Jtel 2010 na li

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Swiss Federal Institute of Technology in Lausanne EPFL, CH-1015 Lausanne, Switzerland Trust Modeling and Evaluation in Web 2.0 Collaborative Learning Social Software Na Li Swiss Federal Institute of Technology in Lausanne (EPFL) JTEL 2010 June 7-June 11

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Transcript of Jtel 2010 na li

Page 1: Jtel 2010 na li

Swiss Federal Institute of Technology in Lausanne EPFL, CH-1015 Lausanne, Switzerland

Trust Modeling and Evaluation in Web 2.0 Collaborative Learning Social Software

Na Li

Swiss Federal Institute of Technology in Lausanne (EPFL)

JTEL 2010 June 7-June 11

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Swiss Federal Institute of Technology in Lausanne EPFL, CH-1015 Lausanne, Switzerland

Outline

•Research Questions•Current Progress•Future Work

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Swiss Federal Institute of Technology in Lausanne EPFL, CH-1015 Lausanne, Switzerland

Research Questions• Lots of Web 2.0 learning environments bring

about large amount of user-generated content▫What should we trust?▫Who should we trust?

RSS Feeds

Pictures

Documents

Videos

Wiki Pages

Pictures

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Swiss Federal Institute of Technology in Lausanne EPFL, CH-1015 Lausanne, Switzerland

Research Questions•Trust Measurement

▫Evaluate quality of user-generated content▫Recommend useful resources ▫Privacy management

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Swiss Federal Institute of Technology in Lausanne EPFL, CH-1015 Lausanne, Switzerland

Current Progress

•Trust-based rating prediction▫Quality evaluation in open learning

environment▫Filter helpful learning resources, people

and group activities

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Swiss Federal Institute of Technology in Lausanne EPFL, CH-1015 Lausanne, Switzerland

Trust-Based Rating Prediction Approach

•Basic idea▫What influences rating opinion:

similarity and familiarity▫People tend to trust the opinions of

acquaintance and those having similar interests and tastes.

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Swiss Federal Institute of Technology in Lausanne EPFL, CH-1015 Lausanne, Switzerland

Trust-Based Rating Prediction Approach•Trust measurement

▫Multi-relational trust metric▫Build a “Web of Trust” for a particular user

using heterogeneous types of relationships

Trust

How Much?

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Swiss Federal Institute of Technology in Lausanne EPFL, CH-1015 Lausanne, Switzerland

Trust-Based Rating Prediction Approach•Trust propagation•Propagation distance (PD)

Alice

French Learning Activity

Is Member

ArticleCreate

Video

Rate

Propagate

LuisHas Member

Rated by Sara

Rated byBen

Bob

Commented by

Jack

Created by

Propagate PropagatePD

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Swiss Federal Institute of Technology in Lausanne EPFL, CH-1015 Lausanne, Switzerland

Trust-Based Rating Prediction Approach•Rating prediction from a user to an item

▫Using user’s “Web of Trust”▫People in “Web of Trust” are seen as trustable▫Average of all the rating scores given by

trustable people, weighted by their trust value

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Swiss Federal Institute of Technology in Lausanne EPFL, CH-1015 Lausanne, Switzerland

Evaluation and Results•Using Remashed data set

▫50 users, 6000 items, 3000 tags and 450 ratings

▫“Leave-one-out” method▫Compare “predicted score – actual score”

deviation of trust-based prediction and simple average

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Swiss Federal Institute of Technology in Lausanne EPFL, CH-1015 Lausanne, Switzerland

Evaluation and Results•Change parameters

▫Weights for relationships doesn’t make a significant difference in rating prediction

▫Increasing size of trust network might add noise, lead to bigger prediction error

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Swiss Federal Institute of Technology in Lausanne EPFL, CH-1015 Lausanne, Switzerland

Future Work

• Future deploy and evaluation will be conducted in a collaborative learning platform, namely Graaasp(graaasp.epfl.ch)

• Trust-based privacy management

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Swiss Federal Institute of Technology in Lausanne EPFL, CH-1015 Lausanne, Switzerland

Questions?