodic pattern mining?
- What is the minimum support threshold in periodic pattern mining?
- What is the
**period length**in periodic pattern mining? - What is the
**PFPM**algorithm in periodic pattern mining? - What is a
**stable periodic pattern**? - What is the difference between exact and approximate periodic patterns?
- What is the difference between global and
**local periodic patterns**? - What are some challenges in periodic pattern mining?

## Answers

- The main goal of periodic pattern mining is to discover periodic patterns, that is events that are repeating over time more or less regularly in a sequence of events.
- Sequential pattern mining focuses on finding subsequences that are common to multiple sequences, while
**periodic pattern mining**focuses on finding repeating patterns within a single sequence of events. - Some common applications of
**periodic pattern mining**include stock market analysis, weather forecasting, customer behavior analysis, and bioinformatics. - The minimum support threshold is a user-defined parameter that specifies the minimum number of occurrences that a pattern must have in a sequence.
- The
**period length**is the length of time between repeating occurrences of a pattern in the input sequence. - The PFPM (Prefix-projected Frequent Pattern Mining) algorithm is an algorithm for discovering frequent periodic itemsets.
- A
**stable periodic pattern**is a pattern that occurs at regular intervals with little variability in a sequence of events. This is the opposite of an unstable pattern. Several algorithms exists for this such as TSPIN and LPP-Growth. - Exact periodic patterns have a fixed period length and occur at regular intervals, while approximate periodic patterns have some variability in their period length and occurrence.
- Global periodic patterns occur throughout the entire input sequence, while
**local periodic patterns**are patterns that have a periodic behavior only within some specific time intervals. - Some challenges in periodic pattern mining include handling large datasets, dealing with noise and missing data, and incorporating constraints.

Have you succeeded to answer all the questions? Let me know how you did in the comment section ðŸ˜‰

**Philippe Fournier-Viger** is a full professor working in China and founder of the **SPMF** open source data mining software.