EasyTracker Automatic Transit Tracking, Mapping, and Arrival Time - - PowerPoint PPT Presentation

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EasyTracker Automatic Transit Tracking, Mapping, and Arrival Time - - PowerPoint PPT Presentation

EasyTracker Automatic Transit Tracking, Mapping, and Arrival Time Prediction Using Smartphones James Biagioni, Tomas Gerlich, Timothy Merrifield and Jakob Eriksson We love bus trackers! slide 2 Winter in Chicago slide 3 Our shuttle web


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James Biagioni, Tomas Gerlich, Timothy Merrifield and Jakob Eriksson Automatic Transit Tracking, Mapping, and Arrival Time Prediction Using Smartphones

EasyTracker

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We love bus trackers!

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Winter in Chicago

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Our shuttle web (before)

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Our shuttle web (before)

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Our shuttle web (after)

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One service for everyone

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Our shuttle web

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Our shuttle web

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This paper in a nutshell

  • Automatic generation of
  • route shapes
  • stop locations
  • schedules
  • Online processing for
  • vehicle-to-route classification
  • arrival-time prediction

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EasyTracker installation

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EasyTracker installation

  • 1. Obtain smartphone

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EasyTracker installation

  • 1. Obtain smartphone

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  • 2. Install EasyTracker app
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EasyTracker installation

  • 1. Obtain smartphone

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  • 2. Install EasyTracker app
  • 3. Stick phone in bus
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  • 4. Relax

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System overview

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GPS GPS

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System overview

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GPS GPS

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Batch processing

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Batch processing

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Raw GPS traces

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Route map

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Raw GPS traces

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Kernel Density Estimation

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Kernel Density Estimation

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Kernel Density Estimation

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Kernel Density Estimation

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K(x) = 1 √ 2πσ2 e− x2

2σ2

Kernel density estimation

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ˆ f(x) = 1 n

n

X

i=1

K(x − xi)

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2-D histogram

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Trajectory density estimate

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Thresholded image

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  • Davies et al., 2006

Map extraction

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Route extraction

  • Map match GPS traces
  • Viterbi-based map matching
  • based on Thiagarajan, et al. 2009
  • Extract common routes
  • edge subsequence matching
  • statistical test removes spurious results

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Route extraction

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Route extraction

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Route extraction

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Route extraction

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Route extraction

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Route extraction

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Route extraction

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Route extraction

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Route extraction

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Route extraction

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Route extraction

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Route extraction

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Route extraction

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Route extraction

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Route extraction

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Route extraction results

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Welch’s t-Test

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0.008 0.015 0.023 0.030 P-value

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Routes separated

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Real Routes Spurious Routes

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Stop extraction

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Route-labeled GPS traces

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2-D histogram

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Point density estimate

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Thresholded binary image

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Noise in binary image

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Noise reduced binary image

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Stop extraction

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Stop extraction

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Stop extraction performance

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Schedule extraction

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Bus stop arrival times

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Bus stop arrival times

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Bus stop arrival times

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Bus stop arrival times

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Bus stop arrival times

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Bus stop arrival times

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First stop schedule

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Travel time variance

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Last stop arrival times

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travel time(1, j, t) = 1 |D| X

D

at

j − at 1

Compute mean travel times

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Compute downstream schedules

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kj

t = k1 t + travel time(1, j, t)

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Last stop arrival times

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Last stop schedule

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Schedule accuracy

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Schedule accuracy

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System architecture

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Online processing

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Online processing

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Un-classified buses

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Classified buses

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Hidden Markov model

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Classification accuracy

54 0.2 0.4 0.6 0.8 1.0 Correct Incorrect Unclassified

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Classification delay

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Classification delay

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Arrival time prediction

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Predicting arrival times

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time until arrival(si) = γtravel time(sprev+1, si)+ (1 − γ)travel time(sprev, si)

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Arrival time predictions

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Schedule vs. real-time

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Schedule vs. real-time

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Schedule vs. real-time

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System overview

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GPS GPS

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Come and see our demo!

  • Thursday, 3:30p-7:30p

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Questions?

Thanks!