1. Improvement of user-based CF
by using spectral clustering techniques
ACM Conference on Recommender Systems 2012 – Poster slam
September 11, Dublin, Ireland

2. Context: cluster-based CF
neighbours identified based on a clustering method
Spectral Clustering: Normalised Cut
ACM Conference on Recommender Systems 2012 – Poster slam
September 11, Dublin, Ireland

3. Context: cluster-based CF
neighbours identified based on a clustering method
Spectral Clustering: Normalised Cut
Better than k-Means: performance
k-Means NCut
0.12
0.10
0.08
P
@ 0.06
5
0.04
0.02
0.00
50 100 150 200 250 300 350 400 450 500 550 600
k
ACM Conference on Recommender Systems 2012 – Poster slam
September 11, Dublin, Ireland

4. Context: cluster-based CF
neighbours identified based on a clustering method
Spectral Clustering: Normalised Cut
Better than k-Means: coverage
cov(k-Means) cov(Ncut)
100
90
C 80
o
70
v
60
e
50
r
a 40
g 30
e 20
10
0
50 100 150 200 250 300 350 400 450 500 550 600
k
ACM Conference on Recommender Systems 2012 – Poster slam
September 11, Dublin, Ireland

5. Context: cluster-based CF
neighbours identified based on a clustering method
Spectral Clustering: Normalised Cut
Better than k-Means
Also better than MF and standard UB
UB50 MF NCut
0.12
0.10
0.08
P
@ 0.06
5
0.04
0.02
0.00
50 100 150 200 250 300 350 400 450 500 550 600
k
ACM Conference on Recommender Systems 2012 – Poster slam
September 11, Dublin, Ireland

6. Using Graph Partitioning Techniques
for Neighbour Selection in
User-Based Collaborative Filtering
Alejandro Bellogín Javier Parapar
Information Retrieval Group Information Retrieval Lab
Universidad Autónoma de Madrid University of A Coruña
ACM Conference on Recommender Systems 2012 – Poster slam
September 11, Dublin, Ireland