Presentation is loading. Please wait.

Presentation is loading. Please wait.

How Long to Wait?: Predicting Bus Arrival Time with Mobile Phone based Participatory Sensing Pengfei Zhou, Yuanqing Zheng, Mo Li -twohsien 2012.9.3.

Similar presentations


Presentation on theme: "How Long to Wait?: Predicting Bus Arrival Time with Mobile Phone based Participatory Sensing Pengfei Zhou, Yuanqing Zheng, Mo Li -twohsien 2012.9.3."— Presentation transcript:

1 How Long to Wait?: Predicting Bus Arrival Time with Mobile Phone based Participatory Sensing Pengfei Zhou, Yuanqing Zheng, Mo Li -twohsien 2012.9.3

2 Outline Introduction System design Evaluation Limitations Conclusion

3 Introduction Why travelers do not like to travel by bus? – Excessively long waiting time Existing methods to predict arrival time – Timetable ( operating hours, time intervals, etc.) – Special location tracking devices on buses Who will pay for this? $$$$$$$$$$$$

4 Objective Crowd-participated approach – Sharing users – Querying users – Backend server Energy friendly – Microphone, accelerometer Mobile Phone

5 Main idea Map the bus routes to a space featured by sequences of nearby cellular towers

6 Challenges Bus Detection Bus Classification Information Assembling

7 System Design

8 Pre-processing Celltower Data 300 meters apart Top-3 strongest cell towers

9 Example

10 Bus Detection Audio detection : short beep audio response Peak at 1 kHz and 3kHz

11 Bus Detection Sliding window, size: 32 samples Empirical threshold: three standard deviation

12 Bus Detection Accelerometer detection – Bus v.s. Rapid train

13 Bus Detection Threshold – Small: trains will be misdetected as buses – Big: miss detection of actual buses

14 Bus Classification Cell tower sequence matching – Smith-Waterman algorithm If u i = C w S j, u i and S j are matching with each other, and mismatching otherwise

15 Bus Classification

16 Overlapped route Survey 50 bus route Range of cell tower: 300-900 meters threshold of celltower sequence length : 7

17 Cell tower Sequence Concatenation

18 Arrival Time Prediction

19 EVALUATION

20 Experimental Methodology Mobile phones – Samsung Galaxy S2 i9100 – HTC Desire Experiment environment – 4 campus shuttle bus routes – 2 SBS transit bus route 179 and 241

21 Bus Detection Performance

22 Bus vs. MRT Train False detection: Driving along straight routes late during night time

23 Bus Classification Performance

24 Arrival Time Prediction

25

26 System Overhead Battery lifetime

27 Limitation and On-going Work Alternative reference points Number of passengers First few bus stops Overlapped routes

28 Conclusion Present a crowd-participated bus arrival time prediction system using commodity mobile phones. Evaluate the system through a prototype system deployed on the Android platform with two types of mobile phones.


Download ppt "How Long to Wait?: Predicting Bus Arrival Time with Mobile Phone based Participatory Sensing Pengfei Zhou, Yuanqing Zheng, Mo Li -twohsien 2012.9.3."

Similar presentations


Ads by Google