interactive recommender systems

Interactive Recommender Systems:Bridging the gap between predictive

algorithms and interactive user interfaces

Denis Parra, Ph.D. Information SciencesAssistant Professor, CS DepartmentSchool of EngineeringPontificia Universidad Católica de Chile

UFMG, March 29th 2017

Outline

• Brief Personal Introduction• Computer Science at PUC Chile• Projects at SocVis Lab

• Overview of Recommender Systems • Interactive Recommender Systems

• Summary & Current & Future Work

March 29th, 2017 D.Parra ~ UFMG – Invited Talk 2

1 slide Geography Class: Chile• One third of the 16 million Chileans lives in Santiago,

the Capital• But Chile is a looong country (4.000 Km), in the north

is hot and dry, in the south (Patagonia) is very cold.Very Hot!

Very Cold!

My hometown!Valdivia

Santiago, PUC Chile

Personal Introduction 1/3

• B.Eng. and Engineering in Informatics from Universidad Austral de Chile (2004), Valdivia, Chile

• Ph.D. in Information Sciences at University of Pittsburgh (2008-2013), Pittsburgh, PA, USA

• In 2009 I did an internship at Trinity College Dublin, with researcher Alexander Troussov (IBM)

• In 2010 I did another internship at Telefonica I+D, Barcelona, with Xavier Amatrian (now VP Quora)

• 2013: Moved back to Santiago, Chile • Department of CS, School of Engineering, PUC.

DCC, Engineering, PUC Chile• DCC: Departamento de Ciencia de la Computación• Programs: BEng, Engineering title, Master, PhD• Research Areas:

– Databases and Semantic Web– Information Technologies– Machine Learning and Computer Vision (GRIMA)– Software Engineering– Educational Technologies, MOOCs

http://dcc.ing.puc.cl

Academic activities (2017)

• Research topics: Recommender Systems/Personalization, Visualization, SNA.

• Teaching: Data Mining, Recommender Systems, Information Visualization, SNA.

• Leading the Social Computing and Visualization (SocVis) Lab.

SocVis Lab

http://www.socvis.clMarch 29th, 2017 D.Parra ~ UFMG – Invited Talk 9

People, Publications, News (ND)

Projects at SocVis

• Mood-based music artists recommendation– Collaboration with J. O’Donovan (UCSB)– Student: Raimundo Herrera

• IR on evidence-based Medicine– Help doctors on answering clinical questions– Student: I. Donoso, collaboration Epistemonikos

• Artwork Recommendation – Collaboration with online artwork store UGallery– Students: P. Messina & V. Dominguez

Recommender Systems Class

• Recommender Systems at PUC Chilehttp://web.ing.puc.cl/~dparra/classes/recsys-2016-2/

INTRODUCTION TO RECSYSRecommender Systems

* Danboard (Danbo): Amazon’s cardboard robot, in these slides it represents a recommender system

Recommender Systems (RecSys)Systems that help (groups of) people to find relevant items in

a crowded item or information space (MacNee et al. 2006)

Why do we care about RecSys?

• RecSys have gained popularity due to several domains & applications that require people to make decisions among a large set of items.

A lil’ bit of History

• First recommender systems were built at the beginning of 90’s (Tapestry, GroupLens, Ringo)

• Online contests, such as the Netflix prize, grew the attention on recommender systems beyond Computer Science(2006-2009)

The Recommendation Problem

• The most popular way of presenting the recommendation problem is rating prediction:

• How good is my prediction?

Item 1 Item 2 … Item m

User 1 1 5 4

User 2 5 1 ?

User n 2 5 ?

Predict!

Recommendation Methods

• Without covering all possible methods, the two most typical classifications on recommender algorithms are

Classification 1 Classification 2- Collaborative Filtering- Content-based Filtering- Hybrid

- Memory-based- Model-based

Collaborative Filtering (User-based KNN)• Step 1: Finding Similar Users (Pearson Corr.)

Active user

User_1

User_2

User_3

active user

user_1

user_2

user_3

Collaborative Filtering (User-based KNN)• Step 1: Finding Similar Users (Pearson Corr.)

Active user

User_1

User_2

User_3

∑∑∑

⊂⊂

−−

−−=

CRi nniCRi uui

CRi nniuui

rrrrnuSim

22 )()(

))((),(

active user

user_1 0.4472136

user_2 0.49236596

user_3 -0.91520863

Collaborative Filtering (User-based KNN)

• Step 2: Ranking the items to recommend

Active user

User_1

User_2

Item 1

Item 2

Collaborative Filtering (User-based KNN)

• Step 2: Ranking the items to recommend

Active user

User_1

User_2

∑∑

⊂−⋅

)(),(),(

uneighborsn

uneighborsn nni

u nuuserSim

rrnuuserSimriupred2

Item 1

Item 2

Item 3

Pros/Cons of CFPROS:• Very simple to implement• Content-agnostic• Compared to other techniques such as content-

based, is more accurate. There is also the Item KNN.CONS:• Sparsity• Cold-start• New Item

Content-Based Filtering• Can be traced back to techniques from IR, where

the User Profile represents a query.

user_profile = {w_1, w_2, …., w_3} using TF-IDF, weighting

Doc_1 = {w_1, w_2, …., w_3}

Doc_2 = {w_1, w_2, …., w_3}

Doc_3 = {w_1, w_2, …., w_3}

Doc_n = {w_1, w_2, …., w_3}

PROS/CONS of Content-Based FilteringPROS:• New items can be matched without previous

feedback• It can exploit also techniques such as LSA or LDA• It can use semantic data (ConceptNet, WordNet,

etc.)CONS:• Less accurate than collaborative filtering• Tends to overspecialization

Hybridization• Combine previous methods to overcome their

weaknesses (Burke, 2002)

C2. Model/Memory Classification

• Memory-based methods use the whole dataset in training and prediction. User and Item-based CF are examples.

• Model-based methods build a model during training and only use this model during prediction. This makes prediction performance way faster and scalable

Model-based: Matrix Factorization

Latent vector of the itemLatent vector of the user

SVD ~Singular Value Decomposition

PROS/CONS of MF and latent factors model

PROS:• So far, state-of-the-art in terms of accuracy (these

methods won the Netflix Prize)• Performance-wise, the best option nowadays: slow

at training time O((m+n)3) compared to correlation O(m2n), but linear at prediction time O(m+n)

CONS:• Recommendations are obscure: How to explain that

certain “latent factors” produced the recommendation?

Other paradigms and techniques

• Recommendation as a graph problem: – Model the problem as diffusion or link prediction– Personalized PageRank (Kamvar et al, 2010), (Santos et

al 2016)• Recommendation as a ranking problem:

– Rather than predicting ratings, predict a Top-N list– Learning-to-rank approaches developed in the IR

community– Karatzoglou et al. (2013), Shi et al. (2014), Macedo et al.

(2015)

(Important) RecSys Topics Not Covered in this Presentation

• Learning to rank• Graph-based methods• Context-aware recommenders• Recommendation problem as next-item in sequence• User-centric evaluation frameworks• Multiarmed Bandits• Reinforcement Learning• ... You need to take Professor Santos’ course J

Rethinking the Recommendation Problem

• User feedback is scarce: need for exploiting different sources of user preference and context

• Ratings are scarce: need for exploiting other sources of user preference

• User-centric recommendation takes the problem beyond ratings and ranked lists: evaluate user engagement and satisfaction, not only RMSE/MAP

• Ratings are scarce: need for exploiting other sources of user preference

• User-centric recommendation takes the problem beyond ratings and ranked lists: evaluate user engagement and satisfaction, not only RMSE/MAP

• Several other dimensions to consider in the evaluation: novelty of the results, diversity, coverage (user and catalog), trust

• Study de effect of interface characteristics: controllability, transparency, explainability.

My Take on RecSys Research (2009 ~)

My Work on RecSys

• In my research I have contributed to RecSys by:– Utilizing other sources of user preference (Social Tags)– Exploiting implicit feedback for recommendation and for

mapping explicit feedback– Studying interactive interfaces: the effect of visualizations and

user interaction on user satisfaction, perception of trust and accuracy.

• Nowadays: Focus on interactive exploratory interfaces for recommender systems

This is not only My work J• Dr. Peter Brusilovsky

University of Pittsburgh, PA, USA

• Dr. Alexander TroussovIBM Dublin and TCD, Ireland

• Dr. Xavier AmatriainTID / Netflix /Quora

• Dr. Christoff TrattnerNTNU, Norway

• Dr. Katrien VerbertKU Leuven, Belgium

• Dr. Leandro Balby-MarinhoUFCG, Brasil

VISUALIZATION + USER CONTROLLABILITY

Part of this work with Katrien Verbert

Human Factors in RecSys• Transparency and Explainability: Konstan et al (2000),

Tintarev and Mastoff (2010)

• Frameworks to evaluate RecSys user studies: ResQue (Pu et al , 2010), Knijnenburg et al (2012)

• Controllability and Inspectability: O’Donovan (2008), Knijnenburg et al (2010, 2012), Hijikata (2012), Ekstrand et al (2015)

• Visualization and Interfaces: O’Donovan (2008 - ..), Verbert et al (2013), Parra et al (2014), Loepp et al (2014, 2017),

Visualization & User Controllability

• Motivation: Can user controllability and explainability improve user engagement and satisfaction with a recommender system?

• Specific research question: How intersections of contexts of relevance (of recommendation algorithms) might be better represented for user experience with the recommender?

Traditional RecSys InterfaceMovieLens: example of traditional recommender list

Explanations and Control

Options of User Control

Explainability

Recommendations of books

GoodReads: Book recommender system

PeerChooser (2008) Controllability in CF

O’Donovan et al. “PeerChooser: Visual Interactive Recommendation” (2008)

SmallWorlds: Expanded Explainability

Gretarsson et al. “SmallWorlds: Visualizing social recommendations” (2010)

TasteWeights: Hybrid Control and Inspect

Bostandjev et al. “TasteWeights: A Visual Interactive Hybrid Recommender System” (2012)

Controllability: Sliders that let users control the importance of preferences and contexts

Inspectability: lines that connect recommended items with contexts and user preferences

IUI 2017

• Loepp et al. (2017)

More Details? Check our survey

He, C., Parra, D., & Verbert, K. (2016). Interactive recommender systems: a survey of the state of the art and future research challenges and opportunities. Expert Systems with Applications, 56, 9-27.

Visualization & User Controllability• Motivation: Can user controllability and

explainability improve user engagement and satisfaction with a recommender system?

• Specific research question: How overlapping contexts of relevance (of recommendation algorithms) might be better represented for user experience with the recommender?

• Our scenario: Conference articles

Research Platform

• The studies were conducted using Conference Navigator, a Conference Support System

• Our goal was recommending conference talks

Program Proceedings Author List Recommendations

http://halley.exp.sis.pitt.edu/cn3/

TalkExplorer – IUI 2013• Adaptation of Aduna Visualization to CN• Main research question: Does fusion (intersection) of

contexts of relevance improve user experience?

TalkExplorer - I

EntitiesTags, Recommender Agents, Users

TalkExplorer - II

RecommenderRecommender

Cluster with intersection of entities Cluster (of

talks) associated to only one entity

• Canvas Area: Intersections of Different Entities

TalkExplorer - III

ItemsTalks explored by the user

Our Assumptions

• Items which are relevant in more that one aspect could be more valuable to the users

• Displaying multiple aspects of relevance visually is important for the users in the process of item’s exploration

TalkExplorer Studies I & II• Study I

– Controlled Experiment: Users were asked to discover relevant talks by exploring the three types of entities: tags, recommender agents and users.

– Conducted at Hypertext and UMAP 2012 (21 users)– Subjects familiar with Visualizations and Recsys

• Study II– Field Study: Users were left free to explore the interface.– Conducted at LAK 2012 and ECTEL 2013 (18 users) – Subjects familiar with visualizations, but not much with

RecSys

Evaluation: Intersections & Effectiveness

• What do we call an “Intersection”?

• We used #explorations on intersections and their effectiveness, defined as:

Effectiveness =

Results of Studies I & II

• Effectiveness increases with intersections of more entities

• Effectiveness wasn’t affected in the field study (study 2)

• … but exploration distribution was affected

More Details About TalkExplorer• Verbert, K., Parra, D., Brusilovsky, P., & Duval, E. (2013).

Visualizing recommendations to support exploration, transparency and controllability. In Proceedings of the 2013 international conference on Intelligent user interfaces (pp. 351-362). ACM.

• Verbert, K., Parra, D., & Brusilovsky, P. (2016). Agents Vs. Users: Visual Recommendation of Research Talks with Multiple Dimension of Relevance. ACM Transactions on Interactive Intelligent Systems (TiiS), 6(2), 11.

SETFUSION: VENN DIAGRAM FOR USER-CONTROLLABLE INTERFACE

SetFusion – IUI 2014

SetFusion I

Traditional Ranked List

Papers sorted by Relevance. It combines 3 recommendation approaches.

SetFusion - IISlidersAllow the user to control the importance of each data source or recommendation method

Interactive Venn DiagramAllows the user to inspect and to filter papers recommended. Actions available:- Filter item list by clicking on an area- Highlight a paper by mouse-over on a circle- Scroll to paper by clicking on a circle- Indicate bookmarked papers

Study : iConference• A laboratory within-subjects study. 40 subjects.• In Preference elicitation phase, people did not have limit of

papers. Under RecSys interfaces, minimum limit was 15.• In bookmarking, subjects could pick items relevant to a)

themselves, b) themselves and others, and c) only to others.

$12/hourAvg: 1.5 hours

Study : Population and General Stats

Non-controllable Controllable# Total bookmarks 638 625# Average bookmarks/user 15.95 15.63# Average rating 2.48±0.089 2.46±0.076

Gender Female: 17 Male: 23

Age 31.75±6.5Native Speaker Yes: 10 No: 30

Subject Occupation Information Sc. (16), Library Sc.(9), Comp. Sc. (6), Telecomm (3), (+6)

PCA15 questions

on pre-questionnaire

4 Factors (User Characteristics)• Expertise in domain• Engaged with iSchools• Trusting Propensity• Experience w/RecSysDropped• Experience w/CN

Study 2: Results (1)Variables Comment

User Engagement

Significant Talks explored, clicks (nbr. actions) , time spent on task All significantly higher in controllable interface

User Experience

Significant MAP Significantly higher in controllable interface

User Characteristics

Significant Trusting prop.: increases use of Venn diagram and MAPNative speaker: Decreases time spent on taskGender: Being male increases use of sliders Age: Each additional year decreases use of sliders

Trusting propensityconfirms results of previous studies

Rating per method – Effect of Visuals

Gender Differences on SetFusion?

Study : Results (2)Post-session surveys Controllable No-Controllable

Understandability 4.05±0.09*** 2.95±0.16

Satisfaction with interface 4.28±0.09*** 3.4±0.16

Confidence of not missing relevant talks 3.9±0.11*** 3.13±0.15

Intention: I would use it again 4.23±0.09*** 3.45±0.15

Intention: I would recommend system to colleagues 4.28±0.09*** 3.48±0.16

Venn diagram visualization was useful to identify talksrecommended by a specific or by a combination ofrecommendation methods.

4.35±0.11 --

Venn diagram visualization supported explainability4.08±0.13 --

Satisfaction due to ability to control 4.05±0.12 --

Perception of Control with Sliders 4.03±0.13 --

Study : Results (3)Non-control Controllable Both None

Which interface did you prefer? 0 36 4 0Non-control Controllable None Both

Which interface would you suggest to implement permanently in CN?

1 33 1 5

“I like the Venn diagram especially because most papers I was interested in fell in the same intersections, so it was pretty easy to find and bookmark”

“I thought the controllable one adds unnecessary complication if the list is not very long”

“I prefer the sliders (over Venn diagram) because I have used a system before to control search results with a similar widget, so it was more familiar to me.”

Study Takeaways• User Engagement: Controllable interface significantly

drives more user engagement (objective and subjective metrics)

• User Experience: Controllable interface improves user experience by allowing user to interactively control ranking (MAP) and improving explainability.

• User characteristics: Trusting propensity affects positively engagement and experience, engagement with iSchools shows the opposite. Males have a tendency to prefer sliders over Venn diagram to control and filter.

More Details on SetFusion?

• Effect of other variables: gender, age, experience with in the domain, familiarity with the system

• Check our paper in the IJHCS “User-controllable Personalization: A Case Study with SetFusion”: Controlled Laboratory study with SetFusion versus traditional ranked list

Study 2 – UMAP 2013

• Field Study: let users freely explore the interface

- ~50% (50 users) tried the SetFusion recommender

- 28% (14 users) bookmarked at least one paper

- Users explored in average 14.9 talks and bookmarked 7.36 talks in average.

A AB ABC AC B BC C15 7 9 26 18 4 1716% 7% 9% 27% 19% 4% 18%

Distribution of bookmarks per method or combination of methods

Hybrid RecSys: Visualizing Intersections

Clustermap Venn diagram

• Clustermap vs. Venn Diagram

TalkExplorer vs. SetFusion

• Comparing distributions of explorations

In studies 1 and 2 over TalkExplorer we observed an important change in the distribution of explorations.

TalkExplorer vs. SetFusion

• Comparing distributions of explorations

Comparing the field studies:- In TalkExplorer, 84% of

the explorations over intersections were performed over clusters of 1 item

- In SetFusion, was only 52%, compared to 48% (18% + 30%) of multiple intersections, diff. not statistically significant

Summary & Conclusions

• We showed that intersections of several contexts of relevance help to discover relevant items

• The visual paradigm used can have a strong effect on user behavior: we need to keep working on visual representations that promote exploration without increasing the cognitive load over the users

Limitations & Future Work

• Apply our approach to other domains (fusion of data sources or recommendation algorithms)

• For SetFusion, find alternatives to scale the approach to more than 3 sets, potential alternatives:– Clustering and – Radial sets

• Consider other factors that interact with the user satisfaction: – Controllability by itself vs. minimum level of accuracy

Current Work on Interfaces

• MoodPlay– With Ivana Andjelkovic & John O’Donovan (UCSB)

Andjelkovic, I., Parra, D., & O'Donovan, J. (2016, July). Moodplay: Interactive Mood-based Music Discovery and Recommendation. In Proceedings of the 2016 Conference on User Modeling Adaptation and Personalization (pp. 275-279). ACM.

MoodPlay

• https://www.youtube.com/watch?v=eEdo32oOmcE

Emotion Models

• Modelo de emociones de Russel(1980)

• GEMS (2008)

Moods and Music: the GEMS model

System Architecture

Hybrid Recommendation Approach

User Study

• Conducted on Mechanical Turk, 4 conditions

Interactions

Interaction Stats

Diversity Consumption

User Prior Mood and Artist Mood

Post-Study Survey

Accuracy

Post-Study Survey

Diversity

Post-Study Survey

Confusing Interface

Post-Study Survey

Easy to use

CONCLUSIONS (& CURRENT) & FUTURE WORK

Challenges in Interactive RecSys

• Objectives• Controllability• Context-aware recommendations• Privacy• Visualization Techniques• Interaction Techniques• Conversation Interfaces• Evaluation Methodology

Future Work

• Opportunities for using new devices (Sensors on Stmartphones, EEG)

• Although new devices can capture a lot of new types of data, there is still a lot to be done with data we already produce but we haven’t consumed (user logs on social web sites, etc.)

3/29/17 D. Parra, FuturePD talk, UMAP 2016 95

MoodPlay in the Chilean news

Moodplay as therapy?

• S. Koelsch. A neuroscientific perspective on music therapy. Annals of the New York Academy of Sciences, 1169(1):374–384, 2009.

• Music can help on modulate certain mental states.

Previous work: MIT Mood Meter

• http://moodmeter.media.mit.edu/

Input Data: from Social Networks?

• Michelle Zhou’s personality profile

Visual emotion detection

• https://github.com/auduno/clmtrackr

Using EEG (BCI)

EMOTIVhttp://emotiv.com/epoc/

NEUROSKYhttp://neurosky.com/biosensors/

Heatmaps to Moodplay

THANKS!dparra@ing.puc.cl

EpistAid

• Epistemonikos: Evidence-based Medicine• Physicians answer clinical questions

EpistAid 2

• Process of building evidence matrices is really slow

EpistAid: IUI to support physicians

• Study 1: Relevance Feedback to find missing papers faster, off-line evaluation

• Study 2: Study with physicians at PUC

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