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Outline. IntroductionBackgroundItem-based Collaborative FilteringRandom Walk Model for Product RecommendationBasket-Sensitive Random Walk on Bipartite NetworkExperimentsConclusions and Future WorkMy thoughts. Introduction. Shopping websitesforgotten itemsnew but relevant productsBuy novel
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1. Grocery Shopping Recommendations Based on Basket-Sensitive Random Walk KDD 2009
Ming Li, Benjamin Dias, Ian Jarman, Wael El-Deredy, Paulo J. G. Lisboa
2. Outline Introduction
Background
Item-based Collaborative Filtering
Random Walk Model for Product Recommendation
Basket-Sensitive Random Walk on Bipartite Network
Experiments
Conclusions and Future Work
My thoughts
3. Introduction Shopping websites
forgotten items
new but relevant products
Buy novel items less frequently
4. Background Item-based Collaborative Filtering
Random Walk Model for Product Recommendation
5. Item-based Collaborative Filtering vs User-based?
Cosine-based similarity(symmetric)
Conditional probability based similarity(asymmetric)
6. Item-based Collaborative Filtering Cosine-based similarity(symmetric):
R: user-item matrix
R*,i : vector notation of its ith column.
Example:
7. Item-based Collaborative Filtering Conditional probability based similarity(asymmetric):
a ? [0, 1]
Freq(i): number of users that have purchased item i in the training data
R(i, j): (i, j) element in the normalized n × m user-item matrix
Example:
sim(i, j) = 10 / 4 × 3 (a = 1)
8. Random Walk Model for Product Recommendation
Random Walk Model:
P: transition matrix
P(i, j): transition probability from the page j to the page i
Rn: ranking vector of all the pages
d ? (0, 1) is a damping factor
U: unit vector
Movie recommendation
9. Basket-Sensitive Random Walk on Bipartite Network
First-Order Transition Probability:
10. Basket-Sensitive Random Walk on Bipartite Network
First-Order Transition Probability:
Example:
I = 2, j = 1, k=2
11. Basket-Sensitive Random Walk on Bipartite Network
First-Order Transition Probability:
a1, a2 ? [0, 1]
12. Basket-Sensitive Random Walk on Bipartite Network
=dP(I - dP)-1
Rbasket : basket-based scores
Ui basket = 1/m, if the ith product is in the basket
0, otherwise
m: number of products in the current basket
13. Basket-Sensitive Random Walk on Bipartite Network
14. Experiments Binary Hit Rates with Popularity Based Leave-three-Out Protocol
Weighted Hit Rates with Leave-One-Out Protocol
15. Conclusions and Future Work Propose a basket-sensitive random walk model for personalized recommendation in the grocery shopping domain.
Deploy the network-based approach in a live recommender system.
16. My thoughts How to combine it with association rules?