| 摘要 |
PROBLEM TO BE SOLVED: To achieve appropriate extraction even if a percentage of the number of risk events in a pattern with a small number of items is small, when an event occurrence factor having a tendency of a more frequent occurrence is extracted to a greater degree than a combination of event occurrence factors having a tendency of a more frequent occurrence.SOLUTION: When the number of items in a combination pattern of event occurrence factors is two, if a ratio of a value corresponding to the pattern to a value corresponding to the first item of the pattern is significantly greater than a ratio of a value corresponding to the second item of the pattern to the total number of data, the pattern is extracted as an abnormal pattern. When the number of items is three and a pattern with a small number of items has an abnormality, if a ratio of a value corresponding to the pattern to a value corresponding to both the first item and the second item of the pattern is significantly greater than a ratio of a value corresponding to both the second item and the third item of the pattern to a value corresponding to the second item of the pattern and a ratio of a value corresponding to the pattern to a value corresponding to both the first item and the second item of the pattern is significantly greater than a ratio of a value corresponding to both the first item and the third item of the pattern to a value corresponding to the first items of the pattern, the pattern is extracted as an abnormal pattern. |
