OK well if there are several people interested in using this info -- and there are viable algorithms making good use of it, sounds worth integrating. It's not some arbitrary datum -- timestamp is pretty fundamental.
I think this change is basically a change to DataModel. Something like getPreferenceTime(long userID, long itemID) ? What kind of API is needed beyond this? Sean 2010/6/25 Christoph Hermann <[email protected]>: > Am Freitag, 25. Juni 2010 00:43:50 schrieb Tamas Jambor: > > Hello, > >> >> Just wondering if there is an option to store time in one of the >> >> DataModels? Looking at the code, it looks this is not implemented >> >> yet. > >> > No, this is not really part of collaborative filtering per se. But >> > nothing about the model precludes you from storing and using time >> > -- it's just not relevant to the core CF algorithm. For example >> > you're welcome to have a timestamp column in your database table >> > alongside other columns, doesn't matter. > >> thanks. I don't really agree that it's not relevant, though. Many new >> methods are beginning to integrate temporal dynamics into the models. > > I totally agree on that. > What about changing Mahouts core code to be able to implement this more > easily? > > I thought about having an Interface that could be extended depending > which data you have. Since you (almost) always have Users and Items, > that should be default and then additional interfaces could add either > ratings or timestamps (or both) and then extend the code this way. > Also separating User and Item based recommenders would remove the need > to throw UnsupportedOperationExceptions (just a thought). > > I've implemented a recommender for learning environments which is > completely based on timestamps, I'll present it at the upcoming AACE Ed- > Media in Toronto. > The basic idea is that when users behave the same way over time, you can > use timestamps of items and their relations to create recommendations. > So yes, i think there are settings where timestamps are worth to be > used. > > regards > Christoph Hermann > > -- > Christoph Hermann > Institut für Informatik > Tel: +49 761-203-8171 Fax: +49 761-203-8162 > e-mail: [email protected] >
