IoTDB-Quality

# MissDetect

# Usage

This function is used to detect missing anomalies. In some datasets, missing values are filled by linear interpolation. Thus, there are several long perfect linear segments. By discovering these perfect linear segments, missing anomalies are detected.

Name: MISSDETECT

Input Series: Only support a single input series. The data type is INT32 / INT64 / FLOAT / DOUBLE.

Parameter:

error: The minimum length of the detected missing anomalies, which is an integer greater than or equal to 10. By default, it is 10.

Output Series: Output a single series. The type is BOOLEAN. Each data point which is miss anomaly will be labeled as true.

# Examples

Input series:

+-----------------------------+---------------+
|                         Time|root.test.d2.s2|
+-----------------------------+---------------+
|2021-07-01T12:00:00.000+08:00|            0.0|
|2021-07-01T12:00:01.000+08:00|            1.0|
|2021-07-01T12:00:02.000+08:00|            0.0|
|2021-07-01T12:00:03.000+08:00|            1.0|
|2021-07-01T12:00:04.000+08:00|            0.0|
|2021-07-01T12:00:05.000+08:00|            0.0|
|2021-07-01T12:00:06.000+08:00|            0.0|
|2021-07-01T12:00:07.000+08:00|            0.0|
|2021-07-01T12:00:08.000+08:00|            0.0|
|2021-07-01T12:00:09.000+08:00|            0.0|
|2021-07-01T12:00:10.000+08:00|            0.0|
|2021-07-01T12:00:11.000+08:00|            0.0|
|2021-07-01T12:00:12.000+08:00|            0.0|
|2021-07-01T12:00:13.000+08:00|            0.0|
|2021-07-01T12:00:14.000+08:00|            0.0|
|2021-07-01T12:00:15.000+08:00|            0.0|
|2021-07-01T12:00:16.000+08:00|            1.0|
|2021-07-01T12:00:17.000+08:00|            0.0|
|2021-07-01T12:00:18.000+08:00|            1.0|
|2021-07-01T12:00:19.000+08:00|            0.0|
|2021-07-01T12:00:20.000+08:00|            1.0|
+-----------------------------+---------------+

SQL for query:

select missdetect(s2,'minlen'='10') from root.test.d2

Output series:

+-----------------------------+------------------------------------------+
|                         Time|missdetect(root.test.d2.s2, "minlen"="10")|
+-----------------------------+------------------------------------------+
|2021-07-01T12:00:00.000+08:00|                                     false|
|2021-07-01T12:00:01.000+08:00|                                     false|
|2021-07-01T12:00:02.000+08:00|                                     false|
|2021-07-01T12:00:03.000+08:00|                                     false|
|2021-07-01T12:00:04.000+08:00|                                      true|
|2021-07-01T12:00:05.000+08:00|                                      true|
|2021-07-01T12:00:06.000+08:00|                                      true|
|2021-07-01T12:00:07.000+08:00|                                      true|
|2021-07-01T12:00:08.000+08:00|                                      true|
|2021-07-01T12:00:09.000+08:00|                                      true|
|2021-07-01T12:00:10.000+08:00|                                      true|
|2021-07-01T12:00:11.000+08:00|                                      true|
|2021-07-01T12:00:12.000+08:00|                                      true|
|2021-07-01T12:00:13.000+08:00|                                      true|
|2021-07-01T12:00:14.000+08:00|                                      true|
|2021-07-01T12:00:15.000+08:00|                                      true|
|2021-07-01T12:00:16.000+08:00|                                     false|
|2021-07-01T12:00:17.000+08:00|                                     false|
|2021-07-01T12:00:18.000+08:00|                                     false|
|2021-07-01T12:00:19.000+08:00|                                     false|
|2021-07-01T12:00:20.000+08:00|                                     false|
+-----------------------------+------------------------------------------+

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