Bias in the Social Web
•Transferir como PPTX, PDF•
2 gostaram•1,060 visualizações
Keynote at LWA 2015, Trier, October 2015
Recomendados
Recomendados
Mais conteúdo relacionado
Semelhante a Bias in the Social Web
Semelhante a Bias in the Social Web (20)
Mais de Steffen Staab
Mais de Steffen Staab (20)
Último
Último (20)
Bias in the Social Web
- 1. Steffen Staab Bias in the Social Web 1Institute for Web Science and Technologies · University of Koblenz-Landau, Germany Web and Internet Science Group · ECS · University of Southampton, UK & Bias in the Social Web Steffen Staab, Christoph Kling & Team University of Southampton & Universität Koblenz-Landau
- 2. Steffen Staab Bias in the Social Web 2 Produce Consume Cognition Emotion Behavior Socialisation Knowledge Observable Micro- interactions in the Web Apps Protocols Data & Information Governance WWW Observable Macro- effects in the Web Web Science
- 3. Steffen Staab Bias in the Social Web 3 Web Observatories Konect
- 4. Steffen Staab Bias in the Social Web 4 Bias in the Data Bias in the Algorithm Bias in the Social Machine WebObservatory
- 5. Steffen Staab Bias in the Social Web 5 Bias in the Data
- 6. Steffen Staab Bias in the Social Web 6 Observing Bias in Data Credit Hire Sex Ethnic Zip Height ... ... + + + - - + + + - - correlated Data protection laws suggest not to process sensitive data attributes like „sex“ or „ethnic“
- 7. Steffen Staab Bias in the Social Web 7
- 8. Steffen Staab Bias in the Social Web 8 Observing Bias in Social Networks (Lerman et al 15)
- 9. Steffen Staab Bias in the Social Web 9 Geographic Bias in the Algorithm
- 10. Steffen Staab Bias in the Social Web 10 fish, rice seafood, fish seafood, shrimp lobster, wine seafood, fish, salmon fish, salmon, wine rice, fish lobster, seafood, shrimp coffee coffee, wine coffee wine wine pizza, wine pizza, wine pasta, wine pasta, shrimp lobster, shrimp seafood, shrimp Tagged photos with geo-coordinates from Flickr
- 11. Steffen Staab Bias in the Social Web 11 fish, rice seafood, fish seafood, shrimp lobster, wine seafood, fish, salmon fish, salmon, wine seafood, shrimp lobster, seafood, shrimp coffee coffee, wine coffee italian, wine wine pizza, wine italian, pizza, wine pasta, wine pasta, shrimp seafood fish lobster shrimp crab wine salmon wine pizza coffee italian pasta seafood, shrimp lobster, shrimp Tasks: Discovering topics, finding clusters
- 12. Steffen Staab Bias in the Social Web 12 Cultural areas, country borders, geographical features and other geographical observations exhibit complex spatial distributions wikipedia.org Challenge
- 13. Steffen Staab Bias in the Social Web 13 fish, rice lobster, shrimp seafood, fish seafood, shrimp lobster, wine seafood, fish, salmon seafood, shrimp fish, salmon, wine seafood, shrimp lobster, seafood, shrimp coffee coffee, wine coffee italian, wine wine pizza, wine italian, pizza, wine pasta, wine pasta, shrimp seafood fish lobster shrimp crab wine salmon wine pizza coffee italian pasta A. Ahmed, L. Hong and A. Smola, 2013 (following (Yin et al 2011; Sizov 2010)) Existing approaches: Gaussian regions
- 14. Steffen Staab Bias in the Social Web 14 fish, rice lobster, shrimp seafood, fish seafood, shrimp lobster, wine seafood, fish, salmon seafood, shrimp fish, salmon, wine seafood, shrimp lobster, seafood, shrimp coffee coffee, wine coffee italian, wine wine pizza, wine italian, pizza, wine pasta, wine pasta, shrimp seafood fish lobster shrimp crab wine salmon wine pizza coffee italian pasta MGTM 1: Global Topic Clustering
- 15. Steffen Staab Bias in the Social Web 15 fish, rice lobster, shrimp seafood, fish seafood, shrimp lobster, wine seafood, fish, salmon seafood, shrimp fish, salmon, wine seafood, shrimp lobster, seafood, shrimp coffee coffee, wine coffee italian, wine wine pizza, wine italian, pizza, wine pasta, wine pasta, shrimp seafood fish lobster shrimp crab wine salmon wine pizza coffee italian pasta MGTM 2: Determining Neighbourhoods
- 16. Steffen Staab Bias in the Social Web 16 Cluster adjacency Dependencies of document- specific topic distributions Exchange of topic information between clusters MGTM 3: Derived Topic Model
- 17. Steffen Staab Bias in the Social Web 17 Exchange of topic information between clusters MGTM 4: Exchange of Topic Information
- 18. Steffen Staab Bias in the Social Web 18 Exchange of topic information between clusters MGTM 4: Exchange of Topic Information
- 19. Steffen Staab Bias in the Social Web 19 Exchange of topic information between clusters MGTM 4: Exchange of Topic Information
- 20. Steffen Staab Bias in the Social Web 20 γ M N L H G G α0 G Al j 0 θjn w η s d l δl L: #regions M: #documents in cluster N: #words in document G⁰: Global topic distribution G : Cluster-topic distribution G : Document-topic distribution s d MGTM MGTM 5: Composed Model
- 21. Steffen Staab Bias in the Social Web 21 Evaluation: Anectodal, Perplexity, Gaming Gaming study: intrusion detection Precision 8 topics avg / median LGTA 0.60 / 0.58 Basic model 0.64 / 0.58 MGTM 0.78 / 0.75
- 22. Steffen Staab Bias in the Social Web 22 Biases in the Social Machine: The Case of Liquid Feedback
- 23. Steffen Staab Bias in the Social Web 23 ...
- 24. Steffen Staab Bias in the Social Web 24 Online Delegative Democracy CC-BY-SA Ilmari Karonen
- 25. Steffen Staab Bias in the Social Web 25 Delegative Democracy • Between direct and representative democracy CC-BY-SA Ilmari Karonen
- 26. Steffen Staab Bias in the Social Web 26 Delegative Democracy • Between direct and representative democracy • Voters can delegate their vote to other voters CC-BY-SA Ilmari Karonen
- 27. Steffen Staab Bias in the Social Web 27 CC-BY-SA Ilmari Karonen
- 28. Steffen Staab Bias in the Social Web 28 CC-BY-SA Ilmari Karonen
- 29. Steffen Staab Bias in the Social Web 29 CC-BY-SA Ilmari Karonen Delegative Democracy • Between direct and representative democracy • Voters can delegate their vote to other voters • Delegations can be revoked at any time
- 30. Steffen Staab Bias in the Social Web 30 CC-BY-SA Ilmari Karonen Delegative Democracy • Between direct and representative democracy • Voters can delegate their vote to other voters • Delegations can be revoked at any time • Votes are public!
- 31. Steffen Staab Bias in the Social Web 31 Dataset: LiquidFeedback (German Pirate Party)
- 32. Steffen Staab Bias in the Social Web 32 LiquidFeedback – Pirate Party • Observation: 08/2010 – 11/2013 • 13,836 Members • 14,964 Delegations • 499,009 Votes
- 33. Steffen Staab Bias in the Social Web 33 LiquidFeedback – German Pirate Party • Users create initiatives, which are grouped by issues and belong to areas
- 34. Steffen Staab Bias in the Social Web 34 LiquidFeedback – German Pirate Party • Users create initiatives, which are grouped by issues and belong to areas Area: Environmental issues Issue: CO2 output has to be reduced. Initiative: Subsidise wind turbines!
- 35. Steffen Staab Bias in the Social Web 35 LiquidFeedback – German Pirate Party • Users create initiatives, which are grouped by issues and belong to areas Area: Environmental issues Issue: CO2 output has to be reduced. Initiative: Subsidise wind turbines! Areas: 22 Issues: 3,565 Initiatives: 6,517
- 36. Steffen Staab Bias in the Social Web 36 LiquidFeedback – German Pirate Party • Users create initiatives, which are grouped by issues and belong to areas Delegations on global, initiative, issue and area level → “Back-delegations” possible
- 37. Steffen Staab Bias in the Social Web 37 Dataset – First Impressions •
- 38. Steffen Staab Bias in the Social Web 38 Dataset – First Impressions • Voting Weight
- 39. Steffen Staab Bias in the Social Web 39 Dataset – First Impressions • 3,658 members > 10 votes 1,156 members > 100 votes 54 members > 1,000 votesMedian all: 8 votes Median delegating: 42 votes Median delegates: 64 votes
- 40. Steffen Staab Bias in the Social Web 40 Delegation Network • Temporal analysis •
- 41. Steffen Staab Bias in the Social Web 41 Delegation Network • Temporal analysis •
- 42. Steffen Staab Bias in the Social Web 42 Delegation Network • Temporal analysis •
- 43. Steffen Staab Bias in the Social Web 43 Delegation Network • Temporal analysis •
- 44. Steffen Staab Bias in the Social Web 44 Delegation Network • Temporal analysis •
- 45. Steffen Staab Bias in the Social Web 47 The Power of Voters
- 46. Steffen Staab Bias in the Social Web 48 Power • Ability to influence the outcome of a vote
- 47. Steffen Staab Bias in the Social Web 49 Power • Ability to influence the outcome of a vote 5 4 1
- 48. Steffen Staab Bias in the Social Web 50 Power • Ability to influence the outcome of a vote 5 4 same power 1
- 49. Steffen Staab Bias in the Social Web 51 Power Indices • Given voting weights of all voters in a vote: Predict the probability that a given user will be able determine the outcome of a vote Banzhaf power index: Votes are independent Shapley power index: Votes are homogeneous
- 50. Steffen Staab Bias in the Social Web 52 Power • Banzhaf power index: Votes are independent Shapley power index: Votes are homogeneous Potential Power: Measured power in the dataset Exercised Power: Power used to actually turn votes
- 51. Steffen Staab Bias in the Social Web 53 Power Indices • 20 40 60 80 100 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Delegations d Powerp Potential Power Exercised Power
- 52. Steffen Staab Bias in the Social Web 54 Power Indices •
- 53. Steffen Staab Bias in the Social Web 55 Average Approval Rate • (How many users agree with x% of all voted proposals?)
- 54. Steffen Staab Bias in the Social Web 56 Average Approval Rate • Powerful voters tend to vote positive and to agree with the majority
- 55. Steffen Staab Bias in the Social Web 57 Power • Potential Power: Measured power in the dataset Beta power index: Beta distributed approval rate for Banzhaf index Regression power index: Logistic regression for predicting the approval rate – given the voting weight – of the Banzhaf index Beta2 power index: Beta distributed approval rate for Shapley index
- 56. Steffen Staab Bias in the Social Web 58 Novel Power Indices •
- 57. Steffen Staab Bias in the Social Web 59 Novel Power Indices • (Perplexity ~ normalised log likelihood)
- 58. Steffen Staab Bias in the Social Web 60 The Impact of Delegations
- 59. Steffen Staab Bias in the Social Web 61 Approval Rate • → Approval rate decreases with voting experience
- 60. Steffen Staab Bias in the Social Web 62 Approval Rate • → Delegates stabilise the approval rate!
- 61. Steffen Staab Bias in the Social Web 63 Results • Including voting bias in power indices improves the prediction First evaluation of power indices on a large voting history Delegates stabilise the system
- 62. Steffen Staab Bias in the Social Web 64 Conclusions
- 63. Steffen Staab Bias in the Social Web 65 Bias in the Data Bias in the Algorithm Bias in the Social Machine WebObservatory
- 64. Steffen Staab Bias in the Social Web 66 Bias in the Data Bias in the Algorithm Bias in the Social Machine Story telling Under- standing Modelling
- 65. Steffen Staab Bias in the Social Web 67 Institute for Web Science & Technologies Semantic Web Web Search & Data Mining Computational Social Science Interactive Web Software & Services