1 Event Cluster Detection on Flickr Images using a Suffix-Tree Structure Massimiliano Ruocco and Heri Ramampiaro Dept. Of Computer and Information Science Norwegian University of Science and Technology [email protected]Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
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Event Clusters Detection on Flickr Images using a Suffix-Tree Structure
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Event Cluster Detection on Flickr Images using a Suffix-Tree Structure
Massimiliano Ruocco and Heri Ramampiaro
Dept. Of Computer and Information Science Norwegian University of Science and Technology
- Limited to user photo collection! - No Locational Information!
- Event/Place Semantic Identification (Temporal information) [Rattenbury et al. 2007]
- Extraction of event and place semantics for tags assigned to Flickr photos
- Scale-Structure Identification (SSI) method to analyze the tag usage distribution
- SSI is limited for large dataset!
- Location information is not considered!
- Event Tag Detection (Spatial/Temporal information) [Chen, Roy 2009] - Detect event tags from Flickr photos
- As [Rattenbury et al. 2007] use SSI method to analyze the tag usage distribution
- SSI is used over locational and spatial distributions simultaneously
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Problem Definition
Hypothesis
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
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Problem Definition
Hypothesis
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
Something happening in a certain place at a certain time [Yang, Pierce, Carbonell 1999]
25
Problem Definition
Hypothesis
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
Something happening in a certain place at a certain time [Yang, Pierce, Carbonell 1999]
Something happening in a certain place at a certain time with a certain tag
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Problem Definition
Hypothesis
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
Something happening in a certain place at a certain time [Yang, Pierce, Carbonell 1999]
Something happening in a certain place at a certain time with a certain tag
Event Cluster ej {tj=tj, dti=dtj, gi=gj, Ii,Ij ek }
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Problem Definition
Hypothesis
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
Something happening in a certain place at a certain time [Yang, Pierce, Carbonell 1999]
Something happening in a certain place at a certain time with a certain tag
Event Cluster ej {tj=tj, dti=dtj, gi=gj, Ii,Ij ek } Not the opposite !
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Problem Definition
Hypothesis – Landmark clusters
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
time
colosseo!g
Location Event Cluster ek
{tj=tj, dti=dtj, gi=gj, Ii,Ij ek }
…
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Problem Definition
Hypothesis – Landmark clusters
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
time
Location
colosseo!g
dt
Event Cluster ek
{tj=tj, dti=dtj, gi=gj, Ii,Ij ek }
…
30
Problem Definition
Hypothesis – Landmark clusters
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
time
Location
colosseo!g
dt
Event Cluster ek {tj=tj, dti=dtj, gi=gj, Ii,Ij ek } Not the opposite !
Event Cluster ek
Landmark Clusters
{tj=tj, dti=dtj, gi=gj, Ii,Ij ek }
…
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Problem Definition
Hypothesis – Event clusters
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
time
Location
g
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Problem Definition
Hypothesis – Event clusters
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
time
Location
g
dt
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Problem Definition
Hypothesis – Event clusters
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
time
Location
g
dt
applepies!
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Problem Definition
Hypothesis – Event clusters
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
time
Location
g
dt
applepies!
Event Cluster ek {tj=tj, dti=dtj, gi=gj, Ii,Ij ek }
Event Cluster ek
Landmark Clusters
Event Clusters
{tj=tj, dti=dtj, gi=gj, Ii,Ij ek }
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Problem Definition
Hypothesis – Event clusters
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
time
Location
g
dt
applepies!
Event Cluster ek {tj=tj, dti=dtj, gi=gj, Ii,Ij ek } The opposite is true !
Event Cluster ek
Landmark Clusters
Event Clusters
{tj=tj, dti=dtj, gi=gj, Ii,Ij ek }
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Problem Definition
Hypothesis – Event clusters
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
time
Location
g applepies!
Event Cluster ek {tj=tj, dti=dtj, gi=gj, Ii,Ij ek } The opposite is true !
{tj=tj, dti=dtj, gi=gj, Ii,Ij ek }
Event Cluster ek
Landmark Clusters
Event Clusters
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Problem Definition
New Formulation
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
time
Location
g applepies!
time
g applepies!
dt
Event Cluster ek Event
Clusters
Location
=
Sdgt Sgt
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Problem Definition
New Formulation
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
time
Location
g applepies!
time
g applepies!
dt
Event Cluster ek { (dt, g, t) : Sdgt = Sgt} with (Sdgt = ek)
€
∃
Event Cluster ek Event
Clusters
{ (dt, g, t) : Sdgt = Sgt} with (Sdgt = ek)
€
∃
Location
=
Sdgt Sgt
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Preliminary
Suffix-Tree Clustering [Zamir 1998]
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
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Preliminary
Suffix-Tree Clustering [Zamir 1998]
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
- Suffix-Tree based
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Preliminary
Suffix-Tree Clustering [Zamir 1998]
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
- Suffix-Tree based - Mainly used in text (web) document clustering
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Preliminary
Suffix-Tree Clustering [Zamir 1998]
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
- Suffix-Tree based - Mainly used in text (web) document clustering - Three step process:
1 Document cleaning 2 Base clusters identification 3 Base clusters merging
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Preliminary
Suffix-Tree Clustering [Zamir 1998]
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
- Suffix-Tree based - Mainly used in text (web) document clustering - Three step process:
1 Document cleaning 2 Base clusters identification 3 Base clusters merging
- Incremental clustering
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Preliminary
Suffix-Tree Clustering [Zamir 1998]
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
- Suffix-Tree based - Mainly used in text (web) document clustering - Three step process:
1 Document cleaning 2 Base clusters identification 3 Base clusters merging
- Incremental clustering - Cluster label inferred by the tree structure
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Preliminary
Suffix-Tree Clustering [Zamir 1998]
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
- Suffix-Tree based - Mainly used in text (web) document clustering - Three step process:
1 Document cleaning 2 Base clusters identification 3 Base clusters merging
- Incremental clustering - Cluster label inferred by the tree structure - Phrase-Based model
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Preliminary
Suffix-Tree Clustering [Zamir 1998]
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
- Suffix-Tree based - Mainly used in text (web) document clustering - Three step process:
1 Document cleaning 2 Base clusters identification 3 Base clusters merging
- Incremental clustering - Cluster label inferred by the tree structure - Phrase-Based model - Snippet-tolerant
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Preliminary
Suffix-Tree Clustering [Zamir 1998]
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
- Suffix-Tree based - Mainly used in text (web) document clustering - Three step process:
1 Document cleaning 2 Base clusters identification 3 Base clusters merging
- Incremental clustering - Cluster label inferred by the tree structure - Phrase-Based model - Snippet-tolerant - Overlapped clusters
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Preliminary
Suffix-Tree
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
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Preliminary
Suffix-Tree
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
- Given a string S suffix-tree is a Compact Trie containing all the suffixes of S
- Rooted directed tree - Each internal node other than root has at least two children - Each edge leaving a particular node is labelled with a non-empty
substring of S
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Preliminary
Suffix-Tree
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
- Given a string S suffix-tree is a Compact Trie containing all the suffixes of S
- Rooted directed tree - Each internal node other than root has at least two children - Each edge leaving a particular node is labelled with a non-empty
substring of S
Papua ‘apua’ ‘pua’ ‘ua’ ‘a’
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Preliminary
Suffix-Tree
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
- Given a string S suffix-tree is a Compact Trie containing all the suffixes of S
- Rooted directed tree - Each internal node other than root has at least two children - Each edge leaving a particular node is labelled with a non-empty
substring of S
- Suffix-Tree construction performs in linear time (O(n)) ([Ukkonen 1995])
Papua ‘apua’ ‘pua’ ‘ua’ ‘a’
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Algorithm Overview
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
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Algorithm Overview
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
Suffix Tree Construction
Event clusters extraction
Event Clusters merge
Data cleaning Data extension
…
… Primary!Party!Election!Campaign!
… Concert!Music!John! …
Ii = (T, g, dt)
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Algorithm Overview Data Cleaning and Extension
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
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Algorithm Overview Data Cleaning and Extension
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
Top-
20 p
reci
sion
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Conclusion
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
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Conclusion
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
- Novel algorithm for event cluster extraction: - from large amount of Flickr images - Multi-user photo collection - Incremental clustering algorithm
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Conclusion
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
- Novel algorithm for event cluster extraction: - from large amount of Flickr images - Multi-user photo collection - Incremental clustering algorithm
- Extension of STC previously used only to cluster text documents
87
Conclusion
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
- Novel algorithm for event cluster extraction: - from large amount of Flickr images - Multi-user photo collection - Incremental clustering algorithm
- Extension of STC previously used only to cluster text documents - Based on a Suffix-Tree (construction O(n))
88
Conclusion
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
- Novel algorithm for event cluster extraction: - from large amount of Flickr images - Multi-user photo collection - Incremental clustering algorithm
- Extension of STC previously used only to cluster text documents - Based on a Suffix-Tree (construction O(n)) - Automatic annotation of clusters
89
Conclusion
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
- Novel algorithm for event cluster extraction: - from large amount of Flickr images - Multi-user photo collection - Incremental clustering algorithm
- Extension of STC previously used only to cluster text documents - Based on a Suffix-Tree (construction O(n)) - Automatic annotation of clusters - Noise reduction in the tag using extended vocabulary for stopword
removal
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Conclusion
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
- Novel algorithm for event cluster extraction: - from large amount of Flickr images - Multi-user photo collection - Incremental clustering algorithm
- Extension of STC previously used only to cluster text documents - Based on a Suffix-Tree (construction O(n)) - Automatic annotation of clusters - Noise reduction in the tag using extended vocabulary for stopword
removal - Spatial and Time information considered
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Conclusion
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
- Novel algorithm for event cluster extraction: - from large amount of Flickr images - Multi-user photo collection - Incremental clustering algorithm
- Extension of STC previously used only to cluster text documents - Based on a Suffix-Tree (construction O(n)) - Automatic annotation of clusters - Noise reduction in the tag using extended vocabulary for stopword
removal - Spatial and Time information considered - Analysis of different granularity of time and space
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Thanks ( ) for the attention!
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010
谢谢
http://www.idi.ntnu.no/~ruocco/
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Thanks ( ) for the attention!
QUESTIONS?
Massimiliano Ruocco – Event Cluster Detection on Flickr Images using a Suffix-Tree Structure – IEEE ISM2010