As mentioned in Section 
,
the profile cannot be modified in response to user feedback without the document
representation. At this stage in the Information Processing module, the document
representation is now available and the profile can be modified. In fact, the
profile must incorporate the changes due to user feedback before newer documents
can be scored since the feedback predates the current round of document scoring.
The profile maintains a list of articles for which feedback was received,
if any, and the amount of feedback for each, during the last user session. This
can be seen in the items listed under ``ArtFeedback'' in table .
Once the field vectors for a feedback article are available, the profile is
modified as described in Section .
An implementation related issue is that the size of the term vector (especially keywords), could potentially grow infinitely long as new terms are introduced into the profile through feedback. The size of can be controlled by either having an upper limit on the number of terms to be retained, or by having a threshold for the ratio of the lowest term weight to the highest.