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|ChenzwBot (Talk · Contribs)|
ChenzwBot patrols the sea of recent changes.
|Flagged?||Yes (11 April 2008)|
|Edit rate:||Variable (Anti-vandalism)|
|Automatic or manual?||Automatic|
|Programming language/s:||PHP and Python|
|Source code published?||https://gitlab.com/antivandalbot-ng (partial)|
- Since 2010: Anti-vandalism task begins, using Chris G Bot's code. Vandalism detection was achieved by evaluating edits using regular expressions. Prone to low detection and high false positive rates.
- Approximately Dec 2015: Bot begins using the revscoring library (which powers ORES) to extract features (e.g. numbers of characters added/removed) about each edit. Vandalism probability is predicted by a Random forest classifier.
- Mid-2016: Bot core rewritten in line with the reactor design pattern.
- 7 May 2018: Bot core rewritten (again) in Python, which is vastly more efficient than the original PHP implementation. Classifier changed to XGBoost.
- Mid-October 2019: Classifier changed to LightGBM, with substantial improvements to how each diff is evaluated. Words added by editors are transformed to tf–idf vectors, and fed into a separate Bayesian classifier. These words are also tagged as nouns/verbs/pronouns etc., with the counts of the various categories becoming new inputs for the main LightGBM classifier.
Summary of algorithm
- Write-up in progress.
- The bot will not revert local sysops and rollbackers.
- The bot will not revert any registered user with more than a certain number of edits.
- The bot will not revert any edit made to a page on the exclusion list. This currently includes Wikipedia:Sandbox, Wikipedia:Introduction, and Wikipedia:Student tutorial.
The bot will not revert to itself if it last reverted the page less than 24 hours ago.Exceptions to this rule include Wikipedia, Simple English Wikipedia, WP:AN, and WP:ST.
- As of 16 December 2019 the bot will instead not revert the same user/page combination more than once every 24 hours. This means that the bot may revert the same page multiple times within a 24 hour window if the vandals are different.
- Due to issues with false positives, the bot will no longer revert any edit outside of article space.