recsys 2015: exploiting regression trees as user models for intent-aware multi-attribute diversity
TRANSCRIPT
RecSys 2015 – 2nd Workshop on New Trends in Content-Based Recommender SystemsSeptember 16 - 20, 2015 in Vienna, Austria
Exploiting Regression Trees as User Models forIntent-Aware Multi-attribute Diversity
Paolo Tomeo, Tommaso Di Noia, Marco de Gemmis, Pasquale Lops, Giovanni Semeraro, Eugenio Di Sciascio
{paolo.tomeo, tommaso.dinoia, eugenio.disciascio}@poliba.it {marco.degemmis, pasquale.lops, giovanni.semeraro}@uniba.it
Polytechnic University of Bari - Bari (ITALY) University of Bari Aldo Moro - Bari (ITALY)
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
Introduction
ProblemHow to diversify with different items attributes
complying with the users interests?
ProposalRegression trees to represent user interests as a combination of characteristics
Evaluation in terms of individual and aggregate diversity
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
Individual Diversity
Same Artist – Low Diversity Diverse Artists
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
Diversity and Satisfaction
Recommendations quality requires diversity even at the cost of reducing accuracy [Ziegler at al. WWW ‘05, McNee et al. CHI ‘06, Zhou at al. PNAS ‘10, Adamopoulos and Tuzhilin RecSys ‘11, Hurley and Zhang TOIT ‘11, Vargas at al. RecSys ‘14, …]
Diversity has a significant positive influence on the user satisfaction (study with 500+ users of Movielens) [Ekstrand et al. “User Perception of Differences in Recommender Algorithms”, RecSys ‘14]
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
How to Diversify
Data
Top-M List
Re-Ranked Top-N List
Recommender System
DiversificationAlgorithm
Items description
User profile
M >> N
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
Diversification Algorithms
Several algorithms presented so far: - MMR (Carbonell and J. Goldstein, SIGIR ‘98)
- IA-Select (Agrawal et al., WSDM ‘09)
- xQuAD (Santos et. al, WWW ’10)- …- BinomDiv (Vargas et. al RecSys ‘14)
Need of information about items- content- external information- statistical information- …
Should take user interests into consideration (intent-aware)- user model
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
Greedy strategy
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
xQuAD
eXplicit Query Aspect Diversification
likelihood of item i being chosen given the feature f
the user u interest in the feature f
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
xQuAD
eXplicit Query Aspect Diversification
Penalization of redundancy
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
Multi-Attribute Diversity
Attribute FeaturesDirector Cameron CroweYear of release 2001Actor Tom Cruise, Cameron Diaz,
Penélope Cruz
Genre Fantasy, Mystery, Romance
Attribute FeaturesDirector Cameron CroweYear of release 1996Actor Tom Cruise, Cuba Gooding Jr.,
Renée Zellweger
Genre Comedy, Drama, Romance
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
Regression Trees as User Models
A regression tree allows to represent user tastes as acombination of interrelated characteristics
Romance Movie
falsetrue
AlPacino acts in
falsetrue
Direct by Crowe
falsetrue
interest = 5 interest = 5 interest = 3Year < 2000
falsetrue
interest = 5 interest = 2.3
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
Rules from Regression Trees
M5Rules produces rules from regression trees.
Good compromise between rules accuracy and compactness
http://weka.sourceforge.net/doc.dev/weka/classifiers/rules/M5Rules.html
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
Rules in Diversification
Data
Recommender System
DiversificationAlgorithm
Items description
User profile
Rule1
Rule2
.
.
.Rulen
Rule1 , Rule3
Rule1
Rule1
Rule1 , Rule3
Rule1 , Rule2
Rule1
Rule5 , Rule6
Rule2
Rule3 , Rule4 Rule5 Rule2 , Rule3 Rule1 , Rule7 Rule1
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
xQuAD adapted for multi-attribute
Original
Multi-attribute
domain of attribute A
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
xQuAD adapted for Rules
Original
For rules
rules of user u matched by item i importance of rule
m for user uimportance of the rule m for item i
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
xQuAD adapted for Rules
Original
For rules
RT binary function
DivRT avg similarity between m and each rule covered by item j
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
Evaluation
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
Datasets
Mappingshttp://sisinflab.poliba.it/semanticweb/lod/recsys/datasets/
• Movielens 1M mapped with Dbpedia-attributes: Genre, Decade of Release, Actors, Directors
- 998,963 ratings from 6,040 users on 3,625 movies- sparsity 95.7%- split 60-40%
• LibraryThing mapped with Freebase-attributes: Genre, Author, Subject
- 565,310 ratings from 7,278 users on 27,358 books- sparsity 99.7%- split 80-20%
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
Evaluation Metrics
Accuracy Precision RecallnDCG
Individual Diversity Intra-List Diversity (ILD)redundancy-aware nDCG (α-nDCG)
Aggregate Diversity Catalog coverage Entropy
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
Evaluation Setting
Two steps
1. Top-200 recommendations computed with BPRMF (MyMediaLite)
2. Top-10 diverse recommendations • repeated varying the value of λ from 0 to 0.95 (step 0.05)
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
Compared Algorithms
Baseline- xQuAD for multi-attribute
Proposed- RT: xQuAD for Rules- DivRT: xQuAD for Rules with a diversity analysis between rules
Combination- xQuAD-after-RT: xQuAD on top-50 from RT- RT-after-xQuAD: RT on top-50 from xQuAD
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
Individual diversityMovielens LibraryThing
ILD
α-nDCG
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
Aggregate diversityMovielens LibraryThing
Coverage
Entropy
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
Outcome
Rule-based approach - less individual diversity + better aggregate diversity
Combination of baseline and proposed approach+ good compromise among accuracy, individual and aggregate diversity
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
ConclusionWe proposed a method to leverage regression trees as user model technique for intent-aware multi-attribute diversity problem
We showed that combining attribute-based and rules-based re-rankings obtains the advantages of both
Future work- propose a method for combining attributes and rules within the same formula - evaluation of impact of our approach on recommendation novelty- evaluation with user study
Exploiting Regression Trees as User Models for Intent-Aware Multi-attribute DiversityP. Tomeo, T. Di Noia, M. de Gemmis, P. Lops, G. Semeraro, E. Di Sciascio
Thanks for your attention!
Q & A