This document presents the proposed research of Soude Fazeli for her PhD on developing a trust-based social recommender system for teachers. The research will involve conducting requirement analysis through interviews of teachers, empirically evaluating recommender algorithms on educational datasets, user studies to evaluate satisfaction, and a pilot implementation. The goal is to help teachers find suitable learning resources and peers by addressing data sparsity through leveraging social relationships between users.

1. A Trust-based Social Recommender
for Teachers
Soude Fazeli, PhD candidate
Dr. Hendrik Drachsler
Dr. Francis Brouns
Prof. Dr. Peter Sloep
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2. The doctoral study is funded by
• NELLL
(Netherlands Laboratory for Lifelong Learning at the OUNL)
• Open Discovery Space (ODS)
A socially-powered, multilingual
open learning infrastructure
to boost the adaptation of
eLearning Resources in Europe
Run-time: 2011-2015
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3. A social space for teachers
Learning Networks?
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4. page 4

5. Recommender systems?
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6. A proposed recommender system for teachers
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Based on the framework proposed by Manouselis &
Costopoulou (2007)

7. Supported tasks
• Find Novel resources
• (Recker et al, 2003), (Lemire et al, 2005), (Rafaeli et al,
2005), (Tang & McCalla, 2005), (Drachsler et al, 2009)
• Find peers
• (Beham et al, 2010), (Recker et al, 2003)
• For more examples, please refer to
• Manouselis N., Drachsler H., Verbert K., Duval E. (2012).
Recommender Systems for Learning book, Springer.
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8. User model
• History-based models and user-item ratings matrix
• Ontology
• TEL variables: knowledge level, interests, goals and tasks, and
background knowledge
• Capturing social data with help of a standard specification:
• FOAF
• CAM
• Annotation scheme (In the context of Organic.Edunet)
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9. A proposed recommender system for teachers
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Based on the framework proposed by Manouselis &
Costopoulou (2007)

10. Similarity
Sparsity!
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11. (Golbeck, 2009; Kamvar et al., 2003; Ziegler & Golbeck, 2007;
Massa & Avesani, 2004; Lathia et al., 2008; Fazeli et al., 2010)
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12. Trust in recommender systems
• Trustworthy users == like-minded users
• Assuming that trust is transitive
• (if A trusts B and B trusts C, then A trusts C)
• Inter-user trust phenomena helps us to infer a relationship
between users
Alice Bob
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13. A social recommender system:
T-index approach
(Fazeli et al., 2010)
• Creates trust relationships between users
• Based on the ratings information
• Proposes T-index concept
• To measure trustworthiness of users
• To improve the process of finding the nearest neighbours
• Inspired on the H-index
• Used to evaluate the publications of an author
• Based on results, T-index improves structure of trust networks of users
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14. Social data
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15. • RQ1: How can the sparsity problem within
educational datasets be solved by using inter-user
trust relationships which originally come from the
social data of users?
• RQ2: How can teachers’ networks be made to
evolve by the use of social data?
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16. Proposed research
1. Requirement analysis
• Literature review
• Interview study
2. Dataset-driven study
3. User evaluation study
4. Pilot study
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17. 1. Requirement analysis
• Goal
• Investigating the teachers’ main needs and requirements
• Method
• Nominal group technique (NGT)
• 18 teachers (novices, experts, mentors and supervising teachers) from the
Limburg area, the Netherlands
• Inviting teachers to cluster the generated ideas by WebSort
• Survey on use of social media by teachers
• Description
• “What kind of support do you need to provide innovative teaching at your
school?"
• Writing down the ideas, discussion, clustering, ranking the ideas
• Expected outcomes
• An inventory list of teachers’ needs and requirements
• A framework to identify suitable recommender systems’ strategies for our
page 17 target users

18. Proposed research
1. Requirement analysis
• Literature review
• Interview study
2. Dataset-driven study
3. User evaluation study
4. Pilot study
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19. 2. Dataset study
• Goal
• To find out the most suitable recommender system algorithm for teachers
• Method
• An offline empirical study of candidate algorithms (T-index, Pearson, Slope-
one, Tanimoto)
• TravelWell, Organic.Edunet, eTwinning (TELeurope, Mace, Openscout)
• Variables to be measured
• Prediction accuracy, coverage, and F1
• Expected outcomes
• If the T-index approach can help to deal with the sparse data in the used
datasets
• Which of the recommender system algorithms suits teachers best
(Verbert et al., 2011)
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20. Proposed research
1. Requirement analysis
• Literature review
• Interview study
2. Dataset-driven study
3. User evaluation study
4. Pilot study
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21. 3. User evaluation study
• Goal
• To study users’ satisfaction
• Method
• Questionnaire
• Pre and post test of knowledge gain
• Variables to be measured
• Interestingness and value-addedness (Tang & McCalla, 2009)
• Prediction accuracy, coverage, and F1 measures
• Expected outcomes
• Initial feedback by end-users on users’ satisfaction as an input for pilot study
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22. Proposed research
1. Requirement analysis
• Literature review
• Interview study
2. Dataset-driven study
3. User evaluation study
4. Pilot study
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23. 4. Pilot study
• Goal
• To deploy the final release
• To test it under realistic operational conditions with the end-users
• Method
• Evaluating performance of the designed recommender system algorithm
• Study the structure of the teachers’ networks
• Variables to be measured
• Prediction accuracy and coverage
• Effectiveness in terms of total number of visited, bookmarked, or rated
learning objects for two groups of users
• Indegree distribution to study how the structure of teachers’ networks changes
• Expected outcomes
• Empirical data on prediction accuracy and coverage
• The visualization of teachers’ networks
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24. Conclusion
• The aim is to support teachers to find the most
suitable content or people
• Recommender systems as a solution
• How to overcome the sparsity problem by use of
social data
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25. Ongoing and Further work
• Requirement analysis
• Data collection (done)
• Teachers from the Netherlands
• European teachers in an Open Discovery Space Summer School, Greece
• Publishing the results as an extensive requirement analysis for teachers all
over the Europe (in progress)
• Data set study
• Testing data sets with users’ ratings (successfully done)
• Testing data sets based on implicit users’ feedback (tags, bookmarks,
comments, blogs, etc) (in progress)
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26. Soude Fazeli
PhD candidate
Open University of the Netherlands
Centre for Learning Sciences and Technologies
(CELSTEC) PO-Box 2960
6401 DL Heerlen, The Netherlands
email: soude.fazeli@ou.nl
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