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From ameh <>
Subject Combining CF and Content-based recommendations
Date Thu, 05 Apr 2012 20:20:58 GMT

I'm a new user to Mahout and am currently using the 1m ratings MovieLens
data file. I had a couple of questions: 

#1. /ItemBased using CF and content-based/
I've been thinking of a way to incorporate content-based recommendations
(using additional attributes of an item, in this case a movie) by utilizing
a utility matrix where the rows correspond to users and columns correspond
to movies. The individual entries (say entry(i,j)) are the preferences
(ratings) expressed by user i for movie j. I know you can include additional
columns, say genre, and identify a value for that entry based on the movies
rated by a particular within that genre type. 

This matrix would be pretty sparse. But I'm not sure *how* to combine this
with the out-of-box recommendations provided in Mahout. How will I do this
if my data model (a matrix) is different from DataModel?

#2. /Adding in demographic information/
I'd like to recommend movies to users, and not users to users, so I'm not
sure how I can incorporate user "attributes" (e.g. their age group,
occupation, etc) without doing this. The Libimseti dating recommendation
makes sense - there, we're recommending users to users. In my case, does it
make sense to just filter based on a particular e.g. age group, and make a
recommendation based on this filtered group? (I guess this rests on the
assumption that my filter will return users that are more similar to each
other because they are in the same demographic category (in this case age
group).) Or is there a better method of doing this?

Any insight or advice based on past experience with this would be very
helpful. Thanks in advance.

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