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Independent Cascade Model for Viral Marketing Wonyeol Lee Jinha Kim - - PowerPoint PPT Presentation
Independent Cascade Model for Viral Marketing Wonyeol Lee Jinha Kim - - PowerPoint PPT Presentation
0/19 CT-IC: Continuously activated and Time-restricted Independent Cascade Model for Viral Marketing Wonyeol Lee Jinha Kim Hwanjo Yu Department of Computer Science & Engineering , Korea ICDM 2012 CT-IC model for Viral Marketing 1/19
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Introduction & Motivation
Viral Marketing Influence Maximization Problem Influence Diffusion Models Limitations of Existing Models
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Viral Marketing
- Word of mouth effect > TV advertising
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Influence Maximization Problem [KDDβ03]
π(π)
the expected number of people influenced by a seed set π
arg max
πβπ,|π|=π π(π)
Given a network π» = (π, πΉ), and a budget π, find the π most influential people in a social network
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π(π) Depends On β¦
How influence is propagated through a graph = Influence Diffusion Model
- We need a βrealisticβ diffusion model to apply
influence maximization problem to a βreal-worldβ marketing.
- Existing diffusion models
β IC (Independent Cascade) model [KDDβ03] β LT (Linear Threshold) model [KDDβ03]
CT-IC model for Viral Marketing
π£ π€ ππ(π£, π€)
(newly activated) activation try
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Existing Models Ignore β¦ (1)
- An individual can affect others multiple times.
β NOT contained in βIC model.β
CT-IC model for Viral Marketing
No
Yesterday
GalaxyS3 is awesome
No
Today
GalaxyS3 is awesome
Yes!
Tomorrow
GalaxyS3 is awesome
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Existing Models Ignore β¦ (2)
- Marketing usually has a deadline.
β NOT contained in βall previous models.β
CT-IC model for Viral Marketing
Yes
Yesterday
GalaxyS3 is awesome
Yes
Today
GalaxyS3 is awesome What? Donβt you know GalaxyNote2?
Tomorrow
GalaxyS3 is awesome
7/19
Our Contributions
CT-IC model Properties of CT-IC model CT-IPA algorithm
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- We propose a new influence diffusion model βCT-ICβ for viral
marketing, which generalizes previous models such that
β An individual can affect others multiple times. β Marketing has a deadline.
- An efficient algorithm for influence maximization problem
under CT-IC model?
1) CT-IC model
arg max
πβπ,|π|=π π(π, π)
πππ’ π£, π€ = ππ0 π£, π€ π
π£π€ π’
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Greedy Algorithm [KDDβ03]
- Influence maximization even under IC model is NP-Hard.
- Greedy algorithm:
β Repeatedly select the node which gives the most marginal gain of π π
- Theorem:
π π satisfies non-negativity, monotonicity, submodularity β Greedy guarantees approximation ratio (1 β 1/π).
- CT-IC model satisfies these properties?
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2) Properties of CT-IC model
- We prove the Theorem: In CT-IC model, π β, π’ satisfies
non-negativity, monotonicity, and submodularity.
β Non-negativity: π π, π’ β₯ 0 β Monotonicity: π π, π’ β€ π πβ², π’ for any π β πβ² β Submodularity: π π βͺ π€ , π’ β π π, π’ β₯ π πβ² βͺ π€ , π’ β π πβ², π’ for any π β πβ²
- Thus, Greedy guarantees approximation ratio (1 β 1/π)
even under CT-IC model.
- An efficient method for computing π π, π
under CT-IC model?
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3) CT-IPA algorithm
- Difficulties for computing π π, π under CT-IC model
β Monte Carlo simulation is not scalable. [KDDβ10] β Evaluating π(π) is #P-Hard even under IC model. [KDDβ10] β We show that it is difficult to extend PMIA (the state-of-the-art algorithm for IC model) to CT-IC model!
- We propose βCT-IPAβ algorithm (an extension of IPA [ICDEβ13])
for calculating π π, π under CT-IC model.
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Experiments
Dataset Characteristic of CT-IC model Algorithm Comparison
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Dataset
- We use four real networks:
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Characteristic of CT-IC model (1)
- Model comparison between IC & CT-IC models:
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Characteristic of CT-IC model (2)
- Effect of marketing time constraint π:
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Algorithm Comparison (1)
- Comparison of influence spread:
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Algorithm Comparison (2)
- Comparison of processing time:
β CT-IPA is four orders of magnitude faster than Greedy while providing similar influence spread to Greedy.
CT-IC model for Viral Marketing 1.0s 7.0s 14.5s 14.3s 5.0h 10.0h
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Conclusion
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Conclusion
Existing diffusion models ignore important aspects of real marketing. 1) Propose a realistic influence diffusion model βCT-ICβ for viral marketing. 2) Prove that CT-IC model satisfies non-negativity, monotonicity, and submodularity. 3) Propose a scalable algorithm βCT-IPAβ for CT-IC model.
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Thank You!
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Supplements
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CT-IC model & Other Diffusion models
- Relationship between influence diffusion models:
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Properties of CT-IC model (1)
- Difference between IC & CT-IC models:
β Here, given π» = (π, πΉ), π, π, difference ratio ππ (π», π, π) is defined by where
- The Lemma tells us that
βFor some graphs, CT-IC model is largely different from IC model.β
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Properties of CT-IC model (2)
- Maximum probability path:
β Here, πβ is called a maximum probability path from π£ to π€ if
- The Lemma tells us that
βIt is difficult to generalize PMIA algorithm into CT-IC model.β
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Characteristic of CT-IC model
- Model comparison between IC & CT-IC models:
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Exact Computation of Influence Spread (1)
- Case of an arborescence:
where πππ(π€, π’) is the probability that π€ is activated exactly at time π’ by π.
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- Case of a simple path:
where πππ
π(π£, π€) is the probability that π£ activates π€ in time π along a path π,
Exact Computation of Influence Spread (2)
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Exact Computation of Influence Spread (3)
- Case of a simple path: (proof)
By Lemma 2, By gathering in a matrix,
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IPA Algorithm (1)
- Influence spread of a single node π£:
where π
π£βπ€ = {π = π£, β¦ , π€ |πππ π π£, π€ β₯ π}, ππ£ = {π₯|π π£βπ₯ β π}.
Here, π is a threshold for IPA algorithm.
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IPA Algorithm (2)
- Influence spread of a seed set π:
where π
πβπ€ = {π = π£, β¦ , π€ |π£ β π, πππ π π£, π€ β₯ π}, ππ = {π₯|π πβπ₯ β π}.
Here, π is a threshold for IPA algorithm.
CT-IC model for Viral Marketing