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Guide to Recommender Systems

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Why are recommender systems relevant for the economic welfare? This presentation explains the Why based on the economic value for social welfare. Both major types of recommender systems (i.e., Content Filtering and Collaborative Filtering) are explained, its pros and cons. Finally, a hybrid approach of using machine learning and the similiarity of machine learning models is presented and compared to traditional recommender systems.

Published in: Data & Analytics
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Guide to Recommender Systems

  1. 1. Guide to Recommender Systems
  2. 2. Who am I Dr. sc. Amancio Bouza Intrapreneur, Recommender System Expert Let’s connect: https://ch.linkedin.com/in/amanciobouza Follow me: https://twitter.com/AmancioBouza
  3. 3. 3 1 Mio $ What are
  4. 4. 4 1 Mio $Prize for beating Netflix’s Recommender System by 10% https://en.wikipedia.org/wiki/Netflix_Prize
  5. 5. 5 Why?
  6. 6. World has changed: Online Retailer vs B&M Retailer 6 Amazon: 2.3 Mio* B&M: 40k-100k* [Brynjolfsson et al., 2003]; *number of books
  7. 7. for US book market in Year 2000 only… imagine today! 7 $1.03B in Social Welfare [Brynjolfsson &. Smith, 2000]
  8. 8. 8 What does it mean?
  9. 9. 9 [Brynjolfsson &. Smith, 2000] Unlimited Online Product Catalogues and Filtering Algorithms have 7-10xHigher Impact on Social Welfare than Price Competition in Competitive Markets
  10. 10. 10 Search Engine: Consumer searches right Product Recommender System: Product finds right Consumer Paradigm Shift
  11. 11. 11 What are Preferences?
  12. 12. 12
  13. 13. Preferences can be described with the Utility Function (Microeconomics) 13
  14. 14. 14 Content Filtering
  15. 15. Use Machine Learning to Learn an Individual’s Preferences 15 [Bouza et al., 2009], [Bouza, 2012]
  16. 16. 16 -> Good -> Bad
  17. 17. Represent Preferences, e.g., as Decision Tree 17 [Bouza, 2012]
  18. 18. Let’s be pragmatic: Machine Learning Model approximates Utility Function 18 [Bouza, 2012]
  19. 19. 19 “Let’s rate an iPod Nano (green) on Amazon and check our recommendations”, 2008
  20. 20. 20 Well… Do you call this a usefull recommendation? Based on a personal true story in 2008
  21. 21. 21 Collaborative Filtering
  22. 22. Basis for Collaborative Filtering: User-Item Matrix 22
  23. 23. 23 Collaborative Filtering: People who shared similar preferences in the past, will share similar preferences in the future
  24. 24. Collaborative Filtering 24
  25. 25. People who share similar prefernces in the past continue to do so in the future. 25 My favourites: “BLACKOUT” and “ZERO” from M. Elsberg
  26. 26. People who have similar preferences in the past, continue to do so in the future. 26 My favourites: “BLACKOUT” and “ZERO” from M. Elsberg What about “HELIX”?
  27. 27. 27 But…
  28. 28. 28 What about both Individuals’ Preferences beside Items both rated? Only Items both rated provides information ? ? ? ? ? ? ? ?
  29. 29. 29 Hypothesis-Based Collaborative Filtering [Bouza, 2008-2012]
  30. 30. Similarity of Hypothesized Preferences aka Machine Learning Models 30 [Bouza, 2009]
  31. 31. 31 Daily Challenges in Data Preparation What’s the movie title in China?
  32. 32. 32 Translated Movie Title: He’s a Ghost http://thoughtcatalog.com/nico-lang/2013/09/51-hilariously-bad-translations-of-movie-titles-that-are-better-than-the-original/
  33. 33. 33 Don‘t worry, no spoiler ;)
  34. 34. Hypothesized Partial Preferences (HPP) 34
  35. 35. 35
  36. 36. Hypothesized Partial Preferences Similarity Matrix 36 [Bouza, 2012]
  37. 37. Similarity of two Machine Learning Models 37 [Bouza, 2012]
  38. 38. Hypothesis-Based Collaborative Filtering outperforms others 38 [Bouza, 2012]
  39. 39. 39
  40. 40. 40 Other Applications of Machine Learning Model Similarity
  41. 41. Applying Hypothesis-Based Collaborative Filtering to Cross-Project Defect Prediction 41[Zenger & Bouza, 2011] http://www.merlin.uzh.ch/publication/show/4535
  42. 42. Building a Texas Hold’em Poker Bot based on a Hypothesis-Based Collaborative Filtering Approach 42[Kaul & Bouza, 2011] http://www.merlin.uzh.ch/publication/show/2488
  43. 43. Group Recommendations in Google Wave Conversion via Chat Bot and Recommender API 43[Bouza, 2009] http://blog.cpoet.net/providing-movie-recommendations-to-groups-in-google-wave/
  44. 44. Your turn! Where are you going to apply this magic formula? 44
  45. 45. Get it Free Download: https://www.linkedin.com/pulse/how-ais-collaborate-retrieve- recommendations-everybody-amancio-bouza?trk=pulse_spock- articles Buy Book on Amazon: 110$ https://www.amazon.com/dp/1105585085 45
  46. 46. More Recommendation Applications: http://blog.cpoet.net/ Find more application and ideas that master and bachelor students implemented here: http://blog.cpoet.net/what-makes-a-location-really-interesting-and-how-to-exploit-it-to-improve-location-recommendations/ http://blog.cpoet.net/applying-collaborative-filtering-to-cross-project-defect-prediction/ http://blog.cpoet.net/building-an-agent-for-texas-holdem-poker-based-on-a-recommender-system/ http://blog.cpoet.net/how-ratings-and-trust-inferrencing-establish-healthyow-ratings-and-trust-inferencing-establish-h-online- markets/ http://blog.cpoet.net/considering-seasonal-effects-in-location-recommendations-with-recommendation-clouds-metaphor/ http://blog.cpoet.net/proposal-using-collaborative-filtering-to-create-a-win-win-win-situation-and-engage-people-with-ubs- has-been-awarded/ http://blog.cpoet.net/applicability-of-social-network-graph-patterns-to-recommender-systems/ http://blog.cpoet.net/providing-movie-recommendations-to-groups-in-google-wave/ http://blog.cpoet.net/personal-private-movie-recommender-system-at-the-semantic-web-challenge/ http://blog.cpoet.net/202/ http://blog.cpoet.net/personal-cross-site-movie-recommender-system-implemented-as-mozilla-firefox-add-on/ http://blog.cpoet.net/probabilistic-partial-user-model-similarity-for-collaborative-filtering/ http://blog.cpoet.net/semtree-ontology-based-decision-tree-algorithm-for-recommender-systems-at-the-iswc-2008/ 46
  47. 47. Let’s connect and exchange ideas Dr. sc. Amancio Bouza Recommender System Expert, Intrapreneur Let’s connect: https://ch.linkedin.com/in/amanciobouza Follow me: https://twitter.com/AmancioBouza

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