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Detecting Web Spam with CombinedRank. Abhita Chugh Ravi Tiruvury. Motivation. TrustRank Starts with a seed set of good pages Propagates trust to each page reachable by the trusted seed set. Drawback: Can assign a high “Trust” score to a spam page!. 0. Anti-Trust Rank - PowerPoint PPT Presentation
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Detecting Web Spam with CombinedRank
Abhita Chugh Ravi Tiruvury
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Motivation TrustRank
Starts with a seed set of good pages Propagates trust to each page reachable by the trusted
seed set. Drawback: Can assign a high “Trust” score to a spam
page!
1
4
2
5
3
6good
bad
x.yz TrustRank score
7
Anti-Trust Rank Starts with a seed set of spam pages Propagates distrust to each page reachable by the spam
seed set in the inverse webgraph. Benefit: Assigns high “Anti-Trust” scores to spam pages
CombinedRank Combines TrustRank and Anti-Trust Rank Each node in the webgraph has a Trust score and an Anti-Trust score High Trust Score & High Anti-Trust Score
=> Potentially Spam!
Best results with α = 1.0 and β = 0.8
CombinedRank = α * (TrustRank) – β * (Anti-Trust Rank)
ResultsNumber of Spam Pages with Increasing Beta Values
0 0
15
30
675
3233
2
33
246
1164 17
55
4912
2
33
246
1164 17
65
5065
2
33
246
1164 17
73
5450
2
33
246
1164 17
68
5710
2
33
246
1164 17
69
5102
1
10
100
1000
10000
10 100 1000 10000 100000 1000000
No. of Links Selected
Nu
mb
er o
f S
pam
Pag
es TrustRank
β = 0.2
β = 0.4
β = 0.6
β = 0.8
β = 1.0
ResultsNumber of Spam Pages with Increasing Seed Sets
0 0
15
30
675
3233
2
33
246
1164 17
68
5710
10
97
941
4690 66
95 8559
10
94
896
5978
1193
3
1596
8
1
10
100
1000
10000
100000
10 100 1000 10000 100000 1000000
Number of Links Selected
Nu
mb
er
of
Sp
am P
ag
es
TrustRank
CombinedRank ( Seed = 40)
CombinedRank ( Seed = 80)
CombinedRank ( Seed = 120)
ResultsComparison of TrustRank and CombinedRank
1628 23
01
1391
1271
1348 17
88
1637
1761 21
49
3842
2533
1613
1855
1547 19
24
1657 19
66
1594
4089
2803
1165
1116
970
906
1095 15
83
2641
1157
1293
1459
2664
853
1040
657 11
71 1540
1096
1056 16
65
1557
0
0
1000
2000
3000
4000
5000
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7000
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9000
10000
11000
12000
13000
14000
15000
16000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Bucket Number
Nu
mb
er
of
Sp
am P
ag
es
TrustRank
CombinedRank
