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Learning User Clicks in Web Search
Ding Zhou et al.The Pennsylvania State
UniversityIJCAI 2007
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What is Click Prediction?
microsoft xbox 360 kinect game1. http://www.xbox.com/zh-TW/kinect2. http://www.xbox.com/en-US/kinect3. http://en.wikipedia.org/wiki/Kinect
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What is Click Prediction?
microsoft xbox 360 kinect game11 http://www.xbox.com/zh-TW/kinect11 http://www.xbox.com/en-US/kinect11 http://en.wikipedia.org/wiki/Kinect
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Click Prediction Model
P(http://www.xbox.com/zh-TW/kinect | microsoft xbox 360 kinect game)
P(http://www.xbox.com/en-US/kinect | microsoft xbox 360 kinect game)
P(http://en.wikipedia.org/wiki/Kinect | microsoft xbox 360 kinect game)
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Two approaches
1. Full Model: PF(http://www.xbox.com/zh-TW/kinect | “microsoft xbox 360 kinect game”)
2. Independent Model: PI(http://www.xbox.com/zh-TW/kinect | microsoft, xbox, 360, kinect, game)
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Two Approaches: Pros and Cons
Full Model High prediction accuracy Low coverage
Independent Model Low prediction accuracy High coverage
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New Approach: Conditional Probability Hierarchy• P(url | microsoft xbox 360 kinect game) =
PF(url | “microsoft xbox 360 kinect game”) + (1-)PI(url | microsoft, xbox, 360, kinect, game)
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New Approach: Conditional Probability Hierarchy• P(url | microsoft xbox 360 kinect game) =
PF(url | “microsoft xbox 360 kinect game”) + (1-)PI(url | microsoft, xbox, 360, kinect, game)
• PI(url | microsoft, xbox, 360, kinect, game) =P(url|microsoft)P(url|xbox)P(url|360)P(url|kinect) P(url|game)
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New Approach: Conditional Probability Hierarchy• P(url | microsoft xbox 360 kinect game) =
PF(url | “microsoft xbox 360 kinect game”) + (1-)PI(url | microsoft, xbox, 360, kinect, game)
• PI(url | microsoft, xbox, 360, kinect, game) =P(url|microsoft)P(url|xbox)P(url|360)P(url|kinect) P(url|game)
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New Approach: Conditional Probability Hierarchy
microsoft xbox 360 kinect game
P(url|microsoft xbox)P(url|360 kinect)
P(url|360 kinect game)
P(url|microsoft xbox 360 kinect game)
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New Approach: Conditional Probability Hierarchy• P(url | microsoft xbox 360 kinect game) =
PF(url | “microsoft xbox 360 kinect game”) + (1-)PI(url | microsoft, xbox, 360, kinect, game)
• PI(url | microsoft, xbox, 360, kinect, game) =f(PF(url | “microsoft xbox”),
(1-)PI(url | microsoft, xbox), PF(url | “360 kinect game”),
(1-)PI(url | 360, kinect, game))
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New Approach: Conditional Probability Hierarchy• P(url | microsoft xbox 360 kinect game) =
PF(url | “microsoft xbox 360 kinect game”) + (1-)PI(url | microsoft, xbox, 360, kinect, game)
is directly proportional to the occurrence frequency of “microsoft xbox 360 kinect game”
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How to predict? What’s the threshold probability for considering
P(url | microsoft xbox 360 kinect game) as a click???
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How to predict? What’s the threshold probability for considering
P(url | microsoft xbox 360 kinect game) as a click??? Not said in paper…
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Experimental Corpus
CiteSeer 1,826,817 query-click pairs
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Prediction Accuracy
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Prediction Coverage
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Accuracy-Coverage Tradeoff