Comment 1 for bug 1492090

For contributors who do not have static profile in Stackalytics the affiliation is calculated based on email. If email belongs to any of corporate domains then it is assumed that contributor affiliated with that company, otherwise it is shown as independent. The algorithm works per every item and preserves history.

In your case the flow was the following (see http://stackalytics.com/report/users/zhang-quanwei):
  * filed bugs do not contain email, so affiliation is meant as "independent"
  * then goes patch https://review.openstack.org/#/c/218731/ which was done from private email, so no changes to affiliation
  * commit on 31 Aug also attributed with private email
  * patch into Nova https://review.openstack.org/#/c/220877/ is done from corporate email, enforcing changes of profile affiliation to Fujitsu.

Further contribution will also be assigned to Fujitsu, to fix the old please send a patch with static profile into Stackalytics' default_data (https://wiki.openstack.org/wiki/Stackalytics#Company_affiliation)