Landmark-Based User Location Inference in Social Media

Landmark-Based User Location Inferencein Social MediaYUTO YAMAGUCHI†, TOSHIYUKI AMAGASA †

AND HIROYUKI KITAGAWA†

†UNIVERSITY OF TSUKUBA

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COSN 2013 - Yuto Yamaguchi 1

LOCATION-RELATED INFORMATION

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Eating seafood !!!

I’m at Logan airport

Profile

Residence: Tokyo, Japan

COSN @ northeastern

APPLICATIONSVarious Researches using Home Locations Outbreak Modeling [Poul+, ICWSM’12] Real-World Event Detection [Sakaki+, WWW’12] Analyzing Disasters [Mandel+, LSM’12]

Other Useful Applications Location-aware Recommender [Levandoski+, ICDE’12] Merketing, Ads Disaster Warning

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OUR PROBLEMLocation profiles are not available for … 76% of Twitter users [Cheng et al., CIKM’10] 94% of Facebook users [Backstrom et al.,

WWW’10]

This reduces opportunities of location information

　　　　　　　　　　　　　　　 User Home Location Inference

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USER HOME LOCATION INFERENCE Content-Based Approaches

[Cheng et al., CIKM’10] [Kinsella et al., SMUC’11] [Chandra et al., SocialCom’11]

Graph-Based Approaches [Backstrom et al., WWW’10] [Sadilek et al., WSDM’12] [Jurgens, ICWSM’13]

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Our focus

GRAPH-BASED APPROACH (1/2)Basic Idea

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Boston

Boston

Boston Chicago

New York Boston?

friends

GRAPH-BASED APPROACH (2/2)Closeness Assumption

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Friends

Not friends

Spatially close

Spatially distant

Really close?

60% are 100km distant

CONCENTRATION ASSUMPTION

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Boston

Boston?

LANDMARK

Unknown

NYChicago

LANDMARKS 　　　　　　　　13/10/08 9COSN 2013 - Yuto Yamaguchi

REQUIREMENTS Small Dispersion

Large Centrality

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EXAMPLES IN TWITTER

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LANDMARKS MAPPING

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Red: all usersBlue: landmarks

PROPOSED METHOD　　　　13/10/08 13COSN 2013 - Yuto Yamaguchi

OVERVIEWProbabilistic Model

Modeling

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Each user has his/her location distribution

Location inference = Selecting the location with the largest probability densitylocation set

LANDMARK MIXTURE MODEL

DOMINANCE DISTRIBUTIONSpatial distribution of followers’ home locations Modeled as Gaussian

Landmarks have small covariances many followers at the center

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latitude

longitude

manyfollowers

fewfollowers

LANDMARK MIXTURE MODEL (LMM)

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Inferencetarget user

follow

Landmark

Non-landmark

Non-landmark

Dominancedistribution

Mixtureweight

Large weight for landmark

MIXTURE WEIGHTS

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Proportional to centrality

Landmark Non-landmark

Large mixture weight Small mixture weight

CONFIDENCE CONSTRAINTIf the distribution does not have a clear peak,

we should not infer the location of that user

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High precision but low recall

CENTRALITY CONSTRAINTWe can reduce the cost by ignoring non-landmarks

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low cost but low recall

Inferencetarget user

follow

Landmark

Non-landmark

Non-landmark

EXPERIMENTS　　　　　　　　　13/10/08 20COSN 2013 - Yuto Yamaguchi

DATASETTwitter dataset provided by [Li et al., KDD’12] 3M users in the U.S. 285M follow edges

Geocode their location profiles for ground truth 465K users (15%) labeled users

Test set 46K users (10% of labeled users)

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PERFORMANCE COMPARISON

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Compared three methods LMM: our method UDI: [Li+, KDD’12] Naïve: Spatial median

EFFECT OF CONFIDENCE CONSTRAINT

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p0

We can adjust the trade-off between precision and recall

EFFECT OF CENTRALITY CONSTRAINT

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c0 We can adjust the trade-off between cost and recall

CONCLUSIONIntroduced the concentration assumptioninstead of widely-used closeness assumption There exist landmarks

Proposed landmark mixture model Outperforms the state-of-the-art method Confidence / Centrality constraint

Future work Other application of landmarks

Recommending landmarks or their tweets

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Documents

Landmark-Based User Location Inference in Social Media