"Once we scale up, algorithms must be sensitive to tiny changes in identities and at the same timeinvariant to lighting, pose, age," Kemelmacher-Shlizerman said.
Although the JSR168 API only guarantees that the namespace is unique for one single page, WebSphere Portal makes sure that the namespace is also invariant over time.
Be sure that this id doesn't change over time by inadvertently passing in variables from the controller - in the case of the feed id, you want it to be both unique and invariant.