Semantic Labeling of Places

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Semantic Labeling of Placesbased on Phone Usage Features

using Supervised LearningA. Rivero-Rodriguez, H. Leppäkoski ,R. Piché

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19.11.2014

Tampere University of TechnologyTampere, Finlandwww.tut.fi/posgroup

November 21, 2014Corpus Christi, Texas, USAUPIN-LBSContext inference and awareness

This talk describes the design of the algorithmsfor a smartphone to learn your significantplaces

Training data Features Classifiers

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MDC dataset

Idiap and NRC-LausanneLausanne Data Collection Campaign (2009-2011)Records of 200 users over 18 monthsCaptures all types of informationUsers provide extra information (labels!)Anonymisation46 GB of data!

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Training Data

Active Phone Usagecalls, messagescalendar, contactsapplication usage

Pasive Phone Usagenetwork informationsystem Informationlocation & movement

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Features AvailableTraining Data

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The places were identified byclustering, then labeled by the userTraining Data

200 m

Friend’s Home

Restaurant

Work

Home

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Call logscallsTimeRatiocallsPerHour

AccelerometeridleStillRatiowalkRatiovehicleRatiosportRatio

SystemdurationstartHourendHournightStaybatteryAvgchargingTimeRatiosysActiveRatiosysActStartsPerHour

Features

We selected 14 features that could beused by a place-labelling application

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Features

We considered two different datarepresentations

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visits_20min.csvplaces.csv

Definitionsfor DB queries Make queries

system

call logs

accel activity

start times,end times,

used ids,place labels

feature vectorsfor places

Accumulate times & counts,weight averages

for eachuser & place

Compute times,counts, averages

for eachvisit

Compute ratios Compute ratios

feature vectorsfor visits

Features

We preprocessed the data to obtainthe features for both approaches

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X | , = | B| )

( )

We applied five popular classificationmethods to the dataClassifiers

Naïve Bayes (NB)

Decision Tree (DT)

Bagged Tree (DT)

Neural Networks (NN)

K-nearest neighbors (K-NN)

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0

1000

2000

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9000

10000

H

W

O

70%

W

H

O

28%

O

HW

65%

H

W

O

82%

W

H

O80%

O

H

W12%

H

W

O80%

W

HO

89%

O

H

W

7%

H

WO

96%

W

H

O29%

O

H

W2%

H

WO

93%

W

H

O25%

O

H

W7%

Num

bero

fcas

es(v

isits

)Well Classified Misclassified

NB53%

DT75%

BT77%

NN61%

KNN58%

H: HomeW: WorkO: Others

Results - Visits approachClassifiers

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0

5

10

15

20

25

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H

O97%

W

HO

88%

O

H

W

69%

H

O

86%

W

HO

91%

O

H

W

67%

H

O97%

W

HO

91%

O

H

W

69%

H

O

93%

W

H

O85%

O

H

W

69%

H

O

86%

W

H

O

79%

O

H

W

53%

Num

bero

fcas

es(v

isits

)Well Classified Misclassified

NN71%

DT81%

NB84%

BT85%

KNN71%

H: HomeW: WorkO: Others

Results - Places approachClassifiers

Naive Bayes and Bagged Decision Tree with Places data-representation are bestNN and K-NN underperform and are computationally demandingMost relevant features are: night stay, stay duration, start time,battery status, idle time

Other classifiers (logistic regresion, support vector machine)Combine Places and Visits data-representations

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Classifiers

Results & Future Work

Alejandro Riveroalejandro.rivero@tut.fi

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