real-life rating algorithm
TRANSCRIPT
Copyright 2007 Digital Enterprise Research Institute. All rights reserved.
Digital Enterprise Research Institute www.deri.ie
Ranking System based on Social Network of Domain Experts
Mateusz MarmołowskiMay 28, 2008
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Motivation
Rating / Ranking / Voting Insufficient rating algorithms Real-life situations, human behaviours
Frienship factor Domain experts
Masters Thesis ;-)
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Our goals
New, real-life rating algorithm Fully automated and efficient approach Friendship consideration – social network Expertise collection REST SOA for simple access
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Rating Algorithm - agenda
Rating Calculation Friendship influence Domain knowledge Multiple domains User Weight Weighted Rate Bayesian Weighted Rate
Expertise Calculation Weighted Expertise Value Activity factor Final expertise calculation Expertise propagation process
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Rating Algorithm
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Rating Calculation
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RC – Friendship influence
2
),(
),(%200
),( yx
yx
yx
UUDISTANCE
UUFRIENDSHIP
UUFW
Range: [50 – 100%]
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RC – Domain knowledge
Domain expertise Parameter α – for amateurs Inaccurate domain adjustment
Generalization and particularization Expertise propagation
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RC – Multiple domains
Resource with multiple domains assigned Solution - geometric series
MD factor:
d
q
q
dMD
d
1
1
)( 5.0q
d MD(d)
1 100%
2 75%
3 58%
4 47%
5 39%
q
qaS
n
n
1
11
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RC – User Weight
Each rate is being weighted with UW Frienship with the author Expertise in resource’s domains
User Weight for a specific resource:
)(*
)(*),(),(),,( 1
dMDd
dMDDUEXPUUFWRUUUW
d
iix
yxjyx
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RC – Weighted Rate
Weighted Rate for resource Rate given by user User Weight The author of The number of rates for a resource
)(
1
)(
1
),,(
),,(*),()(
j
j
RRN
ijji
RRN
ijauthoriji
j
RUUUW
RUUUWRUURRWR
)( jRWR
),( ji RUUR
),,( jauthori RUUUW
authorU
)( jRRN
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RC – Bayesian Weighted Rate
votesnumthisvotesnumavg
ratingthisvotesnumthisratingavgvotesnumavgBR
____
_*___*__
votesnumavg __
ratingavg _
votesnumthis __
ratingthis _
- The average number of votes of all resources
- The average rating of all resources’ ratings- The number of votes for this
resource
- The rating of this resource
)(_
)(*)(_*_)(
j
jjj RRNnumavg
RWRRRNvalueneutralnumavgRBWR
Final formula:
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Expertise Calculation
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EC – Weighted Expertise Value
Separately calculated for each domain and user Based on:
BWR for each resource Number of rates for that resource Mutiple Domain factor
Rating scale normalization
scaleratingdMDRRN
RBWRdMDRRN
DUWEV
j
r
jj
r
jjjj
ky _
%100*
)(*)(
)(*)(*)(
),(
1
1
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EC – Final expertise calculation
EXP value is used for User Weight calculation EXP strongly depends on WEV WEV recalculation in case of new rates
Parameter α for amateurs (no published resources)
0),(,),(
0),(,),(
kyky
ky
ky DUWEVforDUWEV
DUWEVforDUEXP
scalerating _
%100
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Expertise propagation
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Expertise propagation – step 1
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Expertise propagation – step 2
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Expertise propagation – step 3
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Summary
Implementation in progress Integration with MarcOnt Portal Masters Thesis Publication
DERILion Deliverable D1.6.3 - Real-life Rating Algorithm
Thank you.