A Non-parametric Bayesian Approach [WSDM’14]
description
Transcript of A Non-parametric Bayesian Approach [WSDM’14]
A Non-parametric Bayesian Approach [WSDM’14]In this work, we study the problem of user modeling in the search log data and propose a generative model, dpRank, within a non-parametric Bayesian framework. By postulating generative assumptions about a user's search behaviors, dpRank identifies each individual user's latent search interests and his/her distinct result preferences in a joint manner. Experimental results on a large-scale news search log data set validate the effectiveness of the proposed approach, which not only provides in-depth understanding of a user's search intents but also benefits a variety of personalized applications.
Methods
User Modeling in Search Engine LogsHongning Wang, Advisort: ChengXiang Zhai,
Department of Computer Science, University of Illinois at Urbana-Champaign Urbana, IL 61801 USA {wang296,czhai}@Illinois.edu
Group 1
f1
f2
f1
Group k f2
…… ……f1
Group c f2
Group1
A fully generative model for exploring users’ search behaviors 1. Draw latent user groups from DP:
2. Draw group membership for each user from DP:
3.2 Draw query qi for user u accordingly:3.3 Draw click preferences for qi accordingly:
3.1 Draw a latent user group c:3. To generate a query in user u:
Dirichlet Process Prior
Latent User Groups
Modeling of result preferences(𝜋𝑘 )𝑘=1∞ 𝐷𝑃 (𝛾 ,𝜂)
𝜋 1𝜋 2𝜋 3 𝜋𝑒
(1−𝑏) 𝜋𝑒𝑏𝜋𝑒
Group1
Group2
Groupk
…
𝜋 (𝑢1 )
Group2
Groupk
…
𝜋 (𝑢2 )
…Group1
Group2
Groupk
𝜋 (𝑢3 )
q1
q2 q
3
p(Q)(𝜇¿¿1 ,𝜎1
2 , 𝛽1)¿p(Q)
q1
q2 q
3
(𝜇¿¿𝑘 ,𝜎𝑘2 , 𝛽𝑘)¿
p(Q)
q1
q2 q
3
(𝜇¿¿𝑐 ,𝜎𝑐2 , 𝛽𝑐 )¿
𝜇𝑘𝑡 𝑁 (𝜇0 ,𝜎02)𝜎 𝑘𝑡
2 𝐺𝑎𝑚𝑚𝑎 (𝛼0 , 𝛽0)𝛽𝑘𝑣 𝑁 (0 ,𝑎02)
Modeling of search interest𝑝 (𝑞𝑖 ) 𝑁 (𝜇𝑖 ,𝜎𝑘
2 𝐼 )
Gibbs sampling for posterior inference
𝜇𝑘𝑡 𝑁 (𝜇0 ,𝜎02) 𝜎 𝑘𝑡
2 𝐺𝑎𝑚𝑚𝑎 (𝛼0 , 𝛽0) 𝛽𝑘𝑣 𝑁 (0 ,𝑎02)
(𝜋𝑘 )𝑘=1∞ 𝐷𝑃 (𝛾 ,𝜂)
𝑐 𝑖 𝜋𝑢𝑝 (𝑞𝑖 ) 𝑁 (𝜇𝑘 ,𝜎𝑘
2 𝐼 )
𝑝 (𝐷𝑖|𝑞𝑖)= ∏𝑦 𝑖 𝑠>𝑦 𝑖 𝑡
11+exp (− 𝛽𝑘
𝑡 (𝑑𝑖𝑠−𝑑𝑖𝑡))
Experimental Results
Group Top Ranked Queries10 today in history, nascar 2011 schedule, today history, this day in history
9 miami heat, los angeles lakers, liverpool football club, arsenal football, nfl lockout
8 los angeles lakers, arsenal football, the dark knight rises, transformers 3, manchester united
7 the titanic, the bachelorette, cars 2, hangover 2, the voice
6 tree of life, game of thrones, sonic the hedgehog, world of warcraft, mtv awards 2011
5 casey anthony trial, casey anthony jurors, casey anthony, crude oil prices, air france flight 447
4 joplin missing, apple icloud, sony hackers, google subpoena, ford transmission
3 fake tupac story, pbs hackers, alaska earthquake, southwest pilot, arizona wildfires
2 selena gomez, lady gaga, britney spears, jennifer aniston, taylor swift
1 iran, china, libya, vietnam, Syria 0 2 4 6 8 10 12 140123456789
10
Feature ID
Group
ID
�0.8
�0.6
�0.4
�0.2
0
0.2
0.4document agequery match in title
proximity in titlesite authority
• Query distribution in latent user groups • Click preferences in latent user groups
Global model
• Document ranking•
• Yahoo! News search logs• May to July, 2011• 65 ranking features for each Query-Document pair
𝑠 (𝑑 𝑗𝑡 ,𝑞 𝑗 )=1
¿𝑆∨¿∑𝑠∈𝑆
∑𝑘𝑝 (𝑐 (𝑠 )=𝑘|𝑞 𝑗 )𝛽𝑘
( 𝑠 )𝑑 𝑗𝑡 ¿
Aggregated level: information shared by all the users
Individual level: characterize user’s own interest
MAP P@1 P@3 MRRURSVM 0.487 0.298 0.220 0.501GRSVM 0.616 0.446 0.283 0.632TRSVM 0.622 0.459 0.283 0.638IRSVM 0.617 0.449 0.281 0.632dpRank 0.642 0.485 0.290 0.658
A Ranking Model Adaptation Approach [SIGIR’13]In this work, we propose a general ranking model adaptation framework for personalized search. The proposed framework quickly learns to apply a series of linear transformations, e.g., scaling and shifting, over the parameters of the given global ranking model such that the adapted model can better fit each individual user's search preferences. Extensive experimentation based on a large set of search logs from a major commercial Web search engine confirms the effectiveness of the proposed method compared to several state-of-the-art ranking model adaptation methods.
Methods
Timestamp Query Clicks5/29/2012 14:06:04 coney island Cincinnati5/30/2012 12:12:04 drive direction to coney island5/31/2012 19:40:38 motel 6 locations5/31/2012 19:45:04 Cincinnati hotels near coney island
y
x
• Adjust the generic ranking model’s parameters with respect to each individual user’s ranking preferences
y
x𝑓 (𝑥 )=𝑤𝑇 𝑥𝑓 𝑢 (𝑥 )=(𝐴𝑢~𝑤𝑠 )𝑇 𝑥
𝑂 (𝑉 2)
𝐴𝑢=(𝑎𝑔 (1 )𝑢 00 𝑎𝑔 (2)
𝑢⋯ 𝑏𝑔 (1 )
𝑢
⋯ 𝑎𝑔 ( 2)𝑢
⋮ ⋮0 ⋯
⋱ ⋮𝑎𝑔 (𝑉 )𝑢 𝑏𝑔 (1)
𝑢 )𝑂 (𝑉 )
• Linear regression based model adaptation
min𝐴 𝑢
𝐿𝑎𝑑𝑎𝑝𝑡 (𝐴𝑢)=𝐿 (𝑄𝑢 ; 𝑓 𝑢)+𝜆𝑅( 𝐴𝑢)
h𝑤 𝑒𝑟𝑒 𝑓 𝑢 (𝑥 )=(𝐴𝑢~𝑤𝑠 )𝑇 𝑥 𝑎𝑛𝑑~𝑤𝑠=(𝑤𝑠 ,1)
Lose function from any linear learning-to-rank algorithm, e.g., RankNet, LambdaRank, RankSVM
Complexity of adaptation
Induced optimization problem in the same complexity as the original problem
• Instantiation of RankSVM
min𝑤 ,𝜉 𝑖𝑗𝑙
12|w|2+C∑
𝑞𝑖
∑𝑗 , 𝑙𝜉 𝑖𝑗𝑙
𝑠 .𝑡 .𝑤𝑇 Δ𝑥 𝑖𝑗𝑙≥1−𝜉 𝑖𝑗𝑙 ,∀𝑞𝑖 ,𝑥 𝑖𝑗 ,𝑥 𝑖𝑙
𝜉 𝑖𝑗𝑙≥0h𝑤 𝑒𝑟𝑒 𝑦 𝑖𝑗>𝑦 𝑖𝑙𝑎𝑛𝑑 Δ𝑥 𝑖𝑗𝑙=𝑥𝑖𝑗−𝑥 𝑗𝑙
max𝛼
∑𝑡
[1− 𝑓 𝑠 (𝑥𝑡 ) ]𝛼𝑡−12 𝛼
𝑇 [𝐾1 (�⃗� , �⃗� )+𝐾 2 (�⃗� , �⃗� ) ]𝛼𝑠 .𝑡 .0≤𝛼 𝑡≤𝐶 ,∀𝑡
h𝑤 𝑒𝑟𝑒𝐾 1 ( �⃗�𝑡 , �⃗�𝑟 )=∑𝑘 ( ∑
𝑔 (𝑣 )=𝑘𝑤𝑣
𝑠 �⃗�𝑡𝑣 )( ∑𝑔 (𝑣 )=𝑘
𝑤𝑣𝑠 �⃗�𝑟 𝑣)
𝐾 1 ( �⃗�𝑡 , �⃗�𝑟 )= 1𝜎∑
𝑘 ( ∑𝑔 (𝑣 )=𝑘
�⃗�𝑡𝑣 )( ∑𝑔 (𝑣 )=𝑘
�⃗�𝑟 𝑣 )
Pairwise ranking modelMargin rescaling
Non-linear kernels
Experimental Results
# Users # Queries # Documents
Annotation Set - 49,782 2,320,711
User Set 34,827 187,484 1,744,969
• Bing query log: May 27, 2012 – May 31, 2012• 1830 ranking features
• User-level improvement against global model
User Class % Population Method ΔMAP ΔP@1 ΔP@3 ΔMRR
Heavy 6.8RA 0.1843 0.3309 0.0120 0.1832
Cross 0.1998 0.3523 0.0182 0.1994
Medium 14.9RA 0.1102 0.2129 0.0025 0.1103
Cross 0.1494 0.2561 0.0208 0.1500
Light 78.3RA 0.0042 0.0575 -0.0221 0.0041
Cross 0.0403* 0.0894* -0.0021 0.0406*
[10, ∞) queries
[5, 10) queries
(0, 5) queries
Use cross-training to determine feature grouping
per-user basis adaptation baseline
* Indicates p-value<0.01
• Adaptation efficiency
• Query-level improvement against global model