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 (before) slide 4

Our shuttle web (before) slide 4

Our shuttle web (after) slide 5

One service for everyone slide 6

Our shuttle web slide 7

Our shuttle web slide 7

This paper in a nutshell ‣ Automatic generation of - route shapes - stop locations - schedules ‣ Online processing for - vehicle-to-route classification - arrival-time prediction slide 8

EasyTracker installation slide 9

EasyTracker installation 1. Obtain smartphone slide 9

EasyTracker installation 1. Obtain smartphone 2. Install EasyTracker app slide 9

EasyTracker installation 1. Obtain smartphone 2. Install EasyTracker app 3. Stick phone in bus slide 9

4. Relax slide 10

System overview GPS GPS slide 11

System overview GPS GPS slide 11

Batch processing slide 12

Batch processing slide 12

Raw GPS traces slide 13

Route map slide 14

Raw GPS traces slide 15

Kernel Density Estimation slide 16

Kernel Density Estimation slide 16

Kernel Density Estimation slide 16

Kernel Density Estimation slide 16

Kernel density estimation n f ( x ) = 1 ˆ X K ( x − x i ) n i =1 1 2 πσ 2 e − x 2 K ( x ) = 2 σ 2 √ slide 17

2-D histogram slide 18

Trajectory density estimate slide 19

Thresholded image slide 20

Map extraction ‣ Davies et al., 2006 slide 21

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 slide 22

Route extraction slide 23

Route extraction slide 23

Route extraction slide 23

Route extraction slide 24

Route extraction slide 24

Route extraction slide 24

Route extraction slide 24

Route extraction slide 24

Route extraction slide 24

Route extraction slide 24

Route extraction slide 24

Route extraction slide 24

Route extraction slide 24

Route extraction slide 24

Route extraction slide 24

Route extraction results slide 25

Welch’s t -Test 0.030 0.023 P-value 0.015 0.008 0 slide 26

Routes separated Real Routes Spurious Routes slide 27

Stop extraction slide 28

Route-labeled GPS traces slide 29

2-D histogram slide 30

Point density estimate slide 31

Thresholded binary image slide 32

Noise in binary image slide 33

Noise reduced binary image slide 34

Stop extraction slide 35

Stop extraction slide 36

Stop extraction performance slide 37

Schedule extraction slide 38

Bus stop arrival times slide 39

Bus stop arrival times slide 39

Bus stop arrival times slide 39

Bus stop arrival times slide 39

Bus stop arrival times slide 39

Bus stop arrival times slide 40

First stop schedule slide 41

Travel time variance slide 42

Last stop arrival times slide 43

Compute mean travel times 1 X a t j − a t travel time (1 , j, t ) = 1 | D | D slide 44

Compute downstream schedules k j t = k 1 t + travel time (1 , j, t ) slide 45

Last stop arrival times slide 46

Last stop schedule slide 47

Schedule accuracy slide 48

Schedule accuracy slide 48

System architecture slide 49

Online processing slide 50

Online processing slide 50

Un-classified buses slide 51

Classified buses slide 52

Hidden Markov model slide 53

Classification accuracy 1.0 0.8 0.6 0.4 0.2 0 Correct Incorrect Unclassified slide 54

Classification delay slide 55

Classification delay slide 55

Arrival time prediction slide 56

Predicting arrival times time until arrival ( s i ) = γ travel time ( s prev +1 , s i )+ (1 − γ ) travel time ( s prev , s i ) slide 57

Arrival time predictions slide 58

Schedule vs. real-time slide 59

Schedule vs. real-time slide 59

Schedule vs. real-time slide 59

System overview GPS GPS slide 60

Come and see our demo! ‣ Thursday, 3:30p-7:30p slide 61

Thanks! Questions?