FCE Seminar -

Machine Learning

Paper:

Automated Product Recommendations Without Observable Features: An Initial Investigation'd3

Mary S. Lee and Andrew W. Moore

Question (in academic sense): Can you accurately predict how a consumer will rate a product based historical information? Can you learn about the tastes of given consumer?


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Question (in practical sense): Can you tell me whether I should bother watching this weeks Star Trek episode?


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How do you decide whether you want to watch a given episode of Star Trek?

My answers:

Contribution of paper: They attempt to model these three methods into three separate algorithms and then test these algorithms on synthesized data and real data that is both sparse and dense.


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They compare them to the two simple popularity contests.

Model for their Algorithms:


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consumers

Linfeat Algorithm

Direct approach to prediction by finding the best fit for the two matrices, one of all features and one of all preferences.


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Assumes a direct relationship between consumer preferences and product features.

Nearest neighbor Algorithm


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Indirect approach(inferring). Look for a consumer that has had similar ratings to yours on previous products and uses their rating of current product.

Regression-based Algorithm

Indirect approach(inferring). Look for a strong correlation between your previous ratings and ratings of others.

Traditional Popularity Algorithms:

prodav (NY Times best seller)


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globalav (watch 'd4em all)


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Results


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Star Trek Episodes: dense data = 88.8% of maximum entries in polling database of 1055 votes from 36 people on 33 episodes.

Best to worse: (mean error)

Pt: regression offers a 15% improvement over prodval.

Movies: sparse data = 23% of maximum entries in polling database of 4109 ratings from 141 people

and 94 movies.

Best to worse: (mean error)

Pt: Regression offer a 10% improvement over prodval.

Conclusions

These algorithms are better at predicting your rating on a particular movie than they are at predicting your taste.


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Linfeat, nearest neighbor and regression all perform similarly, but linfeat is much faster.

Increasing density of data will increase utility of algorithms by up to 20% over prodval.

Possible Extensions

Use explicit product features (ie. genre of movie)

Use explicit consumer features (ie. gender)

Collect and interpret data from regrets (learn from your mistakes) ??


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Additional annotations.