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Mining Fuzzy Moving Object Clusters

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Mining Fuzzy Moving Object Clusters Phan Nhat Hai, Dino Ienco Pascal Poncelet, Maguelonne Teissiere The 8 th International Conference on Advanced Data Mining and Applications (ADMA 2012) 1
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1

Mining Fuzzy Moving Object Clusters

Phan Nhat Hai, Dino Ienco

Pascal Poncelet, Maguelonne Teissiere

The 8th International Conference on Advanced Data Mining and Applications (ADMA 2012)

2

Outline

Background and Motivation

Fuzzy-Closed Swarm Definition

f-CS Miner Algorithm

Experimental Results

3

Trajectory Data

Spatio-Temporal Data. Represented as a set of points, located in space and time.

T=(x1,y1, t1), …, (xn, yn, tn) position in space at time ti was (xi, yi).

4

Mining Movement Patterns

Clustering:Group together similar trajectories.

Consecutive timestamps:Flock [GIS 2006], moving cluster [TKDE 2007], convoy [PVLDB 2008, SSDBM 2010], k-Star [SDM 2009]

Non-consecutive timestamps:Closed swarm [PVLDB 2010]

rGpattern [GIS 2012]

5

Motivation

Completely relaxing consecutive time constraint:

Generate a large number of patterns

Many of them are extraneous

6

Motivation

Propose:Fuzzy time gap

Fuzzy time gap participation index

Questions:Which is relevant time gap?

When the pattern extension should be stopped?

Pattern:o1 and o2 are moving together from {A>B>C} with 60% weak, 20% medium and 20% strong time gaps

7

Outline

Background and Motivation

Fuzzy-Closed Swarm Definition

f-CS Miner Algorithm

Experimental Results

8

Fuzzy Time Gap

weak

medium

9

Fuzzy Time Gap Participation Index

},,{},,{ 321 strongmediumweakAxxxX

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f-ClosedSwarm

at least mino objectsat least mint timestamps

Anti-monotonic

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f-ClosedSwarm

12

Outline

Background and Motivation

f-Closed Swarm Definition

f-CS Miner Algorithm

Experimental Results

13

Straight Forward Approach

Extract all closed swarmsObjectGrowth [PVLDB 2010]

Post-processing to obtain f-closed swarms

Expensive task:Search space: O(2|ODB| x 2|TDB|)

New data is always availableExecute again and again the algorithms on the whole database, i.e. including existing data and new data

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f-CS Miner Algorithm

Objects: transactions

Clusters: items

Pattern: a set of items

15

f-Closed Swarm in Itemset Context

}{ 654321 cccccc

16

General System

17

Outline

Background and Motivation

f-Closed Swarm Definition

f-CS Miner Algorithm

Experimental Results

18

Datasets

Datasets: Swainsoni dataset

43 objects, 4225 different timestamps, gathered from July 1995 to June 1998.

Buffalo dataset165 buffalos, gathered from year 2000 to year 2006.

Synthetic data: 500 objects - 10,000 timestamps.

Hardest condition

LCM algorithm [ICDM FIMI 2004]

19

Effectiveness

Convoy Closed swarm f-Closed swarm

http://www.lirmm.fr/~phan/fcsminer.jsp

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Efficiency (Synthetic Data)

21

TGi Influence

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Conclusion and Future Directions

Propose concept of f-Closed swarm

Propose f-CS Miner

Demonstration system

Extension directions:Mining top-K representative f-closed swarms

Apply on other patterns, i.e. rGpattern [GIS 2012]

23

THANK YOU FOR YOUR ATTENTION Question and Answer

[email protected]@[email protected]@teledetection.fr

The 8th International Conference on Advanced Data Mining and Applications (ADMA 2012)

Demo website: http://www.lirmm.fr/~phan/fcsminer.jsp


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