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LAMI 1. User Oriented Trajectory Similarity Search 2. Calibration-free Localization using Relative Distance Estimations 3. From GPS Traces to a Routable.

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Presentation on theme: "LAMI 1. User Oriented Trajectory Similarity Search 2. Calibration-free Localization using Relative Distance Estimations 3. From GPS Traces to a Routable."— Presentation transcript:

1 LAMI 1. User Oriented Trajectory Similarity Search 2. Calibration-free Localization using Relative Distance Estimations 3. From GPS Traces to a Routable Road Map Radu Mariescu-Istodor 10.2.2014

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3 Similarity Search Naive solution is to compare Every pair of points (10 8 ) From reference route and Every route in DB (10 5 ) Average route length ~1000 points. 10 8 haversines ~ 30 minutes

4 Limiting the space R-tree indexed points => easy to conduct range checks Naive solution is to compare Every pair of points (10 8 ) From reference route and Every route in DB (10 5 ) the routes that have at least one point in one of the squares

5 Reducing range check calculations Grouping several squares into a bounding rectangle

6 How to group? Dead Space Limiting the Dead Space as much as possible

7 How to limit the Dead Space?

8 Longest Common Subsequence Heaviest Common Subsequence O(N 2 )

9 User Oriented Similarity Heaviest Common Subsequence User defined Regions

10 Improve speed of HCSS Heaviest Grouped Subsequence HCSS ≤ HGSS 1. HGSS = 492 2. HGSS = 452 3. HGSS = 412 4. HGSS = 301 ………………. HCSS ?

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12 Purpose How to calculate the position of mobile devices that do not posses a GPS sensor

13 Centroid and Fingerprinting

14 How it works? Cell1=50% Cell2=80% Cell3=60% GPS signature

15 How it works? Cell1=50% Cell2=80% Cell3=60% Cell1=80% Cell3=20% Cell5=30% Cell6=20% Common Cells = 2 Uncommon Cells = 3 Spearman = ? Feature : (Experimentally deduced)

16 Regression Formula (Experimentally deduced) Fitted from GPS phones Features ={Common, Uncommon, Spearman}

17 Estimating locations

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19 Objective: Road Network from GPS Tracks

20 Merging nearby trajectories Gravity

21 Merging nearby trajectories GravitySpring Resultant force applied in small iterations until change insignificant

22 Traces of opposite directions Method so far Desired output:

23 Repelling force Sign tells if same direction or not ≠ ?

24 Solution

25 Banding issue expecting Gaussian Distribution

26 Matching the Gaussians expecting Gaussian Distribution Finding centroids gives number of bands


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